摘要
针对中点钳位型(NPC)三电平逆变器中点电位波动问题,在三矢量四状态合成方法的基础上,提出一种精细分区控制的中点电位平衡策略。在低调制度下,对占空比分配因子进行限幅,尽量控制中点电流为零。在高调制度下,通过对比最值电流法和分配因子法分区结果的不同,将工作区域划分为可控区域(CI)、不可控区域(UI)和存疑区域(DI),并对DI区域按中点电流控制效果进行归属判定,在不增加开关频率的情况下,尽可能将中点电流的绝对值控制为最小,实现减小中点电位波动的目的。仿真和实验结果验证了所提策略在降低开关频率的同时,可有效抑制中点电位的波动。
To solve the problem of neutral point potential fluctuation of neutral point clamped（ NPC） threelevel inverter, a meticulous partition control strategy is proposed based on the three vectors and four states synthetic method. In the low modulation degree,the amplitude of the duty cycle distribution factor is limited in order to eliminate the neutral point current. In the high modulation degree, through analyzing the judgment difference between extreme current value method and distribution factor method,the working area is divided to controllable interval（ CI）,uncontrollable interval（ UI）,and doubtful interval（ DI）. The adscription of DI is analyzed based on the control effect of the neutral point current,which minimize the neutral point current without increasing the operating frequency. By these,the neutral point potential fluctuation can be decreased with a low switching frequency,which is verified by the results of the simulations and experiments.
出处
《电工技术学报》
EI
CSCD
北大核心
2015年第19期144-152,共9页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51207104)
天津市高等学校科技发展基金计划项目(20140414)资助
关键词
中点钳位型三电平逆变器
中点电位平衡
三矢量四状态调制
精细分区控制
NPC three-level inverter
neutral point potential balance
three vectors and four states modulation
meticulous partition control
