基于软开关MERSPFC电路拓扑及性能分析

Topology and Performance Evaluation Based on Soft-switching of MERS PFC Circuit

由于电流连续型功率因数校正(CCM PFC)电路能够最大限度地减少网侧电流谐波以及提高网侧的输入功率因数,被广泛地应用于各种功率变换器的前端电路结构中。文中基于电感电容谐振的软开关技术,提出了一种新型的CCM PFC电路拓扑——磁能回复开关型功率因数校正(MERS PFC)电路。通过合理的控制,该电路不仅具有较高的输入功率因数,同时实现了全功率开关器件的零电流开通及零电压关断。其次,文中对所提出的电路拓扑建立电气模型,详细分析了每一个开关周期内的电压电流工作特性,推导出其升压比计算公式,仿真验证了建模以及公式推导的正确性。在此基础上,文中详细讨论了所提出的MERS PFC电路的工作性能。计算表明,在开关频率为10 kHz时,该电路的功率器件损耗比传统boost PFC电路减少了约39%,具有更高的效率。同时,在同样的参数条件下,和传统的boost PFC电路相比,所提出的新型结构具有更高的升压能力。最后,实验结果验证了所提出的MERS PFC电路及其软开关工作特性。

Owing to the fact that continuous current mode power factor correction(CCM PFC)circuit can be used to sig-nificantly reduce current harmonics and improve the power factor on grid-side,it is widely used in the front-end circuitof different power converters. Based on the soft-switching technology of LC resonant circuit,a novel CCM PFC circuit to-pology,i.e.,a magnetic energy recovery switch power factor correction(MERS PFC)circuit,is proposed in this paper.First,through proper control,this circuit not only possesses a high input power factor,but also achieves zero currentturn-on and zero voltage turn-off on a full power switching device. Then,an electrical model is established for the pro-posed circuit,and the voltage-current operation characteristics in each switching cycle are analyzed in detail. More-over,a boost ratio formula is proposed,and simulation results prove the validity of modeling and derived formulas. Onthis basis,the operation performance of MERS PFC circuit is discussed. Calculation results show that compared withthe traditional boost PFC circuit,the loss of the proposed circuit is reduced by about 39% at the switching frequency of 10 kHz,indicating a higher efficiency;meanwhile,it has a higher boost capacity with the same parameters. Finally,experimental results verify the proposed MERS PFC circuit and its soft-switching operation characteristics.