A novel stator voltage distortion and unbalance compensation of a DFIG with series grid side converter using adaptive resonant controllers

Among the variable-speed wind power systems the DFIG configuration is one of the most interesting ones since it can achieve optimal power extraction of the wind energy using a low-cost, low-rated-power converter. However, there are some drawbacks in this wind system configuration considering that its stator is directly connected to the grid. Distorted and unbalanced grid voltages can lead to many power quality problems that must be solved in order to obtain a proper operation and to meet grid codes. In this paper, the DFIG operates with a series grid-side converter and a novel control scheme using adaptive resonant controllers is proposed in order to achieve voltage distortion and unbalance compensation, maintaining the stator voltage balanced and sinusoidal and thus, enhancing the generated power quality. The analysis is carried out in a hardware-in-the-loop configuration using a microcontroller, and the system plant is simulated on the software PSCAD/EMTDC.