Modified Quasi-Z-Source Resonant Converter–Based Concurrent CC-CV Charging in a Dual-Port Charger for EV Applications

Conventional multiport resonant converters are the most sought-after solution to reduce the installation costs of electric vehicle battery charging applications. Despite its attractive features, LLC resonant converters face limited extension of the duty cycle, operate in multistage power conversion, and mainly rely on pulse frequency Modulation (PFM). To resolve these problems, a single-stage power conversion topology, known as a quasi-z-source resonant converter, has been recently introduced at fixed-frequency operation to concurrently charge two batteries. However, the work has not addressed the constant current and constant voltage (CC-CV) mode operation concurrently. Moreover, the use of traditional PWM has reduced the overall efficiency of charging. To address these issues, this article proposes a modified dual tank resonant circuit integrating a quasi-z source inverter (MQZSRC) to charge the two batteries in CC-CV modes concurrently. The improved MQZSRC employs phase-shift PWM achieved by carrier shifting techniques with the aid of theWAVECT WCU 300 controller at a fixed frequency with and without shoot-through duty cycles. The test results related to enhancing efficiency and voltages are documented and compiled. The MQZSRC achieved validation in a laboratory prototype, where each circuit is powered with 200 W, and achieved overall 90% efficiency.