三相交错并联三电平DC-DC变换器的ZVS控制

ZVS Control of an Interleaved Three-phase Three-level DC-DC Converter

非隔离DC-DC变换器具有高效率、低成本、小体积的优势,广泛应用于大功率储能系统。文中研究一个通过近似临界导通模式(near critical conduction mode,near-CRM)实现零电压软开关(zero-voltage switching,ZVS)的三相交错并联三电平DC-DC变换器,以减小开关损耗和电感体积。首先,详细地分析该变换器区别于传统两电平交错并联DC-DC的电感电流纹波特性,并成功推导出纹波峰峰值解析表达式。然后,提出通过变开关频率控制纹波峰峰值和纹波反向电流的方法,以实现全负载范围的near-CRM和ZVS模式。最后,搭建一台基于IGBT器件的15kW实验样机,验证了电感电流纹波分析和提出的控制方法,其最大效率98.02%。

The non-isolated DC-DC converters are widely used in high power energy storage systems featuring their high efficiency,low cost and small size.This paper studied an interleaved three-phase three-level DC-DC converter with zero-voltage switching(ZVS)by near-critical conduction mode(CRM)operation in order to reduce the switching losses and the inductor size.The paper first analyzed the unique characteristics of the inductor current ripples for the topology.Even though the ripples are more complicated than those of the conventional 2-level 3-phase interleaved topologies,its peak-peak ripple current expression is successfully derived.Then,a variable switching frequency control was proposed to actively control the peak-peak current and the reversed polarity peak current,so that the near-CRM and ZVS modes were maintained throughout the operating range.Finally,an IGBT-based 15kW interleaved three-phase three-level DC-DC converter prototype with the maximum efficiency of 98.02%was constructed to verify the proposed current ripple analysis and proposed control method.