Bidirectional CLLC Resonant Converter Employing PLC Capability and EM Noise Reduction Technique for Small-Sized ESS Application

Abstract

An energy storage system (ESS) requires high reliability with low electromagnetic (EM) interference, communication capability between ESS applications, and bidirectional power conversion for charging and discharging operations. However, a conventional ESS separately has power converters, communication devices, and large-sized EM interference filters for its stable operation. In this paper, a current-fed CLLC resonant converter employing asymmetric pulse-width modulation and spread spectrum modulation are proposed to obtaining three functions bidirectional power conversion with tight output voltage regulation, EM noise mitigation, and power line communication (PLC) capability among ESSs, simultaneously. It can improve the cost-effectiveness, system’s form factor, and communication flexibility. The proposed integration of three functionalities has design constraints on the implementation of each function. Design methodologies of power stage and control algorithm are also proposed for achieving the simultaneous operation of each function. The performance of the proposed converter and control algorithm is verified through a 20-W prototype converter.