CN113574791B - Power conversion device, drive control system, machine learning device, and motor monitoring method - Google Patents

Power conversion device, drive control system, machine learning device, and motor monitoring method Download PDF

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Publication number
CN113574791B
CN113574791B CN201980093995.1A CN201980093995A CN113574791B CN 113574791 B CN113574791 B CN 113574791B CN 201980093995 A CN201980093995 A CN 201980093995A CN 113574791 B CN113574791 B CN 113574791B
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current
unit
frequency
motor
current frequency
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CN113574791A (en
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服部宪和
铃木规央
田中哲夫
法名直人
原田崇弘
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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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
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/14—Electronic commutators
    • H02P6/16—Circuit arrangements for detecting position
    • H02P6/18—Circuit arrangements for detecting position without separate position detecting elements
    • 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
    • H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
    • H02P29/02—Providing protection against overload without automatic interruption of supply
    • H02P29/032—Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
    • 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
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/08—Arrangements for controlling the speed or torque of a single motor

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)
  • Control Of Electric Motors In General (AREA)
  • Inverter Devices (AREA)

Abstract

The power conversion device has a main circuit unit, a control unit (12), a current sensor, and a half-wave rectifier unit. The control unit (12) has current frequency calculation units (42, 51) and monitoring units (43, 52). The current frequency calculation units (42, 51) calculate the current frequency (omega) based on at least one of the rising timing and the falling timing of the current detection signal half-wave rectified by the half-wave rectification unit c1 、ω c2 ) And (4) performing calculation. The monitoring units (43, 52) calculate the current frequency (omega) based on the current frequency (42, 51) c1 、ω c2 ) The speed of the motor is monitored.

Description

Power conversion device, drive control system, machine learning device, and motor monitoring method
Technical Field
The present invention relates to a power conversion device, a drive control system, a machine learning device, and a motor monitoring method for supplying electric power to a motor.
Background
In recent years, a power conversion device for supplying electric power to a motor is required to meet functional safety standards such as IEC (International electrical Commission) 61508 or ISO (International Organization for Standardization) 13849, which are International standards. In particular, the power conversion apparatus is required to comply with a safe Speed monitoring (SLS) which is one of functional Safety specifications.
The safe speed monitoring is a function of monitoring that a predetermined speed limit value is not exceeded. In the power conversion device corresponding to the safe speed monitoring, when the speed of the motor exceeds a predetermined speed limit value, the gate drive signal of the power conversion device is turned off to stop the power supply to the motor, thereby ensuring safety.
In such a power conversion device, when the speed of the motor is monitored using an external detector such as an encoder, the cost increases, or the connection wiring of the external detector becomes complicated. Therefore, a technique for monitoring the speed of the motor based on the current value detected by the current sensor has been proposed for the power conversion device. For example, patent document 1 discloses a technique of detecting a current value, which is a value of a current supplied to a motor by a current sensor, and monitoring a speed of the motor based on the current value.
Patent document 1: international publication No. 2016/051552
Disclosure of Invention
However, patent document 1 only describes monitoring the speed of the motor based on the current value detected by the current sensor, and does not propose a specific process.
The present invention has been made in view of the above problems, and an object of the present invention is to obtain a power conversion device capable of monitoring a safe speed with a simple configuration using a current sensor.
In order to solve the above problems and achieve the object, a power conversion device according to the present invention includes: a main circuit unit that converts dc power into ac power and supplies the converted ac power to a motor; a control unit for controlling the main circuit unit; a current sensor that detects a current supplied from the main circuit unit to the motor; and a half-wave rectification unit that half-wave rectifies a current detection signal output from the current sensor. The control unit includes: a current frequency calculation unit that calculates a current frequency that is a frequency of the current based on at least one of a rising timing and a falling timing of the current detection signal half-wave rectified by the half-wave rectification unit; and a monitoring unit that monitors the speed of the motor based on the current frequency calculated by the current frequency calculation unit.
ADVANTAGEOUS EFFECTS OF INVENTION
The power conversion device according to the present invention has an effect that safe speed monitoring can be performed with a simple configuration using a current sensor.
Drawings
Fig. 1 is a diagram showing a configuration example of a drive control system including a power conversion device according to embodiment 1 of the present invention.
Fig. 2 is a diagram showing a configuration example of a control unit, a gate drive unit, and a zero cross detection unit in the power conversion device according to embodiment 1.
Fig. 3 is a diagram showing a configuration example of the current sign signal generating unit according to embodiment 1.
Fig. 4 is a diagram showing a relationship between a current detection signal output from the current sensor according to embodiment 1, a current detection signal half-wave rectified by the half-wave rectification section, and a current sign signal.
Fig. 5 is a flowchart showing an example of processing of the drive control unit of the control unit according to embodiment 1.
Fig. 6 is a diagram showing an example of the hardware configuration of the gate driving unit, the zero-crossing detection unit, the drive control unit, and the safety function unit according to embodiment 1.
Fig. 7 is a diagram showing a configuration example of a drive control system including the power conversion device according to embodiment 2.
Fig. 8 is a diagram showing a configuration example of a current frequency calculating unit according to embodiment 2.
Fig. 9 is a diagram showing an example of the 3-layer neural network according to embodiment 2.
Fig. 10 is a diagram showing another configuration example of a drive control system including the power conversion device according to embodiment 2.
Fig. 11 is a diagram showing a configuration example of the machine learning device according to embodiment 2.
Detailed Description
Hereinafter, a power conversion device, a drive control system, a machine learning device, and a motor monitoring method according to embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiment.
Embodiment 1.
Fig. 1 is a diagram showing a configuration example of a drive control system including a power conversion device according to embodiment 1 of the present invention. As shown in fig. 1, a drive control system 100 according to embodiment 1 includes a power conversion device 1, a motor 2, an ac power supply 3, and a safety device 4.
The power converter 1 operates by ac power supplied from an ac power supply 3, and controls and drives the motor 2. The power conversion device 1 converts 3-phase ac power supplied from an ac power supply 3 into ac power having a frequency corresponding to a command signal input from the outside, and supplies the ac power to the motor 2. For example, when the motor 2 is a 3-phase ac motor, the power conversion device 1 can convert 3-phase ac power supplied from the ac power supply 3 into 3-phase ac power having a frequency corresponding to the command signal, and supply the 3-phase ac power to the motor 2. Further, the alternating current power supply 3 may be a single-phase power supply.
The safety device 4 outputs a safety signal for bringing the motor 2 into a safe state to the power conversion device 1 in the drive control system 100. The types of safety signals include, for example, a signal requesting Safe Torque Off (STO: safe Torque Off), a signal requesting Safe Stop 1 (SS 1: safe Stop 1), and a signal requesting Safe speed monitoring (SLS). Hereinafter, a signal requesting safe torque off may be referred to as an STO signal, a signal requesting safe stop 1 may be referred to as an SS1 signal, and a signal requesting safe speed monitoring may be referred to as an SLS signal.
The STO signal is a signal that requests the power conversion device 1 to stop the supply of electric power from the power conversion device 1 that drives the motor 2 to the motor 2. The SS1 signal is a signal that requests the power conversion device 1 to stop the supply of electric power to the motor 2 by the safe torque off after a predetermined time has elapsed after the start of deceleration of the motor 2. The SLS signal is a signal requesting the power conversion device 1 to monitor that the speed of the motor 2 does not exceed a predetermined speed limit value, and to stop the supply of electric power to the motor 2 by turning off the safety torque when the speed of the motor 2 exceeds the predetermined speed limit value. The STO signal, SS1 signal, and SLS signal are signals requesting, for example, execution of a safety function specified by International Specification IEC 61508-5-1.
The safety device 4 outputs a safety signal to the power converter 1, for example, when detecting that an operator approaches the motor 2 or when operating an emergency stop button. The safety device 4 is, for example, a safety PLC (Programmable Logic Controller) or a safety relay. The safety device 4 is connected to a plurality of devices such as a detection device for detecting, for example, approach of an operator to the motor 2 and an emergency stop button, and outputs a safety signal when receiving a notification of the emergency from any one of the devices.
