五电平逆变器直接转矩控制算法改进

An Improved Five-level Inverter Direct Torque Control

针对磁链和转矩双闭环控制的直接转矩控制系统在获得所需电压空间矢量时需要复杂的坐标变换,本文构建了级联型五电平逆变器异步电机直接转矩系统,提出了一种改进的获取电压空间矢量的方法,直接在αβ坐标系下对磁链和转矩进行调节,该方法能够有效减小磁链和转矩脉动,并且能够减小计算机实时的计算量。在Matlab/Simulink软件平台上搭建了级联型五电平逆变器异步电机直接转矩控制系统模型,采用60°坐标系下的SVPWM调制算法,对改进的快速获取电压矢量的方法进行验证,仿真表明,该算法在减少计算机工作量的同时,获得了较好的磁链轨迹和转矩响应曲线。

This paper presents a five-level cascade inverter direct torque control system for asynchronous AC motor.A new method for selecting voltage vector is purposed. By the application of this new method,the torque and flux linkage of motor can be adjusted in αβ coordinate frame directly. Thus,the ripple of torque and flux linkage can be reduced obviously,and the calculation of Matlab can be decreased. A model of five-level cascade inverter direct torque control system is constructed for simulation in the Matlab/Simulink. A space vector pulse width modulation（ SVPWM） algorithm under 60° coordinate frame is applied in the model to verify the new method. The results of simulation show that the application of this method can reduce the workload of Matlab. Additionally,better torque response and trajectory of flux can be got.