Gain-scheduled control using voltage controlled oscillator with variable gain for a LLC resonant converter

This paper proposes gain-scheduled control using voltage controlled oscillator with variable gain for a LLC resonant converter to improve the dynamic performance. Considering the effect of switching frequency to the gain function of a LLC resonant converter, control loop gain is scheduled by voltage controlled oscillator with a frequency-dependent gain. The effective gain function for VCO is proposed, and a design example is presented. Enhancement in dynamic performance with the proposed method is verified by the comparison of experimental results with the conventional control method.