A Decoupling Modeling Method for Multi-channel Permanent Magnet Synchronous Motors

Abstract

This invention provides a decoupling modeling method for multi-channel permanent magnet synchronous motors, belonging to the field of motor decoupling modeling technology. It solves the problems of strong inter-channel coupling and poor independence in existing multi-channel motors. The technical solution includes the following steps: S1: Establishing a mathematical model of a dual-channel permanent magnet synchronous motor in a synchronous rotating coordinate system; S2: Proposing a novel decoupling matrix H2; S3: Obtaining the mathematical model of decoupling the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system; S4: Proposing a novel decoupling matrix H2 based on the multi-channel permanent magnet synchronous motor. n The beneficial effects of this invention are as follows: the novel decoupling matrix proposed in this invention is easy to extend to multi-channel motors, the matrix is ​​simple to construct and easy to obtain, eliminating the complex calculations required for traditional decoupling matrix construction, and the matrix application is not limited to the symmetric or asymmetric type of motor.

Description

Technical Field

[0001] This invention relates to the field of motor decoupling modeling technology, and in particular to a decoupling modeling method for multi-channel permanent magnet synchronous motors. Background Technology

[0002] Previously, the control technology for three-phase permanent magnet synchronous motors was quite mature and widely used in industry. With the development of science and technology, multiphase motors, with their advantages of high torque density, low torque ripple, and strong fault tolerance, have attracted increasing attention from scholars. However, as the number of motor phases increases, the control strategy for multiphase motors becomes more complex. Therefore, multi-channel motors using modular unit control have emerged. A multi-channel motor combines every three phases of the multiphase motor windings into one channel, thus forming a multi-channel motor. Each channel uses an independent battery pack and inverter for power supply and control, which can greatly improve the system's fault tolerance and applicability.

[0003] Currently, existing modeling methods for multi-channel motors mainly include those based on multi-d-q coordinate transformation and those based on vector space decoupling. Since the latter separates subspaces related to and unrelated to electromechanical energy conversion, the vector space decoupling method is more commonly used. However, in the existing patent "Vector Control Method for Dual Three-Phase Permanent Magnet Motors Based on Proportional Resonance Regulator" (application number: 201310373118.4), the decoupled harmonic current components exhibit AC components in a synchronous rotating coordinate system, placing higher demands on the design of subsequent regulators. Furthermore, the multi-d-q coordinate transformation modeling method has not received much attention or application due to the unresolved coupling inductance between channels. Existing technologies cannot treat multi-channel motors as a superposition of several single-channel motors, still requiring complex algorithm design and significant time costs for industrial applications.

[0004] How to solve the above problems is the subject of this invention. Summary of the Invention

[0005] The purpose of this invention is to provide a decoupling modeling method for multi-channel permanent magnet synchronous motors; it solves the problems of strong inter-channel coupling and poor independence in existing multi-channel motors; the decoupling matrix is ​​easy to extend to multi-channel motors, the matrix construction is simple and easy to obtain, eliminating the complex calculations required for traditional decoupling matrix construction, and the matrix application is not limited to the symmetric or asymmetric type of motor.

[0006] To achieve the above-mentioned objectives, the present invention adopts a technical solution that includes the following steps:

[0007] S1: Establish a mathematical model of the dual-channel permanent magnet synchronous motor in a synchronous rotating coordinate system, including voltage equations, flux linkage equations, and torque equations. From the equations, it can be concluded that the mathematical model based on the dual d-q coordinate transformation is independent of the phase angle between the windings of the channel motor, making the subsequent application of the decoupling matrix unrestricted by whether the motor is symmetrical or asymmetrical.

[0008] S2: For the coupled inductance matrix L in the voltage equation of a dual-channel permanent magnet synchronous motor, a decoupling matrix H2 is proposed to eliminate the coupled inductance between channels and obtain the diagonalized inductance matrix L. * ;

[0009] S3: Apply the decoupling matrix H2 to the mathematical model of the dual-channel permanent magnet synchronous motor to obtain the mathematical model of decoupling of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system, thereby solving the problem of strong coupling between channels in the channel motor and making each channel independent of each other.

[0010] S4: The proposed decoupling matrix H2 is extended to multi-channel motors, and a decoupling matrix H2 based on multi-channel permanent magnet synchronous motors is proposed. n The matrix is ​​simple to construct and easy to obtain, making it easy to extend its application to multi-channel motors and eliminating the complex calculations required for constructing decoupling matrices in the traditional way.

