Research On Fault Tolerant Control Algorithm Of Five-phase Motor Based On H-bridge

With the development of China's aerospace technology,the new generation of launch vehicles has put forward higher requirements for the reliability of the servo system.It is hoped that the system can still operate reliably under the condition of failure occurrence.This paper focuses on the application of fault-tolerant technology in electromechanical servo system..In this paper,the fault-tolerant motor body is realized by the winding redundant five-phase motor scheme.The characteristics of the five-phase permanent magnet fault-tolerant motor are thoroughly analyzed in detail.It is clear that the fault-tolerant motor must be embodied with the ability of electrical isolation,physical and thermal isolation,magnetic isolation and suppression of short-circuit current.The isolation requirement of the motor is implemented by a single-layer concentrated winding,a wound-toothed winding,an H-bridge power supply,and an increase in the leakage inductance of the slot.Through the analysis of the constraints of motor-use-conditions,power density,torque fluctuation,control resources,etc.,the motor solution is acknowledged by the high temperature NdFeB-used as the permanent magnet material,Halbeach-used as magnetization mode and the main characteristics are featured by five-phase ten-slot twelve-pole single-layer centralized winding.The fault-tolerant motor can realize fault-tolerant operation depending on its control algorithm.The control algorithm of fault-tolerant motor is divided into control algorithm under normal-state and control algorithm under malfunction-state.In this paper,the mathematical model of five-compatible motor is established,and the voltage space vector control algorithm based on H-bridge in two normal states(Adjacent two-vector method and Adjacent four-vector method)is derived.The algorithm simulation analysis is performed by the platform of Matlab/Simulink.The merits and disadvantages of the two algorithms are fully compared.The voltage space vector algorithm of adjacent four vectors is selected as the control algorithm under normal state of the fault-tolerant motor.Fault diagnosis is to quickly detect the occurrence of faults at the beginning of the malfunction,and to achieve the resection and isolation of the fault-phase,providing reference for system decision,avoiding the further expansion of the fault,and is also the key link of the system fault tolerance algorithm.In this paper,the fault characteristics of fault-tolerant motors are analyzed.It is clear that the motor faults are mainly open-circuit faults and short-circuit faults.The fault diagnosis methods are proposed for the two kinds of fault.The fault-tolerant algorithms for the two faults are derived and finite element simulation analysis is carried out to realize Validation of the algorithm.For the control of fault-tolerant motors,the basic requirements are fast torque response,high precision and small fluctuations.The key is to achieve high-performance control of the instantaneous torque of the motor.This paper proposes two control systems based on Id=0: single space vector control and dual space vector control.During the normal-state,the motor adopts single space vector control based on voltage space vector algorithm;during the malfunction-state,the motor will adopt double space vector control based on current hysteresis algorithm.This paper simulates and analyzes the control system in two states to verify the effectiveness of the fault-tolerant control scheme.Finally,the experiment was carried out,and the experimental platform was built to verify the five-compatible motor control algorithm based on H-bridge.Through the experimental verification of the motor no-load,load-bearing operation,fault simulation experiment,etc.,the experimental results were analyzed to prove the five-phase fault-tolerant motor designed in this paper can operate stably under one-degree fault conditions under the control of fault-tolerant algorithms.