一种带纹波抑制的交错并联Buck/Boost变换器轻载效率研究

非隔离型交错并联双向Buck/Boost变换器普遍存在轻载效率低的难题。以多相交错并联Buck/Boost变换器Boost模式为研究对象,分别对其工作在DCM和CCM模式下的功率损耗进行综合性分析研究。根据变换器轻载运行时降低频率可以提高效率的原则,提出最优化调频原则,对其不同负载下开关频率进行调整,以达到提高效率的目的。针对降低频率会带来纹波恶化的缺陷,将磁集成技术应用到交错并联双向Buck/Boost变换器,有效改善通道电感电流纹波及输出电压纹波,并给出磁集成后滤波电容优化设计原则,以最大程度减小损耗,提高轻载效率。最后通过仿真和实验验证了理论分析的正确性,为交错并联双向Buck/Boost变换器轻载效率优化提供了新的理论依据,推动了全负载高效率双向Buck/Boost变换器的设计实现。

A Ripple Suppression with Staggered Parallel Buck/Boost Converter Light Load Efficiency Research

The non-isolated interleaving bi-directional Buck-Boost converter is faced with a widespread problem of low underloading efficiency. The Boost model of the multi-phase interleaving Buck/Boost converter is adopted as the research object in this paper, and a comprehensive analysis of power loss is conducted under the DCM and CCM model. According to the principle that efficiency can be increased through reduced frequency during underloading operation of the transformer, and the principle of optimized frequency modulation is put forward to adjust the switching frequency under different loads so as to realize the goal of increasing efficiency. Concerning the defect of worsening ripples caused by reduced frequency, the magnetic integration technique is applied to the interleaving bi-directional Buck/Boost converter to efficiently improve the channel''s inductive current ripples and the output voltage ripples. Besides, the filter capacitor optimized design principle after magnetic integration is given at an attempt to minimize loss and increase underloading efficiency. At last, the accuracy of the theoretical analysis is proved by simulation and experiments, thus providing new theoretical bases for underloading efficiency optimization of the interleaving bi-directional Buck/Boost converter and promoting realization of the full-load high-efficiency bi-directional Buck/Boost converter design.