CN111817630B

CN111817630B - Rotating speed control method and device, motor speed regulation system, storage medium and processor

Info

Publication number: CN111817630B
Application number: CN202010573291.9A
Authority: CN
Inventors: 韩一博; 宋昕昱; 罗鸿智
Original assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Current assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2021-11-16
Anticipated expiration: 2040-06-22
Also published as: CN111817630A

Abstract

The invention discloses a rotating speed control method, a rotating speed control device, a motor speed regulating system, a storage medium and a processor, wherein the method comprises the following steps: acquiring a given rotating speed of a motor in a rotating speed loop in a double closed loop motor vector control system consisting of the rotating speed loop and a current loop; and determining the real-time torque of the motor, and dynamically adjusting the amplitude limit range of the output variable of a rotating speed PI regulator in a rotating speed loop according to the real-time torque of the motor and the given rotating speed of the motor so as to dynamically inhibit the rotating speed saturation phenomenon generated in the speed increasing process of the motor. According to the scheme, the problem that the rotating speed of the motor cannot be accurately controlled due to the fact that the output variable limiting range of the rotating speed PI regulator cannot be adjusted according to the rotating speed change can be solved, and the effect that the rotating speed of the motor can be accurately controlled due to the fact that the output variable limiting range of the rotating speed PI regulator can be adjusted according to the rotating speed change is achieved.

Description

Rotating speed control method and device, motor speed regulation system, storage medium and processor

Technical Field

The invention belongs to the technical field of motors, and particularly relates to a rotating speed control method and device, a motor speed regulating system, a storage medium and a processor, in particular to a rotating speed saturation dynamic suppression method and device of a permanent magnet synchronous motor speed regulating system, the storage medium and the processor.

Background

The permanent magnet synchronous motor is a motor with simple structure, low cost and high efficiency, and is widely applied to the industrial engineering fields such as aerospace, numerical control machine tools, electric vehicles and the like.

In some schemes, most of speed regulating systems for controlling the permanent magnet synchronous motor are vector control systems, the vector control system is a double closed loop feedback control system, a rotating speed loop (namely a speed control loop) is used as an outer loop, a current loop (namely a current control loop) is used as an inner loop, and each control loop is provided with a PI regulator for regulating an error between a given value and an actual value of a control variable, so that the motor is driven to operate.

In the starting process and the flux weakening and speed increasing process of the motor, a static error can be generated in a control system, and the PI regulator needs to eliminate the static error in the control system. The accumulation of errors can cause the integral saturation phenomenon of a rotating speed loop and a current loop, and in order to inhibit the integral saturation phenomenon, the output variable of the PI regulator needs to be limited, but the output variable limiting range of the rotating speed PI regulator cannot be adjusted according to the change of the rotating speed, so that the rotating speed of the motor cannot be accurately controlled.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The present invention aims to solve the above-mentioned drawbacks by providing a method and an apparatus for controlling a rotational speed, a motor speed control system, a storage medium, and a processor, so as to solve the problem that the rotational speed of a motor cannot be accurately controlled because the output variable limit range of a rotational speed PI regulator cannot be adjusted according to the change of the rotational speed, and achieve the effect that the output variable limit range of the rotational speed PI regulator can be adjusted according to the change of the rotational speed, so that the rotational speed of the motor can be accurately controlled.

The invention provides a rotating speed control method, which comprises the following steps: acquiring a given rotating speed of a motor in a rotating speed loop in a double closed loop motor vector control system consisting of the rotating speed loop and a current loop; and determining the real-time torque of the motor, and dynamically adjusting the amplitude limit range of the output variable of a rotating speed PI regulator in a rotating speed loop according to the real-time torque of the motor and the given rotating speed of the motor so as to dynamically inhibit the rotating speed saturation phenomenon generated in the speed increasing process of the motor.

Optionally, determining a real-time torque of the motor, and dynamically adjusting an amplitude limit range of an output variable of a rotating speed PI regulator in a rotating speed loop according to the real-time torque of the motor and a given rotating speed of the motor, including: determining real-time torque of a motor, and determining given power of the motor at a given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor; determining a given q-axis current reference value of the motor according to the given power; and determining the upper limit and the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference.

Optionally, determining a real-time torque of the motor, and determining a given power of the motor at a given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor, includes: detecting output torque of a motor during operation as real-time torque of the motor; and taking the product of the real-time torque of the motor and the given rotating speed of the motor as the given power of the motor at the given rotating speed of the motor.

Optionally, determining a given q-axis current reference value of the motor according to the given power comprises: detecting the maximum value of the voltage of a direct-current side bus of a motor speed regulating system to obtain the maximum value of the voltage of the direct-current bus; performing reciprocal and proportional calculation processing on the maximum value of the direct-current bus voltage to obtain the reciprocal of the maximum value of the direct-current side bus voltage with a proportional coefficient; and determining the product of the given power and the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient as a q-axis current reference value of the motor at the given rotating speed of the motor.

Optionally, determining an upper limit of an amplitude limit range and a lower limit of the amplitude limit range of an output variable of the rotation speed PI regulator based on the given q-axis current reference value includes: multiplying the given q-axis current reference value by a set proportionality coefficient to obtain a product of the given q-axis current reference value and the set proportionality coefficient; converting the direction of the product of the given q-axis current reference value and a set proportionality coefficient to obtain the product of the given q-axis current reference value and the set proportionality coefficient in the reverse direction; taking the product of the given q-axis current reference value and a set proportionality coefficient as the upper limit of the amplitude limit range of the output variable of the rotating speed PI regulator; and taking the product of the inverted given q-axis current reference value and a set proportionality coefficient as the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator.

Optionally, the method further comprises: and under the condition of dynamically inhibiting the rotating speed saturation phenomenon generated in the motor speed increasing process, the current PI regulator in the current loop is dynamically inhibited from outputting a given q-axis voltage amplitude.

In accordance with another aspect of the present invention, there is provided a rotation speed control apparatus, including: an acquisition unit and a rotational speed saturation suppression unit; the acquisition unit is used for acquiring the given rotating speed of the motor in a rotating speed loop in a double closed-loop motor vector control system consisting of the rotating speed loop and a current loop; the rotating speed saturation suppression unit is used for determining the real-time torque of the motor, and dynamically adjusting the amplitude limit range of the output variable of the rotating speed PI regulator in the rotating speed loop according to the real-time torque of the motor and the given rotating speed of the motor so as to dynamically suppress the rotating speed saturation phenomenon generated in the speed increasing process of the motor.

Optionally, the rotation speed saturation suppression unit includes: the device comprises a power determining module, a current determining module and an amplitude limiting module; the rotating speed saturation suppression unit determines the real-time torque of the motor, dynamically adjusts the amplitude limit range of the output variable of the rotating speed PI adjuster in the rotating speed ring according to the real-time torque of the motor and the given rotating speed of the motor, and comprises the following steps: the power determination module is used for determining the real-time torque of the motor and determining the given power of the motor at the given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor; the current determination module is used for determining a given q-axis current reference value of the motor according to the given power; and the amplitude limiting module is used for determining the upper limit of the amplitude limiting range and the lower limit of the amplitude limiting range of the output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference.

Optionally, the power determining module includes: the motor torque detection module and the first multiplier; the power determination module determines real-time torque of a motor, and determines given power of the motor at a given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor, and comprises the following steps: the motor torque detection module is used for detecting the output torque of the motor during operation as the real-time torque of the motor; and the first multiplier is used for taking the product of the real-time torque of the motor and the given rotating speed of the motor as the given power of the motor at the given rotating speed of the motor.

Optionally, the current determination module comprises: the direct current bus voltage detection module, the voltage processing module and the second multiplier are connected; the current determination module determines a given q-axis current reference value of the motor based on the given power, including: the direct current bus voltage detection module is used for detecting the maximum value of the direct current side bus voltage of the motor speed regulating system to obtain the maximum value of the direct current bus voltage; the voltage processing module is used for carrying out reciprocal taking and proportion calculation processing on the maximum value of the direct-current bus voltage to obtain the reciprocal of the maximum value of the direct-current side bus voltage with a proportion coefficient; and the second multiplier is used for determining the product of the given power and the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient as a q-axis current reference value of the motor at the given rotating speed of the motor.

Optionally, the amplitude limiting module comprises: the device comprises a proportion calculation module, a reverse control module, a maximum amplitude limiting module and a minimum amplitude limiting module; the amplitude limiting module determines an upper limit of an amplitude limiting range and a lower limit of the amplitude limiting range of an output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference, and comprises the following steps: the proportion calculation module is used for multiplying the given q-axis current reference value by a set proportion coefficient to obtain the product of the given q-axis current reference value and the set proportion coefficient; the reverse control module is used for converting the direction of the product of the given q-axis current reference value and the set proportionality coefficient to obtain the reverse product of the given q-axis current reference value and the set proportionality coefficient; the maximum amplitude limiting module is used for taking the product of the given q-axis current reference value and a set proportionality coefficient as the upper limit of the amplitude limiting range of the output variable of the rotating speed PI regulator; and the minimum amplitude limiting module is used for taking the product of the inverted given q-axis current reference value and a set proportionality coefficient as the lower limit of the amplitude limiting range of the output variable of the rotating speed PI regulator.

Optionally, the rotation speed saturation suppression unit is further configured to dynamically suppress a given q-axis voltage amplitude output by the current PI regulator in the current loop in the case of dynamically suppressing a rotation speed saturation phenomenon generated during the motor speed increasing process.

In another aspect, the present invention provides a motor speed control system, including: the rotational speed control device described above.

In accordance with the above method, a further aspect of the present invention provides a storage medium, which includes a stored program, wherein when the program runs, a device in which the storage medium is located is controlled to execute the above method for controlling the rotational speed.

In accordance with the above method, a further aspect of the present invention provides a processor for running a program, wherein the program is run to execute the above method for controlling the rotational speed.

According to the scheme, a rotating speed saturation dynamic suppression module is arranged at the output end of a rotating speed PI regulator in a motor vector control system, and the output variable of the rotating speed PI regulator in a double closed loop type vector control system, namely the current i of a given motor q axis_qLimiting the upper limit and the lower limit of the amplitude to prevent the upper limit and the lower limit of the amplitude from being excessively large in the positive direction or excessively small in the negative direction to cause i_qAnd entering a saturation interval to control the output variable of the rotating speed PI regulator in a reasonable variation range, inhibit the integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system, and be beneficial to improving the running stability of the motor.

Furthermore, according to the scheme of the invention, the output variable i of the rotating speed PI regulator is calculated and processed by the motor power under different given rotating speed conditions_qThe upper limit and the lower limit of the amplitude are changed according to the change of the motor power under different given rotating speed conditions, so that the suppression range of a given q-axis current saturation interval is dynamically changed along with the power when the power of the motor is changed, the integral saturation phenomenon of the rotating speed is dynamically suppressed by the variable frequency motor vector control system under different given rotating speed conditions, and the control performance of the motor speed regulating system is favorably improved.

Furthermore, the scheme of the invention outputs the variable i to the rotating speed ring_qAmplitude limiting is carried out to prevent the rotation speed from entering a saturation interval, and a variable i is output by a rotation speed ring_qThe upper limit and the lower limit of the variation amplitude are calculated by the maximum value of the motor power and the bus voltage on the direct current sideThe processing results can ensure that the subsequent d-q axis output voltage is not higher than the maximum value of the direct-current side bus voltage to generate a voltage saturation phenomenon, and the problem of the d-q axis voltage saturation phenomenon of the motor caused by errors generated by the rotating speed integral saturation phenomenon in a vector control system of the permanent magnet synchronous motor can be solved; therefore, a voltage amplitude limiting module which is configured at the output end of the current loop PI regulator and used for controlling the given d-q axis voltage value output by the PI regulator not to enter a saturation region can be eliminated, and the control process is simplified.

