Demagnetization Analysis of a V-shape PM Salient Pole Wind Generator under Sudden Short-Circuits after Rated Load Condition

To improve the output parameters of PM salient pole wind generator, the V-shape permanent magnet salient pole wind generator (VPMSPWG) was previously proposed. Its special structure can not only protect PMs well, but also increase the generator’s output power. In this paper, its PM demagnetization performance under three-phase symmetrical short-circuit is investigated. The maximum sudden short-circuit current is obtained based on a calculation formula which is deduced in this paper. In order to estimate the most serious demagnetization condition, the maximum sudden short-circuit is used as the demagnetization current and the PM demagnetization with different structure parameters are studied by finite element method (FEM). The investigation results show that the operating temperature determines whether there is irreversible demagnetization during sudden short circuit and the rotor structure have evident effect on demagnetization performance. After comparison and analysis, the appropriate working temperature is suggested. The PM angles and non-magnetic material shapes with minimum demagnetization are selected out to enhance the anti-demagnetization ability of VPMSPWG.