A gridded modular bidirectional high voltage gain soft-switching DC–DC converter and its multiport expansion

Abstract

Here, a novel modular bidirectional high voltage gain soft-switching DC–DC converter is proposed. The proposed converter named gridded modular high-gain soft-switching DC–DC converter (GMHSC) can achieve wide range expansion of port voltage and voltage gain by gridded filling of modules and achieve voltage and current sharing among these modules. In addition, all semiconductor devices also realize full-load soft-switching operation in both power directions by introducing a simple auxiliary zero-current transaction (ZCT) cell in each module. A distributed control system including a centre controller and localized module controllers is proposed to improve the converter's design flexibility and dynamic performance. Moreover, the GMHSC is able to provide multiple fixed voltage nodes, which makes it suitable to expend to a multiport converter. A 1.6 kW 200 kHz experimental prototype based on SiC device is provided to achieve an efficiency of 97.9% and 97.7% in boost and buck modes, respectively. Furthermore, the input current and output voltage ripples are greatly reduced through interleaved operation of the GMHSC.