應用于NPC型逆變器的三電平不連續PWM方法

Discontinuous PWM strategy considering neutral-point potential balance for a three-level NPC inverter

摘要: 針對低頻大功率二極管中點鉗位(NPC)型逆變器控制系統的不連續空間矢量脈寬調制原理及控制策略的研究,提出三電平不連續空間矢量脈寬調制方法,相比于傳統三電平空間矢量脈寬調制方法,在相同的開關頻率下,此方法可以顯著降低逆變器的開關損耗.同時,文中對三電平逆變器的中點電壓不平衡問題以及在現場應用中可能出現的PN電平跳變問題進行分析,并提出解決方法.最后,針對本文提出的調制方法做中點電壓的平衡控制,給出對于該算法基于仿真和實驗的驗證.

Abstract: A novel discontinuous space-vector pulse width modulation(DSVPWM) strategy is proposed for a three-level neutralpoint-clamped(NPC) voltage source inverter. Compared with traditional space-vector pulse width modulation(SVPWM),the proposed strategy can largely reduce the switching losses of the inverter at the same switching frequency. Then,solutions to the imbalance of neutral-point voltage and the PN voltage jumps during application are proposed in this paper. At last,the three-level DSVPWM strategy is verified by simulation and experiment.