Harmonics of Double-fed Wind Power System with Grid-Tied Dual-PWM Converter

Abstract

To fill the gaps of the double-fed wind power system, this paper conducts a study for the scarcity and integration of social resources. The LF harmonics on the DC and grid sides are surveyed based on the double Fourier transform algorithm, in conjunction with the power balance theory. A study model has also been built herein. The findings show that the calculated values of the HF harmonic components in the DFIG rotor current almost coincide with the simulation results, regardless of whether the wind velocity is 7 m/s or 19 m/s. When the three-phase voltage of the grid is unbalanced, the stator current contains the grid side basebands with LF harmonics of odd times, among which, the fundamental frequency of triple grid side baseband is the most distinct. It is thus clear that the simulation can capture relevant voltage and current data for the wind power system running in the balance and unbalanced states of grid voltages. it is therefore proved that the theoretical analysis is accurate and reliable.