Optimization control method for duplex-winding motor and master-slave frequency converter adopted by optimization control method

Abstract

The invention relates to a double-winding motor optimizing control method and a master-slave frequency converter adopted by the double-winding motor optimizing control method, the master-slave frequency converter is a master-slave control system comprising at least two frequency converters which are connected with each other through a communication medium, and the optimizing control method comprises the following steps: the master-slave frequency converter respectively samples current and voltage of a double-winding motor; after an excitation current component is obtained through calculation, the difference between the excitation current component and a corresponding given excitation reference current component is obtained, Bessel filtering is carried out on the product of the excitation current component and a corresponding flux linkage value, finally compensation angles are obtained through adjustment of a PI adjuster, the compensation angles are correspondingly superposed to corresponding flux linkage orientation angles, and the flux linkage orientation angle is obtained. An excitation voltage instruction and a torque voltage instruction of the master-slave control system are subjected to d-q inverse transformation and 2-3 transformation of a flux linkage orientation angle respectively to generate a three-phase voltage instruction to drive the double-winding motor, so that the double-winding motor rapidly realizes stability of a coupling magnetic field during load fluctuation, and the rotating speed fluctuation range caused by sudden load change is effectively reduced; the system stability is improved.

Description

Technical Field

[0001] This invention belongs to the field of AC motor and its control technology, specifically relating to an optimization control method for a dual-winding motor and the master-slave frequency converter used therein. Background Technology

[0002] In the field of high-power AC motor drive, frequency converters are generally used to drive AC motors for speed regulation. Due to the limitations of their power rating, some high-power three-phase motors cannot be driven independently by a single frequency converter. Therefore, multiple frequency converters are used to drive a dual-winding motor of the same power at the same time, which effectively expands the power of frequency conversion drive.

[0003] Multiple frequency converters typically use a master-slave configuration to drive the same dual-winding motor. Vector control is the basic control strategy, and the master and slave frequency converters exchange data through high-speed communication media such as optical fiber. The master and slave frequency converters can drive one set of windings in the dual-winding motor respectively. Through the high-speed communication medium, they coordinate control by quickly sharing excitation current commands and torque current commands, which can achieve good control results in steady state.

[0004] Dual-winding motors require precise control of the current, phase, and frequency of two independent windings simultaneously. As the number of control variables increases, the control algorithm needs to have stronger multi-objective coordination capabilities to avoid magnetic field distortion or torque fluctuations caused by parameter adaptability.

[0005] The magnetic field coupling characteristics of a dual-winding system are more sensitive to parameter changes (such as winding resistance and inductance drift), which may cause control loop instability. The magnetic field coupling effect of each winding is more complex, and it is necessary to optimize the vector control algorithm to achieve decoupling and independent adjustment of the magnetic field of each winding. The dynamic response speed of a dual-winding system is limited by the timing control of dual-winding parameter matching and magnetic field switching. If the adjustment is not proper, it can easily cause speed fluctuations.

[0006] Dual-winding motors require the output current to be distributed equally between the two frequency converters. If the current difference between the two windings is too large, it can easily lead to overload of the power devices of the frequency converter or abnormal local temperature rise.

[0007] In this situation, if the master and slave frequency converters in the frequency conversion system each use their own vector control strategies, the magnetic field coupling oscillation between the motor windings will occur due to the difference in electrical parameters between the two sets of windings of the dual-winding motor. This will cause fluctuations in the current of each phase of the motor, which will cause the drive devices of the frequency converter to bear excessive electrical stress, endangering operational safety and equipment life. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide an optimal control method for a dual-winding motor and the master-slave frequency converter used therein. The method of this invention can effectively suppress the coupling oscillation of the magnetic field of the dual-winding motor caused by load fluctuations, and is a control method that can maintain the stability of the magnetic field of the dual-winding motor under load fluctuations.

