Multi-mode double five-phase permanent magnet synchronous motor torque ripple suppression fault-tolerant control method

Abstract

The invention discloses a multi-mode double-five-phase permanent magnet synchronous motor torque ripple suppression fault-tolerant control method, which belongs to the technical field of multi-phase motor open-circuit fault fault-tolerant control, and comprises the following steps: establishing a mathematical model under rotor eccentricity and single-phase open-circuit fault, and analyzing flux linkage imbalance characteristics caused by rotor eccentricity; an unbalanced flux linkage component is introduced, the influence of rotor eccentricity on the torque is quantified, and a second harmonic component in torque pulsation is deduced; according to three different working modes of the motor, a second harmonic current injection instruction is deduced based on a torque ripple suppression target; calculating harmonic current parameters by measuring back electromotive force data in an off-line manner, and integrating the harmonic current parameters into a fault-tolerant control framework; a switching signal is generated by adopting carrier-based pulse width modulation, and torque ripple suppression under a fault is realized. According to the invention, the torque ripple under the combined action of rotor eccentricity and open-circuit fault is effectively inhibited, and the operation stability and reliability of the motor are improved.

Description

Technical Field

[0001] This invention belongs to the field of fault-tolerant control technology for open-circuit faults in multiphase motors, and specifically relates to a fault-tolerant control method for suppressing torque ripple in multi-mode dual five-phase permanent magnet synchronous motors. Background Technology

[0002] Multiphase permanent magnet synchronous motors have become a research hotspot due to their advantages such as high power density, high efficiency, and high reliability. Among them, the multi-mode dual five-phase permanent magnet synchronous motor can achieve multiple operating modes through the flexible combination of two sets of stator windings, further improving the system's flexibility and fault tolerance. However, this type of motor often uses a special hollow cup rotor structure, which makes it prone to rotor eccentricity faults during manufacturing, installation, or long-term operation.

[0003] Chinese Patent Publication No. CN115622466A discloses a method for single-phase open-circuit fault-tolerant control of a multi-mode dual five-phase permanent magnet motor. However, this method has drawbacks. Traditional five-phase permanent magnet motors require increased residual phase current to maintain torque during fault-tolerant faults, leading to a greater degree of fault severity. Furthermore, the amplitude of the residual phase current increases under high torque conditions during open-circuit faults, affecting motor reliability. Chinese Patent Publication No. CN113271048B discloses a five-phase permanent magnet fault-tolerant motor. This patent discloses an open-circuit unified fault-tolerant control method for a five-phase permanent magnet fault-tolerant motor vector and direct torque control drive system. However, existing multi-phase permanent magnet motor fault-tolerant control methods suffer from problems such as inconsistent switching frequencies, large torque and flux linkage ripple, and complex algorithms that are difficult to implement in engineering, failing to fundamentally simplify the controller algorithm and minimize the reconfiguration control system. Furthermore, rotor eccentricity disrupts the uniformity of the air gap magnetic field, causing back electromotive force waveform distortion and specific harmonics, leading to electromagnetic torque ripple and vibration noise. While such torque ripple is acceptable during healthy motor operation, when an open-circuit fault occurs and a traditional fault-tolerant control strategy is employed, the fault-tolerant current reconfigured to maintain a constant magnetomotive force interacts complexly with the magnetic field harmonics introduced by rotor eccentricity, potentially amplifying torque ripple, severely deteriorating post-fault operating performance, and threatening system safety.

[0004] Currently, research on fault-tolerant control for open-circuit faults in multiphase motors mainly focuses on how to suppress torque ripple through current reconstruction, or on optimizing copper losses based on this. However, most of these methods are based on the assumption of an ideal motor structure and do not fully consider the rotor eccentricity problem that is common in practice. Especially for complex objects with multiple operating modes, existing technologies lack effective solutions for the combined fault scenario of rotor eccentricity and open-circuit faults, and cannot fully utilize the multi-mode operating potential of the motor to achieve optimal torque smooth control. Summary of the Invention

[0005] The purpose of this invention is to address the problem of aggravated torque ripple in existing multi-mode dual five-phase permanent magnet synchronous motors under combined faults of rotor eccentricity and winding open circuit, caused by the interaction between traditional fault-tolerant control strategies and harmonics from the eccentric magnetic field. This invention aims to provide a control method that, by introducing the unbalanced flux linkage caused by rotor eccentricity, derives harmonic current injection commands applicable to different operating modes. This method can effectively suppress torque ripple caused by rotor eccentricity while achieving fault-tolerant operation under open circuit faults, thereby improving the motor's operational stability and reliability under complex fault conditions.

