Considering the nonlinear characteristic of asynchronous machine, a novel approach to direct torque control system of high-voltage high-power asynchronous machine fed was presented using cascaded multilevel inverter. The stator flux increment vector including range increment and phase increment was obtained when the stator flux and machine torque were controlled in a closed way in the stator coordinate. The required stator voltage vector was calculated according to the stator flux increment vector. The stator flux and machine torque were estimated by an adaptive observer. The speed, torque and stator flux controllers were designed by using active disturbance rejection control technique, and these controllers have high robustness. The load disturbance was estimated and compensated by the speed controller, which effectively removed the static tracking error that would be caused by the disturbance without compensation. The results show that inverter switching signals are generated by carrier phase-shifted pulse width modulation method, and thus the torque and stator flux amplitude ripples are reduced. The closed-loop control system has excellent dynamic and static performance.%针对异步电机的非线性特点,设计一种新颖的级联型多电平逆变器供电的高压大功率异步电机直接转矩控制系统.在定子坐标系内对定子磁链与电机转矩进行闭环控制得到定子磁链增量,包括定子磁链的幅值增量和相位增量.由定子磁链增量计算异步电机定子电压矢量,定子磁链和电机转矩采用自适应观测器估计.采用自抗扰控制技术设计速度、转矩和定子磁链控制器,这些控制器具有鲁棒性强的特点.研究结果表明:通过速度控制器对负载扰动进行估计和补偿,消除了负载扰动可能带来的稳态跟踪误差；逆变器的开关信号利用载波移相脉宽调制方法生成,从而减少了转矩和定子磁链幅值的脉动；系统具有良好的动态和稳态性能.
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