Therefore, the scheme of the invention gives the q-axis current i of the motor by the output variable of a rotating speed loop PI regulator in the double closed loop type vector control system_qLimiting the upper limit and the lower limit of the amplitude to prevent the upper limit and the lower limit of the amplitude from being excessively large in the positive direction or excessively small in the negative direction to cause i_qEntering a saturation interval to control the output variable of the rotating speed PI regulator within a reasonable variation range, and dynamically inhibiting the rotating speed saturation phenomenon generated in the motor speed increasing process, so that the problem that the rotating speed saturation phenomenon caused by the error integral of the rotating speed PI regulator in a motor vector control system influences the operation stability of the motor can be solved, and the effect of improving the operation stability of the motor is achieved; the problem that the rotating speed of the motor cannot be accurately controlled due to the fact that the output variable limiting range of the rotating speed PI regulator cannot be adjusted according to the rotating speed change can be solved, and the effect that the rotating speed of the motor can be accurately controlled due to the fact that the output variable limiting range of the rotating speed PI regulator can be adjusted according to the rotating speed change is achieved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic structural diagram of a rotational speed control apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an embodiment of a permanent magnet synchronous motor speed regulating system to which the motor speed saturation dynamic suppression method of the present invention is applied;

FIG. 3 is a schematic structural diagram of a rotational speed saturation dynamic suppression module according to an embodiment of the present invention;

FIG. 4 is a schematic control flow diagram of a rotational speed saturation dynamic suppression module according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating the effect of the rotational speed control of the rotational speed saturation dynamic suppression module of the present invention at 1800 rpm;

FIG. 6 is a diagram illustrating the effect of the rotational speed control of the rotational speed saturation dynamic suppression module of the present invention under 2400 rpm (revolutions per minute);

FIG. 7 is a diagram illustrating the effect of the rotational speed control of the rotational speed saturation dynamic suppression module of the present invention under 3000 rpm;

FIG. 8 is a flowchart illustrating a rotational speed control method according to an embodiment of the present invention;

FIG. 9 is a schematic flow chart diagram illustrating one embodiment of a range limitation for dynamically adjusting the output variable of the PI regulator in the speed loop according to the method of the present invention;

FIG. 10 is a schematic flow chart illustrating one embodiment of the method of the present invention for determining a given power of a motor at a given speed of the motor;

FIG. 11 is a schematic flow chart diagram illustrating one embodiment of determining a given q-axis current reference for the motor in the method of the present invention;

fig. 12 is a schematic flow chart of an embodiment of determining the upper limit of the amplitude limit range and the lower limit of the amplitude limit range of the output variable of the rotational speed PI regulator in the method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to an embodiment of the present invention, there is provided a rotational speed control apparatus. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The rotating speed control device can be applied to a motor speed regulation system, particularly a permanent magnet synchronous motor speed regulation system, and specifically can be arranged in a rotating speed ring in a double closed-loop motor vector control system formed by the rotating speed ring and a current ring and positioned at the output end of a rotating speed PI regulator in the double closed-loop motor vector control system, for example, a rotating speed saturation dynamic suppression module applying the motor rotating speed saturation dynamic suppression method is added at the output end of the rotating speed PI regulator. In the rotating speed ring, a rotating speed ring closed-loop error tracking feedback unit is matched with the rotating speed PI regulator. The permanent magnet synchronous motor rotation speed control device may include: the device comprises an acquisition unit and a rotating speed saturation suppression unit.

In an alternative example, the obtaining unit may be configured to obtain the given rotation speed of the motor in a rotation speed loop in a double closed loop motor vector control system formed by the rotation speed loop and a current loop.

In an optional example, the rotation speed saturation suppression unit may be configured to determine a real-time torque of the motor, and dynamically adjust a range of a limit of an output variable of a rotation speed PI regulator in a rotation speed loop according to the real-time torque of the motor and a given rotation speed of the motor, so as to control the output variable of the rotation speed PI regulator within a safe variation range of a double closed-loop motor vector control system, and dynamically suppress a rotation speed saturation phenomenon generated during a motor speed-up process. By making the output variable i of a speed PI regulator_qThe upper limit and the lower limit of the amplitude are changed according to the change of the motor power under different given rotating speed conditions, so that the suppression range of a given q-axis current saturation interval is dynamically changed along with the power when the power of the motor is changed, and the amplitude limit range of an output end amplitude limit module of a rotating speed PI regulator in a permanent magnet synchronous motor vector control system can be adjusted according to the change of the rotating speed.

For example: controlling the output variable of the rotating speed PI regulator within a reasonable variation range, and preventing the rotating speed saturation phenomenon caused by error integration of the PI regulator; meanwhile, when the rotating speed of the motor is changed, the control system can adjust the amplitude limit range of the output variable of the PI regulator according to the current rotating speed of the motor without changing the system structure and system parameters, so that the dynamic amplitude control of the output variable of the PI regulator is realized, and the control performance of the motor speed regulating system is improved.

Therefore, the amplitude limiting range of the saturation suppression module at the output end of the rotating speed PI regulator is adjusted according to the change of the rotating speed of the motor, the output variable of the rotating speed PI regulator is controlled within a reasonable change range, the variable frequency motor vector control system dynamically suppresses the integral saturation phenomenon of the rotating speed under different given rotating speed conditions, the problem of integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system can be solved, and the stability of the vector control system is improved.

Alternatively, the rotation speed saturation suppression unit, i.e., the rotation speed saturation dynamic suppression module, may include: a power determination module (e.g., a motor torque-to-power conversion module), a current determination module (e.g., an equivalent current calculation module), and an amplitude limitation module (e.g., a dynamic amplitude limitation module).

Accordingly, the determining a real-time torque of the motor by the rotation speed saturation suppression unit, and dynamically adjusting the amplitude limit range of the output variable of the rotation speed PI regulator in the rotation speed loop according to the real-time torque of the motor and the given rotation speed of the motor may include:

the power determination module (such as a motor torque-power conversion module) can be used for determining the real-time torque of the motor and determining the given power of the motor at the given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor. For example: and the motor torque-power conversion module can detect the output torque when the motor runs. The output torque of the motor and the given rotating speed are input into the multiplier, and the given power of the motor under the given rotating speed condition can be obtained.

More optionally, the power determination module (e.g., a motor torque-to-power conversion module) may include: the motor torque detection module and the first multiplier. For example: the motor torque-power conversion module can be composed of a motor torque detection module and a multiplier.

Accordingly, the determining a real-time torque of the motor by the power determining module (such as a motor torque-power converting module) and determining a given power of the motor at a given rotation speed of the motor according to the real-time torque of the motor and the given rotation speed of the motor may include:

the motor torque detection module can be used for detecting the output torque of the motor during operation as the real-time torque of the motor. For example: real-time torque T of motor rotor_eThe sampling can be obtained by a sensing module of a permanent magnet synchronous motor speed regulating system. As in the torque-power detection module, the torque detection module is used for detecting the real-time output torque T when the motor runs_e。

And the first multiplier can be used for taking the product of the real-time torque of the motor and the given rotating speed of the motor as the given power of the motor at the given rotating speed of the motor.

For example: motor rotor real-time torque T obtained by collection_eAnd calculating the running power P of the motor under the condition of the given rotating speed according to the current given rotating speed omega of the motor, wherein the mechanical power calculation formula of the calculation method, such as the motor running, is shown as the formula (1): p ═ ω × T_e(1). In formula (1), P is the running power of the motor, omega is the given rotating speed of the motor, and T_eThe real-time torque of the motor rotor under the condition of a given rotating speed is adopted.

Therefore, the given power of the motor under the given rotating speed condition is calculated by utilizing the real-time torque of the motor and the given rotating speed of the motor, which are obtained by detection, so that an accurate basis can be provided for calculating the given q-axis current reference value of the motor, and the accuracy of determining the given q-axis current reference value of the motor in the process of inhibiting the rotating speed integral saturation phenomenon is improved.

A current determination module (e.g., an equivalent current calculation module) may be configured to determine a given q-axis current reference value for the electric machine based on the given power. For example: and the equivalent current calculation module is used for calculating the q-axis current reference value of the motor under the condition of a given rotating speed through the given power of the motor output by the motor torque-power conversion module, so that the motor can normally operate, but the equivalent current calculation module is small enough to ensure that the q-axis current reference value cannot enter a saturation region.

More optionally, the current determining module (e.g., equivalent current calculating module) may include: the device comprises a direct current bus voltage detection module, a voltage processing module and a second multiplier.

Accordingly, the determining a given q-axis current reference value of the motor by the current determining module (e.g., equivalent current calculating module) based on the given power may include:

the direct current bus voltage detection module can be used for detecting the maximum value of the direct current side bus voltage of the motor speed regulating system to obtain the maximum value of the direct current bus voltage. For example: the rotational speed saturation suppression unit is used for detecting the maximum value of the DC side bus voltage, such as the maximum value U of the DC side bus voltage_maxAnd the voltage is obtained by sampling through a voltage sampling module of the permanent magnet synchronous motor speed regulating system.

And the voltage processing module can be used for performing reciprocal and proportion calculation processing on the maximum value of the direct-current bus voltage to obtain the reciprocal of the maximum value of the direct-current side bus voltage with the proportion coefficient. For example: and the voltage processing module performs reciprocal and proportional calculation processing on the maximum value of the detected direct-current side bus voltage so as to complete the subsequent current calculation process. The maximum value of the voltage of a direct-current side bus of the motor vector control system is obtained by using the rotating speed saturation suppression unit, the maximum value is input into the voltage processing module, and the maximum reference voltage required by the calculation of the q-axis current reference value is obtained according to the q-axis current reference value minimization principle. Specifically, according to the power equivalent principle of the speed regulating system of the permanent magnet synchronous motor, under an ideal condition without considering conditions such as friction loss, the relationship, as shown in formula (2), of the motor electric power calculation formula exists between the operating power of the permanent magnet synchronous motor and the d-q axis current and d-q axis voltage of the motor:

P＝1.5(u_di_d+u_qi_q) (2)。

the real-time torque T of the motor rotor can be obtained by combining the formula (1) and the formula (2)_eGiven the relationship between the rotational speed ω and the d-q axis current and voltage of the motor, as shown in equation (3):

ω×T_e＝1.5(u_di_d+u_qi_q) (3)。

by combining the formula (1) and the formula (2), the mechanical power and the electric power are equalized to calculate the required parameters.

And the second multiplier can be used for determining the product of the given power and the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient as a q-axis current reference value of the motor at the given rotating speed of the motor. For example: the multiplier multiplies the given power P of the motor output by the torque-power detection module by the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient output by the voltage processing module to obtain a q-axis current reference value i which cannot enter a saturation range under the condition of a given rotating speed_qref. And calculating to obtain a q-axis current reference value of the permanent magnet synchronous motor under the given rotating speed condition by utilizing the maximum reference voltage and the power of the permanent magnet synchronous motor under the given rotating speed condition. In particular, vector control systems for permanent magnet synchronous machines generally apply a maximum torque control strategy, i.e. i_dControl strategy is 0. Therefore, when parameter calculation is carried out in a motor rotating speed saturation dynamic module, i is applied_dAfter the strategy of 0, the mathematical relation expression of equation (3) can be further simplified, and the simplified mathematical relation expression is shown in equation (4):

ω×T_e＝1.5u_qi_q (4)。

by combining formula (1) with formula (2), using i_d0 principle to calculate i_qA reference value.

