Resonant Switched Capacitor Converter with Conduction Losses Reduction by Generating Trapezoidal wave current for Electric Vehicles

EV battery voltages are increasing from the conventional 400 V to 800 V. To fully utilize existing 400 V chargers for such high-voltage batteries, an on-board boost converter with a step-up conversion ratio of 2.0 is required. Resonant switched capacitor converters (RSCCs) are known as the best topology to reduce circuit volume. However, a rms current of the resonant sinusoidal wave is larger than their input current, leading to increased conduction losses. This paper proposes a PWM modulated RSCC to reduce conduction losses by generating the trapezoidal wave current. In addition, the trapezoidal wave current can further reduce current stresses due to reducing current amplitude. A prototype verification test demonstrated the reduction of conduction losses by approximately 12% compared to the conventional method.