A new control method for improving transient response of parallel VSIs in islanded microgrids

Abstract

Recently voltage source inverters have played an important role in stability of Microgrids (MGs). These inverters are controlled by droop control method. This method has several advantages such as using of local signals and satisfying steady state behavior of VSIs. But in transient, inverters have unbalanced power sharing and consequently circulating current flows between them. This current without feeding load flows and causes losses. In this paper for eliminating these problems, a new method based on conventional droop method is presented. This new method uses absolute value of current signal only and replacing LPF by a DC Mean Block. To compare two methods, a system with two parallel inverters is simulated in MATLAB. Comparison between Results of two methods shows effectiveness of proposed method in improvement of VSIs' behavior in transient response.