Rotor current PI controllers in the method of output voltage control of variable speed standalone DFIG

Doubly fed induction generator DFIG operating in standalone mode is described. Analysis of single phase model allow for the selection of the filtering capacitance connected to the stator. The standalone DFIG is compared to the classical synchronous generator with DC excitation current. Method of output voltage control using PI controllers of the rotor current is shown. Decoupling between the amplitude and frequency of the stator voltage allow for the simple prototyping and step response based tuning of the PI controllers. Rotor current PI controllers are used in the rotating frame connected with a rotor current vector. They are designed using simplified model of the rotor excited slip ring induction machine. Results of simulation with 250 kW slip ring induction generator are shown. Laboratory results of 2.2 kW DFIG supplying the different type of load is presented.