Synchronous control method for double permanent magnet synchronous motors based on common-mode and differential-mode separation

Abstract

The invention relates to a synchronous control method for double permanent magnet synchronous motors based on common-mode and differential-mode separation, and belongs to the technical field of permanent magnet synchronous motor control. The method comprises the following steps: constructing a common-mode and differential-mode separated control loop which comprises a common-mode loop, a differential-mode loop, a first current loop and a second current loop; respectively acquiring motor parameters of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor and inputting the motor parameters into a common-mode loop and a differential-mode loop; respectively generating a first reference current and a second reference current based on the motor parameters, the common-mode loop and the differential-mode loop, and inputting the first reference current and the second reference current into a first current loop and a second current loop; and the first current loop and the second current loop generate a first current magnitude and a second current magnitude respectively, and a first torque control quantity and a second torque control quantity for controlling the first permanent magnet synchronous motor and the second permanent magnet synchronous motor are obtained according to the first current magnitude and the second current magnitude, so that synchronous control of the double permanent magnet synchronous motors is realized. According to the invention, the problem of target contradiction in cross-coupling synchronous control is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet synchronous motor control, and relates to a synchronous control method for dual permanent magnet synchronous motors based on common-mode and differential-mode separation. Background Technique

[0002] With the rapid development of fields such as industrial automation, precision manufacturing, and new energy, the combination of power electronics technology and motor control theory has given rise to the widespread application of high-performance drive systems. Permanent magnet synchronous motors (PMSMs) have become the core power devices in the field of high-speed and high-precision drives due to their advantages such as high efficiency, high power density, excellent dynamic response characteristics, and wide speed regulation range. Especially in high-demand scenarios such as aerospace, numerical control machine tools, electric vehicles, and robot joints, the torque output accuracy and speed stability of PMSMs directly determine the overall performance of the system. However, with the continuous improvement of the requirements for output power, energy efficiency ratio, and reliability of industrial equipment, single-motor drive systems have gradually revealed defects such as insufficient power upper limit and poor fault tolerance. Against this background, dual permanent magnet synchronous motor or multi-motor cooperative drive systems have become an inevitable choice to solve the above problems. By parallel or cooperative operation of two or more motors, the system can not only achieve power superposition and redundant fault tolerance, but also extend the equipment life through load balancing and reduce the risk of single-point failures. However, the introduction of multi-motor systems also brings complex synchronous control challenges. How to achieve the consistency of the dynamic responses of dual motors and the collaborative optimization of disturbance rejection capabilities has become the key technical bottleneck restricting system performance.

[0003] Currently, the mainstream strategies for dual-motor synchronous control mainly include master-slave control, virtual spindle control, and cross-coupling control. In the master-slave control scheme, one motor is used as the master controller, and its output is directly used as the given command for the slave motor. Although this architecture simplifies the system design, since the dynamic response of the slave motor completely depends on the output of the master motor, when the slave motor encounters load mutations or parameter perturbations, the master motor cannot perceive and adjust in real time, resulting in the accumulation of synchronous errors. In addition, the master-slave control lacks a two-way interaction mechanism, and the disturbances of the slave motor cannot be fed back to the master motor control loop, significantly limiting the disturbance rejection ability of the system and making it difficult to meet the requirements of high-precision synchronous scenarios.

[0004] The virtual spindle control scheme maps the motion states of two motors onto the same virtual reference axis by constructing a virtual mechanical axis model, and theoretically can achieve dynamic synchronization. However, there are significant defects in the actual application of this scheme: First, the dynamic characteristics of the virtual axis need to strictly match the parameters of the actual mechanical system, and the mismatch of motor parameters or the non-linear characteristics of the load will cause static errors in speed tracking; Second, when the load distribution of the two motors is uneven, it is difficult for the dynamic response of the virtual axis to take into account the real-time state differences of the two motors, which is likely to cause torque oscillation; Third, the ability of the system to suppress disturbance signals depends on the stiffness design of the virtual axis. Excessive stiffness may cause system instability, while too low stiffness will lead to a decrease in synchronization accuracy.

