A measurement technique for direct axis and quadrature axis magnetic characteristics in a projected pole (stationary field type) synchronous machine

Abstract

The magnetic characteristics of a projected pole stationary field type synchronous machine are important in design and performance studies though they differ along direct axis (d-axis) and quadrature axis (q-axis). It is difficult to determine the q-axis magnetic characteristics, whereas the determination of d-axis magnetic characteristics can be done by performing an open-circuit characteristics test on the machine. In order to estimate both the d-q axes magnetic characteristics by a direct method, various flux measurement techniques such as the moving coil flux meter, ballistic galvanometer, magneto resistance flux meter, Hall effect flux meter and solid-state diode-flux meter have been analysed. A novel approach of using germanium diodes as flux sensors is proposed in this work to determine experimentally the d-q axes magnetic characteristics. The implementation of hardware, experimental investigations and the results are presented here. Furthermore, the merits and applications of the proposed method are also discussed.