为了寻求进行系统可靠性设计的依据,对直接转矩控制异步电机驱动系统中逆变器故障工况进行研究.通过对直接转矩控制原理的分析,指出系统运行工况的影响因素;对逆变器最常见的功率开关短路与开路故障工况进行仿真研究,其中功率开关短路故障工况指系统采取截止故障开关互补开关或截止所有开关两种保护方案之后的工况.仿真结果表明,短路故障后尽管采取了保护方案,系统仍会出现大的机械和电流冲击,其中截止所有开关的保护方案相对较优,但此方案下电流和转矩的最大值仍超过正常运行时额定值的10倍以上;在发生功率开关开路故障时,故障相电流只有半个周期,转矩有低频脉动,但系统仍可继续短时运行.%In order to seek evidence for system reliability design, investigation of inverter fault mode behavior for direct torque control (DTC) induction motor drive system is done. Based on analysis of the principle about DTC, influence factors of operation behavior about the system were pointed out. Simulation investigation about power switch short circuit and open circuit, which are the most familiar fault modes of inverter, was implemented. Short circuit mode behavior refers to the situation when the system adopted two protect schemes, of which one is that the complementary switch of faulty switch is turned off, and another is that all other switches are turned off. Simulation results show that the system has an enormous impact on mechanism and electrical current at power switch short circuit mode, though the protect schemes were adopted. The scheme of turning off all switches is relatively optimal. The impact on mechanism and electrical current still exceeds ten times of rating value in this scheme. When power switch open circuit fault happens, the current has only half period, and the torque oscillates at low frequency; whereas the system can still run continuously in a little time.
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