| Harmonic magnetic fields are main reason of motors’stray loss and electromagnetic noise, calculation precision of harmonic magnetic fields will affect analysis of motors’stray loss and electromagnetic noise directly, it is very meaningful to research the analysis method of motors’harmonic magnetic fields. Analytical calculation of harmonic magnetic fields has forthright process, can get expression with clearer physical concepts, but it made a number of simplifications, for example cogging effect, iron core saturation effect, etc, that can produce a certain error. Electromagnetic field finite element method can deal with problems, for example, complex motor structure, nonlinear of ferromagnetic material, etc. it is an accurate calculation method of harmonic magnetic field.With practice of using finite element analysis software of ANSYS, analysis on stator harmonic magnetic fields of motors based on electromagnetic field finite element calculation was summarized and proposed. The method can achieve purpose of analyzing and calculating harmonic magnetic field accurately and conveniently, it is an important innovation, it has theoretical significance and application value.Firstly, analytic expression of radial force wave formula of PM motors was derived under sine wave power supply circumstance, harmonic magnetic fields and radial force wave were analyzed. Harmonic magnetic field analysis of motors through using finite element analysis software of ANSYS was proposed, idea and realization way of analysis on stator harmonic magnetic field was particular introduced in software. In the finite element analysis software of ANSYS, problem that magnetic fields’harmonic number can no judge was solved, harmonic magnetic fields were selected based on conditions through writing VBA code, making Excel for analysis on air gap harmonic magnetic field of motors’.Secondly, stator harmonic magnetic field of motors with 60° phase-belt winding, 120° phase-belt winding and unequal-turn numbers winding was analyzed through using finite element analysis software of ANSYS, harmonic number and harmonic magnitude/fundamental magnitude of MMF and magnetic field were contrasted and analyzed, effect of magnetic leakage, iron core saturation and iron core slot for stator magnetic field were discussed, analysis result shows that harmonic analysis of MMF and magnetic field are basically consistent, stator harmonic magnetic fields include three-multiple harmonics under iron core saturation circumstance, analysis result verifies analysis method of stator harmonic magnetic field of motors based on electromagnetic field finite element calculation is accurate.Finally, analysis method on harmonic magnetic field of motors based on electromagnetic field finite element calculation was applied to analyzing the radial force wave of PMSM with fractional-slot concentrated winding, MMF and harmonic magnetic fields of slot/pole number combination of 30/32,33/32 and 36/32 was contrasted and analyzed, the 36/32, optimal slot/pole number combination was identified, the proposing analysis method of harmonic magnetic fields can analyze harmonic magnetic fields and radial force wave of PMSM with fractional-slot concentrated winding forthrightly and accurately. |
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