Observer-based practical control technique for multicell converters

Abstract

The aim of this paper is to propose a generalization of our previous work on practical stabilizing method and switched observer for (low power) single switch DC/DC converters. Generally, the subsystems in PWA models that represent these converters do not share any equilibrium or may not have any one, so that, no strict convergence to any average equilibrium is expected. For this reason, we have opted for practical stabilization that calculates the exact coordinates of the convergence point such that the stabilization error will be known with precision. Using hybrid formalism, a BMI (Bilinear Matrix Inequality) formulation for the design control and the multi-observer one is proposed, both systems i.e. the PWA model and the multi-observer are separately treated as switched systems with a synchronization process. The proposed approach is based on a single Lyapunov-like function and an appropriate continuous state space partition. Power electronic devices are excellent examples of switched and PWA systems that exhibit complicated phenomena and pose still theoretical challenges. Promising simulation results are obtained for all treated examples.