Patent ID: 9013133
Filing Date: 2015-04-21
Classification: H02P

Abstract:
1. A method for detecting a condition of a stepper motor, comprising the steps of: providing a stop for stalling the stepper motor; micro-stepping the stepper motor in a first direction toward the stop for a predetermined number of micro-steps; simultaneously micro-stepping the stepper motor in the first direction toward the stop for at least one additional micro-step to compress the stepper motor against the stop and sampling the back electro-motive-force (EMF) of the stepper motor; integrating the back EMF samples; comparing the integrated back EMF samples to a predetermined threshold to determine whether the stepper motor is in a stall condition; and in response to the integrated back EMF samples being under the predetermined threshold, micro-stepping the stepper motor to a micro-Rotor Offset Value (μROV), and in response to the integrated back EMF samples being greater than the predetermined threshold, stepping the stepper in the first direction and iteratively re-preforming the integrating and the comparing, wherein the steps are performed in response to a vehicle starting.