The Research On Power Quality Of VSCF Wind Power Generating System

Wind energy is a conversional form of solar energy, which can't be used up, and it doesn't pollute circumstance. So wind power generating technology is paid more attention by many countries in the world. Our country also begins to exploit the resources of wind energy.VSCF wind power generating technology is a new style technology which has developed in recent years. Only if the power quality corresponds to the national standard, the technology is practical. The total harmonic distortion must not be greater than 5% in the national standard. Based on this purpose, harmonics produced by VSCF wind power system is analyzed in this paper, and effective control strategy is researched to decrease the harmonics.This paper firstly analyzes the cause of harmonics produced by VSCF wind power system. VSCF wind power generator is an AC excited machines fed by the SPWM inverter. The selection of inverters and the control of it play a decisive role in the suppression of harmonics. Then, the theoretical analysis and simulation on harmonics of SPWM inverter is deeply carried out , the trends toward which harmonics vary with inverter parameters have been researched and the rule of harmonic spectrum distribution is given. Next, control strategy is applied to eliminate the harmonics, a lot of experiments have been done to verify it At last, in order to further eliminate harmonics and restrain EMI, the inverter output EMC filter is designed.The theoretics and experimental results show that the control strategy is successful. However, the cause of harmonics produced by system is rather complicated, so solving it completely is very difficult. Some of key technologies should be perfected in the future.