The power conversion device 1 includes a main circuit unit 11, a control unit 12, a gate drive unit 13, a current sensor 14, and a zero-crossing detection unit 15. The main circuit unit 11 supplies ac power for driving the motor 2 to the motor 2 based on the 3-phase ac power supplied from the ac power supply 3. The main circuit part 11 has an AC/DC converter 20 and a DC/AC converter 21.
The AC/DC converter 20 converts AC power supplied from the AC power supply 3 into DC power. The AC/DC converter 20 includes a 3-phase diode bridge 22 formed of a plurality of diodes connected in a 3-phase bridge, and a smoothing capacitor 23 for smoothing an AC voltage rectified by the 3-phase diode bridge 22. The AC/DC converter 20 may have a configuration in which a plurality of switching elements connected in a 3-phase bridge are provided instead of the 3-phase diode bridge 22.
The DC/AC converter 21 converts the DC power supplied from the AC/DC converter 20 into AC power having a frequency corresponding to the command signal, and outputs the converted AC power to the motor 2. The DC/AC converter 21 has a plurality of switching elements 31, 32, 33, 34, 35, 36 connected in a 3-phase bridge. The switching elements 31, 32, 33, 34, 35, and 36 may be Semiconductor switching elements such as MOSFETs (Metal Oxide Semiconductor Field Effect transistors) or IGBTs (Insulated Gate Bipolar transistors), for example.
The control unit 12 includes a drive control unit 40 and a safety function unit 50, the drive control unit 40 monitoring abnormality and the like while generating a control signal for driving the motor 2, and the safety function unit 50 monitoring abnormality and the like. As will be described later, the drive control unit 40 and the safety function unit 50 repeatedly process the safety signal to make it redundant.
The drive control unit 40 generates a control signal based on, for example, an instruction signal input from the outside, and outputs the generated control signal to the gate drive unit 13. The command signal is, for example, a signal indicating a speed command for specifying the speed of the motor 2. When the command signal is a speed command, the drive control unit 40 generates a control signal for setting the speed of the motor 2 to a speed corresponding to the speed command, and outputs the generated control signal to the gate drive unit 13.
The drive control unit 40 generates a control signal based on the safety signal output from the safety device 4, and outputs the generated control signal to the gate drive unit 13. For example, when the safety signal output from the safety device 4 is the SLS signal, the drive control unit 40 controls the motor 2 so that the speed of the motor 2 does not exceed the predetermined speed limit value, and at the same time, controls the motor 2 based on the current sign signal I output from the zero-cross detection unit 15 sig1 For the speed of the motor 2 not exceeding a predetermined speed limit valueThis situation is monitored. When the speed of the motor 2 exceeds the predetermined speed limit value, the drive control unit 40 outputs a control signal for turning off the switching elements 31, 32, 33, 34, 35, and 36 to the gate drive unit 13.
The safety function unit 50 controls the drive control unit 40 based on a safety signal output from the safety device 4. For example, when the safety signal output from the safety device 4 is the SLS signal, the safety function unit 50 is based on the current sign signal I output from the zero-crossing detector 15 sig2 And monitors that the speed of the motor 2 does not exceed a predetermined speed limit value. When the speed of the motor 2 exceeds the predetermined speed limit value, the safety function unit 50 causes the drive control unit 40 to execute a function of shutting off the safety torque.
The gate driving unit 13 generates a plurality of PWM (Pulse Width Modulation) signals for driving the switching elements 31, 32, 33, 34, 35, and 36 based on a control signal output from the drive control unit 40. The gate driver 13 outputs the generated PWM signals to corresponding ones of the switching elements 31, 32, 33, 34, 35, and 36. The PWM signals drive the gates of the switching elements 31, 32, 33, 34, 35, 36, and are therefore also referred to as gate drive signals.
The current sensor 14 detects an alternating current supplied from the main circuit unit 11 to the motor 2, and outputs a current detection signal I representing an analog waveform of the alternating current supplied from the main circuit unit 11 to the motor 2 det . When the motor 2 is a 3-phase ac motor, the current sensor 14 outputs a current detection signal I indicating an analog waveform of an ac current supplied to 1 of the 3 phases det 。
The current sensor 14 is a hall element type current sensor including a magnetic core, a hall element, an operational amplifier, and the like, for example. The current sensor 14 converts a magnetic field generated around a conductor line for supplying a drive current from the main circuit unit 11 to the motor 2 into a voltage by using the hall effect, and uses the converted voltage as a current detection signal I det And output. In addition, the current sensor 14 may include, for example, a magnetic core, a secondary windingAnd a Current sensor of a CT (Current Transformer) type such as a resistor. The current sensor 14 may include a shunt resistor connected in series between the main circuit unit 11 and the motor 2.
Zero-crossing detector 15 detects signal I based on the current output from current sensor 14 det To generate a current sign signal I sig1 、I sig2 . Then, the zero-crossing detector 15 outputs the current sign signal I sig1 Outputs the current sign signal I to the drive control unit 40 sig2 And outputs the result to the safety function section 50. Sign signal of current I sig1 、I sig2 The time-series sample column signal includes information indicating the sign of the drive current obtained by sampling the waveform of the drive current supplied from the main circuit unit 11 to the motor 2 on the basis of the time series.
Next, a configuration example of the power conversion device 1 that executes processing in a case where the safety signal output from the safety device 4 is an SLS signal will be described. Fig. 2 is a diagram showing a configuration example of a control unit, a gate drive unit, and a zero cross detection unit of the power conversion device according to embodiment 1.
As shown in fig. 2, the zero-crossing detector 15 includes current symbol signal generators 61 and 62. The current sign signal generating section 61 generates a current detection signal I based on the current sensor 14 det To generate a current symbol signal I sig1 . Similarly, the current sign signal generating section 62 generates the current detection signal I based on the current output from the current sensor 14 det To generate a current symbol signal I sig2 . The current sign signal generating section 61 and the current sign signal generating section 62 have the same configuration.
Fig. 3 is a diagram showing a configuration example of the current sign signal generating unit according to embodiment 1. As shown in fig. 3, the current sign signal generating section 61 has a half-wave rectifying section 80, an operational amplifier 81, a filter 82, and a hysteresis comparator 83.
Half-wave rectification unit 80 detects current detection signal I output from current sensor 14 det Performing half-wave rectification, and outputting a half-wave rectified current detection signal I det I.e. current detectionSignal I detr . The half-wave rectification section 80 is formed of a diode, for example.
Operational amplifier 81 detects current I output from half-wave rectifier 80 detr And amplifying the voltage and outputting the amplified voltage. The filter 82 detects the current I amplified by the voltage of the operational amplifier 81 detr The noise removal of (2). The filter 82 is, for example, an RC low-pass filter. Further, the filter 82 may be a band pass filter.
The hysteresis comparator 83 detects the current I output from the filter 82 detr Detects the rising timing and the falling timing of the reference voltage, and outputs a current symbol signal I which is a signal indicating the detection result sig1 . Operational amplifier 81, filter 82, and hysteresis comparator 83 are configured to detect current I as a half-wave rectified waveform detr And (6) processing. Therefore, the operational amplifier 81, the filter 82, and the hysteresis comparator 83 can be driven by a single power supply without requiring a negative power supply. Therefore, the current sign signal generating unit 61 can be configured to be simple.
The hysteresis comparator 83 has a comparator 91 and resistors 92, 93, 94, 95, and 96. The hysteresis comparator 83 detects the current I in the current detection signal detr When the sign inversion threshold Th1 is greater than or equal to, the current sign signal I is set sig1 At a high level, at a current detection signal I detr When the sign inversion threshold Th2 is smaller than or equal to, the current sign signal I is set sig1 Is a low bit level. Th1 > Th2.
