Research On Fault Tolerant Permanent Magnet Motor System Based On Half-bridge Inverter

Nowdays, electric actuators which core contains power inverter and drive motor have been widely used instead of traditional hydraulic systems that make the structure of aircraft system more compact, faster response, higher actuator control efficiency and reduce the energy consumption. Therefore, to design a fault-tolerant motor and its control system are increasingly becoming the key technology of more electric aircraft systems. Redundancy and fault-tolerant technology are the two stages of its development. Compare with redundancy tochnology which is widely used at present, the fault-tolerant permanent magnet motor (FTPMM) has lots of excellent features such as high utilization rate, small size and there are no current balance problems. It represents the direction of the current international developments and has an unparalleled vitality.At the beginning of this thesis, analysis and introduction of fault isolation and fault-tolerant features of FTPMM have been given.This thesis proposed a novel half-bridge inverter of FTPMM system for the first time.Compare with the H-bridge inverter, the new topology not only has the fault-tolrant characteristics, but also reduce the number of power switching devices which improve the reliability of the motor system as a result. In this thsis, a mathematical model of six phase FTPMM and the analysis of the principle of optimal torque control strategy have been given.On these basis,we creat the six phase FTPMM control system model based on half-bridge inverter which using the MATLAB/Simulink software. In addition, short fault simulations and open fault simulations have been made based on this model.In this thesis, a full digital control system of six-phase FTPMM based on half-bridge inverter has been given. The system including TI's TMS320LF2407 DSP as the control core, CPLD-M4A5 as the fault integrated unit and Intelligent Power Module (IPM) as the main power unit. And the control software has been made which using the assembler language. On this basis, short circuit fault experiments, open circuit fault experiments of IGBT and motor winding have been taken when at a given speed 1000rpm and a given torque 1N ? m situation. Experiment results show that the feasibility and effectiveness of the FTPMM system which based on the novel half-bridge inverter.In last chapter, a research of diagnostic methods of FTPMM system which based on the half bridge inverter has been made.After summarize the fault status of FTPMM system, a diagnostic method has been given. And experiments have been made at a given speed 1000rpm and a given torque 1N ? m situation. The results verify the accuracy of the diagnostic method.