Dual permanent magnet synchronous motor same-speed same-phase control system and control method thereof

Abstract

The invention provides a same-speed and same-phase control system for double permanent magnet synchronous motors and a control method of the same-speed and same-phase control system, and belongs to the technical field of multi-motor synchronous control. The double permanent magnet synchronous motor same-speed same-phase control system is composed of two single-motor double-closed-loop vector control systems and a synchronous controller in a cross coupling structure mode, each single-motor double-closed-loop vector control system comprises a motor, a rotating speed outer ring and a current inner ring, and a rotating speed regulator and a current regulator are PI controllers; an encoder is installed on the motor, and the encoder obtains an actual electrical angle and an actual rotating speed value output in the operation process of the motor; and the synchronous controller is used for calculating a rotating speed compensation value based on a phase angle synchronization error between the two motors and respectively outputting the rotating speed compensation value to the rotating speed regulators in the two single-motor double-closed-loop vector control systems for positive and negative feedback compensation. The tracking synchronization of the speed and the position of the double motors is still kept under the condition of load change, and the synchronization performance of the double-motor control system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-motor synchronous control, and in particular to a dual permanent magnet synchronous motor same-speed and same-phase control system and a control method thereof. Background Art

[0002] With the continuous development of the manufacturing industry, the requirements for gear strength, hardness, wear resistance and transmission noise are constantly increasing, and traditional soft tooth surfaces can no longer meet the requirements. High-quality precision hardened gears have the advantages of reducing equipment weight, miniaturizing gear transmission systems, improving machine load-bearing capacity, and reducing transmission noise. They are now widely used in the automotive, aerospace, machine tool, instrumentation and other industries. Compared with grinding, honing can not only be used to finish the tooth surface, improve and correct the processing error and tooth surface texture of the tooth surface, but also achieve high efficiency and large excess removal. It has become a finishing process for hardened gears after quenching to replace grinding.

[0003] During the honing process, the honing wheel and the workpiece gear to be honed must maintain a strict meshing relationship. The two helical gears, which are similar to a pair of spatially staggered axes, are meshed without side clearance. The material on the workpiece tooth surface is removed through the relative sliding speed at the contact point between the protruding abrasive particles of the honing wheel and the tooth surface. The honing accuracy depends not only on the contour accuracy of the tool motion trajectory, but is also directly affected by the synchronization accuracy between the honing wheel and the workpiece gear motion.

[0004] However, the existing dual-motor synchronous control technology usually only focuses on single phase synchronization or speed synchronization. In gear honing, traditional dual-motor drive systems often find it difficult to simultaneously achieve precise synchronization of speed and phase between the honing wheel and the workpiece gear. When the motor speed is not synchronized, the meshing speed and relative friction speed between the honing wheel and the workpiece gear will fluctuate, resulting in uneven contact between the abrasive particles and the tooth surface, thereby causing tooth knocking; when the motor phase is not synchronized, the meshing angle and relative position of the honing wheel and the workpiece gear will shift, resulting in unstable gear meshing or excessive wear.

[0005] In summary, the asynchronous speed and phase will lead to the gradual accumulation of machining errors, which will seriously affect the geometric accuracy of the gears. These synchronization problems not only reduce the quality of the tooth surface, but also may lead to reduced efficiency and increased operating noise of the gear transmission system, thus significantly weakening the overall performance and long-term reliability of the gear transmission system. Summary of the invention

[0006] In view of this, the present invention provides a dual permanent magnet synchronous motor same-speed and same-phase control system and a control method thereof, which adopts a PI control algorithm and a cross-coupling control structure, and optimizes the angle error to obtain a speed compensation value, thereby ensuring that the dual motors can still maintain speed and phase tracking synchronization under load changes, and keep the honing wheel and the workpiece gear in a stable meshing relationship, thereby improving the honing processing accuracy and tooth surface quality.

