NPC/H桥逆变器直流侧电容电压平衡研究

摘要

Aiming at the DC-side capacitor voltage imbalance of neutral point clamped(NPC)/H bridge inverter,a novel algorithm is proposed to balance the DC-side capacitor voltages of three phases based on the traditional space vector pulse width modulation(SVPWM) algorithm.In the algorithm,g-h coordinate frame is used to confirm the position of the reference voltage and then select the suitable vectors.What's more,the improved algorithm adds adjustment factors to adjust the working time of balance vectors to implement the control of midpoint potentials of three phases.The experiment demonstrates the proposed algorithm has a very good effect on the balance of DC-side capacitor voltages and strong dynamic response capability.%针对中点箝位(NPC)/H桥逆变器直流侧电容电压的不平衡问题,基于传统空间矢量脉宽调制(SVPWM)算法,提出了一种平衡三相直流侧电容电压改进型控制算法.该算法利用g-h坐标系确定参考电压位置,选择相应的位置矢量及平衡矢量并优化矢量合成序列,同时加入调节因子调整平衡矢量作用时间,从而实现对直流侧电容中点电位偏移的抑制.实验表明所提出的改进型SVPWM算法能有效平衡三相直流侧电容电压并且具有较强的动态响应能力.