Power conversion in a grid-connected residential PV system with energy storage using fuzzy-logic controls

Abstract

Increasing implementations of renewable energy resources to migrate from fossil fuel based electric power to clean energies have been creating new technical challenges due to their integration into an existing electrical grid. In this research, a power electronic converter based on fuzzy-logic controller is developed to govern the transfer and control of power in a grid-connected residential photovoltaic (PV) system with battery storage. A bidirectional dc-dc converter is designed for power transfer between the loads and the battery. A bidirectional ac-dc converter is used as the interface between the PV array and the electricity grid. The fuzzy-logic controller is designed to meet the user power requirement—with the PV array and the battery sized to meet the critical load requirement on site. The results indicate that the fuzzy-logic-based power conversion helped the system to adjust to off-grid, low-battery, full-battery, and on-grid power conditions. The main merit of the design is simplicity in being able to manage the limited supplies from the grid and the renewable PV installation using carefully sized storage that serves critical loads within specific days of power autonomy.