[0009] This invention is implemented as follows: a method for optimal control of a dual-winding motor and a master-slave frequency converter used therein. The specific steps of the optimal control method are as follows: S1: The master and slave frequency converters sample the current and voltage of the two windings of the dual-winding motor, respectively, and calculate the excitation current component through the flux linkage observer. The specific process is as follows: The master and slave frequency converters respectively sample the three-phase voltage and current signals of one set of windings in a dual-winding motor, and the flux linkage observer calculates the first flux linkage orientation angle θ1, the second flux linkage orientation angle θ2, and the first flux linkage value. 1 and second magnetic flux value 2. The current signal is a three-phase current signal, which, after 3-2 transformation and dq transformation, yields the first torque current component I. qs1 Second torque current component I qs2 and the first excitation current component I ds1 With the second excitation current component I ds2 .

[0010] The 3-2 transformation converts the stationary three-phase current into a stationary two-phase current in the αβ coordinate system, and the dq transformation converts the stationary two-phase current in the αβ coordinate system into a rotating two-phase current in the dq coordinate system, thereby obtaining the torque current component and the excitation current component, respectively.

[0011] S2: The difference between the excitation current components of the two windings in step S1 and the corresponding given excitation reference current components is then multiplied by the corresponding flux linkage values ​​and filtered. Finally, the compensation angle is obtained after adjustment by the regulator. Specifically, this involves: [the first excitation current component I] ds1 With the second excitation current component I ds2 Respectively compared with the system excitation reference current components I dsRef Perform a difference operation, and then compare the differenced value with the corresponding first flux linkage value. 1、 Second magnetic flux value The product is multiplied by 2, and the result is filtered by Bessel to obtain the first filtered excitation current component I. ds1_KFilt With the second filter excitation current component I ds2_Kfilt The first compensation angle is obtained after adjusting each of the individual PI controllers. θ1 and the second compensation angle θ2.

[0012] S3: The compensation angles obtained in step S2 are superimposed on the flux linkage orientation angles of the master and slave frequency converters respectively before driving the output. Specifically, the first excitation voltage command V is calculated and obtained through the control algorithm of the master and slave frequency converters. d1ref With the second excitation voltage command V d2ref First torque voltage command V q1ref With the second torque voltage command V q2ref The main inverter's flux linkage orientation angle adopts θ1+ The value of θ1 is used as the orientation angle, and the orientation angle of the inverter flux linkage is taken as θ2+. The value of θ2 is used as the orientation angle, and the first excitation voltage command V d1ref First torque voltage command V q1ref and the second excitation voltage command V d2ref Second torque voltage command V q2ref The corresponding magnetic flux orientation angle is combined to perform dq inverse transformation and 2-3 transformation, respectively, and then used as the reference voltage output.

[0013] The inverse dq transformation converts the DC voltage component in the synchronous rotating coordinate system dq into the AC voltage component in the two-phase stationary coordinate system αβ. The 2-3 transformation converts the AC voltage component in the two-phase stationary coordinate system αβ into the three-phase AC voltage component in the three-phase stationary coordinate system.

[0014] Furthermore, the magnetic flux observer uses either stator flux orientation or rotor flux orientation for its magnetic field orientation.

[0015] Furthermore, the control algorithm of the master-slave frequency converter adopts a vector control algorithm, including a sensorless vector control algorithm and a speed sensor-equipped vector control algorithm.

[0016] The dual-winding motors include dual-winding asynchronous motors, dual-winding permanent magnet synchronous motors, and dual-winding excitation synchronous motors.

[0017] The dual-winding motor optimization control method employs a master-slave frequency converter system comprising at least two frequency converters interconnected via a communication medium. This system has at least one three-phase output channel and is equipped with a digital chip serving as the carrier of the control algorithm. The communication medium is optical fiber.

[0018] Furthermore, the master-slave frequency converter achieves power conversion through power electronic devices such as MOSFETs, IGBTs, and IGCTs.

