A high-performance bidirectional DC-DC converter for DC micro-grid system application

Abstract

This paper presents a high efficiency dual-half-bridge bidirectional DC-DC converter for DC micro-grid system applications. The operating principle and design consideration of the studied bidirectional converter are discussed. The zero-voltage-switching features and an adaptive phase-shift control method can be achieved under wide-range load variations. When power flow through from DC_BUS side to the battery side. A three-stage charging method is designed to meet the fast-charging demand and prevent battery overcharging to prolong the life-time of LiFePO4 batteries. Otherwise, a digital-signal-processing (DSP) control IC is used to realize the power flow control, DC_BUS voltage regulation and battery charging/discharging of the studied bidirectional DC-DC converter. A 10kW laboratory prototype converter with E-CAN communication function is built and tested for DC micro-grid system applications. The experimental results are shown to verify the feasibility of the proposed scheme. High efficiency performance can be achieved by the studied adaptive phase-shift control method and zero-voltage switching features. The measured Peak efficiency of the prototype converter expect to higher than 98% under discharging mode and charging mode.