BRUSHLESS DIRECT CURRENT MOTOR HAVING SFOC CONTROL

摘要

The invention relates to a control device (6) for a brushless direct current motor which determines target voltages (Ua, Ub, Uc) for phases thereof (U1, U2, U3) using a rotational position (alpha) of a rotor (2) of the direct current motor. The control device (6) accordingly controls an actuator (4) so that each phase (U1, U2, U3) is switched on to a supply voltage (VCC) within a respective timing cycle (T) during a total actuation time period (T1, T2, T3) corresponding with the respective target voltage (Ua, Ub, Uc). The control device (6) divides the timing cycles (T) into two directly successive, equally large partial cycles (T', T") and determines a respective partial activation period (T1', T1", T2', T2", T3', T3") for each phase (U1, U2, U3) for each partial cycle (T', T"). The control device (6) determines the partial activation time periods (T1', T1", T2', T2", T3', T3") so that they connect to each other, comprise the center of the respective partial cycle (T', T"), are symmetrical thereto and together are equal to the respective total actuation period (T1, T2, T3). The control device (6) calibrates the partial actuation time periods (T1', T1", T2', T2", T3', T3") to each other so that, in at least one permanently specified time interval (Z1', Z2') of the first partial cycle (T'), a current detection for one of the phases (U1, U2, U3) is possible and in at least one permanently specified time interval (Z1", Z2") of the second partial cycle (T"), a current detection for another of the phases (U1, U2, U3) is possible.