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CN-122001276-A - Fault diagnosis and fault-tolerant control method and system for double-winding permanent magnet synchronous motor

CN122001276ACN 122001276 ACN122001276 ACN 122001276ACN-122001276-A

Abstract

The invention provides a fault diagnosis and fault-tolerant control method and system of a double-winding permanent magnet synchronous motor, comprising the steps of designing a diagnosis method of open-circuit faults, ground faults and turn-to-turn short faults for a target motor of which the type is a double-winding permanent magnet synchronous motor, carrying out fault diagnosis on the target motor, outputting motor fault state marks, distinguishing corresponding motor fault states according to the obtained motor fault state marks, carrying out corner tracking control on the target motor if the target motor is fault-free, triggering corresponding fault-tolerant control schemes according to different fault states and applying corresponding constraint conditions if the target motor is in a fault state, and applying extra constraint on control current according to the fault type on the basis of the health state if the target motor is in a health state, so that the double-winding permanent magnet synchronous motor can stably operate under the health state and the fault state.

Inventors

  • HUANG WEI
  • LUO QILIN

Assignees

  • 福州大学

Dates

Publication Date
20260508
Application Date
20260212

Claims (10)

  1. 1. The fault diagnosis and fault tolerance control method for the double-winding permanent magnet synchronous motor is characterized by comprising the following steps of: Step S1, designing a diagnosis method of open-circuit faults, ground faults and turn-to-turn short circuit faults aiming at a target motor of which the type is a double-winding permanent magnet synchronous motor, carrying out fault diagnosis on the target motor, and outputting a motor fault state sign; Step S2, distinguishing a corresponding motor fault state according to the motor fault state mark obtained in the step S1, carrying out corner tracking control on the target motor without faults if the target motor is free of faults, and triggering a corresponding fault-tolerant control scheme according to different fault states if the target motor is in the fault state; And step S3, applying corresponding constraint conditions according to the control scheme determined in the step S2, and solving the control current, wherein if the control current is in a healthy state, the control current is only determined by a motor model of the target motor and the corner tracking controller, no additional constraint conditions exist, and if the control current is in a fault state, additional constraint is applied to the control current according to the fault type on the basis of the healthy state, so that the fault-tolerant control current is obtained, and the double-winding permanent magnet synchronous motor can stably operate in both the healthy state and the fault state.
  2. 2. The fault diagnosis and fault-tolerant control method of a double-winding permanent magnet synchronous motor according to claim 1, wherein step S1 comprises the following steps: Step S11, firstly, three-phase current signals of two sets of windings of a target motor are obtained through a current sensor, signal processing is carried out, sensor temperature drift is eliminated, and effectiveness of fault characteristics is ensured, wherein a sampling period is consistent with a control period of the target motor, signal timing synchronization is ensured, zero point calibration is carried out in a static state before the target motor is started aiming at the inherent zero point drift problem of the sensor, a drift compensation value is calculated by continuously collecting original current signals of a plurality of periods, and a zero value compensation function is as follows: ; in the formula, For the sampling current of the x-phase at time k, For the zero-value compensated phase current, M is the sampling period number of zero-value compensation, te is the motor torque; Step S12, in order to restrain high-frequency noise introduced by PWM modulation and electromagnetic interference and avoid residual error calculation distortion caused by signal phase lag, synchronous low-pass filtering processing is carried out on the calibrated sampling current and the reference current output by the current loop controller, and the filtering formulas are respectively as follows: sampling current filtering: ; In the middle of In order to sample the current after the filtering, Is a filter coefficient; Reference current filtering: ; In the middle of Is the filtered reference current; Step S13, calculating normalized phase current residual errors based on the preprocessed current signals, wherein the residual errors are converted into dimensionless relative values in the process of calculating the normalized phase current residual errors, and the calculation formula of the normalized residual errors is as follows: ; In the middle of The current residual for the x-phase at time k.
  3. 3. The fault diagnosis and fault-tolerant control method of a double-winding permanent magnet synchronous motor according to claim 2, wherein step S1 further comprises the following steps: step S14, designing an open circuit fault judging function of a target motor based on an amplitude threshold value, a duration period and a dynamic shielding triple judging logic, wherein the fault judging function adopts the amplitude threshold value, the duration period and the dynamic shielding triple judging logic; Wherein the first re-determination is to determine whether the single period residual is greater than a set threshold by an indication function; The second time is judged to be that whether the duration period of the residual overrun phenomenon is larger than the set period is judged through the summation function, and when the duration period of the residual overrun phenomenon is larger than the set period, the residual overrun is a continuous fault; The third heavy judgment is to design a dynamic shielding function, and the misjudgment problem caused by the fact that transient errors are larger and residual errors are rising due to the fact that the response speed of a current loop is limited is avoided by taking the change rate of the motor rotation speed as the identification basis; Wherein the open circuit fault determination function The design of (2) is as follows: ; Where N is the number of cycles for which the determination is continued, To indicate a function, its functional expression is: ; In the middle of Determining a threshold value for the set open circuit fault; Design of As a dynamic masking function, by rate of change of rotational speed To identify whether the system is in a large-range transient state working condition, the function expression is as follows: ; In the middle of Is the set rotational speed change rate threshold.
  4. 4. A fault diagnosis and fault-tolerant control method for a duplex winding permanent magnet synchronous motor according to claim 3, wherein step S1 further comprises the following steps: Step S15, designing a ground fault judging function of the target motor in a ground fault state according to the zero sequence current component, wherein the calculation formula of the zero sequence current residual error is as follows: ; Designed ground fault decision function The following are provided: ; wherein the ground indication function The expression of (2) is as follows: ; In the middle of And (5) determining a threshold value for the set ground fault.
