Research On Squirrel Cage Asynchronous Wind Power Generator With High Power Density

In the rapidly developing field of wind power, the main generator typesare double-fed wind turbine and permanent magnet direct drive wind turbinesand squirrel cage asynchronous wind turbine at present. Among them, thesquirrel cage full power wind power generation system has gained more andmore application because its simple structure, low cost, easy maintenance andthe large range of speed change. The high power density of wind generator isthe inevitable requirements of the large capacity, miniaturizationdevelopment in wind power. High power density is carried out by improvingthe magnetic load and thermal load which lead to loss increasing, hightemperature and other problems. Three key technologies that slotcombination, the using of magnetic slot wedge, the ventilation structureaiming at the problems are studied and designed. The contents and results areas following1. Aiming at the problem of the electromagnetic noise which was led bythe improvement of magnetic loads, the radial force waves which generateelectromagnetic vibration and noise were analyzed. The radial force waves indifferent slot combination were probed based on the effects on theelectromagnetic vibration of different slot number. Then a new slotcombination project was confirmed and the rationality of it was verified bythe simulation.2. With the problem of the efficiency because of the increasing ofmagnetic loads and the diffidence of slot combination, the beneficial effectsof magnetic slot wedge on the generator were studied and simulated. Thereasons which cause magnetic slot wedge failure were analyzed based on the forces magnetic slot wedge suffered in electromagnetic field. The forcessuffered in various fault conditions were calculated. The results provideguidance to the application of magnetic slot wedge.3. For the problem of temperature rise, the principle of ventilation andthree ventilation and cooling systems were probed. The ventilation structurewas calculated by CFD simulation software. The rotor axial ducts’ numberand structure were improved based on the fluids flow inside the generator.The optimal ventilation structure was confirmed by simulation andcomparative analysis. The temperature distribution of high power densitysquirrel cage wind power generator was solved effectively.Finally, according to the design, relative experiments were did based onthe prototype produced by Shanghai Electric Machinery Corporation. Theperformance indicators were verified and the reliability of the generator wasensured.