[0007] The technical solution adopted by the embodiment of the present invention to solve the technical problem is:

[0008] A dual permanent magnet synchronous motor same speed and same phase control system is composed of two single motor double closed loop vector control systems and a synchronous controller in a cross-coupling structure, wherein:

[0009] The single-motor dual-closed-loop vector control system includes a motor and speed outer loop and a current inner loop, wherein the speed regulator ASR and the current regulator ACR are both PI controllers; an encoder is installed on the motor, and the encoder obtains the actual electrical angle and actual speed value output during the operation of the motor;

[0010] The synchronous controller is used to calculate the speed compensation value based on the phase angle synchronization error between the two motors and output it to the speed regulators ASR in the two single-motor dual closed-loop vector control systems for positive and negative feedback compensation.

[0011] Preferably, in the single-motor dual closed-loop vector control system:

[0012] Let the system input be a given speed n * , n * Deviation n from the actual speed value n * -nAfter passing through the speed loop PI regulator, the output q-axis stator current component given value i q * ;i q * Compared with the actual value of the q-axis current component i q The deviation value i q * -i q After passing through the q-axis current PI regulator, the given voltage Uq of the q-axis component is output * ; d-axis stator current component given value i d * (i d * =0) compared to the deviation value i of the actual value id of the d-axis stator current component d * -i d After passing through the d-axis current PI regulator, the output d-axis stator voltage component is the given value U d* ;

[0013] U q * with U d * After the inverse Park transformation, the given value U of the stator voltage on the α and β axes is obtained. α * , U β * ; U α * , U β * After SVPWM modulation, a PWM signal is obtained; the PWM signal is input into the inverter to control the on and off of the thyristor in the inverter to control the operation of the motor;

[0014] The inverter outputs a three-phase current signal i to the motor A 、i B 、i C After Clarke transformation and Park transformation, the output current i d 、i q ;

[0015] The encoder obtains the actual electrical angle θ e The actual speed value n is transmitted to the Park converter and the inverse Park converter, and the actual speed value n is output to the speed loop PI regulator for deviation calculation.

[0016] Preferably, the inputs of the two single-motor dual-closed-loop vector control systems are both given speeds n ref , the expression for the phase angle synchronization error Δθ between the two motors is defined as:

[0017] θ e1 =θ 1 *p n (1)

[0018] θ e2 =θ 2 *p n (2)

[0019]

[0020] Among them, θ e1 ,θ e2 are the actual electrical angles of the first motor and the second motor respectively, p n is the pole pair number; θ 1 ,θ 2 are the actual mechanical angles of the first motor and the second motor respectively, To use the mod function to convert θ 1 ,θ2 The result of calculating the modulus of 2ρ and then converting the angle unit;

[0021] The synchronous controller includes an angle error conversion module and a cross-coupled PI controller;

[0022] The angle error conversion module is used to convert the input Δθ into a synchronous compensation value Δθ of (-180°, 180°) using a determination algorithm. comp , Δθ comp The conversion expression is:

[0023]

[0024] The synchronous compensation value Δθ comp The cross-coupled PI controller is input, and the cross-coupled PI controller outputs a speed compensation value Δe which is fed back to the speed loop PI regulators in the two single-motor dual closed-loop vector control systems, wherein negative feedback is performed on the speed PI regulator of the first motor, and positive feedback is performed on the speed PI regulator of the second motor.

[0025] Preferably, during the startup phase of the dual permanent magnet synchronous motor same-speed and same-phase control system:

[0026] If there is an initial phase difference between the two motors, that is, Δθ≠0, after starting, the two motors run smoothly and the actual speed reaches the given value n ref The synchronous controller is started at this time; the system makes the speeds of the two motors gradually converge to a given value through the dual closed-loop feedback of the single motor and the fine-tuning of the dual-motor coupling feedback loop. When the integral of the speed synchronization error is equal to Δθ, the phase catch-up is completed, the speeds of the two motors are restored to the given value, and the phase synchronization error Δθ converges to 0 at the same time, achieving simultaneous synchronization of speed and phase, that is, entering the stable operation stage, Δθ=0.

