Patent ID: 9112439
Filing Date: 2015-08-18
Classification: G01R,G05B,H02P

Abstract:
1. Method for sensor-free detection of a motor load angle or load value in a stepper motor, comprising: generating from supplied target coil currents by a chopper process chopper switch signals, impressing, by a motor supply voltage which is switched by the chopper switch signals the target coil currents into motor coil terminals, generating, via the load angle and the load value, respectively, a counter-induced voltage in the motor coils, determining a temporal intersecting point of the courses of two motor voltages at two motor coil terminals, detecting a phase shift, caused by the counter-induced voltage, between one of these two motor voltages and the coil current at this motor coil terminal at the moment of the occurrence of the intersecting point, and determining the load angle and the load value, respectively, on the basis of the phase shift.