Method and apparatus for synchronous driving of the phase windings of a DC motor

摘要

Synchronization of the phase switchings in driving a brushless motor with predefined excitation current profiles of substantially nonconstant value, is improved by continuously correcting the rotor position information detected by zero-cross detecting circuits with an updatable delay value. A switching delay counter is started by the raw zero-cross pulse to determine the generation of a corrected synchronization pulse. The delay counter is downloaded with a constantly updated value by monitoring the correction signal produced by a speed control loop and by incrementing or decrementing the downloaded value in the counter to minimize the correction signal.