New fully soft switched bi-directional converter for Hybrid Electric Vehicles: Analysis and control

This paper presents a novel fully soft switched bidirectional PWM dc-to-dc. Providing soft switching conditions for all elements and minimizing the semiconductor elements are two of the most important properties of this converter. The proposed bi-directional converter is inserted as an interface circuit between DC bus and battery in a Hybrid Electric Vehicle to control the charge and discharge current. This converter is used to act as a boost converter during motoring operation to drive the traction motor for high speed and high torque, and as a buck converter to capture the regenerative braking energy to charge the battery. Theoretical analysis for both buck and boost modes are presented and simulation results confirm the theoretical analysis. Finally, MATLAB software is used to obtain the simulation results of the converter control based on the state of charge of the battery for both buck and boost modes.