Flywheel peak power buffer for electric/hybrid vehicles

Kinetic energy storage systems have considerable potential for use as peak power buffers in drive-trains for electric and hybrid vehicles, as a means of enhancing their performance and improving efficiency. The paper describes a flywheel system based around a cylindrical fibre composite rim, which is supported on magnetic bearings and incorporates an integral motor/generator. Particular consideration is given to minimising power losses, by appropriate choice of magnetic circuit design and magnetic materials, so as to obtain a high 'round-trip' efficiency and limit the temperature rise of the rim.