Research And Design Of Permanent Magnet Suspension Wind Power Generator Rotor

For applying magnetic suspension technology to rotor system of the traditional wind power generator, its mechanical bearings will be replaced by magnetic bearings. It can reduce friction force and the friction moment between the rotor and bearings drastically, realize the virtue of wind power generator: "the light wind can start, the breeze can generate electricity", and can expande the utilization of wind resources, raise the generating efficiency, avoid the high expense when using and maintaining mechanical bearings, reduce the cost of wind power generation. So for our country it is of advantage to widespread application of wind power generation and development of wind business, and contributes to the project of energy conservation and pollution reduction. Therefore, the research of magnetic suspension wind power generator rotor has important practical significance.With the development and application of magnetic suspension technology, there are mainly three kinds of suspension system, such as active magnetic suspension, passive magnetic suspension and hybrid magnetic suspension. In terms of technical difficulty, cost and maintenance, it is reasonable to adopt the passive magnetic suspension system in magnetic suspension wind power generator rotor. In view of the small horizontal axis wind power generator, a kind of magnetic suspension wind power generator rotor was researched and designed, it was supported by permanent magnet bearings in radial direction, and constrained the small ball fixed in ends of axis with mechanical force in axial direction by adjusting axial displacement between inner magnet rings and outer magner rings, and then it was suspended stably.The stability of wind power generator rotor system has the very tremendous influence to the power supply reliability as well as the electric network stability, so it is necessary for magnetic suspension rotor system to have the good reliability and the stability, that is to say, the permanent magnet bearings should have the high bearing capacity and the rigidity. Because of limited bearing capacity for permanent magnet bearing composed of single ring, the axial position multi-ring superposed permanent magnet bearings have been used to enhance its radial bearing capacity and radial stiffness in the thesis. Taking the position (B_d,H_d) where NdFeB permanent magnet material obtains the biggest magnetic energy product as the static operating point, the sectional dimension of magnet rings and magnetic circuit of permanent magnet bearings have been analyzed and designed with the method combining magnetic path calculation and finite element calculation.When considering magnet rings curvature and magnetization direction, mathematical models of bearing capacity of permanent magnet bearings composed of single ring and multi-ring were established respectively basing on equivalent magnetic charge theory, which can reflect axial displacement's and radial partiality's influence to bearing capacity obviously.The prototype of permanent magnet suspension wind power generator have been researched and designed, among which the installation of multi-ring superposed permanent magnet bearings and adjustment of permanent magnet suspension rotor have been mainly considered. Finally, taking rigidity produced magnet by unit volume of permanent magnet bearings as the objective function, carried on the optimization to the height h and amount n of magnet ring, and proposed a plan of optimization to the regulating organ of rotor.