[0019] The beneficial effects of this invention are as follows: The method of this invention uses Bessel filtering to process the excitation current component, realizing optimal control of the dual-winding motor. The compensation control method of this invention can effectively suppress the magnetic field coupling oscillation of the dual-winding motor under load fluctuations, and will not generate control disturbances during the steady-speed drive of the system. This enables the dual-winding motor to quickly stabilize the coupled magnetic field under load fluctuations, solving the problem of control loop instability caused by the magnetic field coupling characteristics of the dual-winding motor being more sensitive to parameter changes. It can effectively reduce the fluctuation range of the speed of the dual-winding motor caused by sudden load changes, improve the stability of the system, and can be applied to high-power dual-winding motor drive applications such as oil and gas transmission, ship propulsion, and wind tunnels. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the optimization control method described in this invention.

[0021] Figure 2 This is a schematic diagram illustrating the process and principle of vector control of a dual-winding motor by obtaining the compensation angle in the master-slave control system described in this invention.

[0022] In the diagram: 1. Block diagram of the vector control principle of the main frequency converter for the first winding of the motor; 2. Block diagram of vector control principle for the second winding of the motor from the frequency converter; 3. First winding; 4. Second winding; 11. Calculation method for obtaining the compensation angle of the first winding and the location for implementing the compensation angle; 21. Calculation method for obtaining the compensation angle of the second winding and the location for implementing the compensation angle. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] According to the appendix Figure 1 and attached Figure 2This invention discloses an optimal control method for a dual-winding motor and the master-slave frequency converter used therein. The master-slave frequency converter is a master-slave control system comprising at least two frequency converters. The frequency converters are interconnected via a communication medium, preferably optical fiber. The master-slave frequency converter converts electrical energy using power electronic devices such as MOSFETs, IGBTs, and IGCTs, and has at least one three-phase output channel. It also uses a digital chip as the carrier of the control algorithm for the master-slave control system. The control algorithm of the master-slave control system employs a vector control algorithm, including sensorless vector control and sensor-based vector control algorithms. This embodiment uses two frequency converters.

[0025] The specific steps of the optimization control method are as follows: S1. The master and slave frequency converters sample the current and voltage of the dual-winding motor and calculate the excitation current component.

[0026] Reference Figure 2 The schematic diagram illustrates the process and principle of the master-slave control system for vector control of a dual-winding motor by obtaining the compensation angle. This embodiment includes a schematic diagram of the main frequency converter performing vector control on the first winding of the motor. Figure 1 The principle of vector control of the second winding of the motor by the frequency converter Figure 2 The master and slave frequency converters respectively sample the three-phase voltage and current signals of one winding in a dual-winding motor, where the three-phase voltages of the first winding 3 are: v a1 v b1 and v c1 The three-phase voltages of the second winding 4 are as follows: v a2 v b2 and v c2 The current signal can be acquired by collecting only two phase currents, which are: I a1 I c1 I a2 and I c2 The third phase current can be passed through I a +I b +I c The first flux orientation angle θ1, the second flux orientation angle θ2, and the first flux value were obtained by calculation using the formula = 0 and the flux observation device. 1 and second magnetic flux value 2. The current signal is a three-phase current signal, which, after 3-2 transformation and dq transformation, yields the first torque current component I. qs1 Second torque current component I qs2 and the first excitation current component I ds1 With the second excitation current component I ds2The magnetic flux observer described above uses either stator flux orientation or rotor flux orientation for its magnetic field orientation.

[0027] The 3-2 transformation converts the stationary three-phase current into a stationary two-phase current in the αβ coordinate system, and the dq transformation converts the stationary two-phase current in the αβ coordinate system into a rotating two-phase current in the dq coordinate system, thereby obtaining the torque current component and the excitation current component, respectively.

[0028] S2. The excitation current components of the two windings in step S1 are differentiated from the corresponding given reference excitation current components, and then the products of the two components with the corresponding flux linkage values ​​are filtered. Finally, the compensation angle is obtained after adjustment by the regulator.

