Final Report on Control Algorithm to Improve the PartialLoad Efficiency of Surface PM Machines with FractionalSlot Concentrated Windings
Abstract
Surface permanent magnet (SPM) synchronous machines using fractionalslot concentrated windings are being investigated as candidates for highperformance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constantpower speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque amplitudes as well as significantly increasing the machine power density [35] compared to SPM machines using conventional distributed windings. High efficiency can be achieved in this class of SPM machine by making special efforts to suppress the eddycurrent losses in the magnets [68], accompanied by efforts to minimize the iron losses in the rotor and stator cores. Considerable attention has traditionally been devoted to maximizing the fullload efficiency of traction machines at their rated operating points and along their maximumpower vs. speed envelopes for higher speeds [9,10]. For example, online control approaches have been presented for maximizing the fullload efficiency of PM synchronous machines, including the use of negative daxis stator current to reduce the core losses [11,12]. However, another important performance specification for electric traction applications is the machine's efficiency at partial loads. Partialload efficiency is particularly important ifmore »
 Authors:

 ORNL
 University of Wisconsin
 Publication Date:
 Research Org.:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Power Electronics and Electric Machinery Research Facility
 Sponsoring Org.:
 USDOE Office of Energy Efficiency and Renewable Energy (EERE)
 OSTI Identifier:
 931549
 Report Number(s):
 ORNL/TM2007/048
VT0302000; CEVT022; TRN: US200813%%416
 DOE Contract Number:
 DEAC0500OR22725
 Resource Type:
 Technical Report
 Country of Publication:
 United States
 Language:
 English
 Subject:
 33 ADVANCED PROPULSION SYSTEMS; ALGORITHMS; AMPLITUDES; DESIGN; EFFICIENCY; IRON; MAGNETS; PERFORMANCE; PERMANENT MAGNETS; POWER DENSITY; PROPULSION SYSTEMS; ROTORS; SPECIFICATIONS; STATORS; TARGETS; TORQUE; VECTORS; VELOCITY
Citation Formats
McKeever, John W, Reddy, Patel, and Jahns, Thomas M. Final Report on Control Algorithm to Improve the PartialLoad Efficiency of Surface PM Machines with FractionalSlot Concentrated Windings. United States: N. p., 2007.
Web. doi:10.2172/931549.
McKeever, John W, Reddy, Patel, & Jahns, Thomas M. Final Report on Control Algorithm to Improve the PartialLoad Efficiency of Surface PM Machines with FractionalSlot Concentrated Windings. United States. doi:10.2172/931549.
McKeever, John W, Reddy, Patel, and Jahns, Thomas M. Tue .
"Final Report on Control Algorithm to Improve the PartialLoad Efficiency of Surface PM Machines with FractionalSlot Concentrated Windings". United States. doi:10.2172/931549. https://www.osti.gov/servlets/purl/931549.
@article{osti_931549,
title = {Final Report on Control Algorithm to Improve the PartialLoad Efficiency of Surface PM Machines with FractionalSlot Concentrated Windings},
author = {McKeever, John W and Reddy, Patel and Jahns, Thomas M},
abstractNote = {Surface permanent magnet (SPM) synchronous machines using fractionalslot concentrated windings are being investigated as candidates for highperformance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constantpower speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque amplitudes as well as significantly increasing the machine power density [35] compared to SPM machines using conventional distributed windings. High efficiency can be achieved in this class of SPM machine by making special efforts to suppress the eddycurrent losses in the magnets [68], accompanied by efforts to minimize the iron losses in the rotor and stator cores. Considerable attention has traditionally been devoted to maximizing the fullload efficiency of traction machines at their rated operating points and along their maximumpower vs. speed envelopes for higher speeds [9,10]. For example, online control approaches have been presented for maximizing the fullload efficiency of PM synchronous machines, including the use of negative daxis stator current to reduce the core losses [11,12]. However, another important performance specification for electric traction applications is the machine's efficiency at partial loads. Partialload efficiency is particularly important if the target traction application requires long periods of cruising operation at light loads that are significantly lower than the maximum drive capabilities. While the design of the machine itself is clearly important, investigation has shown that this is a case where the choice of the control algorithm plays a critical role in determining the maximum partialload efficiency that the machine actually achieves in the traction drive system. There is no evidence that this important topic has been addressed for this type of SPM machine by any other authors. This topic takes on even greater significance for fractionalslot concentratedwinding SPM machine designs. In particular, maximizing the torque/power density of this class of SPM machines typically leads to machine designs with high numbers of poles. The resulting high electrical frequencies can easily result in high stator core losses unless special care is taken during the machine design process. The purpose of this report is to discuss a modified vector control algorithm for a fractionalslot concentrated winding SPM machine that has been developed to maximize the machine's partialload efficiency over a wide range of operating conditions. For purposes of this discussion, a 55 kW (peak) SPM machine designed to meet requirements established in the US FreedomCar program [13] is used as the basis for demonstrating the proposed technique. A combination of closedform analysis [14] and finite element analysis (FEA) is used during this investigation.},
doi = {10.2172/931549},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2007},
month = {5}
}