Modelling and control design of a multi-source renewable energy system with coupled DC/DC converters power compensation

This paper investigates the electrical energy transfers control in a multi-source renewable energy system. The considered system is composed of two sources (photovoltaic and lead-acid battery bank), a specific zero voltage switch full-bridge isolated buck DC/DC power converter and the load. The main contribution of this paper is to propose a modelling approach that details the coupling and uncoupling of DC/DC power converter on a DC bus of multisource renewable energy systems. The proposed model is suitable for control and performance evaluation. This modelisation, results in a system with two cascade loops, the inner loop which allows the control of the current and the outer loop which controls the output voltage using a PI and a PID two controllers respectively. We show by means of numerical simulation tests that the proposed control gives good results in terms of robustness and stability despite the fluctuations of renewable sources and the load variations.