Natural Trajectories and Digital Implementation of Load Dynamic and Soft Start-Up for LLC Converters

LLC resonant converter, with high efficiency and good dynamic response, finds potential applications in secondary DC/DC converter for satellites. This paper proposes a digital implementation methods to achieve better transient performance based on natural trajectories for LLC converters during load change. In order to increase the reliability for satellites, this paper presents an optimal soft start-up process to minimize voltage and current stress. Validity of the proposed two control methods are verified by simulation and test results.