Low voltage ride-Through strategy based on virtual synchronous generator control

摘要

Inverters controlled in virtual synchronous generator(VSG) method is able to operate in both grid-connected mode and islanding mode. Due to this characteristic, this paper put forwards a low voltage ride-through(LVRT) strategy which is based on VSG control. If the grid voltage sags, VSG can limit the output current amplitude and meanwhile inject reactive power to the grid. Once the voltage drop time exceeds the maximum ride-through time, VSG would smoothly switch to islanding mode and continues to carry loads independently. The proposed strategy achieves a control algorithm unity between normal operating and grid voltage sag status in grid-connected mode. Simulations can support the validity of the strategy.