[0005] As the most widely used current strategy, cross-coupling control attempts to balance the contradiction between speed tracking and synchronization control by introducing cross-feedback compensation into the speed closed-loop of two motors. Its core idea is to feedback the speed deviation of the two motors into the control quantity of a single motor, forcing the two motors to adjust collaboratively. However, the interaction between the speed closed-loop and the cross-coupling feedback will introduce additional phase lag, making it difficult to compromise between the dynamic response speed and the synchronization accuracy.

[0006] Therefore, there is an urgent need for a synchronization control method that can reconstruct the control architecture and achieve common-mode and differential-mode separation processing to solve the target contradiction problem in cross-coupling synchronization control and obtain better synchronization performance. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a synchronization control method for dual permanent magnet synchronous motors based on common-mode and differential-mode separation to solve the target contradiction problem in cross-coupling synchronization control and achieve a higher-performance synchronization effect.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] A synchronization control method for dual permanent magnet synchronous motors based on common-mode and differential-mode separation, which includes:

[0010] First, construct a control loop for common-mode and differential-mode separation, which includes a common-mode loop, a differential-mode loop, a first current loop, and a second current loop;

[0011] Then, collect the motor parameters of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor and input them into the common-mode loop and the differential-mode loop;

[0012] Secondly, the common-mode loop generates a first reference current based on the motor parameters, and this first reference current is respectively input into the first current loop and the second current loop; the differential-mode loop generates a second reference current based on the motor parameters, and this second reference current is respectively input into the first current loop and the second current loop;

[0013] Again, the first current loop generates a first current quantity according to the first reference current and the second reference current, and combines the first current quantity and the torque coefficient of the first permanent magnet synchronous motor to obtain a first electromagnetic torque control quantity; the second current loop generates a second current quantity according to the first reference current and the second reference current, and combines the second current quantity and the torque coefficient of the second permanent magnet synchronous motor to obtain a second electromagnetic torque control quantity;

[0014] Finally, the first torque control quantity and the second torque control quantity are respectively applied to the first permanent magnet synchronous motor and the second permanent magnet synchronous motor to achieve synchronous control of the dual permanent magnet synchronous motors.

[0015] Furthermore, the motor parameters input into the common-mode loop include the moments of inertia, electromagnetic torques, and load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0016] The common-mode component T of the electromagnetic torque is calculated according to the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor ec , where T e1 and T e2 respectively represent the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor;

[0017] The common-mode component T of the load disturbance is calculated according to the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor Lc , where T L1 and T L2 respectively represent the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0018] The common-mode loop includes a unified speed controller, which generates a first reference current according to the input reference speed ω * and the feedback speed ω f where the feedback speed ω f is calculated by the following formula:

[0019]

[0020] In the formula, s represents the differential operator, and J1 and J2 respectively represent the moments of inertia of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0021] Furthermore, the unified speed controller is a PI controller.

[0022] Furthermore, the motor parameters input into the common-mode loop include the moments of inertia, electromagnetic torques, and load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0023] Based on the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, the common-mode component T of the electromagnetic torque is calculated through the following system of equations ec and the differential-mode component T ed :

[0024]

[0025] Based on the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, the common-mode component T of the load disturbance is respectively calculated Lc and the differential-mode component T Ld ,

[0026] A synchronous controller is included in the differential-mode loop. The synchronous controller generates a second reference current according to the position deviation δ between the first permanent magnet synchronous motor and the second permanent magnet synchronous motor wherein, the position deviation δ is calculated by the following formula:

[0027]

[0028] Furthermore, the first current loop generates a first current quantity according to the first reference current and the second reference current, and combines the first current quantity and the torque coefficient of the first permanent magnet synchronous motor to obtain a first electromagnetic torque control quantity. This process can be expressed as:

