Improved Soft Switching Technique for Dual Active Bridge Converter Applied to Electric Vehicle Fast Charging System

Abstract

The Electric Vehicle Fast Charging System (EVFCS) consists of an AC-DC converter and multiple DC-DC converters to charge the Electric Vehicle (EV) battery. The Dual Active Bridge (DAB) Converter is the most promising topology of DC-DC converter owing to its advantages such as galvanic isolation, bidirectional capability, high voltage gain, inherent soft switching and high efficiency. The DAB converter controls are designed to achieve Constant Current (CC) Charging. It is controlled by employing Phase Shift Modulation (PSM) techniques to achieve the desired power transfer. The Voltage Source Converter (VSC), is the front end AC-DC converter which is designed to maintain a stiff DC bus voltage. In this work, the DAB converter is controlled by employing improved Triple Phase Shift (TPS) scheme to improve the soft switching region for the converter. The proposed control scheme is verified with the simulations performed in MATLAB/Simulink and the experimental validations are done using Real Time Digital Simulator OP4610.