[0011] In step S1, the dual-channel permanent magnet synchronous motor refers to a motor in which the A, B, and C phase windings of a traditional six-phase motor form the first channel, and the U, V, and W phase windings form the second channel. Therefore, a dual-channel permanent magnet synchronous motor is constructed. The mathematical model of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system is as follows:

[0012] (1)

[0013] Among them, u dq = [u d1 u q1 u d2 u q2 ] T R = diag[r rrr],i dq = [i d1 i q1 i d2 i q2 ] T , ψ dq =[ψ d1 ψ q1 ψ d2 ψ q2 ] T In the formula, u d1 u q1 ud2 u q2 Let r be the stator voltage, r be the stator resistance, and i be the stator voltage. d1 i q1 i d2 i q2 For stator current, ψ d1 ψ q1 ψ d2 ψ q2 For the motor flux linkage, ω e The electric angular velocity of the motor;

[0014] The coefficient matrix J is represented as:

[0015] (2)

[0016] The flux linkage equation is expressed as:

[0017] (3)

[0018] Where λ = [1 0 1 0] T ψf is the flux linkage of the permanent magnet;

[0019] The coupled inductance matrix L is represented as:

[0020] (4)

[0021] In the formula, L d L q These are the components of the motor inductance along the d-axis and q-axis, respectively. dd L qq For a dual-channel motor, the coupling inductor is used.

[0022] The torque equation is expressed as:

[0023] (5)

[0024] In the formula, T e p represents the electromagnetic torque of the motor. n This indicates the number of pole pairs of the motor.

[0025] In step S2, for the coupled inductance matrix L in the voltage equation of the dual-channel motor, a decoupling matrix H2 is expressed as:

[0026] (6)

[0027] The coupling inductance matrix L is orthogonally transformed using the decoupling matrix H2 to eliminate coupling terms in L, resulting in the diagonal inductance matrix L. * Represented as:

[0028] (7).

[0029] In step S3, the decoupling matrix H2 is applied to the mathematical model of the dual-channel motor in the synchronous rotating coordinate system, specifically as follows:

[0030] (8)

[0031] Among them, u DQ = [u D1 u Q1 u D2 u Q2 ] T i DQ = [i D1 i Q1 i D2 i Q2 ] T , ψ DQ = [ψ D1 ψ Q1 ψ D2 ψ Q2 ] T In the formula, u D1 u Q1 u D2 u Q2 To decouple the stator voltage, i D1 i Q1 i D2 i Q2 To decouple the stator current, ψ D1 ψ Q1 ψ D2 ψ Q2 To decouple the motor flux;

[0032] Transformed coefficient matrix J * Represented as:

[0033] (9)

[0034] The decoupled flux linkage equation is expressed as:

[0035] (10)

[0036] Specifically, λ * = [sqrt(2) 0 0 0] T ;

[0037] The torque equation, after decoupling, is expressed as:

[0038] (11)

[0039] In the formula, T EThis represents the decoupled electromagnetic torque, thus obtaining the mathematical model of the dual-channel permanent magnet synchronous motor under the decoupling modeling method;

[0040] The current components of the proposed decoupling modeling method in the synchronous rotating coordinate system are as follows:

[0041] (12).

[0042] In step S4, the proposed decoupling matrix is ​​extended and applied to multi-channel motors, and a decoupling matrix H based on multi-channel permanent magnet synchronous motors is proposed. n Represented as:

[0043] (13)

[0044] Where n represents the number of channels, and takes the value n = 2k, k∈N * Specifically, H0 is represented as:

[0045] (14)

[0046] After decoupling, the electromagnetic torque of the multi-channel motor is the superposition of the torques from multiple channels, expressed as:

[0047] (15).

[0048] Among them, T k This represents the electromagnetic torque of the motor in each channel after decoupling.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] (1) Compared with the traditional motor model based on vector space decoupling modeling, there is the problem that the harmonic current components between channels are AC quantities. In terms of control, the bandwidth of the PI regulator is limited, and the harmonic current components of the channels cannot be effectively suppressed. It is necessary to add regulator optimization design work in the future. However, the current components of each channel after the dual d-q decoupling modeling of this invention are DC quantities, which are not subject to the above restrictions. The traditional PI regulator can be used for effective control, saving the tedious work of subsequent regulator optimization.

[0051] (2) Compared with the traditional modeling method based on multiple d-q coordinate transformations, the proposed novel channel decoupling modeling method can eliminate the coupling inductance between channels, making the inductance matrix in the motor model a diagonal matrix, thus solving the problem of strong coupling between channels in the traditional method. This makes each channel independent of each other, which is convenient for independent control of each channel in the modular structure of multi-channel motors and has broad application prospects.

