Diagnosis-free adaptive fault-tolerant control method and system under open-circuit fault of six-phase permanent magnet synchronous motor

Abstract

The invention relates to the technical field of permanent magnet synchronous motor control, in particular to a diagnosis-free adaptive fault-tolerant control method and system for a six-phase permanent magnet synchronous motor under an open-circuit fault, and discloses the following steps: S1, converting the voltage and current of the six-phase permanent magnet synchronous motor from a three-phase static coordinate system to a two-phase static coordinate system through Clark conversion, voltage and current in the two-phase static coordinate system are converted into a two-phase synchronous rotating coordinate system through Park conversion; s2, acquiring a current relation between q-axis current of the six-phase permanent magnet synchronous motor and the two-phase static coordinate system according to the two-phase synchronous rotating coordinate system, and further acquiring two-phase static coordinate system reference current for realizing fault tolerance under an open-circuit fault; and S3, optimizing the control signal of the reference current through a phase-locked loop of a second-order generalized integrator. According to the method, diagnosis-free adaptive fault-tolerant control under the open-circuit fault of the six-phase permanent magnet synchronous motor can be realized, and the problems of misdiagnosis and time delay are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motor control, and in particular to a diagnosis-free adaptive fault-tolerant control method and system for a six-phase permanent magnet synchronous motor under an open-circuit fault. Background Art

[0002] With the continuous development of modern industry, motors, as the core driving components of various equipment, have increasingly higher performance and reliability requirements. Among many types of motors, six-phase permanent magnet synchronous motors have gradually attracted widespread attention and application due to their unique structure and performance characteristics. It has shown superior characteristics over traditional three-phase motors in many fields, providing new solutions for the development of high-performance drive systems.

[0003] Although six-phase permanent magnet synchronous motors are widely used in industrial applications due to their high efficiency, high power density and high reliability, in actual operation, the motor may experience a phase failure due to various reasons (such as insulation aging, mechanical wear, etc.), which will seriously affect the performance and life of the motor. Traditional six-phase permanent magnet synchronous motors must be diagnosed before fault tolerance, which may lead to misdiagnosis and delay problems. Summary of the invention

[0004] The purpose of the present invention is to provide a diagnosis-free adaptive fault-tolerant control method and system for a six-phase permanent magnet synchronous motor under an open circuit fault, which solves the inherent idea that the traditional six-phase permanent magnet synchronous motor must be diagnosed before fault tolerance. The present invention fundamentally avoids the misdiagnosis and delay problems when introducing fault-tolerant control without using the diagnosis process. The proposed diagnosis-free self-fault-tolerant scheme can generally be applied to single-phase open circuit faults and multi-phase open circuit faults in multi-phase motor drivers. Moreover, under different open circuit fault conditions, the motor model, modulation strategy, and control framework do not need to be changed.

[0005] To achieve the above object, the present invention provides the following technical solution: a diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault, comprising the following steps:

[0006] S1. Obtain the voltage and current of the six-phase permanent magnet synchronous motor under an open circuit fault, transform the voltage and current of the six-phase permanent magnet synchronous motor from a three-phase stationary coordinate system to a two-phase stationary coordinate system through Clark transformation, and transform the voltage and current in the two-phase stationary coordinate system to a two-phase synchronous rotating coordinate system through Park transformation;

[0007] The voltage equation of the six-phase permanent magnet synchronous motor in the two-phase synchronous rotating coordinate system is:

[0008]

[0009] The voltage equation of the six-phase permanent magnet synchronous motor in the two-phase stationary coordinate system is:

[0010]

[0011] Among them, U d , U q is the stator voltage of the two-phase synchronous rotating coordinate system, U x , U y is the stator voltage of the two-phase stationary coordinate system, i d 、i q is the stator current of the two-phase synchronous rotating coordinate system, i x 、i y is the stator current of the two-phase stationary coordinate system, R is the stator resistance, L d , L q is the inductance in the dq coordinate system, L z is the leakage inductance, ω e is the electrical angular velocity of the motor, ψ f is the rotor flux.

