Enhanced harmonic compensation control in a bidirectional single-stage resonant PFC circuit for electric vehicle chargers

초록

This paper proposes a bidirectional single-stage DC/AC converter with high-frequency isolation, resonant operation, Power Factor Correction (PFC), and reduced component count. By applying a switch multiplexing concept, the proposed topology utilizes only four active switches on the AC side, compared to the six or eight switches in conventional converters, while replacing the split capacitor with a single capacitor to eliminate voltage imbalance issues. However, conventional sinusoidal PWM introduces low-frequency harmonic components that increase grid current THD. To address this, the harmonic components are analyzed and a compensation strategy is proposed. In addition, a novel small-signal model incorporating beat-frequency dynamics is developed, and a corresponding controller design is presented to avoid instability and oscillations. Analyses of the modulation strategies, operation modes, and ZVS regions are provided, and component design guidelines are given. Finally, a 0.85-kW proof-of-concept prototype is implemented, which is widely adopted in electric vehicle (EV) battery charging applications.

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