Investigation Of Director Torque Control System For A Fault-Tolerant Permanent Magnet Motor Drive With Redundancy

The electric drive system has been widely used in many areas due to its advantages such as high efficiency, flexible control and fast response. Motor and control system is the core part of the electric drive system and its reliability is one of the important specifications to scale the performance of the entire system. In order to effectively improve the reliability of the motor and control system, the fault tolerant motor and control system has become a hot research topic. This paper combines redundancy and fault-tolerant technology to investigate Director Torque Control (DTC) system for a Fault-Tolerant Permanent Magnet (FTPM) motor drive with redundancy.Firstly, the structure and the features of a three-phase FTPM motor are introduced. Then the mathematical models for this motor drive are established. On this basis, a dual redundant fault-tolerant permanent magnet motor drive system is constructed. Secondly, the basic theory used in the direct torque control technology for FTPM motor is analyzed. Through studying the distribution of the phase voltage space vector in the normal state and one phase open-circuit fault state, the fault-tolerant strategy of a three-phase fault-tolerant motor drive based on DTC is proposed under one-phase open-circuit fault condition. Finally, the structure block diagram of a dual redundant FTPM motor control system is designed and the operation modes of this system under healthy condition, the controller fault and one-phase open-circuit fault conditions are provided.To verify the correctness and the feasibility of the control strategy, the simulation models for proposed system based on MATLAB/SIMULINK are built and the simulation verification was made. After that the experimental setup based on TMS320F2812is built and the software is written and debugged in CCS3.3environment. The hardware of this setup includes main circuit module, drive and isolation module and detection module. Experimental results show that the system can continue to operate under controller fault and one-phase open-circuit fault conditions and output the same magnetic torque as in healthy condition. The proposed system realizes the fault-tolerant control.