  5. 5. The fault diagnosis and fault-tolerant control method of a double-winding permanent magnet synchronous motor according to claim 4, wherein step S1 comprises the following steps: Step S16, designing a time-frequency domain feature fusion and lightweight CNN diagnosis scheme to realize accurate recognition of turn-to-turn short circuit fault level, wherein the method comprises the following steps: extracting frequency domain features in the current signals through fast Fourier transformation, fusing the frequency domain features with time domain features obtained through statistics to form a multi-dimensional feature matrix, and inputting the multi-dimensional feature matrix into a CNN model; The designed CNN network structure comprises an input layer receiving a multidimensional feature matrix, a hidden layer comprising 3 series convolution blocks, wherein each convolution block follows a framework from a convolution layer to a batch normalization layer to a ReLU activation layer to a maximum pooling layer, key information is reserved while feature dimensions are compressed, convolution block output is flattened and then connected into a full-connection layer, a first full-connection layer is provided with a plurality of neurons, a subsequent series Dropout layer inhibits over fitting, a second full-connection layer is provided with 4 neurons and corresponds to 4 fault levels, an output layer converts neuron output into probability of each level through a Softmax function, and the maximum probability value is taken as a diagnosis result, namely 。
  6. 6. The fault diagnosis and fault-tolerant control method of a double-winding permanent magnet synchronous motor according to claim 5, wherein step S2 comprises the following steps: Step S21, judging the fault zone bit obtained in the step S1, and when the following formula is satisfied, the target motor is in a healthy state: ; if the target motor is in a healthy state, the target motor is directly subjected to corner tracking control, and no additional constraint condition is required to be applied to the current; step S22, judging the fault zone bit obtained in the step S1, and when the following formula is satisfied, the target motor is in a single-phase fault state: ; When the expression of the step S22 is satisfied, the target motor is in a phase open-circuit or turn-to-turn short circuit fault, and the corresponding fault-tolerant control scheme is that the main circuit of a phase bridge arm is cut off through a circuit breaker, and the phase power supply is cut off to perform fault isolation on the phase winding, so that the fault phase is prevented from being further enlarged and influenced; Step S23, judging the fault zone bit obtained in the step S1, and when the following formula is satisfied, the motor is in a winding fault state: ; When the expression of the step S23 is satisfied, the corresponding fault-tolerant control scheme is that the winding where the fault phase is located is integrally isolated, then the main circuit of the winding is cut off by a circuit breaker, and the power supply of the winding is cut off to carry out fault isolation on the winding.
  7. 7. The fault diagnosis and fault-tolerant control method of a double-winding permanent magnet synchronous motor according to claim 6, wherein step S3 comprises the following steps: step S31, designing a nonsingular rapid terminal sliding mode controller for controlling the rotation angle of a target motor in a healthy state, wherein the rotation angle tracking control comprises the following steps: defining the error as the difference between the reference rotation angle and the actual rotation angle, and the formula is as follows: ; The second order kinetic equation based on motor kinematics known error is: ; In the middle of The motor rotational inertia; The pole pair number of the motor is; is a permanent magnet flux linkage; is a damping coefficient; load torque for the motor; The designed sliding mode surface function is as follows: ; In the middle of Designing parameters for a sliding mode surface; Is a power factor and satisfies the constraint condition ; The designed sliding mode approach law is as follows: ; in the formula, Is the exponential approach rate; for switching gain; Is a smoothing factor; the sliding mode control law at this time can be deduced according to the above formula: ; ; Step S32, calculating the q-axis reference currents of each of the two sets of windings of the target motor in the healthy state, wherein the q-axis currents of the two sets of windings of the motor are equal and are both in the healthy state of the motor The method comprises the following steps: ; S33, inputting q-axis reference currents of the two sets of windings obtained in the step S32 into a current loop controller to realize corner tracking control; Step S34, when the target motor is in a single-phase fault, calculating fault-tolerant control phase current in the single-phase fault state according to the additional constraint in the single-phase fault in step S2, wherein the d-q axis current expression of the motor in the known health state is as follows: ; ; ; ; In the middle of D-axis currents of the first set and the second set of windings, respectively; Q-axis currents of the first and second sets of windings, respectively; is the electrical angle of the motor.
  8. 8. The fault diagnosis and fault-tolerant control method of a double-winding permanent magnet synchronous motor according to claim 7, wherein step S3 further comprises the following steps: Step S35, adopting two-phase four-switch modulation to replace a normal three-phase six-switch modulation strategy for the winding where the fault phase is located; step S36, if the winding is in fault, calculating fault-tolerant control current under winding isolation according to additional constraint under the single-phase fault in step S2, wherein as one set of windings is isolated and neutral points of two sets of windings are mutually independent, the original double-winding permanent magnet synchronous motor is degraded into a common three-phase permanent magnet synchronous motor, and the constraint is as follows: ; I.e. = The current of the healthy winding is multiplied and bears the total torque output; and S37, inputting the q-axis reference currents of the two sets of windings obtained in the step S36 into a current loop controller to realize corner tracking control.
  9. 9. A fault diagnosis and fault tolerance control system for a double winding permanent magnet synchronous motor, comprising an electronic device, wherein the electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements a fault diagnosis and fault tolerance control method for a double winding permanent magnet synchronous motor according to any one of claims 1 to 8 when executing the computer program.
  10. 10. A fault diagnosis and fault tolerance control system for a double winding permanent magnet synchronous motor, comprising a computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements a fault diagnosis and fault tolerance control method for a double winding permanent magnet synchronous motor according to any one of claims 1 to 8.

