Research Of Low-voltage MW-rate Multi-branch Permanent Magnet Synchronous Motor

In the system which driven by high-voltage AC motor, there are many disadvantages such as insulation, power supply, control and so on. People are searching the solutions to these problems for many years. In this thesis, a novel multi-branch idea is reported: low-voltage MW-rate multi-branch permanent magnet synchronous motor (PMSM). The stator windings of this PMSM are designed to multi branches, and these branches compose independent windings, the stator current can be separated. The main work includes four parts:By analyzing the characteristics of the multi-branch PMSM and the design theory of PMSM, the voltage equation, flux linkage equation, torque equation and so on of the multi-branch PMSM is given. And the main characteristic of the stator winding in multi-branch PMSM is reported.The design procedure for the multi-branch PMSM is adopted to design a 30kW, 8 poles, 8 branches prototype. And the design process and the design principle of parameters are presented detailed.Make use of the finite element analysis software to set up the 2D model of the prototype. By analyzing the status that all of the branches are put into work and get magnetic field distribution, speed curve and so on. And contrasting the simulation results with the design proposal. Then, analyzing the status which different quantity and different positions branches are put into work. Getting the magnetic field distributions and the speed curves in different status. These prove the multi-branch idea is feasible in theory.An experiment platform has been designed and built, and some experiments have been make on the prototype. Including measuring the self inductance of phase A and the mutual inductance between phase A and B, C; self inductance of branch and mutual inductance among branches; electromotor no-load experiment; measuring the electromotor loss; using valley current method to mensurate the no-load back electromotive force; temperature rise experiment and electromotor load experiment. Above all things, the experiment on the process of branch launching and cutting verify the branches can separate the stator current reliably, and the multi-branch idea feasible virtually.