一种基于空间矢量的脉冲宽度调制方法与实验研究

终端级联式五电平逆变器是将两台三电平逆变器的输出终端通过开绕组电机级联而成,针对终端级联式五电平逆变器中存在的共模电压和中点电位平衡问题,研究了一种空间矢量脉冲宽度调制(SVPWM)策略。该方法完全采用零共模电压矢量来消除电机端共模电压;与传统二极管钳位型三电平逆变器相比,所采用的零共模电压矢量对直流侧中点电位的影响更为复杂,基于此采用一种平衡因子控制法来平衡中点电位。仿真和实验结果表明,该方法能完全消除共模电压,较精确地控制中点电位平衡。

A Method and Experimental Research on Pulse Width Modulation Based on Space Vector

Terminal cascade five-level inverter is cascaded through open-end winding induction motor with two three-level inverter output terminals. For the problems of common-mode voltage and neutral-point potential existed in terminal cascade five-level inverter, a space vector pulse width modulation (SVPWM) strategy is researched. Zero common-mode voltage vectors are only adopted to eliminate common-mode voltage of the system in this method. Compared with the vectors in conventional neutral-point clamped three-level inverter, the impact of zero common-mode voltage vectors on the DC-link midpoint potential is more complex. For this reason, a control method based on balance factor is used to control midpoint potential. Simulation and experimental results show that by using the above method, the common mode voltage can be completely eliminated and the neutral-point potential controlled accurately.