A Reconfigurable Bidirectional DC–DC Converter With Integrated Battery Heating for Electric Vehicle Applications
Ramana Manohar Reddy, Moumita Das
Abstract
A reconfigurable bidirectional dc–dc converter with integrated battery heating and power delivering capability for electric vehicle (EV) applications is proposed in this article. The EVs are primarily powered by lithium-ion batteries but the batteries generally suffer from considerable capacity degradation at subzero temperatures. This causes a sufficient reduction in EV's driving range and operational capability. Such a problem can be solved by maintaining battery temperature to a suitable level. In the proposed system temperature is maintained at a suitable level by an isolated resonant converter with bidirectional power handling capability. The proposed resonant network provides internal ac heating, which is more efficient compared to external heating. This resonant network can also operate in both the LLC and LLCC modes to provide a wide voltage gain during the bidirectional power transfer. The resonant network helps the converter to operate efficiently in a wide voltage range due to its soft-switching capability. Additionally, the LLCC network provides overcurrent protection due to infinite impedance at the resonant frequency. The analysis and simulation result shows wide voltage regulation along with internal battery heating capabilities. A 1-kW laboratory prototype is developed in the laboratory to verify the operation of the proposed system.