A dc to dc multilevel modular capacitor clamped converter with electrical grounding isolation and bidirectional power flow for a dc microgrid application

Abstract

A dc to dc multilevel modular capacitor clamped converter (M 2C 3) with electrical grounding isolation and bidirectional power flow for a dc microgrid application is proposed in this paper. The principle of this particular M 2C 3 is based upon volt-sec balance of capacitors connected as a modular cell in the circuit so that the M 2C 3 can be similarly operated as a dc transformer. The M 2C 3 can be interfaced between a battery and a dc grid. Moreover, two M 2C 3 can be interfaced using a high frequency transformer in order to achieve grounding isolation and exchange energy between M 2C 3. The transferred energy would provide the fault tolerance ability in the case of a M 2C 3 is malfunctioned. Both grounding isolation and bidirectional power flow are one of key functions for dc microgrid applications. The simulation study is performed using PSIM 9.0. Also, the 3-kw prototype is developed to investigate the notion for a dc microgrid application. © 2012 IEEE.