Digital Control of a Bidirectional DC/DC Switched Capacitor Converter for Hybrid Electric Vehicle Energy Storage System Applications

This paper presents the analysis and novel controller design for a hybrid switched-capacitor (SC) bidirectional DC/DC converter, applicable for electric and plug-in hybrid electric vehicles (HEV/PHEV) energy storage system (ESS) applications, based on power of traction motor and battery current gradient. Features of voltage step-down, voltage step-up, and bi-directional power flow are integrated into a single circuit. The developed novel control strategy enables simpler dynamics compared to a standard buck converter with input filter. Experimental results show, the proposed converter topology enables good regulation capability, low EMI, lower source current ripple, ease of control, and continuous input current waveform in both buck as well as boost modes of operation.