单级三电平交流斩波器的控制策略研究

Control Strategy of Single-stage Three-level AC Chopper

提出了新颖的单级三电平交流斩波器的电路结构及拓扑族。该电路结构由三电平变换器以及输入、输出滤波器构成,能够将一种不稳定的、劣质高压交流电直接斩波成稳定或可调的优质正弦交流电。其拓扑族包括Buck式、Boost式、Buck-Boost式等结构。该类交流斩波器适用于高输入电压AC/AC变换场合,具有单级功率变换,拓扑简洁,双向功率流,功率开关电压应力可降低等优点。针对箝位电容电压控制问题,提出箝位电容电压和输出电压瞬时值双反馈控制策略。实验结果证明了该类交流斩波器及其控制策略的正确性及先进性。

Circuit structure and topological family of novel single-stage three-level AC choppers are proposed.The cir- cuit configuration is constituted of three-level converter,input and output filters,which can chopper unstable high voltage AC voltage with high THD into stable or adjustable sinusoidal voltage with low THD.The proposed AC chop- per,which is suitable for high input voltage AC conversion field, has such advantages as single-stage power conver- sion,concise topologies,bi-directional power flow,lower voltage stress of power switches,three-level voltage wave- form, low THD of output voltage, strong adaptability to various loads, etc.For the voltage control of the clamp capaci- tor,transient double voltage feed-back control strategy is presented and investigated.The correction and advancement of the AC choppers and control strategy are well verified by test results.