WO2024106339A1 - Power converter and method for controlling power converter circuit - Google Patents

Power converter and method for controlling power converter circuit Download PDF

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Publication number
WO2024106339A1
WO2024106339A1 PCT/JP2023/040591 JP2023040591W WO2024106339A1 WO 2024106339 A1 WO2024106339 A1 WO 2024106339A1 JP 2023040591 W JP2023040591 W JP 2023040591W WO 2024106339 A1 WO2024106339 A1 WO 2024106339A1
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Prior art keywords
current command
power conversion
control
command
value
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PCT/JP2023/040591
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French (fr)
Japanese (ja)
Inventor
徹 杉浦
徹郎 児島
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株式会社日立製作所
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Publication of WO2024106339A1 publication Critical patent/WO2024106339A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/34—Arrangements for starting

Definitions

  • the present invention relates to a power conversion device and a method for controlling a power conversion circuit.
  • the power conversion device When operating railway vehicles, the power conversion device is started from a stopped state, the vehicle accelerates, the power conversion device is stopped, the vehicle enters a coasting state where the vehicle runs by inertia, and from this state the power conversion device is restarted and the vehicle is accelerated or decelerated.
  • This is a common operation.
  • no voltage is applied to the induction motor, but current continues to flow inside the induction motor for a while after the power conversion device is stopped. This current is consumed by the internal resistance of the induction motor and gradually decays, but magnetic flux continues to be generated until the current disappears, so residual magnetic flux exists inside the induction motor. If the power conversion device is restarted when this residual magnetic flux is large, adverse effects such as damage to the power conversion device due to the generation of excessive current and deterioration of the vehicle's ride comfort due to the generation of excessive torque may occur.
  • Patent Document 1 discloses a control device for a power conversion device that has the function of sufficiently attenuating magnetic flux when stopping an induction motor, and includes a voltage calculation unit that generates a voltage command based on a current command, and a PWM calculation unit that outputs a gate pulse signal for the power conversion circuit based on the voltage command.
  • Patent Document 1 does not take into consideration the control required when the power conversion device is shut off during the ramp-up of the magnetic flux command. As a result, in such a case, there is a risk that the residual magnetic flux inside the induction motor will not be sufficiently attenuated.
  • a power conversion device includes a power conversion circuit that converts DC power to AC power to drive an induction motor, and a control device that outputs a gate pulse signal to the power conversion circuit to control the power conversion circuit, wherein the control device determines a current command and a magnetic flux command used in generating the gate pulse signal, and is capable of holding a hold value corresponding to the value of the magnetic flux command immediately before the current command starts to fall, and when shutting off the power conversion circuit, determines the current command and the magnetic flux command based on the held value.
  • a control method for a power conversion circuit is a control method for a power conversion circuit that converts DC power to AC power to drive an induction motor, the control method comprising the steps of: determining a current command and a magnetic flux command; generating a gate pulse signal based on the current command and the magnetic flux command; outputting the gate pulse signal to the power conversion circuit; holding a hold value corresponding to the value of the magnetic flux command immediately before the current command starts to fall; and, when shutting off the power conversion circuit, determining the current command and the magnetic flux command based on the held value.
  • the residual magnetic flux inside the induction motor can be sufficiently attenuated.
  • FIG. 1 is a diagram showing a configuration of a power conversion device according to an embodiment of the present invention
  • FIG. 2 is a functional block diagram showing details of a control device according to the first embodiment of the present invention.
  • FIG. 2 is a control block diagram showing details of a pattern generating unit according to the first embodiment of the present invention.
  • 11 is a diagram showing an example of each command and state quantity when cut-off control is performed after completion of the rise of the d-axis magnetic flux command.
  • FIG. 1 is a diagram showing an example of each command and state quantity when cutoff control is performed before the start-up of a d-axis magnetic flux command is completed by a conventional control method.
  • FIG. 1 is a diagram showing a configuration of a power conversion device according to an embodiment of the present invention
  • FIG. 2 is a functional block diagram showing details of a control device according to the first embodiment of the present invention.
  • FIG. 2 is a control block diagram showing details of a pattern generating unit according to the first embodiment of the present
  • FIG. 4 is a diagram showing an example of each command and a state quantity in a case where cutoff control is performed before the start-up of a d-axis magnetic flux command is completed in the power conversion device according to the first embodiment of the present invention.
  • FIG. FIG. 11 is a functional block diagram showing details of a control device according to a second embodiment of the present invention.
  • FIG. 11 is a control block diagram showing details of a pattern generating unit according to a second embodiment of the present invention.
  • FIG. 13 is a control block diagram showing details of a pattern generating unit according to a third embodiment of the present invention.
  • FIG. 11 is a diagram showing an example of each command and a state quantity in a case where cutoff control is performed before the start-up of a d-axis magnetic flux command is completed in a power conversion device according to a third embodiment of the present invention.
  • First Embodiment Fig. 1 is a diagram showing the configuration of a power conversion device according to an embodiment of the present invention.
  • the power conversion device shown in Fig. 1 includes a power conversion circuit 1 that is connected to an induction motor 3 and converts DC power supplied from an external DC power source into AC power and outputs the AC power to the induction motor 3 to drive the induction motor 3, and a control device 2 that controls the power conversion circuit 1.
  • the power conversion circuit 1 has a U-phase upper arm element 5a, a U-phase lower arm element 5b, a V-phase upper arm element 5c, a V-phase lower arm element 5d, a W-phase upper arm element 5e, and a W-phase lower arm element 5f, which are semiconductor switching elements.
  • the U-phase upper arm element 5a and the U-phase lower arm element 5b, the V-phase upper arm element 5c and the V-phase lower arm element 5d, and the W-phase upper arm element 5e and the W-phase lower arm element 5f are connected in series in the power conversion circuit 1, forming upper and lower arm circuits for the U, V, and W phases.
  • Power lines leading to the induction motor 3 are connected between the upper arm elements 5a, 5c, 5e and the lower arm elements 5b, 5d, 5f of each of these upper and lower arm circuits.
  • the power conversion circuit 1 converts DC power supplied from a DC power source into three-phase AC power by switching and driving the semiconductor switching elements 5a to 5f in response to the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 output from the control device 2.
  • the converted three-phase AC power is output from the power conversion circuit 1 to the induction motor 3 via the power lines of each phase, thereby controlling the drive of the induction motor 3 by the power conversion device of this embodiment.
  • the DC power supplied from the DC power source is smoothed by the smoothing capacitor 4 and input to the power conversion circuit 1.
  • the terminal voltage of the smoothing capacitor 4 i.e., the voltage Ecf of the DC power input to the power conversion circuit 1, is detected by the DC voltage sensor 6, and the detected value is input to the control device 2.
  • a U-phase current sensor 7a, a V-phase current sensor 7b, and a W-phase current sensor 7c are installed on the power lines of each phase between the power conversion circuit 1 and the induction motor 3 to detect the U-phase current iu, the V-phase current iv, and the W-phase current iw that flow through the induction motor 3.
  • the detection results of each phase current by these current sensors 7a to 7c are input to the control device 2.
  • the control device 2 generates gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 based on the detection value of the DC voltage Ecf by the DC voltage sensor 6 and the detection values of the U-phase current iu, V-phase current iv, and W-phase current iw by the current sensors 7a to 7c, and outputs them to the power conversion circuit 1.
  • FIG. 2 is a functional block diagram showing details of the control device 2 according to the first embodiment of the present invention.
  • the control device 2 has the following functional blocks: a current command generation unit 8, a pattern generation unit 9, a coordinate conversion unit 10, a rotational speed estimation unit 11, a frequency command generation unit 12, a voltage command generation unit 13, and a pulse command generation unit 14.
  • the control device 2 is configured using, for example, a microcomputer having a CPU, memory, etc., and can realize functions corresponding to each functional block in FIG. 2 by executing a predetermined program in the CPU. Note that some or all of the functions of the control device 2 may be realized using a logic circuit such as an FPGA (Field Programmable Gate Array).
  • FPGA Field Programmable Gate Array
  • the control device 2 receives a control command cmd from the outside to operate or stop the power conversion circuit 1.
  • the current command generation unit 8 generates and outputs a d-axis current command Idp1 and a q-axis current command Iqp according to the control command cmd. For example, when a control command cmd to operate the power conversion circuit 1 is input, the current command generation unit 8 generates a d-axis current command Idp1 and a q-axis current command Iqp so that the AC power required to drive the induction motor 3 with a specified torque is output from the power conversion circuit 1.
  • the pattern generation unit 9 calculates the excitation current command Idp2 and the d-axis magnetic flux command ⁇ dp based on the d-axis current command Idp1 input from the current command generation unit 8, and outputs them to the voltage command generation unit 13.
  • the excitation current command Idp2 is a command value for the current in the d-axis direction, which is the direction of the rotating magnetic field of the induction motor 3. It is equal to the d-axis current command Idp1 during normal operation of the power conversion circuit 1, and corresponds to a corrected value obtained by correcting the d-axis current command Idp1 to attenuate the magnetic flux of the induction motor 3 when the power conversion circuit 1 is stopped.
  • the pattern generation unit 9 switches the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command ⁇ dp depending on the control state of the induction motor 3.
  • the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command ⁇ dp by the pattern generation unit 9 will be described in detail later.
  • the coordinate conversion unit 10 performs a rotational coordinate conversion on the U-phase current iu, V-phase current iv, and W-phase current iw detected by the current sensors 7a to 7c, respectively, to determine the d-axis current detection value Idf and the q-axis current detection value Iqf, and outputs these current detection values to the rotation speed estimation unit 11. Note that the coordinate conversion unit 10 determines the d-axis current detection value Idf and the q-axis current detection value Iqf by defining the direction of the rotating magnetic field of the induction motor 3 as the d-axis direction and the direction of the current flowing to generate torque as the q-axis direction.
  • the rotational speed estimation unit 11 estimates the rotor angular frequency of the induction motor 3 based on the excitation current command Idp2 and the q-axis current command Iqp input from the pattern generation unit 9 and the current command generation unit 8, respectively, and the d-axis current detection value Idf and the q-axis current detection value Iqf input from the coordinate conversion unit 10, and outputs the estimation result as the rotor angular frequency estimate value ⁇ re.
  • the frequency command generating unit 12 receives the d-axis magnetic flux command ⁇ dp calculated by the pattern generating unit 9, the q-axis current command Iqp generated by the current command generating unit 8, and the rotor angular frequency estimate ⁇ re estimated by the rotational speed estimating unit 11. Based on this input information, the frequency command generating unit 12 calculates the angular frequency of the AC voltage applied to the induction motor 3, and outputs it as the primary angular frequency ⁇ 1.
  • the voltage command generating unit 13 receives as input the DC voltage Ecf detected by the DC voltage sensor 6, the excitation current command Idp2 and the d-axis magnetic flux command ⁇ dp calculated by the pattern generating unit 9, the q-axis current command Iqp generated by the current command generating unit 8, the rotor angular frequency estimate ⁇ re calculated by the rotational speed estimating unit 11, and the primary angular frequency ⁇ 1 calculated by the frequency command generating unit 12.
  • the voltage command generating unit 13 calculates the modulation factor Vc and voltage command deflection angle ⁇ of the power conversion circuit 1 based on this input information, and outputs the calculation result as a voltage command for the output voltage from the power conversion circuit 1 to the induction motor 3.
  • the pulse command generating unit 14 calculates gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 for the semiconductor switching elements 5a to 5f of the power conversion circuit 1 based on the modulation factor Vc and voltage command argument ⁇ , which are voltage commands generated by the voltage command generating unit 13, and the primary angular frequency ⁇ 1 determined by the frequency command generating unit 12.
  • the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 determined by the pulse command generating unit 14 are output from the control device 2 to the power conversion circuit 1 as described above, and are used to control the drive of each of the semiconductor switching elements 5a to 5f of the power conversion circuit 1.
  • FIG. 2 shows an example of a power conversion device that realizes speed sensorless control by using the rotation speed estimation unit 11 to determine the rotor angular frequency estimate ⁇ re of the induction motor 3.
  • the present invention will be explained below using this example, but the present invention can also be applied to speed sensor-equipped control in which a speed sensor is provided instead of the rotation speed estimation unit 11 and the rotation speed of the induction motor 3 is detected by this speed sensor.
  • the configuration of the present invention is not limited to the embodiment described below.
  • FIG. 3 is a control block diagram showing details of the pattern generation unit 9 according to the first embodiment of the present invention.
  • the pattern generation unit 9 is configured by combining a switching contact 15, an adder 16, a switching contact 17, a delay element 18, a subtractor 19, a gain 20, an integral element 21, a switching contact 22, a gain 23, a switching contact 24, a delay element 25, a multiplier 26, a divider 27, a gain 28, and a differential element 29, for example, as shown in FIG. 3.
  • the pattern generation unit 9 switches the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command ⁇ dp depending on the control state of the induction motor 3. Specifically, the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command ⁇ dp in the pattern generation unit 9 is switched between a case where the operation of the power conversion circuit 1 is controlled so that AC power is output from the power conversion circuit 1 to drive the induction motor 3 with a predetermined torque (hereinafter referred to as "normal control") and a case where the operation of the power conversion circuit 1 is controlled so that the output of AC power from the power conversion circuit 1 to the induction motor 3 is cut off (hereinafter referred to as "cut-off control").
  • This switching of the calculation method can be performed, for example, based on the control command cmd input to the control device 2.
  • the switching contact 15 switches the excitation current command Idp2 output from the pattern generating unit 9.
  • the pattern generating unit 9 switches the switching contact 15 so that during normal control, it outputs the d-axis current command Idp1 input from the current command generating unit 8 as the excitation current command Idp2, and during cut-off control, it outputs the output of the adder 16 as the excitation current command Idp2.
  • Adder 16 adds the output of differential element 29 to d-axis current command Idp1. This added value is output from adder 16 via switching contact 15 as excitation current command Idp2 during cutoff control, as described above.
  • the switching contact 17 switches the d-axis current command hold value Idph.
  • the pattern generating unit 9 switches the switching contact 17 so that the d-axis current command Idp1 output from the current command generating unit 8 and input to the pattern generating unit 9 is the d-axis current command hold value Idph, and during cut-off control, the pattern generating unit 9 switches the switching contact 17 so that the output of the delay element 18 is the d-axis current command hold value Idph.
  • the delay element 18 delays the output of the switching contact 17 and outputs it.
  • the d-axis current command hold value Idph is successively updated according to the value of the d-axis current command Idp1 input from the current command generation unit 8 to the pattern generation unit 9.
  • the value of the d-axis current command Idp1 input from the current command generation unit 8 to the pattern generation unit 9 immediately before switching is held as the d-axis current command hold value Idph.
  • Subtractor 19 subtracts the output of integral element 21 from d-axis current command Idp1. This subtracted value is output to gain 20.
  • Gain 20 multiplies the output of subtractor 19 by the inverse of the preset secondary time constant T2 of induction motor 3. This multiplied value is output to integral element 21.
  • Integral element 21 accumulates the output of gain 20. This accumulated value is output to integral element 21, switching contact 22, and switching contact 24.
  • the switching contact 22 switches the magnetization current command I0 input to the gain 23.
  • the pattern generating unit 9 switches the switching contact 22 so that during normal control, the output of the integral element 21 is input to the gain 23 as the magnetization current command I0, and during cut-off control, the pattern generating unit 9 switches the switching contact 22 so that the output of the divider 27 is input to the gain 23 as the magnetization current command I0.
  • Gain 23 multiplies the magnetization current command I0 input from switching contact 22 by the preset excitation inductance L of induction motor 3. This multiplied value is output from pattern generator 9 as d-axis magnetic flux command ⁇ dp.
  • the switching contact 24 switches the magnetization current command holding value I0h.
  • the pattern generating unit 9 switches the switching contact 24 so that the output of the integral element 21 is the magnetization current command holding value I0h during normal control, and the output of the delay element 25 is the magnetization current command holding value I0h during cut-off control.
  • the delay element 25 delays the output of the switching contact 24 and outputs it.
  • the magnetization current command holding value I0h is successively updated according to the value of the magnetization current command I0 output from the integral element 21 and input to the gain 23.
  • the value of the magnetization current command I0 input to the gain 23 immediately before switching is held as the magnetization current command holding value I0h.
  • the multiplier 26 multiplies the d-axis current command Idp1 by the magnetization current command hold value I0h. This multiplied value is output to the divider 27.
  • the divider 27 divides the output of the multiplier 26 by the d-axis current command hold value Idph. This divided value is output to the switching contact 22 and the gain 28.
  • Gain 28 multiplies the output of divider 27 by a preset secondary time constant T2 of induction motor 3. This multiplied value is output to differential element 29.
  • the differential element 29 calculates the amount of change over time in the output of the gain 28. This calculated value is output to the adder 16.
  • the excitation current command Idp2 and magnetization current command I0 are obtained based on the d-axis current command Idp1 through the operation of each component as described above, and the d-axis magnetic flux command ⁇ dp can be generated based on the magnetization current command I0 and the excitation inductance L preset according to the characteristics of the induction motor 3.
  • the excitation current command Idp2 can be obtained from the d-axis current command Idp1
  • the magnetization current command I0 can be obtained based on the d-axis current command Idp1 and the secondary time constant T2 preset according to the characteristics of the induction motor 3.
  • the magnetization current command I0 can be obtained based on the d-axis current command Idp1, the magnetization current command hold value I0h, and the d-axis current command hold value Idph, and the excitation current command Idp2 can be obtained based on the magnetization current command I0 and the secondary time constant T2.
  • FIG. 4 shows an example of each command and state quantity when cutoff control is performed after the d-axis magnetic flux command ⁇ dp has been fully started. Note that FIG. 4 shows an example of the operation of a power conversion device when the control device 2 described in FIG. 2 and FIG. 3 is used as an application example of the present invention, but similar results can be obtained with a conventional control method to which the present invention is not applied.
  • the switching contacts 15, 17, 22, and 24 are each in the normal switching state. In the example of Figure 4, this state continues from the start of the rise of the d-axis current command Idp1 until it reaches a constant value and immediately before it is cut off.
  • the cut-off command is in the on state, i.e., while cut-off control is being performed, in the pattern generation unit 9, as described above, the switching contacts 15, 17, 22, and 24 are each in the cut-off switching state. In the example of Figure 4, this state continues from the fall of the d-axis current command Idp1 until it reaches zero.
  • the d-axis current command Idp1 is shown by a solid line
  • the magnetization current command I0 is shown by a dashed line superimposed on it.
  • the magnetization current command I0 acts as a first-order lag with a second-order time constant T2 relative to the d-axis current command Idp1 due to the operation of the subtractor 19, gain 20, integral element 21, and switching contact 22.
  • the d-axis current command Idp1 After the d-axis current command Idp1 finishes rising and reaches a constant value, when sufficient time has passed, the d-axis current command Idp1 and the magnetization current command I0 will match, as shown in Figure 4. Therefore, in the example of Figure 4, during the interruption control, the d-axis current command Idp1 and the magnetization current command I0 will be the same value due to the operation of the multiplier 26, the divider 27, and the switching contact 22.
  • the excitation current command Idp2 becomes the same value as the d-axis current command Idp1 during normal control, and during cut-off control, becomes the value obtained by multiplying the time rate of change of the magnetization current command I0 (dI0/dt) by the secondary time constant T2 and adding it to the d-axis current command Idp1.
  • the d-axis magnetic flux command ⁇ dp is the magnetization current command I0 multiplied by the excitation inductance L.