Fig. 4 is a diagram showing a relationship between a current detection signal output from the current sensor according to embodiment 1, a current detection signal half-wave rectified by the half-wave rectifier, and a current sign signal. As shown in fig. 4, the current detection signal I det Half-wave rectification is performed by the half-wave rectification section 80, and the half-wave rectified current detection signal I is detected detr And outputs the delayed signal to the hysteresis comparator 83.
The hysteresis comparator 83 detects the current I output from the half-wave rectifier 80 detr The rising timing and the falling timing of (c) are detected. For example, the hysteresis comparator 83 detects the current I detr Become largeTiming-to-current detection signal I equal to or greater than sign inversion threshold Th1 detr Is detected so that the current sign signal I is detected sig1 Changing from a low level to a high level. In addition, the hysteresis comparator 83 detects the current I in the current detection signal detr Timing to current detection signal I becoming less than or equal to sign inversion threshold Th2 detr Is detected so that the current sign signal I is detected sig1 Changing from a high bit level to a low bit level.
The hysteresis comparator 83 does not detect the ripple of the drive current smaller than the difference between the sign inversion threshold Th1 and the sign inversion threshold Th2, and has high noise resistance. Therefore, the current sign signal generating unit 61 can have a simple configuration for the filter 82. The current sign signal generating units 61 and 62 are not limited to the configuration shown in fig. 3. For example, the signal I may not be detected for the current det When the voltage amplification is performed, the current sign signal generating units 61 and 62 may not be provided with the operational amplifier 81.
The hysteresis comparator 83 is not limited to the configuration shown in fig. 3. For example, the hysteresis comparator 83 may be configured such that the current detection signal I is detected detr When the sign of the current signal I is equal to or greater than the sign inversion threshold Th1 sig1 At a low level, at a current detection signal I detr When the current sign signal I becomes less than or equal to a sign inversion threshold Th2 sig1 Is high level. In addition, the relationship between the symbol inversion threshold value Th1 and the symbol inversion threshold value Th2 may be Th1 < Th2. In addition, the hysteresis comparator 83 may be a digital circuit instead of an analog circuit.
Returning to fig. 2, the description of the control unit 12 is continued. As shown in fig. 2, the control unit 12 includes a drive control unit 40 and a safety function unit 50. The drive control unit 40 includes a control signal generation unit 41, a current frequency calculation unit 42, and a monitoring unit 43.
The control signal generating unit 41 generates a control signal based on a command signal input from the outside or a safety signal input from the safety device 4. The power converter 1 is provided with a current sensor, not shown, which is a current sensor different from the current sensor 14 and detects the 3-phase current supplied to the motor 2. The control signal generating unit 41 includes a speed control unit, not shown, for performing speed control based on the 3-phase current detected by the current sensor, and a current control unit, not shown, for performing current control based on the 3-phase current detected by the current sensor.
The speed control unit, not shown, can estimate the speed of the motor 2 based on, for example, the 3-phase current detected by the current sensor, and generate the current command so that the estimated speed of the motor 2 matches the speed command. The current control unit, not shown, can generate a control signal so that the q-axis current in the dq coordinate system obtained from the 3-phase current detected by the current sensor matches the current command.
The current frequency calculating section 42 calculates the current symbol signal I based on the current symbol signal I output from the zero-cross detecting section 15 sig1 And a current frequency omega which is the frequency of the current supplied from the main circuit part 11 to the motor 2 c1 And (4) performing calculation. Specifically, the current frequency calculating section 42 has a pulse counting function and counts the current symbol signal I sig1 The two edges of rise and fall are counted. The current frequency calculation unit 42 samples the count value at a predetermined cycle, and calculates the current frequency ω from the sampled count value c1 And (4) performing calculation. In addition, the current frequency calculating unit 42 may be based on the current sign signal I instead of the current sign signal I sig1 Is counted together with the rise and fall of (c) and the current frequency omega is counted c1 The calculation is performed, but the structure is such that the symbol signal I is based on the convection only symbol signal I sig1 Is counted as a result of the rise or fall of the current frequency ω c1 And (4) performing calculation.
The monitoring unit 43 calculates the current frequency ω from the current frequency calculated by the current frequency calculating unit 42 c1 The speed of the motor 2 is monitored, and based on the monitoring result, it is determined whether, for example, safe torque shutdown is to be executed. Specifically, the monitoring unit 43 monitors the current frequency ω calculated by the current frequency calculating unit 42 c1 If it is determined that the control unit 12 does not control the motor 2 in accordance with the safety signal,the control signal generation section 41 is caused to execute the safe torque off. The monitoring section 43 has a current frequency self-diagnosis section 44, a current frequency mutual diagnosis section 45, and an output frequency self-diagnosis section 46.
The current frequency self-diagnosis unit 44 calculates the current frequency ω from the current frequency calculation unit 42 c1 Or with the current frequency omega c1 The proportional value is the speed of the motor 2, and the speed of the motor 2 is less than or equal to a predetermined speed limit value ω th And (6) judging. The current frequency self-diagnosis unit 44 determines the current frequency ω c1 Or with the current frequency omega c1 The proportional value is not less than or equal to the prescribed speed limit value omega th In the case of (3), the control signal generation unit 41 is caused to output a control signal for executing the safe torque off to the gate drive unit 13.
In addition, the current frequency ω c1 Is a value proportional to the speed of the motor 2 corresponding to the number of stator poles in the motor 2, and can be treated as an estimated value of the speed of the motor 2. The current frequency self-diagnosis section 44 performs self-diagnosis on the current frequency ω c1 Whether or not it is less than or equal to a prescribed speed limit value omega th When the determination is made, the speed limit value ω is defined th Is a limit value corresponding to the speed of the motor 2 corresponding to the number of stator poles in the motor 2. In addition, with the current frequency omega c1 A value proportional to, for example, the frequency ω of the current c1 The value obtained by dividing the value obtained by multiplying 2 by the number of stator poles in the motor 2 can be used as the speed [ rps ] of the motor 2]And processes the estimated value of (a). The current frequency self-diagnosis unit 44 is configured to diagnose the current frequency ω c1 Whether or not the proportional value is less than or equal to a prescribed speed limit value omega th When the determination is made, the speed limit value ω is defined th Is related to the speed [ rps ] of the motor 2]The corresponding upper limit value.
The gate driving unit 13 includes a PWM signal generating unit 71 that generates PWM signals to be output to the switching elements 31, 32, 33, 34, 35, and 36 based on the control signal output from the control signal generating unit 41. When the control signal for executing the safe torque off is output from the control signal generating unit 41, the PWM signal generating unit 71 turns off the PWM signals to the switching elements 31, 32, 33, 34, 35, and 36. Thereby, the supply of electric power from the main circuit unit 11 to the motor 2 is stopped.
The current frequency self-diagnosis unit 44 determines the current frequency ω c1 Or with the current frequency omega c1 The proportional value is not less than or equal to the prescribed speed limit value omega th In the case of (3), an alarm can be displayed on the display 16. The Display 16 is a Display such as an LCD (Liquid Crystal Display) or an alarm lamp. The current frequency self-diagnosis unit 44 can display the current frequency ω when the display 16 is an LCD c1 Or with the current frequency omega c1 The proportional value is not less than or equal to the prescribed speed limit value omega th The display 16 displays text information and the like of the content. In addition, the current frequency self-diagnosis unit 44 may also be configured to display the current frequency ω c1 Or with the current frequency omega c1 Time offset of the proportional value and the prescribed speed limit value omega th Is shown on the display 16. The current frequency self-diagnosis unit 44 determines the current frequency ω c1 Or with the current frequency omega c1 The proportional value is not less than or equal to the prescribed speed limit value omega th In this case, the alarm sound may be outputted from a speaker, not shown.
The current frequency self-diagnosis unit 44 determines the current frequency ω c1 Or with the current frequency omega c1 The proportional value is not less than or equal to the prescribed speed limit value omega th In the case of (3), the control signal generation unit 41 may be configured to output a control signal for reducing the supply of electric power to the motor 2 to the gate drive unit 13 instead of the control signal for executing the safety torque off. This can reduce the electric power supplied to the motor 2.
