Design and Implementation of High-density Isolated Bi-directional Soft-switching Resonant DC-DC Converter with Partial Power Processing
Yuliang Cao, Minh Ngo, Ning Yan, Yijie Bai, Dong Dong, Rolando Burgos, Agirman Ismail
Abstract
With the increasing demand for energy storage system in transportation and stationary applications, a high-density high-efficient bi-directional dc-dc converter with galvanic isolation and scalable architecture for different battery systems is desired. This paper adopts a 500 kHz high-efficiency isolated bi-directional soft-switching resonant converter with a partial power processing (PPP) architecture for energy storage systems. Compared with existing PPP or two-stage architectures, the proposed resonant converter utilizes a low voltage (LV) buck regulator for battery interface. Due to the LV regulator, dc transformer (DCX) operates at a fixed switching frequency without any additional ac inductor and zero current detection (ZCD) components. To minimize ac loop inductance in the proposed DCX, a two-dimensional (2-D) flux cancelation layout is proposed, which achieves loop inductance of 4.24 nH. The paper presents the analysis of the converter operation, detailed 18 kW converter design of using 1.2 kV silicon carbide (SiC) MOSFETs and 650/150 V gallium nitride (GaN) FETs, achieving efficiency 98.8% and 142 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> power density.