METHOD AND SYSTEM FOR CONTROLLING CONTINOUS HIGH VOLTAGE RIDE-THROUGH AND LOW VOLTAGE RIDE-THROUGH OF PERMANENT MAGNET DIRECT-DRIVEN WINDTURBINE

The present application provides a method and a system for controlling continuous high voltage ride-through and low voltage ride-through of a permanent magnet direct-driven wind turbine. The method includes: determining a transient time period during which the wind turbine is transitioned from a high voltage ride-through state to a low voltage ride-through state; controlling the wind turbine to provide, during the transient time period, a gradually increasing active current to the point of common coupling; and controlling the wind turbine to provide, during the transient time period, a reactive current to the point of common coupling according to an operation state of the wind turbine before the high voltage ride-through state. According to the embodiments of the present application, voltage of a power grid can be effectively supported.