A PV-Battery System Operating in Islanded and Grid Connected Modes with Shunt Active Filter Capability

This paper presents a battery integrated photovoltaic (PV) system, which provides reliable power to local loads, by operating in either islanded or grid connected modes, depending on the grid conditions. When the grid parameters violate the defined limits, the system seamlessly transfers to an islanded operation. In case the PV power surpasses the load demand, the battery absorbs the remaining power, thereby ensuring optimal utilization of the PV power. On recovery of normal grid, the system is capable of seamlessly resynchronizing to the grid. In grid connected operation, the grid provides the power if the PV power is deficient, and absorbs power, if the PV power is in excess. The system further incorporates the benefits of an active shunt filter, thereby enhancing the power quality. This system is single stage, and the PV power is directly given to the voltage source converter (VSC). The battery is connected by a bidirectional DC-DC converter (BDDC), which maintains the voltage of the DC link at the reference voltage provided by an incremental conductance technique, to derive optimum PV power.