[0029]

[0030] In the formula, T e1 ′ represents the first electromagnetic torque control quantity, K t1 represents the torque coefficient of the first permanent magnet synchronous motor, L c represents the transfer function of the current loop, and respectively represent the first reference current and the second reference current;

[0031] The second current loop generates a second current quantity according to the first reference current and the second reference current, and combines the second current quantity and the torque coefficient of the second permanent magnet synchronous motor to obtain a second electromagnetic torque control quantity. This process can be expressed as:

[0032]

[0033]

[0034] In the formula, T e2 ′ represents the second electromagnetic torque control quantity, K t2 represents the torque coefficient of the second permanent magnet synchronous motor.

[0035] The beneficial effects of the present invention are as follows: Based on the technical concept of common-mode and differential-mode separation, the present invention proposes a synchronous control method for dual permanent magnet synchronous motors based on common-mode and differential-mode separation. This method decouples the objectives of synchronous control and speed tracking. Specifically, the system control loop is divided into a common-mode loop and a differential-mode loop, and a unified speed controller and a synchronous controller are used for common-mode regulation and differential-mode regulation respectively. The adjustment of the synchronous controller does not affect the weighted average speed, that is, it does not interact with the unified speed controller. Similarly, the weighted average speed is independent of the differential-mode factors. Therefore, when the common-mode loop changes, even if there are oscillations or overshoots in the unified speed controller, the synchronous controller can maintain an ideal state, improving the synchronous performance of the dual-motor system and solving the inherent contradictions existing in the cross-coupling structure. In addition, since the mechanical collision between the two motors can also be regarded as a non-linear differential-mode disturbance, the synchronous control method proposed by the present invention can adjust the collision of the dual-motor system.

[0036] Experimental results show that compared with the traditional cross-coupling method, the synchronous control method of common-mode and differential-mode separation proposed by the present invention has significantly improved synchronous accuracy and can achieve the collision recovery of the dual-motor system. In addition, the present invention can also be extended to the synchronous control of multi-motor systems, with excellent scalability.

[0037] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail with reference to the accompanying drawings, where:

[0039] Figure 1 is a schematic diagram of the control structure for common-mode and differential-mode separation;

[0040] Figure 2 is a schematic diagram of the principle of the synchronous controller;

[0041] Figure 3 is the position deviation between the two motors when the dual electrodes are accelerated to the rated speed;

[0042] Figure 4 is a comparison of the synchronous effects between the method of the present invention and the traditional coupling control method;

[0043] Figure 5 (a) is a schematic diagram of the position difference curve under the synchronous control method of common-mode and differential-mode separation after the mechanical collision of the dual-electrode system;

[0044] Figure 5 (b) is a schematic diagram of the current curve under the common-mode and differential-mode separation and synchronization control method after mechanical collision of the dual-electrode system. Specific implementation manners

[0045] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0046] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which does not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0047] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only for illustrative purposes and should not be construed as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0048] The mathematical model of a single permanent magnet synchronous motor can be expressed as:

[0049]

[0050] Among them, u d and u q are the d-axis and q-axis stator voltages respectively; i d and i q are the d-axis and q-axis stator currents respectively; ω e is the electrical angular velocity; ψ f is the rotor permanent magnet flux linkage; L d and L q are the d-axis and q-axis inductances respectively.

[0051] In addition, the torque equation of the motor is as follows:

[0052]

[0053] Where p n is the number of pole pairs.

[0054] Then, the simplified dynamic equation of a dual permanent magnet synchronous motor system can be approximately expressed as:

[0055]

[0056] Where x = 1, 2, representing the first permanent magnet synchronous motor and the second permanent magnet synchronous motor. θ x represents the angular position of the permanent magnet synchronous motor, ω x represents the angular velocity of the permanent magnet synchronous motor, K tx represents the torque coefficient of the permanent magnet synchronous motor, i x represents the current of the permanent magnet synchronous motor, J x represents the moment of inertia of the permanent magnet synchronous motor, T Lx represents the load disturbance of the permanent magnet synchronous motor, θ max represents the mechanical clearance between the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, and δ represents the position deviation between the first permanent magnet synchronous motor and the second permanent magnet synchronous motor. represents the second derivative of θ x , represents the first derivative of ω x .