The magnitude of the q-axis current reference value at a given rotation speed can be determined by equation (4). The q-axis current reference value is calculated as shown in equation (5):

wherein i is calculated by the formula (5)_qrefThe bus voltage is at the maximum value on the DC side (i.e., u_qIn the maximum state). From the power calculation method, when the power P of the motor is given, P ═ u_q×i_qref，i_qrefI.e. i in the formula (4)_qThen u is_qAnd i_qrefIn inverse proportion if i is_qrefRelatively small so as not to enter the saturation region, u_qShould take a large value, so in this part of the calculation, u_qThe maximum value of the DC side bus voltage is obtained, namely no matter what power condition the motor works under, the driving voltage of the motor can not exceed the maximum value u of the DC side bus voltage_q。

Given q-axis current i output by rotating speed PI regulator_qObtained by a central control chip in the control system by calculating variables such as given rotating speed and actual rotating speed i_qAnd the rotation speed is a control object of the rotation speed saturation dynamic suppression module. In a permanent magnet synchronous motor driving system, factors such as circuit loss are ignored, and the motor running power is approximately equal to the inverter power, that is, the dc side bus power, as shown in formula (6):

U_dcI_dc＝P_dc＝P_inv≈P_motor (6)。

the power equivalent calculation algorithm is adopted, the formula (6) is used for supplementing the theory of the formula (5), namely the direct-current side bus power can be determined through the motor power, and then the q-axis current reference value i is calculated through the maximum value of the direct-current side bus voltage_qref。

In formula (6), U_dcIs a DC side bus voltage, I_dcIs a direct-side bus current, P_dcFor the DC side bus power, P_invTo inverter power, P_motorIs the motor power. As can be seen from the expressions (4), (5) and (6), if the predetermined rotational speed is input and the q-axis current i is converted to the predetermined value_qAnd the given q-axis voltage value of the motor further converted reaches the DC side bus voltage U_dcWhen the voltage of the motor is not regulated by the control system, the motor control system is in a voltage saturation state, and the regulation capacity of the system is greatly reduced. Since the given q-axis voltage is determined by the given q-axis current i_qObtained by conversion, so that when a q-axis current i is given_qWhen the voltage of the given q axis is too large, the voltage of the given q axis is too large until the voltage of the given q axis is upWhen the voltage rises to the saturation region, the voltage saturation phenomenon occurs, and therefore the voltage saturation phenomenon and the rotation speed saturation phenomenon occur in the same manner. To suppress the rotation speed saturation phenomenon, i_qIs limited to the outside of the saturation region, u in formula (5)_qCan be determined as the DC side bus voltage U_dcMaximum value of (1), is noted as U_maxAt this time, since the motor power has already been determined, and u_q＝U_maxIs the maximum voltage, i thus calculated_qrefFor the minimum value of q-axis current of normal operation of the motor under the given power condition, i_qrefFor reference, a given q-axis current i may be obtained_qNot too large to enter the amplitude limit of the saturation interval.

U_maxObtained by sampling with a voltage sensor, U_maxAfter the value of (5) is determined, the q-axis current reference value i under the given rotating speed condition can be calculated by using the formula (5)_qrefThe size of (2). Since the output variable of the PI regulator during regulation fluctuates between positive and negative directions of a given value before reaching a steady state to realize feedback regulation of the actual rotation speed, the q-axis current reference value i cannot be adjusted_qrefAs limiting the amplitude range of the output variable of the rotational speed PI regulator, which leads to i before reaching steady state_qLoss of dynamic accommodation space. To reference the value i with the q-axis current_qrefAs a reference, i is_qrefAmplifying the positive direction and the negative direction of the coordinate axis by a reasonable proportion multiple K, so that the control system fluctuates up and down in a reasonable interval outside the saturation interval, and the control system achieves the effect of dynamic adjustment.

For example: when the given power of the motor is determined, the given q-axis current reference value and the given q-axis voltage are in inverse proportion, in order to enable the given q-axis current reference value not to exceed a limit range, the calculated value of the given q-axis voltage is determined according to the maximum value in a reasonable interval, and the maximum value of the direct-current side bus voltage of the control system or the maximum value of the rated driving voltage of the motor can be used as the given q-axis voltage to calculate the given q-axis current reference value of the motor. Therefore, the current reference value which can enable the motor to normally operate under the current given rotating speed condition but is small enough to ensure that the current reference value cannot enter a saturation interval is used as the q-axis current reference value.

Therefore, the given q-axis current reference value of the motor is further calculated by utilizing the given power of the motor under the given rotating speed condition, an accurate basis is provided for determining the amplitude limit upper limit and the amplitude limit lower limit of the dynamic amplitude limit module, and the accuracy of determining the amplitude limit upper limit and the amplitude limit lower limit in the process of restraining the rotating speed integral saturation phenomenon is favorably improved.

And the amplitude limiting module (such as a dynamic amplitude limiting module) can be used for determining the upper limit of the amplitude limiting range and the lower limit of the amplitude limiting range of the output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference so as to limit the dynamic change range of the output variable of the rotating speed PI regulator within the dynamic change amplitude limiting range. The dynamic amplitude limiting module is composed of a maximum amplitude limiting module and a minimum amplitude limiting module. The dynamic amplitude limiting module is configured at the output end of the rotating speed PI regulator and used for limiting the amplitude of the output variable of the rotating speed PI regulator. By adopting a dynamic amplitude suppression mode, the problem that the output variable tracking of the rotating speed PI regulator is inaccurate when the motor runs at high power and is generated by an amplitude limiting module with a fixed threshold value can be solved; and, the low-power operation of the motor can be improved, and the specific i_qThe amplitude limiting module cannot realize the amplitude limiting function.

For example: given motor q-axis current i to output variable of rotating speed loop PI regulator in double closed loop type vector control system_qLimiting the upper limit and the lower limit of the amplitude to prevent the upper limit and the lower limit of the amplitude from being excessively large in the positive direction or excessively small in the negative direction to cause i_qAnd when the motor enters a saturation interval, the integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system is inhibited. If the motor power under the given rotating speed condition can be obtained by calculating through sampling the real-time torque of the permanent magnet synchronous motor rotor and the maximum value of the direct-current side bus voltage, and then the q-axis voltage reference value corresponding to the given rotating speed is obtained by further calculating; determining the upper limit and the lower limit of a rotating speed PI regulator amplitude limiting module by using a given q-axis voltage reference valueAnd limiting the given q-axis current output by the rotating speed PI regulator outside a rotating speed integral saturation region, and inhibiting the generation of a rotating speed saturation phenomenon.

For example: calculating the running power of the motor under the current rotating speed condition according to the given rotating speed and the actual load torque of the motor, thereby calculating and obtaining a given q-axis current reference value of the motor; and adjusting the output amplitude limiting range of the rotating speed PI adjuster according to a given motor q-axis current reference value, so as to realize full-band dynamic saturation suppression of the motor speed adjusting system on the rotating speed of the motor. In addition, when the motor enters a field weakening acceleration state, the d-axis current of the motor is increased, and the q-axis current of the motor is reduced so that the rotating speed of the motor is further increased under the condition of the maximum power. In the processes of increasing the d-axis current and reducing the q-axis current, the d-q-axis current generates dynamic change due to the increase of the rotating speed, rotating speed and current errors in the dynamic process are generated, and after the errors are subjected to integral amplification by the PI regulator, the motor still possibly generates an integral saturation phenomenon. According to the scheme of the invention, when the motor enters a weak magnetic speed-up state, the d-q axis current of the permanent magnet synchronous motor can be limited within a safety range, the occurrence of an overcurrent phenomenon is avoided, and the stability and reliability of a motor speed regulating system are improved.

Therefore, the given power of the motor under the given rotating speed condition is calculated by utilizing the real-time torque of the motor and the given rotating speed of the motor which are obtained by detection; the given q-axis current reference value of the motor is further calculated by using the given power, the amplitude limit upper limit and the amplitude limit lower limit of the dynamic amplitude limit module are determined by taking the given q-axis current reference value as a reference, the output variable of the rotating speed loop PI regulator can be ensured to change within the amplitude limit range and not exceed the regulation range of the control system, the rotating speed integral saturation phenomenon is inhibited, and the stability of the vector control system is improved.

More optionally, the amplitude limiting module (e.g., dynamic amplitude limiting module) may include: the device comprises a proportion calculation module, a reverse control module, a maximum amplitude limiting module and a minimum amplitude limiting module.

Accordingly, the determining, by the amplitude limiting module (e.g., dynamic amplitude limiting module), an upper limit of an amplitude limiting range and a lower limit of the amplitude limiting range of the output variable of the rotational speed PI regulator based on the given q-axis current reference value may include:

the proportion calculation module may be configured to multiply the given q-axis current reference value by a set scaling factor to obtain a product of the given q-axis current reference value and the set scaling factor. For example: the proportion calculation module is used for calculating a q-axis current reference value i_qrefAmplified to Ki by a proportionality factor K_qrefAnd the proportionality coefficient K is set according to actual motor parameters and system control requirements. And inputting the obtained q-axis current reference value into a proportion calculation module to obtain the maximum reference current after proportion amplification. Specifically, the q-axis current is referenced to the value i_qrefAn input proportion calculation module for carrying out proportion calculation to obtain i output by the rotating speed PI regulator_qUpper limit of amplitude limitation Ki_qref. And K is a proportionality coefficient in the proportion calculation module. The determination method of the proportionality coefficient K is different for permanent magnet synchronous motors with different models and structures. In the rotation speed saturation dynamic suppression module introduced by the method, the value of the proportionality coefficient K is 2 according to the mathematical relation of rotation speed frequency-bandwidth.

And the reverse control module can be used for converting the direction of the product of the given q-axis current reference value and the set proportionality coefficient to obtain the reverse product of the given q-axis current reference value and the set proportionality coefficient. For example: the reverse rotation speed saturation suppression unit is used for limiting the current reference value Ki_qrefThe direction of (d) is switched to the negative direction. And inputting the maximum reference current into a reverse rotation speed saturation suppression unit to obtain the negative minimum reference current. Specifically, i calculated by a proportion calculation module_qUpper limit of amplitude limitation Ki_qrefInput into a reverse rotation speed saturation suppression unit to obtain i_qLower limit of amplitude limit-K_iqref。

And the maximum amplitude limiting module can be used for taking the product of the given q-axis current reference value and a set proportionality coefficient as the upper limit of the amplitude limiting range of the output variable of the rotating speed PI regulator. For example: and the maximum amplitude limiting module is used for determining and limiting the upper limit of the output variable of the rotating speed PI regulator. Amplitude limit of maximum amplitude limit moduleThe limit is obtained by multiplying a given q-axis current reference value output by the equivalent current calculation module by a proportionality coefficient; when the given q-axis current reference value changes, the amplitude limit upper limit of the maximum amplitude limit module changes according to the given q-axis current reference value, so that dynamic control over the amplitude limit upper limit is realized. The maximum amplitude limiting module is a limiting circuit which uses Ki_qrefLimiting the amplitude of the output variable of the rotating speed PI regulator to be not higher than Ki as the upper limit of the amplitude_qref。

And the minimum amplitude limiting module can be used for taking the product of the inverted given q-axis current reference value and a set proportionality coefficient as the lower limit of the amplitude limiting range of the output variable of the rotating speed PI regulator. For example: and the minimum amplitude limiting module is used for determining and limiting the lower limit of the output variable of the rotating speed PI regulator. The amplitude limit lower limit of the minimum amplitude limit module is obtained by multiplying a given q-axis current reference value output by the equivalent current calculation module by a proportionality coefficient and changing the current reference direction by using a reverse rotation speed saturation suppression unit, and when the given q-axis current reference value is changed, the amplitude limit lower limit of the minimum amplitude limit module is changed according to the given q-axis current reference value so as to realize the dynamic control of the amplitude limit lower limit. The minimum amplitude limiting module is a limiting circuit with-Ki_qrefLimiting the amplitude of the output variable of the rotating speed PI regulator to be not lower than-Ki for the lower limit of the amplitude_qref。

The maximum reference current and the minimum reference current are respectively input into the maximum amplitude limiting module and the minimum amplitude limiting module, and the amplitude limiting circuits in the two groups of amplitude limiting modules use the input maximum reference current and the input minimum reference current as the upper limit and the lower limit of the amplitude limiting range. The amplitude limiting module limits the output variable of the rotating speed PI regulator to be outside a rotating speed integral saturation area, and the rotating speed integral saturation phenomenon is restrained. Specifically, i is_qThe amplitude limit upper limit and the amplitude limit lower limit are respectively input into the maximum amplitude limit module and the minimum amplitude limit module, so that the maximum amplitude limiting circuit and the minimum amplitude limiting circuit use Ki_qrefto-Ki_qrefTo limit range operation, limit i_qOutput range of x. Is limited byAmplitude modulated i_qWill be input into the current loop to complete the subsequent control process.

