新型异步电动机直接转矩控制系统仿真

针对基于直接转矩控制的异步电动机运行时存在较大的电流及转矩脉动问题，提出一种用新型逆变器减小转矩和电流脉动的方法，在原有普通逆变器的基础上增加一个Boost电路，使逆变器有三种不同的输出电压，形成十二电压矢量，定子磁链轨迹更接近圆形。仿真结果表明：改进后系统使逆变器开关频率减小，损耗降低，转矩有明显的改善。

Simulation of a new kind of direct torque control on asynchronous motor

In view of the problem of relatively great current and torque ripple of the asynchronous motor based on direct torque control when it is running ,a new method is put forward, using a new kind of inverter to reduce the torque of the inverter and current ripple. Applying a boost circuit based on the common inverter, the inverter can produce three levels of output voltage and create twelve voltage vectors in turn, thus resulting in less current harmonics and makes the flux trajectory closer to a circle. The simulation results show that the improved control system significantly reduces the torque ripple, current ripple and effectively decreases the inverter switching frequency.