Patent ID: 9476626
Filing Date: 2016-10-25
CPC Classification: F25B,H02P,Y02B

Claim Text:
1. A drive controller for a motor of a compressor, the drive controller comprising: a drive circuit that applies voltages to windings of the motor; a speed control module that controls the drive circuit to rotate the motor at a requested speed; a speed determination module that generates the requested speed based on a speed demand from a system controller; and a lost rotor control module that identifies a lost rotor condition and, in response to identifying the lost rotor condition, instructs the speed determination module to set the requested speed to an override speed that is lower than the speed demand, wherein: the lost rotor control module identifies the lost rotor condition in response to a comparison of a speed error with an adaptive threshold, the speed error is based on a difference between the requested speed and an estimated speed of the motor, during a first system state, the adaptive threshold is equal to a first threshold, and during a second system state, the adaptive threshold is equal to a second threshold.