Performance of toroidal stator, axial flux brushless DC motor under dynamic conditions of operation

The machine under investigation has been described in earlier publications and under the name TORUS (1990, 1991). It is a class of brushless dc motor which uses the standard bridge arrangements of a six-MOSFET power controller. The machine itself is of a rather unusual simple construction. It comprises a stator which has a toroidal and slotless core sandwiched by a two-disc rotor. Each disc carries an axially polarized neodymium-iron-boron magnets. Four dynamic modes of operation are considered in this paper. These are, the motor start-up, voltage variation, failure of one of the switching devices of the controller and when the motor is used to crank an engine. The actual dynamic equations of the drive have been used and solved using a simple simulation software package especially developed for this type of drive