[0057] The disturbances T L1 and T L2 of the two motors can also be divided into a common-mode disturbance T Lc and a differential-mode disturbance T Ld , as shown in the following equation (2):

[0058]

[0059] As Figure 1 shown is the control structure for common-mode and differential-mode separation. In servo applications, the innermost control loop has the fastest response speed. Therefore, based on the traditional cross-coupling control method, the output of the synchronization controller is directly compensated to the current reference value, and the input of the synchronization controller is the difference δ between the positions of the two motors. The two motors share a speed controller, and the speed feedback ω f of this speed controller is obtained by weighted averaging based on the moments of inertia of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively.

[0060] The outputs of the unified speed controller and the synchronization controller are respectively expressed as and and According to the torque coefficients K of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor t allocate proportionally.

[0061] Among them, the unified speed controller adopts a PI controller to achieve the control purpose of improving the synchronization accuracy of the dual-motor system. The transfer function of the unified speed controller can be expressed as:

[0062]

[0063] Among them, k p and k i are the proportional coefficient and the integral coefficient respectively. S is the differential operator.

[0064] The synchronization controller is designed according to the collision model, mechanical clearance, disturbance frequency characteristics and real-time operating state of the dual-motor system, and its structure is as Figure 2 shown, where LPF represents a low-pass filter. The equation of the nonlinear function is expressed as:

[0065] k = max(k1, k2)(4)

[0066]

[0067] Among them, α is the control parameter.

[0068] Figure 2 In, the recovery coefficient is expressed as:

[0069]

[0070] Among them, β is the control parameter.

[0071] According to Figure 1 it can be obtained that the electromagnetic torques of the two motors can be expressed as:

[0072]

[0073] Among them, L cx represents the transfer function of the current loop including the motor itself, the current controller, the filter and the inverter, and x = 1, 2. By designing the current loops of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, it can be assumed that L c1 = L c2 = L c . Therefore, the electromagnetic torques of the two motors can be separated into common-mode and differential-mode components, that is:

[0074]

[0075] Combined with Equation (1) and Equation (5), the speed feedback ω fExpressed as:

[0076]

[0077] ω f only contains common - mode perturbations. s represents the differential operator. When calculating ω f it can be calculated by means such as sliding window and filtering, or an improved differential algorithm to minimize errors.

[0078] Similarly, it can be deduced that the input δ of the synchronous controller is expressed as:

[0079]

[0080] According to the above analysis, the unified speed controller and the synchronous controller are respectively used for common - mode regulation and differential - mode regulation. It can be verified that the adjustment of the synchronous controller will not affect the weighted average speed, that is, it will not interact with the unified speed controller.

[0081] The position deviation δ contains factors affecting the synchronization of the dual - motor system, including perturbations and parameter differences, and these factors are defined as differential - mode factors. Therefore, Figure 1 the entire control structure in is divided into a common - mode loop and a differential - mode loop. The weighted average speed is independent of the differential - mode factors. Similarly, when the common - mode loop changes, even if there are oscillations or overshoots in the unified speed controller, the synchronization performance can still remain ideal, improving the synchronization performance.

