VOLTAGE AND FREQUENCY CONTROL FOR INVERTERS IN MICROGRID

Abstract

The inverters in Microgrid are connected in parallel to improve efficiency, increase transmission capacity, and easy to repair and maintain. When the Microgrid is operating in standalone mode, the inverters must be controlled to share their power according to the rated ratio, this is to stabilize the frequency and voltage in the Microgrid. The droop control method for power control for parallel-connected inverters is one of the most popular power-sharing methods today, some studies have presented traditional and improved droop control methods. However, the purpose of the studies is power-sharing for the inverters that no purpose of reducing the voltage and frequency deviation to improve power quality. This paper is shown the adjusting of the voltage and frequency method based on fuzzy logic with an aim is minimize the voltage and frequency deviation for improving power quality in Microgrid. This controller consists of a Droop combined with fuzzy logic to control changes in the slope of the power curve when the load changes, thereby the voltage and frequency deviation could be adjusted. This control method is called the Droop-fuzzy logic control method. Experimental results confirm the validity of the proposed control. Simulation and experimental results will prove the effectiveness of the proposed method.