The current frequency mutual diagnosing section 45 bases on the current frequency ω calculated by the current frequency calculating section 42 c1 And a current frequency ω calculated by the safety function unit 50 and described later c2 And mutual judgment processing is performed. Specifically, the current frequency mutual diagnosing section 45 diagnoses the current frequency ω c1 With current frequency omega c2 Whether the difference is atWithin a predetermined range R set in advance th1 And (4) internally judging. The current frequency mutual diagnostic unit 45 determines the current frequency ω c1 With current frequency omega c2 The difference is within a predetermined range R th1 Otherwise, the control signal generating unit 41 is caused to output a control signal for executing the safe torque off to the gate driving unit 13. Thereby, the supply of electric power to the motor 2 is stopped.
The output frequency self-diagnosis unit 46 compares the current frequency ω calculated by the current frequency calculation unit 42 with the output frequency c1 And the output frequency ω calculated by the gate driving section 13 out Whether the difference is within a predetermined range R th2 And (4) internally judging. The gate driving section 13 has a frequency of output ω out The calculated output frequency calculating unit 72, and the output frequency self-diagnosing unit 46 obtains the output frequency ω calculated by the output frequency calculating unit 72 from the output frequency calculating unit 72 out The information of (a).
Output frequency omega out Is the frequency of the drive voltage output from the DC/AC converter 21 of the main circuit unit 11 to the motor 2 in accordance with the control of the gate drive signals of the switching elements 31, 32, 33, 34, 35, and 36. The output frequency calculation unit 72 outputs the output frequency ω to the output frequency ω based on the control signal generated by the control signal generation unit 41 out And (6) performing calculation. For example, when the control signal includes a voltage command of 3-phase coordinates, the frequency of the voltage command can be set as the output frequency ω out And the calculation is performed.
The output frequency self-diagnosis unit 46 determines the current frequency ω c1 And the output frequency omega out The difference is in a predetermined range R th2 Otherwise, the control signal generation unit 41 is caused to output a control signal for executing the safe torque off to the gate drive unit 13. Thereby, the supply of electric power to the motor 2 is stopped.
Similarly to the current frequency self-diagnosis unit 44, the current frequency mutual-diagnosis unit 45 and the output frequency self-diagnosis unit 46 can display an alarm on the display 16 or output an alarm sound from a speaker, not shown, when the control signal generation unit 41 is caused to execute the safe torque off. Similarly to the current frequency self-diagnosis unit 44, the current frequency mutual-diagnosis unit 45 and the output frequency self-diagnosis unit 46 may be configured to cause the control signal generation unit 41 to output a control signal for reducing the supply of electric power to the motor 2 to the gate drive unit 13 instead of the control signal for executing the safe torque off.
The safety function unit 50 includes a current frequency calculation unit 51 and a monitoring unit 52. The current frequency calculating section 51 calculates the current symbol signal I based on the current symbol signal I outputted from the zero-cross detecting section 15 sig2 And a current frequency omega which is the frequency of the current supplied from the main circuit part 11 to the motor 2 c2 And (4) performing calculation. The current frequency calculating section 51 has a pulse counting function, similarly to the current frequency calculating section 42, and counts the current symbol signal I sig2 The two edges of rise and fall are counted. The current frequency calculation unit 51 samples the count value at a predetermined cycle, and based on the sampled count value, calculates the current frequency ω c2 The speed of the motor 2 is calculated. In addition, the current frequency calculating unit 51 may be based on the current sign signal I instead of the current sign signal I sig2 Is counted together with the rise and fall of the current frequency omega c2 The calculation is carried out, but the structure is that based on the sign signal I of the current only sig2 Is counted as a result of the rise or fall of (c) to the current frequency ω c2 And (4) performing calculation.
The monitoring unit 52 calculates the current frequency ω from the current frequency calculated by the current frequency calculating unit 51 c2 And determines whether a safe torque shut-off can be performed. Specifically, the monitoring unit 52 calculates the current frequency ω based on the current frequency ω calculated by the current frequency calculating unit 51 c2 On the other hand, if it is determined that the control unit 12 does not control the motor 2 in accordance with the safety signal, the control signal generation unit 41 is caused to execute the safety torque off. The monitoring unit 52 includes a current frequency self-diagnosis unit 53, a current frequency mutual diagnosis unit 54, and an output frequency self-diagnosis unit 55.
The current frequency self-diagnosis unit 53 compares the current frequency ω calculated by the current frequency calculation unit 51 with the current frequency ω c2 Or with the current frequency omega c2 The proportional value is the speed of the motor 2, and the speed of the motor 2 is less than or equal to a predetermined speed limit value ω th And (6) judging. The current frequency self-diagnosis unit 53 determines the current frequency ω c2 Or with the current frequency omega c2 The proportional value is not less than or equal to the prescribed speed limit value omega th In the case of (3), the control signal generation unit 41 is caused to output a control signal for executing the safe torque off to the gate drive unit 13. Thereby, the supply of electric power to the motor 2 is stopped.
In addition, the current frequency self-diagnosis unit 53 determines the current frequency ω as the current frequency self-diagnosis unit 44 does c2 Or with the current frequency omega c2 The proportional value is not less than or equal to the prescribed speed limit value omega th In the case of (3), an alarm can be displayed on the display 16 or an alarm sound can be output from a speaker not shown. In addition, the current frequency self-diagnosis unit 53 determines the current frequency ω, similarly to the current frequency self-diagnosis unit 44 c2 Or with the current frequency omega c2 The proportional value is not less than or equal to the prescribed speed limit value omega th In the case of (3), the control signal generation unit 41 can be caused to output a control signal for reducing the supply of electric power to the motor 2 to the gate drive unit 13 instead of the control signal for executing the safety torque off.
In addition, the current frequency ω c2 Is a value proportional to the speed of the motor 2 corresponding to the number of stator poles in the motor 2, and is proportional to the current frequency ω c1 Similarly, the speed of the motor 2 can be processed as an estimated value. The current frequency self-diagnosis section 53 performs the self-diagnosis on the current frequency ω c2 Whether or not it is less than or equal to a prescribed speed limit value omega th When the determination is made, the speed limit value ω is defined th Is a limit value corresponding to the speed of the motor 2 corresponding to the number of stator poles in the motor 2. In addition, with the current frequency omega c2 A value proportional to, for example, the frequency ω of the current c2 The value obtained by dividing the value obtained by multiplying 2 by the number of stator poles in the motor 2 can be used as the speed [ rps ] of the motor 2]And processes the estimated value of (a). The current frequency self-diagnosis unit 53 is configured to make a correlation with the current frequency ω c2 Whether or not the proportional value is less than or equal to a prescribed speed limit value omega th In the case of making a determinationSpecifying a speed limit value omega th Is related to the speed [ rps ] of the motor 2]The corresponding upper limit value.
The current frequency mutual diagnosing unit 54 is based on the current frequency ω, similarly to the current frequency mutual diagnosing unit 45 c1 、ω c2 And mutual judgment processing is performed. Specifically, the current frequency mutual diagnosing section 54 determines the current frequency ω c1 With current frequency omega c2 Whether the difference is within a predetermined range R th1 And (4) internally judging. The current frequency mutual diagnostic unit 54 determines the current frequency ω c1 With current frequency omega c2 The difference is in a predetermined range R th1 Otherwise, the control signal generation unit 41 is caused to output a control signal for executing the safe torque off to the gate drive unit 13. Thereby, the supply of electric power to the motor 2 is stopped.
Output frequency self-diagnosis unit 55 for current frequency ω c2 And the output frequency omega out Whether the difference is within a predetermined range R th2 And (4) internally judging. The output frequency self-diagnosis unit 55 determines the current frequency ω c2 And the output frequency omega out The difference is in a predetermined range R th2 Otherwise, the control signal generation unit 41 is caused to output a control signal for executing the safe torque off to the gate drive unit 13. Thereby, the supply of electric power to the motor 2 is stopped.
