Adaptive Controller with Novel Phase Estimator for LLC Resonant Converter

It is a well-established fact that achieving precise control of an LLC resonant converter operating in sub-resonant mode hinges on the accurate measurement of the phase difference induced by the resonant tank's parameters. Traditionally, this necessitates complex and costly software and hardware setups, presenting a formidable challenge. In this paper, we present a novel and innovative approach through which the phase difference is estimated. This method distinguishes itself by requiring the fewest sensors, resulting in significant cost savings during fabrication. With this method in hand, we propose an adaptive controller designed to maintain a constant output voltage, impervious to disturbances on the input side. To illustrate the performance of the designed observer and controller, the converter equipped with the suggested controller is simulated in MATLAB/Simulink. The results show that stability and disturbance rejection are achieved for the closed-loop system.