Analysis and Design of a Isolated Bidirectional DC-DC Converter for Hybrid Systems

Multi-port converter with three active full bridges, two series-resonant tanks and a Multi-winding transformer is proposed. It uses a single power conversion stage with high-frequency link to control power flow between batteries, load and a renewable source such as fuel cell. The converter has capabilities of bidirectional power flow in the battery and the load port. Use of series-resonance aids in high switching frequency operation with realizable component values when compared to existing converter with only inductors. The converter has high efficiency due to soft-switching operation in all Multi bridges. Steady-state analysis of the converter is presented to determine the power flow equations, tank currents and soft-switching region. Dynamic analysis is performed to design a closed-loop controller that will regulate the load-side port voltage and source-side port current.