Discrete state estimation in hybrid photovoltaic systems

In this paper, we will present a new and a simple method based on an Unknown Input observer to estimate the discrete state of the hybrid Photovoltaic systems (PV hybrid systems) where the evolution of the discrete part is governed by a Petri net. The discrete part is presented by the operating mode of the PV hybrid system and the continuous part is related to the control of the power ratio provided by each source according to power sources (climatic conditions) and load variations. The proposed observer is designed in order to estimate both the marking places and the firing vector of transitions and it guarantee exponential convergence of the state estimation error to zero. The sufficient conditions for the existence of the observer are also given. Finally, simulation results demonstrate the convergence of the proposed observer.