[0006] To achieve the technical objectives, the present invention adopts the following technical solution:

[0007] A multi-mode dual five-phase permanent magnet synchronous motor torque ripple suppression and fault-tolerant control method, the control method comprising the following specific steps:

[0008] Step S1: Establish a multi-mode dual five-phase permanent magnet synchronous motor rotor eccentricity fault model, analyze the influence of eccentricity on the air gap magnetic field, introduce unbalanced flux linkage components, and establish the rotor eccentricity state. Equations for shaft flux linkage, voltage, and torque;

[0009] Step S2: For a single-phase open-circuit fault occurring in the outer stator of the motor, use the orthogonal reduced-order Clarke transformation matrix; combine the eccentric fault model from step 1 to derive the flux linkage and torque equations after the fault, and identify the specific order torque pulsation introduced by rotor eccentricity that may be amplified after the fault.

[0010] Step S3, with the core objective of suppressing the specific order torque ripple identified in step S2, derives the harmonic current injection command expression for compensating the torque ripple for different fault-tolerant operating modes of the motor.

[0011] Step S4: The back electromotive force waveform of the motor under rotor eccentricity is measured offline in advance. The specific parameters of the motor required for the harmonic current injection command in step S3 are extracted by fast Fourier transform analysis.

[0012] Step S5: Detect the speed of the multi-mode dual five-phase permanent magnet synchronous motor as the motor speed feedback. , give the speed With feedback speed The motor speed error was obtained by comparison. The multi-mode dual five-phase permanent magnet synchronous motor is calculated based on the speed error using a PI controller. Total reference value of shaft current ;

[0013] Step S6, based on the total current obtained in step S5 The data is input into the current distribution calculation module. First, the harmonic current injection command in step S3 is determined. Then, based on the offline parameters obtained in step S4 and the parameters of the given mode... , Determine the amount of harmonic current injection required to suppress torque ripple, and finally determine the final current reference values ​​input to the outer stator and inner stator;

[0014] Step S7: Compare the feedback current component obtained by the current sensor with the given current component obtained in step S6, and send the error to the PI controller to obtain the given voltage signal in the synchronous rotating coordinate system.

[0015] Step S8: The given voltage signal in the obtained synchronous rotating orthogonal coordinate system is input into the CPWM module after coordinate transformation to obtain the switching signals of each phase. Then, the obtained switching signals are input into the inverter to control the motor, so as to realize the torque ripple suppression and fault-tolerant control of the multi-mode dual five-phase permanent magnet synchronous motor under the coexistence of rotor eccentricity and open circuit fault.

[0016] Furthermore, the introduction of unbalanced flux linkage components under rotor eccentricity in step S1 specifically involves:

[0017] Permanent magnet flux linkage vector expression:

[0018]

[0019] in, =2π / 5, ( () indicates the phase flux linkage of the outer stator winding. ( This indicates the change in phase flux linkage of the outer stator winding caused by rotor eccentricity. It is the fundamental flux linkage of the external stator. It refers to the rotor position;

[0020] The internal stator flux linkage imbalance is relatively small; the formula for the internal stator flux linkage is given below:

[0021]

[0022] in, ( () indicates the phase flux linkage of the outer stator winding. ( This indicates the change in the internal stator phase flux linkage caused by rotor eccentricity. It is the fundamental magnetic flux linkage of the inner stator.

[0023] Furthermore, in step S1, the rotor eccentricity state is established. The equations for shaft flux linkage, voltage, and torque are as follows:

[0024] The motor is transformed by a fifth-order Clarke matrix in the natural coordinate system. Transform to a stationary coordinate system:

[0025]

[0026] Park transformation matrix from stationary coordinate system to synchronous rotating coordinate system for:

[0027]

[0028] The flux linkage formula in the external stator synchronous reference coordinate system is as follows:

[0029]

[0030] in, =2π / 5; Indicates the outer stator winding Axial permanent magnet flux linkage Indicates the inner stator winding Axial permanent magnet flux linkage This indicates the magnitude of the change in the external stator flux linkage; The phase of the change in the external stator flux linkage; This represents the change in the amplitude of the fundamental flux linkage of the outer stator winding; Indicates the rotor position;

[0031] The shaft flux linkage and voltage model are represented as follows:

[0032]