  • the steady-state value of the excitation current command Idp2 is defined as Idp0.
  • the value of the d-axis current command Idp1 coincides with the excitation current command Idp2 and the magnetization current command I0.
  • the value of the d-axis magnetic flux command ⁇ dp at this time is equal to the value obtained by multiplying the steady-state value Idp0 of the excitation current command Idp2 by the excitation inductance L.
  • the d-axis magnetic flux ⁇ d can be reduced to zero without undershooting the command value by the d-axis magnetic flux command ⁇ dp. This allows the d-axis magnetic flux ⁇ d to be attenuated without remaining when the power conversion circuit 1 is cut off.
  • Figure 5 is a diagram showing an example of each command and state quantity when cutoff control is performed before the rise of the d-axis magnetic flux command ⁇ dp is completed using a conventional control method. Unlike Figure 4, Figure 5 shows an example of an operation waveform in which the d-axis current command Idp1 falls after the d-axis magnetic flux command ⁇ dp starts to rise and before it reaches a constant value. Note that explanations of each command and state quantity in Figure 5 that behave in the same way as in Figure 4 will be omitted below.
  • the d-axis magnetic flux command ⁇ dp when the d-axis magnetic flux command ⁇ dp has completed rising and is at a constant value as shown in FIG. 4, the d-axis magnetic flux ⁇ d can be sufficiently attenuated when transitioning from normal control to cutoff control.
  • the d-axis magnetic flux command ⁇ dp becomes discontinuous as shown in FIG. 5, and an excessively large command value is output as the d-axis magnetic flux command ⁇ dp.
  • the d-axis magnetic flux ⁇ d crosses zero and undershoots, so that the d-axis magnetic flux ⁇ d remains inside the induction motor 3 even after the power conversion device is stopped. If the power conversion device is restarted in this state where the d-axis magnetic flux ⁇ d remains inside the induction motor 3, excessive current and torque will be generated. To prevent this, even if transitioning from normal control to cutoff control occurs during the rise of the d-axis magnetic flux command ⁇ dp, it is necessary that the d-axis magnetic flux command ⁇ dp does not become discontinuous and that the d-axis magnetic flux ⁇ d is attenuated at a constant rate of change until it reaches zero.
  • the power conversion device of this embodiment solves the above-mentioned problems and provides a means for sufficiently attenuating the magnetic flux of the induction motor 3 when the power conversion device is shut down.
  • the switching contact 17 and delay element 18 are used to hold the d-axis current command Idp1 immediately before switching from normal control to shut-down control as the d-axis current command hold value Idph
  • the switching contact 24 and delay element 25 are used to hold the magnetization current command I0 immediately before switching from normal control to shut-down control as the magnetization current command hold value I0h.
  • the multiplier 26 and divider 27 then multiply the d-axis current command Idp1 by the magnetization current command hold value I0h and divide the result by the d-axis current command hold value Idph to calculate the magnetization current command I0 during the shut-down control.
  • the d-axis current command Idp1 can be corrected by the ratio of the d-axis current command holding value Idph to the magnetization current command holding value I0h immediately before that.
  • the magnetization current command I0 can be made a continuous value, and the magnetization current command I0 can be used to calculate the d-axis flux command ⁇ dp, which decreases continuously.
  • the d-axis flux ⁇ d is attenuated at a constant rate of change until it reaches zero, preventing the d-axis flux ⁇ d from remaining inside the induction motor 3.
  • the d-axis magnetic flux command ⁇ dp is calculated based on the corrected value of the d-axis current command Idp1. Therefore, during the fall time of the d-axis current command Idp1 (d-axis current command fall time Td), the d-axis magnetic flux command ⁇ dp can be fallen at a constant rate of change from just before interruption to zero.
  • FIG. 6 is a diagram showing an example of each command and state quantity when cutoff control is performed before the start-up of the d-axis magnetic flux command ⁇ dp is completed in the power conversion device according to the first embodiment of the present invention. Note that in FIG. 6, the commands and state quantities that behave in the same way as in FIG. 4 will not be described below.
  • the value of the excitation current command Idp2 during interruption control is calculated by multiplying the time rate of change of the magnetization current command I0 (dI0/dt) by the secondary time constant T2 of the induction motor 3 and adding this to the d-axis current command Idp1. Since the magnetization current command I0 decreases at a constant rate of change, the value of the excitation current command Idp2 at this time is the value obtained by translating the d-axis current command Idp1 in the negative direction.
  • the actual d-axis magnetic flux ⁇ d in the induction motor 3 can be lowered at a constant rate of change.
  • the d-axis magnetic flux ⁇ d can be attenuated to zero without undershooting.
  • the residual amount of the d-axis magnetic flux ⁇ d when the power conversion device is cut off can be made zero. Therefore, the generation of excessive current and torque when the power conversion device is restarted can be suppressed.
  • the first embodiment of the present invention described above provides the following effects.
  • the power conversion device includes a power conversion circuit 1 that converts DC power into AC power to drive an induction motor 3, and a control device 2 that outputs gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 to the power conversion circuit 1 to control the power conversion circuit 1.
  • the control device 2 determines the d-axis current command Idp1, the excitation current command Idp2, and the d-axis flux command ⁇ dp used to generate the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2, and is capable of holding a magnetization current command holding value I0h and a d-axis current command holding value Idph according to the value of the d-axis flux command ⁇ dp immediately before the d-axis current command Idp1 starts to fall, and determines the d-axis current command Idp1, the excitation current command Idp2, and the d-axis flux command ⁇ dp based on these held values when the power conversion circuit 1 is shut off. This allows the residual magnetic flux inside the induction motor 3 to be sufficiently attenuated even if the power conversion device is shut off while the d-axis magnetic flux command ⁇ dp is rising.
  • a control command cmd for operating or stopping the power conversion circuit 1 is input to the control device 2. Based on the control command cmd, the control device 2 performs either normal control for the period before the d-axis current command Idp1 starts to fall, or interruption control for the period after the d-axis current command Idp1 starts to fall, and is capable of holding a holding value corresponding to the value of the d-axis magnetic flux command ⁇ dp immediately before switching from normal control to interruption control.
  • the control device 2 has a current command generating unit 8 that generates a d-axis current command Idp1 and a q-axis current command Iqp according to the control command cmd, a pattern generating unit 9 that determines an excitation current command Idp2 and a magnetization current command I0 based on the d-axis current command Idp1 and generates a d-axis magnetic flux command ⁇ dp based on the magnetization current command I0 and an excitation inductance L that is preset according to the characteristics of the induction motor 3, a voltage command generating unit 13 that generates a voltage command based on the excitation current command Idp2, the d-axis magnetic flux command ⁇ dp, and the q-axis current command Iqp, and a pulse command generating unit 14 that generates gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, Sw2 based on the voltage command.
  • the pattern generating unit 9 holds the value of the magnetization current command I0 immediately before switching from the normal control to the cutoff control as a magnetization current command holding value I0h. By doing this, when the power conversion device is shut off during the rise of the d-axis magnetic flux command ⁇ dp, gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 can be generated that can sufficiently attenuate the residual magnetic flux inside the induction motor 3.
  • the pattern generator 9 uses the switch contact 15 to determine the excitation current command Idp2 from the d-axis current command Idp1, and uses the subtractor 19, gain 20, integral element 21, and switch contact 22 to determine the magnetization current command I0 based on the d-axis current command Idp1 and a secondary time constant T2 preset according to the characteristics of the induction motor 3.
  • the pattern generator 9 uses the switch contact 24, delay element 25, multiplier 26, and divider 27 to determine the magnetization current command I0 based on the d-axis current command Idp1, the magnetization current command hold value I0h, and the d-axis current command hold value Idph, and uses the gain 28, differential element 29, and adder 16 to determine the excitation current command Idp2 based on the magnetization current command I0 and the secondary time constant T2.
  • the values of the excitation current command Idp2 and magnetization current command I0 required to generate the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 can be appropriately determined in both normal control and interruption control.
  • the pattern generation unit 9 continues to hold the magnetization current command hold value I0h and the d-axis current command hold value Idph. Specifically, the pattern generation unit 9 holds the value of the magnetization current command I0 and the value of the excitation current command Idp2 immediately before switching from normal control to interruption control as the magnetization current command hold value I0h and the d-axis current command hold value Idph, respectively, using the switching contact 24 and delay element 25, and the switching contact 17 and delay element 18.
  • the multiplier 26 and divider 27 divide the product of the d-axis current command Idp1 and the magnetization current command hold value I0h by the d-axis current command hold value Idph to obtain the value of the magnetization current command I0 during the interruption control. In this way, even if the control transitions to the interruption control during the rise of the d-axis magnetic flux command ⁇ dp, the value of the magnetization current command I0, which changes continuously, can be calculated. As a result, the d-axis magnetic flux ⁇ d is attenuated at a constant rate until it reaches zero, and the d-axis magnetic flux ⁇ d is reliably prevented from remaining inside the induction motor 3.
  • the power conversion device of this embodiment has a similar configuration to the power conversion device of FIG. 1 described in the first embodiment, but the functional configuration of the control device 2 is different.
  • FIG. 7 is a functional block diagram showing details of a control device 2 according to a second embodiment of the present invention.
  • the pattern generator 9 is replaced with a pattern generator 9A, and in addition to the d-axis current command Idp1, the current command generator 8 outputs the d-axis current command fall time Td to the pattern generator 9A.
  • the pattern generator 9A uses the d-axis current command fall time Td to calculate the magnetization current command I0 and the d-axis magnetic flux command ⁇ dp at the time of interruption.
  • FIG. 8 is a control block diagram showing details of a pattern generator 9A according to a second embodiment of the present invention.
  • the pattern generator 9A of this embodiment adds an input of the d-axis current command fall time Td, and is configured with a divider 30, gain 31, and switch contact 32 instead of the switch contact 17, delay element 18, switch contact 22, multiplier 26, divider 27, and differential element 29 in the pattern generator 9 of FIG. 3 described in the first embodiment.
  • the divider 30 divides the magnetization current command holding value I0h by the d-axis current command falling time Td. This divided value is output to the gain 31.
  • Gain 31 inverts the output of divider 30 by multiplying it by -1, and outputs it to gain 28 and switching contact 32.
  • the differential element 29 is not provided on the output side of the gain 28. Therefore, the gain 28 multiplies the output of the divider 30, the sign of which has been inverted by the gain 31, by the secondary time constant T2 of the induction motor 3, and outputs the result to the adder 16.
  • the switching contact 32 switches the value input to the integral element 21.
  • the pattern generating unit 9A switches the switching contact 32 so that the output of the gain 20 is input to the integral element 21 during normal control, and the output of the gain 31 is input to the integral element 21 during cutoff control.
  • the d-axis current command fall time Td is used instead of the d-axis current command holding value Idph described in the first embodiment to calculate the excitation current command Idp2 and magnetization current command I0 at the time of cutoff, and the d-axis magnetic flux command ⁇ dp is obtained.
  • the pattern generator 9A also uses the gain 31 to invert the sign of the value obtained by dividing the magnetization current command holding value I0h by the d-axis current command fall time Td. This process corresponds to the calculation of the time rate of change of the magnetization current command I0 performed by the differential element 29 in the first embodiment. In other words, in this embodiment, the excitation current command Idp2 at the time of interruption can be obtained without using the differential element 29.
  • the integral element 21 is configured to integrate the ratio of the d-axis current command fall time Td to the magnetization current command holding value I0h during interruption control, the integral element 21 can be shared between normal operation and interruption. Therefore, it is possible to reliably guarantee the continuity of the d-axis magnetic flux command ⁇ dp when transitioning from normal operation control to interruption control.
  • the magnetization current command I0 that decreases at a constant rate when the current is cut off is calculated based on the ratio of the d-axis current command fall time Td to the magnetization current command hold value I0h, but this embodiment does not need to be limited to this configuration.
  • the input to the rate of change limiter is set to a value obtained by subtracting the magnetization current command I0 from zero, and the output is limited by the ratio of the d-axis current command fall time Td to the magnetization current command hold value I0h, thereby realizing a magnetization current command I0 that decreases at a constant rate.
  • the d-axis magnetic flux command ⁇ dp when the state transition occurs from normal control to cut-off control during the rise of the d-axis magnetic flux command ⁇ dp, the d-axis magnetic flux command ⁇ dp can be lowered continuously and at a constant rate, so that the d-axis magnetic flux ⁇ d can be attenuated to zero without undershooting. In other words, the residual amount of the d-axis magnetic flux ⁇ d when the power conversion device is cut off can be made zero. This makes it possible to suppress the generation of excessive current and torque when the power conversion device is restarted.
  • the differential element 29 described in the first embodiment is not necessary, so even if the d-axis current command Idp1 suddenly changes due to the influence of a disturbance at the time of interruption, the excitation current command Idp2 does not diverge, and the power conversion device can operate stably.
  • the pattern generating unit 9A continues to hold the magnetization current command holding value I0h after switching from normal control to interruption control. Specifically, the current command generating unit 8 outputs the d-axis current command falling time Td, which represents the time from the start to the end of the fall of the d-axis current command Idp1.
  • the pattern generating unit 9A holds the value of the magnetization current command I0 immediately before switching from normal control to interruption control as the magnetization current command holding value I0h using the switching contact 24 and delay element 25.
  • the divider 30, gain 31, and integral element 21 calculate the value obtained by dividing the magnetization current command holding value I0h by the d-axis current command falling time Td, and then inverting the sign of the value to obtain the value of the magnetization current command I0 during the interruption control.
  • the value of the magnetization current command I0 which changes continuously, can be calculated.
  • the d-axis magnetic flux ⁇ d is attenuated at a constant rate until it reaches zero, and the d-axis magnetic flux ⁇ d is reliably prevented from remaining inside the induction motor 3.
  • FIG. 9 is a control block diagram showing details of a pattern generator 9B according to a third embodiment of the present invention.
  • the pattern generator 9B of this embodiment is configured with a switch contact 32, a minimum limiter 33, and a gain 34, instead of the switch contact 17, delay element 18, switch contact 22, switch contact 24, delay element 25, multiplier 26, divider 27, and differential element 29 in the pattern generator 9 of FIG. 3 described in the first embodiment.
  • the minimum value limiter 33 limits the output from the subtractor 19 to an upper limit value of 0 and outputs it to the gain 34. In other words, if the magnitude of the difference between the d-axis current command Idp1 and the magnetization current command I0 calculated by the subtractor 19 is a negative value, the value is output as is to the gain 34, and if it is a positive value, the upper limit value of 0 is output to the gain 34.
  • Gain 34 multiplies the output of minimum limiter 33 by the inverse of the preset primary time constant T ⁇ of induction motor 3. This multiplied value is output from gain 34 to switching contact 32 and gain 28.
  • the differential element 29 is not provided on the output side of the gain 28. Therefore, the gain 28 is limited to a range equal to or less than the upper limit value 0 by the minimum value limiter 33, and the difference between the d-axis current command Idp1 and the magnetization current command I0 multiplied by the reciprocal of the primary time constant T ⁇ by the gain 34 is multiplied by the secondary time constant T2 of the induction motor 3 and output to the adder 16.
  • the switching contact 32 switches the value input to the integral element 21.
  • the pattern generating unit 9B switches the switching contact 32 so that the output of the gain 20 is input to the integral element 21 during normal control, and the output of the gain 34 is input to the integral element 21 during cut-off control.
  • the excitation current command Idp2 and magnetization current command I0 during cut-off are calculated using the primary time constant T ⁇ instead of the d-axis current command holding value Idph described in the first embodiment, and the d-axis magnetic flux command ⁇ dp is obtained.
  • the pattern generating unit 9B of this embodiment normally operates as a first-order lag with the secondary time constant T2 as a time constant, as in the first embodiment, through the subtractor 19, gain 20, and integral element 21 via the switching contact 32.
  • the time constant during cut-off only needs to be sufficiently short compared to the secondary time constant T2, so it is not limited to the primary time constant T ⁇ of the induction motor 3, and other time constants may be used.
  • the time constant of the first-order lag element is switched from the second-order time constant T2 to the first-order time constant T ⁇ .
  • the first-order time constant T ⁇ is sufficiently short compared to the second-order time constant T2
  • the fall rate and fall time of the d-axis flux command ⁇ dp at the time of interruption almost match the d-axis current command Idp1.
  • the integral element 21 that constitutes the first-order lag element maintains the continuity of the d-axis flux command ⁇ dp. Therefore, even if the state transition occurs from normal control to interruption control during the rise of the d-axis flux command ⁇ dp, the d-axis flux command ⁇ dp can be continuously fallen at a constant rate.
  • the output of the gain 34 is multiplied by the secondary time constant T2 using the gain 28 and the adder 16, and the result is added to the d-axis current command Idp1 to obtain the excitation current command Idp2 at the time of interruption. Since the output of the gain 34 is equal to the time rate of change of the magnetization current command I0, this makes it possible to calculate the excitation current command Idp2 required for the continuous operation of the d-axis magnetic flux command ⁇ dp.
  • the interrupt control starts in a state where the d-axis current command Idp1 is greater than the magnetization current command I0. If the minimum value limiter 33 does not exist in the configuration of the pattern generator 9B shown in FIG. 9, the subtractor 19, gain 34, and integral element 21 are configured as first-order lag elements, so that the output of the subtractor 19 becomes positive even though the d-axis current command Idp1 decreases. As a result, the magnetization current command I0 operates largely in the positive direction, which is the opposite direction to the d-axis current command Idp1.
  • a minimum value limiter 33 is provided in front of the gain 34, which limits the output of the subtractor 19 to a negative value less than zero and inputs it to the gain 34.
  • FIG. 10 is a diagram showing an example of each command and state quantity when cutoff control is performed before the start-up of the d-axis magnetic flux command ⁇ dp is completed in a power conversion device according to a third embodiment of the present invention. Note that in FIG. 10, the commands and state quantities that behave in the same way as in FIG. 4 will not be described below.
  • the d-axis flux command ⁇ dp does not become discontinuous as shown in FIG. 10.
  • the time constant of the primary lag element from the secondary time constant T2 to the primary time constant T ⁇ , the increase in the d-axis flux command ⁇ dp at cutoff can be suppressed.
  • the d-axis flux command ⁇ dp is output at a constant value, and in the period after the d-axis current command Idp1 matches the magnetization current command I0, the d-axis flux command ⁇ dp decreases at a constant rate of change. This makes it possible to decrease the d-axis flux command ⁇ dp all the way to zero within the d-axis current command fall time Td.
  • the actual d-axis magnetic flux ⁇ d in the induction motor 3 can be continuously lowered at a constant rate of change, so the d-axis magnetic flux ⁇ d can be attenuated to zero without undershooting.
  • the residual amount of d-axis magnetic flux ⁇ d can be made zero when the power conversion device is cut off and the drive of the induction motor 3 is stopped. This makes it possible to suppress the generation of excessive current and torque when the power conversion device is restarted.
  • the pattern generating unit 9B uses the integral element 21, which is an integrator, to hold a holding value corresponding to the value of the d-axis magnetic flux command ⁇ dp immediately before the start of the fall of the d-axis current command Idp1. Specifically, the pattern generating unit 9B uses the subtractor 19 to obtain the difference between the d-axis current command Idp1 and the output of the integral element 21.