[0012] S2. Obtain the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the current of the two-phase stationary coordinate system according to the two-phase synchronous rotating coordinate system, and then obtain the reference current of the two-phase stationary coordinate system for achieving fault tolerance under an open circuit fault;

[0013] S3, optimizing the control signal of the reference current through the phase-locked loop of the second-order generalized integrator, obtaining the control signal of the new reference current, so that the actual value of the current in the two-phase stationary coordinate system under the open circuit fault continuously replaces the value of the reference current, and the actual value of the current in the two-phase stationary coordinate system under the open circuit fault gradually converges to the ideal value of the current;

[0014] S4, suppressing the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under the open circuit fault by improving the repetitive controller, and updating the current of the healthy phase under the open circuit fault by the variable gain PI controller according to the control signal of the new reference current to obtain an updated current reference value;

[0015] S5. Generate a six-phase voltage reference signal from the updated current reference value through a space vector modulation module, and drive the motor to run smoothly based on the six-phase voltage reference signal.

[0016] The present invention is further configured such that the formula for converting the voltage and current of the six-phase permanent magnet synchronous motor from a three-phase stationary coordinate system to a two-phase stationary coordinate system through Clark transformation is:

[0017]

[0018] Among them, i A 、i B 、i C and i U 、i V 、iW Represent ABC three-phase current and UVW three-phase current respectively, i α1 、i β1 and i α2 、i β2 Represent two independent α-β coordinate systems respectively.

[0019] The present invention is further configured that the step of converting the voltage and current in the two-phase stationary coordinate system to the two-phase synchronous rotating coordinate system by Park transformation comprises:

[0020] Combining the two independent α-β coordinate systems with the electromagnetic torque equation of the six-phase permanent magnet synchronous motor, the current in the two-phase synchronous rotating coordinate system is obtained:

[0021]

[0022] Among them, i α1 、i β1 and i α2 、i β2 Represent the current in two independent α-β coordinate systems, i α 、i β and i x 、i y Represents the current in the two-phase synchronous rotating coordinate system;

[0023] The electromagnetic torque equation of the six-phase permanent magnet synchronous motor is:

[0024] T e =3p n i q [i d (L d -L q )+ψ f ];

[0025] Among them, T e is the electromagnetic torque, p n is the pole pair number, L d , L q is the inductance in the two-phase synchronous rotating coordinate system, ψ f is the rotor flux, i d 、i q is the stator current in the two-phase synchronous rotating coordinate system.

[0026] The present invention is further configured that the step of obtaining the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the current of the two-phase stationary coordinate system according to the two-phase synchronous rotating coordinate system includes:

[0027] Combining the two-phase synchronous rotating coordinate system with the motion equation of the six-phase permanent magnet synchronous motor, the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the two-phase stationary coordinate system is obtained, and the formula is:

[0028]

[0029] The motion equation of the six-phase permanent magnet synchronous motor is:

[0030]

[0031] Among them, p n is the pole pair number, T e is the electromagnetic torque, T L is the load torque, B is the damping coefficient, J is the moment of inertia, and ω is the mechanical angular velocity.

[0032] The present invention is further configured that the step of optimizing the reference current through a phase-locked loop of a second-order generalized integrator comprises:

[0033] S1, obtain input signal;

[0034] S2, decomposes the input signal into a pair of orthogonal signals;

[0035] S3, obtaining and comparing the quadrature signal with the control signal of the reference current to generate a phase error signal;

[0036] S4, filtering and smoothing the phase error signal to obtain a new reference current control signal.

[0037] Assume that the input signal u g is a pure sinusoidal signal:

[0038] u g =U gm cosθ g ;

[0039] Among them, U gm ,θ g for u g The amplitude and phase of the signal. According to the Mason formula, the transfer functions of the orthogonal signal from ug to the output of the second-order generalized integrator are:

[0040]

[0041] The expression of Park transformation is:

[0042]

[0043] Combining the above formulas, we can get:

[0044]

[0045] The present invention is further configured such that the improved repetitive controller includes a periodic signal generator, a controller gain, a low-pass filter and a phase advance compensation link.

[0046] The present invention is further configured that the steps of suppressing the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under an open circuit fault by improving the repetitive controller include:

[0047] S1, inputs the error signal into the internal model to generate a signal with the same frequency and phase characteristics as the controlled periodic signal;

[0048] S2, filtering the signal generated by the internal model through a low-pass filter to remove high-frequency interference signals;

[0049] S3, performing phase compensation on the filtered signal through a phase advance compensation link to compensate for control and transmission delays;

[0050] S4, adjusting the signal amplitude after the above processing by the controller gain to adjust the system error convergence rate;

[0051] S5, outputting the final processed signal as a control signal to adjust the actual output of the system;

[0052] S6, compare the actual output of the system with the expected output again to form a closed-loop control;

[0053] S7, converts the repetitive controller in the continuous domain into the discrete domain for implementation in a digital control system.