[0033] in, Indicates the outer stator winding Axial magnetic flux, Indicates the inner stator winding Axial magnetic flux; Indicates the outer stator winding. Shaft self-inductance, Indicates the inner stator winding Shaft self-inductance, and = , = ; This indicates the outer stator winding. shaft current, Indicates the inner stator winding shaft current; It is the mutual inductance between the inner and outer stators; It is the excitation coefficient, which represents the ability of the excitation winding to influence the external air gap flux linkage;

[0034]

[0035] in, Indicates the outer stator winding shaft voltage, Indicates the inner stator winding Shaft voltage; This indicates the phase resistance of the external stator. This indicates the phase resistance of the inner stator; The electric angular velocity of the motor;

[0036] Solving for the electromagnetic torque of the motor using the magnetic co-energy method The formula is:

[0037]

[0038] in, It is the magnetic energy of the motor; It is the mechanical angle of the motor; Indicates the outer stator winding of the motor Axis current vector, Indicates the inner stator winding of the motor Axis current vector; This indicates the number of pole pairs in the external stator winding of the motor. This indicates the number of pole pairs in the stator windings of the motor. It is an electrical angle; Permanent magnets representing the outer stator winding Axial flux linkage vector, Permanent magnets representing the inner stator winding Axial flux linkage vector;

[0039] The torque formula can be simplified as follows:

[0040] .

[0041] Furthermore, the specific process of using the orthogonal reduced-order Clarke transformation matrix in step S2 is as follows:

[0042] Assuming an open-circuit fault occurs in phase A, the traditional fault-tolerant strategy aims to maintain the magnetomotive force unchanged before and after the fault. By introducing an adjustment factor, a reduced-order Clarke transform of the fundamental frequency space is obtained. for:

[0043]

[0044] The flux linkage equation in the two-phase stationary coordinate system after a phase A fault is expressed as:

[0045]

[0046]

[0047] in, =2π / 5; Indicates the outer stator winding Axial magnetic flux, Indicates the inner stator winding Axial magnetic flux; This represents the amplitude corresponding to the sum of the permanent magnet flux linkages of each phase of the external stator winding. This indicates the phase corresponding to the sum of the permanent magnet flux linkages of each phase of the outer stator winding. ( () represents the opposite potential of the outer stator winding. It represents electric angular velocity.

[0048] Furthermore, the specific process of deriving the flux linkage and torque equations after the fault in step S2 is as follows:

[0049] After the malfunction The flux linkage equation on the axis is transformed by the Park transformation matrix to... On the axis:

[0050]

[0051] Using the reduced-order transformation matrix of the fundamental space, the torque expression shown in the equation is transformed to the synchronous rotating coordinate system. In the axis, and set =0:

[0052]

[0053]

[0054] in, This represents the phase offset angle of the torque ripple component; This represents the superposition of harmonic components on the in-phase axis under eccentric normal operation and traditional fault-tolerant operation. This represents the superposition of harmonic components on the orthogonal axis between normal operation under eccentricity and traditional fault-tolerant operation. This represents the total amplitude of the synthesized signal. This represents the phase angle of the synthesized signal relative to the in-phase axis.

[0055] Furthermore, the specific process of step S3 is as follows:

[0056] Torque formula for single-phase open circuit Represented as:

[0057]

[0058] in, = , This is the excitation coefficient;

[0059] Based on the above torque formula, harmonic current The injection command is as follows:

[0060]

[0061] Among them, parameter values and The parameter values ​​differ in different modes.

[0062] Furthermore, the parameter values ​​under the different modes are specifically as follows:

[0063] In Mode 1, the parameter values ​​are as follows: =0, X=0;

[0064] In Mode 3, the parameter values ​​are as follows: =0, X=1;

[0065] In mode four, the parameter values ​​are as follows: =-1, X=0.

[0066] Furthermore, the specific process of step S4 is as follows:

[0067] The back electromotive force waveform of the motor under rotor eccentricity is measured offline in advance. Then, through fast Fourier transform analysis, the motor-specific parameters required for calculating the harmonic current injection command in step S3 are extracted. , , , , The corresponding formula is as follows:

[0068]

[0069] in, ( This indicates an unbalanced flux linkage in the outer stator winding caused by rotor eccentricity. ψ fi ( () indicates the amplitude of the phase flux linkage of the outer stator winding. This represents 1 / 5 of the sum of the unbalanced flux linkages in the outer stator windings;

[0070]

[0071]

[0072] in, ( () represents the opposite potential of the outer stator winding. Indicates electric angular velocity;

[0073] The parameters obtained from offline testing are substituted into the current injection command in step S3 to suppress torque pulsation in different operating modes of the motor.

