In recent times there has been an increased interest expressed towards the use of advanced power-dense PM (permanent magnet) motors as an alternative to traditional excited synchronous machines in terms of marine power generation and utilisation. This relates specifically to AFM and
TFM (axial and transverse flux machines), since they potentially offer a higher torque per unit mass than more traditional technology. Consequently, much design work is being carried out to maximise the power to weight ratio of these machines although, in order to harness their full potential,
their control also needs to be optimised. This paper describes a generalised approach to electromagnetic torque control that utilises the motor's magnetic flux characteristic in order to ensure that maximum torque is produced for minimal input power. The method is generalised for any separately-excited
synchronous, permanent magnet or reluctance machine, including AFM and TFM. A TFM motor is used to illustrate the performance of this control algorithm and was chosen because of its highly non-linear nature.