Experimental Verification of Energy Conversion Efficiency of Doubly Fed Wind Turbine

As a large inertia rotating mechanism, large-scale wind turbine, converts wind energy into electric energy. It is difficult to characterize the operating conditions in factory test. In order to accurately grasp the energy conversion capacity of large horizontal axis doubly fed wind turbine, mechanical loss and electrical loss in the drive-train of doubly fed wind turbine have been analyzed. The energy conversion capacity of wind turbine is obtained by type test, and the characteristics of energy conversion efficiency of doubly fed wind turbine are proved. In the constant speed range near the cut in wind speed, the energy conversion efficiency of the doubly fed wind turbine increases significantly from 50% to 80% with the increase of power. After entering the maximum power point tracking range, the energy conversion efficiency slows down with the increase of power, and the efficiency can reach 92%∼93% at half rated power. After entering the rated speed range of the generator, the overall efficiency is asymptotically and stably maintained at more than 93%, and the overall efficiency can reach about 93.4% at rated power. This study has mastered the characteristics of segmented efficiency in the operation range of doubly fed wind turbine, and will carry out targeted customization and test verification research on energy efficiency improvement strategy in each operating range.