[0027] The present invention provides a control method for a dual permanent magnet synchronous motor same-speed and same-phase control system, the implementation subject is the aforementioned dual permanent magnet synchronous motor same-speed and same-phase control system, and the steps include:

[0028] Step S1, starting a dual permanent magnet synchronous motor same-speed and same-phase control system;

[0029] Step S2: The encoders on the two motors obtain the actual mechanical angle θ output during the operation of the motors. 1 ,θ 2 , and further calculate the phase synchronization error Δθ between the first motor and the second motor;

[0030] Step S3, determining whether the phase synchronization error Δθ satisfies Δθ≠0; if the determination result is yes, proceeding to step S4; if the determination result is no, returning to step S2;

[0031] Step S4, starting the synchronous controller after the two motors run stably and the speed reaches a given value;

[0032] Step S5, the synchronous controller calculates the synchronous compensation value Δθ according to Δθ comp , the speed compensation value Δe is output by the cross-coupling PI controller and fed back to the speed loop PI regulators in the two single-motor dual closed-loop vector control systems; wherein, negative feedback is performed on the speed PI regulator of the first motor, and positive feedback is performed on the speed PI regulator of the second motor.

[0033] Preferably, in the single-motor dual closed-loop vector control system:

[0034] Let the system input be a given speed n * , n * Deviation n from the actual speed value n * -nAfter passing through the speed loop PI regulator, the output q-axis stator current component given value i q * ;i q * Compared with the actual value of the q-axis current component i q The deviation value i q * -i q After passing through the q-axis current PI regulator, the given voltage Uq of the q-axis component is output * ; d-axis stator current component given value i d * (i d * =0) compared to the deviation value i of the actual value id of the d-axis stator current component d * -i d After passing through the d-axis current PI regulator, the output d-axis stator voltage component is the given value U d * ;

[0035] U q * with U d * After the inverse Park transformation, the given value U of the stator voltage on the α and β axes is obtained. α * , U β * ; U α * , U β * After SVPWM modulation, a PWM signal is obtained; the PWM signal is input into the inverter to control the on and off of the thyristor in the inverter to control the operation of the motor;

[0036] The inverter outputs a three-phase current signal i to the motor A 、i B 、i C After Clarke transformation and Park transformation, the output current i d 、i q ;

[0037] The encoder obtains the actual electrical angle θ e The actual speed value n is transmitted to the Park converter and the inverse Park converter, and the actual speed value n is output to the speed loop PI regulator for deviation calculation.

[0038] Preferably, the calculation formula of the phase synchronization error Δθ in step S2 is:

[0039] θ e1 =θ 1 *p n (1)

[0040] θ e2 =θ 2 *p n (2)

[0041]

[0042] Among them, θ e1 ,θ e2 are the actual electrical angles of the first motor and the second motor respectively, p n is the pole pair number; θ 1 ,θ 2 are the actual mechanical angles of the first motor and the second motor respectively, To use the mod function to convert θ 1 ,θ 2 The result of calculating the modulus of 2ρ and then converting the angle unit;

[0043] Preferably, Δθ in step S5 comp The conversion expression is:

[0044]

[0045] It can be seen from the above technical scheme that the dual permanent magnet synchronous motor same-speed and same-phase control system and control method thereof provided by the embodiment of the present invention. The system is composed of two single-motor dual closed-loop vector control systems and a synchronous controller in the form of a cross-coupling structure. The single-motor dual closed-loop vector control system includes a motor and a speed outer loop and a current inner loop, wherein the speed regulator and the current regulator are both PI controllers; an encoder is installed on the motor, and the encoder obtains the actual electrical angle and the actual speed value output during the operation of the motor; the synchronous controller is used to calculate the speed compensation value based on the phase angle synchronization error between the two motors and output it to the speed regulators in the two single-motor dual closed-loop vector control systems for one positive and one negative feedback compensation. The present invention adopts a PI control algorithm and a cross-coupling control structure to optimize the angle error to obtain the speed compensation value, ensuring that the dual motors still maintain speed and phase tracking synchronization when the load changes, so that the system has good robustness and rapidity, and effectively improves the synchronization performance and dynamic performance of the dual motor control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural diagram of the dual-motor same-speed and same-phase control system of the present invention.

[0047] Figure 2 This is the block diagram of vector control of single permanent magnet synchronous motor.

[0048] Figure 3 This is a flow chart of the angle error conversion of the present invention.

[0049] Figure 4 This is the motor speed diagram.

[0050] Figure 5 This is the speed and phase synchronization error waveform.

