Comparative Study On Mechanical And Electromagnetic Performances Of High Speed IM With Different Rotor Structures

The high speed induction machine has been widely investigated since it has small size, high efficiency and power density. The permanent magnet material has small tensile strength and cannot withstand the large centrifugal force due to the high rotation speed, so the mechanical performances of the permanent magnet machine are poorer than the induction machine's. At the same time, the electromagnetic performances of the reluctance machine are poorer than the induction machine's. So the induction machine for high speed operation has the actual significance. For the characteristics such as high speed and high frequency, the paper pays attention to the following questions:The dimensions of the high speed induction machine with different rotor structures are calculated first. Then the mechanical strength characteristics of the high speed induction machine with four kinds of rotor structures are analyzed based on Ansys. The application situations in which different rotor structures are used are analyzed by the mechanical performances. The critical speed of solid core rotor induction machine is calculated.The electromagnetic field of high speed induction machine is studied based on Ansoft. The electromagnetic performances of the high speed induction machine with the same stator dimension and different rotor structures are analyzed comparatively. The stator losses and rotor losses are calculated by FEM. The application situations in which different rotor structures are used are analyzed by the electromagnetic performances.The iron loss calculation method of traditional machine is not fit to high speed machine. The loss coefficient in the high frequency is measured by the no-load experiment of the silicon sheet. So the stator core loss of the high speed induction machine is calculated more accurately.Because the high speed machine has small size and power density, the temperature rise is a critical problem that has to be solved. The temperature rise of the solid core rotor structure induction machine is calculated.