Field Oriented Current Vector Control of Double-Fed Induction Wind Generator

As double-fed induction wind generator the three-phase slip-ring induction machine is applied mainly. Tentatively brushless double-fed three-phase machines are also used. This paper describes the slip-ring version only. In the advanced version the rotor is supplied by frequency converter constructed from two identical voltage-source converters. Both should be current vector controlled. The line-side converter can provide approximately sinusoidal line current with unity power factor. The machine-side converter can be controlled to result in stator current with unity power factor, so the resultant line current is approximately sinusoidal with unity power factor. Therefore the advanced double-fed induction machine drives do not need additional reactive power compensation, moreover the resultant line current can be even capacitive. This paper deals with the stator flux field oriented rotor current vector control of the machine side converter. The possible implementations are overviewed and compared. One of them, the space vector PWM current vector control is investigated by simulation