Application of fuzzy control to residential cogeneration with renewable energy sources

A fuzzy PI controller and a conventional PI controller were adopted to develop control for a residential cogeneration system made by a biomass-fired and solar-powered fluidized bed prototype. Its mathematical model is characterized by nonlinearities and, more important, by uncertainty and variability in parameters. The paper describes in detail the PI fuzzy controller, the development of which was based on the knowledge of the continuity diagrams of the process model. Then, the paper reports a comparison in simulation between the PI fuzzy controller and the conventional PI one. The PI fuzzy controller exhibits a superior performance, as far as both robustness and rate of response. As a result, the adoption of a PI fuzzy controller turns out the best choice for this residential cogeneration system and a favorable option for nonlinear processes with uncertain or time-varying parameters.