Study of the Induction Motor with Arbitrary Stator Winding In Wye-Connection

The anisotropy of a cage rotor is utilized to determine the angular position of the rotor in an induction machine. The switching transients generated by a pulsewidth controlled inverter serve as test signals. The response of the three inverter terminal currents is exploited to derive a quasi-instantaneous rotor position signal. The position is sensed at the inverter through the 3-phase motor cable by measuring the current derivatives. The method is applicable to induction motors having the stator windings connected either in wye or in delta.