Patent ID: 7560895
Filing Date: 2009-07-14
Classification: G01R,H02P

Abstract:
1. An indirect rotor resistance estimation system for an AC induction motor comprising: a synchronous frame current regulator, responsive to direct and quadrature current commands and sensed fixed frame motor winding currents, for providing direct and quadrature voltages and converting them to fixed frame voltages, adjusted for the rotor flux angle, to drive the motor power stage; a control circuit for successively stepping said quadrature command to zero and said direct current command to a predetermined value causing the quadrature stator voltage to decay as a representation of rotor current decay; a storage device for storing at least one stator voltage decay time/voltage difference and corresponding reference rotor resistance; and a measurement circuit, responsive to the decaying stator voltage reaching spaced thresholds, for defining a voltage/time difference for retrieving from said storage device the associated rotor resistance.