Keywords: explicit solution, MLD modelling, model predictive control, non-inverting Buck-Boost converter, PWA model, synchronous DC-DC converter, nonlinear dynamics, controller design, simulation
Hybrid modelling and control of a synchronous DC-DC converter
In this paper, the problem of hybrid modelling and control of a fixed frequency DC-DC converter, namely the Non-inverting Buck-Boost converter is addressed. The v-resolution method is used to capture the hybrid nature of the system. Two mixed logical dynamical (MLD) models are obtained for the converter using hybrid systems description language (HYSDEL). In the process of using v-resolution concept, the problem of non-linear terms in state update equations is solved using piecewise affine approximation. Three PWA models are obtained using least squares fitting over non-linear dynamics of the system. A suitable model in terms of accuracy and complexity is chosen for controller design. Model predictive control is used as the control strategy and explicit solution to the control problem is obtained. Finally, the simulation results are presented. The accuracy and complexity of the models are compared and the performance of the controller is evaluated over three different scenarios which are common in practice.