[0074] Furthermore, the working logic of the current distribution calculation module in step S6 is as follows:

[0075] With the primary goal of suppressing torque ripple, the harmonic current injection command in step S3 is first determined, followed by the offline parameters obtained in step S4 and the parameters corresponding to the given mode. , Determine the amount of harmonic current injection required to suppress torque ripple; then, based on the total current... The outer stator and inner stator are allocated. The shaft current reference value is used as the final current reference value.

[0076] Furthermore, the coordinate transformation in step S8 specifically includes:

[0077] Synchronous Rotating Orthogonal Coordinate System The given voltage signal under the axis is transformed to the stationary coordinate system via inverse Park transform. The axis is then transformed to the natural coordinate system via inverse Clarke transformation; the CPWM module generates the switching signals for each phase through conventional carrier-based pulse width modulation. After the switching signals are input to the inverter, they control the on / off state of the inverter's power devices, thereby driving the multi-mode dual five-phase permanent magnet synchronous motor to run.

[0078] Compared with the prior art, the beneficial effects of the present invention are:

[0079] 1) The fault-tolerant control method for suppressing torque ripple in multi-mode dual five-phase permanent magnet synchronous motor proposed in this invention is the first to systematically propose a fault-tolerant control solution for the combined fault of "rotor eccentricity" and "open circuit fault" in multi-mode dual five-phase permanent magnet synchronous motor, which effectively solves the problem of torque ripple aggravation in the presence of eccentricity in traditional fault-tolerant control.

[0080] 2) The multi-mode dual five-phase permanent magnet synchronous motor torque ripple suppression fault-tolerant control method proposed in this invention accurately models the influence of rotor eccentricity by introducing unbalanced flux components, and derives targeted harmonic current injection commands based on this, which can achieve active compensation and precise suppression of specific order (mainly second order) torque ripple caused by eccentricity.

[0081] 3) The multi-mode dual five-phase permanent magnet synchronous motor torque ripple suppression fault-tolerant control method proposed in this invention uses a control strategy whose core compensation parameters are obtained through offline measurement and FFT analysis. This eliminates the need to introduce complex observers or adaptive algorithms in online control, does not change the original dual closed-loop fault-tolerant control framework, is easy to implement in engineering applications on existing digital controllers, and has strong robustness. Attached Figure Description

[0082] Figure 1 The overall control block diagram of the fault-tolerant control method for a multi-mode dual five-phase permanent magnet synchronous motor under a combined fault of rotor eccentricity and single-phase open circuit;

[0083] Figure 2 The waveforms of the back electromotive force of the inner and outer stators are measured when the motor speed is 100 r / min.

[0084] Figure 3 The harmonic spectrum diagram corresponding to the opposite electromotive force of the inner and outer stators when the motor speed is 100 r / min;

[0085] Figure 4 The current and torque waveforms of the motor in mode one operation when there is an open circuit fault in phase A;

[0086] Figure 5 The current and torque waveforms of the motor in mode three operation when there is an open circuit fault in phase A;

[0087] Figure 6 The waveforms of current and torque of the motor when it is operating in mode four under an open-circuit fault in phase A. Detailed Implementation

[0088] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art can fully understand the invention even without these detailed descriptions. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail. To make the objectives, technical solutions, and advantages of the invention clearer, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0089] Figure 1 This paper presents the overall control block diagram of a fault-tolerant control method for a multi-mode dual five-phase permanent magnet synchronous motor under a combined fault of rotor eccentricity and single-phase open circuit. The specific implementation steps of this method are described in detail below with reference to the control block diagram:

[0090] A multi-mode dual five-phase permanent magnet synchronous motor torque ripple suppression fault-tolerant control method includes the following steps:

[0091] Step S1: Establish a multi-mode dual five-phase permanent magnet synchronous motor rotor eccentricity fault model, analyze the influence of eccentricity on the air gap magnetic field, introduce unbalanced flux linkage components, and establish the rotor eccentricity state. Equations for shaft flux linkage, voltage, and torque;

[0092] The expression for the permanent magnet flux linkage vector is obtained by introducing unbalanced flux linkage under rotor eccentricity:

[0093]

[0094] in, =2π / 5, ( () indicates the phase flux linkage of the outer stator winding. ( This indicates the change in phase flux linkage of the outer stator winding caused by rotor eccentricity. It is the fundamental flux linkage of the external stator. It refers to the rotor position;

[0095] The internal stator flux linkage imbalance is relatively small; the formula for the internal stator flux linkage is given below:

[0096]

[0097] in, ( () indicates the phase flux linkage of the outer stator winding. ( This indicates the change in the internal stator phase flux linkage caused by rotor eccentricity. It is the fundamental magnetic flux linkage of the inner stator.

