Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title PWM Synchronization Method for Parallel-Connected LLC Resonant Converters for Reducing Circulating Output Current Ripple
Authors Chae-Lyn Kim ; Byoung-Kuk Lee ; Yong-Su Noh ; Hyoung-Kyu Yang ; Joon-Sung Park ; Jin-Hong Kim ; Jun-Hyuk Choi ; Dongmyoung Joo
Page pp.315-324
ISSN 1229-2214
Keywords Paralleling of LLC resonant converter; PWM syncronization method; Reduce output current ripple
Abstract As demand for electric vehicles (EVs) increases, high-power EV batteries and chargers should be improved to overcome the limitations of mileage and the battery charging speed. State-of-the-art battery chargers consist of several unit converter modules with a parallel output connection to increase the maximum-rated output power. Frequency-controlled load resonant converters play a major role in the design of modular battery charger systems. However, each module has different resonant and operating frequencies owing to the manufacturing tolerance of the resonant elements, which can cause a severe output current ripple that can reduce the lifespan of the battery as well as the output capacitor of the charger. This study proposes a method for mitigating the output current ripple caused by the pulse width modulation synchronization method without any additional hardware, so it can be easily implemented in any conventional charger. Furthermore, this study verifies the effectiveness of the proposed method through a simulation.