Research On Technology Of Demagnetization Proof Of Permanent Magnet Machine On High Temperature

This dissertation is devoted to the study on the reasonable select of permanent magnet, effect on permanent magnetic machine of permanent magnetic(pm) material and test methods and equipment of thermal stability in order to resolve the demagnetization problem of pm machine which have obtained some achievement on theory and engineering application. This project is supported by the National Key Technologies R&D Programme and the Science and Technology Items of Liaoning province and Shenyang city and is a part of the item "commonness key technique of rare earth PM material application on high performance electrical machine " in rare earth application engineering.Four parts are included as follows:First of all, lots of permanent magnetic samples are measured and results and factors affecting accuracy in the course of measurement are analyzed. Parameters of pm material affect directly the performance of pm machines. In order to find out the performance actuality of pm material, lots of permanent magnetic samples are measured. Basing on the analyzing of measurement results, there are more difference on the performance of pm material. The difference behave on uniformity, coherence and thermal stability and exists in not only different manufactories but also different batch materials produce in same manufactory. The difference not only increases the difficulty of machine design but also reduces the reliability of pm machine. In the results, thermal stability is emphasized. The analysis results provides data base for pm machines design. Basing on the measurement results before and combined with the relationship of magnetic parameters of permanent magnet and the character of demagnetization curve, calculating formulas of the position of knee point and temperature coefficient were analyzed and given. By the formulas, not only the position of knee point on working temperature can be calculated from the magnetic parameters given by the material factory but also the inherent coercive force can be calculated from the determinate position of knee point on working temperature. The application of the formulas make the selection of permanent magnetic materials more particular.Secondly, the non-destruction measurement technique of thermal stability of pm material is researched and several methods were brought forward. In order to meet the needs of more manufactories, two methods are brought forward and corresponding apparatuses are designed. The application of methods and apparatuses not only can keep the integrality of permanent magnetic materials avoiding the waste brought about by the incision but also can decrease the cost of the device and measurement time to meet the needs of manufacture in practice.The third part devoted to the effect of permanent magnetic material parameters on pm machine design and put forward the specification of demagnetization proof of permanent magnet machine on high temperature. The specification is put forward from the selection of permanent magnet materials, appropriate design of rotor, calculation of maximal demagnetization working point three facets. Being as a source of flux or magnetic motive force, pm material affects the performance of pm machines. On definite temperature, the knee point of pm material affects not only the volume of material but also the reliability of pm machine. In order to ensure electrical machine's reliable operation, the maximal demagnetizing working point of permanent magnet material should be above the knee point. If the knee point of pm material is high, the volume and cost must increase accordingly.