ABSTRACT Electric scooters are suited to mobility in zones with environmental traffic limitations, and particularly for city centers with very poor room for parking. Aim of this paper is the illustration of the performance that can be obtained from a purposely designed electric scooter. The features of the main components of the scooter driveline: battery package, converter, motor and control will be described. INTRODUCTION Hybrid and Electrical Vehicles (HEV and EV, respectively) have become more and more usual in everyday life but still far, in terms of diffusion, from the forecasted values of the near future. Hybrid Vehicles are the solution where a significant autonomy is necessary, while nowadays EV are suited to urban range, with particular advantages if the daily run can be predicted or if it is periodical like public services, express couriers, limited traffic city centers, car and bike sharing, airport auxiliary services [ 1]. A typical example of such a vehicle is the electric urban scooter. A fundamental part of EVs and HEVs is the electrical driveline. A clear standard has not still been evidenced: in most of recent cases synchronous motor drives are adopted for their better efficiency and higher torque density. The asynchronous motor, often used for simplicity, has lower efficiency and larger weight, due to rotor losses. Where the mechanical gear box is avoided, in order to reduce the size of the power converter, it is convenient to choose an electric motor capable to provide constant power over a widespeed range (1:2, 1:4). Among synchronous motors, those able to suit such requirements are Interior Permanent Magnets (IPM) motors, provided they are are properly designed. About the power converter, the DC/AC inverter is preferably associated to a DC/DC stage for improving the electrical coupling with the battery and, more in general, with the on- board energy supply. A DC/DC converters on the DC link de- couples the DC/AC inverter and the motor from the battery voltage variation (due to load and state of charge drops), thus reducing the size of the DC/AC stage, as well as the reactive filter towards the battery. The on-board accumulator (typically batteries) still represents the most delicate point in terms of influence on the overall vehicle performance. The progress in this field has been continuous and promising. Of course, the commercial success of the HEV architecture has mainly pulled those technologies committed to high power-density (e.g. Ni-MH), rather than those for high energy-density (Li-based). Nevertheless, the most recent Li- ion and Li-polymers cells have very good energy levels, still in progress, and satisfactory power-density. There are many and stimulating opportunities of research and improvements in the field of electrical drives for traction. Such opportunities involve several of the aspects of the drive: the motor as well as the power converters, the power interface towards the batteries and the optimal management of the accumulator state: • The motor must be specifically designed for the application: the overload ratio and the constant power speed range have to be considered. The motor design must also minimize the iron loss at high speed, in order not to compromise the system efficiency at full speed. Actually there is not a design standard widely recognized. NEEXT : New Electric Experience For Traction2010-01-0034 Published 04/12/2010 Paolo Guglielmi, Paolo Macrì, Alfredo Vagati, Eric Armando and Gianmario Pellegrino Politecnico di Torino Copyright © 2010 SAE InternationalDownloaded from SAE International by Brought to you by the University of Texas Libraries, Sunday, August 05, 2018• The DC/DC conversion stage should be able to interface all the accumulators on-board, to have an optimal exploitation of any single source. Many solutions have been already proposed but still no clear comparison has been given. • The battery pack management must fully exploit all the cells, in charging