[0098] The motor is transformed by a fifth-order Clarke matrix in the natural coordinate system. Transform to a stationary coordinate system:

[0099]

[0100] Park transformation matrix from stationary coordinate system to synchronous rotating coordinate system for:

[0101]

[0102] The flux linkage formula in the external stator synchronous reference coordinate system is as follows:

[0103]

[0104] in, =2π / 5; Indicates the outer stator winding Axial permanent magnet flux linkage Indicates the inner stator winding Axial permanent magnet flux linkage This indicates the magnitude of the change in the external stator flux linkage; The phase of the change in the external stator flux linkage; This represents the change in the amplitude of the fundamental flux linkage of the outer stator winding; Indicates the rotor position;

[0105] The shaft flux linkage and voltage model are represented as follows:

[0106]

[0107] in, Indicates the outer stator winding Axial magnetic flux, Indicates the inner stator winding Axial magnetic flux; Indicates the outer stator winding. Shaft self-inductance, Indicates the inner stator winding Shaft self-inductance, and = , = ; This indicates the outer stator winding. shaft current, Indicates the inner stator winding shaft current; It is the mutual inductance between the inner and outer stators; It is the excitation coefficient, which represents the ability of the excitation winding to influence the external air gap flux linkage;

[0108]

[0109] in, Indicates the outer stator winding shaft voltage, Indicates the inner stator winding Shaft voltage; This indicates the phase resistance of the external stator. This indicates the phase resistance of the inner stator; The electric angular velocity of the motor;

[0110] Solving for the electromagnetic torque of the motor using the magnetic co-energy method The formula is:

[0111]

[0112] in, It is the magnetic energy of the motor; It is the mechanical angle of the motor; Indicates the outer stator winding of the motor Axis current vector, Indicates the inner stator winding of the motor Axis current vector; This indicates the number of pole pairs in the external stator winding of the motor. This indicates the number of pole pairs in the stator windings of the motor. It is an electrical angle; Permanent magnets representing the outer stator winding Axial flux linkage vector, Permanent magnets representing the inner stator winding Axial flux linkage vector;

[0113] The torque formula can be simplified as follows:

[0114] .

[0115] Step S2: For a single-phase open-circuit fault occurring in the outer stator of the motor, use an orthogonal reduced-order Clarke transformation matrix; combine the eccentric fault model from step S1 to derive the flux linkage and torque equations after the fault, and identify the specific order torque pulsation introduced by rotor eccentricity that may be amplified after the fault.

[0116] Assuming an open-circuit fault occurs in phase A, the traditional fault-tolerant strategy aims to maintain the magnetomotive force unchanged before and after the fault. By introducing an adjustment factor, a reduced-order Clarke transform of the fundamental frequency space is obtained. for:

[0117]

[0118] The flux linkage equation in the two-phase stationary coordinate system after a phase A fault is expressed as:

[0119]

[0120]

[0121] in, =2π / 5; Indicates the outer stator winding Axial magnetic flux, Indicates the inner stator winding Axial magnetic flux; This represents the amplitude corresponding to the sum of the permanent magnet flux linkages of each phase of the external stator winding. This indicates the phase corresponding to the sum of the permanent magnet flux linkages of each phase of the outer stator winding. ( () represents the opposite potential of the outer stator winding. It represents electric angular velocity.

[0122] After the malfunction The flux linkage equation on the axis is transformed by the Park transformation matrix to... On the axis:

[0123]

[0124] Using the reduced-order transformation matrix of the fundamental space, the torque expression shown in the equation is transformed to the synchronous rotating coordinate system. In the axis, and set =0:

[0125]

[0126]

[0127] in, This represents the phase offset angle of the torque ripple component; This represents the superposition of harmonic components on the in-phase axis under eccentric normal operation and traditional fault-tolerant operation. This represents the superposition of harmonic components on the orthogonal axis between normal operation under eccentricity and traditional fault-tolerant operation. This represents the total amplitude of the synthesized signal. This represents the phase angle of the synthesized signal relative to the in-phase axis.

[0128] Step S3, with the core objective of suppressing the specific order torque ripple identified in step S2, derives the harmonic current injection command expression for compensating the torque ripple for different fault-tolerant operating modes of the motor.