  • the gain 20 and the switching contact 32 obtain the output of the integral element 21 when the product of the difference and the reciprocal of the secondary time constant T2 is input to the integral element 21 as the magnetization current command I0
  • the gain 34 and the switching contact 32 obtain the output of the integral element 21 when the product of the difference and the reciprocal of the primary time constant T ⁇ , which is shorter than the secondary time constant T2, is input to the integral element 21 as the magnetization current command I0.
  • the pattern generating unit 9B has a minimum value limiter 33 that limits the input of the integral element 21 to a range of 0 or less during cutoff control.
  • the value of the magnetization current command I0 which changes continuously, can be calculated.
  • the d-axis magnetic flux ⁇ d is attenuated at a constant rate of change until it reaches zero, and the d-axis magnetic flux ⁇ d can be reliably prevented from remaining inside the induction motor 3.
  • the present invention is not limited to the above-described embodiments and modifications, and can be implemented using any components without departing from the spirit of the invention.
  • Each embodiment and modification may be used alone, or multiple embodiments and modifications may be used in any combination.
  • the present invention can achieve the above-described effects by combining the features of each embodiment in any combination.
  • 1...power conversion circuit 2...control device, 3...induction motor, 4...smoothing capacitor, 5a...U-phase upper arm element, 5b...U-phase lower arm element, 5c...V-phase upper arm element, 5d...V-phase lower arm element, 5e...W-phase upper arm element, 5f...W-phase lower arm element, 6...DC voltage sensor, 7a...U-phase current sensor, 7b...V-phase current sensor, 7c...W-phase current sensor, 8...current command generation unit, 9, 9A, 9B...pattern generation unit, 10...coordinate conversion unit, 1 1...rotation speed estimation unit, 12...frequency command generation unit, 13...voltage command generation unit, 14...pulse command generation unit, 15...switching contact, 16...adder, 17...switching contact, 18...delay element, 19...subtractor, 20...gain, 21...integral element, 22...switching contact, 23...gain, 24...switching contact, 25...delay element, 26...multiplier, 27...divider, 28...gain

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Abstract

This power converter comprises: a power converter circuit that converts direct-current power to alternating-current power to drive an induction motor; and a controller that outputs a gate pulse signal to the power converter circuit to control the power converter circuit. The controller can determine a current command and a magnetic flux command that are used for generating the gate pulse signal, and hold a hold value corresponding to the value of the magnetic flux command immediately before the start of falling of the current command. When interrupting the power converter, the controller determines the current command and the magnetic flux command on the basis of the hold value.

Description

電力変換装置、電力変換回路の制御方法Power conversion device and method for controlling power conversion circuit
　本発明は、電力変換装置および電力変換回路の制御方法に関する。 The present invention relates to a power conversion device and a method for controlling a power conversion circuit.
　従来、鉄道車両では、電力変換装置を用いて交流電動機を可変速駆動する駆動方式が広く用いられている。また、多くの鉄道車両では、車両の駆動に誘導電動機が用いられており、１台の電力変換装置で複数台の誘導電動機を一括駆動する方式が広く一般的に採用されている。 Traditionally, a driving method that uses a power conversion device to drive an AC motor at a variable speed has been widely used for railway vehicles. In addition, induction motors are used to drive the vehicle in many railway vehicles, and a method of collectively driving multiple induction motors with a single power conversion device is widely and commonly adopted.
　鉄道車両の運転では、停止状態から電力変換装置を起動して加速した後、電力変換装置を停止して惰性で走行する惰行状態となり、この状態から電力変換装置を再起動して加速または減速する運転操作が頻繁に行われる。鉄道車両が惰行状態になると、誘導電動機に電圧が印加されない状態となるが、電力変換装置が停止してから暫くの間は、誘導電動機の内部に電流が流れ続ける。この電流は、誘導電動機の内部抵抗により消費されて次第に減衰していくが、電流が消滅するまでの間は磁束が発生し続けるため、誘導電動機の内部に残留磁束が存在する。この残留磁束が大きい状態で電力変換装置を再起動すると、過大な電流の発生による電力変換装置の破壊や、過大なトルクの発生による車両の乗り心地の悪化などの悪影響が生じるおそれがある。 When operating railway vehicles, the power conversion device is started from a stopped state, the vehicle accelerates, the power conversion device is stopped, the vehicle enters a coasting state where the vehicle runs by inertia, and from this state the power conversion device is restarted and the vehicle is accelerated or decelerated. This is a common operation. When a railway vehicle enters a coasting state, no voltage is applied to the induction motor, but current continues to flow inside the induction motor for a while after the power conversion device is stopped. This current is consumed by the internal resistance of the induction motor and gradually decays, but magnetic flux continues to be generated until the current disappears, so residual magnetic flux exists inside the induction motor. If the power conversion device is restarted when this residual magnetic flux is large, adverse effects such as damage to the power conversion device due to the generation of excessive current and deterioration of the vehicle's ride comfort due to the generation of excessive torque may occur.
　上述の問題の対策として、例えば特許文献１に記載の技術が知られている。特許文献１には、誘導電動機を停止させる際に十分に磁束を減衰させる機能を有する電力変換装置の制御装置として、電流指令に基づいて電圧指令を生成する電圧演算部と、前記電圧指令に基づいて電力変換回路のゲートパルス信号を出力するＰＷＭ演算部を有し、励磁電流指令の立ち下げからゼロに至るまでの遮断時に、励磁電流指令の時間変化量に応じて算出した操作量を励磁電流指令に加算して遮断時励磁電流指令とし、この遮断時励磁電流指令を電圧演算部に対する電流指令とすることで、電力変換回路を停止するときに誘導電動機内部の残留磁束を減衰させるものが開示されている。 As a countermeasure to the above problem, for example, the technology described in Patent Document 1 is known. Patent Document 1 discloses a control device for a power conversion device that has the function of sufficiently attenuating magnetic flux when stopping an induction motor, and includes a voltage calculation unit that generates a voltage command based on a current command, and a PWM calculation unit that outputs a gate pulse signal for the power conversion circuit based on the voltage command. When the excitation current command is cut off from the falling edge to zero, an operation amount calculated according to the amount of change over time in the excitation current command is added to the excitation current command to obtain an excitation current command at the time of cut off, and this excitation current command at the time of cut off is used as a current command for the voltage calculation unit, thereby attenuating the residual magnetic flux inside the induction motor when the power conversion circuit is stopped.
日本国特開２０１７－７７０７９号公報Japanese Patent Publication No. 2017-77079
　特許文献１に記載の技術では、磁束指令を立ち上げる途中で電力変換装置を遮断する場合の制御について考慮されていない。そのため、このような場合には誘導電動機内部の残留磁束を十分に減衰できないおそれがある。 The technology described in Patent Document 1 does not take into consideration the control required when the power conversion device is shut off during the ramp-up of the magnetic flux command. As a result, in such a case, there is a risk that the residual magnetic flux inside the induction motor will not be sufficiently attenuated.
　本発明による電力変換装置は、直流電力を交流電力に変換して誘導電動機を駆動する電力変換回路と、前記電力変換回路にゲートパルス信号を出力して前記電力変換回路を制御する制御装置と、を備えたものであって、前記制御装置は、前記ゲートパルス信号の生成に用いられる電流指令および磁束指令を求めるとともに、前記電流指令の立ち下げ開始直前における前記磁束指令の値に応じた保持値を保持可能であり、前記電力変換回路を遮断する際には、前記保持値に基づいて前記電流指令および前記磁束指令を求める。
　本発明による電力変換回路の制御方法は、直流電力を交流電力に変換して誘導電動機を駆動する電力変換回路の制御方法であって、電流指令および磁束指令を求め、前記電流指令および前記磁束指令に基づいてゲートパルス信号を生成し、前記ゲートパルス信号を前記電力変換回路へ出力し、前記電流指令の立ち下げ開始直前における前記磁束指令の値に応じた保持値を保持し、前記電力変換回路を遮断する際には、前記保持値に基づいて前記電流指令および前記磁束指令を求める。 A power conversion device according to the present invention includes a power conversion circuit that converts DC power to AC power to drive an induction motor, and a control device that outputs a gate pulse signal to the power conversion circuit to control the power conversion circuit, wherein the control device determines a current command and a magnetic flux command used in generating the gate pulse signal, and is capable of holding a hold value corresponding to the value of the magnetic flux command immediately before the current command starts to fall, and when shutting off the power conversion circuit, determines the current command and the magnetic flux command based on the held value.
A control method for a power conversion circuit according to the present invention is a control method for a power conversion circuit that converts DC power to AC power to drive an induction motor, the control method comprising the steps of: determining a current command and a magnetic flux command; generating a gate pulse signal based on the current command and the magnetic flux command; outputting the gate pulse signal to the power conversion circuit; holding a hold value corresponding to the value of the magnetic flux command immediately before the current command starts to fall; and, when shutting off the power conversion circuit, determining the current command and the magnetic flux command based on the held value.
　本発明によれば、磁束指令を立ち上げる途中で電力変換装置を遮断する場合でも、誘導電動機内部の残留磁束を十分に減衰できる。 According to the present invention, even if the power conversion device is shut off during the start-up of the magnetic flux command, the residual magnetic flux inside the induction motor can be sufficiently attenuated.
本発明の一実施形態に係る電力変換装置の構成を示す図である。1 is a diagram showing a configuration of a power conversion device according to an embodiment of the present invention; 本発明の第１の実施形態に係る制御装置の詳細を示す機能ブロック図である。FIG. 2 is a functional block diagram showing details of a control device according to the first embodiment of the present invention. 本発明の第１の実施形態に係るパタン生成部の詳細を示す制御ブロック図である。FIG. 2 is a control block diagram showing details of a pattern generating unit according to the first embodiment of the present invention. ｄ軸磁束指令の立ち上げ完了後に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。11 is a diagram showing an example of each command and state quantity when cut-off control is performed after completion of the rise of the d-axis magnetic flux command. FIG. 従来の制御方法によりｄ軸磁束指令の立ち上げ完了前に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。1 is a diagram showing an example of each command and state quantity when cutoff control is performed before the start-up of a d-axis magnetic flux command is completed by a conventional control method. FIG. 本発明の第１の実施形態に係る電力変換装置において、ｄ軸磁束指令の立ち上げ完了前に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。4 is a diagram showing an example of each command and a state quantity in a case where cutoff control is performed before the start-up of a d-axis magnetic flux command is completed in the power conversion device according to the first embodiment of the present invention. FIG. 本発明の第２の実施形態に係る制御装置の詳細を示す機能ブロック図である。FIG. 11 is a functional block diagram showing details of a control device according to a second embodiment of the present invention. 本発明の第２の実施形態に係るパタン生成部の詳細を示す制御ブロック図である。FIG. 11 is a control block diagram showing details of a pattern generating unit according to a second embodiment of the present invention. 本発明の第３の実施形態に係るパタン生成部の詳細を示す制御ブロック図である。FIG. 13 is a control block diagram showing details of a pattern generating unit according to a third embodiment of the present invention. 本発明の第３の実施形態に係る電力変換装置において、ｄ軸磁束指令の立ち上げ完了前に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。FIG. 11 is a diagram showing an example of each command and a state quantity in a case where cutoff control is performed before the start-up of a d-axis magnetic flux command is completed in a power conversion device according to a third embodiment of the present invention.
　以下、図面を参照しながら、本発明の実施形態に係る電力変換装置を説明する。以下の各実施形態では鉄道車両の用途を例に説明するが、例えば一般産業用途などの他の用途にも適用可能である。 Below, a power conversion device according to an embodiment of the present invention will be described with reference to the drawings. In each of the following embodiments, the application to a railway vehicle will be described as an example, but the device can also be applied to other applications, such as general industrial applications.
（第１の実施形態）
　図１は、本発明の一実施形態に係る電力変換装置の構成を示す図である。図１に示す電力変換装置は、誘導電動機３と接続されており、外部の直流電源から供給される直流電力を交流電力に変換して誘導電動機３に出力することで誘導電動機３を駆動する電力変換回路１と、電力変換回路１を制御する制御装置２とを備える。 First Embodiment
Fig. 1 is a diagram showing the configuration of a power conversion device according to an embodiment of the present invention. The power conversion device shown in Fig. 1 includes a power conversion circuit 1 that is connected to an induction motor 3 and converts DC power supplied from an external DC power source into AC power and outputs the AC power to the induction motor 3 to drive the induction motor 3, and a control device 2 that controls the power conversion circuit 1.
　電力変換回路１は、半導体スイッチング素子であるＵ相上アーム素子５ａ、Ｕ相下アーム素子５ｂ、Ｖ相上アーム素子５ｃ、Ｖ相下アーム素子５ｄ、Ｗ相上アーム素子５ｅおよびＷ相下アーム素子５ｆを有する。Ｕ相上アーム素子５ａとＵ相下アーム素子５ｂ、Ｖ相上アーム素子５ｃとＶ相下アーム素子５ｄ、Ｗ相上アーム素子５ｅとＷ相下アーム素子５ｆは、電力変換回路１においてそれぞれ直列に接続されることで、Ｕ相、Ｖ相、Ｗ相の各相の上下アーム回路を形成している。これらの各上下アーム回路の上アーム素子５ａ，５ｃ，５ｅと下アーム素子５ｂ，５ｄ，５ｆの間には、誘導電動機３に繋がる電力線がそれぞれ接続される。 The power conversion circuit 1 has a U-phase upper arm element 5a, a U-phase lower arm element 5b, a V-phase upper arm element 5c, a V-phase lower arm element 5d, a W-phase upper arm element 5e, and a W-phase lower arm element 5f, which are semiconductor switching elements. The U-phase upper arm element 5a and the U-phase lower arm element 5b, the V-phase upper arm element 5c and the V-phase lower arm element 5d, and the W-phase upper arm element 5e and the W-phase lower arm element 5f are connected in series in the power conversion circuit 1, forming upper and lower arm circuits for the U, V, and W phases. Power lines leading to the induction motor 3 are connected between the upper arm elements 5a, 5c, 5e and the lower arm elements 5b, 5d, 5f of each of these upper and lower arm circuits.
　電力変換回路１は、制御装置２から出力されるゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２に応じて半導体スイッチング素子５ａ～５ｆがそれぞれスイッチング駆動することにより、直流電源から供給される直流電力を三相交流電力に変換する。この変換後の三相交流電力が各相の電力線を介して電力変換回路１から誘導電動機３へ出力されることで、本実施形態の電力変換装置による誘導電動機３の駆動制御が行われる。 The power conversion circuit 1 converts DC power supplied from a DC power source into three-phase AC power by switching and driving the semiconductor switching elements 5a to 5f in response to the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 output from the control device 2. The converted three-phase AC power is output from the power conversion circuit 1 to the induction motor 3 via the power lines of each phase, thereby controlling the drive of the induction motor 3 by the power conversion device of this embodiment.
　直流電源から供給される直流電力は、平滑化コンデンサ４により平滑化されて電力変換回路１に入力される。平滑化コンデンサ４の端子間電圧、すなわち電力変換回路１に入力される直流電力の電圧Ｅｃｆは、直流電圧センサ６により検出され、その検出値が制御装置２に入力される。 The DC power supplied from the DC power source is smoothed by the smoothing capacitor 4 and input to the power conversion circuit 1. The terminal voltage of the smoothing capacitor 4, i.e., the voltage Ecf of the DC power input to the power conversion circuit 1, is detected by the DC voltage sensor 6, and the detected value is input to the control device 2.
　電力変換回路１と誘導電動機３の間に設けられた各相の電力線には、誘導電動機３に流れるＵ相電流ｉｕ、Ｖ相電流ｉｖ、Ｗ相電流ｉｗをそれぞれ検出するＵ相電流センサ７ａ、Ｖ相電流センサ７ｂ、Ｗ相電流センサ７ｃが設置される。これらの電流センサ７ａ～７ｃによる各相電流の検出結果は、制御装置２に入力される。 　A U-phase current sensor 7a, a V-phase current sensor 7b, and a W-phase current sensor 7c are installed on the power lines of each phase between the power conversion circuit 1 and the induction motor 3 to detect the U-phase current iu, the V-phase current iv, and the W-phase current iw that flow through the induction motor 3. The detection results of each phase current by these current sensors 7a to 7c are input to the control device 2.
　制御装置２は、直流電圧センサ６による直流電圧Ｅｃｆの検出値と、電流センサ７ａ～７ｃによるＵ相電流ｉｕ、Ｖ相電流ｉｖ、Ｗ相電流ｉｗの検出値とに基づき、ゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２を生成し、電力変換回路１へ出力する。 The control device 2 generates gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 based on the detection value of the DC voltage Ecf by the DC voltage sensor 6 and the detection values of the U-phase current iu, V-phase current iv, and W-phase current iw by the current sensors 7a to 7c, and outputs them to the power conversion circuit 1.
　図２は、本発明の第１の実施形態に係る制御装置２の詳細を示す機能ブロック図である。制御装置２は、電流指令生成部８、パタン生成部９、座標変換部１０、回転速度推定部１１、周波数指令生成部１２、電圧指令生成部１３およびパルス指令生成部１４の各機能ブロックを有する。制御装置２は、例えばＣＰＵやメモリ等を有するマイクロコンピュータを用いて構成され、ＣＰＵにおいて所定のプログラムを実行することにより、図２の各機能ブロックに対応する機能を実現することができる。なお、制御装置２の機能の一部または全部を、ＦＰＧＡ（Field Programmable Gate Array）等のロジック回路を用いて実現してもよい。 FIG. 2 is a functional block diagram showing details of the control device 2 according to the first embodiment of the present invention. The control device 2 has the following functional blocks: a current command generation unit 8, a pattern generation unit 9, a coordinate conversion unit 10, a rotational speed estimation unit 11, a frequency command generation unit 12, a voltage command generation unit 13, and a pulse command generation unit 14. The control device 2 is configured using, for example, a microcomputer having a CPU, memory, etc., and can realize functions corresponding to each functional block in FIG. 2 by executing a predetermined program in the CPU. Note that some or all of the functions of the control device 2 may be realized using a logic circuit such as an FPGA (Field Programmable Gate Array).
　制御装置２には、電力変換回路１を運転または停止させる制御指令ｃｍｄが外部より入力される。電流指令生成部８は、制御指令ｃｍｄに応じたｄ軸電流指令Ｉｄｐ１およびｑ軸電流指令Ｉｑｐを生成して出力する。電流指令生成部８は、例えば、電力変換回路１を運転させる制御指令ｃｍｄが入力されているときには、所定のトルクで誘導電動機３を駆動するのに必要な交流電力が電力変換回路１から出力されるように、ｄ軸電流指令Ｉｄｐ１およびｑ軸電流指令Ｉｑｐを生成する。 The control device 2 receives a control command cmd from the outside to operate or stop the power conversion circuit 1. The current command generation unit 8 generates and outputs a d-axis current command Idp1 and a q-axis current command Iqp according to the control command cmd. For example, when a control command cmd to operate the power conversion circuit 1 is input, the current command generation unit 8 generates a d-axis current command Idp1 and a q-axis current command Iqp so that the AC power required to drive the induction motor 3 with a specified torque is output from the power conversion circuit 1.