[0029] Reference Figure 1 As shown, the first excitation current component I ds1 With the second excitation current component I ds 2. The excitation current reference value I output by the system flux linkage regulator is compared with the reference value I. dsRef Perform a difference operation, and then compare the differenced value with the corresponding first flux linkage value. 1、 Second magnetic flux value The product is multiplied by 2, and the result is filtered by Bessel to obtain the first filtered excitation current component I. ds1_KFilt With the second filter excitation current component I ds2_Kfilt Then, each is adjusted by its own PI controller. The output signal of the PI controller is used as the angle offset and is superimposed on the orientation angle signals of the two magnetic flux linkages to obtain the first compensation angle. θ1 and the second compensation angle θ2.

[0030] S3. The compensation angles obtained in step S2 are superimposed on the flux linkage orientation angles of the master and slave frequency converters respectively, and then the drive output is performed. Reference Figure 2 As shown, the first excitation voltage command is calculated and obtained through the vector control algorithm of the master-slave control system. V d1ref With the second excitation voltage command V d2ref First torque voltage command V q1ref With the second torque voltage command V q2ref . Reference Figure 2 As shown, the flux linkage orientation angle of the main frequency converter is θ1+ The value of θ1 is used as the orientation angle, and it is applied to the calculation method of the compensation angle of the first winding and the compensation angle implementation position 11. The orientation angle of the inverter flux linkage is θ2+ The value of θ2 is used as the orientation angle, and the calculation method for the compensation angle of the second winding and the compensation angle implementation position 21 are applied. The first excitation voltage command V d1ref First torque voltage command V q1ref and the second excitation voltage command V d2ref Second torque voltage command V q2ref The reference voltage is obtained by performing inverse dq transformation and 2-3 transformation respectively, based on the corresponding magnetic flux orientation angle. U a1Ref U b1Ref U c1Ref U a2Ref U b2Ref and U c2Ref Output. Figure 2 middle The system flux linkage value is set as a reference, typically via a menu setting, ω. The system speed is given by ω, used for motor speed regulation. This is typically adjusted in real-time by the user via a menu. ω represents the real-time motor speed, which can be obtained from a speed sensor. dsRef I is the excitation current setpoint output by the system flux linkage regulator. qsRef This is the setpoint for the torque current output by the system speed regulator.

[0031] The difference between the excitation current component and the corresponding given reference excitation current component is multiplied by the flux linkage value observed by the flux linkage observer of each winding. The oscillating component in the magnetic field is converted into a real-time flux linkage fluctuation. After Bessel filtering, the corresponding fluctuation amplitude is analyzed and used as an angle difference compensation in the space vector angle of the three-phase voltage to be output in the next step. This pre-compensates for the magnetic field oscillation component, realizing the magnetic field decoupling control of the dual-winding motor and ultimately effectively suppressing magnetic field oscillation. In the final steady state, the first compensation angle in the method of this invention... θ1 and the second compensation angle θ2 is a constant value, representing the difference in flux linkage angle caused by the difference in winding characteristic parameters in a dual-winding motor.

[0032] The inverse dq transformation converts the DC voltage component in the synchronous rotating coordinate system dq into the AC voltage component in the two-phase stationary coordinate system αβ. The 2-3 transformation converts the AC voltage component in the two-phase stationary coordinate system αβ into the three-phase AC voltage component in the three-phase stationary coordinate system.

[0033] The dual-winding motor described in this invention includes a dual-winding asynchronous motor, a dual-winding permanent magnet synchronous motor, and a dual-winding excitation synchronous motor.

[0034] The specific embodiments described in this invention are merely illustrative examples of the principles of this invention and are only intended to illustrate the principles and effects of this invention. For those skilled in the art, various modifications, improvements, equivalents, or substitutions can be made without departing from the inventive concept of this invention, and these should all fall within the protection scope of this invention. The scope of protection claimed by this invention is defined by the claims of this invention.

