CONTROLLER VALIDATION AND VERIFICATION FOR A DOUBLY-FED VARIABLE SPEED WIND GENERATOR SYSTEM

The paper deals with a variable speed wind turbine fitted with a DFIG (Doubly-Fed Induction Generator) vector control system. A new rotor active power feedback, under the cascade regulation superordinated both to the DFIG rotor current internal feedback and the DFIG stator power external feedback has been introduced. The DFIG vector control system fitted with an external rotor active power feedback enables the wind turbine rotation speed to be controlled by means of the rotor active power reference. By introducing a rotor active power feedback into the DFIG vector control system, a power flow control in the generator rotor circuit is rendered possible in both stationary and dynamic wind turbine operation modes. The DFIG vector control structure has proved to be particularly suited to wind turbines with pronounced wind speed time changes. The paper also discusses the wind turbine dynamic characteristics with and without a feedback rotor active power within the DFIG vector control system at varying and sudden variations in rotation speed.