Description

Fault diagnosis and fault-tolerant control method and system for double-winding permanent magnet synchronous motor Technical Field The invention provides a fault diagnosis and fault tolerance control method and system for a double-winding permanent magnet synchronous motor, and relates to the technical field of intelligent network-connected automobile drive-by-wire chassis. Background Under the development trend of automobile intellectualization and automatic driving, a Steering-By-Wire (SBW) system has outstanding advantages in design flexibility, gear ratio adjustment and path planning suitability because of canceling physical connection of a Steering wheel and a Steering gear, and a double-winding permanent magnet synchronous motor becomes a core actuator meeting the highest safety requirement of an ASIL D level of an ISO 26262 standard By virtue of the hardware redundancy characteristic. However, in practical application, the fault diagnosis and fault-tolerant control of the motor still face a plurality of technical problems to be solved urgently, and the safety and the corner tracking precision of the steer-by-wire system are seriously affected. Aiming at three types of high-occurrence faults of single-phase open circuit, winding grounding and turn-to-turn short circuit of a double-winding permanent magnet synchronous motor, the existing method has obvious defects that 1) the single-phase open circuit is represented as current dip but is easy to be confused with normal current fluctuation under a load fluctuation scene, the existing detection method is easy to be missed, 2) the winding grounding can destroy three-phase current balance, the abnormal fluctuation characteristic of zero sequence current is easy to be covered by electromagnetic interference, the traditional threshold diagnosis is difficult to accurately capture, 3) the early stage of the turn-to-turn short circuit only involves few coils, the external electric characteristic change is weak, the external electric characteristic change is extremely easy to be covered by sensor noise and working condition fluctuation, the existing analytical model method cannot obtain balance between sensitivity and robustness, the high-precision algorithm based on learning is in need of large-scale data processing, such as deep learning, limited calculation force is not matched with a vehicle-mounted MCU, light-weight deployment is difficult to be realized, meanwhile, under the dynamic working conditions such as vehicle start-stop, large-angle steering and the like, the transient error of a current loop is similar to the fault residual error is easy to cause error, the system is easy to be unnecessarily reported, and the continuity is influenced. More importantly, the prior art does not form a complete fault-tolerant control system, so that the safety guarantee capability after the fault occurs is seriously insufficient. The method is characterized in that 1) when a motor has single-phase open circuit, winding grounding or turn-to-turn short circuit faults, a fault source cannot be cut off rapidly due to the lack of a specific fault isolation strategy and a topology reconstruction scheme, the fault spreading risk is high, 2) a current regulation and torque distribution mechanism adapting to a fault state is lacking, the torque output of the motor is easy to run away after the fault occurs, a steering system cannot maintain basic corner tracking capability, and 3) even if part of schemes try fault-tolerant treatment, torque pulsation compensation and steering stability cooperative control are not generally considered, so that driving smoothness and steering precision are obviously reduced under the fault state, and even the basic requirements of safe driving are difficult to meet. In summary, when the prior art is used for dealing with three types of high-frequency faults, the problems of insufficient diagnosis precision, difficulty in considering calculation force and diagnosis performance, easiness in misinformation under complex working conditions and the like exist, and a full-flow fault-tolerant solution for covering from fault isolation to torque control and from topology reconstruction to corner tracking is lacking. Therefore, a systematic fault diagnosis and fault tolerance control method is needed to be constructed, so as to fill the blank of the current technology, ensure that the steer-by-wire system meets the safety requirement of the ASIL D level function and ensure the stable and reliable operation performance of the steer-by-wire system. ‌ A Disclosure of Invention In view of the above, in order to make up for the blank and the deficiency of the prior art, the invention provides a fault diagnosis and fault tolerance control method and system for a double-winding permanent magnet synchronous motor. The invention aims to solve the problems of safety and corner tracking performance of a steer-by-wire system. The typical fault characteristics of the