Two-Step Robust Design of LLC Converter With Corner Judgment and Greedy Algorithm

Negative effects caused by parameter fluctuation (PF) of resonant elements have not been thoroughly considered in the current design methodologies of
LLC
converters. In this letter, typical negative PF effects are revealed as restriction violation and optimization degradation. Then, a novel two-step robust design methodology is proposed for
LLC
converters. The first step is to effectively establish more reliable solving domain considering PF effects on all the restrictions by the proposed corner judgment method. In the second step, the lowest fluctuation efficiency as the novel concept is proposed and taken as the global optimization goal of efficiency due to optimization degradation, with a greedy algorithm proposed for simplicity and effectiveness. Simulation and experimental results have proved the validity and superiority of the proposed design methodology.