[0054] The transfer function of the improved repetitive controller is:

[0055]

[0056] Where Grc(s) is the periodic signal generator, T0 is the fundamental signal frequency, krc is the controller gain, which is used to adjust the system error convergence rate, Q(s) is the low-pass filter, Q(jω)≤1, and its function is to filter out the high-frequency interference signal in the system; sTc It is the phase advance compensation link, which is used to effectively compensate for the control and transmission delay of the entire system. sTc The introduction of can improve the dynamic response speed of the system and enhance the stability of the system;

[0057] Let z = e sTs The transfer function can be discretized as:

[0058]

[0059] The present invention is further configured such that the mathematical formula of the variable gain PI controller is:

[0060]

[0061] Where: e(t) is the input of the controller, y(t) is the output of the variable gain PI controller, K p is the proportional gain, K i is the integral gain.

[0062] The present invention is further configured such that the switching formula of the proportional gain is:

[0063]

[0064] Among them, K p Represents the proportional gain, which changes with time t. <T s When

[0065] K pi Increase to K pf , where n is the exponential factor, T s is the switching time, when t ≥ T s When the proportional gain is fixed at

[0066] K pf ;

[0067] The switching formula of integral gain is:

[0068]

[0069] Among them, K i When t<T s It will gradually increase when t>T s When it is fixed as a constant, K if is the initial integral gain, K i is the integral gain;

[0070] The unit step response formula of the variable gain PI controller is:

[0071]

[0072] To determine the parameters of the variable gain PI controller, the following method is used for tuning: Assume n = l, and select a larger K to overcome load disturbances. if and an appropriate T s ; Determine K according to the principle of reducing speed overshoot pi and K pf ; If the speed overshoot cannot be effectively suppressed, then continuously adjust Ts and repeat the above steps until you are satisfied; if the requirement cannot be met by increasing Ts, then increase n until you are satisfied.

[0073] The present invention also discloses a diagnosis-free adaptive fault-tolerant control system for a six-phase permanent magnet synchronous motor under an open-circuit fault, comprising: a PI controller module, an improved repetitive controller module and a phase-locked loop based on a second-order generalized integrator;

[0074] A phase-locked loop based on a second-order generalized integrator is used to process and optimize the current in a two-phase stationary coordinate system;

[0075] The improved repetitive controller module is used for receiving the output from the second-order generalized integrator-based phase-locked loop and suppressing the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under the open circuit fault;

[0076] The PI controller module is used to output the updated compensated current.

[0077] The beneficial effects of this application are:

[0078] (1) An improved repetitive controller is designed. The traditional PI controller can effectively track DC signals, but is powerless for unconventional fault-tolerant currents. Repetitive control can effectively suppress interference signals and does not rely on the mathematical model of the control system. Therefore, repetitive control is very suitable for tracking periodic unconventional currents in fault-tolerant operation of dual three-phase motor systems.

[0079] (2) A variable gain PI controller was designed. The variable gain PI controller (VGPI) has the same steady-state performance as the general PI controller, but the variable gain PI has greater step damping than the general PI in the dynamic process, which can overcome the overshoot in the dynamic process and allow the permanent magnet synchronous motor to switch quickly and stably from the fault state to the fault-tolerant state.

[0080] (3) A phase-locked loop based on a second-order generalized integrator is designed. Under self-fault-tolerant control, the current reference value will be automatically adjusted according to the amplitude and phase angle of the actual current values ​​ix and iy in the two-phase stationary coordinate system obtained from the phase-locked loop based on the second-order generalized integrator. As the given current reference value in the two-phase stationary coordinate system is continuously replaced by the actual current, the reference value and actual value of the two-phase stationary coordinate system will gradually approach their ideal values ​​during the iteration process. Ultimately, the angle error and amplitude error between the actual current value and the ideal current value in the two-phase stationary coordinate system will be eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 This is a block diagram of the diagnosis-free self-fault-tolerant control of a six-phase permanent magnet synchronous motor;

[0082] Figure 2 To improve the block diagram of the repetitive controller;

[0083] Figure 3 It is the block diagram of the phase-locked loop based on the second-order generalized integrator;

[0084] Figure 4 It is the block diagram of the second-order generalized integrator structure;

[0085] Figure 5 This is the A-phase missing fault self-tolerant six-phase current waveform diagram without diagnosis;

[0086] Figure 6 This is the A-phase missing fault self-tolerance torque waveform diagram without diagnosis;

[0087] Figure 7 This is the speed waveform diagram of the A phase loss fault without diagnosis and self-fault tolerance.