For example: a dynamic amplitude limiting module: since the output variable of the PI regulator during regulation fluctuates between positive and negative directions of a given value before reaching a steady state to realize feedback regulation of the actual rotation speed, the q-axis current reference value i cannot be adjusted_qrefAs limiting the amplitude range of the output variable of the rotational speed PI regulator, which leads to i before reaching steady state_qLoss of dynamic accommodation space. But rather to use i_qrefAs a reference, i is_qrefAmplifying the positive direction and the negative direction of the coordinate axis by a reasonable proportion multiple K, so that the control system fluctuates up and down in a reasonable interval outside the saturation interval, and the control system achieves the effect of dynamic adjustment. The output range of the rotational speed PI regulator is limited to-Ki_qrefTo Ki_qrefIn the meantime. Since this amplitude range is limited by calculation outside the saturation region, a given q-axis current i is output by the rotational speed PI regulator_qThe integral saturation phenomenon is suppressed, and the reference value i of the current is limited_qrefThe method can be changed according to the change of the running power of the motor, and the dynamism of the integral saturation suppression process is realized.

Therefore, the upper limit and the lower limit of the amplitude limit of the dynamic amplitude limit module are determined by taking the given q-axis current reference value as a reference, so that the rotation speed integral saturation phenomenon can be inhibited, and the stability of the vector control system is improved.

In an optional embodiment, the rotation speed saturation suppression unit may be further configured to dynamically suppress a given q-axis voltage amplitude output by the current PI regulator in the current loop in a case where a rotation speed saturation phenomenon generated during a motor speed increase process is dynamically suppressed.

For example: the adopted dynamic amplitude suppression method outputs variable i to the rotating speed ring_qAmplitude limiting is carried out to prevent the rotation speed from entering a saturation interval, and a variable i is output by a rotation speed ring_qThe upper limit and the lower limit of the variation amplitude are obtained by calculating and processing the maximum value of the motor power and the voltage of the direct-current side bus, and the control mode can ensure that the subsequent d-q shaft output voltage cannot be generatedThe voltage saturation phenomenon is generated when the voltage is higher than the maximum value of the direct-current side bus voltage, and the problem of the d-q axis voltage saturation phenomenon of the motor caused by errors generated by the rotating speed integral saturation phenomenon in a vector control system of the permanent magnet synchronous motor is solved. Under the condition of a given rotating speed of the motor, a given q-axis current output by the rotating speed PI regulator is processed by the dynamic amplitude limiting module and then is input into the current loop as an input variable of the current loop to execute a subsequent control process. Because the input variable of the current loop, namely the given q-axis current amplitude, is limited outside the saturation region, the given q-axis voltage amplitude output by the current PI regulator in the current loop cannot enter the saturation region, and a voltage amplitude limiting module which is configured at the output end of the current loop PI regulator and used for controlling the given d-q-axis voltage value output by the PI regulator not to enter the saturation region can be cancelled, so that the structure of a controllable system is simplified, and the control performance is improved.

Therefore, under the condition of dynamically inhibiting the rotating speed saturation phenomenon generated in the motor acceleration process, the given q-axis voltage amplitude output by the current PI regulator in the current loop is dynamically inhibited, the given q-axis voltage amplitude output by the current PI regulator in the current loop is ensured not to enter a saturation region, a voltage saturation limiting module at the output end of the current PI regulator can be omitted, the structure of the double closed-loop vector control system can be simplified, and the control performance is improved.

Through a large number of tests, the technical scheme of the invention is adopted, and the output variable of a rotating speed loop PI regulator in the double closed loop type vector control system, namely the q-axis current i of a given motor, is measured_qLimiting the upper limit and the lower limit of the amplitude to prevent the upper limit and the lower limit of the amplitude from being excessively large in the positive direction or excessively small in the negative direction to cause i_qAnd entering a saturation interval to control the output variable of the rotating speed PI regulator in a reasonable variation range, inhibit the integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system, and be beneficial to improving the running stability of the motor.

According to the embodiment of the invention, a motor speed regulating system corresponding to the rotating speed control device is also provided. The motor speed regulation system may include: the rotational speed control device described above.

The PI regulator is a linear control system, while the permanent magnet synchronous motor is a nonlinear multivariable multi-parameter coupling system, and in the motor control process, the PI regulator is continuously influenced by parameter change and system disturbance of the permanent magnet synchronous motor, and the regulation capability and stability of the PI regulator are reduced. In the starting process and the weak magnetic speed increasing process of the motor, the PI regulator utilizes an error integral regulating module to eliminate static errors in a control system, the accumulation of the errors can cause the integral saturation phenomenon of a rotating speed loop and a current loop, when the integral saturation phenomenon occurs, a control variable of the control system enters a nonlinear interval, the PI regulator cannot enable a control signal to follow a given signal, the error of the control system is increased, the control response time is greatly increased, and even the motor enters an out-of-control state.

In order to inhibit the integral saturation phenomenon and keep the motor in a normal working state, certain amplitude limitation needs to be carried out on the output variable of the PI regulator, so that the output variable of the PI regulator is kept in a reasonable range, and meanwhile, a control system reserves a certain regulation space to process the control variable. In general, a method for solving the integral saturation phenomenon is to add an amplitude limiting module at the output end of a d-q axis current PI regulator and carry out amplitude limiting processing on an output variable of the PI regulator. The control method can inhibit the integral saturation phenomenon in a certain range, but in the variable-frequency compressor motor speed regulating system, the rotating speed of the motor changes, so the running power, the driving voltage and the d-q axis current of the motor change along with the change of the rotating speed, and the output variables of a rotating speed PI regulator and a current PI regulator in the variable-frequency speed regulating system are not fixed values but dynamic variables changing along with the rotating speed. Aiming at the variable output variable of the PI regulator, the amplitude limiting module with a fixed threshold value cannot well solve the problem of integral saturation, and if the threshold value of the amplitude limiting module is too low, the PI regulator cannot accurately track the output variable when the rotating speed is increased and the power of the motor is increased; if the threshold value of the amplitude limiting module is too high, the amplitude limiting module will fail when the rotating speed is reduced and the motor power is reduced, and the rotating speed integral saturation phenomenon still occurs.

In addition to the suppression of the motor speed integral saturation phenomenon by using the regulator output variable amplitude limiting method, a low-gain saturation regulator control method based on the Lyapunov function can also be used for suppressing the motor speed saturation phenomenon, and the principle is that the saturation gain of a control system is reduced by improving the system structure of a speed regulator, so that the motor speed saturation phenomenon is suppressed. However, the Lyapunov function-based low-gain saturation regulator control method needs to establish a parameter matrix of a control variable, the control process is large in calculation amount and complex in calculation method, and when the method is applied to a variable frequency motor speed regulating system, the response speed and the complexity of the control system are greatly increased.

In an optional embodiment, the invention provides a new rotational speed integral saturation suppression method, and specifically may be a dynamic rotational speed saturation suppression method for a permanent magnet synchronous motor. The control method can control the output variable of the rotating speed PI regulator within a reasonable variation range, and prevent the rotating speed saturation phenomenon caused by error integration of the PI regulator; meanwhile, when the rotating speed of the motor is changed, the control system can adjust the amplitude limit range of the output variable of the PI regulator according to the current rotating speed of the motor without changing the system structure and system parameters, so that the dynamic amplitude control of the output variable of the PI regulator is realized, and the control performance of the motor speed regulating system is improved. The integral saturation phenomenon of the rotating speed is dynamically inhibited by the variable frequency motor vector control system under different given rotating speed conditions, so that the stability of the vector control system is improved, and at least the problem that some vector control systems cannot adjust the amplitude limit range of the saturation inhibition module at the output end of the rotating speed PI regulator according to the change of the rotating speed of the motor can be solved.

Specifically, according to the scheme of the invention, the running power of the motor under the current rotating speed condition can be calculated according to the given rotating speed and the actual load torque of the motor, so that the given q-axis current reference value of the motor is calculated; and adjusting the output amplitude limiting range of the rotating speed PI adjuster according to a given motor q-axis current reference value, so as to realize full-band dynamic saturation suppression of the motor speed adjusting system on the rotating speed of the motor. In addition, when the motor enters a field weakening acceleration state, the d-axis current of the motor is increased, and the q-axis current of the motor is reduced so that the rotating speed of the motor is further increased under the condition of the maximum power. In the processes of increasing the d-axis current and reducing the q-axis current, the d-q-axis current generates dynamic change due to the increase of the rotating speed, rotating speed and current errors in the dynamic process are generated, and after the errors are subjected to integral amplification by the PI regulator, the motor still possibly generates an integral saturation phenomenon. According to the scheme of the invention, when the motor enters a weak magnetic speed-up state, the d-q axis current of the permanent magnet synchronous motor can be limited within a safety range, the occurrence of an overcurrent phenomenon is avoided, and the stability and reliability of a motor speed regulating system are improved.

In an alternative example, the scheme of the invention adopts a dynamic amplitude limiting method to give q-axis current i of a motor to an output variable of a rotating speed loop PI regulator in a double closed loop type vector control system_qLimiting the upper limit and the lower limit of the amplitude to prevent the upper limit and the lower limit of the amplitude from being excessively large in the positive direction or excessively small in the negative direction to cause i_qAnd when the integral saturation interval is entered, the integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system is inhibited, and the problem of integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system is solved.

Further optionally, in the scheme of the present invention, a dynamic amplitude suppression method is adopted, and the output variable i of the rotation speed PI regulator is calculated and processed by the motor power under different given rotation speeds_qThe upper limit and the lower limit of the amplitude are changed according to the change of the motor power under different given rotating speed conditions, so that the inhibition range of a given q-axis current saturation interval is dynamically changed along with the power when the power of the motor is changed, and the problem that the rotating speed of the motor cannot be accurately controlled due to the fact that the amplitude limit range of an amplitude limit module at the output end of a rotating speed PI regulator in a permanent magnet synchronous motor vector control system cannot be adjusted according to the change of the rotating speed is solved.

In a conventional vector control system, an amplitude limiting module with a fixed amplitude limiting value is often used for performing saturation limitation on an output variable of a PI regulator, and an amplitude upper limit value and an amplitude of the limiting moduleThe lower degree limit is determined and does not vary with the input variables of the control system. When the motor runs at high power, the limiting range of the limiting module with specific amplitude is possibly too small, so that the output variable of the rotating speed PI regulator cannot be increased or reduced to a value required by a system, and the output variable of the rotating speed PI regulator cannot accurately complete the tracking control process; when the motor operates at low power, the limiting range of the limiting module with specific amplitude is possibly overlarge, the limiting module cannot limit the output variable of the PI regulator at the moment, and the rotation speed saturation phenomenon can still be caused by the output variable which is not limited. The dynamic amplitude suppression method can better solve the problems. Compared with some specific i_qThe invention relates to an amplitude range limiting method, in particular to a dynamic amplitude suppression method adopted by the scheme of the invention, which can solve the problem that the tracking of the output variable of a rotating speed PI regulator is inaccurate when a motor runs at high power and is generated by an amplitude limiting module with a fixed threshold value. And, the low-power operation of the motor can be improved, and the specific i_qThe amplitude limiting module cannot perform amplitude limiting operation. .

