Stator harmonic current compensation of a DFIG connected to a grid with voltage distortion

The number of worldwide installed wind power plants has been growing rapidly. With the development of power electronics technology, the new wind power systems are able to optimize the extraction of the wind energy. Among the systems configurations, the doubly-fed induction generator (DFIG) is the most used, since it can make the system operate with variable speed, while using a low-cost power converter. However, there are some drawbacks in this configuration. One of the most important is the fact that the machine stator is directly connected to the grid and then, it is influenced by grid parameters variations. In some cases, a control method that aims at blocking the harmonic currents that flow to the machine stator might be essential to its proper functioning. This paper analyzes a stator harmonic current compensation, based on resonant controllers technology. The analysis is carried out in a hardware-in-the-loop configuration using a Texas Instruments microcontroller, and the system plant is simulated with the software PSCAD/EMTDC.