[0129] Torque formula for single-phase open circuit Represented as:

[0130]

[0131] in, = , This is the excitation coefficient;

[0132] Based on the above torque formula, harmonic current The injection command is as follows:

[0133]

[0134] Among them, parameter values and The parameter values ​​differ in different modes, and the specific parameter values ​​in different modes are as follows:

[0135] In Mode 1, the parameter values ​​are as follows: =0, X=0;

[0136] In Mode 3, the parameter values ​​are as follows: =0, X=1;

[0137] In mode four, the parameter values ​​are as follows: =-1, X=0.

[0138] Step S4: The back electromotive force waveform of the motor under rotor eccentricity is measured offline in advance. The specific parameters of the motor required for the harmonic current injection command in step S3 are extracted by fast Fourier transform analysis.

[0139] The back electromotive force waveform of the motor under rotor eccentricity is measured offline in advance. Then, through fast Fourier transform analysis, the motor-specific parameters required for calculating the harmonic current injection command in step S3 are extracted. , , , , The corresponding formula is as follows:

[0140]

[0141] in, ( This indicates an unbalanced flux linkage in the outer stator winding caused by rotor eccentricity. ψ fi ( () indicates the amplitude of the phase flux linkage of the outer stator winding. This represents 1 / 5 of the sum of the unbalanced flux linkages in the outer stator windings;

[0142]

[0143]

[0144] in, ( () represents the opposite potential of the outer stator winding. Indicates electric angular velocity;

[0145] The parameters obtained from offline testing are substituted into the current injection command in step S3 to suppress torque pulsation in different operating modes of the motor.

[0146] Step S5: Detect the speed of the multi-mode dual five-phase permanent magnet synchronous motor as the motor speed feedback. , give the speed With feedback speed The motor speed error was obtained by comparison. The multi-mode dual five-phase permanent magnet synchronous motor is calculated based on the speed error using a PI controller. Total reference value of shaft current ;

[0147] Step S6, based on the total current obtained in step S5 The data is input into the current distribution calculation module. First, the harmonic current injection command in step S3 is determined. Then, based on the offline parameters obtained in step S4 and the parameters of the given mode... , Determine the amount of harmonic current injection required to suppress torque ripple, and finally determine the final current reference values ​​input to the outer stator and inner stator;

[0148] The working logic of the current distribution calculation module in step S6 is as follows:

[0149] With the primary goal of suppressing torque ripple, the harmonic current injection command in step S3 is first determined, followed by the offline parameters obtained in step S4 and the parameters corresponding to the given mode. , Determine the amount of harmonic current injection required to suppress torque ripple; then, based on the total current... The outer stator and inner stator are allocated. The shaft current reference value is used as the final current reference value.

[0150] Step S7: Compare the feedback current component obtained by the current sensor with the given current component obtained in step 6, and send the error to the PI controller to obtain the given voltage signal in the synchronous rotating coordinate system.

[0151] Step S8: The given voltage signal in the synchronous rotating orthogonal coordinate system is transformed and then input into the CPWM module to obtain the switching signals of each phase. The obtained switching signals are then input into the inverter to control the motor, thereby realizing the torque ripple suppression and fault-tolerant control of the multi-mode dual five-phase permanent magnet synchronous motor under the coexistence of rotor eccentricity and open circuit fault.

[0152] The coordinate transformation in step S8 is specifically as follows:

[0153] Synchronous Rotating Orthogonal Coordinate System The given voltage signal under the axis is transformed to the stationary coordinate system via inverse Park transform. The axis is then transformed to the natural coordinate system via inverse Clarke transformation; the CPWM module generates the switching signals for each phase through conventional carrier-based pulse width modulation. After the switching signals are input to the inverter, they control the on / off state of the inverter's power devices, thereby driving the multi-mode dual five-phase permanent magnet synchronous motor to run.

