An APWM controlled LLC resonant converter for a wide input range and different load conditions

摘要

This paper introduces a LLC resonant converter regulated by asymmetrical pulse width modulation (APWM). This topology has the capability to achieve soft-switching for both switches in a wide range of input DC voltage as well as load current. By properly choosing the component values of the resonant tank, the converter can provide a regulated voltage for all line and load conditions as well as maintaining a relatively high overall efficiency. The steady state analysis of the converter and the design procedure for components selection are presented in the paper. Furthermore, the load-dependency characteristic is investigated. A design example is included to illustrate the proposed procedure. Simulation results show that the converter can provide a regulated 5V output voltage with the input DC voltage ranging from 35V to 75V.