A method and system for open-circuit fault diagnosis of a five-phase permanent magnet fault-tolerant motor system

Abstract

The application relates to an open-circuit fault diagnosis method and system of a five-phase permanent magnet fault-tolerant motor system, and belongs to the technical field of fault-tolerant motors. The method solves the problems that the existing fault diagnosis process is complex, involves many parameters, has a high calculation amount, and is difficult to improve the speed and efficiency of fault diagnosis. The method comprises the following steps: performing Park vector transformation on collected phase currents to obtain an average value of a real part and an average value of an imaginary part of a current vector in a current period; performing normalization processing on the collected operation data of the motor in the current period to obtain a normalized average value of the real part, a normalized average value of the imaginary part, a normalized average value of a modulus value and a normalized vector angle; judging whether the normalized average value of the modulus value is greater than a preset fault threshold value; if yes, an open-circuit fault occurs in the current period; and the position of a power switch tube of the five-phase permanent magnet fault-tolerant motor in the current period is determined based on the normalized average value of the real part, the normalized average value of the imaginary part and the normalized vector angle.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fault-tolerant motor technology, in particular to a method and system for open-circuit fault diagnosis of a five-phase fault-tolerant permanent magnet motor system. BACKGROUND

[0002] With the development of power electronics technology, motor control technology and rare earth permanent magnet materials, permanent magnet motors have ushered in new development opportunities and challenges. In addition to requiring high power density and high efficiency, they also need to have high output performance and high reliability, which has become the key to the development of permanent magnet motors. Although high-reliability permanent magnet synchronous motors have fault-tolerant operation capability, the motor is in an abnormal operating state after a fault occurs. If the fault cannot be detected and located in time, it may cause further damage to the motor. Therefore, a fast and accurate fault diagnosis strategy is a prerequisite for fault-tolerant operation of the servo motor system. The main fault sources of the high-reliability permanent magnet synchronous motor system are motor body faults, drive system inverter faults and sensor faults. Among them, the permanent magnet synchronous motor system faults all come from the drive system inverter faults, and the most common one is the open-circuit fault of the power switch tube.

[0003] At present, the open-circuit fault diagnosis method of the power switch tube is usually based on the current signal. The fault diagnosis method is based on the analysis and processing of the current feedback data collected by the existing current sensor of the motor system. It does not need to increase additional sensor equipment and is independent of the motor system parameters. Therefore, the current detection method has a wide application in the field of motor fault detection. However, most of the current signal-based fault diagnosis methods are for traditional three-phase motor systems and cannot be directly used for multi-phase permanent magnet fault-tolerant motor systems. A small part of the research on open-circuit fault diagnosis of multi-phase permanent magnet fault-tolerant motor systems is complex, involves many parameters, and has high computational complexity, making it difficult to improve the speed and efficiency of fault diagnosis. SUMMARY

[0004] In view of the above analysis, the embodiments of the present application aim to provide an open-circuit fault diagnosis method and system for a five-phase permanent magnet fault-tolerant motor system to solve the problem of complex fault diagnosis process, multiple parameters involved, high computational complexity, and difficulty in improving the speed and efficiency of fault diagnosis.

[0005] In one aspect, the embodiments of the present application provide an open-circuit fault diagnosis method for a five-phase permanent magnet fault-tolerant motor system, comprising the following steps:

[0006] Park vector transformation is performed on the collected current of each phase of the five-phase permanent magnet fault-tolerant motor in the current cycle to obtain the average value of the real part and the average value of the imaginary part of the current vector in the current cycle.

[0007] Based on the rotor electric angle speed, the electric angle, the rotation speed, the fault state of each phase and the proportional integral controller output value of the previous current cycle of the five-phase permanent fault-tolerant motor collected in the current cycle, the real part average value and the imaginary part average value of the current vector are normalized to obtain the real part normalized average value, the imaginary part normalized average value, and further obtain the normalized average value of the modulus and the normalized vector angle;

[0008] It is judged whether the normalized average value of the modulus is greater than the preset fault threshold value, if yes, it is judged that the open circuit fault occurs in the current cycle, and the position of the power switch tube of the five-phase permanent fault-tolerant motor in the current cycle is determined based on the real part normalized average value, the imaginary part normalized average value and the normalized vector angle.

