A Low Voltage Ride Through Control Strategy of Optical Storage Microgrid

Abstract

When the distribution network is disturbed or fails, the microgrid connected to it will suddenly leave the distribution network and cause some serious consequences. Aiming at the low voltage ride through (LVRT) capability of the microgrid when the voltage of the distribution network drops, a control strategy of LVRT for the optical storage microgrid based on Quasi-resonant control (QPR) is proposed. During the voltage sag period of the optical storage microgrid, the active power at the DC side is absorbed by the energy-storage device to maintain the voltage stability of the DC bus, and the injection power of the converter is reduced to avoid over-current; The photovoltaic inverter collects the voltage and current at the junction point in the two-phase static coordinate system as the outer loop feedback and the filtered capacitor current as the inner loop feedback to provide the internal equivalent virtual impedance, thus providing the required damping for the filter circuit, and modulates it into a PWM wave to directly control the AC quantity to reduce the impact of the harmonic component on the optical storage microgrid. Finally, the simulation model is built in Matlab/Simulink, The research shows that the control strategy proposed in this paper can effectively maintain the stability of the DC bus voltage and limit the current of the junction point, which confirms the rationality of the LVRT control strategy.