A generalised approach to torque ripple compensation in permanent magnet machine control

The traditional approach to permanent magnet machine control is based on the distinction between DC and AC machines. The main difference is that in DC machines, the FEM has a trapezoidal shape, while in the AC machines it has a sinusoidal shape. In the first case, typically a scalar two phase approach is applied, while in the second one a vector three phase approach is the typical structure. In a recent paper, the authors showed that for special purpose machines, it is not so easy to make this kind of distinction, both from modeling and control point of view. Starting from that, a unified approach to the control of isotropic permanent magnet machines is proposed, keeping the minimum of the torque ripple as main task. The algorithm is described in detail and the results are confirmed through experimental experiences