Title: Sources of power loss during torque-vectoring for fully electric vehicles

Authors: Andrew Pennycott; Leonardo De Novellis; Patrick Gruber; Aldo Sorniotti

Addresses: Department of Mechanical Engineering Sciences, University of Surrey, Guildford, GU2 7XH, UK ' Department of Mechanical Engineering Sciences, University of Surrey, Guildford, GU2 7XH, UK ' Department of Mechanical Engineering Sciences, University of Surrey, Guildford, GU2 7XH, UK ' Department of Mechanical Engineering Sciences, University of Surrey, Guildford, GU2 7XH, UK

Abstract: Continuous wheel torque control of fully electric vehicles (FEV) offers potential improvements in vehicle dynamics and energy efficiency. Various studies have shown benefits from torque-vectoring for minimising vehicle power consumption by considering the losses from the electric motor drives. However, during vehicle operation, various sources of power loss exist such as dissipations due to longitudinal and lateral tyre slip which are strongly influenced by the wheel torque control system. In this study, the different power loss types during steady-state and transient manoeuvres of a case study four-wheel-drive FEV are quantified. The motor drive losses are a major contributor at low lateral acceleration but represent a secondary factor at significant lateral acceleration at which the tyre slip power losses are the most significant contribution. Future control allocation methods seeking to reduce power consumption should consider tyre slip in addition to actuator losses.

Keywords: electric vehicles; control allocation; vehicle dynamics; energy efficiency; power loss; torque vectoring; continuous wheel torque control; electric motor drives; tyre slip; four wheel drive; actuator losses; vehicle design.

DOI: 10.1504/IJVD.2015.068142

International Journal of Vehicle Design, 2015 Vol.67 No.2, pp.157 - 177

Available online: 15 Mar 2015 *

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