Single-Input Multi-Isolated-Output SEPIC-Ćuk Converter for E-Bike Charging: Modeling, Design, and Prototype Implementation

Abstract

As the global automotive industry shifts towards greater electric vehicle (EV) adoption, developing countries have also increased their funding for EV infrastructure development. As more charging stations are built, it also becomes critical to ensure that the waiting time before charging is reduced. Reducing waiting times will be crucial in promoting EV adoption. The majority of individuals prefer using electric two-wheelers, such as electric bikes (e-bikes). The e-bikes use low-voltage batteries, which need low power. Therefore, it is crucial to implement chargers that are suited to charge low-voltage, low-power EVs. This study proposes a single-input multi-output (SIMO) modified SEPIC-Ćuk Combined Isolated DC-DC Converter for charging low- and medium-voltage batteries with varying power levels. The modes of operation are described in detail with the pertinent dynamic equations. The non-ideal modeling of the proposed converter parts is detailed. Calculations of the currents and voltages of the components are provided after presenting the converter design for the considered specifications. A detailed design of the high-frequency transformer is provided with the corresponding design equations. The criteria for the selection of components are described, along with the importance of testing the transformer frequency range. Simulation results are provided to validate the calculations, and the converter hardware prototype is implemented to validate the operation and novelty. The high frequency of MOSFET switching ensures a reduced size of inductors and capacitors, leading to a reduced converter size. The proposed converter is a novel isolated DC-DC converter that can be used to charge three EV batteries of different voltage levels simultaneously for low- and medium-power EV applications.