[0009] Further, the normalized vector angle θ Nav is expressed as:

[0010]

[0011] In the formula, I αNav and I βNav respectively represent the real part normalized average value and the imaginary part normalized average value.

[0012] Further, the real part normalized average value I αNav and the imaginary part normalized average value I βNav are respectively expressed as:

[0013]

[0014]

[0015] In the formula, I Norm represents the normalized reference value of the current vector, I αav , I βav respectively represent the real part average value and the imaginary part average value of the current vector in the current cycle.

[0016] Further, the real part average value and the imaginary part average value I αav of the current vector in the current cycle are respectively expressed as: βav

[0017]

[0018]

[0019] In the formula, T represents the current cycle, I A , I B , I C , I D , I E ​respectively represent the currents of the A, B, C, D, and E phases of the five-phase permanent-magnet fault-tolerant motor in the current cycle.

[0020] Further, the current vector normalization reference value I Norm is represented as:

[0021]

[0022] wherein,

[0023]

[0024]

[0025] S N ∪S F ={A, B, C, D, E};

[0026] θ eA = 0,

[0027] In the formula, S N represents a set of non-faulty phase windings of the five-phase permanent-magnet fault-tolerant motor in the current cycle; S F represents a set of faulty phase windings of the five-phase permanent-magnet fault-tolerant motor in the current cycle; ω e represents the rotor electrical angular velocity of the five-phase permanent-magnet fault-tolerant motor in the current cycle; θ ei represents the initial electrical angle of the i-th winding; θ ef represents the initial electrical angle of the f-th winding; u' q represents the output value of the integral term of the proportional-integral controller in the previous current cycle; x represents the electrical angle of the five-phase permanent-magnet fault-tolerant motor in the current cycle; k m represents the peak back electromotive force coefficient of the five-phase permanent-magnet fault-tolerant motor, k p , and k h respectively represent the proportional coefficient and the integral coefficient of the speed controller; represents the speed command of the five-phase permanent-magnet fault-tolerant motor in the current cycle; ω m represents the mechanical speed of the five-phase permanent-magnet fault-tolerant motor in the current cycle.

[0028] Further, the fault threshold I TH is determined according to the following formula:

[0029]

[0030] In the formula, μ represents a fault threshold coefficient.

[0031] Further, the modulus normalization average value I modNav is represented as:

[0032]

[0033] Further, the position of the power switch tube of the five-phase permanent magnet fault-tolerant motor appearing open circuit fault in the current cycle is determined by the following way:

[0034] If I αNav <0, I βNav = 0, and θ Nav = 0, the fault position is the power switch tube S A1 or S A4 in the H-bridge positive bridge arm of the full-bridge circuit of the A phase;

[0035] If I αNav > 0, I βNav = 0, and θ Nav = 0, the fault position is the power switch tube S A2 or S A3 in the H-bridge negative bridge arm of the full-bridge circuit of the A phase;

[0036] If I αNav < 0, I βNav < 0, the fault position is the power switch tube S B1 or S B4 in the H-bridge positive bridge arm of the full-bridge circuit of the B phase;

[0037] If I αNav > 0, I βNav > 0, the fault position is the power switch tube S B2 or S B3 in the H-bridge negative bridge arm of the full-bridge circuit of the B phase;

[0038] If I αNav > 0, I βNav < 0, the fault position is the power switch tube S C1 or S C4 in the H-bridge positive bridge arm of the full-bridge circuit of the C phase;

[0039] If I αNav < 0, I βNav > 0, the fault position is the power switch tube S C2 or S C3 in the H-bridge negative bridge arm of the full-bridge circuit of the C phase;

[0040] If I αNav > 0, I βNav > 0, The fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase D. D1 or S D4 ;

[0041] If I is satisfied at the same time αNav <0, I βNav <0、 The fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase D. D2 or S D3 ;

[0042] If I is satisfied at the same time αNav <0, I βNav >0、 The fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase E. E1 or S E4 ;

[0043] If I is satisfied at the same time αNav >0, I βNav <0、 The fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase E. E2 or S E3 ;

[0044] Otherwise, the location of the fault cannot be determined.

[0045] Furthermore, the fault threshold coefficient μ is set to 0.75.

