A review of direct power control technologies of DFIG with constant switching frequency

The technologies of direct power control (DPC) of DFIG with constant switching frequency have become a focal point due to their easy design of the power converter and the ac harmonic filter, also due to the reduction of the harmonic of the stator current and less power lose. This paper provides a comprehensive review of this technology. It is shown that the direct power control with constant switching frequency is mainly achieved by using the PWM, SVM, DSVM-DPC, and P-DPC respectively. The principle of the schematic and the advantages or disadvantages of each approach are proposed. The difficulties in the application of the technology are also analyzed.