[0082] In addition, to design the current loops of the two permanent - magnet synchronous motors to have the same performance, that is, L c1 = L c2 = L c , dead - beat control can be adopted, and the dead - beat voltage vector satisfies:

[0083]

[0084] where M, G, and F are the coefficient matrices of the discretized mathematical model, and e dq is the back - electromotive force vector. During the transient process, it is considered that the given value of the current loop is a constant value, that is,

[0085] Based on the above principle, an embodiment of the present invention proposes a synchronous control method for dual permanent - magnet synchronous motors with common - mode and differential - mode separation, and this method includes:

[0086] 1) Construct a control structure with common - mode and differential - mode separation, and divide the control quantities of the permanent - magnet synchronous motor into two parts: common - mode and differential - mode, where the control quantities of the permanent - magnet synchronous motor include speed, angle, current, and torque.

[0087] The control structure for common-mode and differential-mode separation includes dividing the control loop of the dual permanent magnet synchronous motor into a common-mode loop and a differential-mode loop. A unified speed controller is set in the common-mode loop, and the input parameters of the unified speed controller include the reference speed ω * and the feedback speed ω f , and the output parameter is A synchronous controller is set in the differential-mode loop. The input parameters of the synchronous controller include the position deviation δ between the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, and the output parameter is Specifically, as Figure 2 shown, multiplying i DM by the recovery coefficient r can obtain

[0088] 2) Collect the parameters of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively, including the moment of inertia J1 and J2, the electromagnetic torque T e1 and T e2 , the load disturbance T L1 and T L2 ;

[0089] According to the electromagnetic torques T e1 and T e2 of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, calculate the common-mode component T ec and differential-mode component T ed of the electromagnetic torque. The specific calculation process is to substitute T e1 and T e2 into Equation (4) to solve the system of equations to calculate T ec and T ed ; According to the load disturbances T L1 and T L2 calculate the common-mode component T Lc and differential-mode component T Ld of the load disturbance, which can be specifically calculated according to formula (2);

[0090] In other embodiments of the present invention, T and T ec and T ed can also be calculated according to the torque coefficient, transfer function and

[0091] Substitute the moment of inertia J1 and J2, the common-mode component T ec of the electromagnetic torque and the common-mode component T Lc of the load disturbance into Equation (5) to calculate the feedback speed ω f ; Substitute the moment of inertia J1 and J2, the common-mode component T ec and differential-mode component T ed of the electromagnetic torque, the common-mode component T Lc and differential-mode component TLd Substitute into Equation (6) to calculate the position deviation δ between the two motors.

[0092] 3) Obtain the reference speed ω * , and input ω * and ω f into the unified speed controller to generate Input δ into the synchronization controller to generate

[0093] 4) Multiply and by a coefficient respectively and input them into the current loop of the second permanent magnet synchronous motor. Calculate the electromagnetic torque control amount of the second permanent magnet synchronous motor according to the transfer function and torque coefficient, that is:

[0094]

[0095] Input and into the current loop of the first permanent magnet synchronous motor. Calculate the electromagnetic torque control amount of the first permanent magnet synchronous motor according to the transfer function and torque coefficient, that is:

[0096]

[0097] Apply T e1 ′ and T e2 ′ to the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively to control their operations, so as to realize the synchronous control of the dual permanent magnet synchronous motors.

[0098] Program the synchronous control method of common-mode and differential-mode separation described in the above embodiments and embed it in the DSP, and then conduct experimental verification of the method proposed by the present invention on the dual-motor experimental platform.

[0099] First, start the dual-motor system and run it to the rated speed. It can be known from Figure 3 that under the control of the method of the present invention, the mechanical clearance of the dual-electrode system is about ±0.001 rad. It can be seen that by adopting the control method of the present invention, the position deviation of the dual motors can be controlled within 1 / 3 of the mechanical error, and the synchronous control effect is good.

[0100] Then, after the mechanical collision of the dual-motor system, execute the synchronous control method of common-mode and differential-mode separation through the upper computer command. Through Figure 4 as shown, it can be seen that after adopting the common-mode and differential-mode separation control method proposed by the present invention, the position difference of the dual electrodes is significantly reduced, and the synchronous performance is significantly improved.

