Study On Transverse Flux Permanent Magnet Wind Generator With Double-C Stator And Flux Concentrated Rotor

Transverse flux permanent magnet machine (TFPMM) is suitable for the direct-drive wind power generation for the merits of large torque capability and high power density. TFPMM becomes an up-to-date research hotspot in the field of electrical machine, which brings a complete solution to the ever-present contradiction between the increases of magnetic flux and winding current in the same plane in traditional radial flux and axial flux PM machines.Based on the deep analysis of the existing TFPMM structures an integration of one winding armature couples to two groups of C-type stator hoops is created. The novel transverse flux permanent magnet generator with double-C stator and flux-concentrated rotor (DSFCR-TFPMG) is proposed in this dissertation, which has advantages of more compact structure, better utilized permanent magnet and silicon steel lamination, and higher overall space utilization. The flux concentrated rotor enhances the efficiency and power density also and therefore the generator is more suitable for low speed direct drive wind power generation system.Due to the decoupled electric load and magnetic load of the TFPMM the cross-sectional area of the coil, the capacity of the magnetic circuit and the pole numbers can be determined as necessary for the purpose of enhancing the utilizations of the material and the space effectively, thus the power density and the torque density can be significantly increased.The objectives of this study are to establish the fundamental theory and design approach of the DSFCR-TFPMG, to verify the theoretical analysis, and to enrich experiences for both fundamental research and applied development of TFPMM. The research work has made some breakthroughs and progresses, which provide a mathematical model and some experimental data for the development of large-scale wind generator. Furthermore, the study on such new type special machine promotes the theory application and the engineering development.The topology, dimensions, operation principle, and electromagnetic parameters of the generator are illustrated in details. The three-dimensional (3D) finite element method (FEM) is employed to compute the no-load and load magnetic field distributions and the parameters of flux density, back electromotive force and armature winding inductance. The mathematical relationships among the parameters are summarized and some design rules are generalized.The mathematical model of DSFCR-TFPMG is deduced. The key technology of electromagnetic calculation and size optimization of the generator are invesigated. The optimization strategy of the new type generator is explored. The experiences of the specific design rules and methods of the generator are accumulated. A single-phase and a three-phase DSFCR-TFPMG prototypes are fabricated and the experiments are conducted to verify the design method and the prototype structure. The parameters are optimized for the targets of improving the performance of the generator by enhancing the torque density, increasing the power factor and reducing the cogging torque.A wind turbine model is established by an induction motor in simulation method under the laboratory condition. The maximum power point tracking (MPPT) strategy is implemented through the research. The grid-connected wind power systems, especially of doubly fed induction generator (DFIG) and direct-drive synchronous generator (DDSG) are depicted. The DSFCR-TFPMG based soft switching inverter are constructed and simulated to explore the feasibility and effectiveness of the DSFCR-TFPMG based direct drive wind power sysytem. Through the overall control the system efficiency is improved to ensure the stable operation of the grid-connected system.