Peak Current-Mode Control for <i>LLC</i> Resonant Converter

This paper proposes a direct current control scheme for LLC. The novel approach, achieved by precisely regulating the peak current across the resonant tank to enable a high bandwidth and rapid dynamic response, has proven the stability enhancement and dynamics response improvement through output impedance analysis and load-step simulation. The regulator directly controls the switches involving a reference signal, the sampled peak value of the resonant tank current, and a slope compensation signal based on coordination of DSP software algorithms and its integrated analog peripherals. This enables fully digital control, enhancing flexibility and reducing costs. The effectiveness of this approach is validated through a 24V/1kW half-bridge LLC converter prototype.