VSG Low Voltage Ride Through Control Strategy Based on Internal Potential Compensation

Virtual synchronous generators(VSG) are integrated into the power grid as the control strategy of the inverter, which has good inertia and damping characteristics. However, when the grid voltage drops, the traditional VSG control will have problems such as power angle instability and fault current overcurrent during the voltage drop due to the lack of low voltage ride through capability, which seriously threatens the safe operation of the system. A method different from the existing control strategy is proposed. The proposed control strategy can maintain the power angle stability and limit the fault current during the grid voltage drop, and provide some reactive power support for the grid under the premise of safe operation. Firstly, the fault characteristics of VSG are analyzed during the grid voltage drop. Secondly, a VSG low voltage ride through control strategy based on internal potential compensation is proposed. By analyzing the phasor diagram of the system during voltage drop, the calculation method of internal potential amplitude and phase compensation is given. Finally, the effectiveness and correctness of the proposed control strategy are verified by simulation.