Similarly to the current frequency self-diagnosis unit 53, the current frequency mutual diagnosis unit 54 and the output frequency self-diagnosis unit 55 can display an alarm on the display 16 or output an alarm sound from a speaker, not shown, when the control signal generation unit 41 is caused to execute the safe torque off. Similarly to the current frequency self-diagnosis unit 53, the current frequency mutual diagnosis unit 54 and the output frequency self-diagnosis unit 55 may cause the control signal generation unit 41 to output a control signal for reducing the supply of electric power to the motor 2 to the gate drive unit 13 instead of the control signal for executing the safe torque off.
Next, the safe speed monitoring and safe torque off operations of the control unit 12 will be described with reference to a flowchart. Fig. 5 is a flowchart showing an example of processing of the drive control unit of the control unit according to embodiment 1.
As shown in fig. 5, the drive control unit 40 determines whether or not the SLS signal is received from the safety device 4 (step S10). When the drive control unit 40 determines that the SLS signal has been received (Yes in step S10), it adjusts the current frequency ω to the current frequency ω c1 A calculation is performed (step S11). The drive control unit 40 controls the current frequency ω c1 Whether or not it is less than or equal to a prescribed speed limit value omega th The determination is made (step S12). The drive control unit 40 determines the current frequency ω c1 Less than or equal to a prescribed speed limit value omega th In the case of (step S12: yes), the current frequency ω is set to c1 With current frequency omega c2 Whether or not the difference is within a predetermined range R th1 The determination is performed (step S13).
The drive control unit 40 determines the current frequency ω c1 With current frequency omega c2 The difference is not in the predetermined range R th1 In the case of the other (No in step S13), the current frequency ω is set c1 And the output frequency omega out Whether or not the difference is within a predetermined range R th2 A determination is made (step S14). The drive control unit 40 determines the current frequency ω c1 Not less than or equal to a prescribed speed limit value omega th When it is determined that the current frequency omega is the current frequency (No in step S12) c1 With current frequency omega c2 The difference is within a predetermined range R th1 Otherwise (step S13: yes), or when it is determined that the current frequency ω is the current frequency ω c1 And the output frequency omega out The difference is in a predetermined range R th2 Otherwise (step S14: yes), execution of the safe torque off is determined, and the control unit 12 is caused to execute the safe torque off (step S15).
When the process of step S15 is completed, the drive control unit 40 determines that the SLS signal has not been received (step S10: no), or determines that the current frequency ω is the current frequency ω c1 And the output frequency omega out The difference is not in the predetermined range R th2 Otherwise (step S14: no), the process shown in FIG. 5 is ended. Note that the processing of the safety function unit 50 of the control unit 12 is the same as the processing of the drive control unit 40 shown in fig. 5, and is different from the processing of the drive control unit 40 shown in fig. 5The point is that the current frequency ω is used in steps S11, S12, S14 shown in fig. 5 c2 Instead of the current frequency omega c1 。
Fig. 6 is a diagram showing an example of the hardware configuration of the gate driving unit, the zero-crossing detection unit, the drive control unit, and the safety function unit according to embodiment 1. As shown in fig. 6, each of the gate driving unit 13, the zero-crossing detecting unit 15, the drive control unit 40, and the safety function unit 50 includes a computer having a processor 101, a memory 102, and an interface circuit 103. The processor 101, the memory 102, and the interface circuit 103 can transmit and receive data to and from each other via the bus 104.
A part of the PWM signal generation section 71 of the gate drive section 13 is realized by the interface circuit 103. The processor 101 in the gate drive unit 13 reads and executes the program stored in the memory 102 to thereby perform the functions of the PWM signal generation unit 71 and the output frequency calculation unit 72. The processor 101 in the zero-crossing detector 15 reads and executes a program stored in the memory 102 to thereby execute the functions of the current sign signal generators 61 and 62. The processor 101 in the drive control unit 40 reads and executes the programs stored in the memory 102, thereby executing the functions of the control signal generation unit 41, the current frequency calculation unit 42, and the monitoring unit 43. The processor 101 in the safety function unit 50 reads and executes the program stored in the memory 102 to thereby perform the functions of the current frequency calculation unit 51 and the monitoring unit 52. Further, the current sign signal I of the current frequency calculating sections 42 and 51 is sig1 、I sig2 The counting of the two rising and falling edges of (a) is performed by the pulse counting function of the processor 101. The current frequency calculation units 42 and 51 may be configured such that the processor 101 uses the input port of the interface circuit 103 to input the current sign signal I sig1 、I sig2 The number of inversions of (2) is counted.
The Processor 101 is an example of a Processing circuit, and includes 1 or more of a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and a system LSI (Large Scale Integration). The Memory 102 includes 1 or more of RAM (Random Access Memory), ROM (Read Only Memory), flash Memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (registered trademark). The memory 102 includes a recording medium on which a computer-readable program is recorded. The recording medium includes 1 or more of a nonvolatile or volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, and a DVD (Digital Versatile Disc). The control unit 12 may include an Integrated Circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).
In this way, the drive control unit 40 and the safety function unit 50 each include the processor 101 and a program operating on the processor 101, and the drive control unit 40 and the safety function unit 50 function independently of each other.
As described above, the power conversion device 1 according to embodiment 1 includes the main circuit portion 11, the control portion 12, the current sensor 14, and the half-wave rectifier 80. The main circuit unit 11 converts dc power into ac power, and supplies the converted ac power to the motor 2. The control unit 12 controls the main circuit unit 11. The current sensor 14 detects a current supplied from the main circuit unit 11 to the motor 2. Half-wave rectification unit 80 detects current detection signal I output from current sensor 14 det And performing half-wave rectification. The control unit 12 includes current frequency calculation units 42 and 51 and monitoring units 43 and 52. The current frequency calculating sections 42 and 51 detect the current I based on the half-wave rectified current signal I by the half-wave rectifying section 80 det I.e. the current detection signal I detr At least one of the rising timing and the falling timing of (c) to the current frequency ω c1 、ω c2 And (6) detecting. The monitoring units 43 and 52 calculate the current frequency ω based on the current frequency ω calculated by the current frequency calculation units 42 and 51 c1 、ω c2 While the speed of the motor 2 is monitored. Thus, the power conversion device 1 can monitor the safe speed without using an external detector such as an encoder, and the power conversion device 1 can detect the current detection signal I as a half-wave rectified waveform detr Since the processing is performed, it is possible to perform safe speed monitoring with a simple configuration without requiring a negative power supply.
In addition, electric powerThe conversion device 1 has a hysteresis comparator 83, and the hysteresis comparator 83 half-wave rectifies the current detection signal I half-wave rectified by the half-wave rectification section 80 by different threshold values detr The rising timing and the falling timing of (c) are compared. The current frequency calculation units 42 and 51 calculate the current frequency ω based on the rise timing obtained from the comparison result of the hysteresis comparator 83 c1 、ω c2 And (4) performing calculation. Thus, the power conversion device 1 does not detect, for example, a ripple of the drive current smaller than the difference between the sign inversion threshold Th1 and the sign inversion threshold Th2, and therefore can improve noise resistance. Therefore, for example, the current sign signal generating units 61 and 62 can have a simple configuration for the filter 82.
The monitoring units 43 and 52 monitor the current frequency ω calculated by the current frequency calculation units 42 and 51 c1 、ω c2 Or with the current frequency omega c1 、ω c2 The proportional value exceeding a prescribed speed limit value omega th In the case of (3), the supply of ac power from the main circuit unit 11 to the motor 2 can be stopped. Thus, the power conversion device 1 can stop the motor 2 when the speed of the motor 2 exceeds the predetermined speed limit value.
The monitoring units 43 and 52 monitor the current frequency ω calculated by the plurality of current frequency calculating units 42 and 51, respectively c1 、ω c2 The difference is within a predetermined range R th1 Otherwise, the power supply from the main circuit unit 11 to the motor 2 is stopped. Thus, the power converter 1 can perform mutual diagnosis between the redundant monitoring units 43 and 52, and can detect with high accuracy that the control unit 12 does not control the motor 2 in accordance with the safety signal.
