volume | PIER Journals

Abstract

The impact of permanent magnet (PM) properties such as magnetremanence and coercive force or coercivity on the electromagnetic output of flux-switching permanent magnet machine having C-core stator topology is presented and compared in this work. A two-dimensional finite-element analysis (2D-FEA) approach is implemented using ANSYS-MAXWELL software package. Three-dimensional (3D) FEA calculations are also conducted, in order to realize more accurate results, and its results are compared with the 2D-FEA predicted results. The investigated machine elements are: airgap flux-density, torque ripple, total harmonic distortion (THD) of the voltage, cogging torque, unbalanced magnetic pull (UMP) or force, winding inductances, direct- and quadrature-axis flux, electromotive force and output torque. The analyses show that undesirable qualities such as large amount of cogging torque and UMP are predominant in the machine having rare-earth magnets i.e. neodymium and samarium-cobalt, although they have larger flux linkage and superior average torque compared to its non-rare-earth magnet equivalents i.e. the ferrite- and alnico-made machines. Moreover, the alnico- and ferrite-made machines exhibit larger winding inductance values, and consequently lower saturation withstand capability, though with better field-weakening capability. Further, the predicted efficiencies of the compared machine types having alnico, ferrite, neodymium and samarium materials, at rated current and speed conditions are: 79.8%, 75.76%, 87.22% and 86.58%, respectively. More so, the generated electromagnetic output power of the compared machine types at the operating base speed is: 206.57 Watts, 186.57 Watts, 449.67 Watts and 396.40 Watts, respectively. The investigated machine is suitable for high torque in-wheel direct-drive applications.

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Dr. Stephen Ejiofor Oti

Dr. Chukwuemeka Chijioke Awah