main purpose of the paper is to describe a small size hybrid vehicle having ultracapacitors as on-board storage unit. The vehicle on-board main power supply is achieved by a genset being formed of a 250 cm(3) internal combustion engine and a permanent magnet synchronous electric generator, whereas 4 16V-500F ultracapacitors modules are connected in series in order to supply as well as to store the power peaks during respectively acceleration and braking vehicle modes of operation. The traction power is provided by a permanent magnet synchronous electric motor, whereas a distributed power electronic interface is in charge of all the required electronic conversions as well of controlling the operating conditions for each power unit. The paper discusses the implemented control strategy and shows experimental results on the modes of operation of both generation unit and storage unit. (C) 2009 Elsevier B.V. All rights reserved.