Analog Compensator Design for Half Bridge LLC Resonant Converter

Due to high efficiency and high power density LLC resonant converters are getting very popular and are gaining more and more interest in DC to DC power conversion applications. Usually, these converters are used in low power applications, however they are very popular in high power and renewable energy applications as well as in many more applications which are affected by line or load variation. In this paper, in order to keep the output voltage regulated step by step methodology to design analog compensator is presented. This analog compensator controls the frequency of the pulses generated by voltage control oscillator (VCO) for driving the MOSFETs. For obtaining the open loop transfer function of the plant, extended describing function (EDF) method is used. The proposed compensator design is developed in MATLAB/Simulink environment and simulation results showed that the proposed compensator can adjust the output voltage level effectively for both the line and load variations.