METHOD AND CIRCUIT ARRANGEMENT FOR SENSORLESS MOTOR LOAD DETECTION AND FOR CONTROLLING THE MOTOR CURRENT IN ACCORDANCE WITH THE LOAD VALUE IN STEPPER MOTORS

摘要

The invention relates to a method and a circuit arrangement which enable a mechanical load applied to the motor shaft of a stepper motor (M) or a load angle of said stepper motor to be detected in a sensorless manner. The invention also relates to a method and circuit arrangement which enable the motor current(s) of a stepper motor to be controlled in accordance with the load value such that the load angle is as high as possible without risking step losses, in order to maintain the current consumption of the motor as low as possible. This is achieved according to the invention, essentially by evaluating the temporal duration of the ON- and the FD-phases during the chopper control of the motor.