Design And Research Of 100kW Hybrid Excitation Permanent Magnet Synchronous Wind Generator

The hybrid excitation generator differs from the permanent magnet synchronous generator and the traditional electric excitation synchronous machine with structure. This structure has not only magnet but also electric excitation winding. It means that the generator has two MMF sources. It concentrates their advantages:the little adjustable magnetic field capacity and high efficiency, and overcomes the defect that it is difficult to adjust the air-gap flux density for a permanent magnet machine. So the hybrid excitation generator is worthy to be promoted and applied.The main study contains three parts:to keep constant voltage with variable speed, to decrease the starting resistant moment, to raise efficiency. The corresponding technological difficulties are these:the complicated magnetic circuit structure, the cogging torque caused by permanent magnet and the influence to efficiency by copper loss. The solutions are submitted in this paper.The theoretical basis of design about permanent-magnetic circuit and electro-magnetic circuit are suggested for this magnetic circuit structure, and the detailed project succeeds. For the design of the prototype, first the choice of slot and pole number combination is done from the winding factor, the cogging torque, harmonic of MMF, asymmetric radial magnetic pull force, fault-tolerant, eddy current losses and so on. Then the combinations of pole and slot as 40 poles 42 slots,40 poles 45 slots and 40 poles 48 slots are compared. The combination of 40 poles 45 slots is selected after comparisons of inherent voltage regulation-rate, efficiency, characteristics of keeping constant voltage and effective material usage. In the area of the main dimensions, the paper mainly introduces the identification of the permanent magnet, back yoke, air gap, pole-arc coefficient, and the design of electro-magnetic, and so on. Some expositions are done for the prospective silent tank structure and the modular structure. On the basis of the detailed sizes of the machine, the model is established from using the finite-element software of Ansoft. The analysis of the magetostatic field, the transient field and the external circuit is done to verify the rationality of the design. Depending on the design, a prototype of hybrid excitation permanent magnet synchronous generator with rated power 100kW is manufactured, and the systematic test and analysis is done. Through analyzing the test data of prototype and comparing with the results of magnetic circuit calculation and finite element simulation, the correctness of equivalent magnetic circuit and the accuracy of finite element analysis is validated, and the feasibility of the prospective silent tank structure. The starting resistant moment and the efficiency can reach the scheduled targets. It is able to keep exporting a constant voltage for the prototype in the predetermined speed range, even much winder range of speed. In a word, the prototype is done well achieved the performance requirements.