Further optionally, in the scheme of the present invention, the adopted dynamic amplitude suppression method outputs variable i to the rotation speed loop_qAmplitude limiting is carried out to prevent the rotation speed from entering a saturation interval, and a variable i is output by a rotation speed ring_qThe upper limit and the lower limit of the variation amplitude are obtained by calculating and processing the maximum value of the motor power and the maximum value of the direct-current side bus voltage, the control mode can ensure that the subsequent d-q axis output voltage is not higher than the maximum value of the direct-current side bus voltage to generate a voltage saturation phenomenon, and the problem of the motor d-q axis voltage saturation phenomenon further caused by errors generated by the rotation speed integral saturation phenomenon in a permanent magnet synchronous motor vector control system is solved.

Therefore, the vector control system applying the dynamic amplitude suppression method can cancel a voltage amplitude limiting module which is configured at the output end of the current loop PI regulator and used for controlling the given d-q axis voltage value output by the PI regulator not to enter the saturation region, thereby simplifying the control process.

In an optional embodiment, the dynamic suppression method for the rotation speed saturation of the vector control system of the permanent magnet synchronous motor according to the aspect of the present invention may be composed of a rotation speed loop and current loop double closed loop vector control method, where the rotation speed loop employs a rotation speed saturation suppression unit, and the rotation speed saturation suppression unit can apply the dynamic suppression method for the rotation speed saturation of the speed regulation system of the variable frequency permanent magnet synchronous motor to suppress the rotation speed saturation phenomenon generated in the motor speed increasing process.

In an optional example, the rotation speed saturation suppression unit, that is, the rotation speed saturation dynamic suppression module, applying the rotation speed saturation dynamic suppression method of the variable frequency permanent magnet synchronous motor speed regulation system may include: the system comprises a motor torque-power conversion module, an equivalent current calculation module and a dynamic amplitude limiting module. The set of rotating speed saturation suppression units calculate the given power of the motor under the given rotating speed condition by using the real-time torque of the motor and the given rotating speed of the motor which are obtained by detection; and further calculating a given q-axis current reference value of the motor by using the given power, and determining an amplitude limit upper limit and an amplitude limit lower limit of the dynamic amplitude limiting module by taking the given q-axis current reference value as a reference. The amplitude limiting module can ensure that the output variable of the rotating speed loop PI regulator changes within the amplitude limiting range and does not exceed the regulating range of the control system, the rotating speed integral saturation phenomenon is inhibited, and the stability of the vector control system is improved.

Alternatively, the motor torque-power conversion module may be composed of a motor torque detection module and a multiplier. And the motor torque-power conversion module can detect the output torque when the motor runs. The output torque of the motor and the given rotating speed are input into the multiplier, and the given power of the motor under the given rotating speed condition can be obtained.

Further optionally, the equivalent current calculating module calculates a q-axis current reference value of the motor at a given rotation speed by using the given power of the motor output by the motor torque-power conversion module. When the given power of the motor is determined, the given q-axis current reference value and the given q-axis voltage are in inverse proportion, in order to enable the given q-axis current reference value not to exceed a limit range, the calculated value of the given q-axis voltage is determined according to the maximum value in a reasonable interval, and the maximum value of the direct-current side bus voltage of the control system or the maximum value of the rated driving voltage of the motor can be used as the given q-axis voltage to calculate the given q-axis current reference value of the motor.

Further optionally, the dynamic amplitude limiting module is composed of a maximum amplitude limiting module and a minimum amplitude limiting module. The dynamic amplitude limiting module is configured at the output end of the rotating speed PI regulator and used for limiting the amplitude of the output variable of the rotating speed PI regulator.

More optionally, the maximum amplitude limiting module is configured to determine and limit an upper limit of an output variable of the rotational speed PI regulator. The amplitude limit upper limit of the maximum amplitude limit module is obtained by multiplying a given q-axis current reference value output by the equivalent current calculation module by a proportionality coefficient; when the given q-axis current reference value changes, the amplitude limit upper limit of the maximum amplitude limit module changes according to the given q-axis current reference value, so that dynamic control over the amplitude limit upper limit is realized.

More optionally, the minimum amplitude limiting module is configured to determine and limit a lower limit of an output variable of the rotational speed PI regulator. The amplitude limit lower limit of the minimum amplitude limit module is obtained by multiplying a given q-axis current reference value output by the equivalent current calculation module by a proportionality coefficient and changing the current reference direction by using a reverse rotation speed saturation suppression unit, and when the given q-axis current reference value is changed, the amplitude limit lower limit of the minimum amplitude limit module is changed according to the given q-axis current reference value so as to realize the dynamic control of the amplitude limit lower limit.

And under the condition of a given rotating speed of the motor, the given q-axis current output by the rotating speed PI regulator is processed by the dynamic amplitude limiting module and then is input into the current loop as an input variable of the current loop to execute a subsequent control process. The current loop may employ conventional PI control methods. In the scheme of the invention, the input variable of the q-axis current loop PI regulator is a given q-axis current i subjected to dynamic saturation suppression_qAnd the actual q-axis current i_qGiven a q-axis current i_qIs based on the DC bus voltage reaching a maximum value, and i_dThe control strategy of 0 is amplitude-limited, so that the output variable of the q-axis current loop PI regulator isq-axis given voltage U_qThe amplitude of the signal is also restrained to a certain degree, U_qThe amplitude of the signal will not exceed the maximum value of the voltage of the direct current side bus and enter a voltage saturation state. For the above reasons, in the scheme of the present invention, a voltage saturation limiting module at the output terminal of the current PI regulator in the conventional current loop PI control method can be omitted, the structure of the control system is simplified, and the control performance is improved.

In an alternative embodiment, a specific implementation process of the scheme of the present invention can be exemplarily described with reference to the examples shown in fig. 2 to fig. 7.

Fig. 2 is a schematic structural diagram of an embodiment of a permanent magnet synchronous motor speed regulating system to which the motor rotation speed saturation dynamic suppression method of the present invention is applied. In fig. 2, a rotational speed saturation dynamic suppression module applying the motor rotational speed saturation dynamic suppression method of the present invention is added to the output end of the rotational speed PI regulator.

Fig. 3 is a schematic structural diagram of a rotational speed saturation dynamic suppression module according to an embodiment of the present invention. In fig. 3, three groups of modules in a dashed line frame are structural parts of a rotational speed integral saturation dynamic rotational speed saturation suppression unit in the scheme of the present invention, and are an important control structure of the present invention; the dotted line block diagram is externally divided into a rotating speed loop closed-loop error tracking feedback unit and a PI regulator module (namely, a rotating speed PI regulator) of the vector control system, and the part is a partial structure in the traditional vector control system.

Referring to the example shown in fig. 3, in the torque-power detection module, the torque detection module is used for detecting the real-time output torque T when the motor operates_eAnd the multiplier is used for calculating the given power P of the motor under the current given rotating speed condition.

Referring to the example shown in fig. 3, the equivalent current calculation module is used to calculate a q-axis current reference value that enables the motor to operate normally at the current given rotation speed, but is small enough to ensure that the q-axis current reference value does not enter the saturation range. The direct current bus rotating speed control unit is used for detecting the maximum value of the direct current side bus voltage; the voltage processing module performs reciprocal and proportional calculation processing on the maximum value of the detected direct-current side bus voltage for finishingForming a subsequent current calculation process; the multiplier multiplies the given power P of the motor output by the torque-power detection module by the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient output by the voltage processing module to obtain a q-axis current reference value i which cannot enter a saturation range under the condition of a given rotating speed_qref。

Referring to the example shown in fig. 3, the dynamic amplitude limiting module: since the output variable of the PI regulator during regulation fluctuates between positive and negative directions of a given value before reaching a steady state to realize feedback regulation of the actual rotation speed, the q-axis current reference value i cannot be adjusted_qrefAs limiting the amplitude range of the output variable of the rotational speed PI regulator, which leads to i before reaching steady state_qLoss of dynamic accommodation space. But rather to use i_qrefAs a reference, i is_qrefAmplifying the positive direction and the negative direction of the coordinate axis by a reasonable proportion multiple K, so that the control system fluctuates up and down in a reasonable interval outside the saturation interval, and the control system achieves the effect of dynamic adjustment. The proportion calculation module is used for calculating a q-axis current reference value i_qrefAmplified to Ki by a proportionality factor K_qrefThe proportionality coefficient K is set according to actual motor parameters and system control requirements; the maximum amplitude limiting module is a limiting circuit which uses Ki_qrefLimiting the amplitude of the output variable of the rotating speed PI regulator to be not higher than Ki as the upper limit of the amplitude_qref(ii) a The reverse control unit is used for limiting the current reference value Ki_qrefThe direction of (3) is changed to the negative direction; the minimum amplitude limiting module is a limiting circuit with-Ki_qrefLimiting the amplitude of the output variable of the rotating speed PI regulator to be not lower than-Ki for the lower limit of the amplitude_qref(ii) a The output range of the rotational speed PI regulator is limited to-Ki_qrefTo Ki_qrefIn the meantime. Since this amplitude range is limited by calculation outside the saturation region, a given q-axis current i is output by the rotational speed PI regulator_qThe integral saturation phenomenon is suppressed, and the reference value i of the current is limited_qrefThe method can be changed according to the change of the running power of the motor, and the dynamism of the integral saturation suppression process is realized.

Fig. 4 is a control flow diagram of a rotational speed saturation dynamic suppression module according to an embodiment of the present invention. According to the rotation speed saturation dynamic suppression method for the permanent magnet synchronous motor vector control system, provided by the scheme of the invention, under the condition of a given rotation speed, the motor power under the condition of the given rotation speed is obtained by calculating through sampling the real-time torque of a permanent magnet synchronous motor rotor and the maximum value of the direct-current side bus voltage, and then the q-axis voltage reference value corresponding to the given rotation speed is obtained by further calculating; and determining the upper limit and the lower limit of the amplitude limiting module of the rotating speed PI regulator by using the given q-axis voltage reference value, limiting the given q-axis current output by the rotating speed PI regulator outside a rotating speed integral saturation region, and inhibiting the generation of a rotating speed saturation phenomenon. As shown in fig. 4, the control flow of the rotation speed saturation dynamic suppression module may include:

the method comprises the following steps of 1, obtaining a given rotating speed of the permanent magnet synchronous motor, obtaining an output torque of the permanent magnet synchronous motor under the condition of the given rotating speed by using a motor torque detection module, inputting the given rotating speed and the output torque of the permanent magnet synchronous motor into a multiplier, and obtaining the power of the permanent magnet synchronous motor under the condition of the given rotating speed. Wherein, step 1 may specifically include:

and 11, collecting circuit parameters required by the rotating speed saturation suppression unit. The circuit parameters required by the method of the invention are as follows: a. real-time torque T of motor rotor_eSampling and obtaining the signals by a sensing module of a speed regulating system of the permanent magnet synchronous motor; b. maximum value U of DC side bus voltage_maxSampling and obtaining the voltage by a voltage sampling module of a permanent magnet synchronous motor speed regulating system; c. given q-axis current i output by speed regulator_qObtained by a central control chip in the control system by calculating variables such as given rotating speed and actual rotating speed i_qAnd the rotation speed is a control object of the rotation speed saturation dynamic suppression module.

Step 12, utilizing the collected real-time torque T of the motor rotor_eAnd calculating the running power P of the motor under the condition of the given rotating speed according to the current given rotating speed omega of the motor, wherein the mechanical power calculation formula of the calculation method, such as the motor running, is shown as the formula (1):

P＝ω×T_e (1)。

in formula (1), P is the running power of the motor, omega is the given rotating speed of the motor, and T_eThe real-time torque of the motor rotor under the condition of a given rotating speed is adopted.