[0046] On the other hand, embodiments of the present invention provide an open-circuit fault diagnosis system for a five-phase permanent magnet fault-tolerant motor system, comprising:

[0047] The data acquisition module is used to collect the phase current, rotor electric angular velocity, electric angle, speed, phase fault status, and proportional-integral controller output value of the five-phase permanent magnet fault-tolerant motor in the current current cycle.

[0048] The data processing module is used to perform Park vector transformation based on the current of each phase to obtain the average value of the real part and the average value of the imaginary part of the current vector within one current cycle; then, based on the collected data, the average value of the real part and the average value of the imaginary part of the current vector are normalized to obtain the normalized average value of the real part and the normalized average value of the imaginary part, and then the normalized average value of the magnitude and the normalized vector angle are obtained.

[0049] The fault diagnosis and location module is used to determine whether the normalized average value of the modulus is greater than the preset fault threshold. If it is greater, it is determined that an open circuit fault has occurred in the current current cycle. Based on the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle, the position of the power switch tube in the five-phase permanent magnet fault-tolerant motor with an open circuit fault in the current current cycle is determined.

[0050] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0051] This invention provides a method and system for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system. By collecting data, it obtains the normalized average value of the real part, the normalized average value of the imaginary part, the normalized vector angle, and the normalized average value of the magnitude. Using the normalized average value of the magnitude as the fault diagnosis variable improves the resistance to sudden changes in speed and load, resulting in better robustness. Furthermore, the location of the power switch transistor experiencing an open-circuit fault in the five-phase permanent magnet fault-tolerant motor during the current current cycle is determined using the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle. Moreover, the location of open-circuit faults in different power transistors can be achieved using only three variables, effectively simplifying the calculation and improving the diagnostic speed and efficiency.

[0052] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0053] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0054] Figure 1 This is a flowchart illustrating the open-circuit fault diagnosis method for a five-phase permanent magnet fault-tolerant motor system provided in Embodiment 1 of the present invention.

[0055] Figure 2 This is a schematic diagram of the overall structure of the five-phase permanent magnet fault-tolerant motor system provided in Embodiment 2 of the present invention;

[0056] Figure 3 This is a schematic diagram of the functional allocation modules of the DSP system and FPGA system provided in Embodiment 2 of the present invention;

[0057] Figure 4 This is a schematic diagram of the structure of the five-phase H-bridge architecture fault-tolerant power drive circuit provided in Embodiment 2 of the present invention;

[0058] Figure 5 This is a schematic diagram of the fault diagnosis module in the DSP system provided in Embodiment 2 of the present invention. Detailed Implementation

[0059] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0060] Example 1

[0061] A specific embodiment of the present invention discloses a method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system, such as... Figure 1 As shown, it includes the following steps:

[0062] S1. Perform Park vector transformation on the current of each phase of the five-phase permanent magnet fault-tolerant motor collected in the current current cycle to obtain the average value of the real part and the average value of the imaginary part of the current vector in the current current cycle.

[0063] During implementation, in step S1, the average value of the real part and the average value of the imaginary part of the current vector in the current current cycle are I. αav I βav , respectively represented as:

[0064]

[0065]

[0066] In the formula, T represents the current period, and I... A I B I C I D I E These represent the currents of phases A, B, C, D, and E of the five-phase permanent magnet fault-tolerant motor during the current current cycle.

[0067] It should be noted that in step S1, the average real part and the average imaginary part of the current vector for the current current cycle are obtained based on the following process:

[0068] The Park vector transformation is performed on the current of each phase of the five-phase permanent magnet fault-tolerant motor during the current current cycle, as shown in the following formula:

[0069]

[0070] In the formula, I α I β These represent the real and imaginary parts of the current vector for the current cycle, respectively.

[0071] Current vector It can be represented as:

[0072]

[0073] in,

[0074] In the formula, I mod Represents the current vector The modulus.

[0075] Therefore, the average real part and average imaginary part of the current vector I within the current current period T can be obtained by the following formula. αav I βav :

[0076]

[0077]

[0078] S2. Based on the rotor electric angular velocity, electric angle, speed, fault status of each phase, and proportional-integral controller output value of the five-phase permanent magnet fault-tolerant motor in the current current cycle, the average value of the real part and the average value of the imaginary part of the current vector are normalized to obtain the normalized average value of the real part and the normalized average value of the imaginary part, and then the normalized average value of the modulus and the normalized vector angle are obtained.

