Virtual Impedance Impact on Inverter Control Topologies

The different nature of the energy resources requires high reliable power inverters to supply regulated power to the end customer and to ease its integration within the microgrid. In this paper, modeling, design and control of inverters are presented for two different topologies. The study addresses the feasibility of the single loop and double loop control of inverters. The bode plot technique is used to analyze the system behavior when the inductor and the capacitor currents are used as feedback signals. The different output impedance natures affect the power sharing between inverters and stability. Therefore, a proposed virtual impedance is implemented to enhance the control performance. Simulation results are presented to show the validity of the control strategy.