A novel voltage control strategy based on the virtual impedance for seamless transfer of the dual-mode inverter

In distributed generation(DG)unions, the requirements of inverter could be operated in island mode as a voltage source, which could also be operated in grid-tied mode as a current source. When the inverter transfer between the two modes, which may arouse spike of the voltage and current. This paper analyzed the features of inverter in voltage control mode and current control mode, respectively, and then presented a novel voltage control strategy based on the virtual impedance related to the filter inductor current to complete the seamless transfer between the two modes. The algorithm was discussed in detail in this paper. Computer simulation and experiments proved the feasibility of this control scheme.