Foresight Vehicle: A Toroidal, Axial Flux Generator for Hybrid IC Engine/Battery Electric Vehicle Applications

This paper describes the design, development and construction of axial flux, permanent magnet, toroidal generators for use with an IC engine in the auxiliary power unit (APU) of a series hybrid electric vehicle. Generators in the power range of 15 - 60 kW are described. The toroidal generator is very short and can be mounted directly on the engine output shaft in place of the engine flywheel. This eliminates the need for separate bearings and couplings and produces a very compact generating unit. The generator can also be used as a brushless motor for engine starting. Measured efficiency values for a prototype 40kW unit are provided and demonstrate efficiencies in excess of 90% across the entire speed range.