On-board direct-drive surface permanent magnet synchronous machine with fractional-slot concentrated windings for electric vehicles

Removal of the gear-box from an existing electric vehicle (EV) power-train incorporating direct-drive topology is expected to improve motor-to-wheel efficiency. Firstly, this paper discusses the need for a novel direct-drive scheme employing a single on-board motor in an EV. Electric machine and drive design targets for such a supermini EV with direct-drive scheme are fixed based on analytical equations, benchmark data obtained from commercially available EV motors, drives, transmissions and literature study. Employing a comprehensive vehicle dynamics model of the supermini EV, machine design targets previously fixed are further refined to yield desired dynamic and steady-state performance of the EV over an urban drive cycle. An on-board direct-drive surface permanent magnet synchronous machine with fractional slot concentrated windings in the stator is designed. The machine's performance is then analyzed using its electromagnetic model in conjunction with maximum-torque-per-ampere control scheme over the entire speed range of the motor. Results from finite element analysis are discussed in detail to show that that the proposed direct-drive scheme in EV is worth studying and the machine designed can be improved in order to obtain efficiency improvement in an EV drivetrain system and hence extend the driving range of EV.

[1]  W. Fu,et al.  A dynamic core loss model for soft ferromagnetic and power ferrite materials in transient finite element analysis , 2004, IEEE Transactions on Magnetics.

[2]  R. Wrobel,et al.  Design Considerations of a Direct Drive Brushless Machine With Concentrated Windings , 2008, IEEE Transactions on Energy Conversion.

[3]  P. C. K. Luk,et al.  Torque Ripple Reduction of a Direct-Drive Permanent-Magnet Synchronous Machine by Material-Efficient Axial Pole Pairing , 2012, IEEE Transactions on Industrial Electronics.

[4]  Makoto Sato,et al.  Loss Analysis of Permanent-Magnet Motors With Concentrated Windings—Variation of Magnet Eddy-Current Loss Due to Stator and Rotor Shapes , 2008, IEEE Transactions on Industry Applications.

[5]  Thomas M. Jahns,et al.  Experimental verification of optimal flux weakening in surface PM machines using concentrated windings , 2005 .

[6]  Andreas Binder,et al.  Extended field weakening and overloading of high-torque density permanent magnet motors , 2009, 2009 IEEE Energy Conversion Congress and Exposition.

[7]  K. Shadan,et al.  Available online: , 2012 .

[8]  Fernando A. Silva Modern Electric, Hybrid Electric, and Fuel Cell Vehicles, Third Edition [Book News] , 2018, IEEE Industrial Electronics Magazine.

[9]  Narayan C. Kar,et al.  Investigation of Permanent-Magnet Motor Drives Incorporating Damper Bars for Electrified Vehicles , 2015, IEEE Transactions on Industrial Electronics.

[10]  T. M. Jahns,et al.  The expanding role of PM machines in direct-drive applications , 2011, 2011 International Conference on Electrical Machines and Systems.

[11]  W. Fei,et al.  A New Technique of Cogging Torque Suppression in Direct-Drive Permanent-Magnet Brushless Machines , 2010, IEEE Transactions on Industry Applications.

[12]  Narayan C. Kar,et al.  Rule-Based Control Strategy With Novel Parameters Optimization Using NSGA-II for Power-Split PHEV Operation Cost Minimization , 2014, IEEE Transactions on Vehicular Technology.