[0052] (3) Compared with traditional multi-channel motors, decoupled multi-channel motors can be regarded as the superposition of multiple single-channel motors, thus enabling the mature control methods of single-channel motors to be applied to multi-channel motor control systems, greatly reducing the algorithm design time of multi-channel motor control systems.

[0053] (4) The proposed decoupling matrix is ​​easy to extend to multi-channel motors. The matrix is ​​simple to construct and easy to obtain, eliminating the complex calculations required for traditional decoupling matrix construction. Moreover, the decoupling method is based on the multi-d-q coordinate transformation modeling method, which is independent of the phase angle between the windings of each channel motor. That is, the application of the decoupling matrix is ​​not limited to the symmetric or asymmetric type of motor. Attached Figure Description

[0054] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0055] Figure 1 This is a framework diagram of the multi-channel permanent magnet synchronous motor decoupling modeling method of the present invention;

[0056] Figure 2 This is a schematic diagram illustrating the control method of the present invention based on a dual-channel permanent magnet synchronous motor under the decoupling modeling method of the present invention;

[0057] Figure 3 This is a schematic diagram of a 2kW dual-channel permanent magnet synchronous motor implemented in this invention;

[0058] Figure 4 The waveforms of the stator current and harmonic current obtained by implementing the decoupling control strategy of this invention under steady-state conditions with a given rotational speed of 300 rpm and a load torque of 4 N·m are shown. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] Example 1

[0061] See Figure 1 The present invention provides a technical solution for a decoupling modeling method for a multi-channel permanent magnet synchronous motor, comprising the following steps:

[0062] S1: Establish a mathematical model of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system, including voltage equation, flux linkage equation and torque equation;

[0063] S2: A decoupling matrix H2 is proposed for the coupled inductance matrix L in the voltage equation of a dual-channel permanent magnet synchronous motor.

[0064] S3: Apply the decoupling matrix H2 to the mathematical model of the dual-channel permanent magnet synchronous motor to obtain the mathematical model of the decoupling of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system;

[0065] S4: The proposed decoupling matrix H2 is extended to multi-channel motors, and a decoupling matrix H2 based on multi-channel permanent magnet synchronous motors is proposed. n .

[0066] In step S1, the dual-channel permanent magnet synchronous motor refers to a motor in which the A, B, and C phase windings of a traditional six-phase motor form the first channel, and the U, V, and W phase windings form the second channel. Therefore, a dual-channel permanent magnet synchronous motor is constructed. The mathematical model of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system is as follows:

[0067] (1)

[0068] Among them, u dq = [u d1 u q1 u d2 u q2 ] T R = diag[r rrr],i dq = [i d1 i q1 i d2 i q2 ] T , ψ dq =[ψ d1 ψ q1 ψ d2 ψ q2 ] T In the formula, u d1 u q1 u d2 u q2 Let r be the stator voltage, r be the stator resistance, and i be the stator voltage. d1 i q1 i d2 i q2 For stator current, ψ d1 ψ q1 ψ d2 ψ q2 For the motor flux linkage, ω e The electric angular velocity of the motor;

[0069] The coefficient matrix J is represented as:

[0070] (2)

[0071] The flux linkage equation is expressed as:

[0072] (3)

[0073] Where λ = [1 0 1 0] T ψf is the flux linkage of the permanent magnet;

[0074] The coupled inductance matrix L is represented as:

[0075] (4)

[0076] In the formula, L d L q These are the components of the motor inductance along the d-axis and q-axis, respectively. dd L qq For a dual-channel motor, the coupling inductor is used.

[0077] The torque equation is expressed as:

[0078] (5)

[0079] In the formula, T e p represents the electromagnetic torque of the motor. n This indicates the number of pole pairs of the motor.

[0080] In step S2, for the coupled inductance matrix L in the voltage equation of the dual-channel motor, a decoupling matrix H2 is expressed as:

[0081] (6)

[0082] The coupling inductance matrix L is orthogonally transformed using the decoupling matrix H2 to eliminate coupling terms in L, resulting in the diagonal inductance matrix L. * Represented as:

[0083] (7).

