Method for controlling sensorless, brushless direct current (DC) electromotor used as actuator for air valve or in motor vehicle, involves dividing every commutation interval into driving and braking phases in braking operation

摘要

The method involves actuating brushless DC motor (3) via a bridge circuit (9), by pulse width modulation (PWM) with pre-commutation. Every commutation interval is divided into driving phase and braking phase in braking operation, such that a driving phase extends upto a zero crossing voltage from the beginning of commutation interval, during which motor is driven with the normal pulse width modulation (PWM), and a braking phase which extends from zero crossing voltage to next commutation point of time. An independent claim is included for brushless DC electromotor.