LLC Type Resonant Converter Adopting Peak Current Shaving with Third Harmonics Injection for Wide Output Voltage Range Application

This paper details a novel control method designed to diminish peak and rms resonant currents in the resonant tank of a proposed half-bridge two-LLC resonant converter, operating across an extensive voltage range. This converter incorporates different resonant tanks, one operating at the fundamental frequency and the other at three times the fundamental frequency. To accomplish the objective, the study adopts phase shift control to effectively regulate the switches in the two half bridges to achieve in-phase alignment between two currents, optimizing the superimposed current shape to achieve lower peak and rms values, while concurrently minimizing circulating energy and output voltage ripple. The report exemplifies the methodology through the meticulous design of a universal 380V input converter, featuring a wide output range of 250V to 420V.