The power conversion device 1 further includes a PWM signal generation unit 71 that generates a PWM signal for PWM-controlling the main circuit unit 11, and an output frequency ω that is the frequency of the ac voltage output from the main circuit unit 11 to the motor 2 out And an output frequency calculating unit 72 for performing the calculation. The monitoring units 43 and 52 monitor the current frequency ω calculated by the current frequency calculation units 42 and 51 c1 、ω c2 And the output calculated by the output frequency calculating section 72Frequency omega out The difference is within a predetermined range R th2 Otherwise, the power supply from the main circuit unit 11 to the motor 2 is stopped. Thus, the power converter 1 can detect with high accuracy that the control unit 12 does not control the motor 2 in accordance with the safety signal.
Embodiment 2.
The power conversion device according to embodiment 2 is different from the power conversion device 1 according to embodiment 1 in that the current frequency is calculated using a calculation model generated by machine learning. Hereinafter, components having the same functions as those in embodiment 1 will be given the same reference numerals, and description thereof will be omitted, focusing on differences from the drive control system 100 in embodiment 1.
Fig. 7 is a diagram showing a configuration example of a drive control system including the power conversion device according to embodiment 2. As shown in fig. 7, a drive control system 100A according to embodiment 2 includes a power conversion device 1A, a motor 2, an ac power supply 3, a safety device 4, and a measurement device 5. The measuring device 5 is an example of an external measuring device.
The power conversion device 1A is different from the power conversion device 1 in that a control unit 12A having a drive control unit 40A and a safety function unit 50A is provided instead of the control unit 12 having the drive control unit 40 and the safety function unit 50. The drive control unit 40A is different from the drive control unit 40 in that a current frequency calculation unit 42A is provided instead of the current frequency calculation unit 42. The current frequency calculation unit 42A uses a calculation model generated by machine learning, and calculates the current sign signal I from the current sign signal I sig1 To current frequency omega c1 And (6) performing calculation.
The safety function unit 50A is different from the safety function unit 50 in that a current frequency calculation unit 51A is provided instead of the current frequency calculation unit 51. The current frequency calculation unit 51A uses a calculation model generated by machine learning, and calculates the current sign signal I from the current sign signal I sig2 To current frequency omega c2 And (4) performing calculation. Since the current frequency calculation unit 42A and the current frequency calculation unit 51A have the same configuration, the following description will specifically discuss the current frequency calculation unitThe configuration of the current frequency calculation unit 42A will not be described in detail with respect to the configuration of the current frequency calculation unit 51A.
The measurement device 5 measures the ac current supplied from the power conversion device 1A to the motor 2 or the speed of the motor 2 at a predetermined cycle, and outputs a measurement value, which is data indicating the measurement result, to the power conversion device 1A. The measuring device 5 is a measuring device such as a data recorder having a current detection function. The measurement device 5 outputs current waveform data indicating a waveform of an ac current supplied from the power conversion device 1A to the motor 2 to the power conversion device 1A as a measurement value, for example. For example, when the DC/AC converter 21 is formed of a power semiconductor chip, the current waveform data is data obtained by adding a probe or the like of the direct measurement device 5 to the power semiconductor chip, and is data representing an actual current waveform that is not affected by noise due to measurement.
The measuring device 5 may be an encoder attached to the motor 2. In this case, the measuring device 5 detects the speed of the motor 2. The speed of the motor 2 is a mechanical angular speed of the motor 2, but may be an electrical angular speed of the motor 2. The measuring device 5 detects, for example, a rotational position of a rotating shaft of the motor 2, and detects a speed of the motor 2 based on a change in the detected rotational position. The measurement device 5 outputs speed data indicating the detected speed of the motor 2 to the power conversion device 1A as a measurement value.
Fig. 8 is a diagram showing a configuration example of a current frequency calculating unit according to embodiment 2. As shown in fig. 8, the current frequency calculation unit 42A includes a 1 st acquisition unit 63, a 2 nd acquisition unit 64, a learning unit 65, and a frequency calculation unit 66.
The 1 st acquisition unit 63 acquires the current sign signal I output from the zero-crossing detection unit 15 sig1 As state variables. The 2 nd acquisition unit 64 acquires the measurement value from the measurement device 5 at a predetermined cycle through wired communication or wireless communication via a network. For example, the 2 nd acquiring unit 64 acquires speed data or current waveform data as a measurement value from the measuring device 5.
The 2 nd acquisition unit 64 calculates the current frequency ω based on the acquired measurement value. The current frequency ω is the frequency of the alternating current supplied from the power conversion device 1A to the motor 2. When the acquired measurement value is current waveform data, the 2 nd acquisition unit 64 calculates the current frequency ω by performing fast fourier transform processing on the current waveform data. When the acquired measurement value is the speed data, the 2 nd acquiring unit 64 calculates the current frequency ω based on the speed data and the number of poles of the motor 2.
The learning unit 65 follows the current sign signal I obtained by the 1 st obtaining unit 63 sig1 And the current frequency ω calculated by the 2 nd acquisition unit 64, and a learning process is performed to generate the calculation model M. The calculation model generated by the learning unit 65 is a current sign signal I sig1 As input, the current frequency ω c1 And outputting the calculation model.
The learning unit 65 performs a learning process by so-called supervised learning, for example, according to a neural network model, and generates a calculation model M composed of a neural network. Here, the supervised learning refers to a method of generating a calculation model for estimating a result from an input by machine learning in which a large number of data sets of a certain input and a result are given to a learning device, and features existing in these data sets are learned.
The neural network is composed of an input layer composed of a plurality of neurons, an intermediate layer composed of a plurality of neurons, and an output layer composed of a plurality of neurons. The intermediate layer may be 1 layer or 3 or more layers. In addition, the intermediate layer is also referred to as a hidden layer.
Fig. 9 is a diagram showing an example of the 3-layer neural network according to embodiment 2. When the learning unit 65 uses the 3-layer neural network shown in fig. 9, if a plurality of inputs are input to the input layers X1, X2, and X3, the input values are multiplied by the weight W1 and input to the intermediate layers Y1 and Y2. Then, the values input to the intermediate layers Y1, Y2 are multiplied by the weight W2 and output from the output layers Z1, Z2, Z3. The output result varies depending on the values of the weights W1 and W2.
The weight W1 is the weights W11 to W16, and the weight W2 is the weights W21 to W26. The value input to the input layer X1 is multiplied by the weight w11 and input to the intermediate layer Y1, and multiplied by the weight w12 and input to the intermediate layer Y2. The value input to the input layer X2 is multiplied by the weight w13 and input to the intermediate layer Y1, and multiplied by the weight w14 and input to the intermediate layer Y2. The value input to the input layer X3 is multiplied by the weight w15 and input to the intermediate layer Y1, and multiplied by the weight w16 and input to the intermediate layer Y2. The value input to the intermediate layer Y1 is multiplied by the weight w21 and input to the output layer Z1, multiplied by the weight w23 and input to the output layer Z2, and multiplied by the weight w25 and input to the output layer Z3. The value input to the intermediate layer Y2 is multiplied by the weight w22 and input to the output layer Z1, multiplied by the weight w24 and input to the output layer Z2, and multiplied by the weight w26 and input to the output layer Z3.
The neural network used by the calculation model M is based on a signal I containing a current sign sig1 The data set combined with the current frequency ω learns the frequency detection method by so-called supervised learning. That is, the neural network used for calculating the model M inputs the current sign signal I to the input layer by adjusting the weights W1 and W2 sig1 The result output from the output layer is close to the current frequency ω obtained from the measured value, and learning processing is performed to generate the calculation model M.
