Electronically commutated direct current machine sensor-less operation method for e.g. automobile area, involves predetermining time point of zero crossing of voltage and calculating interval according to time point of last zero-crossing

摘要

The method involves determining zero crossings of a voltage induced by a rotating field of a rotor in a non-powered phase. The time point of next zero crossing of the voltage is predetermined by using a control device (16), and a time interval is calculated according to the predetermined time point of the last detected zero-crossing. A sampling rate of the voltage is adjusted according to an actual step time that is calculated from the time difference between the determined zero crossing and last determined zero crossing of the voltage. An independent claim is also included for an electrical drive comprising an electronically commutated direct current machine.