And 2, acquiring the maximum value of the direct-current side bus voltage of the motor vector control system by using the rotating speed control unit, inputting the maximum value into the voltage processing module, and obtaining the maximum reference voltage required for calculating the q-axis current reference value according to the q-axis current reference value minimization principle.

Specifically, according to the power equivalent principle of the speed regulating system of the permanent magnet synchronous motor, under an ideal condition without considering conditions such as friction loss, the relationship, as shown in formula (2), of the motor electric power calculation formula exists between the operating power of the permanent magnet synchronous motor and the d-q axis current and d-q axis voltage of the motor:

P＝1.5(u_di_d+u_qi_q) (2)。

ω×T_e＝1.5(u_di_d+u_qi_q) (3)。

And 3, calculating and obtaining a q-axis current reference value of the permanent magnet synchronous motor under the given rotating speed condition by using the maximum reference voltage and the power of the permanent magnet synchronous motor under the given rotating speed condition.

In particular, vector control systems for permanent magnet synchronous machines generally apply a maximum torque control strategy, i.e. i_dControl strategy is 0. Therefore, when parameter calculation is carried out in a motor rotating speed saturation dynamic module, i is applied_dAfter the strategy of 0, the mathematical relation expression of equation (3) can be further simplified, and the simplified mathematical relation expression is shown in equation (4):

ω×T_e＝1.5u_qi_q (4)。

by combining formula (1) with formula (2), using i_d0 in principleCalculating i_qA reference value.

wherein i is calculated by the formula (5)_qrefThe bus voltage is at the maximum value on the DC side (i.e., u_qIn the maximum state). From the power calculation method, when the power P of the motor is given, P ═ u_q×i_qref(i_qrefI.e. i in the formula (4)_q) Then u is_qAnd i_qrefIn inverse proportion if i is_qrefRelatively small so as not to enter the saturation region, u_qShould take a large value, so in this part of the calculation, u_qThe maximum value of the DC side bus voltage is obtained, namely no matter what power condition the motor works under, the driving voltage of the motor can not exceed the maximum value u of the DC side bus voltage_q。

U_dcI_dc＝P_dc＝P_inv≈P_motor (6)。

In formula (6), U_dcIs a DC side bus voltage, I_dcIs a direct-side bus current, P_dcIs straightPower of current side bus, P_invTo inverter power, P_motorIs the motor power. As can be seen from the expressions (4), (5) and (6), if the predetermined rotational speed is input and the q-axis current i is converted to the predetermined value_qAnd the given q-axis voltage value of the motor further converted reaches the DC side bus voltage U_dcWhen the voltage of the motor is not regulated by the control system, the motor control system is in a voltage saturation state, and the regulation capacity of the system is greatly reduced. Since the given q-axis voltage is determined by the given q-axis current i_qObtained by conversion, so that when a q-axis current i is given_qWhen the given q-axis voltage is too large, the given q-axis voltage is also too large, and when the given q-axis voltage is too large until the given q-axis voltage rises to a saturation region, a voltage saturation phenomenon occurs, so that the voltage saturation phenomenon and the rotation speed saturation phenomenon occur in the same reason. To suppress the rotation speed saturation phenomenon, i_qIs limited to the outside of the saturation region, u in formula (5)_qCan be determined as the DC side bus voltage U_dcMaximum value of (1), is noted as U_maxAt this time, since the motor power has already been determined, and u_q＝U_maxIs the maximum voltage, i thus calculated_qrefFor the minimum value of q-axis current of normal operation of the motor under the given power condition, i_qrefFor reference, a given q-axis current i may be obtained_qNot too large to enter the amplitude limit of the saturation interval.

And 4, inputting the obtained q-axis current reference value into a proportion calculation module to obtain the maximum reference current after proportion amplification.

Specifically, the q-axis current is referenced to the value i_qrefAn input proportion calculation module for carrying out proportion calculation to obtain i output by the rotating speed PI regulator_qUpper limit of amplitude limitation Ki_qref. And K is a proportionality coefficient in the proportion calculation module. The determination method of the proportionality coefficient K is different for permanent magnet synchronous motors with different models and structures. In the rotation speed saturation dynamic suppression module introduced by the method, the value of the proportionality coefficient K is 2 according to the mathematical relation of rotation speed frequency-bandwidth.

And 5, inputting the maximum reference current into a reverse rotation speed saturation suppression unit to obtain the negative minimum reference current.

Specifically, i calculated by a proportion calculation module_qUpper limit of amplitude limitation Ki_qrefInput into a reverse rotation speed saturation suppression unit to obtain i_qLower limit of amplitude limit-K_iqref。

And 6, respectively inputting the maximum reference current and the minimum reference current into the maximum amplitude limiting module and the minimum amplitude limiting module, and enabling amplitude limiting circuits in the two groups of amplitude limiting modules to take the input maximum reference current and the input minimum reference current as the upper limit and the lower limit of the amplitude limiting range. The amplitude limiting module limits the output variable of the rotating speed PI regulator to be outside a rotating speed integral saturation area, and the rotating speed integral saturation phenomenon is restrained.

Specifically, i is_qThe amplitude limit upper limit and the amplitude limit lower limit are respectively input into the maximum amplitude limit module and the minimum amplitude limit module, so that the maximum amplitude limiting circuit and the minimum amplitude limiting circuit use Ki_qrefto-Ki_qrefTo limit range operation, limit i_qOutput range of x. Limited amplitude i_qWill be input into the current loop to complete the followingAnd (5) controlling the process.

According to the control strategy, a vector control system applying the rotating speed saturation dynamic suppression module is used for driving a certain permanent magnet synchronous motor and analyzing the control effect of the permanent magnet synchronous motor, as shown in fig. 5, 6 and 7. FIG. 5 is a graph showing the effect of the rotational speed control at 1800 rpm, with a rotational speed overshoot of about 50 rpm due to integral saturation; FIG. 6 is a graph showing the effect of the rotational speed control under 2400 rpm, in which the rotational speed overshoot due to integral saturation is about 40 rpm; FIG. 7 is a graph showing the effect of the rotational speed control at 3000 rpm, with the rotational speed overshoot due to integral saturation being about 25 rpm; under different rotating speed conditions, the rotating speed overshoot caused by integral saturation is less than 60 (revolutions per minute), namely 1 Hz; and under the condition of different rotating speeds, the control system can control the motor to stably operate according to the given rotating speed within 0.2 second without the rotating speed maladjustment phenomenon caused by integral saturation.

Therefore, the vector system of the permanent magnet synchronous motor applying the rotating speed saturation dynamic suppression method can adjust the range of the given current of the q axis aiming at the given rotating speed under the condition of changing the rotating speed, and has a more obvious suppression effect on the rotating speed integral saturation phenomenon. In other words, the dynamic amplitude limiting method for the output variable of the PI regulator in the scheme of the invention sets different limiting ranges for the output variable of the PI regulator under different rotating speed conditions, so that the output variable does not enter a saturation region.

Since the processing and functions of the motor speed regulating system of this embodiment are basically corresponding to the embodiment, principle and example of the device shown in fig. 1, the description of this embodiment is not given in detail, and reference may be made to the related description in the foregoing embodiment, which is not described herein again.

Through a large number of tests, the technical scheme of the invention is adopted to calculate and process the motor power under different given rotating speed conditions, so that the output variable i of the rotating speed PI regulator_qThe upper limit and the lower limit of the amplitude are changed according to the change of the motor power under different given rotating speed conditions, so that the inhibition range of a given q-axis current saturation interval is dynamically changed along with the power when the power of the motor is changed, and the variable frequency power supply is enabled to be poweredThe machine vector control system dynamically inhibits the integral saturation phenomenon of the rotating speed under different given rotating speed conditions, and is beneficial to improving the control performance of the motor speed regulating system.

According to an embodiment of the present invention, a method for controlling a rotation speed corresponding to a motor speed regulating system is also provided, as shown in fig. 8, which is a schematic flow chart of an embodiment of the method of the present invention. The rotating speed control method can be applied to a motor speed regulation system, particularly a permanent magnet synchronous motor speed regulation system, and specifically can be arranged in a rotating speed loop in a double closed loop motor vector control system formed by the rotating speed loop and a current loop and positioned at the output end of a rotating speed PI regulator in the double closed loop motor vector control system, for example, a rotating speed saturation dynamic suppression module applying the motor rotating speed saturation dynamic suppression method is added at the output end of the rotating speed PI regulator. In the rotating speed ring, a rotating speed ring closed-loop error tracking feedback unit is matched with the rotating speed PI regulator. The rotating speed control method of the permanent magnet synchronous motor speed regulating system can comprise the following steps: step S110 and step S120.

At step S110, a motor given rotation speed is obtained in a rotation speed loop in a double closed loop motor vector control system composed of the rotation speed loop and a current loop.

In step S120, a real-time torque of the motor is determined, and a range of a limit of an output variable of a rotating speed PI regulator in a rotating speed loop is dynamically adjusted according to the real-time torque of the motor and the given rotating speed of the motor, so as to control the output variable of the rotating speed PI regulator within a safe variation range of a vector control system of a double closed-loop motor, and dynamically suppress a rotating speed saturation phenomenon generated during a motor speed-up process. By making the output variable i of a speed PI regulator_qThe upper limit and the lower limit of the amplitude are changed according to the change of the motor power under different given rotating speed conditions, so that the suppression range of a given q-axis current saturation interval is dynamically changed along with the power when the power of the motor is changed, and the amplitude limit range of an output end amplitude limit module of a rotating speed PI regulator in a permanent magnet synchronous motor vector control system can be adjusted according to the change of the rotating speed.

Alternatively, the specific process of determining the real-time torque of the motor in step S120 and dynamically adjusting the amplitude limit range of the output variable of the rotation speed PI regulator in the rotation speed loop according to the real-time torque of the motor and the given rotation speed of the motor can be seen in the following exemplary description.

Referring to the flowchart of fig. 9, a specific process of dynamically adjusting the amplitude limit range of the output variable of the PI regulator in the speed loop in step S120 is further described, where the specific process includes: step S210 to step S230.

Step S210, determining the real-time torque of the motor, and determining the given power of the motor at the given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor. For example: and the motor torque-power conversion module can detect the output torque when the motor runs. The output torque of the motor and the given rotating speed are input into the multiplier, and the given power of the motor under the given rotating speed condition can be obtained.

More optionally, the specific process of determining the real-time torque of the motor in step S210 and determining the given power of the motor at the given rotation speed of the motor according to the real-time torque of the motor and the given rotation speed of the motor may be as described in the following exemplary description.

The following further describes a specific process for determining the given power of the motor at the given rotation speed of the motor in step S210, with reference to a flowchart of an embodiment of determining the given power of the motor at the given rotation speed of the motor in the method of the present invention shown in fig. 10, and may include: step S310 and step S320.

And step S310, detecting the output torque of the motor during running as the real-time torque of the motor. For example: real-time torque T of motor rotor_eThe sampling can be obtained by a sensing module of a permanent magnet synchronous motor speed regulating system. As in the torque-power detection module, the torque detection module is used for detecting the real-time output torque T when the motor runs_e。

And step S320, taking the product of the real-time torque of the motor and the given rotating speed of the motor as the given power of the motor at the given rotating speed of the motor.

And step S220, determining a given q-axis current reference value of the motor according to the given power. For example: and the equivalent current calculation module is used for calculating the q-axis current reference value of the motor under the condition of a given rotating speed through the given power of the motor output by the motor torque-power conversion module, so that the motor can normally operate, but the equivalent current calculation module is small enough to ensure that the q-axis current reference value cannot enter a saturation region.