The learning unit 65 can also generate the calculation model M by so-called unsupervised learning. The unsupervised learning is a method of generating a calculation model by machine learning in which a machine learning device learns the distribution of input data by giving only a large amount of input data to the machine learning device, and the input data is compressed, classified, shaped, and the like without giving supervisory data corresponding to the input data. In unsupervised learning, data with similar characteristics can be clustered in a data group. In the unsupervised learning, the result of clustering can be used to predict an output by setting a certain criterion and performing an output assignment such as optimization. The intermediate problem setting between the unsupervised learning and the supervised learning is sometimes referred to as semi-supervised learning. In semi-supervised learning, input and output data sets are used for only a part of learning, and other learning uses only input data.
As the Learning algorithm used for the calculation model M, deep Learning (Deep Learning) for Learning the extraction of the feature quantity itself may be used instead of the neural network, and machine Learning may be performed by other known methods such as genetic programming, functional logic programming, and support vector machine.
Returning to fig. 8, the description of the current frequency calculation unit 42A is continued. The learning unit 65 sets the generated calculation model M in the frequency calculation unit 66. The frequency calculating part 66 calculates the current sign signal I sig1 Input into the calculation model M, so that the calculation model M can be used for current frequency omega c1 And (6) performing calculation.
The hardware configuration of the current frequency calculating unit 42A is the same as that shown in fig. 6. The 1 st acquiring unit 63, the 2 nd acquiring unit 64, and the frequency calculating unit 66 are each implemented in part by an interface circuit 103. The functions of the 1 st acquisition unit 63, the 2 nd acquisition unit 64, the learning unit 65, and the frequency calculation unit 66 are executed by the processor 101 reading and executing a program stored in the memory 102. The 1 st acquiring unit 63, the 2 nd acquiring unit 64, the learning unit 65, and the frequency calculating unit 66 may be partly or entirely configured by hardware such as ASIC or FPGA.
In the above example, the calculation model is calculated inside the power conversion device 1A, but the calculation model M may be generated in a device learning device different from the power conversion device 1A. Fig. 10 is a diagram showing another example of the configuration of a drive control system including the power conversion device according to embodiment 2. In the example shown in fig. 10, the drive control system 100A according to embodiment 2 includes a power conversion device 1A, a motor 2, an ac power supply 3, a safety device 4, a measurement device 5, and a machine learning device 6.
The current frequency calculation unit 42A of the power conversion device 1A shown in fig. 10 is different from the current frequency calculation unit 42A shown in fig. 7 in that the 1 st acquisition unit 63, the 2 nd acquisition unit 64, and the learning unit 65 shown in fig. 8 are not included. The current frequency calculation unit 51A shown in fig. 10 has the same configuration as the current frequency calculation unit 42A shown in fig. 10.
Fig. 11 is a diagram showing a configuration example of the machine learning device according to embodiment 2. As shown in fig. 11, the machine learning device 6 includes a 1 st acquisition unit 111, a 2 nd acquisition unit 112, a learning unit 113, a storage unit 114, and an output unit 115. The machine learning device 6 is communicably connected to the power conversion device 1A via a network, not shown, for example. The machine learning device 6 may be disposed on a cloud server.
The 1 st acquisition unit 111 acquires the current sign signal I from the power conversion device 1A at a predetermined cycle through a network by wired communication or wireless communication sig1 、I sig2 As state variables. The 2 nd acquisition unit 112 acquires the measurement value from the measurement device 5 at a predetermined cycle through the network by wireless communication. For example, the measurement value acquired by the 2 nd acquisition unit 112 is the same as the measurement value acquired by the 2 nd acquisition unit 64. The 2 nd acquisition unit 112 calculates the current frequency ω based on the acquired measurement value, as in the 2 nd acquisition unit 64.
The learning unit 113 follows the current sign signal I obtained by the 1 st obtaining unit 111 sig1 And the current frequency ω calculated by the 2 nd acquisition unit 112, the same learning process as that of the learning unit 65 is performed to generate the calculation model M. The learning unit 113 also follows the current sign signal I obtained by the 1 st obtaining unit 111 sig2 And the current frequency ω calculated by the 2 nd acquisition unit 112, the same learning process as that of the learning unit 65 is performed to generate the calculation model M.
The learning unit 113 stores the generated calculation model M in the storage unit 114. The output unit 115 transmits the information of the calculation model M stored in the storage unit 114 to the power conversion device 1A via a network by wired communication or wireless communication. The control unit 12A of the power conversion device 1A sets the information of the calculation model M transmitted from the machine learning device 6 in the current frequency calculation unit 42A and the current frequency calculation unit 51A. For example, the control section 12A will use the current sign signal I sig1 The generated calculation model M is set in the current frequency calculation unit 42A, and the current sign signal I is used sig2 And the generated calculation model M is setThe current frequency calculating section 51A.
The hardware configuration of the machine learning device 6 is the same as that shown in fig. 6. The 1 st acquiring unit 111, the 2 nd acquiring unit 112, and the output unit 115 are each implemented in part by the interface circuit 103. The storage section 114 is implemented by the memory 102. The functions of the 1 st acquisition unit 111, the 2 nd acquisition unit 112, the learning unit 113, and the output unit 115 are executed by the processor 101 reading and executing a program stored in the memory 102. The 1 st acquisition unit 111, the 2 nd acquisition unit 112, the learning unit 113, and the output unit 115 may be partly or entirely configured by hardware such as an ASIC or FPGA.
The learning unit 113 may also generate the calculation model M in accordance with a data set created for the plurality of power conversion devices 1A. Further, the device learning apparatus 6 can acquire the current sign signal I from the plurality of power conversion apparatuses 1A used in the same site sig1 、I sig2 It is also possible to obtain the current symbol signal I from a plurality of power conversion devices 1A that operate independently at different sites sig1 、I sig2 . The device learning apparatus 6 may be added as the current sign signal I in the middle sig1 、I sig2 Or removing the power conversion device 1A as the acquisition target from the acquisition target. Further, it is also possible to install the device learning device 6, which generates the calculation model M by device learning for a certain power conversion device 1A, in another power conversion device 1A, and update the calculation model M by relearning for the another power conversion device 1A.
The hardware configuration of the drive control unit 40A and the safety function unit 50A is the same as that of the drive control unit 40 and the safety function unit 50. The functions of the drive control unit 40A and the safety function unit 50A are executed by the processor 101 reading and executing a program stored in the memory 102. The drive control unit 40A and the safety function unit 50A may be partly or entirely configured by hardware such as an ASIC or FPGA.
As described above, the current frequency calculation units 42A and 51A of the power conversion device 1A according to embodiment 2 can use the through-devicesCalculation model generated by learning versus current frequency ω c1 、ω c2 And (6) performing calculation. Thereby, the current frequency ω can be accurately measured c1 、ω c2 And (6) performing calculation.
The current frequency calculation units 42A and 51A have a calculation model M based on the current sign signal I sig1 、I sig2 And a current frequency ω obtained from a measured value indicating a waveform of the current or a speed of the motor 2 measured by the measuring device 5, and generated by machine learning. Sign signal of current I sig1 、I sig2 Each is an example of a signal indicating at least one of the rising timing and the falling timing. The current frequency calculation units 42A and 51A input the current sign signal I to the calculation model M sig1 、I sig2 So that the calculation model M is used to calculate the current frequency omega c1 、ω c2 And (6) performing calculation. The current sensor 14 is susceptible to noise when the motor 2 operates at a low speed or when the current supplied to the motor 2 is low. The current frequency calculation units 42A and 51A make the calculation model M to the current frequency ω c1 、ω c2 By performing the calculation, even when the current sensor 14 is affected by noise, the current frequency ω can be accurately measured c1 、ω c2 And (4) performing calculation.
The current frequency calculation units 42A and 51A include a 1 st acquisition unit 63, a 2 nd acquisition unit 64, and a learning unit 65. The 1 st acquisition part 63 acquires the current sign signal I sig1 、I sig2 As state variables. The 2 nd acquisition unit 64 acquires a measurement value from the measurement device 5, and calculates the current frequency ω based on the acquired measurement value. The learning unit 65 generates the calculation model M by machine learning based on a data set created by using a combination of the state variable acquired by the 1 st acquisition unit 63 and the current frequency ω calculated by the 2 nd acquisition unit 64. Thus, the power conversion device 1A can generate the calculation model M, and therefore, even when there is an individual difference between the power conversion devices 1A, it is possible to accurately measure the current frequency ω c1 、ω c2 And (4) performing calculation.
