1154IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 49, NO. 5, OCTOBER 2002A High-Torque Low-Speed Multiphase BrushlessMachine—A Perspective Applicationfor Electric VehiclesMarcelo Godoy Simões, Senior Member, IEEE,and Petronio Vieira, Jr., Associate Member, IEEEAbstract—This paper presents the design, analysis, simulation,and modeling of a high-torque low-speed multiphase permanent-magnet brushless machine. The machine fits an in-wheel motor ar-rangement to be used for electric vehicle applications. This paperpresents issues regarding the high-level modeling comprised of atransient model in conjunction with their corresponding experi-mental evaluation. Analysis was made to combine the modelingefforts with the expected behavior concerned with mutual induc-tance and armature reaction effects, so as to have realistic simu-lation results verified by the experimental setup. Comprehensiveexperimental results corroborate the work.Index Terms—Brushless machines, digital signal processors,electric machines, modeling, motor drives.I. INTRODUCTIONELECTRIC vehicle (EV) propulsion systems have beinghistorically driven by two distinct threads, because thereare basically two ways to achieve high power density and high-efficiency drives. The first way is to employ high-speed motors,so that motor volume and weight will then be greatly reducedat the same rated output power. However, mechanical losses areincurred by the clutch, reduction, and differential gear duringpower transmission from the motor to the wheels. Increasingthe motor speed may reduce the size and weight of the electricmotor, but the corresponding values for the mechanical gearboxare likely to grow. The second thread for propulsion is to em-ploy high-torque low-speed motors, which can directly drive thewheels ,  . One standard solution is to connect a machineoutside the hub so as to avoid unsprung mass effects on the sus-pension system. A high-torque low-speed in-wheel motor maybe implemented in several topologies, but permanent-magnetbrushless (PMB) machines are preferable due to the higher ef-ficiency.This paper describes the design of a PMB direct-driven wheelmotor drive system comprising a multiphase multipole topologycontroller. It presents the high-level modeling, where a generaldynamic model for a multiphase PMB, in conjunction with thecorresponding inverter, is used to simulate the system. Exper-imentation and static evaluation were sought to fully comple-ment the equation parameters.Manuscript received December 14, 2000; revised May 9, 2002. Abstract pub-lished on the Internet July 15, 2002.M. G. Simões is with the Engineering Division, Colorado School of Mines,Golden, CO 80401-1887 USA.P. Vieira, Jr., is with the the Computer and Electrical Engineering Department,Universidade Federal do Pará, 66075-900 Belém, Brazil.Publisher Item Identifier 10.1109/TIE.2002.803241.