改进滞环比较器的永磁同步电动机直接转矩控制

在研究了永磁同步电动机直接转矩控制基本原理的基础上，分析了直接转矩控制方案的特点及不足。理论分析结合仿真均表明。对称的磁链滞环调节使转矩波动较大且超出转矩滞环的宽度，将磁链滞环的宽度设得很窄时，可以减小这种波动，但逆变器的开关频率随之增大。本文在分析这种波动产生原因的基础上，提出对滞环比较器进行不对称上下限的设置以抑制转矩较大的波动和降低逆变器的开关频率。仿真结果表明，该方法使得转矩波动限制在要求内，逆变器的开关频率降低。得到了较好的转矩控制效果。

Direct torque control of PMSM based on modified hysteresis band

The character and the insufficiency of the common control strategy of DTC are analyzed on the basis of studying the principle of direct torque control(DTC) for PMSM.It is found out that there exists a bigger wave of torque while using a symmetrical flux hysteresis band and the wave will be minished if we narrow the width of the flux hysteresis band.This will increase the frequency of the inverter.The output of the hysteresis band is changed to be anisomerous and some available results are given by emulating.It is proved by results that this method can make the wave of torque under control well and reduce the frequency of the inverter.