基于虚拟矢量的三电平模糊直接转矩控制

基于三电平逆变器空间电压矢量，构造了12个等幅值的虚拟矢量，提出了一种模糊选择虚拟矢量的三电平逆变器直接转矩控制方法。虚拟矢量原则上不引入中点电流，不造成直流侧中点电压波动；等幅值设计与模糊选择能有效减小转矩脉动。中点电压控制通过调整奇数编号虚拟矢量中一对正负小矢量的作用时间实现。该方法的有效性已通过Matlab仿真验证，适用于大容量交流调速系统。

Direct torque control on three-level inverter based on virtual vectors with fuzzy logic

In this paper,12 virtual vectors with equivalent amplitudes are constructed,and a scheme of direct torque control on three-level inverter based on virtual vectors with fuzzy logic is proposed,based on space voltage vector of three-level inverter.The virtual vectors don’t introduce midpoint current in principle,so don’t cause fluctuations to mid-point voltage of DC;equal magnitude designed and selected with fuzzy logic can reduce the torque ripple effectively.The control of mid-point voltage is realized by adjusting the action time of positive and negative small vectors of virtual vector odd-numbered.The effectiveness of the proposed method is verified by Matlab simulation,and suitable for large-capacity AC drive system.