Single-phase Open-circuit Fault-tolerant Control For Multi-mode Operation Of Dual Five-phase Permanent Magnet Motor

Multi-phase PM motors have high torque density,high efficiency and high fault tolerance,and have been widely studied and researched in highly reliable fields such as electric vehicles,naval propulsion and aerospace.Compared with the traditional multi-phase motor,the Multi-Operation mode Dual Five-Phase PM motor(MODF-PM motor)has two stators and two sets of five-phase stator windings,and can operate in three operating modes: main drive/auxiliary drive alone,main drive and auxiliary drive simultaneously,and auxiliary drive mixed excitation.The MODF-PM motor is capable of operating in three modes of operation:main drive/auxiliary drive alone,main drive and auxiliary drive simultaneously and auxiliary drive mixed excitation.This paper first analyses the operating principle of the new MODF-PM motor,establishes the mathematical model for its various operating modes and proposes the Carrier-Based Pulse Width Modulation(CPWM)algorithm for its normal operation.In addition,the fault-tolerant control strategy is proposed for the MODF-PM motor,taking full advantage of the characteristics of the MODF-PM motor,to achieve a fault-tolerant control in which the amplitude of the phase current of the faulty stator winding remains constant before and after the fault.In addition,the results of fault-tolerant operation in multiple modes are compared to determine the operating modes for different operating conditions in terms of copper consumption,enabling mode switching during fault-tolerant operation and improving the operating efficiency while enhancing system safety.The main research of this paper includes the following aspects:(1)The structure and characteristics of the MODF-PM motor are analysed,and three modes of operation are proposed;the mathematical models of the motor under different modes of normal operation in the natural and rotating coordinate systems are derived;the decoupling model of the motor under a single-phase open-circuit fault in the main drive is derived using the fundamental wave reduced-order matrix.(2)The principles of Space Vector Pulse Width Modulation(SVPWM)and CPWM modulation are introduced;the modulation method is analysed in the context of the structure of the MODF-PM motor,and the CPWM modulation method under the closed loop of the third harmonic current is proposed,and a simulation model is built using Simulink to verify the feasibility of the algorithm.The algorithm is also used to build a simulation model to verify the feasibility of the algorithm;various modes of operation of the MODF-PM motor are introduced,and the corresponding torque equations and current distribution strategies are given.(3)The fault-tolerant algorithm for MODF-PM motors with constant current amplitude before and after a single-phase open-circuit fault in the main drive is proposed to address the problem of increasing fault-tolerant current amplitude in conventional five-phase motors;the minimum copper consumption control strategy for the internal and external stator windings under single-phase open-circuit fault-tolerant control is also proposed,and the feasibility of the algorithm is confirmed by simulation studies using Simulink.The MODF-PM motor drive system based on the RTU-Box204 platform is designed to experimentally validate the fault-tolerant control strategy proposed in this paper,and the experimental results prove the accuracy and feasibility of the proposed algorithm.