Magnetic cross-coupling effects on the performance of the synchronous reluctance machine

Performance prediction and control of a synchronous reluctance machine is based on the knowledge of the direct and the quadrature axis inductances. The properties of the machine depend on the saliency ratio of these inductances and this is implemented by introducing internal flux barriers. In an idealized linear magnetic topology the superposition principle would allow to derive both properties separately by exiting a single axis. However, in a real case with saturation effects a cross coupling of the axes appears, which alters the resulting values. Both methods are adopted in the numerical simulation and in practical measurements. By comparing the inductance values, the effects of saturation and coupling can be observed and interpreted. The ideal current trajectories in the operation regions or the resulting curves for a variable speed operation alter when different properties of the machine are assumed. The comparison to practical measurements show a certain match of the simplified methods. However, the cross coupling are more pronounced in regions with low currents and therefore the differences increase in the low flux areas at high speed.