Variable Structure Adaptive Control of LLC Resonant Converter

Abstract

This paper presents the Model reference adaptive variable structure controller for second order system of LLC converter to control the output voltage and rectifier current. The small signal model of the converter is developed by using extended describing function and Jacobean Linearization methods. Seven state small signal modeling of the converter is reduced to two measurable states using the relationship between the state variables. The Lyapunov adaptive method is used to estimate the sliding mode controller parameters to solve the disturbance caused by parameter variation in the converter. The converter is designed for 4kV output voltage and 0.55A output current. The simulation result indicates that the adaptive sliding mode controller has settling time (ts) 2.5msec and rise time (tr) 4.5 μsec respectively, while the steady state error (ess) is 0.2%.