[0079] Specifically, in step S2, the normalized reference value of the current vector is obtained based on the rotor electric angular velocity, speed, fault status of each phase of the five-phase permanent magnet fault-tolerant motor in the current current cycle and the output value of the proportional-integral controller in the previous current cycle. The average value of the real part and the average value of the imaginary part of the current vector are normalized based on the normalized reference value of the current vector.

[0080] During implementation, the current vector normalization reference value I Norm , represented as:

[0081]

[0082] in,

[0083]

[0084]

[0085] S N ∪S F ={A,B,C,D,E};

[0086] θ eA =0,

[0087] In the formula, S N S represents the set of non-faulty phase windings of a five-phase permanent magnet fault-tolerant motor during the current current cycle; F This represents the set of faulty phase windings in a five-phase permanent magnet fault-tolerant motor during the current current cycle; ω e θ represents the rotor electric angular velocity of the five-phase permanent magnet fault-tolerant motor during the current cycle. eiθ represents the initial electrical angle of the i-th phase winding; ef u′ represents the initial electrical angle of the f-th phase winding; q The value of the integral term of the proportional-integral controller in the previous current cycle is represented by x; x represents the electrical angle of the five-phase permanent magnet fault-tolerant motor in the current current cycle; k m k represents the peak back EMF coefficient of a five-phase permanent magnet fault-tolerant motor. p k h These represent the proportional and integral coefficients of the speed controller, respectively. This indicates the speed command for the five-phase permanent magnet fault-tolerant motor during the current current cycle; ω m This indicates the mechanical speed of the five-phase permanent magnet fault-tolerant motor during the current current cycle.

[0088] Further, in step S2, the normalized average value of the real part I αNav Normalized average of the imaginary part I βNav , respectively represented as:

[0089]

[0090]

[0091] In the formula, I Norm I represents the normalized reference value of the current vector. αav I βav These represent the average real part and the average imaginary part of the current vector for the current current cycle, respectively.

[0092] Further, in step S2, the normalized vector angle θ Nav , represented as:

[0093]

[0094] In the formula, I αNav I βNav and represent the normalized average of the real part and the normalized average of the imaginary part, respectively.

[0095] Furthermore, the normalized average value of the modulus I modNav , represented as:

[0096]

[0097] S3. Determine whether the normalized average value of the modulus is greater than the preset fault threshold. If it is greater, determine that an open circuit fault has occurred in the current current cycle. Based on the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle, determine the position of the power switch tube that has failed in the five-phase permanent magnet fault-tolerant motor in the current current cycle.

[0098] During implementation, the fault threshold I THDetermined according to the following formula:

[0099]

[0100] In the formula, μ represents the fault threshold coefficient. The setting of the fault threshold coefficient is based on the system's requirements for speed and sensitivity in fault diagnosis.

[0101] Preferably, the fault threshold coefficient μ is set to 0.75, at which point the corresponding fault threshold I... TH =0.095.

[0102] It should be noted that the fault threshold setting method is obtained through the following analysis process:

[0103] After a single-phase open-circuit fault occurs in a five-phase permanent magnet fault-tolerant motor, the normalized average value of the magnitude of the current vector can be expressed as:

[0104]

[0105] in,

[0106]

[0107] Let z = ω e t, We can obtain:

[0108]

[0109] In the formula, I f This represents the current in phase f of a five-phase permanent magnet fault-tolerant motor during the current cycle, S. n1 S n4 In the full-bridge circuit constituting the nth phase, the positive arm of the H-bridge, S n2 S n3 The negative arm of the H-bridge in the full-bridge circuit that constitutes the nth phase; n represents the five phases A, B, C, E, and D of the five-phase permanent magnet fault-tolerant motor.

