Patent ID: 8004226
Filing Date: 2011-08-23
Classification: H02P

Abstract:
1. A method of detecting a failed current sensor on an electric machine having a plurality of phases, comprising: measuring a phase current of each phase of the electric machine using a current sensor; calculating an open circuit threshold value based on at least one of the measured phase currents; determining if an absolute value of a sum of the phase currents of the electric machine is below the determined open circuit threshold value; identifying a failed current sensor by determining which of the phase currents is approximately zero, if the sum of the phase currents of the electric machine is not below the determined open circuit threshold value; and estimating the phase current for the failed current sensor by determining a phase current value for the failed current sensor that, when added to the phase currents of the remaining current sensors, makes the sum of all the phase currents equal to approximately zero.