Research On Fault Tolerant Permanent Magnet Motor Control System Based On Three-phase Four-Leg Inverter

Nowadays, more-electric and all-electric aircraft has become the main direction of developmentin civil aircraft and military aircraft. It reduces the volume and weight, enhanced the response speedand maintainability of the aircraft greatly to using electric actuator to replace traditional hydraulic andpneumatic equipment. Therefore, the key to the development of more electric aircraft is to design anelectric drive system with strong fault tolerance, high output performance and high power density.Fault-tolerant can make the system operate safe and stable under acceptable performance, when oneor more phases fail.Firstly, various fault-tolerant topologys are compared and analysed, and the fault-tolerantpermanent magnet motor (FTPMM) control system based on three-phase four-leg inverter isintroduced. Compared with the system drived by H-bridge topology, the system reduces the numberof tubes greatly and improves the reliability of the system. Fault identification and fault handing hasalso been analyzed when open-circuit or short-circuit fault happen. Then for the failure of the system,three fault-tolerant control methods were proposed, namely the MMF conservation control algorithm,the optimal current control algorithm and the fault-tolerant control methods for space vector SVPWM.The three algorithms can guarantee the system’s output performance before and after the failure, andachieve fault-tolerant control systems. On these bases, we establish the simulation model based onthree fault-tolerant algorithms with MATLAB, and open-circuit and short-circuit fault simulationshave been analyzed also.In this thesis, a digital control system platform of FTPMM based on three-phase four-leg inverterhas been given. The system includes TI’s TMS320F2812DSP as the control core, Lattice’sCPLD-M4A5as the integrated Fault handling unit and Mitsubishi Company’s IPM as the main powerunit. Based on the hardware platform above, the control software procedures were given by Clanguage, including failure identification procedures, control algorithm procedures. Then based on thehardware and software, the system has been debugged.Experimental results verify the feasibility and effectiveness of the three fault-tolerant controlalgorithms.