　パタン生成部９は、電流指令生成部８から入力されるｄ軸電流指令Ｉｄｐ１に基づいて励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐを演算し、電圧指令生成部１３に出力する。励磁電流指令Ｉｄｐ２とは、誘導電動機３の回転磁界の方向であるｄ軸方向の電流に対する指令値であり、電力変換回路１の通常運転時にはｄ軸電流指令Ｉｄｐ１に等しく、電力変換回路１を停止させるときには、誘導電動機３の磁束を減衰させるためにｄ軸電流指令Ｉｄｐ１を補正した補正値に相当するものである。なお、パタン生成部９は、誘導電動機３の制御状態に応じて、励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐの演算方法をそれぞれ切り替える。パタン生成部９による励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐの演算方法の詳細については後述する。 The pattern generation unit 9 calculates the excitation current command Idp2 and the d-axis magnetic flux command φdp based on the d-axis current command Idp1 input from the current command generation unit 8, and outputs them to the voltage command generation unit 13. The excitation current command Idp2 is a command value for the current in the d-axis direction, which is the direction of the rotating magnetic field of the induction motor 3. It is equal to the d-axis current command Idp1 during normal operation of the power conversion circuit 1, and corresponds to a corrected value obtained by correcting the d-axis current command Idp1 to attenuate the magnetic flux of the induction motor 3 when the power conversion circuit 1 is stopped. The pattern generation unit 9 switches the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command φdp depending on the control state of the induction motor 3. The calculation method of the excitation current command Idp2 and the d-axis magnetic flux command φdp by the pattern generation unit 9 will be described in detail later.
　座標変換部１０は、電流センサ７ａ～７ｃによりそれぞれ検出されたＵ相電流ｉｕ、Ｖ相電流ｉｖおよびＷ相電流ｉｗに対して回転座標変換を行うことにより、ｄ軸電流検出値Ｉｄｆおよびｑ軸電流検出値Ｉｑｆを求め、これらの電流検出値を回転速度推定部１１に出力する。なお、座標変換部１０では、誘導電動機３の回転磁界の方向をｄ軸方向とし、トルクを発生させるために流す電流の方向をｑ軸方向として、ｄ軸電流検出値Ｉｄｆおよびｑ軸電流検出値Ｉｑｆを求める。 The coordinate conversion unit 10 performs a rotational coordinate conversion on the U-phase current iu, V-phase current iv, and W-phase current iw detected by the current sensors 7a to 7c, respectively, to determine the d-axis current detection value Idf and the q-axis current detection value Iqf, and outputs these current detection values to the rotation speed estimation unit 11. Note that the coordinate conversion unit 10 determines the d-axis current detection value Idf and the q-axis current detection value Iqf by defining the direction of the rotating magnetic field of the induction motor 3 as the d-axis direction and the direction of the current flowing to generate torque as the q-axis direction.
　回転速度推定部１１は、パタン生成部９と電流指令生成部８からそれぞれ入力される励磁電流指令Ｉｄｐ２およびｑ軸電流指令Ｉｑｐと、座標変換部１０から入力されるｄ軸電流検出値Ｉｄｆおよびｑ軸電流検出値Ｉｑｆとに基づき、誘導電動機３のロータ角周波数を推定し、その推定結果をロータ角周波数推定値ωｒｅとして出力する。 The rotational speed estimation unit 11 estimates the rotor angular frequency of the induction motor 3 based on the excitation current command Idp2 and the q-axis current command Iqp input from the pattern generation unit 9 and the current command generation unit 8, respectively, and the d-axis current detection value Idf and the q-axis current detection value Iqf input from the coordinate conversion unit 10, and outputs the estimation result as the rotor angular frequency estimate value ωre.
　周波数指令生成部１２には、パタン生成部９により求められたｄ軸磁束指令φｄｐと、電流指令生成部８により生成されたｑ軸電流指令Ｉｑｐと、回転速度推定部１１により推定されたロータ角周波数推定値ωｒｅとが入力される。周波数指令生成部１２は、これらの入力情報に基づいて、誘導電動機３に印加する交流電圧の角周波数を演算し、一次角周波数ω１として出力する。 The frequency command generating unit 12 receives the d-axis magnetic flux command φdp calculated by the pattern generating unit 9, the q-axis current command Iqp generated by the current command generating unit 8, and the rotor angular frequency estimate ωre estimated by the rotational speed estimating unit 11. Based on this input information, the frequency command generating unit 12 calculates the angular frequency of the AC voltage applied to the induction motor 3, and outputs it as the primary angular frequency ω1.
　電圧指令生成部１３には、直流電圧センサ６により検出された直流電圧Ｅｃｆと、パタン生成部９により求められた励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐと、電流指令生成部８により生成されたｑ軸電流指令Ｉｑｐと、回転速度推定部１１により求められたロータ角周波数推定値ωｒｅと、周波数指令生成部１２により求められた一次角周波数ω１とが入力される。電圧指令生成部１３は、これらの入力情報に基づいて電力変換回路１の変調率Ｖｃと電圧指令偏角δを演算し、その演算結果を電力変換回路１から誘導電動機３への出力電圧に対する電圧指令として出力する。 The voltage command generating unit 13 receives as input the DC voltage Ecf detected by the DC voltage sensor 6, the excitation current command Idp2 and the d-axis magnetic flux command φdp calculated by the pattern generating unit 9, the q-axis current command Iqp generated by the current command generating unit 8, the rotor angular frequency estimate ωre calculated by the rotational speed estimating unit 11, and the primary angular frequency ω1 calculated by the frequency command generating unit 12. The voltage command generating unit 13 calculates the modulation factor Vc and voltage command deflection angle δ of the power conversion circuit 1 based on this input information, and outputs the calculation result as a voltage command for the output voltage from the power conversion circuit 1 to the induction motor 3.
　パルス指令生成部１４は、電圧指令生成部１３により生成された電圧指令である変調率Ｖｃおよび電圧指令偏角δと、周波数指令生成部１２により求められた一次角周波数ω１とに基づき、電力変換回路１の半導体スイッチング素子５ａ～５ｆに対するゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２をそれぞれ演算する。パルス指令生成部１４により求められたゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２は、前述のように制御装置２から電力変換回路１へ出力され、電力変換回路１の各半導体スイッチング素子５ａ～５ｆの駆動制御に利用される。 The pulse command generating unit 14 calculates gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 for the semiconductor switching elements 5a to 5f of the power conversion circuit 1 based on the modulation factor Vc and voltage command argument δ, which are voltage commands generated by the voltage command generating unit 13, and the primary angular frequency ω1 determined by the frequency command generating unit 12. The gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 determined by the pulse command generating unit 14 are output from the control device 2 to the power conversion circuit 1 as described above, and are used to control the drive of each of the semiconductor switching elements 5a to 5f of the power conversion circuit 1.
　なお、図２の機能ブロック図では、回転速度推定部１１により誘導電動機３のロータ角周波数推定値ωｒｅを求めることで、速度センサレス制御を実現した電力変換装置の例を示している。以下ではこの例を用いて本発明の説明を行うが、回転速度推定部１１の代わりに速度センサを設け、この速度センサによって誘導電動機３の回転速度を検出する速度センサ付き制御においても、本発明の適用は可能である。すなわち、以下で説明する実施形態は、本発明の構成を限定するものではない。 The functional block diagram of FIG. 2 shows an example of a power conversion device that realizes speed sensorless control by using the rotation speed estimation unit 11 to determine the rotor angular frequency estimate ωre of the induction motor 3. The present invention will be explained below using this example, but the present invention can also be applied to speed sensor-equipped control in which a speed sensor is provided instead of the rotation speed estimation unit 11 and the rotation speed of the induction motor 3 is detected by this speed sensor. In other words, the configuration of the present invention is not limited to the embodiment described below.
　図３は、本発明の第１の実施形態に係るパタン生成部９の詳細を示す制御ブロック図である。本実施形態において、パタン生成部９は、例えば図３に示すように、切替接点１５、加算器１６、切替接点１７、遅延要素１８、減算器１９、ゲイン２０、積分要素２１、切替接点２２、ゲイン２３、切替接点２４、遅延要素２５、乗算器２６、除算器２７、ゲイン２８および微分要素２９を組み合わせて構成される。 FIG. 3 is a control block diagram showing details of the pattern generation unit 9 according to the first embodiment of the present invention. In this embodiment, the pattern generation unit 9 is configured by combining a switching contact 15, an adder 16, a switching contact 17, a delay element 18, a subtractor 19, a gain 20, an integral element 21, a switching contact 22, a gain 23, a switching contact 24, a delay element 25, a multiplier 26, a divider 27, a gain 28, and a differential element 29, for example, as shown in FIG. 3.
　なお、前述のようにパタン生成部９は、誘導電動機３の制御状態に応じて、励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐの演算方法を切り替える。具体的には、電力変換回路１から交流電力を出力して誘導電動機３を所定のトルクで駆動するように電力変換回路１の動作を制御する場合（以下「通常時制御」と称する）と、電力変換回路１から誘導電動機３への交流電力の出力を遮断するように電力変換回路１の動作を制御する場合（以下「遮断時制御」と称する）とで、パタン生成部９における励磁電流指令Ｉｄｐ２とｄ軸磁束指令φｄｐの演算方法を切り替える。この演算方法の切替は、例えば、制御装置２に入力される制御指令ｃｍｄに基づいて行うことができる。 As described above, the pattern generation unit 9 switches the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command φdp depending on the control state of the induction motor 3. Specifically, the calculation method of the excitation current command Idp2 and the d-axis magnetic flux command φdp in the pattern generation unit 9 is switched between a case where the operation of the power conversion circuit 1 is controlled so that AC power is output from the power conversion circuit 1 to drive the induction motor 3 with a predetermined torque (hereinafter referred to as "normal control") and a case where the operation of the power conversion circuit 1 is controlled so that the output of AC power from the power conversion circuit 1 to the induction motor 3 is cut off (hereinafter referred to as "cut-off control"). This switching of the calculation method can be performed, for example, based on the control command cmd input to the control device 2.
　切替接点１５は、パタン生成部９から出力される励磁電流指令Ｉｄｐ２の切替を行う。パタン生成部９は、通常時制御の実施中は、電流指令生成部８から入力されるｄ軸電流指令Ｉｄｐ１を励磁電流指令Ｉｄｐ２として出力し、遮断時制御の実施中は、加算器１６の出力を励磁電流指令Ｉｄｐ２として出力するように、切替接点１５を切り替える。 The switching contact 15 switches the excitation current command Idp2 output from the pattern generating unit 9. The pattern generating unit 9 switches the switching contact 15 so that during normal control, it outputs the d-axis current command Idp1 input from the current command generating unit 8 as the excitation current command Idp2, and during cut-off control, it outputs the output of the adder 16 as the excitation current command Idp2.
　加算器１６は、ｄ軸電流指令Ｉｄｐ１に微分要素２９の出力を加算する。この加算値は、前述のように遮断時制御における励磁電流指令Ｉｄｐ２として、加算器１６から切替接点１５を介して出力される。 Adder 16 adds the output of differential element 29 to d-axis current command Idp1. This added value is output from adder 16 via switching contact 15 as excitation current command Idp2 during cutoff control, as described above.
　切替接点１７は、ｄ軸電流指令保持値Ｉｄｐｈの切替を行う。パタン生成部９は、通常時制御の実施中は、電流指令生成部８から出力されてパタン生成部９に入力されるｄ軸電流指令Ｉｄｐ１をｄ軸電流指令保持値Ｉｄｐｈとし、遮断時制御の実施中は、遅延要素１８の出力をｄ軸電流指令保持値Ｉｄｐｈとするように、切替接点１７を切り替える。遅延要素１８は、切替接点１７の出力を遅延させて出力する。 The switching contact 17 switches the d-axis current command hold value Idph. During normal control, the pattern generating unit 9 switches the switching contact 17 so that the d-axis current command Idp1 output from the current command generating unit 8 and input to the pattern generating unit 9 is the d-axis current command hold value Idph, and during cut-off control, the pattern generating unit 9 switches the switching contact 17 so that the output of the delay element 18 is the d-axis current command hold value Idph. The delay element 18 delays the output of the switching contact 17 and outputs it.
　上述の切替接点１７と遅延要素１８の動作により、通常時制御の実施中は、電流指令生成部８からパタン生成部９に入力されるｄ軸電流指令Ｉｄｐ１の値に応じてｄ軸電流指令保持値Ｉｄｐｈが逐次更新される。一方、通常時制御から遮断時制御への切替後は、切替直前に電流指令生成部８からパタン生成部９に入力されたｄ軸電流指令Ｉｄｐ１の値が、ｄ軸電流指令保持値Ｉｄｐｈとして保持される。 Due to the operation of the switching contact 17 and delay element 18 described above, during normal control, the d-axis current command hold value Idph is successively updated according to the value of the d-axis current command Idp1 input from the current command generation unit 8 to the pattern generation unit 9. On the other hand, after switching from normal control to interruption control, the value of the d-axis current command Idp1 input from the current command generation unit 8 to the pattern generation unit 9 immediately before switching is held as the d-axis current command hold value Idph.
　減算器１９は、ｄ軸電流指令Ｉｄｐ１から積分要素２１の出力を減算する。この減算値は、ゲイン２０へ出力される。 Subtractor 19 subtracts the output of integral element 21 from d-axis current command Idp1. This subtracted value is output to gain 20.
　ゲイン２０は、減算器１９の出力に、予め設定された誘導電動機３の二次時定数Ｔ２の逆数を乗算する。この乗算値は、積分要素２１へ出力される。 Gain 20 multiplies the output of subtractor 19 by the inverse of the preset secondary time constant T2 of induction motor 3. This multiplied value is output to integral element 21.
　積分要素２１は、ゲイン２０の出力を積算する。この積算値は、積分要素２１、切替接点２２、切替接点２４へ出力される。 Integral element 21 accumulates the output of gain 20. This accumulated value is output to integral element 21, switching contact 22, and switching contact 24.
　切替接点２２は、ゲイン２３に入力される磁化電流指令Ｉ０の切替を行う。パタン生成部９は、通常時制御の実施中は、積分要素２１の出力が磁化電流指令Ｉ０としてゲイン２３に入力され、遮断時制御の実施中は、除算器２７の出力が磁化電流指令Ｉ０としてゲイン２３に入力されるように、切替接点２２を切り替える。 The switching contact 22 switches the magnetization current command I0 input to the gain 23. The pattern generating unit 9 switches the switching contact 22 so that during normal control, the output of the integral element 21 is input to the gain 23 as the magnetization current command I0, and during cut-off control, the pattern generating unit 9 switches the switching contact 22 so that the output of the divider 27 is input to the gain 23 as the magnetization current command I0.
　ゲイン２３は、切替接点２２から入力される磁化電流指令Ｉ０に、予め設定された誘導電動機３の励磁インダクタンスＬを乗算する。この乗算値は、パタン生成部９からｄ軸磁束指令φｄｐとして出力される。 Gain 23 multiplies the magnetization current command I0 input from switching contact 22 by the preset excitation inductance L of induction motor 3. This multiplied value is output from pattern generator 9 as d-axis magnetic flux command φdp.
　切替接点２４は、磁化電流指令保持値Ｉ０ｈの切替を行う。パタン生成部９は、通常時制御の実施中は、積分要素２１の出力を磁化電流指令保持値Ｉ０ｈとし、遮断時制御の実施中は、遅延要素２５の出力を磁化電流指令保持値Ｉ０ｈとするように、切替接点２４を切り替える。遅延要素２５は、切替接点２４の出力を遅延させて出力する。 The switching contact 24 switches the magnetization current command holding value I0h. The pattern generating unit 9 switches the switching contact 24 so that the output of the integral element 21 is the magnetization current command holding value I0h during normal control, and the output of the delay element 25 is the magnetization current command holding value I0h during cut-off control. The delay element 25 delays the output of the switching contact 24 and outputs it.
　上述の切替接点２４と遅延要素２５の動作により、通常時制御の実施中は、積分要素２１から出力されてゲイン２３に入力される磁化電流指令Ｉ０の値に応じて磁化電流指令保持値Ｉ０ｈが逐次更新される。一方、通常時制御から遮断時制御への切替後は、切替直前にゲイン２３に入力された磁化電流指令Ｉ０の値が、磁化電流指令保持値Ｉ０ｈとして保持される。 Due to the operation of the switching contact 24 and delay element 25 described above, during normal control, the magnetization current command holding value I0h is successively updated according to the value of the magnetization current command I0 output from the integral element 21 and input to the gain 23. On the other hand, after switching from normal control to interruption control, the value of the magnetization current command I0 input to the gain 23 immediately before switching is held as the magnetization current command holding value I0h.
　乗算器２６は、ｄ軸電流指令Ｉｄｐ１に磁化電流指令保持値Ｉ０ｈを乗算する。この乗算値は、除算器２７へ出力される。 The multiplier 26 multiplies the d-axis current command Idp1 by the magnetization current command hold value I0h. This multiplied value is output to the divider 27.
　除算器２７は、乗算器２６の出力をｄ軸電流指令保持値Ｉｄｐｈで除算する。この除算値は、切替接点２２とゲイン２８へ出力される。 The divider 27 divides the output of the multiplier 26 by the d-axis current command hold value Idph. This divided value is output to the switching contact 22 and the gain 28.
　ゲイン２８は、除算器２７の出力に、予め設定された誘導電動機３の二次時定数Ｔ２を乗算する。この乗算値は、微分要素２９へ出力される。 Gain 28 multiplies the output of divider 27 by a preset secondary time constant T2 of induction motor 3. This multiplied value is output to differential element 29.
　微分要素２９は、ゲイン２８の出力の時間変化量を算出する。この算出値は、加算器１６へ出力される。 The differential element 29 calculates the amount of change over time in the output of the gain 28. This calculated value is output to the adder 16.
　本実施形態のパタン生成部９では、上記のような各構成要素の動作により、ｄ軸電流指令Ｉｄｐ１に基づく励磁電流指令Ｉｄｐ２および磁化電流指令Ｉ０を求め、磁化電流指令Ｉ０と、誘導電動機３の特性に応じて予め設定された励磁インダクタンスＬとに基づいて、ｄ軸磁束指令φｄｐを生成することができる。具体的には、通常時制御の実施中は、ｄ軸電流指令Ｉｄｐ１から励磁電流指令Ｉｄｐ２を求めるとともに、ｄ軸電流指令Ｉｄｐ１と誘導電動機３の特性に応じて予め設定された二次時定数Ｔ２とに基づいて磁化電流指令Ｉ０を求めることができる。また、遮断時制御の実施中は、ｄ軸電流指令Ｉｄｐ１、磁化電流指令保持値Ｉ０ｈおよびｄ軸電流指令保持値Ｉｄｐｈに基づいて磁化電流指令Ｉ０を求めるとともに、磁化電流指令Ｉ０および二次時定数Ｔ２に基づいて励磁電流指令Ｉｄｐ２を求めることができる。 In the pattern generating unit 9 of this embodiment, the excitation current command Idp2 and magnetization current command I0 are obtained based on the d-axis current command Idp1 through the operation of each component as described above, and the d-axis magnetic flux command φdp can be generated based on the magnetization current command I0 and the excitation inductance L preset according to the characteristics of the induction motor 3. Specifically, during normal control, the excitation current command Idp2 can be obtained from the d-axis current command Idp1, and the magnetization current command I0 can be obtained based on the d-axis current command Idp1 and the secondary time constant T2 preset according to the characteristics of the induction motor 3. During interruption control, the magnetization current command I0 can be obtained based on the d-axis current command Idp1, the magnetization current command hold value I0h, and the d-axis current command hold value Idph, and the excitation current command Idp2 can be obtained based on the magnetization current command I0 and the secondary time constant T2.