[0154] Figure 2 The image shows the waveforms of the back electromotive force of the inner and outer stators measured at a motor speed of 100 r / min. Figure 3This is the harmonic spectrum diagram corresponding to the opposite electromotive force of the inner and outer stators when the motor speed is 100 r / min. Figure 4-6 The motor experienced an open-circuit fault in phase A. Fault-tolerant control was implemented based on modes 1, 3, and 4, with a torque of 3.2 N·m. During the three experiments, the motor experienced four operating states: normal operation, open-circuit fault, classic fault tolerance, and novel fault tolerance. The figures show the torque and current waveforms of the motor during these four processes. When the fault-tolerant control method used in this invention is employed, the reduction in torque ripple is significant.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for torque ripple suppression fault-tolerant control of a multi-mode dual five-phase permanent magnet synchronous motor, characterized in that, The control method comprises the following specific steps: Step S1, the rotor eccentric fault model of the multi-mode double five-phase permanent magnet synchronous motor is established, the influence of the eccentricity on the air gap magnetic field is analyzed, the unbalanced flux linkage component is introduced, and the shaft flux linkage, voltage and torque equations under the rotor eccentricity state are established. Step S2, for the single-phase open circuit fault of the motor outer stator, using the orthogonal reduced order Clarke transformation matrix; combining the eccentric fault model of step 1, the flux linkage and torque equation after the fault are derived, and the specific order torque pulsation introduced by the rotor eccentricity and possibly amplified after the fault is identified; Step S3, taking the suppression of the specific order torque pulsation identified in step S2 as the core target, for different fault-tolerant operation modes of the motor, the harmonic current injection instruction expression for compensating the torque pulsation is derived respectively; Step S4, the back-EMF waveform of the motor under the rotor eccentricity is measured offline, and the specific parameters required for the harmonic current injection instruction calculation in step S3 are extracted through fast Fourier transform analysis; Step S5, detecting the speed of the multi-mode dual five-phase permanent magnet synchronous motor as the speed feedback of the motor , the given speed is compared with the feedback speed to obtain the speed error of the motor ; a PI controller is adopted to calculate the total reference value of the shaft current of the multi-mode dual five-phase permanent magnet synchronous motor according to the speed error ; and the total reference value of the shaft current is sent to the current controller. Step S6, the total current obtained from step S5 is input into the current distribution calculation module, the harmonic current injection instruction of step S3 is first determined, then the harmonic current injection amount required to suppress torque ripple is determined based on the offline parameters obtained in step S4 and the parameters of the given mode 、 , and finally the final current reference values input to the outer stator and the inner stator are determined; Step S7, the feedback current component obtained by the current sensor is compared with the given current component obtained in step S6, and the error is sent into the PI controller to obtain the given voltage signal in the synchronous rotating coordinate system; Step S8, the given voltage signal in the obtained synchronous rotating orthogonal coordinate system is input into the CPWM module after coordinate transformation to obtain the switching signal of each phase, and then the obtained switching signal is input into the inverter to control the motor, realizing the torque pulsation suppression fault-tolerant control of the multi-mode double five-phase permanent magnet synchronous motor under the coexistence of rotor eccentricity and open circuit fault.

2. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 1, characterized in that, The unbalanced flux linkage component introduced under the rotor eccentricity in step S1 is specifically: Permanent magnet flux linkage vector expression: in, =2π / 5, ( () indicates the phase flux linkage of the outer stator winding. ( This indicates the change in phase flux linkage of the outer stator winding caused by rotor eccentricity. It is the fundamental flux linkage of the external stator. It refers to the rotor position; The inner stator flux linkage is less unbalanced, and the inner stator flux linkage formula is given: wherein, represents the outer stator winding phase flux linkage, represents the inner stator phase flux linkage variation amount caused by the rotor eccentricity, is the inner stator fundamental flux linkage.​​ 3. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 2, characterized in that, The step S1 establishes the rotor eccentricity state under The axis flux linkage, voltage and torque equation are specifically: The electric machine is transformed into the stationary coordinate system by a fifth order Clarke transformation matrix into the stationary coordinate system: Park transformation matrix from stationary to synchronous rotating coordinate system is: The flux linkage formula in the outer stator synchronous reference coordinate system is as follows: wherein = 2π / 5; denotes the amplitude of the outer stator winding fundamental flux linkage axis permanent magnet flux linkage, denotes the amplitude of the inner stator winding fundamental flux linkage axis permanent magnet flux linkage, denotes the amplitude of the outer stator flux linkage variation; denotes the phase of the outer stator flux linkage variation; denotes the variation of the outer stator winding fundamental flux linkage amplitude; denotes the rotor position; The shaft flux and voltage model is represented as: wherein represents the axis flux of the outer stator winding, represents the axis flux of the inner stator winding; represents the axis self-inductance of the outer stator winding, represents the axis self-inductance of the inner stator winding, and represents the axis current of the outer stator winding, represents the axis current of the inner stator winding; is the mutual inductance of the inner and outer stator; is the excitation coefficient, which represents the ability of the excitation winding to influence the outer air-gap flux.​​​​ wherein represents the axis voltage of the outer stator winding represents the axis voltage of the inner stator winding represents the axis voltage of the inner stator winding represents the axis voltage of the inner stator winding represents the phase resistance of the outer stator represents the phase resistance of the inner stator is the electrical angular velocity of the motor According to the magnetic co-energy method, the formula for solving the electromagnetic torque of a motor is: T = 1 / 2 * (Ld - Lq) * Id * Iq wherein, is the magnetic co-energy of the electric machine; is the mechanical angle of the electric machine; denotes the axis current vector of the outer stator winding of the electric machine, denotes the axis current vector of the inner stator winding of the electric machine; denotes the number of pole pairs of the outer stator winding of the electric machine, denotes the number of pole pairs of the inner stator winding of the electric machine; is the electrical angle; denotes the permanent magnet flux linkage vector of the outer stator winding, denotes the permanent magnet flux linkage vector of the inner stator winding; The torque formula is simplified as: 。 4. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 3, characterized in that, The specific process of using the orthogonal reduced order Clarke transformation matrix in step S2 is as follows: Assuming open-circuit fault occurs in phase A, the traditional fault-tolerant strategy takes the invariance of the pre-fault and post-fault magnetomotive force as the target, introduces a regulation factor, and obtains the reduced-order Clarke transformation in the fundamental space is The A-phase fault two-phase static coordinate system flux linkage equation is expressed as: wherein = 2p / 5; denotes the axial flux of the outer stator winding, denotes the axial flux of the inner stator winding; denotes the amplitude of the sum of the permanent magnet fluxes per phase of the outer stator winding, denotes the phase of the sum of the permanent magnet fluxes per phase of the outer stator winding, denotes the phase voltage of the outer stator winding, denotes the electrical angular velocity.​ 5. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 4, characterized in that, The specific process of deriving the flux linkage and torque equation after the fault in step S2 is as follows: post-fault The flux linkage equations on the axis are transformed to the on the axis: The torque expression shown in the formula is transformed to the synchronous rotating coordinate system by using the reduced order transformation matrix of the fundamental space In the shaft, and set =0: wherein denotes the phase shift angle of the torque ripple component; denotes the superimposed component of the normal operation and the conventional fault-tolerant operation harmonic components in the in-phase axis under eccentricity, denotes the superimposed component of the normal operation and the conventional fault-tolerant operation harmonic components in the quadrature axis under eccentricity; denotes the total signal amplitude after synthesis, denotes the phase angle of the synthesized signal relative to the in-phase axis.