[0110] When a multi-phase open-circuit fault occurs in a five-phase permanent magnet fault-tolerant motor, the normalized average value of the magnitude is greater than that of a single-phase open-circuit fault. Therefore, a fault threshold for diagnosing open-circuit faults is obtained, expressed as:

[0111]

[0112] During implementation, in step S3, the location of the power switch transistor that causes an open-circuit fault in the five-phase permanent magnet fault-tolerant motor during the current current cycle is determined in the following way:

[0113] If I is satisfied at the same time αNav <0, I βNav =0, θ Nav=0, then the fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase A. A1 or S A4 ;

[0114] If I is satisfied at the same time αNav >0, I βNav =0, θ Nav =0, then the fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase A. A2 or S A3 ;

[0115] If I is satisfied at the same time αNav <0, I βNav <0、 The fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase B. B1 or S B4 ;

[0116] If I is satisfied at the same time αNav >0, I βNav >0、 The fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase B. B2 or S B3 ;

[0117] If I is satisfied at the same time αNav >0, I βNav <0、 The fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase C. C1 or S C4 ;

[0118] If I is satisfied at the same time αNav <0, I βNav >0、 The fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase C. C2 or S C3 ;

[0119] If I is satisfied at the same time αNav >0, I βNav >0、 The fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase D. D1 or S D4 ;

[0120] If I is satisfied at the same time αNav <0, I βNav <0、 The fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase D. D2 or SD3 ;

[0121] If I is satisfied at the same time αNav <0, I βNav >0、 The fault location is the power switch S in the positive arm of the H-bridge in the full-bridge circuit of phase E. E1 or S E4 ;

[0122] If I is satisfied at the same time αNav >0, I βNav <0、 The fault location is the power switch S in the negative arm of the H-bridge in the full-bridge circuit of phase E. E2 or S E3 ;

[0123] Otherwise, the location of the fault cannot be determined.

[0124] It should be noted that the above-described fault location process can diagnose open-circuit faults in a five-phase permanent magnet fault-tolerant motor system and locate the fault location of a single-phase single-power transistor. If the fault cannot be located, it can be identified as another type of fault. This process can quickly distinguish between single-phase single-power transistor faults and other types of faults, and improve the speed and efficiency of single-power transistor fault location.

[0125] Compared with existing technologies, this embodiment provides an open-circuit fault diagnosis method for a five-phase permanent magnet fault-tolerant motor system. By collecting data, it obtains the normalized average value of the real part, the normalized average value of the imaginary part, the normalized vector angle, and the normalized average value of the magnitude. Using the normalized average value of the magnitude as the fault diagnosis variable improves the resistance to interference from sudden changes in speed and load, resulting in better robustness. Furthermore, the location of the faulty power switch in the five-phase permanent magnet fault-tolerant motor during the current current cycle is determined using the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle. The location of open-circuit faults in different power switches can be achieved using only three variables, effectively simplifying the calculation and improving the diagnostic speed and efficiency. In addition, the diagnostic method of this embodiment only needs to utilize the existing control structure variables of the system, without the need for additional sensors or other detection equipment, greatly reducing the computational load and hardware implementation difficulty of the fault diagnosis method.

[0126] Example 2

[0127] A specific embodiment 2 of the present invention provides an open-circuit fault diagnosis system for a five-phase permanent magnet fault-tolerant motor system, comprising:

[0128] The data acquisition module is used to collect the phase current, rotor electric angular velocity, electric angle, speed, phase fault status, and proportional-integral controller output value of the five-phase permanent magnet fault-tolerant motor in the current current cycle.

[0129] The data processing module is used to perform Park vector transformation based on the current of each phase to obtain the average value of the real part and the average value of the imaginary part of the current vector within one current cycle; then, based on the collected data, the average value of the real part and the average value of the imaginary part of the current vector are normalized to obtain the normalized average value of the real part and the normalized average value of the imaginary part, and then the normalized average value of the magnitude and the normalized vector angle are obtained.

[0130] The fault diagnosis and location module is used to determine whether the normalized average value of the modulus is greater than the preset fault threshold. If it is greater, it determines that an open circuit fault has occurred in the current current cycle, and determines the location of the power switch tube in the five-phase permanent magnet fault-tolerant motor that has an open circuit fault in the current current cycle based on the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle.

[0131] Specifically, such as Figure 2 As shown, the fault-tolerant motor system includes a five-phase permanent magnet fault-tolerant motor, a fault-tolerant controller, a fault-tolerant power driver, and a signal detection circuit.