[0084] In step S3, the decoupling matrix H2 is applied to the mathematical model of the dual-channel motor in the synchronous rotating coordinate system, specifically as follows:

[0085] (8)

[0086] Among them, u DQ = [u D1 u Q1 u D2 u Q2 ] T i DQ = [iD1 i Q1 i D2 i Q2 ] T , ψ DQ = [ψ D1 ψ Q1 ψ D2 ψ Q2 ] T In the formula, u D1 u Q1 u D2 u Q2 To decouple the stator voltage, i D1 i Q1 i D2 i Q2 To decouple the stator current, ψ D1 ψ Q1 ψ D2 ψ Q2 To decouple the motor flux;

[0087] Transformed coefficient matrix J * Represented as:

[0088] (9)

[0089] The decoupled flux linkage equation is expressed as:

[0090] (10)

[0091] Specifically, λ * = [sqrt(2) 0 0 0] T ;

[0092] The torque equation, after decoupling, is expressed as:

[0093] (11)

[0094] In the formula, T E This represents the decoupled electromagnetic torque, thus obtaining the mathematical model of the dual-channel permanent magnet synchronous motor under the decoupling modeling method;

[0095] The current components of the proposed decoupling modeling method in the synchronous rotating coordinate system are as follows:

[0096] (12).

[0097] In step S4, the proposed decoupling matrix is ​​extended and applied to multi-channel motors, and a decoupling matrix H based on multi-channel permanent magnet synchronous motors is proposed. n Represented as:

[0098] (13)

[0099] Where n represents the number of channels, and takes the value n = 2k, k∈N * Specifically, H0 is represented as:

[0100] (14)

[0101] After decoupling, the electromagnetic torque of the multi-channel motor is the superposition of the torques from multiple channels, expressed as:

[0102] (15)

[0103] Among them, T k This represents the electromagnetic torque of the motor in each channel after decoupling.

[0104] Example 2

[0105] Based on Example 1, Figure 2 This is a schematic diagram illustrating the overall control of the decoupling modeling method of this invention, using a dual-channel permanent magnet synchronous motor as an example. The control strategy employs rotor-oriented vector control based on dual SVPWM. First, position information is acquired at the motor side for coordinate transformation, and speed and current information are acquired as the actual quantities for the outer and inner loops, respectively. The outer loop is the speed loop, and the inner loop is the current loop. Second, the decoupled channel current is controlled in a closed loop using a PI regulator to obtain the decoupled reference voltage. Third, the reference voltage in the synchronous rotating coordinate system is obtained through the inverse transformation of the decoupling matrix proposed in this invention. Finally, the mature SVPWM control strategy for three-phase motors is used to drive the modular inverter to output PWM signals for channel one and channel two, thereby driving the normal operation of the dual-channel permanent magnet synchronous motor. Figure 3 This is a schematic diagram of a 2kW dual-channel permanent magnet synchronous motor implemented in this invention, wherein the phase difference between the two channel windings is π / 6. Figure 4 To implement the decoupling control strategy of this invention under steady-state conditions of a given speed of 300 rpm and a load torque of 4 N·m on this motor, the stator current and harmonic current i of the channel were observed. x i y The experimental results waveform diagram. Where i A i U These are the phase currents of phase A in motor channel one and phase U in motor channel two, respectively. x i y The image shows the channel harmonic current extracted using a vector space decoupling strategy. It can be seen that the phase current has good sinusoidal properties, and the harmonic current can be effectively suppressed. The dual-channel motor system exhibits good steady-state performance under the decoupling control strategy, achieving the performance targets of the control system.

[0106] The following uses a four-channel motor as an example to further illustrate the multi-channel decoupling modeling matrix proposed in this invention. By forming a channel from every three phase windings in a traditional twelve-phase motor, a twelve-phase permanent magnet synchronous motor can be transformed into a four-channel permanent magnet synchronous motor. In the synchronous rotating coordinate system, the coupling inductance matrix L4 of the twelve-phase windings of the four-channel motor is expressed as:

[0107] (16)

[0108] Where the subscript 4 indicates that the number of channels is 4, i.e., n = 4. The novel four-channel decoupling matrix H4 proposed in this invention is constructed as follows:

[0109] (17)

[0110] Applying equation (16) to perform an orthogonal transformation on equation (15), the four-channel decoupled inductor matrix L*4 is obtained as follows:

[0111] (18)

