基于DSVM异步电动机直接转矩控制系统

针对传统的直接转矩控制系统采用纯积分的电压模型作为磁链观测器，存在着误差积累以及直流偏移，导致电流和转矩的波动问题，提出了一种改进的磁链观测器，该观测器由两个模型组成，开环电流模型用于低速范围内观测磁链，自适应电压模型用于全速范围内观测磁链．对电压模型观测的定子磁链引入一个反馈量，用PI调节器进行误差校正，大大提高了观测的精度．并采用离散空间矢量调制(DSVM)的方法，提高异步电机的直接转矩控制动态性能．在保留传统直接转矩控制(DTC)动态性能的情况下，提高了电机的低速转矩，并减小了转矩脉动和电磁噪声，仿真和试验结果验证了该策略的可行性．

Direct torque control system for asynchronous motor based on DSVM

Direct torque control uses the pure integral voltage model for torque observation. The problems of accumulate error and direct current excursions will cause the fluctuations of current and torque. A modified model of flux observation is put forward. It is composed of two models. The open loop current model uses flux observation in low speed range. The self-adaptation voltage model uses flux observation in all speed range. A feedback is imported for voltage model to observe stator flux and correct error by using PI adjuster. The observation precision is greatly improved. The dynamic performance of direct torque control system for asynchronous motor is also improved by using discrete space vector modulation (DSVM). Simulation and experimental results prove the validity of this method.