Gain optimization control method for CLLLC resonant converters under phase shift mode

Abstract:
Bi-directional capacitor-inductor-inductor-inductor-capacitor (CLLLC) resonant converter is widely used in applications such as energy storage systems and portable power stations to efficiently charge/discharge batteries. However, an efficient CLLLC resonant converter has a challenge of covering a wide battery voltage range with various load conditions. Especially at light load, output voltage tends to rise due to parasitic capacitance and could eventually go out of regulation. In this paper, phase shift control is introduced to main output voltage regulation at light load. In addition, a novel synchronous rectifier control method is proposed in this abstract to eliminate the nonlinearity effect caused by parasitic capacitance.