More alternatively, the specific process of determining the given q-axis current reference value of the motor according to the given power in step S220 can be seen in the following exemplary description.

The following further describes a specific process of determining the given q-axis current reference value of the motor in step S220, with reference to a flowchart of an embodiment of determining the given q-axis current reference value of the motor in the method of the present invention shown in fig. 11, and the specific process may include: step S410 to step S430.

And step S410, detecting the maximum value of the voltage of the direct-current side bus of the motor speed regulating system to obtain the maximum value of the voltage of the direct-current bus. For example: the rotating speed control unit is used for detecting the maximum value of the voltage of the direct-current side bus; e.g. maximum value U of DC side bus voltage_maxAnd the voltage is obtained by sampling through a voltage sampling module of the permanent magnet synchronous motor speed regulating system.

And step S420, performing reciprocal and proportion calculation processing on the maximum value of the direct-current bus voltage to obtain the reciprocal of the maximum value of the direct-current side bus voltage with the proportion coefficient. For example: and the voltage processing module performs reciprocal and proportional calculation processing on the maximum value of the detected direct-current side bus voltage so as to complete the subsequent current calculation process. The maximum value of the voltage of a direct-current side bus of the motor vector control system is obtained by the rotating speed control unit, the maximum value is input into the voltage processing module, and the maximum reference voltage required by the calculation of the q-axis current reference value is obtained according to the q-axis current reference value minimization principle. Specifically, according to the power equivalent principle of the speed regulating system of the permanent magnet synchronous motor, under an ideal condition without considering conditions such as friction loss, the relationship, as shown in formula (2), of the motor electric power calculation formula exists between the operating power of the permanent magnet synchronous motor and the d-q axis current and d-q axis voltage of the motor:

P＝1.5(u_di_d+u_qi_q) (2)。

ω×T_e＝1.5(u_di_d+u_qi_q) (3)。

And step S430, determining the product of the given power and the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient as a q-axis current reference value of the motor at the given rotating speed of the motor. For example: the multiplier multiplies the given power P of the motor output by the torque-power detection module by the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient output by the voltage processing module to obtain a q-axis current reference value i which cannot enter a saturation range under the condition of a given rotating speed_qref. And calculating to obtain a q-axis current reference value of the permanent magnet synchronous motor under the given rotating speed condition by utilizing the maximum reference voltage and the power of the permanent magnet synchronous motor under the given rotating speed condition. In particular, vector control systems for permanent magnet synchronous machines generally apply a maximum torque control strategy, i.e. i_dControl strategy is 0. Therefore, when parameter calculation is carried out in a motor rotating speed saturation dynamic module, i is applied_dAfter the strategy of 0, the mathematical relation expression of equation (3) can be further simplified, and the simplified mathematical relation expression is shown in equation (4):

ω×T_e＝1.5u_qi_q (4)。

wherein i is calculated by the formula (5)_qrefThe bus voltage is at the maximum value on the DC side (i.e., u_qIn the maximum state). According to the power calculation method, whenWhen the power P of the motor is given, P is u_q×i_qref(i_qrefI.e. i in the formula (4)_q) Then u is_qAnd i_qrefIn inverse proportion if i is_qrefRelatively small so as not to enter the saturation region, u_qShould take a large value, so in this part of the calculation, u_qThe maximum value of the DC side bus voltage is obtained, namely no matter what power condition the motor works under, the driving voltage of the motor can not exceed the maximum value u of the DC side bus voltage_q。

Given q-axis current i output by speed regulator_qObtained by a chip calculation module in the control system i_qAnd the rotation speed is a control object of the rotation speed saturation dynamic suppression module. In a permanent magnet synchronous motor driving system, factors such as circuit loss are ignored, and the motor running power is approximately equal to the inverter power, that is, the dc side bus power, as shown in formula (6):

U_dcI_dc＝P_dc＝P_inv≈P_motor (6)。

In formula (6), U_dcIs a DC side bus voltage, I_dcIs a direct-side bus current, P_dcFor the DC side bus power, P_invTo inverter power, P_motorIs the motor power. As can be seen from the expressions (4), (5) and (6), if the predetermined rotational speed is input and the q-axis current i is converted to the predetermined value_qAnd the given q-axis voltage value of the motor further converted reaches the DC side bus voltage U_dcWhen the voltage of the motor is not regulated by the control system, the motor control system is in a voltage saturation state, and the regulation capacity of the system is greatly reduced. Since the given q-axis voltage is determined by the given q-axis current i_qObtained by conversion, so that when a q-axis current i is given_qAll-grass of Chinese character ' xing ' and ' erWhen the given q-axis voltage is too large, the given q-axis voltage is also too large, and when the given q-axis voltage is too large until the given q-axis voltage rises to a saturation region, a voltage saturation phenomenon occurs, so that the voltage saturation phenomenon and the rotation speed saturation phenomenon occur in the same manner. To suppress the rotation speed saturation phenomenon, i_qIs limited to the outside of the saturation region, u in formula (5)_qCan be determined as the DC side bus voltage U_dcMaximum value of (1), is noted as U_maxAt this time, since the motor power has already been determined, and u_q＝U_maxIs the maximum voltage, i thus calculated_qrefFor the minimum value of q-axis current of normal operation of the motor under the given power condition, i_qrefFor reference, a given q-axis current i may be obtained_qNot too large to enter the amplitude limit of the saturation interval.

For example: when the given power of the motor is determined, the given q-axis current reference value and the given q-axis voltage are in inverse proportion, in order to enable the given q-axis current reference value not to exceed a limit range, the calculated value of the given q-axis voltage is determined according to the maximum value in a reasonable interval, and the maximum value of the direct-current side bus voltage of the control system or the maximum value of the rated driving voltage of the motor can be used as the given q-axis voltage to calculate the given q-axis current reference value of the motor. Thus, the q-axis current reference value which can enable the motor to normally operate under the current given rotating speed condition but is small enough to ensure that the q-axis current reference value cannot enter a saturation region is used.

And step S230, taking the given q-axis current reference value as a reference, determining the upper limit of the amplitude limit range and the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator, so as to limit the dynamic change range of the output variable of the rotating speed PI regulator within the dynamically changed amplitude limit range. The dynamic amplitude limiting module is composed of a maximum amplitude limiting module and a minimum amplitude limiting module. The dynamic amplitude limiting module is configured at the output end of the rotating speed PI regulator and used for limiting the amplitude of the output variable of the rotating speed PI regulator. By adopting a dynamic amplitude suppression mode, the problem that the output variable tracking of the rotating speed PI regulator is inaccurate when the motor runs at high power and is generated by an amplitude limiting module with a fixed threshold value can be solved; and, the low-power operation of the motor can be improved, and the specific i_qThe amplitude limiting module cannot perform amplitude limiting operation.

For example: given motor q-axis current i to output variable of rotating speed loop PI regulator in double closed loop type vector control system_qLimiting the upper limit and the lower limit of the amplitude to prevent the upper limit and the lower limit of the amplitude from being excessively large in the positive direction or excessively small in the negative direction to cause i_qAnd when the motor enters a saturation interval, the integral saturation phenomenon of the output variable of the rotating speed PI regulator in the permanent magnet synchronous motor vector control system is inhibited. If the motor power under the given rotating speed condition can be obtained by calculating through sampling the real-time torque of the permanent magnet synchronous motor rotor and the maximum value of the direct-current side bus voltage, and then the q-axis voltage reference value corresponding to the given rotating speed is obtained by further calculating; determining the upper limit and the lower limit of the amplitude limiting module of the rotating speed PI regulator by using the given q-axis voltage reference valueAnd the lower limit limits the given q-axis current output by the rotating speed PI regulator to be outside a rotating speed integral saturation region, so that the generation of a rotating speed saturation phenomenon is inhibited.

More alternatively, the specific process of determining the upper limit of the amplitude limit range and the lower limit of the amplitude limit range of the output variable of the rotation speed PI regulator based on the given q-axis current reference value in step S230 may be as follows for exemplary explanation.

The following further describes, with reference to a flowchart of an embodiment of determining an upper limit of the amplitude limiting range and a lower limit of the amplitude limiting range of the output variable of the rotational speed PI regulator in the method of the present invention shown in fig. 12, a specific process of determining the upper limit of the amplitude limiting range and the lower limit of the amplitude limiting range of the output variable of the rotational speed PI regulator in step S230, which may include: step S510 to step S540.

Step S510, multiplying the given q-axis current reference value by a set scaling factor to obtain a product of the given q-axis current reference value and the set scaling factor. For example: the proportion calculation module is used for calculating a q-axis current reference value i_qrefAmplified to Ki by a proportionality factor K_qrefAnd the proportionality coefficient K is set according to actual motor parameters and system control requirements. And inputting the obtained q-axis current reference value into a proportion calculation module to obtain the maximum reference current after proportion amplification. Specifically, the q-axis current is referenced to the value i_qrefAn input proportion calculation module for carrying out proportion calculation to obtain i output by the rotating speed PI regulator_qUpper limit of amplitude limitation Ki_qref. And K is a proportionality coefficient in the proportion calculation module. The determination method of the proportionality coefficient K is different for permanent magnet synchronous motors with different models and structures. In the rotation speed saturation dynamic suppression module introduced by the method, the value of the proportionality coefficient K is 2 according to the mathematical relation of rotation speed frequency-bandwidth.

And step S520, converting the direction of the product of the given q-axis current reference value and the set proportionality coefficient to obtain the product of the given q-axis current reference value and the set proportionality coefficient in the reverse direction. For example: the reverse rotation speed saturation suppression unit is used for limiting the current reference value Ki_qrefThe direction of (d) is switched to the negative direction. And inputting the maximum reference current into a reverse rotation speed saturation suppression unit to obtain the negative minimum reference current. Specifically, i calculated by a proportion calculation module_qUpper limit of amplitude limitation Ki_qrefInput into a reverse rotation speed saturation suppression unit to obtain i_qLower limit of amplitude limit-K_iqref。

And step S530, taking the product of the given q-axis current reference value and a set proportionality coefficient as the upper limit of the amplitude limit range of the output variable of the rotating speed PI regulator. For example: maximum amplitudeAnd the degree limiting module is used for determining and limiting the upper limit of the output variable of the rotating speed PI regulator. The amplitude limit upper limit of the maximum amplitude limit module is obtained by multiplying a given q-axis current reference value output by the equivalent current calculation module by a proportionality coefficient; when the given q-axis current reference value changes, the amplitude limit upper limit of the maximum amplitude limit module changes according to the given q-axis current reference value, so that dynamic control over the amplitude limit upper limit is realized. The maximum amplitude limiting module is a limiting circuit which uses Ki_qrefLimiting the amplitude of the output variable of the rotating speed PI regulator to be not higher than Ki as the upper limit of the amplitude_qref。

And step S540, taking the product of the inverted given q-axis current reference value and a set proportionality coefficient as the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator. For example: and the minimum amplitude limiting module is used for determining and limiting the lower limit of the output variable of the rotating speed PI regulator. The amplitude limit lower limit of the minimum amplitude limit module is obtained by multiplying a given q-axis current reference value output by the equivalent current calculation module by a proportionality coefficient and changing the current reference direction by using a reverse rotation speed saturation suppression unit, and when the given q-axis current reference value is changed, the amplitude limit lower limit of the minimum amplitude limit module is changed according to the given q-axis current reference value so as to realize the dynamic control of the amplitude limit lower limit. The minimum amplitude limiting module is a limiting circuit with-Ki_qrefLimiting the amplitude of the output variable of the rotating speed PI regulator to be not lower than-Ki for the lower limit of the amplitude_qref。

The maximum reference current and the minimum reference current are respectively input into the maximum amplitude limiting module and the minimum amplitude limiting module, and the amplitude limiting circuits in the two groups of amplitude limiting modules use the input maximum reference current and the input minimum reference current as the upper limit and the lower limit of the amplitude limiting range. The amplitude limiting module limits the output variable of the rotating speed PI regulator to be outside a rotating speed integral saturation area, and the rotating speed integral saturation phenomenon is restrained. Specifically, i is_qThe amplitude limit upper limit and the amplitude limit lower limit are respectively input into the maximum amplitude limit module and the minimum amplitude limit module, so that the maximum amplitude limiting circuit and the minimum amplitude limiting circuit use Ki_qrefto-Ki_qrefTo limit range operation, limit i_qOutput range of x. Limited amplitude i_qWill be input into the current loop to complete the subsequent control process.

