Impact of Saturation on Transient Behavior of Interior Permanent Magnet Synchronous Motors

Interior permanent magnet synchronous machines have larger ferromagnetic path along the quadrature axis and as a result, the q-axis magnetizing reactance saturates significantly under normal operating conditions. Although, the effective air-gap path length along the direct axis is large, the d-axis magnetizing reactance also saturates up to a certain extent. But in the two-axis (d- and q-axis) frame transient analysis of these machines, usually the impact of the saturation, especially the effect of the d-axis saturation is ignored. So, the aim of this paper is to demonstrate the importance of inclusion both d-and q-axis saturation on the transient behavior of permanent magnet synchronous motors in the case of a bolted three-phase symmetrical short circuit fault