基于电荷平衡的三电平中点电位寻优控制

Three-level Neutral Point Potential Optimization Control Based on the Balance of Charge

针对中点箝位(NPC)三电平逆变器存在的中点电位不平衡问题,通过分析研究不同开关状态对中点电位的影响,提出了一种基于电荷平衡的NPC三电平逆变器中点电位寻优控制方法,通过寻优计算出最优的开关序列及复用矢量作用时间参数,使得在一个采样周期内流入中点的电荷量与直流母线电容偏差的电荷量相等,达到控制中点电位平衡的目的。通过实验结果验证了控制方法的可行性和中点平衡的有效性。

In order to figure out the unbalance problem of the neutral point potential in neutral point clamped （NPC） three-level inverter, based on the balance of charge, a novel neutral point potential optimization control algorithm is proposed by analyzing different switch states＇ impacts on the neutral point potential.In this algorithm,the optimal switch sequence and multiplex vector operation time parameter can be obtained by the optimal calculation, ensuring that the charge flowing into the midpoint and the charge deviation of DC capacitor are equal in a sampling period.Thus,the goal of controlling the balance of the neutral point potential can be achieved.The feasibility and effectiveness of the method are verified by experimental results.