[0132] More specifically, the five-phase permanent magnet fault-tolerant motor includes stator and rotor assemblies, rotary transformers and components such as shafts, bearings, housings, front and rear end covers, etc. The stator has a ten-slot structure and adopts a short-circuit resistant slot design. The windings of each phase are interleaved with teeth. The permanent magnets of the rotor assembly have a four-pole surface-mount structure.

[0133] More specifically, such as Figure 3 As shown, the fault-tolerant controller mainly includes a DSP system and an FPGA system. The fault-tolerant controller performs speed loop calculations based on the acquired rotational speed and speed commands from the host computer to obtain the given command for the electromagnetic torque. Simultaneously, based on the acquired current feedback value, the fault diagnosis module detects open circuits in the power switches in real time to obtain the system's fault status. Then, based on the electromagnetic torque command, rotor position feedback information, and the system's fault status, the fault-tolerant control strategy module calculates the given command for the remaining normal phase current of the motor. Next, based on the given current command and current feedback value, the current loop is calculated to obtain the given voltage for each phase. Finally, based on the given voltage for each phase and the system fault status, the PWM generation module outputs a PWM control signal. The PWM control signal is amplified by an isolated drive circuit and then sent to the five-phase fault-tolerant power driver to control the switching on and off of 20 power switches.

[0134] Furthermore, the DSP system includes a speed controller, a fault-tolerant controller, and a fault diagnosis module. The speed controller performs speed loop calculations based on speed commands from the host computer and speed feedback values ​​input from the FPGA. The fault diagnosis module obtains the real-time fault status of the system by detecting power switches based on the five-phase current feedback values ​​input from the FPGA. The fault-tolerant controller calculates the fault-tolerant control strategy based on the electromagnetic torque setpoint, rotor position feedback input from the FPGA, and the real-time fault status, obtaining the current setpoint for the non-faulty windings of the motor, and then sends this setpoint to the FPGA.

[0135] Furthermore, the FPGA system includes a current controller, a current A / D sampling control module, a resolver control module, a PWM generation module, and a data transmission module. The current controller performs current loop calculations based on the current command input from the DSP and the current feedback value obtained from the A / D sampling control module to obtain the voltage command. The current A / D sampling control module is responsible for controlling current sampling. The resolver control module is responsible for controlling the motor position and speed sampling. The PWM generation module outputs PWM control signals for 20 power switches based on the given voltage of each phase and the motor fault status. The data transmission module is responsible for enabling parallel communication between the FPGA and the DSP.

[0136] Preferably, the DSP system uses a high-performance 32-bit floating-point digital processor TMS320F28335 with a main frequency of up to 150MHz. It has a single-precision floating-point arithmetic unit, 256K×16 FLASH, 34K×16 SARAM, 8K×16 boot ROM, supports up to 18 channels of PWM output, and CAN, UART, SPI, and I2C communication interfaces. The FPGA system consists of an FPGA chip and its peripheral circuits. The FPGA chip selected is the Altera Cyclone II series EP2C35F484C8N. The EP2C35F484C8N features low power consumption and low cost, a working clock frequency of up to 400MHz, 33216 logic units, 35 multipliers, and provides up to 328 configurable I / O ports.

[0137] More specifically, the signal detection circuit includes a current sensor, a rotary transformer, a shaft angle converter, a signal conditioning circuit, and an A / D conversion circuit; it is used to acquire the phase current signal of the motor, the motor speed, and the rotor position information. The accuracy and response speed of the signal detection circuit have a direct impact on the control performance of the system.

[0138] More specifically, fault-tolerant power drivers, such as Figure 4As shown, the system, consisting of an isolation drive circuit and an H-bridge inverter circuit, is a key component of the motor drive control system. The driver, based on control commands from the fault-tolerant controller, controls the switching on and off of 20 power transistors, thereby providing the required drive current to each phase winding of the five-phase permanent magnet fault-tolerant motor. Furthermore, when a fault is detected, the fault-tolerant power driver needs to quickly isolate the fault. The isolation driver consists of a gate isolation driver chip and its peripheral circuitry, achieving electrical isolation and improving system stability; the inverter circuit consists of five independent full-bridge circuits, each H-bridge circuit consisting of four power transistors (S...). n1 S n2 S n3 S n4 Composition, in which S n1 With S n4 The positive arm of the H-bridge, which makes up the n phases, S n2 With S n3 The negative bridge arm of the H-bridge, which consists of n phases, enables individual drive and power supply for each phase winding of the permanent magnet fault-tolerant motor, thus forming an electrical fault-tolerant structure between the phase windings.