In an alternative embodiment, the method may further include: and under the condition of dynamically inhibiting the rotating speed saturation phenomenon generated in the motor speed increasing process, the current PI regulator in the current loop is dynamically inhibited from outputting a given q-axis voltage amplitude.

For example: the adopted dynamic amplitude suppression method outputs variable i to the rotating speed ring_qAmplitude limiting is carried out to prevent the rotation speed from entering a saturation interval, and a variable i is output by a rotation speed ring_qThe upper limit and the lower limit of the variation amplitude are obtained by calculating and processing the maximum value of the motor power and the voltage of the direct-current side busThe control mode can ensure that the subsequent d-q axis output voltage is not higher than the maximum value of the direct current side bus voltage to generate a voltage saturation phenomenon, and the problem of the motor d-q axis voltage saturation phenomenon caused by errors generated by the rotation speed integral saturation phenomenon in a permanent magnet synchronous motor vector control system is solved. Under the condition of a given rotating speed of the motor, a given q-axis current output by the rotating speed PI regulator is processed by the dynamic amplitude limiting module and then is input into the current loop as an input variable of the current loop to execute a subsequent control process. The input variable of the q-axis current loop PI regulator is a given q-axis current i subjected to dynamic saturation suppression_qAnd the actual q-axis current i_qGiven a q-axis current i_qIs based on the DC bus voltage reaching a maximum value, and i_dThe control strategy of 0 is amplitude-limited, so that the output variable q of the q-axis current loop PI regulator is set to a predetermined voltage U_qThe amplitude of the signal is also restrained to a certain degree, U_qThe amplitude of the signal will not exceed the maximum value of the voltage of the direct current side bus and enter a voltage saturation state. For this reason, a voltage amplitude limiting module, which is provided at the output terminal of the current loop PI regulator and controls the given d-q axis voltage value output by the PI regulator not to enter the saturation region, may be eliminated, so that the structure of the controllable system is simplified and the control performance is improved.

Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the motor speed regulating system, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

Through a large number of tests, the technical scheme of the embodiment is adopted, and the method passesTo the output variable i of the rotating speed ring_qAmplitude limiting is carried out to prevent the rotation speed from entering a saturation interval, and a variable i is output by a rotation speed ring_qThe upper limit and the lower limit of the variation amplitude are obtained by calculating and processing the maximum value of the motor power and the maximum value of the direct-current side bus voltage, so that the subsequent d-q axis output voltage can be ensured not to be higher than the maximum value of the direct-current side bus voltage to generate a voltage saturation phenomenon, and the problem of the motor d-q axis voltage saturation phenomenon caused by errors generated by the rotation speed integral saturation phenomenon in a vector control system of the permanent magnet synchronous motor can be solved; therefore, a voltage amplitude limiting module which is configured at the output end of the current loop PI regulator and used for controlling the given d-q axis voltage value output by the PI regulator not to enter a saturation region can be eliminated, and the control process is simplified.

According to an embodiment of the present invention, there is also provided a storage medium corresponding to the rotational speed control method, the storage medium including a stored program, wherein the apparatus in which the storage medium is located is controlled to execute the rotational speed control method described above when the program is executed.

Since the processing and functions implemented by the storage medium of this embodiment substantially correspond to the embodiments, principles, and examples of the methods shown in fig. 8 to fig. 12, details are not described in the description of this embodiment, and reference may be made to the related descriptions in the foregoing embodiments, which are not described herein again.

According to an embodiment of the present invention, there is also provided a processor corresponding to the rotational speed control method, the processor being configured to run a program, wherein the program is configured to execute the rotational speed control method described above when running.

Since the processing and functions implemented by the processor of this embodiment substantially correspond to the embodiments, principles and examples of the methods shown in fig. 8 to 12, the description of this embodiment is not detailed, and reference may be made to the related descriptions in the foregoing embodiments, which are not described herein again.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A rotational speed control method characterized by comprising:

acquiring a given rotating speed of a motor in a rotating speed loop in a double closed loop motor vector control system consisting of the rotating speed loop and a current loop;

determining the real-time torque of a motor, and dynamically adjusting the amplitude limit range of an output variable of a rotating speed PI regulator in a rotating speed loop according to the real-time torque of the motor and the given rotating speed of the motor so as to dynamically inhibit the rotating speed saturation phenomenon generated in the speed increasing process of the motor; the method comprises the following steps of determining the real-time torque of a motor, and dynamically adjusting the amplitude limit range of the output variable of a rotating speed PI regulator in a rotating speed loop according to the real-time torque of the motor and the given rotating speed of the motor, wherein the method comprises the following steps:

determining real-time torque of a motor, and determining given power of the motor at a given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor;

determining a given q-axis current reference value of the motor according to the given power;

and determining the upper limit and the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference.

2. The rotational speed control method according to claim 1,

determining the real-time torque of the motor, and determining the given power of the motor at the given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor, wherein the determining comprises the following steps:

detecting output torque of a motor during operation as real-time torque of the motor;

and taking the product of the real-time torque of the motor and the given rotating speed of the motor as the given power of the motor at the given rotating speed of the motor.

3. A method of controlling rotational speed as defined in claim 1, wherein determining a given q-axis current reference value for the electric machine based on the given power comprises:

detecting the maximum value of the voltage of a direct-current side bus of a motor speed regulating system to obtain the maximum value of the voltage of the direct-current bus;

performing reciprocal and proportional calculation processing on the maximum value of the direct-current bus voltage to obtain the reciprocal of the maximum value of the direct-current side bus voltage with a proportional coefficient;

and determining the product of the given power and the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient as a q-axis current reference value of the motor at the given rotating speed of the motor.

4. The rotational speed control method according to claim 1,

and determining the upper limit and the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference, wherein the method comprises the following steps:

multiplying the given q-axis current reference value by a set proportionality coefficient to obtain a product of the given q-axis current reference value and the set proportionality coefficient;

converting the direction of the product of the given q-axis current reference value and a set proportionality coefficient to obtain the product of the given q-axis current reference value and the set proportionality coefficient in the reverse direction;

taking the product of the given q-axis current reference value and a set proportionality coefficient as the upper limit of the amplitude limit range of the output variable of the rotating speed PI regulator;

and taking the product of the inverted given q-axis current reference value and a set proportionality coefficient as the lower limit of the amplitude limit range of the output variable of the rotating speed PI regulator.

5. The rotational speed control method according to any one of claims 1 to 4, characterized by further comprising: and under the condition of dynamically inhibiting the rotating speed saturation phenomenon generated in the motor speed increasing process, the current PI regulator in the current loop is dynamically inhibited from outputting a given q-axis voltage amplitude.

6. A rotational speed control apparatus, characterized by comprising: an acquisition unit and a rotational speed saturation suppression unit; wherein the content of the first and second substances,

the acquisition unit is used for acquiring the given rotating speed of the motor in a rotating speed loop in a double closed loop motor vector control system consisting of the rotating speed loop and a current loop;

the rotating speed saturation suppression unit is used for determining the real-time torque of the motor, and dynamically adjusting the amplitude limit range of the output variable of the rotating speed PI regulator in the rotating speed loop according to the real-time torque of the motor and the given rotating speed of the motor so as to dynamically suppress the rotating speed saturation phenomenon generated in the speed increasing process of the motor; wherein the rotation speed saturation suppression unit includes: the device comprises a power determining module, a current determining module and an amplitude limiting module;

the rotating speed saturation suppression unit determines the real-time torque of the motor, dynamically adjusts the amplitude limit range of the output variable of the rotating speed PI adjuster in the rotating speed ring according to the real-time torque of the motor and the given rotating speed of the motor, and comprises the following steps:

the power determination module is used for determining the real-time torque of the motor and determining the given power of the motor at the given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor;

the current determination module is used for determining a given q-axis current reference value of the motor according to the given power;

and the amplitude limiting module is used for determining the upper limit of the amplitude limiting range and the lower limit of the amplitude limiting range of the output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference.

7. The rotational speed control apparatus according to claim 6, wherein the power determination module includes: the motor torque detection module and the first multiplier;

the power determination module determines real-time torque of a motor, and determines given power of the motor at a given rotating speed of the motor according to the real-time torque of the motor and the given rotating speed of the motor, and comprises the following steps:

the motor torque detection module is used for detecting the output torque of the motor during operation as the real-time torque of the motor;

and the first multiplier is used for taking the product of the real-time torque of the motor and the given rotating speed of the motor as the given power of the motor at the given rotating speed of the motor.

8. A rotational speed control apparatus according to claim 6, wherein the current determination module comprises: the direct current bus voltage detection module, the voltage processing module and the second multiplier are connected;

the current determination module determines a given q-axis current reference value of the motor based on the given power, including:

the direct current bus voltage detection module is used for detecting the maximum value of the direct current side bus voltage of the motor speed regulating system to obtain the maximum value of the direct current bus voltage;

the voltage processing module is used for carrying out reciprocal taking and proportion calculation processing on the maximum value of the direct-current bus voltage to obtain the reciprocal of the maximum value of the direct-current side bus voltage with a proportion coefficient;

and the second multiplier is used for determining the product of the given power and the reciprocal of the maximum value of the direct-current side bus voltage with the proportionality coefficient as a q-axis current reference value of the motor at the given rotating speed of the motor.

9. A speed control apparatus according to claim 6, wherein the amplitude limiting module comprises: the device comprises a proportion calculation module, a reverse control module, a maximum amplitude limiting module and a minimum amplitude limiting module;

the amplitude limiting module determines an upper limit of an amplitude limiting range and a lower limit of the amplitude limiting range of an output variable of the rotating speed PI regulator by taking the given q-axis current reference value as a reference, and comprises the following steps:

the proportion calculation module is used for multiplying the given q-axis current reference value by a set proportion coefficient to obtain the product of the given q-axis current reference value and the set proportion coefficient;

the reverse control module is used for converting the direction of the product of the given q-axis current reference value and the set proportionality coefficient to obtain the reverse product of the given q-axis current reference value and the set proportionality coefficient;

the maximum amplitude limiting module is used for taking the product of the given q-axis current reference value and a set proportionality coefficient as the upper limit of the amplitude limiting range of the output variable of the rotating speed PI regulator;

and the minimum amplitude limiting module is used for taking the product of the inverted given q-axis current reference value and a set proportionality coefficient as the lower limit of the amplitude limiting range of the output variable of the rotating speed PI regulator.

10. The rotation speed control device according to any one of claims 6 to 9, wherein the rotation speed saturation suppression unit is further configured to dynamically suppress a given q-axis voltage amplitude output by the current PI regulator in the current loop in a case where a rotation speed saturation phenomenon generated during a motor speed increase is dynamically suppressed.

11. A motor speed regulation system, comprising: a rotation speed control apparatus as claimed in any one of claims 6 to 10.

12. A storage medium, characterized in that the storage medium includes a stored program, wherein when the program is executed, a device in which the storage medium is located is controlled to execute the rotational speed control method according to any one of claims 1 to 5.

13. A processor, characterized in that the processor is configured to run a program, wherein the program is configured to execute the rotational speed control method according to any one of claims 1 to 5 when running.