Comparative Thermal and Demagnetization Analysis of the PM Machines with Neodymium and Ferrite Magnets

Abstract

This paper provides computer analysis and experiential investigation of the permanent magnet machines with neodymium and ferrite permanent magnets to discuss the feasibility of utilizing induction machines-oriented equipment for PM machine production. For this purpose, the machines are obtained by replacing the squirrel-cage rotor of the induction motor with the flux-focusing (tangential) and surface-mounted (radial) permanent magnet rotors. Electromechanical parameters of the machines as electromagnetic torque and output power are discussed and compared. The temperatures of the neodymium and ferrite magnets are also calculated at rated current, and short circuit scenarios and the performance of two different cooling systems in minimizing the temperature effect on the machines are investigated. Furthermore, the demagnetization of permanent magnets at various load conditions is also studied. Finally, the results of the computer modeling are validated by the physical prototypes of the machines. The characteristics of the electrical machines under study were calculated using the Simcenter MagNet and Simcenter MotorSolve software packages.

Overview on Permanent Magnet Motor Trends and Developments

“…Magnets of this type have a higher jHc value and are therefore more difficult to demagnetize than ND50H magnets and in that respect, even more difficult when related to the original simulation of the machine with ND52 magnets. In order to keep the torque performance of the machine the same, the length of the machine has to be increased, since the Br value of the magnets is reduced [77]. The demagnetization behavior of this machine with ND42UH magnets, as shown in the diagrams below, is much more robust than the previous two machines.…”

Comparative analysis of the power parameters of a line start permanent magnet synchronous motor using professional FEM packages and in-house software

“…There are professional FEM software packages for electromagnetic field calculations, including JMAG-Designer [8], ANSYS Maxwell [9,10], Simcenter MAGNET. [11,12], COMSOL Multiphysics [13,14], Opera SYMU-LIA [15,16], Flux 2D [17,18] or its three-dimensional variant Flux 3D [19,20]. Using some of the above-mentioned FEM packages, the author has prepared and repeatedly tested independently developed FEM-based software for calculating the electromagnetic field distribution in electrical machines with permanent magnets and squirrel cage windings.…”

On the Usefulness of Employing ANSYS Motor-CAD Software in Designing Permanent Magnet Synchronous Machines

“…Electrical machine designers have at their disposal numerous software tools to ease and improve their challenging engineering work. Most of them are using professional finite element analysis (FEA) software products for numeric electromagnetic field computations [7,8], such as JMAG-Designer [9,10], ANSYS Maxwell [11,12], Simcenter Magnet [13,14], COMSOL Multiphysics [15,16], Flux 2D [17][18][19] or its three-dimensional variant Flux 3D [20,21]. All such programs can perform precise computations for obtaining the magnetic field distribution within the electric machine, the generated forces, magnetic, material-related, and dynamical parameters, etc.…”

“…[27]. Another similar software product, Simcenter Motorsolve, has an easy-to-use template-based GUI for defining a great diversity of electrical machine topologies, which can be analyzed by applying both equivalent magnetic circuit-based calculations and FEA [14,28].…”