SiC switch‐based isolated DC‐DC converter for simultaneous charging of Li‐ion batteries of different voltage ratings for low‐ and medium‐power electric vehicle battery charging application

Abstract

SummaryThe use of electric vehicles (EVs) has gained traction in recent years. With the widespread use of EVs in the future, the waiting time before charging will be high due to the use of slow chargers in developing countries. This work proposes a novel DC‐DC converter based on an isolated single‐ended primary inductor converter (SEPIC) and isolated Ćuk converter to enable simultaneous charging of batteries of low‐ and medium‐power EVs. The proposed converter operates without spikes in input and output currents, even during a sudden source disturbance. It can charge one battery at the output voltage level and simultaneously charge two batteries at half the output voltage. Simulation results for open‐loop and closed‐loop operations are provided to validate the converter operation and the simplicity of control. The proposed converter operation has been experimentally validated using a scaled‐down prototype by charging one 48 V lithium‐ion battery and then simultaneously charging two 24 V lithium‐ion batteries. The converter's response is provided to present the novelty and advantages of the proposed converter. The proposed converter uses fewer switches, diodes, inductors, and capacitors. The size of the system is reduced due to the high switching frequency operation of SiC devices. A low‐side gate driver is sufficient for driving the MOSFET, and the control is simple. The proposed converter offers a new and simple converter to charge multiple low‐ and medium‐power EV batteries of different ratings simultaneously with a low component count.