TY - JOUR
T1 - A thermal improvement technique for the phase windings of electrical machines
AU - Galea, Michael
AU - Gerada, Chris
AU - Raminosoa, Tsarafidy
AU - Wheeler, Patrick
N1 - Funding Information:
Manuscript received June 2, 2011; revised August 16, 2011; accepted September 11, 2011. Date of publication November 9, 2011; date of current version January 20, 2012. Paper 2011-EMC-354.R1, presented at the 2010 XIX International Conference on Electrical Machines, Rome, Italy, September 6–8, and approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the Electric Machines Committee of the IEEE Industry Applications Society. This work was supported by the “EU FP7 funding via the Clean Sky JTI-Systems for Green Operations ITD”.
PY - 2012/1
Y1 - 2012/1
N2 - In electrical machines, a higher torque/force density can usually be achieved by increasing the current density in the windings. However, the resulting increase in copper losses leads to higher temperatures in the coils, particularly in the center of the slots where the thermal resistance to the ambient/cooling surfaces is highest. In this paper, a novel, simple technique is presented in which a higher thermal conductivity path between the center of the slot and the cooling arrangement is created, thus increasing the heat flow away from the slot center. A lumped-parameter thermal model is presented and used along with finite-element analysis to investigate the effectiveness of the proposed technique. The lumped-parameter model is also used for optimizing the high conductivity path for maximum air-gap shear stress and to obtain a compromise between the reduced slot area and the improved temperature distribution. Experimental validation is then presented to compare the predicted results with the measured results on a purposely built instrumented setup.
AB - In electrical machines, a higher torque/force density can usually be achieved by increasing the current density in the windings. However, the resulting increase in copper losses leads to higher temperatures in the coils, particularly in the center of the slots where the thermal resistance to the ambient/cooling surfaces is highest. In this paper, a novel, simple technique is presented in which a higher thermal conductivity path between the center of the slot and the cooling arrangement is created, thus increasing the heat flow away from the slot center. A lumped-parameter thermal model is presented and used along with finite-element analysis to investigate the effectiveness of the proposed technique. The lumped-parameter model is also used for optimizing the high conductivity path for maximum air-gap shear stress and to obtain a compromise between the reduced slot area and the improved temperature distribution. Experimental validation is then presented to compare the predicted results with the measured results on a purposely built instrumented setup.
KW - Electrical machine windings
KW - high current density
KW - permanent-magnet machines
KW - thermal improvements
UR - http://www.scopus.com/inward/record.url?scp=84856252212&partnerID=8YFLogxK
U2 - 10.1109/TIA.2011.2175470
DO - 10.1109/TIA.2011.2175470
M3 - Article
AN - SCOPUS:84856252212
SN - 0093-9994
VL - 48
SP - 79
EP - 87
JO - IEEE Transactions on Industry Applications
JF - IEEE Transactions on Industry Applications
IS - 1
M1 - 6074939
ER -