A Novel Semi-Isolated Three-Port dc-dc Power Converter with Soft Switching Technique for Hybrid Energy Storage Applications

Tendency to achieve high power density in power converters brought multi-port converters into the center of attention. These converters, if designed properly, benefit from fewer active and passive components. Therefore, multi-port converters are expected to have higher power density and potentially lower cost compared to their counterparts. This paper presents a novel semi-isolated three-port dc-dc converter for hybrid energy storage systems. Moreover, a novel control method is applied to the proposed three-port converter to guarantee soft switching at different modes of operation. This control method uses both fixed and variable frequency PWM methods. Variable frequency PWM is employed to achieve boundary current mode operation for one port which enables optimum design for the inductor in the mentioned port. Furthermore, a 1.5kW model of the proposed converter, suitable for low power electric vehicles, such as electric motorcycles, bikes, and golf cats, has been simulated. Simulation results demonstrate the capabilities of the proposed three-port converter and effectiveness of the presented control method.