三电平逆变器的点电压平衡控制

Neutral-point balancing control strategy for three-level neutral-point-clamped(NPC)inverter

为解决电压型逆变器中点电压不平衡问题,分析了中点钳位式(NPC)三电平逆变器的基本原理,介绍了三电平逆变器的SVPWM算法。根据正负小矢量对中点电位的影响提出了两种平衡中点电位的控制策略,并通过设定电压误差滞环把两者结合起来。仿真结果表明,该方法能有效约束三电平逆变器的中点电压。

To solve the unbalance due to neutral voltage in voltage-source inverter, this paper introduces the SVPWM algorism by analyzing the basic theory of three-level neutral-point-clamped （NPC） inverter. The paper presents two kinds of control strategies, based on the impact of the positive and negative space voltage vectors on neutral voltage, and discusses joining them through a hysteresis of voltage. The simulation results show that the strategy can keep the neutral voltage of three-level inverter within given limits.