　続いて、本実施形態の電力変換装置の動作について、代表的な動作例である図４～図６を参照して以下に説明する。 Next, the operation of the power conversion device of this embodiment will be described below with reference to Figures 4 to 6, which show representative operation examples.
　図４は、ｄ軸磁束指令φｄｐの立ち上げ完了後に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。なお図４では、本発明の適用例として図２、図３で説明した制御装置２を用いた場合の電力変換装置の動作例を示しているが、本発明を適用しない従来の制御方法でも同様の結果が得られる。 FIG. 4 shows an example of each command and state quantity when cutoff control is performed after the d-axis magnetic flux command φdp has been fully started. Note that FIG. 4 shows an example of the operation of a power conversion device when the control device 2 described in FIG. 2 and FIG. 3 is used as an application example of the present invention, but similar results can be obtained with a conventional control method to which the present invention is not applied.
　通常時指令がオン状態である場合、すなわち通常時制御の実施中には、前述のようにパタン生成部９において、切替接点１５，１７，２２，２４がそれぞれ通常時の切替状態となっている。図４の例では、ｄ軸電流指令Ｉｄｐ１の立ち上げ始めから一定値に至り遮断直前まで、この状態が継続している。一方、遮断時指令がオン状態である場合、すなわち遮断時制御の実施中には、前述のようにパタン生成部９において、切替接点１５，１７，２２，２４がそれぞれ遮断時の切替状態となる。図４の例では、ｄ軸電流指令Ｉｄｐ１の立ち下げからゼロに至るまで、この状態が継続している。 When the normal command is in the on state, i.e., while normal control is being performed, in the pattern generation unit 9, as described above, the switching contacts 15, 17, 22, and 24 are each in the normal switching state. In the example of Figure 4, this state continues from the start of the rise of the d-axis current command Idp1 until it reaches a constant value and immediately before it is cut off. On the other hand, when the cut-off command is in the on state, i.e., while cut-off control is being performed, in the pattern generation unit 9, as described above, the switching contacts 15, 17, 22, and 24 are each in the cut-off switching state. In the example of Figure 4, this state continues from the fall of the d-axis current command Idp1 until it reaches zero.
　また、図４の例では、ｄ軸電流指令Ｉｄｐ１を実線で示し、これに重ねて磁化電流指令Ｉ０を破線で示している。磁化電流指令Ｉ０は、通常時制御では減算器１９、ゲイン２０、積分要素２１および切替接点２２の動作により、ｄ軸電流指令Ｉｄｐ１に対して二次時定数Ｔ２の一次遅れとして動作する。 In the example of FIG. 4, the d-axis current command Idp1 is shown by a solid line, and the magnetization current command I0 is shown by a dashed line superimposed on it. During normal control, the magnetization current command I0 acts as a first-order lag with a second-order time constant T2 relative to the d-axis current command Idp1 due to the operation of the subtractor 19, gain 20, integral element 21, and switching contact 22.
　ｄ軸電流指令Ｉｄｐ１の立ち上げが終了して一定値に至った後、十分な時間が経過すると、図４に示すように、ｄ軸電流指令Ｉｄｐ１と磁化電流指令Ｉ０が一致する。そのため図４の例では、遮断時制御の実施中には、乗算器２６、除算器２７および切替接点２２の動作により、ｄ軸電流指令Ｉｄｐ１と磁化電流指令Ｉ０が同じ値となる。 After the d-axis current command Idp1 finishes rising and reaches a constant value, when sufficient time has passed, the d-axis current command Idp1 and the magnetization current command I0 will match, as shown in Figure 4. Therefore, in the example of Figure 4, during the interruption control, the d-axis current command Idp1 and the magnetization current command I0 will be the same value due to the operation of the multiplier 26, the divider 27, and the switching contact 22.
　一方、励磁電流指令Ｉｄｐ２は、切替接点１５、加算器１６、ゲイン２８および微分要素２９の動作により、通常時制御ではｄ軸電流指令Ｉｄｐ１と同じ値となり、遮断時制御では、ｄ軸電流指令Ｉｄｐ１に対して磁化電流指令Ｉ０の時間変化率（ｄＩ０／ｄｔ）に二次時定数Ｔ２を乗算して加算した値となる。 On the other hand, due to the operation of the switching contact 15, adder 16, gain 28 and differential element 29, the excitation current command Idp2 becomes the same value as the d-axis current command Idp1 during normal control, and during cut-off control, becomes the value obtained by multiplying the time rate of change of the magnetization current command I0 (dI0/dt) by the secondary time constant T2 and adding it to the d-axis current command Idp1.
　ｄ軸磁束指令φｄｐは、磁化電流指令Ｉ０に対して励磁インダクタンスＬを乗算したものである。図４では、励磁電流指令Ｉｄｐ２の定常値をＩｄｐ０と定義している。 The d-axis magnetic flux command φdp is the magnetization current command I0 multiplied by the excitation inductance L. In Figure 4, the steady-state value of the excitation current command Idp2 is defined as Idp0.
　通常時制御にｄ軸電流指令Ｉｄｐ１の立ち上げが完了して一定値に至ると、ｄ軸電流指令Ｉｄｐ１の値は、励磁電流指令Ｉｄｐ２および磁化電流指令Ｉ０と一致する。このときのｄ軸磁束指令φｄｐの値は、励磁電流指令Ｉｄｐ２の定常値Ｉｄｐ０に励磁インダクタンスＬを乗算した値と等しくなる。この状態で通常時制御から遮断時制御への切替を行うと、ｄ軸磁束指令φｄｐの値は、上記の乗算値から連続して変化する。その結果、ｄ軸電流指令Ｉｄｐ１の立ち下げ開始からゼロに至るまでの期間において、ｄ軸磁束指令φｄｐによる指令値をアンダーシュートすることなく、ｄ軸磁束φｄをゼロまで低下させることができる。これにより、電力変換回路１を遮断する際に、ｄ軸磁束φｄを残留させずに減衰することができる。 When the rise of the d-axis current command Idp1 in normal control is completed and reaches a constant value, the value of the d-axis current command Idp1 coincides with the excitation current command Idp2 and the magnetization current command I0. The value of the d-axis magnetic flux command φdp at this time is equal to the value obtained by multiplying the steady-state value Idp0 of the excitation current command Idp2 by the excitation inductance L. When switching from normal control to cut-off control in this state, the value of the d-axis magnetic flux command φdp changes continuously from the above multiplied value. As a result, during the period from when the d-axis current command Idp1 starts to fall until it reaches zero, the d-axis magnetic flux φd can be reduced to zero without undershooting the command value by the d-axis magnetic flux command φdp. This allows the d-axis magnetic flux φd to be attenuated without remaining when the power conversion circuit 1 is cut off.
　次に、本発明を適用しない場合の遮断時制御における問題点について、以下に図５の動作例を用いて説明する。図５は、従来の制御方法によりｄ軸磁束指令φｄｐの立ち上げ完了前に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。図５では図４とは異なり、ｄ軸磁束指令φｄｐを立ち上げ始めてから一定値となる前に、ｄ軸電流指令Ｉｄｐ１を立ち下げる動作波形の例を示している。なお図５において、図４と同様の動きをする各指令と状態量については、以下で説明を省略する。 Next, problems with cutoff control when the present invention is not applied will be explained below using the operation example of Figure 5. Figure 5 is a diagram showing an example of each command and state quantity when cutoff control is performed before the rise of the d-axis magnetic flux command φdp is completed using a conventional control method. Unlike Figure 4, Figure 5 shows an example of an operation waveform in which the d-axis current command Idp1 falls after the d-axis magnetic flux command φdp starts to rise and before it reaches a constant value. Note that explanations of each command and state quantity in Figure 5 that behave in the same way as in Figure 4 will be omitted below.
　従来の制御方法では、図４のようにｄ軸磁束指令φｄｐの立ち上がりが完了して一定値となった状態で、通常時制御から遮断時制御に遷移する場合には、ｄ軸磁束φｄを十分に減衰可能である。しかしながら、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に遷移すると、図５のようにｄ軸磁束指令φｄｐが不連続となり、ｄ軸磁束指令φｄｐとして過剰に大きな指令値が出力されることになる。その結果、ｄ軸磁束φｄがゼロを跨いでアンダーシュートすることで、電力変換装置が停止した後にも、誘導電動機３の内部にｄ軸磁束φｄが残留する。このように誘導電動機３の内部にｄ軸磁束φｄが残留した状態で電力変換装置を再起動させると、過大な電流やトルクが発生する要因となる。これを防ぐためには、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に遷移しても、ｄ軸磁束指令φｄｐが不連続にならず、ｄ軸磁束φｄをゼロに至るまで一定の変化率で減衰することが必要である。 In the conventional control method, when the d-axis magnetic flux command φdp has completed rising and is at a constant value as shown in FIG. 4, the d-axis magnetic flux φd can be sufficiently attenuated when transitioning from normal control to cutoff control. However, when transitioning from normal control to cutoff control occurs during the rise of the d-axis magnetic flux command φdp, the d-axis magnetic flux command φdp becomes discontinuous as shown in FIG. 5, and an excessively large command value is output as the d-axis magnetic flux command φdp. As a result, the d-axis magnetic flux φd crosses zero and undershoots, so that the d-axis magnetic flux φd remains inside the induction motor 3 even after the power conversion device is stopped. If the power conversion device is restarted in this state where the d-axis magnetic flux φd remains inside the induction motor 3, excessive current and torque will be generated. To prevent this, even if transitioning from normal control to cutoff control occurs during the rise of the d-axis magnetic flux command φdp, it is necessary that the d-axis magnetic flux command φdp does not become discontinuous and that the d-axis magnetic flux φd is attenuated at a constant rate of change until it reaches zero.
　本実施形態の電力変換装置では、上述の課題を解決し、電力変換装置を遮断する際には誘導電動機３の磁束を十分に減衰させる手段を設けている。具体的には、図３で説明したように、制御装置２のパタン生成部９において、切替接点１７と遅延要素１８により、通常時制御から遮断時制御に切り替える直前のｄ軸電流指令Ｉｄｐ１をｄ軸電流指令保持値Ｉｄｐｈとして保持するとともに、切替接点２４と遅延要素２５により、通常時制御から遮断時制御に切り替える直前の磁化電流指令Ｉ０を、磁化電流指令保持値Ｉ０ｈとして保持するようにしている。そして、乗算器２６と除算器２７により、ｄ軸電流指令Ｉｄｐ１に磁化電流指令保持値Ｉ０ｈを乗算した値をｄ軸電流指令保持値Ｉｄｐｈで割ることで、遮断時制御の実施中における磁化電流指令Ｉ０を算出するようにしている。 The power conversion device of this embodiment solves the above-mentioned problems and provides a means for sufficiently attenuating the magnetic flux of the induction motor 3 when the power conversion device is shut down. Specifically, as described in FIG. 3, in the pattern generation unit 9 of the control device 2, the switching contact 17 and delay element 18 are used to hold the d-axis current command Idp1 immediately before switching from normal control to shut-down control as the d-axis current command hold value Idph, and the switching contact 24 and delay element 25 are used to hold the magnetization current command I0 immediately before switching from normal control to shut-down control as the magnetization current command hold value I0h. The multiplier 26 and divider 27 then multiply the d-axis current command Idp1 by the magnetization current command hold value I0h and divide the result by the d-axis current command hold value Idph to calculate the magnetization current command I0 during the shut-down control.
　これにより、ｄ軸磁束指令φｄｐの立ち上げ途中に遮断時制御に遷移しても、その直前における磁化電流指令保持値Ｉ０ｈに対するｄ軸電流指令保持値Ｉｄｐｈの比率で、ｄ軸電流指令Ｉｄｐ１を補正することができる。その結果、磁化電流指令Ｉ０を連続した値とすることができ、この磁化電流指令Ｉ０を用いて、連続的に減少するｄ軸磁束指令φｄｐを算出することができる。すなわち、ｄ軸磁束φｄをゼロに至るまで一定の変化率で減衰させ、誘導電動機３の内部にｄ軸磁束φｄが残留するのを防止できる。 As a result, even if control transitions to cut-off control while the d-axis flux command φdp is rising, the d-axis current command Idp1 can be corrected by the ratio of the d-axis current command holding value Idph to the magnetization current command holding value I0h immediately before that. As a result, the magnetization current command I0 can be made a continuous value, and the magnetization current command I0 can be used to calculate the d-axis flux command φdp, which decreases continuously. In other words, the d-axis flux φd is attenuated at a constant rate of change until it reaches zero, preventing the d-axis flux φd from remaining inside the induction motor 3.
　また、本実施形態の電力変換装置では、ｄ軸電流指令Ｉｄｐ１を補正した値を基にｄ軸磁束指令φｄｐを算出する。そのため、ｄ軸電流指令Ｉｄｐ１の立ち下げ時間（ｄ軸電流指令立下時間Ｔｄ）の間に、ｄ軸磁束指令φｄｐを遮断直前からゼロに至るまで一定の変化率で立ち下げることができる。 In addition, in the power conversion device of this embodiment, the d-axis magnetic flux command φdp is calculated based on the corrected value of the d-axis current command Idp1. Therefore, during the fall time of the d-axis current command Idp1 (d-axis current command fall time Td), the d-axis magnetic flux command φdp can be fallen at a constant rate of change from just before interruption to zero.
　図６は、本発明の第１の実施形態に係る電力変換装置において、ｄ軸磁束指令φｄｐの立ち上げ完了前に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。なお図６において、図４と同様の動きをする各指令と状態量については、以下で説明を省略する。 FIG. 6 is a diagram showing an example of each command and state quantity when cutoff control is performed before the start-up of the d-axis magnetic flux command φdp is completed in the power conversion device according to the first embodiment of the present invention. Note that in FIG. 6, the commands and state quantities that behave in the same way as in FIG. 4 will not be described below.
　図６では図５と同様に、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に遷移しているが、本実施形態の電力変換装置では前述のように、磁化電流指令保持値Ｉ０ｈに対するｄ軸電流指令保持値Ｉｄｐｈの比率でｄ軸電流指令Ｉｄｐ１を補正し、これを磁化電流指令Ｉ０としてｄ軸磁束指令φｄｐを求める。この効果により、図６に示すように、通常時制御から遮断時制御への切替前後でｄ軸磁束指令φｄｐを連続して変化させ、ｄ軸磁束φｄをゼロに至るまで一定の変化率で減衰させることができる。このときのｄ軸磁束指令φｄｐの立ち下げ時間は、ｄ軸電流指令立下時間Ｔｄと一致する。 In Figure 6, as in Figure 5, there is a transition from normal control to interruption control during the rise of the d-axis flux command φdp, but in the power conversion device of this embodiment, as described above, the d-axis current command Idp1 is corrected by the ratio of the d-axis current command hold value Idph to the magnetization current command hold value I0h, and the d-axis flux command φdp is calculated using this as the magnetization current command I0. Due to this effect, as shown in Figure 6, the d-axis flux command φdp can be changed continuously before and after switching from normal control to interruption control, and the d-axis flux φd can be attenuated at a constant rate of change until it reaches zero. The fall time of the d-axis flux command φdp at this time coincides with the d-axis current command fall time Td.
　なお、遮断時制御の実施中における励磁電流指令Ｉｄｐ２の値は、磁化電流指令Ｉ０の時間変化率（ｄＩ０／ｄｔ）に誘導電動機３の二次時定数Ｔ２を乗算し、これをｄ軸電流指令Ｉｄｐ１に加算することで算出される。磁化電流指令Ｉ０は一定の変化率で減少するため、このときの励磁電流指令Ｉｄｐ２の値は、ｄ軸電流指令Ｉｄｐ１を負方向に平行移動させた値となる。 The value of the excitation current command Idp2 during interruption control is calculated by multiplying the time rate of change of the magnetization current command I0 (dI0/dt) by the secondary time constant T2 of the induction motor 3 and adding this to the d-axis current command Idp1. Since the magnetization current command I0 decreases at a constant rate of change, the value of the excitation current command Idp2 at this time is the value obtained by translating the d-axis current command Idp1 in the negative direction.
　以上説明したように、本実施形態の電力変換装置では、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に状態遷移した場合でも、誘導電動機３における実際のｄ軸磁束φｄを一定の変化率で立ち下げることができる。その結果、ｄ軸磁束φｄをアンダーシュートすることなくゼロまで減衰させることができる。すなわち、電力変換装置を遮断するときのｄ軸磁束φｄの残留量をゼロにできる。そのため、電力変換装置を再起動させる際の過大な電流やトルクの発生を抑制することができる。 As described above, in the power conversion device of this embodiment, even when the state transition occurs from normal control to cut-off control during the rise of the d-axis magnetic flux command φdp, the actual d-axis magnetic flux φd in the induction motor 3 can be lowered at a constant rate of change. As a result, the d-axis magnetic flux φd can be attenuated to zero without undershooting. In other words, the residual amount of the d-axis magnetic flux φd when the power conversion device is cut off can be made zero. Therefore, the generation of excessive current and torque when the power conversion device is restarted can be suppressed.
　以上説明した本発明の第１の実施形態によれば、以下の作用効果を奏する。 The first embodiment of the present invention described above provides the following effects.
（１）電力変換装置は、直流電力を交流電力に変換して誘導電動機３を駆動する電力変換回路１と、電力変換回路１にゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２を出力して電力変換回路１を制御する制御装置２とを備える。制御装置２は、ゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２の生成に用いられるｄ軸電流指令Ｉｄｐ１、励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐを求めるとともに、ｄ軸電流指令Ｉｄｐ１の立ち下げ開始直前におけるｄ軸磁束指令φｄｐの値に応じた磁化電流指令保持値Ｉ０ｈおよびｄ軸電流指令保持値Ｉｄｐｈを保持可能であり、電力変換回路１を遮断する際には、これらの保持値に基づいてｄ軸電流指令Ｉｄｐ１、励磁電流指令Ｉｄｐ２およびｄ軸磁束指令φｄｐを求める。このようにしたので、ｄ軸磁束指令φｄｐを立ち上げる途中で電力変換装置を遮断する場合でも、誘導電動機３内部の残留磁束を十分に減衰できる。 (1) The power conversion device includes a power conversion circuit 1 that converts DC power into AC power to drive an induction motor 3, and a control device 2 that outputs gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 to the power conversion circuit 1 to control the power conversion circuit 1. The control device 2 determines the d-axis current command Idp1, the excitation current command Idp2, and the d-axis flux command φdp used to generate the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2, and is capable of holding a magnetization current command holding value I0h and a d-axis current command holding value Idph according to the value of the d-axis flux command φdp immediately before the d-axis current command Idp1 starts to fall, and determines the d-axis current command Idp1, the excitation current command Idp2, and the d-axis flux command φdp based on these held values when the power conversion circuit 1 is shut off. This allows the residual magnetic flux inside the induction motor 3 to be sufficiently attenuated even if the power conversion device is shut off while the d-axis magnetic flux command φdp is rising.