In addition, the fruitThe drive control system 100A according to embodiment 2 includes a machine learning device 6 that generates a calculation model M. The machine learning device 6 includes a 1 st acquisition unit 111, a 2 nd acquisition unit 112, and a learning unit 113. The 1 st acquisition unit 111 acquires a current sign signal I sig1 、I sig2 As state variables. The 2 nd acquisition unit 112 acquires a measurement value from the measurement device 5, and calculates the current frequency ω based on the acquired measurement value. The learning unit 113 generates the calculation model M by machine learning based on a data set created by using a combination of the state variable acquired by the 1 st acquisition unit 111 and the current frequency ω calculated by the 2 nd acquisition unit 112. Thus, for example, the machine learning device 6 can generate the common calculation model M for the plurality of power conversion devices 1A, and thus can easily generate the calculation model M as compared with a case where the calculation model M is generated for each power conversion device 1A.
The configuration shown in the above embodiment is an example of the contents of the present invention, and may be combined with other known techniques, and a part of the configuration may be omitted or modified without departing from the scope of the present invention.
Description of the reference symbols
1. 1A power conversion device, 2 motor, 3 AC power supply, 4 safety device, 5 measuring device, 6 machine learning device, 11 main circuit part, 12A control part, 13 grid drive part, 14 current sensor, 15 zero crossing detection part, 16 display, 20AC/DC converter, 21DC/AC converter, 22 3 phase diode bridge, 23 smoothing capacitor, 31, 32, 33, 34, 35, 36 switch element, 40A drive control part, 41 control signal generation part, 42A, 51A current frequency calculation part, 43, 52 monitoring part, 44, 53 current frequency self-diagnosis part, 45, 54 current frequency mutual diagnosis part, 46, 55 output frequency self-diagnosis part, 50A safety function part, 61, 62 current sign signal generating part, 63, 111 1 st obtaining part, 64, 112 2 nd obtaining part, 65, 113 learning part, 66 frequency calculating part, 71PWM signal generating part, 72 output frequency calculating part, 80 half-wave rectifying part, 81 operational amplifier, 82 filter, 83 hysteresis comparator, 91 comparator, 92, 93, 94, 95, 96 resistance, 100A drive control system, 114 storage memorySection, 115 output section, I det 、I detr Current detection signal, I sig1 、I sig2 Sign signal of current, R th1 、R th2 Predetermined range, th1, th2 sign reversal threshold, ω c1 、ω c2 Frequency of current, omega out Output frequency, omega th A speed limit is specified.

Claims (12)

1. A power conversion device is characterized by comprising:
a main circuit unit that converts dc power into ac power and supplies the converted ac power to a motor;
a control unit that controls the main circuit unit;
a current sensor that detects a current supplied from the main circuit unit to the motor; and
a half-wave rectification section that half-wave rectifies a current detection signal output from the current sensor,
the control unit includes:
a current frequency calculation unit that calculates a current frequency, which is a frequency of the current, based on at least one of a rising timing and a falling timing of the current detection signal half-wave rectified by the half-wave rectification unit; and
and a monitoring unit that monitors the speed of the motor based on the current frequency calculated by the current frequency calculating unit.
2. The power conversion apparatus according to claim 1,
has a hysteresis comparator which compares rising timing and falling timing of a current detection signal half-wave rectified by the half-wave rectification section by different thresholds,
the current frequency calculation unit calculates the current frequency based on the rising timing and the falling timing obtained from the comparison result of the hysteresis comparator.
3. The power conversion apparatus according to claim 1 or 2,
the monitoring unit stops the supply of electric power from the main circuit unit to the motor when the current frequency calculated by the current frequency calculation unit or a value proportional to the current frequency and not the current frequency itself exceeds a predetermined speed limit value.
4. The power conversion apparatus according to claim 3,
a plurality of the current frequency calculating sections are provided,
the monitoring unit stops the supply of electric power from the main circuit unit to the motor when the difference between the current frequencies calculated by the plurality of current frequency calculating units is outside a predetermined range.
5. The power conversion apparatus according to claim 3, characterized by comprising:
a PWM signal generation unit that generates a PWM signal for PWM-controlling the main circuit unit; and
an output frequency calculating unit that calculates an output frequency that is a frequency of an alternating-current voltage output from the main circuit unit to the motor,
the monitoring unit stops the supply of electric power from the main circuit unit to the motor when a difference between the current frequency calculated by the current frequency calculating unit and the output frequency calculated by the output frequency calculating unit is outside a predetermined range.
6. The power conversion apparatus according to claim 4, characterized by comprising:
a PWM signal generation unit that generates a PWM signal for PWM-controlling the main circuit unit; and
an output frequency calculating unit that calculates an output frequency that is a frequency of an alternating-current voltage output from the main circuit unit to the motor,
the monitoring unit stops the supply of electric power from the main circuit unit to the motor when a difference between the current frequency calculated by the current frequency calculating unit and the output frequency calculated by the output frequency calculating unit is outside a predetermined range.
7. The power conversion apparatus according to claim 1 or 2,
the current frequency calculation unit calculates the current frequency using a calculation model generated by machine learning.
8. The power conversion apparatus according to claim 7,
the calculation model is generated by machine learning based on a signal indicating at least one of the rising timing and the falling timing and a frequency of the current obtained from a measured value indicating a waveform of the current or a speed of the motor measured by an external measuring device,
the current frequency calculation unit causes the calculation model to calculate the current frequency by inputting a signal indicating at least one of the rising timing and the falling timing to the calculation model.
9. The power conversion apparatus according to claim 8, characterized by comprising:
a 1 st acquisition unit that acquires, as a state variable, a signal indicating at least one of the rising timing and the falling timing;
a 2 nd acquisition unit that acquires the measurement value from the external measurement device and calculates a frequency of the current based on the acquired measurement value; and
a learning unit that generates the calculation model by machine learning based on a data set created by a combination of the state variable acquired by the 1 st acquisition unit and the frequency of the current calculated by the 2 nd acquisition unit.
10. A drive control system characterized by comprising:
the power conversion device of claim 8; and
a machine learning device that generates the computational model,
the machine learning device has:
a 1 st acquisition unit that acquires, as a state variable, a signal indicating at least one of the rising timing and the falling timing;
a 2 nd acquisition unit that acquires the measurement value from the external measurement device and calculates a frequency of the current based on the acquired measurement value; and
a learning unit that generates the calculation model by machine learning based on a data set created by a combination of the state variable acquired by the 1 st acquisition unit and the frequency of the current calculated by the 2 nd acquisition unit.
11. A machine learning apparatus is characterized by comprising:
a 1 st acquisition unit that acquires, as a state variable, a signal indicating at least one of a rising timing and a falling timing of a current detection signal, which is a half-wave rectified current detection signal output from a current sensor that detects a current supplied to a motor;
a 2 nd acquisition unit that acquires a measurement value indicating a waveform of the current or a speed of the motor measured by an external measurement device, and calculates a frequency of the current based on the acquired measurement value; and
and a learning unit that generates a calculation model for calculating the frequency of the current by machine learning based on a data set created by a combination of the state variable acquired by the 1 st acquisition unit and the frequency of the current calculated by the 2 nd acquisition unit.
12. A motor monitoring method, comprising the steps of:
detecting, by a current sensor, a current supplied from a main circuit unit that converts direct-current power into alternating-current power and supplies the converted alternating-current power to a motor;
calculating a current frequency, which is a frequency of the current, based on at least one of a rising timing and a falling timing of a current detection signal that is output from the current sensor and half-wave rectified by a half-wave rectification section; and
monitoring the speed of the motor based on the calculated current frequency.
CN201980093995.1A 2019-03-18 2019-11-21 Power conversion device, drive control system, machine learning device, and motor monitoring method Active CN113574791B (en)

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