[0051] Figure 6 This is the structural diagram of the synchronous control principle of the first motor. DETAILED DESCRIPTION

[0052] The technical scheme and technical effects of the present invention are further elaborated in detail below in conjunction with the accompanying drawings of the present invention.

[0053] refer to Figure 1 As shown, the dual permanent magnet synchronous motor same-speed and same-phase control system provided by the present invention is composed of two single-motor double closed-loop vector control systems and a synchronous controller in a cross-coupling structure, wherein:

[0054] Single motor dual closed loop vector control system reference Figure 2As shown, it includes a motor and a speed outer loop and a current inner loop, wherein the speed regulator ASR and the current regulator ACR are both PI controllers; an encoder is installed on the motor, and the encoder obtains the actual electrical angle and the actual speed value output during the operation of the motor; the actual electrical angle can be expressed as the product of the actual mechanical angle and the number of pole pairs;

[0055] Synchronous Controller Reference Figure 1 As shown, the speed compensation value is calculated based on the phase angle synchronization error between the two motors and outputted to the speed regulators ASR in the two single-motor dual closed-loop vector control systems for one positive and one negative feedback compensation.

[0056] Figure 2 In the single motor dual closed loop vector control system shown:

[0057] Preferably, in a single motor dual closed loop vector control system:

[0058] Let the system input be a given speed n * , n * Deviation n from the actual speed value n * -nAfter passing through the speed loop PI regulator, the output q-axis stator current component given value i q * ;i q * Compared with the actual value of the q-axis current component i q The deviation value i q * -i q After passing through the q-axis current PI regulator, the given voltage Uq of the q-axis component is output * ; d-axis stator current component given value i d * (i d * =0) compared to the deviation value i of the actual value id of the d-axis stator current component d * -i d After passing through the d-axis current PI regulator, the output d-axis stator voltage component is the given value U d * ;

[0059] U q * with U d * After the inverse Park transformation, the given value U of the stator voltage on the α and β axes is obtained. α * , U β * ; U α * , U β* After SVPWM modulation, a PWM signal is obtained; the PWM signal is input into the inverter to control the on and off of the thyristor in the inverter to control the operation of the motor;

[0060] The three-phase current signal i output by the inverter to the motor A 、i B 、i C After Clarke transformation and Park transformation, the output current i d 、i q ; where i q As the input of the q-axis current PI regulator, i d As the input of the d-axis current PI regulator;

[0061] The encoder will obtain the actual electrical angle θ e It is transmitted to the Park converter and the anti-Park converter, and the actual speed value n is output to the speed loop PI regulator for deviation calculation.

[0062] In the system, let the inputs of the two single-motor dual-closed-loop vector control systems be both given speeds n ref , the expression for the phase angle synchronization error Δθ between the two motors is defined as:

[0063] θ e1 =θ 1 *p n (1)

[0064] θ e2 =θ 2 *p n (2)

[0065]

[0066] Among them, θ e1 ,θ e2 are the actual electrical angles of the first motor and the second motor respectively, p n is the pole pair number, p n =4;θ 1 ,θ 2 are the actual mechanical angles of the first motor and the second motor respectively (in rad), To use the mod function to convert θ 1 ,θ 2 The result of the angle conversion (radians to degrees) after taking the modulus of 2π is calculated; Δθ is used as the original input data of the synchronous controller.

[0067] Based on the phase angle synchronization error Δθ, a synchronous controller is designed to establish a cross-coupled feedback loop. The synchronous controller includes an angle error conversion module and a cross-coupled PI controller; the angle error conversion module is used to convert the input Δθ into a synchronous compensation value Δθ of (-180°, 180°) using a judgment algorithm. comp , Δθ comp The conversion expression is:

[0068]

[0069] The synchronous compensation value Δθ comp A cross-coupled PI controller is input, and the cross-coupled PI controller outputs a speed compensation value Δe which is fed back to the speed loop PI regulators in the two single-motor dual closed-loop vector control systems, wherein negative feedback is given to the speed PI regulator of the first motor, and positive feedback is given to the speed PI regulator of the second motor.

