An Adaptive Virtual Resistance Control Strategy for Grid-Connected Inverter with Virtual Oscillator Control

Virtual oscillator control (VOC) strategy is a new distributed control method which has great potential for grid-connected inverter. However, in stiff grid with large short circuit ratio (SCR), VOC tends to lose synchronicity with the grid, since the lack of system inertia. In this paper, a complete small-signal model of grid-connected inverter with voltage-current inner loop VOC is presented. Then, an adaptive virtual resistance control strategy is proposed based on system stability assessment with eigenvalue. The proposed control strategy not only improves the system stability, but also compensates for the voltage drop due to the line impedance and the added virtual resistance. The proposed strategy's effectiveness has been verified through simulations in MATLAB/Simulink and experiments.