Research On A Radially Magnetized Permanent-Magnet Linear Generator Used For Hybrid Electric Vehicles

The permanent-magnet linear generator in this thesis will be used in a series hybrid electric vehicle schemes as an auxiliary power generating unit(APU),which is connected with a free-piston combustion engine. This research is very popular because of the light weight, compact configuration, less energy loss and higher efficiency of the new system. Some research has been carried out on the permanent-magnet linear generator.Firstly, after introducing the configuration and the theory of the permanent-magnet linear generator, based on the finite element method (FEM), a FEM model of the permanent-magnet linear generator is established.Then, the generator is optimized from three aspects. The first aspect is the material selection used for the stator core. Iron loss is a big part of the machine loss and has a great act on the efficiency. So a good choice is needed. The second aspect is the arrangement of the magnets. It can decide whether the magnetic density distribution in the stator and translator iron is even. The last one is the dimension of the generator. It also has a great act on the performance of the generator.The cogging force appears in all linear machines and is a big drawback of linear generator. After explain how to calculate the cogging force, the thesis analyzes some methods how to reduce the cogging force and the force ripple, such as the optimization of the pole embrace, the width of the side magnets and the width of the teeth.At last, the thesis does some research on the two different ways of the stator lamination, i.e., radial lamination and axial lamination. The different manufactures and the equivalent magnetic circuits are introduced, and the FEM models are established. And then the performance is calculated and compared.