[0070] In the startup phase of the dual permanent magnet synchronous motor same speed and same phase control system: if there is an initial phase difference (in degrees) between the two motors, that is, Δθ≠0, the synchronous controller is started when the two motors run smoothly after startup and the actual speed reaches the given value ( Figure 4 The synchronous controller is started when the time is 0.25 seconds. Figure 5 The initial phase difference between the two motors is Δθ = 50°, and the introduced Δθ is converted into a synchronous compensation value Δθ through the angle error conversion module. comp , synchronous compensation value Δθ comp The input is to the cross-coupled PI controller, and the cross-coupled output speed compensation value Δe performs one positive and one negative feedback compensation on the two motor speed PI controllers. At this time, the speed of motor one decreases, and the speed of motor two increases. The two motors maintain the speed difference for a period of time to catch up with the phase difference, so that the phase difference gradually decreases. When the phase difference tends to 0, the input of the synchronous compensator also tends to 0, and the speed compensation value output by the synchronous compensator also tends to 0. At this time, the control system gradually converges the speed of the two motors to the given value through the double closed-loop feedback of the single motor and the fine-tuning of the dual motor coupling feedback loop. When the speed synchronization error integral is equal to Δθ, the phase is caught up, the speed of the two motors is restored to the given value, and the phase synchronization error converges to 0 at the same time, realizing the synchronization of speed and phase.

[0071] In the stable operation stage of the dual-motor system, the speed and phase of the two motors are the same, and there is no synchronization error. When the stable operation of the dual-motor system is disturbed by dynamic loads, the motor speed jumps (dynamic load disturbances cause the load torque T L1 change( Figure 6As can be seen in Figure 2, if the load suddenly increases and the speed decreases, the phase also jumps, and there is a speed synchronization error and a phase synchronization error between the two motors. At this time, the input Δθ of the synchronous controller is ≠ 0, and Δθ is converted into a synchronous compensation value Δθ by the angle error conversion module. comp , synchronous compensation value Δθ comp The input is sent to the cross-coupled PI controller, and the cross-coupled output speed compensation value Δe performs one positive and one negative feedback compensation on the two motor speed PI controllers. For example, when only motor one is disturbed (such as Figure 4 , t=0.6s), the speed of motor 1 first decreases, causing the phase of motor 1 to lag behind motor 2. At this time, Δθ<0, and the feedback compensation Δe output by the synchronous controller is less than 0. The synchronous controller obtains the speed compensation value based on the phase angle synchronization error information between the two motors, so that the two motors can compensate for the speed while indirectly compensating for the phase. The speed compensation value of motor 1 is positive, and the speed compensation value of motor 2 is negative. When the phase difference between the two motors tends to 0, the input of the synchronous compensator also tends to 0, and the speed compensation value output by the synchronous compensator also tends to 0. At this time, the control system gradually converges the speed of the two motors to the given value through the double closed-loop feedback of the single motor and the fine-tuning of the dual-motor coupling feedback loop. When the integral of the speed synchronization error is equal to Δθ, the phase is caught up, the speed of the two motors is restored to the given value, and the phase synchronization error converges to 0 at the same time, and finally the speed and phase are synchronized at the same time.

[0072] Furthermore, the present invention provides a control method for a dual permanent magnet synchronous motor same-speed and same-phase control system, the implementation subject is the aforementioned dual permanent magnet synchronous motor same-speed and same-phase control system, reference Figure 3 The flowchart shown includes the following steps:

[0073] Step S1, starting a dual permanent magnet synchronous motor same-speed and same-phase control system;

[0074] Step S2: The encoders on the two motors obtain the actual mechanical angle θ output during the operation of the motors. 1 ,θ 2 , and further calculate the phase synchronization error Δθ between the first motor and the second motor;

[0075] Step S3, determining whether the phase synchronization error Δθ satisfies Δθ≠0; if the determination result is yes, proceeding to step S4; if the determination result is no, returning to step S2;

[0076] Step S4: When the two motors are running smoothly and the actual speed reaches a given value n ref Then start the synchronous controller; (such as Figure 2 The synchronous controller is started at 0.25 seconds, and the motor speed is stabilized at a given value of 1500 rpm when the synchronous controller is introduced at 0.25 seconds);

[0077] Step S5: The synchronous controller calculates the synchronous compensation value Δθ according to Δθ. comp , the speed compensation value Δe is output by the cross-coupled PI controller and fed back to the speed loop PI regulators in the two single-motor dual closed-loop vector control systems; wherein, negative feedback is given to the speed PI regulator of the first motor, and positive feedback is given to the speed PI regulator of the second motor.

