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 (M²C³) with electrical grounding isolation and bidirectional power flow for a dc microgrid application is proposed in this paper. The principle of this particular M²C³ is based upon volt-sec balance of capacitors connected as a modular cell in the circuit so that the M²C³ can be similarly operated as a dc transformer. The M²C³ can be interfaced between a battery and a dc grid. Moreover, two M²C³ can be interfaced using a high frequency transformer in order to achieve grounding isolation and exchange energy between M²C³. The transferred energy would provide the fault tolerance ability in the case of a M²C³ 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.