地铁车辆三电平逆变器主传动系统仿真

三电平逆变器较两电平逆变器具有输出波形好、脉冲频率低、对器件耐压要求低、输出的谐波分量低等优点，三电平的牵引逆变器在日本和德国的地铁车辆中均已应用。直接转矩控制具有结构简单、转矩响应快以及对参数鲁棒性能好等优点，已广泛应用于异步电动机的调速系统。现提出一种三电平异步电动机直接转矩控制（DTC）系统，将磁链划分为12个区间，通过定子磁链观测和转矩计算，就可以得到使磁链为圆形的18个电压矢量。仿真结果表明，该方法在三电平逆变器供电的异步电动机上有效地实现了基于18矢量法的DTC系统，并能达到较好的控制性能。

Simulation of the Main Drive System Based on Three-level Inverter for Metro Vehicles

Compared with two-level inverter,three-level inverter has a lot of advantages,such as better output wave,lower frequency of the switch pulse,lower demands for voltage resistance of devices,lower output harmonic content.Three-level traction inverter have been applied to metro vehicles in Japan and Germany.For its simple structure,quick response of motor torque and better robustness of system parameter,direct torque control have been extensively applied to speed regulation system of asynchronous motors.A new theory which is the induction motor direct torque control system based on three-level inverter is brought forward,in the theory flux is partitioned to twelve intervals,eighteen voltage space vectors which make flux round from the observation of flux and calculation of torque is can be deriven.The simulation results show that,the induction motor direct torque control system based on three-level inverter in this paper have been implemented effectively for its eighteen voltage space vectors,what 'more,the system 's control capability is very good.