Recognition of movement of polyphase unipolar stepping motor - is based on multiple samples of voltage taken from successive phases for comparison with desired value

摘要

A four-phase stepping motor (SM) is controlled by a microprocessor (muC) which evaluates the voltages of two successive phases (A,B) applied to it via respective voltage dividers (ST) and low-pass filters (SG). During two steps with positive voltage, ten samples are taken at regular intervals and stored in random-access memory. Interference spikes affecting one sample only are not interpreted as troughs, and no starting or stopping pulses are evaluated. USE/ADVANTAGE - In automotive electronics. Operation is insensitive to high-frequency interference arising from pulses generated when stepping motor attains its end stops.