Design And Magnetic-Thermal Analysis Of High Power Density Permanent Magnet Synchronous Motor

In recent years, the permanent magnet synchronous motor performance has been greatly improved because of the emergence of high performance NdFeB, samarium cobalt and other rare-earth permanent magnetic materials. The permanent magnet synchronous motor has many advantages of high power density, high efficiency, small volume, low noise, which is widely used in industrial production. Due to the excellent performance and strong demand of permanent magnet synchronous motor, the design and development of high performance permanent magnet synchronous motor has become a hot research topic at home and abroad.This paper designed a rated power of 15 kW, within quality 20 kg and short-time duty special permanent magnet synchronous motor. Describes the structure and working principle and characteristics of high power density permanent magnet synchronous motor, analyzes the differences between the high power density permanent magnet synchronous motors and general motors in design. Due to the operating time is short, special cooling method didn't been designed. Considering motor capacity to withstand high temperatures, resistant high temperature materials have been used in high power density permanent magnet synchronous motor to ensure that the motor still can continue to work normally under high temperature. According to the design principle of permanent magnet synchronous motor, the main dimensions, winding, slot and pole number, permanent magnet and stator slot dimension of permanent magnet synchronous motor are designed. The simulation model of electromagnetic field is established by the finite element analysis software MagNet. The motor static magnetic field and winding back EMF, cogging torque, steady state operation has been simulated and got the electric characteristics results of permanent magnet synchronous motor. At the same time, combining the results of software simulation to the overall design of permanent magnet synchronous motor repeatedly determined the electromagnetic design scheme ultimately.The motor watt density is 0.906 kW/kg and no special cooling method, so the temperature rise is serious. Although the high temperature resistant materials has been used, the permanent magnet synchronous motor design success or not need to analyze temperature rise. The heat transfer science basic theory has been introduced, including heat conduction, heat convection and heat radiation, heat capacity and thermal resistance concept. Analyzed the various loss in permanent magnet synchronous motor resulting temperature rise, including stator iron loss, winding loss, machine loss and permanent magnet eddy current loss. Finally, the thermal simulation model have been built by temperature field simulation software ThermNet. The high power density permanent magnet synchronous motor at rated load and no-load temperature field were simulated by coupling with MagNet, and analyzed the temperature rise results.