POWER MANAGEMENT STRAGIES FOR A GRID CONNECTEDPV-FC HYBRID SYSTEM

Abstract

This paper presents a method to operate agrid connected hybrid system. The hybrid system composed of photovoltaic (PV) array and a Proton exchange membrane fuel cell (PEMFC) is considered. The PV array normally uses a maximum power point tracking (MPPT) technique to continuously deliver the highest power to the load when variations in irradiation and temperature occur, which make it become an uncontrollable source. In coordination with PEMFC, the hybrid systemoutputpowerbecomescontrollable.Twooperationmodes,theunit-powercontrol (UPC) mode and the feeder-flow control (FFC) mode,canbe applied to the hybrid system. The coordination of two control modes, the coordination of the PV array and the PEMFC in the hybrid system, and the determination of reference parameters are presented. The proposed operating strategy with aflexibleoperationmodechangealwaysoperatesthePVarrayatmaximumoutput power and the PEMFC in its high efficiency performance band, thus improving the performance of system operation ,enhancing system stability, and decreasing the number of operating mode changes.