Patent ID: 8975845
Filing Date: 2015-03-10
Classification: H02P

Abstract:
1. A method of detecting a failure of a permanent magnet motor system comprising: monitoring a current of each phase of the permanent magnet motor system; repeatedly comparing a value indicative of power of the permanent magnet motor system to a threshold value indicative of power for a low power detection period; indicating a first error condition when the value indicative of power remains below the threshold value indicative of power for an entire low power detection period; estimating a current error; monitoring a speed of the permanent magnet motor system based in part on the current error; repeatedly comparing the speed of the permanent magnet motor system to a speed threshold for a speed failure detection period; indicating a second error condition when the speed of the permanent magnet motor system remains below the speed threshold for an entire speed failure detection period; repeatedly comparing the current of each phase of the permanent magnet motor system to a phase current threshold for a loss of phase detection period; and indicating a third error condition when the current of at least one phase of the permanent magnet motor system remains below the phase current threshold for an entire loss of phase detection period.