[0139] When implementing, such as Figure 5 As shown in the diagram, the fault diagnosis module in the DSP system of this implementation first samples the five-phase current I... A I B I C I D I E Perform Park vector transformation to obtain the current vector. Then calculate the current vector. The average value over the current cycle, output current vector The real part average value I αav The average value of the imaginary part I βav Then, the average values ​​are normalized to obtain the current vector. Real part normalized mean I αNav Normalized average of the imaginary part I βNav This leads to the normalized average value I of the modulus. modNav Normalized vector angle θ Nav By comparing the normalized average value I of the modulus modNav With fault threshold I TH Output a fault occurrence signal; finally, based on the normalized average value I of the real part... αNav Normalized average of the imaginary part I βNav Normalized vector angle θ Nav Perform fault location and finally output the fault status result.

[0140] The specific implementation process of this invention can be found in the above method embodiments, and will not be repeated here.

[0141] Since this embodiment is based on the same principle as the above-described method embodiments, this system also has the corresponding technical effects of the above-described method embodiments.

[0142] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0143] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system, characterized in that, Includes the following steps: The Park vector transformation is performed on the phase currents of the five-phase permanent magnet fault-tolerant motor collected in the current current cycle to obtain the average real part and the average imaginary part of the current vector in the current current cycle. Based on the collected rotor electric angular velocity, electric angle, speed, fault status of each phase, and proportional-integral controller output value of the five-phase permanent magnet fault-tolerant motor in the current current cycle, the average real part and average imaginary part of the current vector are normalized to obtain the normalized average real part and normalized average imaginary part, and then the normalized average magnitude and normalized vector angle are obtained. Specifically, a normalized reference value for the current vector is derived based on the collected rotor electric angular velocity, speed, fault status of each phase, and proportional-integral controller output value of the five-phase permanent magnet fault-tolerant motor in the current current cycle. The average real part and average imaginary part of the current vector are then normalized based on this reference value. , is represented as: ； in, ； ； ； ， ， ， ， ； In the formula, This represents the set of non-faulty phase windings of a five-phase permanent magnet fault-tolerant motor during the current current cycle. This represents the set of faulty phase windings in a five-phase permanent magnet fault-tolerant motor during the current current cycle. This indicates the current current cycle rotor electric angular velocity of the five-phase permanent magnet fault-tolerant motor; Indicates the first i Initial electrical angle of phase winding; Indicates the first f Initial electrical angle of phase winding; This represents the output value of the integral term of the proportional-integral controller in the previous current cycle; x This represents the electrical angle of a five-phase permanent magnet fault-tolerant motor during the current current cycle. This represents the peak back EMF coefficient of a five-phase permanent magnet fault-tolerant motor. , These represent the proportional and integral coefficients of the speed controller, respectively. This indicates the speed command of the five-phase permanent magnet fault-tolerant motor during the current current cycle. This indicates the mechanical speed of the five-phase permanent magnet fault-tolerant motor during the current current cycle; A, B, C, D, and E represent the currents of phases A, B, C, D, and E of the five-phase permanent magnet fault-tolerant motor, respectively. Determine whether the normalized average value of the modulus is greater than the preset fault threshold. If it is, determine that an open circuit fault has occurred in the current current cycle, and determine the position of the power switch tube in the five-phase permanent magnet fault-tolerant motor that has an open circuit fault in the current current cycle based on the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle.

2. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 1, characterized in that, The normalized vector angle , is represented as: In the formula, , and represent the normalized average of the real part and the normalized average of the imaginary part, respectively.

3. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 2, characterized in that, The normalized average value of the real part Normalized average of the imaginary part , respectively represented as: In the formula, This represents the reference value for the normalized current vector. , These represent the average real part and the average imaginary part of the current vector for the current current cycle, respectively.

4. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 3, characterized in that, The real average and imaginary average of the current vector in the current current cycle , , respectively represented as: In the formula, T Indicates the current period. , , , , These represent the current cycle of the five-phase permanent magnet fault-tolerant motor. A , B , C , D , E The current in the phase.

5. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 1, characterized in that, The fault threshold Determined according to the following formula: In the formula, This represents the fault threshold coefficient.

6. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 3, characterized in that, The normalized average value of the modulus , is represented as: 。 7. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 2, characterized in that, The location of the power switch transistor that causes an open-circuit fault in the five-phase permanent magnet fault-tolerant motor during the current current cycle can be determined using the following method: If both conditions are met , , The fault location is the power switch transistor in the positive arm of the H-bridge in the full-bridge circuit of phase A. or ; If both conditions are met , , The fault location is the power switch transistor in the negative arm of the H-bridge in the full-bridge circuit of phase A. or ; If both conditions are met , , The fault location is the power switch transistor in the positive arm of the H-bridge in the full-bridge circuit of phase B. or ; If both conditions are met , , The fault location is the power switch transistor in the negative arm of the H-bridge in the full-bridge circuit of phase B. or ; If both conditions are met , , The fault location is the power switch transistor in the positive arm of the H-bridge in the full-bridge circuit of phase C. or ; If both conditions are met , , The fault location is the power switch transistor in the negative arm of the H-bridge in the full-bridge circuit of phase C. or ; If both conditions are met , , The fault location is the power switch transistor in the positive arm of the H-bridge in the full-bridge circuit of phase D. or ; If both conditions are met , , The fault location is the power switch transistor in the negative arm of the H-bridge in the full-bridge circuit of phase D. or ; If both conditions are met , , The fault location is the power switch transistor in the positive arm of the H-bridge in the full-bridge circuit of phase E. or ; If both conditions are met , , The fault location is the power switch transistor in the negative arm of the H-bridge in the full-bridge circuit of phase E. or ; Otherwise, the location of the fault cannot be determined.

8. The method for diagnosing open-circuit faults in a five-phase permanent magnet fault-tolerant motor system according to claim 5, characterized in that, The fault threshold coefficient The value is 0.

75.

9. An open-circuit fault diagnosis system for a five-phase permanent magnet fault-tolerant motor system, characterized in that, include: The data acquisition module is used to collect the phase current, rotor electric angular velocity, electric angle, speed, phase fault status, and proportional-integral controller output value of the five-phase permanent magnet fault-tolerant motor in the current current cycle. The data processing module performs Park vector transformation based on the current of each phase to obtain the average real and imaginary parts of the current vector within one current cycle. Then, based on the acquired data, it normalizes the average real and imaginary parts of the current vector to obtain the normalized average real and imaginary parts, and further obtains the normalized average magnitude and normalized vector angle. Specifically, based on the acquired rotor electric angular velocity, speed, fault status of each phase of the five-phase permanent magnet fault-tolerant motor in the current current cycle, and the proportional-integral controller output value from the previous current cycle, a normalized reference value for the current vector is derived. The average real and imaginary parts of the current vector are then normalized based on this reference value. , is represented as: in, ； ； ； ， ， ， ， ； In the formula, This represents the set of non-faulty phase windings of a five-phase permanent magnet fault-tolerant motor during the current current cycle. This represents the set of faulty phase windings in a five-phase permanent magnet fault-tolerant motor during the current current cycle. This indicates the current current cycle rotor electric angular velocity of the five-phase permanent magnet fault-tolerant motor; Indicates the first i Initial electrical angle of phase winding; Indicates the first f Initial electrical angle of phase winding; This represents the output value of the integral term of the proportional-integral controller in the previous current cycle; x This represents the electrical angle of a five-phase permanent magnet fault-tolerant motor during the current current cycle. This represents the peak back EMF coefficient of a five-phase permanent magnet fault-tolerant motor. , These represent the proportional and integral coefficients of the speed controller, respectively. This indicates the speed command of the five-phase permanent magnet fault-tolerant motor during the current current cycle. This indicates the mechanical speed of the five-phase permanent magnet fault-tolerant motor during the current current cycle. The fault diagnosis and location module is used to determine whether the normalized average value of the modulus is greater than the preset fault threshold. If it is greater, it is determined that an open circuit fault has occurred in the current current cycle. Based on the normalized average value of the real part, the normalized average value of the imaginary part, and the normalized vector angle, the position of the power switch tube in the five-phase permanent magnet fault-tolerant motor with an open circuit fault in the current current cycle is determined.

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