Vector Fault-Tolerant Control For Reluctance Torque Improved Permanent Magnet Fault Tolerant Motors

Permanent magnet motor system has become the key and core of advanced manufacturing,electrified transportation,aerospace and other strategic emerging industries due to its advantages of high power density and high efficiency.However,motor systems all have a certain failure rate.After a motor system fails,it can cause equipment to stop or cause catastrophic consequences.Therefore,it is of great significance to study the permanent magnet fault-tolerant motor system.The Reluctance Torque Improved Permanent Magnet Fault Tolerant(RTI-PMFT)motor not only retains the advantages of the traditional permanent magnet fault tolerant motor with low short-circuit current and low phase coupling,but also improves the reluctance rotation in the motor.It effectively suppresses the overvoltage of the converter.This paper takes this new motor as the research object,and focuses on the analysis of the new fault-tolerant control strategy under winding open circuit and short-circuit faults.And it proposes Space Vector Pulse Width Modulation(SVPWM)open-circuit fault-tolerant drive technology to overcome the disadvantage that the converter switching frequency is difficult to fix during fault-tolerant operation;And it proposes the short-circuit fault-tolerant control strategy based on the injection of current to achieve independent suppression of phase loss and short-circuit two negative effects.In addition,the traditional fault-tolerant control is difficult to use the reluctance torque of the motor,and the space vector injection and virtual signal injection maximum torque current ratio(MTPA)control are proposed,and extended to open-circuit and short-circuit fault-tolerant operating states,which effectively improves the torque output capacity and operating efficiency of the motor in open-circuit and short-circuit conditions.The main research content of this paper includes the following aspects:(1)In view of the single-phase open circuit and double-phase open circuit faults of RTI-PMFT motor,construct the mathematical model and the fault-tolerant reduced-order transformation matrix under faults,find out the distribution rules of fault-tolerant voltage vectors,space voltage vector switching sequences and calculation methods of action time under faults,and propose SVPWM open-circuit fault-tolerant drive technology;(2)In view of the single-phase short-circuit,double-phase short-circuit and phae to phase short-circuit faults of RTI-PMFT motor,according to the torque ripple under the motor fault,the short-circuit influence is divided into the fault phase open circuit and the short-circuit phase current.According to the principle of constant magnetomotive force,the short-circuit fault-tolerant control strategy based on the injection of current is proposed;(3)In view of the low efficiency of electric energy utilization under RTI-PMFT motor open-circuit faults and short-circuit faults,by injecting the voltage space vector signal,the magnetic flux after the open-circuit fault produces corresponding disturbances,and the MTPA point is found by the differential relationship between the flux linkage and the current;While virtual signal injection MTPA control uses the differential relationship between torque and current at the MTPA point to find the MTPA point by constructing a mathematical model of torque,and injects the current angle signal to find the MTPA point;Finally,using MATLAB tools performs theoretical verifications;(4)The experimental platform based on d SPACE is built,and the experimental prototype RTI-PMFT motor is introduced.Finally,the fault-tolerant control strategy proposed in this paper is experimentally verified to demonstrate the accuracy and feasibility of the algorithm.