（２）制御装置２には、電力変換回路１を運転または停止させる制御指令ｃｍｄが入力される。制御装置２は、制御指令ｃｍｄに基づいて、ｄ軸電流指令Ｉｄｐ１の立ち下げ開始前の期間に対する通常時制御、または、ｄ軸電流指令Ｉｄｐ１の立ち下げ開始後の期間に対する遮断時制御のいずれかを実施し、通常時制御から遮断時制御への切替直前のｄ軸磁束指令φｄｐの値に応じた保持値を保持可能である。具体的には、制御装置２は、制御指令ｃｍｄに応じたｄ軸電流指令Ｉｄｐ１およびｑ軸電流指令Ｉｑｐを生成する電流指令生成部８と、ｄ軸電流指令Ｉｄｐ１に基づく励磁電流指令Ｉｄｐ２および磁化電流指令Ｉ０を求め、磁化電流指令Ｉ０と、誘導電動機３の特性に応じて予め設定された励磁インダクタンスＬとに基づいて、ｄ軸磁束指令φｄｐを生成するパタン生成部９と、励磁電流指令Ｉｄｐ２、ｄ軸磁束指令φｄｐおよびｑ軸電流指令Ｉｑｐに基づいて電圧指令を生成する電圧指令生成部１３と、この電圧指令に基づいてゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２を生成するパルス指令生成部１４と、を有する。パタン生成部９は、通常時制御から遮断時制御への切替直前における磁化電流指令Ｉ０の値を、磁化電流指令保持値Ｉ０ｈとして保持する。このようにしたので、ｄ軸磁束指令φｄｐを立ち上げる途中で電力変換装置を遮断する場合に、誘導電動機３内部の残留磁束を十分に減衰可能なゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２を生成することができる。 (2) A control command cmd for operating or stopping the power conversion circuit 1 is input to the control device 2. Based on the control command cmd, the control device 2 performs either normal control for the period before the d-axis current command Idp1 starts to fall, or interruption control for the period after the d-axis current command Idp1 starts to fall, and is capable of holding a holding value corresponding to the value of the d-axis magnetic flux command φdp immediately before switching from normal control to interruption control. Specifically, the control device 2 has a current command generating unit 8 that generates a d-axis current command Idp1 and a q-axis current command Iqp according to the control command cmd, a pattern generating unit 9 that determines an excitation current command Idp2 and a magnetization current command I0 based on the d-axis current command Idp1 and generates a d-axis magnetic flux command φdp based on the magnetization current command I0 and an excitation inductance L that is preset according to the characteristics of the induction motor 3, a voltage command generating unit 13 that generates a voltage command based on the excitation current command Idp2, the d-axis magnetic flux command φdp, and the q-axis current command Iqp, and a pulse command generating unit 14 that generates gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, Sw2 based on the voltage command. The pattern generating unit 9 holds the value of the magnetization current command I0 immediately before switching from the normal control to the cutoff control as a magnetization current command holding value I0h. By doing this, when the power conversion device is shut off during the rise of the d-axis magnetic flux command φdp, gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 can be generated that can sufficiently attenuate the residual magnetic flux inside the induction motor 3.
（３）パタン生成部９は、通常時制御の実施中は、切替接点１５により、ｄ軸電流指令Ｉｄｐ１から励磁電流指令Ｉｄｐ２を求めるとともに、減算器１９、ゲイン２０、積分要素２１および切替接点２２により、ｄ軸電流指令Ｉｄｐ１と誘導電動機３の特性に応じて予め設定された二次時定数Ｔ２とに基づいて磁化電流指令Ｉ０を求める。また、遮断時制御の実施中は、切替接点２４、遅延要素２５、乗算器２６および除算器２７により、ｄ軸電流指令Ｉｄｐ１、磁化電流指令保持値Ｉ０ｈおよびｄ軸電流指令保持値Ｉｄｐｈに基づいて磁化電流指令Ｉ０を求めるとともに、ゲイン２８、微分要素２９および加算器１６により、磁化電流指令Ｉ０および二次時定数Ｔ２に基づいて励磁電流指令Ｉｄｐ２を求める。このようにしたので、通常時制御および遮断時制御のそれぞれにおいて、ゲートパルス信号Ｓｕ１，Ｓｕ２，Ｓｖ１，Ｓｖ２，Ｓｗ１，Ｓｗ２の生成に必要な励磁電流指令Ｉｄｐ２および磁化電流指令Ｉ０の値を適切に求めることができる。 (3) During normal control, the pattern generator 9 uses the switch contact 15 to determine the excitation current command Idp2 from the d-axis current command Idp1, and uses the subtractor 19, gain 20, integral element 21, and switch contact 22 to determine the magnetization current command I0 based on the d-axis current command Idp1 and a secondary time constant T2 preset according to the characteristics of the induction motor 3. During cutoff control, the pattern generator 9 uses the switch contact 24, delay element 25, multiplier 26, and divider 27 to determine the magnetization current command I0 based on the d-axis current command Idp1, the magnetization current command hold value I0h, and the d-axis current command hold value Idph, and uses the gain 28, differential element 29, and adder 16 to determine the excitation current command Idp2 based on the magnetization current command I0 and the secondary time constant T2. In this way, the values of the excitation current command Idp2 and magnetization current command I0 required to generate the gate pulse signals Su1, Su2, Sv1, Sv2, Sw1, and Sw2 can be appropriately determined in both normal control and interruption control.
（４）パタン生成部９は、通常時制御から遮断時制御への切替後に、磁化電流指令保持値Ｉ０ｈおよびｄ軸電流指令保持値Ｉｄｐｈを保持し続ける。具体的には、パタン生成部９は、切替接点２４および遅延要素２５と、切替接点１７および遅延要素１８とにより、通常時制御から遮断時制御への切替直前における磁化電流指令Ｉ０の値および励磁電流指令Ｉｄｐ２の値を、磁化電流指令保持値Ｉ０ｈおよびｄ軸電流指令保持値Ｉｄｐｈとしてそれぞれ保持する。また、乗算器２６および除算器２７により、ｄ軸電流指令Ｉｄｐ１と磁化電流指令保持値Ｉ０ｈとの積をｄ軸電流指令保持値Ｉｄｐｈで割った値を、遮断時制御の実施中における磁化電流指令Ｉ０の値として求める。このようにしたので、ｄ軸磁束指令φｄｐの立ち上げ途中に遮断時制御に遷移しても、連続的に変化する磁化電流指令Ｉ０の値を算出することができる。その結果、ｄ軸磁束φｄをゼロに至るまで一定の変化率で減衰させ、誘導電動機３の内部にｄ軸磁束φｄが残留するのを確実に防止できる。 (4) After switching from normal control to interruption control, the pattern generation unit 9 continues to hold the magnetization current command hold value I0h and the d-axis current command hold value Idph. Specifically, the pattern generation unit 9 holds the value of the magnetization current command I0 and the value of the excitation current command Idp2 immediately before switching from normal control to interruption control as the magnetization current command hold value I0h and the d-axis current command hold value Idph, respectively, using the switching contact 24 and delay element 25, and the switching contact 17 and delay element 18. In addition, the multiplier 26 and divider 27 divide the product of the d-axis current command Idp1 and the magnetization current command hold value I0h by the d-axis current command hold value Idph to obtain the value of the magnetization current command I0 during the interruption control. In this way, even if the control transitions to the interruption control during the rise of the d-axis magnetic flux command φdp, the value of the magnetization current command I0, which changes continuously, can be calculated. As a result, the d-axis magnetic flux φd is attenuated at a constant rate until it reaches zero, and the d-axis magnetic flux φd is reliably prevented from remaining inside the induction motor 3.
（第２の実施形態）
　次に、本発明の第２の実施形態について説明する。本実施形態では、第１の実施形態に対して、磁化電流指令Ｉ０の演算方法が異なる例を説明する。以下では、第１の実施形態との相違点を中心に説明する。 Second Embodiment
Next, a second embodiment of the present invention will be described. In this embodiment, an example in which the method of calculating the magnetization current command I0 is different from that in the first embodiment will be described. The following mainly describes the differences from the first embodiment.
　本実施形態の電力変換装置は、第１の実施形態で説明した図１の電力変換装置と同様の構成を有しているが、制御装置２の機能構成が異なる。 The power conversion device of this embodiment has a similar configuration to the power conversion device of FIG. 1 described in the first embodiment, but the functional configuration of the control device 2 is different.
　図７は、本発明の第２の実施形態に係る制御装置２の詳細を示す機能ブロック図である。本実施形態では、図２で説明した第１の実施形態と比べて、パタン生成部９がパタン生成部９Ａに置き換えられており、電流指令生成部８からパタン生成部９Ａに対して、ｄ軸電流指令Ｉｄｐ１に加えて、さらにｄ軸電流指令立下時間Ｔｄを出力する点が異なっている。これは、パタン生成部９Ａにおいて、遮断時の磁化電流指令Ｉ０およびｄ軸磁束指令φｄｐの演算に、ｄ軸電流指令立下時間Ｔｄを用いるためである。 FIG. 7 is a functional block diagram showing details of a control device 2 according to a second embodiment of the present invention. In this embodiment, compared to the first embodiment described in FIG. 2, the pattern generator 9 is replaced with a pattern generator 9A, and in addition to the d-axis current command Idp1, the current command generator 8 outputs the d-axis current command fall time Td to the pattern generator 9A. This is because the pattern generator 9A uses the d-axis current command fall time Td to calculate the magnetization current command I0 and the d-axis magnetic flux command φdp at the time of interruption.
　図８は、本発明の第２の実施形態に係るパタン生成部９Ａの詳細を示す制御ブロック図である。本実施形態のパタン生成部９Ａは、ｄ軸電流指令立下時間Ｔｄの入力を追加し、第１の実施形態で説明した図３のパタン生成部９における切替接点１７、遅延要素１８、切替接点２２、乗算器２６、除算器２７および微分要素２９の代わりに、除算器３０、ゲイン３１および切替接点３２を備えて構成される。 FIG. 8 is a control block diagram showing details of a pattern generator 9A according to a second embodiment of the present invention. The pattern generator 9A of this embodiment adds an input of the d-axis current command fall time Td, and is configured with a divider 30, gain 31, and switch contact 32 instead of the switch contact 17, delay element 18, switch contact 22, multiplier 26, divider 27, and differential element 29 in the pattern generator 9 of FIG. 3 described in the first embodiment.
　除算器３０は、磁化電流指令保持値Ｉ０ｈをｄ軸電流指令立下時間Ｔｄで除算する。この除算値は、ゲイン３１へ出力される。 The divider 30 divides the magnetization current command holding value I0h by the d-axis current command falling time Td. This divided value is output to the gain 31.
　ゲイン３１は、除算器３０の出力に－１を乗算することで正負を反転させ、ゲイン２８と切替接点３２へ出力する。 Gain 31 inverts the output of divider 30 by multiplying it by -1, and outputs it to gain 28 and switching contact 32.
　なお、本実施形態のパタン生成部９Ａでは、ゲイン２８の出力側に微分要素２９が設けられていない。そのため、ゲイン２８は、ゲイン３１により正負が反転された除算器３０の出力に誘導電動機３の二次時定数Ｔ２を乗算して、加算器１６へ出力する。 In addition, in the pattern generating unit 9A of this embodiment, the differential element 29 is not provided on the output side of the gain 28. Therefore, the gain 28 multiplies the output of the divider 30, the sign of which has been inverted by the gain 31, by the secondary time constant T2 of the induction motor 3, and outputs the result to the adder 16.
　切替接点３２は、積分要素２１に入力される値の切替を行う。パタン生成部９Ａは、通常時制御の実施中はゲイン２０の出力が積分要素２１に入力され、遮断時制御の実施中はゲイン３１の出力が積分要素２１に入力されるように、切替接点３２を切り替える。これにより本実施形態では、第１の実施形態で説明したｄ軸電流指令保持値Ｉｄｐｈの代わりにｄ軸電流指令立下時間Ｔｄを用いて、遮断時の励磁電流指令Ｉｄｐ２および磁化電流指令Ｉ０を算出し、ｄ軸磁束指令φｄｐを求めるようにしている。 The switching contact 32 switches the value input to the integral element 21. The pattern generating unit 9A switches the switching contact 32 so that the output of the gain 20 is input to the integral element 21 during normal control, and the output of the gain 31 is input to the integral element 21 during cutoff control. As a result, in this embodiment, the d-axis current command fall time Td is used instead of the d-axis current command holding value Idph described in the first embodiment to calculate the excitation current command Idp2 and magnetization current command I0 at the time of cutoff, and the d-axis magnetic flux command φdp is obtained.
　また、パタン生成部９Ａは、ゲイン３１により、磁化電流指令保持値Ｉ０ｈをｄ軸電流指令立下時間Ｔｄで割った値の符号を反転する。この処理は、第１の実施形態において微分要素２９が行う磁化電流指令Ｉ０の時間変化率の演算に相当する。すなわち、本実施形態では微分要素２９を用いずに、遮断時の励磁電流指令Ｉｄｐ２を求めることができる。 The pattern generator 9A also uses the gain 31 to invert the sign of the value obtained by dividing the magnetization current command holding value I0h by the d-axis current command fall time Td. This process corresponds to the calculation of the time rate of change of the magnetization current command I0 performed by the differential element 29 in the first embodiment. In other words, in this embodiment, the excitation current command Idp2 at the time of interruption can be obtained without using the differential element 29.
　また、遮断時制御において積分要素２１により、磁化電流指令保持値Ｉ０ｈに対するｄ軸電流指令立下時間Ｔｄの比率を積分するようにしたので、通常時と遮断時とで積分要素２１を共有することができる。そのため、通常時制御から遮断時制御へ遷移するときのｄ軸磁束指令φｄｐの連続性を確実に保証することができる。 In addition, since the integral element 21 is configured to integrate the ratio of the d-axis current command fall time Td to the magnetization current command holding value I0h during interruption control, the integral element 21 can be shared between normal operation and interruption. Therefore, it is possible to reliably guarantee the continuity of the d-axis magnetic flux command φdp when transitioning from normal operation control to interruption control.
　なお、上記の説明では、磁化電流指令保持値Ｉ０ｈに対するｄ軸電流指令立下時間Ｔｄの比率により、遮断時に一定の割合で低下する磁化電流指令Ｉ０を算出しているが、本実施形態ではこの構成に限定する必要はない。例えば、遮断時の磁化電流指令Ｉ０を一定の変化率で立ち下げる変化率リミッタにより、一定の割合で低下する磁化電流指令Ｉ０を実現することも可能である。この場合、変化率リミッタへの入力をゼロから磁化電流指令Ｉ０で減算した値とし、出力を磁化電流指令保持値Ｉ０ｈに対するｄ軸電流指令立下時間Ｔｄの比率で制限することにより、一定の割合で低下する磁化電流指令Ｉ０を実現できる。 In the above explanation, the magnetization current command I0 that decreases at a constant rate when the current is cut off is calculated based on the ratio of the d-axis current command fall time Td to the magnetization current command hold value I0h, but this embodiment does not need to be limited to this configuration. For example, it is possible to realize a magnetization current command I0 that decreases at a constant rate by using a rate of change limiter that causes the magnetization current command I0 at the time of cut off to decrease at a constant rate of change. In this case, the input to the rate of change limiter is set to a value obtained by subtracting the magnetization current command I0 from zero, and the output is limited by the ratio of the d-axis current command fall time Td to the magnetization current command hold value I0h, thereby realizing a magnetization current command I0 that decreases at a constant rate.
　本実施形態の構成によれば、ｄ軸磁束指令の立ち上げ完了前に遮断時制御を実施した場合に、第１の実施形態において図６で説明したのと同様の各指令および状態量とすることが可能である。 　According to the configuration of this embodiment, when cutoff control is performed before the start-up of the d-axis magnetic flux command is complete, it is possible to obtain the same commands and state quantities as those described in FIG. 6 in the first embodiment.
　以上により、本実施形態においても、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に状態遷移した場合に、ｄ軸磁束指令φｄｐを連続してかつ一定レートで立ち下げることができるため、ｄ軸磁束φｄをアンダーシュートすることなくゼロまで減衰させることができる。すなわち、電力変換装置を遮断するときのｄ軸磁束φｄの残留量をゼロにできる。そのため、電力変換装置を再起動させる際の過大な電流やトルクの発生を抑制することができる。 As described above, in this embodiment as well, when the state transition occurs from normal control to cut-off control during the rise of the d-axis magnetic flux command φdp, the d-axis magnetic flux command φdp can be lowered continuously and at a constant rate, so that the d-axis magnetic flux φd can be attenuated to zero without undershooting. In other words, the residual amount of the d-axis magnetic flux φd when the power conversion device is cut off can be made zero. This makes it possible to suppress the generation of excessive current and torque when the power conversion device is restarted.
　また、本実施形態では、第１の実施形態で説明した微分要素２９が不要であるため、例えば遮断時にｄ軸電流指令Ｉｄｐ１が外乱の影響を受けて急変するような場合においても、励磁電流指令Ｉｄｐ２が発散することなく、電力変換装置を安定動作させることができる。 In addition, in this embodiment, the differential element 29 described in the first embodiment is not necessary, so even if the d-axis current command Idp1 suddenly changes due to the influence of a disturbance at the time of interruption, the excitation current command Idp2 does not diverge, and the power conversion device can operate stably.
　以上説明した本発明の第２の実施形態によれば、パタン生成部９Ａは、通常時制御から遮断時制御への切替後に、磁化電流指令保持値Ｉ０ｈを保持し続ける。具体的には、電流指令生成部８は、ｄ軸電流指令Ｉｄｐ１の立ち下げ開始から終了までの時間を表すｄ軸電流指令立下時間Ｔｄを出力する。パタン生成部９Ａは、切替接点２４および遅延要素２５により、通常時制御から遮断時制御への切替直前における磁化電流指令Ｉ０の値を、磁化電流指令保持値Ｉ０ｈとして保持する。また、除算器３０、ゲイン３１および積分要素２１により、磁化電流指令保持値Ｉ０ｈをｄ軸電流指令立下時間Ｔｄで割った値の符号を反転させた値を積算した値を、遮断時制御の実施中における磁化電流指令Ｉ０の値として求める。このようにしたので、第１の実施形態と同様に、ｄ軸磁束指令φｄｐの立ち上げ途中に遮断時制御に遷移しても、連続的に変化する磁化電流指令Ｉ０の値を算出することができる。その結果、ｄ軸磁束φｄをゼロに至るまで一定の変化率で減衰させ、誘導電動機３の内部にｄ軸磁束φｄが残留するのを確実に防止できる。 According to the second embodiment of the present invention described above, the pattern generating unit 9A continues to hold the magnetization current command holding value I0h after switching from normal control to interruption control. Specifically, the current command generating unit 8 outputs the d-axis current command falling time Td, which represents the time from the start to the end of the fall of the d-axis current command Idp1. The pattern generating unit 9A holds the value of the magnetization current command I0 immediately before switching from normal control to interruption control as the magnetization current command holding value I0h using the switching contact 24 and delay element 25. In addition, the divider 30, gain 31, and integral element 21 calculate the value obtained by dividing the magnetization current command holding value I0h by the d-axis current command falling time Td, and then inverting the sign of the value to obtain the value of the magnetization current command I0 during the interruption control. In this way, as in the first embodiment, even if the control transitions to interruption control during the rise of the d-axis magnetic flux command φdp, the value of the magnetization current command I0, which changes continuously, can be calculated. As a result, the d-axis magnetic flux φd is attenuated at a constant rate until it reaches zero, and the d-axis magnetic flux φd is reliably prevented from remaining inside the induction motor 3.
（第３の実施形態）
　次に、本発明の第３の実施形態について説明する。本実施形態では、第１、第２の実施形態に対して、磁化電流指令保持値Ｉ０ｈの保持方法が異なる例を説明する。以下では、第１、第２の実施形態との相違点を中心に説明する。 Third Embodiment
Next, a third embodiment of the present invention will be described. In this embodiment, an example will be described in which a method of holding the magnetization current command holding value I0h is different from that of the first and second embodiments. The following will mainly describe the differences from the first and second embodiments.