[0101] Secondly, after the mechanical collision of the dual-motor system, execute the synchronous control method of common-mode and differential-mode separation through the upper computer command. ThroughFigure 5 (a) It can be seen that the dual-motor system completed the collision recovery within 1 s after implementing the synchronous control method for common-mode and differential-mode separation. From Figure 5 (b) It can be seen that before implementing the synchronous control method for common-mode and differential-mode separation, the currents i of the two motors q were almost the same, indicating that only common-mode regulation existed in the dual-electrode system at this time. After implementing the synchronous control method for common-mode and differential-mode separation, the common-mode and differential-mode quantities were successfully separated, and the effect of adjusting the collision recovery was excellent.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A synchronous control method for a dual permanent magnet synchronous motor based on common mode and differential mode separation, characterized in that, The method includes: Firstly, construct a control loop for common-mode and differential-mode separation, which includes a common-mode loop, a differential-mode loop, a first current loop, and a second current loop; Secondly, collect the motor parameters of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively and input them into the common-mode loop and the differential-mode loop; Thirdly, the common-mode loop generates a first reference current based on the motor parameters, and this first reference current is input into the first current loop and the second current loop respectively; the differential-mode loop generates a second reference current based on the motor parameters, and this second reference current is input into the first current loop and the second current loop respectively; Then, the first current loop generates a first current quantity according to the first reference current and the second reference current, and combines this first current quantity with the torque coefficient of the first permanent magnet synchronous motor to obtain a first electromagnetic torque control quantity; the second current loop generates a second current quantity according to the first reference current and the second reference current, and combines this second current quantity with the torque coefficient of the second permanent magnet synchronous motor to obtain a second electromagnetic torque control quantity; Finally, apply the first torque control quantity and the second torque control quantity to the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively to achieve synchronous control of the dual permanent magnet synchronous motors.

2. The method according to claim 1, wherein The motor parameters input into the common-mode loop include the moment of inertia, electromagnetic torque, and load disturbance of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor; Calculate the common-mode component \(T\) of the electromagnetic torque based on the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor ec , where \(T\) e1 and \(T\) e2 represent the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, respectively; Calculate the common-mode component T of the load disturbance based on the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor Lc , where T L1 and T L2 represent the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, respectively.

3. A method according to claim 2, characterized in that The common-mode circuit includes a unified speed controller, and the unified speed controller generates a first reference current according to the input reference speed ω * and the feedback speed ω f The feedback speed ω is calculated by the following formula: f is calculated by the following formula: In the formula, s represents the differential operator, and J1 and J2 respectively represent the moment of inertia of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

4. A method according to claim 3, characterized in that, The unified speed controller is a PI controller.

5. A method according to claim 1, wherein The motor parameters input into the common-mode loop include the moment of inertia, electromagnetic torque, and load disturbance of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor; According to the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, the common-mode component T ec and the differential-mode component T ed of the electromagnetic torque are calculated through the following system of equations: Wherein, T e1 and T e2 respectively represent the electromagnetic torques of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor; Calculate the common-mode component T of the load disturbance according to the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively Lc and the differential-mode component T Ld , where T L1 and T L2 represent the load disturbances of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor respectively.

6. A method according to claim 5, characterized in that, The differential-mode circuit includes a synchronization controller, and the synchronization controller generates a second reference current according to the position deviation δ between the first permanent magnet synchronous motor and the second permanent magnet synchronous motor. Wherein, the position deviation δ is calculated by the following formula: In the formula, s represents the differential operator, and J1 and J2 respectively represent the moment of inertia of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

7. A method according to claim 1, characterized in that The first electromagnetic torque control quantity is expressed as: where K t1 represents the torque coefficient of the first permanent magnet synchronous motor, L c represents the transfer function of the current loop, and represent the first reference current and the second reference current respectively; The second electromagnetic torque control quantity is expressed as: where K t2 represents the torque coefficient of the second permanent magnet synchronous motor.

Images