Power Fluctuation Suppression Under Distorted Grid Voltage in Wind Power System Using Wound Rotor Induction Generator

This paper proposes a suppression method of power fluctuation of wind power systems using wound rotor induction generator. Especially, fluctuation at 6 times the grid frequency caused by distorted grid voltages is our main target. Wind power systems are commonly installed at the end of the power system, where grid voltages distort due to asymmetrical loads or difference in transmission line impedances. In this case, component at 6 times the grid frequency is generated in the generated power. Though methods for suppressing power fluctuation for grid voltage distortion have been investigated by authors, these methods were not effective enough when the phases of the 5<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> and 7th harmonics in the grid voltage were shifted from the phase of the fundamental component. In this paper, first, components at 6 times the grid frequency of generated power of a wind power system using wound rotor induction generator are analyzed. Next, the harmonic current references which minimize the components are derived. Furthermore, simulation results demonstrate that harmonic current control using the derived references can minimize the components at 6 times the grid frequency of the power even when the phases of the 5<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> and the 7th harmonics are shifted from the fundamental component.