Power Balancing Controller Design of Multiple Resonant Converters by PFM and PWM Methods

초록

LLC converters are widely used as DC/DC converters in electric vehicles (EVs) chargers. However, a single LLC converter has limited output power capacity, necessitating a multi-converter configuration. Traditional control methods use pulse frequency modulation (PFM) to regulate the output voltage and manage power balance, but this approach can lead to performance degradation under dynamic conditions. In this paper, a hybrid control method is proposed, where PFM is used to regulate the system's output voltage, while power balance is managed using pulse width modulation (PWM). The proposed method is applied to a system consisting of three LLC converters operating in parallel. Simulations validate that the total output power of 7.2 kW is achieved while ensuring optimized power distribution.

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