Finite Element Analysis And Demagnetization Of Interior-asynchronous Starting Permanent Magnet Synchronous Motor

Interior-asynchronous starting Permanent Magnet Synchronous Motors are widely used in various fields because of their high efficiency,low usage of permanent magnets,low cost of motors and having self-starting ability.Taking an Interior-asynchronous starting Permanent Magnet Synchronous Motor as the research object,this paper mainly studies from parameter calculation,electromagnetic field analysis,temperature field analysis and demagnetization analysis of permanent magnets.Specific studies are as follows:1.For the prototype being studied,the torque-angle curves and inductance curves under different currents and the no-load back electromotive force at different speeds are measured experimentally.Then the torque-angle curve clusters and the direct axis and quadrature axis inductances under different currents and the permanent magnet flux are obtained.The experimental results are consistent with the results of finite element numerical calculations,which proves the correctness of the experimental results.2.The two-dimensional finite element model is established by using finite element analysis software-Ansoft,and the transient self-starting process of the motor is analyzed.Using maxwell circuit to build the external circuit,the short circuit faults of the motor during the running process are realized by the voltage control switch,and the change of the torque,speed and current are analyzed.The copper loss,stator core loss and permanent magnet eddy current loss under different working conditions are calculated.3.In the temperature field calculation software-ANSYS Mechanical APDL,a two-dimensional full model is established.The stator winding copper loss,stator core loss,and permanent magnet eddy current loss are used as the heat source,and the steady-state temperature field distribution of the motor is calculated.4.In the electromagnetic field,the magnetic flux density of permanent magnets from the start of short circuit faults to the steady state is calculated,and the minimum magnetic flux density of each point of the permanent magnets is extracted to generate the magnetic cloud image,which is the basis for judging the demagnetization.If the minimum flux density under different short circuit faults is lower than the knee-point magnetic density of the demagnetization curve,the permanent magnet in the region is demagnetized.The demagnetization of permanent magnets under no-load and rated load and under different short circuit faults is studied.