Modified Virtual Impedance Control to Improve Real and Reactive Power Output in Islanded Microgrid

In this paper, modified virtual impedance control technique is proposed to bring back the sum of real power and reactive power output of all the distributed generators (DGs) to the nominal value. The value of real and reactive power output falls down in the conventional virtual impedance control technique for reactive power sharing improvement in islanded microgrid. The proposed technique modifies the d-axis component of virtual impedance voltage which in turns brings back the sum of real and reactive power output of distributed generators to nominal value keeping achieved reactive power sharing and output voltage intact. The impact of modified virtual impedance technique on the stability of the system is also investigated using eigenvalue analysis. No communication link or optimization technique is required in this work which reduces the complexity of the system making it more reliable and easier to design. The proposed technique works satisfactory for local load as well as the loads which are connected distantly from the distributed generators. The feasibility of the proposed technique is validated in time domain simulation in MATLAB/Simulink. The MATLAB R2020b version 9.9 is used in this research work.