A sliding-mode control scheme for llc resonant DC/DC converter with fast transient response

In this paper, a sliding-mode control scheme for LLC resonant dc/dc converter is presented. The proposed controller operates at two fixed switching frequencies with sliding-mode control implementation. The large-signal dynamic model and steady-state characteristics are explored using the extended describing function method. The parameters design and the sliding motions are discussed on the phase plane. The proposed control scheme significantly improves the dynamic response against transient load changes while preserving the closed-loop stability and the attractive features of LLC resonant converter. The simulation and experimental results demonstrate the validity of the sliding-mode control strategy and the fast transient response compared with the conventional PI control.