Flexible Operation Strategy for an Isolated PV-Diesel Microgrid Without Energy Storage

In this paper, a control scheme is proposed for a three-phase isolated photovoltaic (PV)-diesel microgrid without energy-storage element. The scheme aims to: track maximum power from the PVA, regulate the load voltage, compensate the load unbalance viewed by the diesel generator, and to control the diesel-engine speed. The first three tasks are achieved by controlling the pulse width modulation inverter interfacing the PV array to the system. The fourth is realized by a modified fuzzy logic controller of the diesel engine. The obstacles encountered on operating the system under certain probable loading conditions are addressed. Two different operation strategies are proposed to provide high-quality power under all loading scenarios, and to achieve the targets of the control scheme. The system operation is investigated under a variety of conditions to prove the aptness of the proposed techniques.