Modelling and simulation of a torus generator using PSPICE

The Torus machine consists of a toroidally-wound stator situated between two rotor discs on which are mounted permanent magnets. The axial length of this machine can be made small, for a given power rating, because the active conductor length is the radial length of the stator winding, which falls between the rotor magnets. This feature permits the design of axially compact generators which have found use in a variety of automotive applications. Existing machines have been modelled using a simple synchronous machine equivalent circuit. This simple model neglects the inter-winding mutual inductances which results in significant differences between measured and predicted operating performance. In this paper a more accurate model of the generator is presented, which was developed using PSPICE. Simulations of the generator are compared with measured results and are shown to exhibit a close correlation.