A High Frequency Control Strategy for An LLC Circuit

With the large-scale construction of power system network, the harmonic frequency of power facilities and equipment increases gradually, and the output ripple increases correspondingly. A ripple suppression control method for high frequency LLC resonant circuit is proposed in this paper. The topology modeling of the circuit adopts the extended description function method, and the output current and voltage are taken as output variables. Based on the stability criterion of the small gain theorem, the stability of the frequency control compensator is designed, so that the circuit can be realized in the wide voltage or constant current output regulation range by frequency conversion control, to ensure that the switching device can be realized in the working frequency range, and effectively suppress the output ripple. Finally, a high frequency LLC circuit prototype is constructed to verify the proposed control strategy.