[0088] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0089] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0090] The design idea of ​​the present invention is that fault diagnosis is regarded as a necessary prerequisite for fault-tolerant control, but the diagnostic process itself will have many adverse effects on the reliability of the motor drive system. It is possible that there are similar fault characteristics to the fault under study, which will cause the drive system to be misdiagnosed, thereby causing more serious damage to the motor drive system. Secondly, the diagnostic process usually takes a certain amount of time to obtain sufficient information to distinguish different fault implementations. Therefore, the time occupied by the diagnosis will delay the introduction of fault-tolerant control and increase the damage to the motor caused by fault operation. In response to this problem, the inherent idea of ​​"diagnosis first, fault tolerance later" can be jumped out, and a diagnosis-free self-fault-tolerant control strategy suitable for multiple types of faults can be designed with the help of the fault-tolerant ability of the six-phase permanent magnet synchronous motor drive system itself. First, the self-fault-tolerant mechanism of the dual three-phase permanent magnet synchronous motor drive system is deeply analyzed. Then, by optimizing the given mode of the current reference value, the suppressed self-fault-tolerant ability of the dual three-phase permanent magnet synchronous motor drive system is released, thereby realizing automatic fault tolerance for different faults.

[0091] Next, the present invention will be described in detail.

[0092] like Figure 1-Figure 7 As shown, the present application provides a diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault, comprising the following steps:

[0093] S1. Obtain the voltage and current of the six-phase permanent magnet synchronous motor under an open circuit fault, transform the voltage and current of the six-phase permanent magnet synchronous motor from a three-phase stationary coordinate system to a two-phase stationary coordinate system through Clark transformation, and transform the voltage and current in the two-phase stationary coordinate system to a two-phase synchronous rotating coordinate system through Park transformation;

[0094] The voltage equation of the six-phase permanent magnet synchronous motor in the two-phase synchronous rotating coordinate system is:

[0095]

[0096] The voltage equation of the six-phase permanent magnet synchronous motor in the two-phase stationary coordinate system is:

[0097]

[0098] Among them, U d , U q is the stator voltage of the two-phase synchronous rotating coordinate system, U x , U y is the stator voltage of the two-phase stationary coordinate system, i d 、i q is the stator current of the two-phase synchronous rotating coordinate system, i x 、i y is the stator current of the two-phase stationary coordinate system, R is the stator resistance, L d , L q is the inductance in the dq coordinate system, L z is the leakage inductance, ω e is the electrical angular velocity of the motor, ψ f is the rotor flux.

[0099] S2. Obtain the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the current of the two-phase stationary coordinate system according to the two-phase synchronous rotating coordinate system, and then obtain the reference current of the two-phase stationary coordinate system for achieving fault tolerance under an open circuit fault;

[0100] S3, optimizing the control signal of the reference current through the phase-locked loop of the second-order generalized integrator, obtaining the control signal of the new reference current, so that the actual value of the current in the two-phase stationary coordinate system under the open circuit fault continuously replaces the value of the reference current, and the actual value of the current in the two-phase stationary coordinate system under the open circuit fault gradually converges to the ideal value of the current;

[0101] S4, suppressing the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under the open circuit fault by improving the repetitive controller, and updating the current of the healthy phase under the open circuit fault by the variable gain PI controller according to the control signal of the new reference current to obtain an updated current reference value;

[0102] S5. Generate a six-phase voltage reference signal from the updated current reference value through a space vector modulation module, and drive the motor to run smoothly based on the six-phase voltage reference signal.

[0103] The formula for converting the voltage and current of a six-phase permanent magnet synchronous motor from a three-phase stationary coordinate system to a two-phase stationary coordinate system through Clark transformation is:

[0104]

[0105] Among them, i A 、i B 、i C and i U 、i V 、i W Represent ABC three-phase current and UVW three-phase current respectively, i α1 、i β1 and i α2 、i β2 Represent two independent α-β coordinate systems respectively.

