A voltage and frequency control approach by grid-connected MW class PV systems

This paper presents a voltage and frequency control strategy by grid-connected MW class PV generators. The frequency control is proposed based on a disturbance observer from the view point of the frequency fluctuation problem. A PV generator with a maximum power tracking controller and an energy storage system is connected to a DC bus. An inverter is connected between the DC bus and the grid. An automatic voltage control is provided by this PV inverter along with the frequency control. The proposed system is simulated with the IEEE 14-bus test system by connecting large number of PV generators and is found satisfactory to provide voltage and frequency control.