Composite Rotor Induction Motor Electromagnetic Calculation

With the development of power electric technology, asynchronous motor has show excellent performance as generator in a high voltage DC independent supply systems. Solid rotor induction motor have simplest structure and strangest rotor, adapt for running at high speed, has smaller ratio of starting torque to current comparing to a common asynchronous motor. So it may be a best choice, using a solid induction motor in high speed starter/alternator system. However, solid rotor induction motor has a poor performance, and the research of it focuses on improving its performance.There are two factors leading to the poor performance. One is that copper loses on rotor side is larger than a lamination rotor. The other is that it has a larger stray lose. From the two points, electromagnetic calculation was carried out in this thesis.A larger stray lose on solid rotor caused by its integer construction with a larger surface eddy current loses excited by harmonic. The fundamental of harmonic forming is analyzed firstly. Then the magnitude of harmonic is computed by analytic method. Base on the work above the influences of slot opening and air gap clearance on stray lose are analyzed.Because of smaller conductance, solid rotor has a larger copper loses. The measures to improve that mainly are taken on rotor. There are several types of motor derived from the prototype motor. In this thesis, several types of solid induction motor are compared and a caged solid rotor induction motor was computed by using finite element method. The result under nonlinear eddy current field has showed that this type motor's performance is near to a usual asynchronous motor and worth further researching.Base on the reaching above and the other's earlier work, electromagnetic designing of caged solid rotor induction motor was discussed.