Control of a doubly-fed induction generator via a Direct Two-stage Power Converter

In this work, the control of a doubly-fed induction generator using a direct two-stage power converter, connected between the stator and the rotor, is presented. The control of the generator rotor currents is carried out using standard vector control approach with a reference frame aligned with the stator flux. The modulation of the input stage of the power converter is carried out in order to have close-to-unity power factor operation. Experimental results, using a 2.5 kW experimental setup, are presented showing the performance of the rotor current controllers, the bidirectional power flow through the rotor converter for operation below and above synchronous speed, and operation in a variable speed generating system, with the generator driven by a DC drive.