Fourth order L3C resonant converter for wide output voltage regulation

In order to fully cover the V-I plane of deep-cycle batteries, battery chargers should work under different loading conditions and output voltage, and should respond to different States of Charge (SoC). In this paper, a fourth order L3C resonant converter is introduced and employed as a battery charger. The analytical equation of the L3C voltage gain shows the possibility of regulating wide output voltage to an unprecedented degree within a narrow frequency range to cover the entire V-I charging plane of modern batteries. The topology integrates all of the parasitics elements into the resonant circuit, realizes ZVS for the inverter MOSFETs, and provides inherent over-current protection capacity. These advantages provided by the proposed L3C resonant converter make this topology an excellent candidate for use as a charger in Electric Vehicles. The experimental results extracted from a 220V DC; 550W resonant converter platform with a peak efficiency of 96:5% exhibit the excellent performance of the proposed converter for battery charger applications.