Fuzzy Logic Based Controller with Dedicated Safety Function for Hybrid Renewable Energy System

Abstract

For the dual reasons of energy security and environmental and climate preservation, there has been a global campaign for drastic reduction in the use of fossil fuels and a consequential aggressive pursuit for the development of clean energy systems. Hybrid renewable energy systems, ahead of single source renewable energy systems, promise to be an effective alternative to the use of fossil fuels. However, if hybrid renewable energy systems must effectively and reliably serve as an alternative to fossil fuel use, then improvements in the control and management of energy flow among the renewable energy supplies, energy storage components, and the load is of very vital significance. More intelligent and optimized, and easy-to-develop control techniques need to be introduced to replace already existing conventional techniques. And very importantly, extra measures have to be taken to ensure longer battery life and the overall safety of the system. This work is a design of a fuzzy logic-based control system for managing energy flow in a hybrid renewable energy system. A dedicated output was incorporated in the fuzzy controller for controlling the load connection status. The results showed that the fuzzy logic controller accurately emulated expert decisions in monitoring the battery state-of-charge and renewable energy supply capacities, and effectively determining and controlling the battery charging and discharging functions. The employment of fuzzy logic control in the system eliminated the need for complex and tedious mathematical modelling as required in conventional control methods. Thus the system was easier to develop.