[0078] The calculation formula of the phase synchronization error Δθ in step S2 refers to the above formula (1-5); Δθ in step S5 comp The conversion expression of refers to the above formula (6).

[0079] Please refer to Figure 6 The synchronous control principle structure diagram of the motor 1 shown in the figure, ASR is the speed PI controller, G ACR (s) is the equivalent transfer function of the current loop. The electromagnetic torque equation is:

[0080]

[0081] The PMSM motion equation is as follows:

[0082]

[0083] Where, T e is the electromagnetic torque, L d and L q are the d-axis and q-axis inductances respectively; i d 、i q are the currents of the d-axis and q-axis respectively; T L1 is the motor load torque, and J is the moment of inertia.

[0084] H m is the remainder module, H J It is the angle conversion module. Both motors start without load (load torque T L1 , T L2 are all 0), when only motor 1 is disturbed (i.e. T L1 >0, such as Figure 4 , t=0.6s), the speed of motor 1 first decreases. This causes the phase of motor 1 to lag behind motor 2. At this time, Δθ<0, the feedback compensation Δe output by the synchronous controller is less than 0, and the subsequent steps refer to steps S1-S5. (When t=0.9, motor 2 is disturbed, T L2 >0 and T L1 =T L2 , the process is the same).

[0085] The present invention integrates the speed compensation and phase compensation that are independent of each other in the traditional cross-coupling structure, improves the input and output of the synchronous compensator and the algorithm logic, and designs a new cross-coupling synchronous controller. The control system structure is simplified, and a single coupling loop is used to achieve the effect of speed compensation and phase compensation dual coupling loops acting simultaneously.

[0086] The present invention combines the PI control algorithm and the cross-coupling control structure, establishes the coupling relationship of the dual-motor system state by introducing the phase synchronization error between the two motors, and designs a synchronous compensator for the phase synchronization error to ensure that the dual motors still maintain speed and phase tracking synchronization under load changes, so that the system has good robustness and rapidity, and effectively improves the synchronization performance of the dual-motor control system. By implementing the method of the present invention, the synchronization of the speed and phase of the dual motors under dynamic load conditions can be achieved simultaneously, with high synchronization accuracy and good dynamic performance.

[0087] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A dual permanent magnet synchronous motor same speed and same phase control system, characterized in that: It consists of two single-motor dual-closed-loop vector control systems and a synchronous controller in a cross-coupling structure, where: The single-motor dual-closed-loop vector control system includes a motor and speed outer loop and a current inner loop, wherein the speed regulator ASR and the current regulator ACR are both PI controllers; an encoder is installed on the motor, and the encoder obtains the actual electrical angle and actual speed value output during the operation of the motor; The synchronous controller is used to calculate the speed compensation value based on the phase angle synchronization error between the two motors and output it to the speed regulators ASR in the two single-motor dual closed-loop vector control systems for positive and negative feedback compensation.

2. The dual permanent magnet synchronous motor same speed and same phase control system according to claim 1, characterized in that: In the single motor dual closed loop vector control system: Let the system input be a given speed n * , n * Deviation n from the actual speed value n * -nAfter passing through the speed loop PI regulator, the output q-axis stator current component given value i q * ; i q * Compared with the actual value of the q-axis current component i q The deviation value i q * -i q After passing through the q-axis current PI regulator, the given voltage Uq of the q-axis component is output * ; d-axis stator current component given value i d * (i d * =0) compared to the deviation value i of the actual value id of the d-axis stator current component d * -i d After passing through the d-axis current PI regulator, the output d-axis stator voltage component is the given value U d * ; U q * with U d * After the inverse Park transformation, the given value U of the stator voltage on the α and β axes is obtained. α * , U β * ; U α * , U β * After SVPWM modulation, a PWM signal is obtained; the PWM signal is input into the inverter to control the on and off of the thyristor in the inverter to control the operation of the motor; The inverter outputs a three-phase current signal i to the motor A 、i B 、i C After Clarke transformation and Park transformation, the output current i d 、i q ; where i q As the input of the q-axis current PI regulator, i d As an input of the d-axis current PI regulator; The encoder obtains the actual electrical angle θ e The actual speed value n is transmitted to the Park converter and the inverse Park converter, and the actual speed value n is output to the speed loop PI regulator for deviation calculation.

