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Shen Y.,University of Sheffield | Zhu Z.Q.,University of Sheffield | Chen J.T.,University of Sheffield | Deodhar R.P.,Imra Europe Sas Uk Research Center
PEDES 2012 - IEEE International Conference on Power Electronics, Drives and Energy Systems | Year: 2012

Nowadays, the replacement of rare-earth permanent magnet is one of the primary targets to enhance the cost-effective design for electrical machines. A claw-pole rotor brushless machine with DC excitation is desirable as a magnetless machine because it is reliable, low-cost, and does not need slip ring etc. However, the inherent 3D structure makes numerical analysis very time-consuming. In this paper, a lumped-parameter magnetic circuit model is developed to model and design an 18-slot/6-pole claw-pole rotor brushless machine with DC excitation, while its validity is examined by using 3D finite-element analysis. The optimization is also carried out, together with optimal skew and unequal rotor pole thickness. © 2012 IEEE. Source


Shen Y.,University of Sheffield | Zhu Z.Q.,University of Sheffield | Chen J.T.,University of Sheffield | Deodhar R.P.,Imra Europe Sas Uk Research Center | Pride A.,Imra Europe Sas Uk Research Center
IEEE Transactions on Magnetics | Year: 2013

Since the claw-pole machines can exhibit a number of attractive features, they have been widely applied to automotive and domestic markets. Nowadays, with the development of rare-earth permanent magnet (PM) and powder metallurgy techniques, high performance and cost-effective design of a multiphase claw-pole stator SPM brushless machine becomes achievable. However, the inherent 3-D structure makes finite-element analysis very time-consuming. Thus, a lumped-parameter magnetic circuit model is developed and validated by 3-D finite element analysis in this paper to design three-phase 10-pole claw-pole stator surface-mounted PM brushless machine having soft magnetic composite made stator core. A prototype machine is built and tested in accordance with analytically optimized overall design parameters. © 2013 IEEE. Source


Liu X.,University of Sheffield | Zhu Z.Q.,University of Sheffield | Hasegawa M.,Imra Europe Sas Uk Research Center | Pride A.,Imra Europe Sas Uk Research Center | And 3 more authors.
IEEE Energy Conversion Congress and Exposition: Energy Conversion Innovation for a Clean Energy Future, ECCE 2011, Proceedings | Year: 2011

Although different drive topologies have been developed for switched reluctance machine (SRM), the inherent disadvantages, including high dc-link voltage and current pulsations and low drive efficiency, in addition to relatively high torque ripples and acoustic noise and vibration, have limited their application to many applications. To solve this problem, the SRM may be operated as a synchronous reluctance machine but with concentrate winding, and the vector control strategy can then be employed. Compared with conventional unipolar excitation in SRM, it has the advantages of significant reduction of dc-link capacitance, moreover, lower noise and vibration and higher efficiency are also achieved. In this way, it is possible to replace the electrolytic aluminum capacitors with the film ones, which results in much lower cost and higher reliability of the whole drive system, which is very attractive for many applications. Experimental results on a prototype 6/4 SRM validate the effectiveness of sinusoidal bipolar excitation. © 2011 IEEE. Source


Liu X.,University of Sheffield | Zhu Z.Q.,University of Sheffield | Hasegawa M.,Imra Europe Sas Uk Research Center | Pride A.,Imra Europe Sas Uk Research Center | And 3 more authors.
IEEE Energy Conversion Congress and Exposition: Energy Conversion Innovation for a Clean Energy Future, ECCE 2011, Proceedings | Year: 2011

In this paper, the electromagnetic performance of switched reluctance machines (SRMs) with unipolar and bipolar excitations, either sinusoidal or rectangular current waveforms, is investigated in terms of torque capability and torque ripple, iron loss etc. By employing a cost effective standard 3-phase full bridge inverter, both rectangular and sinusoidal bipolar excitations are implemented. Compared with unipolar and rectangular bipolar excitations, the torque ripple and iron loss are significantly reduced with sinusoidal bipolar excitation, albeit with reduced torque capability. Experiments on a prototype 6/4 SRM are carried out to demonstrate the advantages of sinusoidal bipolar excitation. © 2011 IEEE. Source


Liu X.,University of Sheffield | Zhu Z.Q.,University of Sheffield | Hasegawa M.,Imra Europe Sas Uk Research Center | Pride A.,Imra Europe Sas Uk Research Center | Deodhar R.,Imra Europe Sas Uk Research Center
Conference Proceedings - 2012 IEEE 7th International Power Electronics and Motion Control Conference - ECCE Asia, IPEMC 2012 | Year: 2012

The vibration and acoustic noise are investigated in a novel variable flux reluctance machine, which utilizes a DC-field coil in the stator to achieve on-line adjustment of air-gap flux density. The capability of adjusting air-gap flux density is expected to improve the efficiency and extend the speed range. The doubly salient structure in switched reluctance machines (SRM) is employed in the variable flux reluctance machine, together with the non-overlapping concentrated windings to reduce the copper loss. The 2D and 3D-finite element analyses are employed to predict the radial force and vibration modes in the variable flux reluctance machine, respectively. With the aid of vector control, which employs space vector pulse-width modulation, the vibration and acoustic noise in this novel machine are experimentally investigated, together with the comparison with SRM, which has the same stator/rotor pole combination. Compared with SRM, under the same load condition, the variable flux reluctance machine significantly reduces the vibration of mode 2, which is dominant in the SRM. © 2012 IEEE. Source

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