一种软开关交错式三电平逆变电路的研究

Study on a Soft-switching Interleaved Three-level Inverter

通过在传统三电平逆变电路的上、下功率管上各并联一个交错式工作的功率管,构成一种输入输出纹波电流倍频的交错式三电平逆变电路。描述了该电路的PWM方式,通过在各交错并联的功率管支路上串联一个限流电感,实现了交错并联各功率管的零电流开通,并降低了续流二极管的反向恢复电流。阐述了电路各阶段的工作原理,分析了限流电感值的影响及设计问题。同理推导得出另一种软开关交错式NPC逆变电路。设计了一台2kVA的样机,实验波形验证了理论分析的正确性。

By adding an interleaved parallel power semiconductor at the upper and lower location in the traditional three-level inverter,an interleaved three-level inverter is realized with input and output double-frequency current and its PWM method is proposed.By inserting a limiting-current inductor in the interleaved power semiconductor branch,the interleaved power switches can realize zero-current turn on and the reverse recovery current of freewheeling diode is reduced.The theory of each operating stage is elaborated.The affect and design of the limiting current inductor are analyzed.Using the same theory,another soft-switching NPC inverter is deduced.A 2 kVA laboratory prototype is produced and the test wave-forms verifiy the correctness of the theory.