A simple method of controlling real and reactive power for a grid-tied inverter

摘要

The integration of renewable energy sources into an existing grid requires grid-tied inverters. The reliable and accurate dispatch of real and reactive power to the grid is achieved by controlling the inverters. Recent trend is to operate such grid-tied inverters as virtual synchronous generators. This requires time-intensive solution of the complex machine equations to control the inverter outputs. This paper demonstrates the development of a simple method for real and reactive power control for the inverters. The method is based on simple circuit theory. For a set values of real and reactive power the magnitude and angle of the inverter output voltage is determined. The PWM technique can be applied to the inverters in order to maintain the calculated operating point. The results obtained from the proposed method have been compared with those obtained from a detailed method. The agreement proves the accuracy of the new technique.