MEASURING DIFFERENTIAL INDUCTANCES OF ASYNCHRONOUS MACHINES

Asynchronous machines in traction applications are normally saturated during voltage-controlled operation. The saturation has an influence o n the differential inductances of the stator windings. The value of th ese differential inductances can be calculated based on a theory and m easured during a pulse period of the feeding voltage-source inverter ( VSI). This paper concentrates on the measurement of differential induc tances and contains only a short recapitulation of the theory. Measure d values of differential inductances might be used to estimate the sta tor-flux space vector of the asynchronous machine without speed measur ement even at stator frequency zero as a basis for high-performance to rque control without speed measurement.