Smoothing Output Power Variations Of Isolated Utility Connected Multiple Pv Systems By Coordinated Control

摘要

A Photovoltaic (PV) system's power output varies with the change of climate. Frequency deviations, tie line voltage swings arc caused by the varying PV power when large PV power from several PV systems is fed in the utility. In this paper. to overcome these problems, a simple coordinated control method for smoothing the variations of combined PV power from multiple PV systems is proposed. Here, output power command is formed in two steps: central and local. Fuzzy control is used to produce the central smoothing output power command considering insolation, variance of insolation and absolute average of frequency deviation. In local step, a simple coordination is kept between the central power command and the local power commands by producing a common tuning factor. Power converters are used to achieve the same output power as local command power employing PI control law for each of the PV generation systems. The proposed method is compared with the method where conventional Maximum Power Point Tracking (MPPT) control is used for each of the PV systems. Simulation results show that the proposed method is effective for smoothing the output power variations and feasible to reduce the frequency deviations of the power utility.