A Fast and Simple Virtual Oscillator Control for Islanded Applications

This paper presents our proposed virtual oscillator that utilizes the second-order generalized-integrator (SOGI) for the microgrid applications. The second-order generalized-integrator configuration is widely adopted for the synchronization systems in grid-connected inverter applications due to its simplicity and fast dynamic response. The SOGI can generate two output signals that are always 90° difference in phase and are equal in magnitude at a specific operating frequency. The SOGI thus can be considered as an oscillator that has two signals oscillating around the center frequency. In other words, the SOGI can be arranged and configured as a virtual oscillator control. Thus, in this paper, the SOGI is proposed for the microgrid applications to inherit its excellent dynamic performance. The simulation results are presented to verify the theoretical analysis. In addition, the SOGI is implemented in the inverters and it shows great performance for the off-grid inverter applications.