[0112] Similarly, the decoupling matrix proposed in this invention can be extended to multi-channel motors. For the decoupling method between channels of multi-channel permanent magnet synchronous motors, the decoupling matrix of this invention is simple to construct, eliminating the tedious work of optimizing the regulator and is easy to implement. For the mathematical model of multi-channel motors in synchronous rotating coordinate system, the decoupling matrix of this invention is based on the modeling method of multi-d-q coordinate transformation, which is not limited by the type of motor winding, that is, it is independent of the phase difference between the windings of each channel, and can be applied to symmetrical or asymmetrical motors, improving the feasibility and applicability of the decoupling modeling method of this invention. For the coupling inductance matrix between channels of multi-channel motors, the decoupling matrix of this invention can orthogonally transform the off-diagonal inductance matrix into a diagonal inductance matrix, eliminating the mutual coupling between channels, which is beneficial for the independent channel control of multi-channel motor systems and has broad application prospects.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A decoupling modeling method for a multi-channel permanent magnet synchronous motor, characterized in that, Includes the following steps: S1: Establish a mathematical model of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system, including voltage equation, flux linkage equation and torque equation; S2: A decoupling matrix H2 is proposed for the coupled inductance matrix L in the voltage equation of a dual-channel permanent magnet synchronous motor. In step S2, for the coupled inductance matrix L in the voltage equation of the dual-channel motor, a decoupling matrix H2 is expressed as: (6)； The coupling inductance matrix L is orthogonally transformed using the decoupling matrix H2 to eliminate coupling terms in L, resulting in the diagonal inductance matrix L. * Represented as: (7)； The coupled inductance matrix L is represented as: (4)； In the formula, L d L q These are the components of the motor inductance along the d-axis and q-axis, respectively. dd L qq For a dual-channel motor, the coupling inductor is used. S3: Apply the decoupling matrix H2 to the mathematical model of the dual-channel permanent magnet synchronous motor to obtain the mathematical model of the decoupling of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system; S4: The proposed decoupling matrix H2 is extended to multi-channel motors, and a decoupling matrix H2 based on multi-channel permanent magnet synchronous motors is proposed. n ; In step S4, the proposed decoupling matrix is ​​extended and applied to multi-channel motors, and a decoupling matrix H based on multi-channel permanent magnet synchronous motors is proposed. n Represented as: (13)； Where n represents the number of channels, and takes the value n = 2k, k∈N * H0 is represented as: (14)； After decoupling, the electromagnetic torque of the multi-channel motor is the superposition of the torques from multiple channels, expressed as: (15)； Among them, T E p represents the decoupled electromagnetic torque. n T represents the number of pole pairs of the motor. k This represents the electromagnetic torque of the motor in each channel after decoupling.

2. The decoupling modeling method for a multi-channel permanent magnet synchronous motor according to claim 1, characterized in that, In step S1, the dual-channel permanent magnet synchronous motor refers to a motor in which the A, B, and C phase windings of a traditional six-phase motor form the first channel, and the U, V, and W phase windings form the second channel, thus forming a dual-channel permanent magnet synchronous motor. The mathematical model of the dual-channel permanent magnet synchronous motor in the synchronous rotating coordinate system is as follows: (1)； Among them, u dq = [u d1 u q1 u d2 u q2 ] T R = diag[rr rr], i dq = [i d1 i q1 i d2 i q2 ] T , ψ dq = [ψ d1 ψ q1 ψ d2 ψ q2 ] T In the formula, u d1 u q1 u d2 u q2 Let r be the stator voltage, r be the stator resistance, and i be the stator voltage. d1 i q1 i d2 i q2 For stator current, ψ d1 ψ q1 ψ d2 ψ q2 For the motor flux linkage, ω e The electric angular velocity of the motor; The coefficient matrix J is represented as: (2)； The flux linkage equation is expressed as: (3)； Where λ = [1 0 1 0] T , ψ f For permanent magnet flux linkage; The torque equation is expressed as: (5)； In the formula, T e p represents the electromagnetic torque of the motor. n This indicates the number of pole pairs of the motor.

3. The decoupling modeling method for a multi-channel permanent magnet synchronous motor according to claim 2, characterized in that, In step S3, the decoupling matrix H2 is applied to the mathematical model of the dual-channel motor in the synchronous rotating coordinate system, specifically as follows: (8)； Among them, u DQ = [u D1 u Q1 u D2 u Q2 ] T i DQ = [i D1 i Q1 i D2 i Q2 ] T , ψ DQ = [ψ D1 ψ Q1 ψ D2 ψ Q2 ] T In the formula, u D1 u Q1 u D2 u Q2 To decouple the stator voltage, i D1 i Q1 i D2 i Q2 To decouple the stator current, ψ D1 ψ Q1 ψ D2 ψ Q2 To decouple the motor flux; Transformed coefficient matrix J * Represented as: (9)； The decoupled flux linkage equation is expressed as: (10)； In the formula, λ * = [sqrt(2) 0 0 0] T ; The torque equation, after decoupling, is expressed as: (11)； In the formula, T E This represents the decoupled electromagnetic torque, thus obtaining the mathematical model of the dual-channel permanent magnet synchronous motor under the decoupling modeling method; The current components of the proposed decoupling modeling method in the synchronous rotating coordinate system are as follows: (12)。

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