Claims

1. A method for optimal control of a dual-winding motor, characterized in that... The specific steps of the optimization control method are as follows: S1: The master and slave frequency converters sample the current and voltage of the two windings of the dual-winding motor, respectively, and calculate the excitation current component through the flux linkage observer. S2: The difference between the excitation current components of the two windings in step S1 and the corresponding given excitation reference current components is then multiplied by the corresponding flux linkage values ​​and filtered. Finally, the compensation angle is obtained after adjustment by the regulator. Specifically, this involves: [the first excitation current component I] ds1 With the second excitation current component I ds2 Respectively compared with the system excitation reference current components I dsRef Perform a difference operation, and then compare the differenced value with the corresponding first flux linkage value. 1、 Second magnetic flux value The product is multiplied by 2, and the result is filtered by Bessel to obtain the first filtered excitation current component I. ds1_KFilt With the second filter excitation current component I ds2_Kfilt The first compensation angle is obtained after adjusting each of the individual PI controllers. θ1 and the second compensation angle θ2, S3: The compensation angles obtained in step S2 are superimposed on the flux linkage orientation angles of the master and slave frequency converters respectively before driving the output. Specifically, the first excitation voltage command V is calculated and obtained through the control algorithm of the master and slave frequency converters. d1ref With the second excitation voltage command V d2ref First torque voltage command V q1ref With the second torque voltage command V q2ref The main inverter's flux linkage orientation angle adopts θ1+ The value of θ1 is used as the orientation angle, and the orientation angle of the inverter flux linkage is taken as θ2+. The value of θ2 is used as the orientation angle, and the first excitation voltage command V d1ref First torque voltage command V q1ref and the second excitation voltage command V d2ref Second torque voltage command V q2ref The corresponding magnetic flux orientation angle is combined to perform dq inverse transformation and 2-3 transformation, respectively, and then used as the reference voltage output.

2. The optimization control method for a dual-winding motor according to claim 1, characterized in that... The specific process of step S1 is as follows: the master and slave frequency converters respectively sample the three-phase voltage and current signals of one set of windings in the dual-winding motor, and the flux linkage observer calculates the first flux linkage orientation angle θ1, the second flux linkage orientation angle θ2, and the first flux linkage value. 1 and second magnetic flux value 2. The current signal is a three-phase current signal, which, after 3-2 transformation and dq transformation, yields the first torque current component I. qs1 Second torque current component I qs2 and the first excitation current component I ds1 With the second excitation current component I ds2 .

3. The optimization control method for a dual-winding motor according to claim 1, characterized in that: The magnetic flux observer uses either stator flux orientation or rotor flux orientation for its magnetic field orientation.

4. The optimization control method for a dual-winding motor according to claim 1, characterized in that: The control algorithm of the master-slave frequency converter adopts a vector control algorithm, including a sensorless vector control algorithm and a sensor-equipped vector control algorithm.

5. The optimization control method for a dual-winding motor according to claim 1, characterized in that: The inverse dq transformation converts the DC voltage component in the synchronous rotating coordinate system dq into the AC voltage component in the two-phase stationary coordinate system αβ. The 2-3 transformation converts the AC voltage component in the two-phase stationary coordinate system αβ into the three-phase AC voltage component in the three-phase stationary coordinate system.

6. The optimization control method for a dual-winding motor according to claim 2, characterized in that: The 3-2 transformation converts the stationary three-phase current into a stationary two-phase current in the αβ coordinate system, and the dq transformation converts the stationary two-phase current in the αβ coordinate system into a rotating two-phase current in the dq coordinate system, thereby obtaining the torque current component and the excitation current component, respectively.

7. The optimization control method for a dual-winding motor according to claim 1, characterized in that: The dual-winding motors include dual-winding asynchronous motors, dual-winding permanent magnet synchronous motors, and dual-winding excitation synchronous motors.

8. A master-slave frequency converter, used in the dual-winding motor optimization control method as described in any one of claims 1-7, characterized in that: The master-slave frequency converter is a master-slave control system consisting of at least two frequency converters interconnected by a communication medium, has at least one three-phase output channel, and is equipped with a digital chip as the carrier of the control algorithm.

9. The master-slave frequency converter according to claim 8, characterized in that: The master-slave frequency converter achieves power conversion through MOSFET, IGBT, and IGCT power electronic devices.

10. The master-slave frequency converter according to claim 8, characterized in that: The communication medium used is optical fiber.

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