Adaptive output regulation of series resonant DC-DC converters. A combined sliding mode and backstepping control design

This paper proposes a new solution to adaptively regulate the output voltage of series resonant Dc/Dc converters (SRC). The difficulty is twofold: (i) the discontinuous and highly nonlinear nature of these converters which are controlled through a modulating frequency signal; (ii) the uncertain and varying feature of the converter load. Using the first harmonic approximation, the controlled system is first modeled with a fifth-order nonlinear state-space representation. Then, an adaptive sliding mode controller (SMC) is designed and formally shown to meet the control objectives. The involved parameter adaptive laws are obtained using the tuning function backstepping approach.