　図９は、本発明の第３の実施形態に係るパタン生成部９Ｂの詳細を示す制御ブロック図である。本実施形態のパタン生成部９Ｂは、第１の実施形態で説明した図３のパタン生成部９における切替接点１７、遅延要素１８、切替接点２２、切替接点２４、遅延要素２５、乗算器２６、除算器２７および微分要素２９の代わりに、切替接点３２、最小値リミッタ３３およびゲイン３４を備えて構成される。 FIG. 9 is a control block diagram showing details of a pattern generator 9B according to a third embodiment of the present invention. The pattern generator 9B of this embodiment is configured with a switch contact 32, a minimum limiter 33, and a gain 34, instead of the switch contact 17, delay element 18, switch contact 22, switch contact 24, delay element 25, multiplier 26, divider 27, and differential element 29 in the pattern generator 9 of FIG. 3 described in the first embodiment.
　最小値リミッタ３３は、減算器１９からの出力を上限値０でリミットしてゲイン３４へ出力する。すなわち、減算器１９により求められたｄ軸電流指令Ｉｄｐ１に対する磁化電流指令Ｉ０の差分の大きさが負の値であれば、その値をそのままゲイン３４へ出力し、正の値であれば、上限値０をゲイン３４へ出力する。 The minimum value limiter 33 limits the output from the subtractor 19 to an upper limit value of 0 and outputs it to the gain 34. In other words, if the magnitude of the difference between the d-axis current command Idp1 and the magnetization current command I0 calculated by the subtractor 19 is a negative value, the value is output as is to the gain 34, and if it is a positive value, the upper limit value of 0 is output to the gain 34.
　ゲイン３４は、最小値リミッタ３３の出力に対して、予め設定された誘導電動機３の一次時定数Ｔσの逆数を乗算する。この乗算値は、ゲイン３４から切替接点３２とゲイン２８へ出力される。 Gain 34 multiplies the output of minimum limiter 33 by the inverse of the preset primary time constant Tσ of induction motor 3. This multiplied value is output from gain 34 to switching contact 32 and gain 28.
　なお、本実施形態のパタン生成部９Ｂでは、第２の実施形態におけるパタン生成部９Ａと同様に、ゲイン２８の出力側に微分要素２９が設けられていない。そのため、ゲイン２８は、最小値リミッタ３３により上限値０以下の範囲に制限され、かつ、ゲイン３４により一次時定数Ｔσの逆数が乗算されたｄ軸電流指令Ｉｄｐ１と磁化電流指令Ｉ０の差分に、誘導電動機３の二次時定数Ｔ２を乗算して、加算器１６へ出力する。 In addition, in the pattern generating unit 9B of this embodiment, similar to the pattern generating unit 9A in the second embodiment, the differential element 29 is not provided on the output side of the gain 28. Therefore, the gain 28 is limited to a range equal to or less than the upper limit value 0 by the minimum value limiter 33, and the difference between the d-axis current command Idp1 and the magnetization current command I0 multiplied by the reciprocal of the primary time constant Tσ by the gain 34 is multiplied by the secondary time constant T2 of the induction motor 3 and output to the adder 16.
　また、切替接点３２は、第２の実施形態と同様に、積分要素２１に入力される値の切替を行う。パタン生成部９Ｂは、通常時制御の実施中はゲイン２０の出力が積分要素２１に入力され、遮断時制御の実施中はゲイン３４の出力が積分要素２１に入力されるように、切替接点３２を切り替える。これにより本実施形態では、第１の実施形態で説明したｄ軸電流指令保持値Ｉｄｐｈの代わりに一次時定数Ｔσを用いて、遮断時の励磁電流指令Ｉｄｐ２および磁化電流指令Ｉ０を算出し、ｄ軸磁束指令φｄｐを求めるようにしている。 Also, as in the second embodiment, the switching contact 32 switches the value input to the integral element 21. The pattern generating unit 9B switches the switching contact 32 so that the output of the gain 20 is input to the integral element 21 during normal control, and the output of the gain 34 is input to the integral element 21 during cut-off control. As a result, in this embodiment, the excitation current command Idp2 and magnetization current command I0 during cut-off are calculated using the primary time constant Tσ instead of the d-axis current command holding value Idph described in the first embodiment, and the d-axis magnetic flux command φdp is obtained.
　本実施形態のパタン生成部９Ｂは、通常時は第１の実施形態と同様に、切替接点３２を介して減算器１９、ゲイン２０および積分要素２１により、二次時定数Ｔ２を時定数とした一次遅れとして動作する。一方遮断時には、切替接点３２を介して減算器１９、最小値リミッタ３３、ゲイン３４および積分要素２１により、一次時定数Ｔσを時定数とした入力リミッタ付き一次遅れとして動作する。ここで、遮断時の時定数は、二次時定数Ｔ２に対して十分に短ければよいため、誘導電動機３の一次時定数Ｔσに限定せず、他の時定数を用いてもよい。 The pattern generating unit 9B of this embodiment normally operates as a first-order lag with the secondary time constant T2 as a time constant, as in the first embodiment, through the subtractor 19, gain 20, and integral element 21 via the switching contact 32. On the other hand, during cut-off, it operates as a first-order lag with an input limiter with the primary time constant Tσ as a time constant, through the subtractor 19, minimum value limiter 33, gain 34, and integral element 21 via the switching contact 32. Here, the time constant during cut-off only needs to be sufficiently short compared to the secondary time constant T2, so it is not limited to the primary time constant Tσ of the induction motor 3, and other time constants may be used.
　以上説明したように、本実施形態のパタン生成部９Ｂでは、通常時制御から遮断時制御への切り替えの際に、一次遅れ要素の時定数を二次時定数Ｔ２から一次時定数Ｔσに切り替える。このとき、一次時定数Ｔσは二次時定数Ｔ２に対して十分に短いので、遮断時におけるｄ軸磁束指令φｄｐの立ち下げレートおよび立ち下げ時間は、ｄ軸電流指令Ｉｄｐ１とほぼ一致する。また、一次遅れ要素を構成する積分要素２１により、ｄ軸磁束指令φｄｐの連続性も保たれる。そのため、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に状態遷移した場合でも、ｄ軸磁束指令φｄｐを連続してかつ一定レートで立ち下げることができる。 As described above, in the pattern generation unit 9B of this embodiment, when switching from normal control to interruption control, the time constant of the first-order lag element is switched from the second-order time constant T2 to the first-order time constant Tσ. At this time, since the first-order time constant Tσ is sufficiently short compared to the second-order time constant T2, the fall rate and fall time of the d-axis flux command φdp at the time of interruption almost match the d-axis current command Idp1. In addition, the integral element 21 that constitutes the first-order lag element maintains the continuity of the d-axis flux command φdp. Therefore, even if the state transition occurs from normal control to interruption control during the rise of the d-axis flux command φdp, the d-axis flux command φdp can be continuously fallen at a constant rate.
　さらに、本実施形態のパタン生成部９Ｂでは、ゲイン２８および加算器１６により、ゲイン３４の出力に二次時定数Ｔ２を乗算してｄ軸電流指令Ｉｄｐ１に加算することで、遮断時の励磁電流指令Ｉｄｐ２を求めている。ゲイン３４の出力は磁化電流指令Ｉ０の時間変化率に等しいため、このようにすることで、ｄ軸磁束指令φｄｐの連続動作に必要な励磁電流指令Ｉｄｐ２を演算できる。 Furthermore, in the pattern generating unit 9B of this embodiment, the output of the gain 34 is multiplied by the secondary time constant T2 using the gain 28 and the adder 16, and the result is added to the d-axis current command Idp1 to obtain the excitation current command Idp2 at the time of interruption. Since the output of the gain 34 is equal to the time rate of change of the magnetization current command I0, this makes it possible to calculate the excitation current command Idp2 required for the continuous operation of the d-axis magnetic flux command φdp.
　なお、ｄ軸磁束指令φｄｐの立ち上げ開始から一定値に至る前の状態において、通常時制御から遮断時制御に切り替えると、磁化電流指令Ｉ０よりもｄ軸電流指令Ｉｄｐ１の方が大きい状態で遮断時制御が開始される。このとき、図９に示したパタン生成部９Ｂの構成において仮に最小値リミッタ３３が存在しないと、減算器１９、ゲイン３４および積分要素２１は一次遅れ要素として構成されているので、ｄ軸電流指令Ｉｄｐ１が減少するにも関わらず減算器１９の出力が正となり、その結果、磁化電流指令Ｉ０は、ｄ軸電流指令Ｉｄｐ１とは逆方向である正方向に大きく動作することになる。これでは、遮断時の励磁電流指令Ｉｄｐ２とｄ軸磁束指令φｄｐが過大となり、トルクショックや過電流を引き起こす原因となってしまう。これを防ぐためには、ゲイン３４の入力がゼロ以下になる必要がある。そこで本実施形態のパタン生成部９Ｂでは、ゲイン３４の前段に、減算器１９の出力をゼロ以下の負値に限定してゲイン３４に入力する最小値リミッタ３３が設けられている。 When switching from normal control to interrupt control before the d-axis magnetic flux command φdp reaches a constant value after starting to rise, the interrupt control starts in a state where the d-axis current command Idp1 is greater than the magnetization current command I0. If the minimum value limiter 33 does not exist in the configuration of the pattern generator 9B shown in FIG. 9, the subtractor 19, gain 34, and integral element 21 are configured as first-order lag elements, so that the output of the subtractor 19 becomes positive even though the d-axis current command Idp1 decreases. As a result, the magnetization current command I0 operates largely in the positive direction, which is the opposite direction to the d-axis current command Idp1. This causes the excitation current command Idp2 and the d-axis magnetic flux command φdp at the time of interruption to become excessive, which causes torque shock and overcurrent. To prevent this, the input of the gain 34 needs to be zero or less. Therefore, in the pattern generation unit 9B of this embodiment, a minimum value limiter 33 is provided in front of the gain 34, which limits the output of the subtractor 19 to a negative value less than zero and inputs it to the gain 34.
　図１０は、本発明の第３の実施形態に係る電力変換装置において、ｄ軸磁束指令φｄｐの立ち上げ完了前に遮断時制御を実施した場合の各指令と状態量の一例を示す図である。なお図１０において、図４と同様の動きをする各指令と状態量については、以下で説明を省略する。 FIG. 10 is a diagram showing an example of each command and state quantity when cutoff control is performed before the start-up of the d-axis magnetic flux command φdp is completed in a power conversion device according to a third embodiment of the present invention. Note that in FIG. 10, the commands and state quantities that behave in the same way as in FIG. 4 will not be described below.
　本実施形態の電力変換装置では、図９で示した構成のパタン生成部９Ｂを用いることで、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御への切り替えが発生しても、図１０に示すようにｄ軸磁束指令φｄｐは不連続にならない。また、一次遅れ要素の時定数を二次時定数Ｔ２から一次時定数Ｔσに切り替えることで、遮断時のｄ軸磁束指令φｄｐの上昇を抑えることができる。 In the power conversion device of this embodiment, by using the pattern generation unit 9B configured as shown in FIG. 9, even if a switch from normal control to cutoff control occurs during the rise of the d-axis flux command φdp, the d-axis flux command φdp does not become discontinuous as shown in FIG. 10. In addition, by switching the time constant of the primary lag element from the secondary time constant T2 to the primary time constant Tσ, the increase in the d-axis flux command φdp at cutoff can be suppressed.
　また、遮断時制御において、ｄ軸電流指令Ｉｄｐ１が磁化電流指令Ｉ０よりも大きい期間では、ｄ軸磁束指令φｄｐが一定値で出力され、ｄ軸電流指令Ｉｄｐ１が磁化電流指令Ｉ０と一致した後の期間では、ｄ軸磁束指令φｄｐが一定の変化率で減少する。これにより、ｄ軸電流指令立下時間Ｔｄの期間内にｄ軸磁束指令φｄｐをゼロに至るまで減少させることができる。 In addition, during the cut-off control, in the period when the d-axis current command Idp1 is greater than the magnetization current command I0, the d-axis flux command φdp is output at a constant value, and in the period after the d-axis current command Idp1 matches the magnetization current command I0, the d-axis flux command φdp decreases at a constant rate of change. This makes it possible to decrease the d-axis flux command φdp all the way to zero within the d-axis current command fall time Td.
　以上説明したように、本実施形態の電力変換装置でも、ｄ軸磁束指令φｄｐの立ち上げ途中で通常時制御から遮断時制御に状態遷移した場合に、誘導電動機３における実際のｄ軸磁束φｄを連続して一定の変化率で立ち下げることができるため、ｄ軸磁束φｄをアンダーシュートすることなくゼロまで減衰させることができる。すなわち、電力変換装置を遮断して誘導電動機３の駆動を停止するときのｄ軸磁束φｄの残留量をゼロにできる。そのため、電力変換装置を再起動させる際の過大な電流やトルクの発生を抑制することができる。 As described above, even in the power conversion device of this embodiment, when the state transition occurs from normal control to cut-off control during the rise of the d-axis magnetic flux command φdp, the actual d-axis magnetic flux φd in the induction motor 3 can be continuously lowered at a constant rate of change, so the d-axis magnetic flux φd can be attenuated to zero without undershooting. In other words, the residual amount of d-axis magnetic flux φd can be made zero when the power conversion device is cut off and the drive of the induction motor 3 is stopped. This makes it possible to suppress the generation of excessive current and torque when the power conversion device is restarted.
　以上説明した本発明の第３の実施形態によれば、パタン生成部９Ｂは、積分器である積分要素２１を用いて、ｄ軸電流指令Ｉｄｐ１の立ち下げ開始直前におけるｄ軸磁束指令φｄｐの値に応じた保持値を保持する。具体的には、パタン生成部９Ｂは、減算器１９により、ｄ軸電流指令Ｉｄｐ１と積分要素２１の出力との差分を求める。そして、通常時制御の実施中は、ゲイン２０および切替接点３２により、その差分と二次時定数Ｔ２の逆数との積を積分要素２１に入力したときの積分要素２１の出力を、磁化電流指令Ｉ０として求め、遮断時制御の実施中は、ゲイン３４および切替接点３２により、その差分と二次時定数Ｔ２よりも短い一次時定数Ｔσの逆数との積を積分要素２１に入力したときの積分要素２１の出力を、磁化電流指令Ｉ０として求める。さらに、パタン生成部９Ｂは、遮断時制御の実施中における積分要素２１の入力を０以下の範囲に制限する最小値リミッタ３３を有する。このようにしたので、第１、第２の実施形態と同様に、ｄ軸磁束指令φｄｐの立ち上げ途中に遮断時制御に遷移しても、連続的に変化する磁化電流指令Ｉ０の値を算出することができる。その結果、ｄ軸磁束φｄをゼロに至るまで一定の変化率で減衰させ、誘導電動機３の内部にｄ軸磁束φｄが残留するのを確実に防止できる。 According to the third embodiment of the present invention described above, the pattern generating unit 9B uses the integral element 21, which is an integrator, to hold a holding value corresponding to the value of the d-axis magnetic flux command φdp immediately before the start of the fall of the d-axis current command Idp1. Specifically, the pattern generating unit 9B uses the subtractor 19 to obtain the difference between the d-axis current command Idp1 and the output of the integral element 21. Then, during normal control, the gain 20 and the switching contact 32 obtain the output of the integral element 21 when the product of the difference and the reciprocal of the secondary time constant T2 is input to the integral element 21 as the magnetization current command I0, and during cutoff control, the gain 34 and the switching contact 32 obtain the output of the integral element 21 when the product of the difference and the reciprocal of the primary time constant Tσ, which is shorter than the secondary time constant T2, is input to the integral element 21 as the magnetization current command I0. Furthermore, the pattern generating unit 9B has a minimum value limiter 33 that limits the input of the integral element 21 to a range of 0 or less during cutoff control. In this way, as in the first and second embodiments, even if the control transitions to cutoff control during the rise of the d-axis magnetic flux command φdp, the value of the magnetization current command I0, which changes continuously, can be calculated. As a result, the d-axis magnetic flux φd is attenuated at a constant rate of change until it reaches zero, and the d-axis magnetic flux φd can be reliably prevented from remaining inside the induction motor 3.
　なお、本発明は上記実施形態や変形例に限定されるものではなく、その要旨を逸脱しない範囲内で、任意の構成要素を用いて実施可能である。また、各実施形態や変形例は単独で採用してもよいし、複数を任意に組み合わせて採用することも可能である。すなわち、本発明では各実施形態の特徴同士を任意に組み合わせることで、上述した効果を奏することが可能である。 The present invention is not limited to the above-described embodiments and modifications, and can be implemented using any components without departing from the spirit of the invention. Each embodiment and modification may be used alone, or multiple embodiments and modifications may be used in any combination. In other words, the present invention can achieve the above-described effects by combining the features of each embodiment in any combination.
　上記の実施形態や変形例はあくまで一例であり、発明の特徴が損なわれない限り、本発明はこれらの内容に限定されるものではない。また、上記では種々の実施形態や変形例を説明したが、本発明はこれらの内容に限定されるものではない。本発明の技術的思想の範囲内で考えられるその他の態様も本発明の範囲内に含まれる。 The above embodiments and modifications are merely examples, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. Furthermore, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects that are conceivable within the scope of the technical ideas of the present invention are also included within the scope of the present invention.