[0106] The steps of converting the voltage and current in the two-phase stationary reference system to the two-phase synchronous rotating reference system by Park transformation include:

[0107] Combining the two independent α-β coordinate systems with the electromagnetic torque equation of the six-phase permanent magnet synchronous motor, the current in the two-phase synchronous rotating coordinate system is obtained:

[0108]

[0109] Among them, i α1 、i β1 and i α2 、i β2 Represent the current in two independent α-β coordinate systems, i α 、i β and i x 、i y Represents the current in the two-phase synchronous rotating coordinate system;

[0110] The electromagnetic torque equation of the six-phase permanent magnet synchronous motor is:

[0111] T e =3p n i q [i d (L d -L q )+ψ f ];

[0112] Among them, Te is the electromagnetic torque, pn is the number of pole pairs, Ld and Lq are the inductances in the two-phase synchronous rotating coordinate system, ψf is the rotor flux, and id and iq are the stator currents in the two-phase synchronous rotating coordinate system.

[0113] The steps of obtaining the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the current of the two-phase stationary coordinate system according to the two-phase synchronous rotating coordinate system include:

[0114] Combining the two-phase synchronous rotating coordinate system with the motion equation of the six-phase permanent magnet synchronous motor, the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the two-phase stationary coordinate system is obtained, and the formula is:

[0115]

[0116] The motion equation of the six-phase permanent magnet synchronous motor is:

[0117]

[0118] Among them, Te is the electromagnetic torque, TL is the load torque, B is the damping coefficient, J is the moment of inertia, and ω is the mechanical angular velocity.

[0119] Taking the A-phase fault as an example, the reference current under the current compensation fault-tolerant control is analyzed. Under the A-phase missing phase fault (iA=0), i*α1=0 can be obtained. In order to compensate for the missing i*α1=0, the dual coordinate system relationship can be obtained:

[0120]

[0121] Combining the above formulas, the relationship between the current in the decoupled coordinate system and the current in the dual coordinate system under fault conditions can be obtained:

[0122]

[0123] Then, the reference current of the harmonic subspace for achieving fault tolerance after phase A failure can be obtained:

[0124]

[0125] The steps to optimize the reference current through a second-order generalized integrator phase-locked loop include:

[0126] S1, obtain input signal;

[0127] S2, decomposes the input signal into a pair of orthogonal signals;

[0128] S3, obtaining and comparing the quadrature signal with the control signal of the reference current to generate a phase error signal;

[0129] S4, filtering and smoothing the phase error signal to obtain a new reference current control signal.

[0130] Assume that the input signal ug is a pure sinusoidal signal:

[0131] u g =U gm cosθ g ;

[0132] Among them, Ugm and qg are the amplitude and phase of ug. According to the Mason formula, the transfer functions of the orthogonal signals from ug to the output of the second-order generalized integrator are:

[0133]

[0134]

[0135] The expression of Park transformation is:

[0136]

[0137] Combining the above formula, we can get:

[0138]

[0139] The improved repetitive controller includes a periodic signal generator, a controller gain, a low-pass filter and a phase advance compensation link.

[0140] The steps of suppressing the harmonic components and periodic disturbance of the new reference current in the two-phase stationary reference system under the open circuit fault by improving the repetitive controller include:

[0141] S1, inputs the error signal into the internal model to generate a signal with the same frequency and phase characteristics as the controlled periodic signal;

[0142] S2, filtering the signal generated by the internal model through a low-pass filter to remove high-frequency interference signals;

[0143] S3, performing phase compensation on the filtered signal through a phase advance compensation link to compensate for control and transmission delays;

[0144] S4, adjusting the signal amplitude after the above processing by the controller gain to adjust the system error convergence rate;

[0145] S5, outputting the final processed signal as a control signal to adjust the actual output of the system;

[0146] S6, compare the actual output of the system with the expected output again to form a closed-loop control;

[0147] S7, converts the repetitive controller in the continuous domain into the discrete domain for implementation in a digital control system.

