Prediction of starting performance of PM motor by DC decay testing method

This paper presents a method to predict the direct- and quadrature-axis operational impedances and starting performance of PM motors by a simple standstill response testing method using a small-capacity DC power supply unit. In this method, not only the starting performance but also the direct- and quadrature-axis synchronous machine constants (synchronous, transient and subtransient reactances) and equivalent circuit constants are calculated. This proposed strategy, tentatively named the DC decay testing method, is carried out on a 3.7 kW 200 V 22 A 100 Hz four-pole interior PM motor with a damper winding. The results measured by on-load tests and those predicted by the proposed method on starting performance demonstrate the validity and usefulness of the proposed method.