3. The dual permanent magnet synchronous motor same speed and same phase control system according to claim 2, characterized in that: Assume that the inputs of the two single-motor dual-closed-loop vector control systems are both given speeds n ref , the expression for the phase angle synchronization error Δθ between the two motors is defined as: i e1 =θ1*p n i e2 =θ2*p n Among them, θ e1 ,θ e2 are the actual electrical angles of the first motor and the second motor respectively, p n is the number of pole pairs; θ1 and θ2 are the actual mechanical angles of the first motor and the second motor respectively. The calculation result is obtained by converting θ1 and θ2 modulo 2π using the mod function and then converting the angle units. The synchronous controller includes an angle error conversion module and a cross-coupled PI controller; The angle error conversion module is used to convert the input Δθ into a synchronous compensation value Δθ of (-180°, 180°) using a determination algorithm. comp , Δθ comp The conversion expression is: The synchronous compensation value Δθ comp The cross-coupled PI controller is input, and the cross-coupled PI controller outputs a speed compensation value Δe which is fed back to the speed loop PI regulators in the two single-motor dual closed-loop vector control systems, wherein negative feedback is performed on the speed PI regulator of the first motor, and positive feedback is performed on the speed PI regulator of the second motor.

4. The dual permanent magnet synchronous motor same speed and same phase control system as claimed in claim 3, characterized in that: During the startup phase of the dual permanent magnet synchronous motor same-speed and same-phase control system: If there is an initial phase difference between the two motors, that is, Δθ≠0, after starting, the two motors run smoothly and the actual speed reaches the given value n ref The synchronous controller is started at this time; the system uses the double closed-loop feedback of the single motor and the fine-tuning of the dual motor coupling feedback loop to gradually converge the speeds of the two motors to the given value. When the integral of the speed synchronization error is equal to Δθ, the phase catch-up is completed, and the speeds of the two motors are restored to the given value n ref , the phase synchronization error Δθ converges to 0 at the same time, achieving simultaneous synchronization of speed and phase, that is, entering the stable operation stage, Δθ=0.

5. A control method for a dual permanent magnet synchronous motor same speed and same phase control system, characterized in that: The implementation subject is the dual permanent magnet synchronous motor same-speed and same-phase control system according to any one of claims 1 to 4, and the steps include: Step S1, starting a dual permanent magnet synchronous motor same-speed and same-phase control system; Step S2, the encoders on the two motors obtain the actual mechanical angles θ1 and θ2 output during the operation of the motors, and further calculate the phase synchronization error Δθ between the first motor and the second motor; Step S3, judging whether the phase synchronization error Δθ satisfies Δθ≠0; if the judgment result is yes, proceeding to step S4; if the judgment result is no, returning to step S2; Step S4: When the two motors are running smoothly and the actual speeds reach the given value n ref Then start the synchronous controller; Step S5, the synchronous controller calculates the synchronous compensation value Δθ according to Δθ comp , the speed compensation value Δe is output by the cross-coupling PI controller and fed back to the speed loop PI regulators in the two single-motor dual closed-loop vector control systems; wherein, negative feedback is performed on the speed PI regulator of the first motor, and positive feedback is performed on the speed PI regulator of the second motor.

6. The control method of the dual permanent magnet synchronous motor same speed and same phase control system according to claim 5, characterized in that: The calculation formula of the phase synchronization error Δθ in step S2 is: i e1 =θ1*p n i e2 =θ2*p n Among them, θ e1 ,θ e2 are the actual electrical angles of the first motor and the second motor respectively, p n is the number of pole pairs; θ1 and θ2 are the actual mechanical angles of the first motor and the second motor respectively. The result of converting θ1 and θ2 modulo 2ρ using the mod function and then converting the angle units.

7. The control method of the dual permanent magnet synchronous motor same speed and same phase control system according to claim 6, characterized in that: In step S5, Δθ comp The conversion expression is:

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