[0148] The transfer function of the improved repetitive controller is:

[0149]

[0150] Where Grc(s) is the periodic signal generator, T0 is the fundamental signal frequency, krc is the controller gain, which is used to adjust the system error convergence rate, Q(s) is the low-pass filter, Q(jω)≤1, and its function is to filter out the high-frequency interference signal in the system; sTcis the leading phase compensation link, and its function is to effectively compensate for the control and transmission delays of the entire system. The introduction of krc, Q(s), and e sTc can improve the dynamic response speed of the system and enhance the stability of the system;

[0151] Let z = e sTs The transfer function can be discretized as:

[0152]

[0153] The mathematical formula of the variable gain PI controller is:

[0154]

[0155] where: e(t) is the input of the controller, y(t) is the output of the variable gain PI controller, Kp is the proportional gain, and Ki is the integral gain.

[0156] The switching formula of the proportional gain is:

[0157]

[0158] where, Kp represents the proportional gain, which changes with time t. When t < Ts, the proportional gain gradually increases from Kpi to Kpf. Here, n is the exponential factor and Ts is the switching time. When t ≥ Ts, the proportional gain is fixed at Kpf;

[0159] The switching formula of the integral gain is:

[0160]

[0161] where, K i will gradually increase when t < Ts and then be fixed as a constant when t > Ts. K if is the initial integral gain, and K i is the integral gain;

[0162] The unit step response formula of the variable gain PI controller is:

[0163]

[0164] To determine the parameters of the variable gain PI controller, the following method is used for tuning: Assume n = 1. To overcome the load disturbance, select a relatively large K if and an appropriate T s ; Determine K pi and K pf according to the principle of reducing the speed overshoot.; If the speed overshoot cannot be effectively suppressed, then continuously adjust Ts and repeat the above steps until you are satisfied; if the requirement cannot be met by increasing Ts, then increase n until you are satisfied.

[0165] The present invention also discloses a diagnosis-free adaptive fault-tolerant control system for a six-phase permanent magnet synchronous motor under an open-circuit fault, comprising: a PI controller module (PI), an improved repetitive controller module (RC+PI) and a second-order generalized integrator-based phase-locked loop (SOGI-PLL);

[0166] A second-order generalized integrator-based phase-locked loop (SOGI-PLL) is used to process and optimize the current in the two-phase stationary reference frame;

[0167] An improved repetitive controller module (RC+PI) is used to receive the output from the second-order generalized integrator-based phase-locked loop (SOGI-PLL) and suppress the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under the open circuit fault;

[0168] The PI controller module (PI) is used to output the updated compensated current.

[0169] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media provided in this application and used in the embodiments may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0170] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0171] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent results or equivalent process changes made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault, characterized in that: The following steps are involved: S1. Obtain the voltage and current of the six-phase permanent magnet synchronous motor under an open circuit fault, transform the voltage and current of the six-phase permanent magnet synchronous motor from a three-phase stationary coordinate system to a two-phase stationary coordinate system through Clark transformation, and transform the voltage and current in the two-phase stationary coordinate system to a two-phase synchronous rotating coordinate system through Park transformation; S2. Obtain the relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the current of the two-phase stationary coordinate system according to the two-phase synchronous rotating coordinate system, and then obtain the reference current of the two-phase stationary coordinate system for achieving fault tolerance under an open circuit fault; S3, optimizing the control signal of the reference current through a phase-locked loop of a second-order generalized integrator to obtain a control signal of a new reference current, so that the actual value of the current in the two-phase stationary coordinate system under the open circuit fault continuously replaces the value of the reference current, and the actual value of the current in the two-phase stationary coordinate system under the open circuit fault gradually converges to the ideal value of the current; S4, suppressing the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under the open circuit fault by improving the repetitive controller, and updating the current of the healthy phase under the open circuit fault by the variable gain PI controller according to the control signal of the new reference current to obtain an updated current reference value; S5. Generate a six-phase voltage reference signal from the updated current reference value through a space vector modulation module, and drive the motor to run smoothly based on the six-phase voltage reference signal.

2. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 1 is characterized in that: The formula for converting the voltage and current of the six-phase permanent magnet synchronous motor from the three-phase stationary coordinate system to the two-phase stationary coordinate system through Clark transformation is: Among them, i A 、i B 、i C and i U 、i V 、i W Represents ABC three-phase current and UVW three-phase current respectively, i α1 、i β1 and i α2 、i β2 Represent two independent α-β coordinate systems respectively.

3. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 2 is characterized in that: The step of converting the voltage and current in the two-phase stationary coordinate system to the two-phase synchronous rotating coordinate system by Park transformation comprises: Combining the two independent α-β coordinate systems with the electromagnetic torque equation of the six-phase permanent magnet synchronous motor, the current in the two-phase synchronous rotating coordinate system is obtained: Among them, i α1 、i β1 and i α2 、i β2 Represent the current in two independent α-β coordinate systems, i α 、i β and i x 、i y Represents the current in the two-phase synchronous rotating coordinate system; The electromagnetic torque equation of the six-phase permanent magnet synchronous motor is: T e =3p n and q [i d (L d -L q )+ψ f ]; Among them, T e is the electromagnetic torque, p n is the pole pair number, L d , L q is the inductance in the two-phase synchronous rotating coordinate system, ψ f is the rotor flux, i d 、i q is the stator current in the two-phase synchronous rotating coordinate system.

4. The method for self-adaptive fault-tolerant control of a six-phase permanent magnet synchronous motor under an open circuit fault according to claim 3, characterized in that: The step of obtaining the relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the current of the two-phase stationary coordinate system according to the two-phase synchronous rotating coordinate system comprises: The two-phase synchronous rotating coordinate system is combined with the motion equation of the six-phase permanent magnet synchronous motor to obtain the current relationship between the q-axis current of the six-phase permanent magnet synchronous motor and the two-phase stationary coordinate system, which is: The motion equation of the six-phase permanent magnet synchronous motor is: Among them, T e is the electromagnetic torque, T L is the load torque, B is the damping coefficient, J is the moment of inertia, and ω is the mechanical angular velocity.

5. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 1 is characterized in that: The step of optimizing the reference current by a phase-locked loop of a second-order generalized integrator comprises: S1, obtain input signal; S2, decomposes the input signal into a pair of orthogonal signals; S3, obtaining and comparing the quadrature signal with the control signal of the reference current to generate a phase error signal; S4, filtering and smoothing the phase error signal to obtain a new reference current control signal.

6. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 1 is characterized in that: The improved repetitive controller comprises a periodic signal generator, a controller gain, a low-pass filter and a phase advance compensation link.

7. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 1, characterized in that: The step of suppressing the harmonic components and periodic disturbance of the new reference current in the two-phase stationary coordinate system under the open circuit fault by improving the repetitive controller comprises: S1, inputs the error signal into the internal model to generate a signal with the same frequency and phase characteristics as the controlled periodic signal; S2, filtering the signal generated by the internal model through a low-pass filter to remove high-frequency interference signals; S3, performing phase compensation on the filtered signal through a phase advance compensation link to compensate for control and transmission delays; S4, adjusting the signal amplitude after the above processing by the controller gain to adjust the system error convergence rate; S5, outputting the final processed signal as a control signal to adjust the actual output of the system; S6, compare the actual output of the system with the expected output again to form a closed-loop control; S7, converts the repetitive controller in the continuous domain into the discrete domain for implementation in a digital control system.

8. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 1, characterized in that: The mathematical formula of the variable gain PI controller is: Where: e(t) is the input of the controller, y(t) is the output of the variable gain PI controller, K p is the proportional gain, K i is the integral gain.

9. The diagnosis-free adaptive fault-tolerant control method for a six-phase permanent magnet synchronous motor under an open-circuit fault according to claim 8, characterized in that: The switching formula of the proportional gain is: Among them, K p Represents the proportional gain, which changes with time t. <T s When K pi Increase to K pf , where n is the exponential factor, T s is the switching time, when t ≥ T s When the proportional gain is fixed at K pf ; The switching formula of the integral gain is: Among them, K i When t<T s It will gradually increase when t>T s When it is fixed as a constant, K if is the initial integral gain, K i is the integral gain; The unit step response formula of the variable gain PI controller is: 。 10. A diagnosis-free adaptive fault-tolerant control system for a six-phase permanent magnet synchronous motor under an open-circuit fault, characterized in that: include: PI controller module, improved repetitive controller module and second-order generalized integrator-based phase-locked loop; The phase-locked loop based on the second-order generalized integrator is used to process and optimize the current in the two-phase stationary coordinate system; The improved repetitive controller module is used to receive the output from the second-order generalized integrator-based phase-locked loop and suppress the harmonic components and periodic disturbances of the new reference current in the two-phase stationary coordinate system under the open circuit fault; The PI controller module is used to output an updated compensated current.

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