6. The method according to claim 5, wherein The specific process of step S3 is as follows: Torque formula for single phase open circuit is expressed as: wherein = 0.5 , is the excitation coefficient; Based on the above torque formula, the harmonic current The injection command is as follows: wherein the parameter values and The parameter values are different in different modes.

7. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 6, characterized in that, The parameter values under different modes are as follows: In the mode one state, the parameter values are specifically: = 0, X = 0; In the mode three state, the parameter values are specifically: = 0, X = 1; In the mode four state, the parameter values are specifically: = -1, X = 0.

8. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 7, characterized in that, The specific process of step S4 is as follows: By offline way, the back electromotive force waveform of the motor under the rotor eccentricity is measured in advance, and the motor specific parameters required for the harmonic current injection instruction calculation in step S3 are extracted through fast Fourier transform analysis , , , , , the corresponding formula is as follows: wherein represents the sum of the unbalanced flux linkages of the outer stator winding due to the rotor eccentricity, fi represents the amplitude of the phase flux linkage of the outer stator winding, represents 1 / 5 of the sum of the unbalanced flux linkages of the outer stator winding.​​​ wherein represents the opposite electrical potential of the outer stator winding, represents the electrical angular velocity;​ According to the parameters obtained by offline testing, the current injection instruction in step S3 is substituted, so that the motor can suppress the torque pulsation under different operation modes.

9. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method according to claim 8, characterized in that, The working logic of the current distribution calculation module in step S6 is as follows: With the primary goal of suppressing torque ripple, the harmonic current injection command in step S3 is first determined, followed by the offline parameters obtained in step S4 and the parameters corresponding to the given mode. , Determine the amount of harmonic current injection required to suppress torque ripple; then, based on the total current... The outer stator and inner stator are allocated. The shaft current reference value is used as the final current reference value.

10. The multi-mode dual five-phase permanent magnet synchronous motor torque ripple mitigation fault-tolerant control method of claim 9, wherein, The coordinate transformation in step S8 is as follows: Synchronous rotating orthogonal coordinate system The given voltage signal under the axis is converted to the stationary coordinate system through inverse Park transformation The axis, and then converted to the natural coordinate system through inverse Clarke transformation; the CPWM module generates each phase switching signal through the conventional carrier-based pulse width modulation method, and the switching signal is input to the inverter to control the on-off of the power device of the inverter, thereby driving the multi-mode dual five-phase permanent magnet synchronous motor to operate.

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