Improvement of the Coupling of Renewable Sources through Z-Source Converters Based on the Study of Their Dynamic Model

Abstract

The classical coupling of renewable energy sources greatly limits the coupling power and the output voltage of the coupled sources. Moreover, it does not eliminate the randomness of the sources. In this work a renewable sources coupling with high randomness is obtained by series connection of the output terminals of Z-source converters. To achieve the coupling, the stationary and dynamic models of a Z-source-based converter have been studied. With the results of the stationary model, the converter behavior has been evaluated as a function of its parameters and a method for calculating the Z-network parameters has been implemented. Moreover, with the dynamic model a controller has been designed for all the converters. The main contributions of this work are the coupling of the sources, the stationary and dynamic models obtained and their analysis. The coupling achieves a stable supply avoiding the sources' randomness reaching the load. A system composed of a wind turbine, a set of photovoltaic panels and two groups of batteries has been modeled. To study the system behavior and the supply quality, several aggressive tests have been forced and experimental evidence has also been provided