Comparison Research of Hybrid Excitation Synchronous Generator between Uniform and Nonuniform Rotor Structure

In this paper, a hybrid excitation synchronous generator(HESG) with non-uniform rotor structure is proposed, whose flux density and operation characteristics are compared to that of uniform rotor structure. The rotor of the proposed HESG is composed of two solid claw poles, rotor yoke and the permanent magnets (PMs) which have both tangential and radial structures. It is not easy to assemble the rotor directly. Therefore, it is proposed to excavate slots on the flange disc of the claw poles, it is also necessary to ensure that the slots and the PMs are of the same size and position. This new design method not only reduces the difficulty of rotor installation, but also does not need glue to fix PMs, which is more environmentally friendly. Firstly, the paper compares the installation methods of rotor structure in two cases, and describes its operation principle. Then, the flux density distribution, flux density of air-gap and related components are analyzed by three-dimensional finite element method. It can be obtained that the flux density of non-uniform rotor structure is divided into blocks. In addition, the output voltage, operation characteristics and core loss on stator and rotor are analyzed and compared. Finally, the HESG with non-uniform rotor structure is prototyped to verify the results of the finite element analysis.