　１…電力変換回路、２…制御装置、３…誘導電動機、４…平滑化コンデンサ、５ａ…Ｕ相上アーム素子、５ｂ…Ｕ相下アーム素子、５ｃ…Ｖ相上アーム素子、５ｄ…Ｖ相下アーム素子、５ｅ…Ｗ相上アーム素子、５ｆ…Ｗ相下アーム素子、６…直流電圧センサ、７ａ…Ｕ相電流センサ、７ｂ…Ｖ相電流センサ、７ｃ…Ｗ相電流センサ、８…電流指令生成部、９，９Ａ，９Ｂ…パタン生成部、１０…座標変換部、１１…回転速度推定部、１２…周波数指令生成部、１３…電圧指令生成部、１４…パルス指令生成部、１５…切替接点、１６…加算器、１７…切替接点、１８…遅延要素、１９…減算器、２０…ゲイン、２１…積分要素、２２…切替接点、２３…ゲイン、２４…切替接点、２５…遅延要素、２６…乗算器、２７…除算器、２８…ゲイン、２９…微分要素、３０…除算器、３１…ゲイン、３２…切替接点、３３…最小値リミッタ、３４…ゲイン、Ｅｃｆ…直流電圧、Ｓｕ１…Ｕ相上アームゲートパルス信号、Ｓｕ２…Ｕ相下アームゲートパルス信号、Ｓｖ１…Ｖ相上アームゲートパルス信号、Ｓｖ２…Ｖ相下アームゲートパルス信号、Ｓｗ１…Ｗ相上アームゲートパルス信号、Ｓｗ２…Ｗ相下アームゲートパルス信号、ｉｕ…Ｕ相電流、ｉｖ…Ｖ相電流、ｉｗ…Ｗ相電流、ｃｍｄ…制御指令、Ｉｄｐ１…ｄ軸電流指令、Ｉｄｐ２…励磁電流指令、Ｉｑｐ…ｑ軸電流指令、φｄｐ…ｄ軸磁束指令、Ｉｄｆ…ｄ軸電流検出値、Ｉｑｆ…ｑ軸電流検出値、Ｉ０…磁化電流指令、Ｉｄｐｈ…ｄ軸電流指令保持値、Ｉ０ｈ…磁化電流指令保持値、Ｉｄｐ０…励磁電流指令の定常値、ωｒｅ…ロータ角周波数推定値、ω１…一次角周波数、Ｖｃ…変調率、δ…電圧指令偏角、Ｌ…励磁インダクタンス、Ｔσ…一次時定数、Ｔ２…二次時定数、Ｔｄ…ｄ軸電流指令立下時間 1...power conversion circuit, 2...control device, 3...induction motor, 4...smoothing capacitor, 5a...U-phase upper arm element, 5b...U-phase lower arm element, 5c...V-phase upper arm element, 5d...V-phase lower arm element, 5e...W-phase upper arm element, 5f...W-phase lower arm element, 6...DC voltage sensor, 7a...U-phase current sensor, 7b...V-phase current sensor, 7c...W-phase current sensor, 8...current command generation unit, 9, 9A, 9B...pattern generation unit, 10...coordinate conversion unit, 1 1...rotation speed estimation unit, 12...frequency command generation unit, 13...voltage command generation unit, 14...pulse command generation unit, 15...switching contact, 16...adder, 17...switching contact, 18...delay element, 19...subtractor, 20...gain, 21...integral element, 22...switching contact, 23...gain, 24...switching contact, 25...delay element, 26...multiplier, 27...divider, 28...gain, 29...differential element, 30...divider, 31...gain, 32...switching contact, 33...minimum value limit input, 34...gain, Ecf...DC voltage, Su1...U-phase upper arm gate pulse signal, Su2...U-phase lower arm gate pulse signal, Sv1...V-phase upper arm gate pulse signal, Sv2...V-phase lower arm gate pulse signal, Sw1...W-phase upper arm gate pulse signal, Sw2...W-phase lower arm gate pulse signal, iu...U-phase current, iv...V-phase current, iw...W-phase current, cmd...control command, Idp1...d-axis current command, Idp2...excitation current command command, Iqp...q-axis current command, φdp...d-axis magnetic flux command, Idf...d-axis current detection value, Iqf...q-axis current detection value, I0...magnetization current command, Idph...d-axis current command hold value, I0h...magnetization current command hold value, Idp0...steady-state value of excitation current command, ωre...rotor angular frequency estimate, ω1...primary angular frequency, Vc...modulation rate, δ...voltage command deviation angle, L...excitation inductance, Tσ...primary time constant, T2...secondary time constant, Td...d-axis current command fall time

Claims (20)

  1. 　直流電力を交流電力に変換して誘導電動機を駆動する電力変換回路と、
    　前記電力変換回路にゲートパルス信号を出力して前記電力変換回路を制御する制御装置と、を備えた電力変換装置であって、
    　前記制御装置は、前記ゲートパルス信号の生成に用いられる電流指令および磁束指令を求めるとともに、前記電流指令の立ち下げ開始直前における前記磁束指令の値に応じた保持値を保持可能であり、前記電力変換回路を遮断する際には、前記保持値に基づいて前記電流指令および前記磁束指令を求める電力変換装置。     a power conversion circuit that converts DC power into AC power to drive an induction motor;
    A control device that outputs a gate pulse signal to the power conversion circuit to control the power conversion circuit,
    The control device is capable of determining a current command and a magnetic flux command used in generating the gate pulse signal, and of holding a hold value corresponding to the value of the magnetic flux command immediately before the current command starts to fall, and when shutting off the power conversion circuit, the control device determines the current command and the magnetic flux command based on the hold value.
  2. 　請求項１に記載の電力変換装置であって、
    　前記制御装置には、前記電力変換回路を運転または停止させる制御指令が入力され、
    　前記制御装置は、
    　前記制御指令に基づいて、前記電流指令の立ち下げ開始前の期間に対する通常時制御、または、前記電流指令の立ち下げ開始後の期間に対する遮断時制御のいずれかを実施し、
    　前記通常時制御から前記遮断時制御への切替直前の前記磁束指令の値に応じた前記保持値を保持可能である電力変換装置。     The power conversion device according to claim 1,
    A control command for operating or stopping the power conversion circuit is input to the control device,
    The control device includes:
    Based on the control command, either a normal control for a period before the current command starts to fall or an interruption control for a period after the current command starts to fall is performed;
    A power conversion device capable of holding the held value corresponding to the value of the magnetic flux command immediately before switching from the normal control to the interruption control.
  3. 　請求項２に記載の電力変換装置であって、
    　前記制御装置は、
    　前記制御指令に応じたｄ軸電流指令およびｑ軸電流指令を生成する電流指令生成部と、
    　前記ｄ軸電流指令に基づく励磁電流指令および磁化電流指令を求め、前記磁化電流指令と、前記誘導電動機の特性に応じて予め設定された励磁インダクタンスとに基づいて、前記磁束指令を生成するパタン生成部と、
    　前記励磁電流指令、前記磁束指令および前記ｑ軸電流指令に基づいて電圧指令を生成する電圧指令生成部と、
    　前記電圧指令に基づいて前記ゲートパルス信号を生成するパルス指令生成部と、を有し、
    　前記パタン生成部は、前記通常時制御から前記遮断時制御への切替直前における前記磁化電流指令の値を、前記保持値として保持する電力変換装置。     The power conversion device according to claim 2,
    The control device includes:
    a current command generating unit for generating a d-axis current command and a q-axis current command in accordance with the control command;
    a pattern generating unit that determines an excitation current command and a magnetization current command based on the d-axis current command, and generates the magnetic flux command based on the magnetization current command and an excitation inductance that is preset according to characteristics of the induction motor;
    a voltage command generating unit that generates a voltage command based on the excitation current command, the magnetic flux command, and the q-axis current command;
    a pulse command generating unit that generates the gate pulse signal based on the voltage command,
    The pattern generation unit holds, as the held value, the value of the magnetization current command immediately before switching from the normal control to the interruption control.
  4. 　請求項３に記載の電力変換装置であって、
    　前記パタン生成部は、
    　前記通常時制御の実施中は、前記ｄ軸電流指令から前記励磁電流指令を求めるとともに、前記ｄ軸電流指令と前記誘導電動機の特性に応じて予め設定された二次時定数とに基づいて前記磁化電流指令を求め、
    　前記遮断時制御の実施中は、前記ｄ軸電流指令および前記保持値に基づいて前記磁化電流指令を求めるとともに、前記磁化電流指令および前記二次時定数に基づいて前記励磁電流指令を求める電力変換装置。     The power conversion device according to claim 3,
    The pattern generating unit is
    During the normal operation control, the excitation current command is calculated from the d-axis current command, and the magnetization current command is calculated based on the d-axis current command and a secondary time constant that is preset in accordance with the characteristics of the induction motor;
    The power conversion device determines the magnetization current command based on the d-axis current command and the held value while the interruption control is being performed, and determines the excitation current command based on the magnetization current command and the secondary time constant.
  5. 　請求項４に記載の電力変換装置であって、
    　前記パタン生成部は、前記通常時制御から前記遮断時制御への切替後に、前記保持値を保持し続ける電力変換装置。     The power conversion device according to claim 4,
    The pattern generation unit continues to hold the held value after switching from the normal control to the interruption control.
  6. 　請求項５に記載の電力変換装置であって、
    　前記パタン生成部は、
    　前記通常時制御から前記遮断時制御への切替直前における前記磁化電流指令の値および前記励磁電流指令の値を、第１の保持値および第２の保持値としてそれぞれ保持し、
    　前記ｄ軸電流指令と前記第１の保持値との積を前記第２の保持値で割った値を、前記遮断時制御の実施中における前記磁化電流指令の値として求める電力変換装置。     The power conversion device according to claim 5,
    The pattern generating unit is
    holding a value of the magnetization current command and a value of the excitation current command immediately before switching from the normal control to the interruption control as a first held value and a second held value, respectively;
    The power conversion device determines, as the value of the magnetization current command during the execution of the interruption control, a value obtained by dividing the product of the d-axis current command and the first held value by the second held value.
  7. 　請求項５または６に記載の電力変換装置であって、
    　前記電流指令生成部は、前記電流指令の立ち下げ開始から終了までの時間を表す立下時間を出力し、
    　前記パタン生成部は、
    　前記通常時制御から前記遮断時制御への切替直前における前記磁化電流指令の値を、前記保持値として保持し、
    　前記保持値を前記立下時間で割った値の符号を反転させた値を積算した値を、前記遮断時制御の実施中における前記磁化電流指令の値として求める電力変換装置。     The power conversion device according to claim 5 or 6,
    the current command generating unit outputs a falling time representing a time from a start to an end of a falling edge of the current command;
    The pattern generating unit is
    The value of the magnetization current command immediately before switching from the normal control to the interruption control is held as the held value;
    The power conversion device determines, as the magnetization current command value during the interruption control, a value obtained by dividing the held value by the fall time, inverting the sign of the value, and accumulating the result.
  8. 　請求項４から請求項７のいずれか一項に記載の電力変換装置であって、
    　前記パタン生成部は、積分器を用いて前記保持値を保持する電力変換装置。     The power conversion device according to any one of claims 4 to 7,
    The pattern generating unit is a power conversion device that holds the held value using an integrator.
  9. 　請求項８に記載の電力変換装置であって、
    　前記パタン生成部は、
    　前記ｄ軸電流指令と前記積分器の出力との差分を求め、
    　前記通常時制御の実施中は、前記差分と前記二次時定数の逆数との積を前記積分器に入力したときの前記積分器の出力を、前記磁化電流指令として求め、
    　前記遮断時制御の実施中は、前記差分と前記二次時定数よりも短い一次時定数の逆数との積を前記積分器に入力したときの前記積分器の出力を、前記磁化電流指令として求める電力変換装置。     The power conversion device according to claim 8,
    The pattern generating unit is
    A difference between the d-axis current command and the output of the integrator is calculated.
    During the normal control, a product of the difference and the reciprocal of the secondary time constant is input to the integrator, and an output of the integrator is obtained as the magnetization current command;
    During execution of the cutoff control, the power conversion device determines, as the magnetization current command, the output of the integrator when the product of the difference and the inverse of a primary time constant that is shorter than the secondary time constant is input to the integrator.
  10. 　請求項９に記載の電力変換装置であって、
    　前記パタン生成部は、前記遮断時制御の実施中における前記積分器の入力を０以下の範囲に制限するリミッタを有する電力変換装置。     The power conversion device according to claim 9,
    The pattern generating unit is a power conversion device having a limiter that limits the input of the integrator during execution of the cutoff control to a range equal to or less than 0.
  11. 　直流電力を交流電力に変換して誘導電動機を駆動する電力変換回路の制御方法であって、
    　電流指令および磁束指令を求め、
    　前記電流指令および前記磁束指令に基づいてゲートパルス信号を生成し、
    　前記ゲートパルス信号を前記電力変換回路へ出力し、
    　前記電流指令の立ち下げ開始直前における前記磁束指令の値に応じた保持値を保持し、
    　前記電力変換回路を遮断する際には、前記保持値に基づいて前記電流指令および前記磁束指令を求める電力変換回路の制御方法。     A control method for a power conversion circuit that converts DC power into AC power to drive an induction motor, comprising the steps of:
    Determine the current command and the magnetic flux command,
    generating a gate pulse signal based on the current command and the magnetic flux command;
    outputting the gate pulse signal to the power conversion circuit;
    A hold value corresponding to the value of the magnetic flux command immediately before the current command starts to fall is held;
    A control method for a power conversion circuit, the control method determining the current command and the magnetic flux command based on the held value when the power conversion circuit is shut off.
  12. 　請求項１１に記載の電力変換回路の制御方法であって、
    　前記電力変換回路を運転または停止させる制御指令の入力を受け付け、
    　前記制御指令に基づいて、前記電流指令の立ち下げ開始前の期間に対する通常時制御、または、前記電流指令の立ち下げ開始後の期間に対する遮断時制御のいずれかを実施し、
    　前記通常時制御から前記遮断時制御への切替直前の前記磁束指令の値に応じた前記保持値を保持する電力変換回路の制御方法。     A method for controlling a power conversion circuit according to claim 11, comprising:
    Accepting an input of a control command to operate or stop the power conversion circuit;
    Based on the control command, either a normal control for a period before the current command starts to fall or an interruption control for a period after the current command starts to fall is performed;
    A control method for a power conversion circuit, comprising: holding the held value corresponding to the value of the magnetic flux command immediately before switching from the normal control to the cutoff control.
  13. 　請求項１２に記載の電力変換回路の制御方法であって、
    　前記制御指令に応じたｄ軸電流指令およびｑ軸電流指令を生成し、
    　前記ｄ軸電流指令に基づく励磁電流指令および磁化電流指令を求め、
    　前記磁化電流指令と、前記誘導電動機の特性に応じて予め設定された励磁インダクタンスとに基づいて、前記磁束指令を生成し、
    　前記励磁電流指令、前記磁束指令および前記ｑ軸電流指令に基づいて電圧指令を生成し、
    　前記電圧指令に基づいて前記ゲートパルス信号を生成し、
    　前記通常時制御から前記遮断時制御への切替直前における前記磁化電流指令の値を、前記保持値として保持する電力変換回路の制御方法。     A method for controlling a power conversion circuit according to claim 12, comprising the steps of:
    generating a d-axis current command and a q-axis current command in accordance with the control command;
    determining an excitation current command and a magnetization current command based on the d-axis current command;
    generating the magnetic flux command based on the magnetizing current command and an excitation inductance that is preset according to characteristics of the induction motor;
    generating a voltage command based on the excitation current command, the magnetic flux command, and the q-axis current command;
    generating the gate pulse signal based on the voltage command;
    A control method for a power conversion circuit, comprising: holding, as the held value, the value of the magnetization current command immediately before switching from the normal control to the interruption control.
  14. 　請求項１３に記載の電力変換回路の制御方法であって、
    　前記通常時制御の実施中は、前記ｄ軸電流指令から前記励磁電流指令を求めるとともに、前記ｄ軸電流指令と前記誘導電動機の特性に応じて予め設定された二次時定数とに基づいて前記磁化電流指令を求め、
    　前記遮断時制御の実施中は、前記ｄ軸電流指令および前記保持値に基づいて前記磁化電流指令を求めるとともに、前記磁化電流指令および前記二次時定数に基づいて前記励磁電流指令を求める電力変換回路の制御方法。     A method for controlling a power conversion circuit according to claim 13, comprising the steps of:
    During the normal operation control, the excitation current command is calculated from the d-axis current command, and the magnetization current command is calculated based on the d-axis current command and a secondary time constant that is preset in accordance with the characteristics of the induction motor;
    A control method for a power conversion circuit, the control method comprising: determining the magnetization current command based on the d-axis current command and the held value while the interruption control is being performed; and determining the excitation current command based on the magnetization current command and the secondary time constant.
  15. 　請求項１４に記載の電力変換回路の制御方法であって、
    　前記通常時制御から前記遮断時制御への切替後に、前記保持値を保持し続ける電力変換回路の制御方法。     A method for controlling a power conversion circuit according to claim 14, comprising the steps of:
    A control method for a power conversion circuit, comprising: a step of continuously holding the held value after switching from the normal control to the cutoff control;
  16. 　請求項１５に記載の電力変換回路の制御方法であって、
    　前記通常時制御から前記遮断時制御への切替直前における前記磁化電流指令の値および前記励磁電流指令の値を、第１の保持値および第２の保持値としてそれぞれ保持し、
    　前記ｄ軸電流指令と前記第１の保持値との積を前記第２の保持値で割った値を、前記遮断時制御の実施中における前記磁化電流指令の値として求める電力変換回路の制御方法。     A method for controlling a power conversion circuit according to claim 15, comprising the steps of:
    holding a value of the magnetization current command and a value of the excitation current command immediately before switching from the normal control to the interruption control as a first held value and a second held value, respectively;
    A control method for a power conversion circuit, comprising: determining, as the value of the magnetization current command during execution of the interruption control, a value obtained by dividing the product of the d-axis current command and the first held value by the second held value.
  17. 　請求項１５または１６に記載の電力変換回路の制御方法であって、
    　前記電流指令の立ち下げ開始から終了までの時間を表す立下時間を求め、
    　前記電流指令の立ち下げ開始時における前記磁化電流指令の値に、前記保持値を前記立下時間で割った値の符号を反転させた値を積算した値を、前記遮断時制御の実施中における前記磁化電流指令の値として求める電力変換回路の制御方法。     A method for controlling a power conversion circuit according to claim 15 or 16, comprising the steps of:
    A fall time representing the time from the start to the end of the fall of the current command is obtained;
    A control method for a power conversion circuit that determines, as the value of the magnetization current command during the interruption control, a value obtained by multiplying the value of the magnetization current command at the start of the fall of the current command by a value obtained by dividing the held value by the fall time and inverting the sign of the value.
  18. 　請求項１４から請求項１７のいずれか一項に記載の電力変換回路の制御方法であって、
    　積分器を用いて前記保持値を保持する電力変換回路の制御方法。     A control method for a power conversion circuit according to any one of claims 14 to 17, comprising:
    A method for controlling a power conversion circuit that uses an integrator to hold the held value.
  19. 　請求項１８に記載の電力変換回路の制御方法であって、
    　前記ｄ軸電流指令と前記積分器の出力との差分を求め、
    　前記通常時制御の実施中は、前記差分と前記二次時定数の逆数との積を前記積分器に入力したときの前記積分器の出力を、前記磁化電流指令として求め、
    　前記遮断時制御の実施中は、前記差分と前記二次時定数よりも短い一次時定数の逆数との積を前記積分器に入力したときの前記積分器の出力を、前記磁化電流指令として求める電力変換回路の制御方法。     20. A method for controlling a power conversion circuit according to claim 18, comprising:
    A difference between the d-axis current command and the output of the integrator is calculated.
    During the normal control, a product of the difference and the reciprocal of the secondary time constant is input to the integrator, and an output of the integrator is obtained as the magnetization current command;
    A control method for a power conversion circuit, in which, during execution of the cut-off control, the output of the integrator when the product of the difference and the inverse of a primary time constant that is shorter than the secondary time constant is input to the integrator is obtained as the magnetization current command.
  20. 　請求項１９に記載の電力変換回路の制御方法であって、
    　前記遮断時制御の実施中における前記積分器の入力を０以下の範囲に制限する電力変換回路の制御方法。     20. A method for controlling a power conversion circuit according to claim 19, comprising:
    A control method for a power conversion circuit, comprising: limiting an input to the integrator to a range equal to or less than 0 during execution of the shutdown control.
PCT/JP2023/040591 2022-11-15 2023-11-10 Power converter and method for controlling power converter circuit WO2024106339A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5492178B2 (en) * 2011-12-12 2014-05-14 株式会社東芝 Variable magnetic flux drive system
JP5812476B2 (en) * 2011-08-02 2015-11-11 学校法人 東洋大学 Permanent magnet rotating electric machine and its operating method
JP6410939B2 (en) * 2015-07-10 2018-10-24 三菱電機株式会社 Motor control device, compressor, and air conditioner

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5812476B2 (en) * 2011-08-02 2015-11-11 学校法人 東洋大学 Permanent magnet rotating electric machine and its operating method
JP5492178B2 (en) * 2011-12-12 2014-05-14 株式会社東芝 Variable magnetic flux drive system
JP6410939B2 (en) * 2015-07-10 2018-10-24 三菱電機株式会社 Motor control device, compressor, and air conditioner

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