LCLC resonant converter with PWM control

This paper describes the theoretical and practical aspects of an LCLC resonant topology, operating at constant frequency (PWM control). This topology combines the behavior of LLC and LCC converters, introducing the advantage of reducing the value of the series resonant inductor to get high power factor for the resonant tank. The inclusion of a new resonant element, the parallel capacitor, allows reducing the resonant current through the magnetizing inductance, thus reducing the power losses in the transformer. Although part of the transformer losses are transferred to the parallel resonant capacitor, they can be minimized with a correct selection of this resonant component.