有源中点钳位逆变器的损耗均衡和效率优化策略

Loss Equalization and Efficiency Optimization Strategy of Active Neutral Point Clamped Inverter

针对有源中点钳位(ANPC)逆变器,基于开关损耗分配的基本原理,建立开关器件的损耗估计模型,提出一种主动调节损耗分布的方法,通过合理分配不同开关器件来承受开关损耗,调节各模态的起始时间和持续时间,尽可能地减小各开关器件之间的损耗差异,并扩展到变功率因数角的场合,该方法实施简单且有效。此外,当桥臂输出电压被钳位到直流中点时,通过对驱动时序的调整和重新构造,使两条零电平回路同时导通(TZCC)进行续流,有效地减小了导通损耗,进一步提升变换器效率。较传统的损耗均衡或效率优化单一目标上,所提方法在损耗均衡的同时又能兼顾其运行效率,充分地发挥出ANPC逆变器的优势。最后,通过仿真和实验验证了所提策略的有效性。

For active neutral point clamped(ANPC) inverter, loss estimation model of power devices is built based on the principle of switching loss distribution, and an online adjustable loss distribution method is proposed to minimize the loss difference between every power device, by means of reasonably allocating different switching devices to undertake the switching loss and regulating the starting time and duration time of each mode. The method is deduced in detail and extended to the cases of variable power factor angles, which shows simple implementation and good effectiveness. Moreover,when the terminal voltage is clamped to neutral point, two zero-level clamped loop conducting(TZCC)is utilized for freewheeling through the reconstruction of the driving signals, therefore, conduction loss is decreased and the efficiency is further improved. Compared with the traditional single objective of loss equalization or efficiency optimization, the proposed method can achieve them both, so as to give full play to the advantages of ANPC inverters. Finally, the effectiveness of the proposed strategy is verified by simulation and experiments.