Design And Loss Analysis Of MW-level High Speed Permanent Magnet Synchronous Machine

High speed machine can directly drive high speed device and decrease the volume ofthe drive system, improve the efficiency and reliability of system. Moreover, it is easy toinstall and maintain. In addition, high speed machine possess the many advantages, such ashigh power density, small moment of Inertia, fast dynamic response, small geometry size,which is far less than the machine in the same power level, and so on. High speed machinecan been widely used in hybrid cars, high speed grinding machine, centrifugal compressor,flywheel energy storage and distributed power generation system presently. As for itsadvantages and characteristics, a series of new problems and new difficulties appear indesigning high speed machine.Firstly, on the basis of studying the design features of high speed machine, it isstudied deeply that the selection of stator structure, stator material, pole number, permanentmagnet material, the protection of permanent magnet. Moreover, the preliminary designscheme is determined and it is studied that the influence of different main dimensions,different slot number and different air gap length on machine performance. Throughanalyzing the advantages and disadvantages of different schemes, the main factor thatinfluences the machine performance is summarized.Secondly, magnetization characteristics of the high speed machine stator iron loss arestudied deeply, and know that it is irregular rotation magnetization. Based on theorthogonal equivalent analysis of rotating magnetic field, this paper presents one kind ofcalculation method of stator iron losses with considering the rotating magnetic field andharmonic field. By fitting the loss curve of stator core material with least square method,the coefficient in the calculation method is acquired. Using the given method, the iron lossunder different frequencies is calculated. Moreover, the feasibility of the method is verifiedthrough comparing the calculation results with the results of conventional iron losscalculation method and Ansoft software. In addition, due to the serious skin effect and proximity effect of high speed machinewinding, which affect winding copper loss significantly, the skin effect and proximityeffect of conductor are studied deeply. And the main factors that affect the skin effect andproximity effect are summarized. Using Ansoft software, It is studied that the effect ofdifferent current frequency and different number of wires per conductor to winding ACloss of the machine.Finally, the final design scheme of MW-level high speed permanent magnetsynchronous machine is given. Through analyzing the two dimensional magnetic field ofthe machine, the electromagnetic performance curve of the machine under no-load andfull-load. To ensure each part temperature of the machine under full-load not too high, thestationary temperature rise of the stator and rotor under full-load are calculatedrespectively with2D finite element method and the temperature distribution of the machineis acquired.