Brushless direct current motor having sfoc control

Abstract

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.

Description

technical field [0001] The invention relates to a control method for a brushless direct current motor, [0002] - in which the control device for a direct current motor obtains the rated voltage for the phases of the direct current motor using the rotational position of the rotor of the direct current motor, [0003] - wherein the control device actuates the regulating device as a function of the ascertained nominal voltage for the phases, so that each phase is switched on to the supply voltage during a total on-time period corresponding to the respective nominal voltage within the respective clock cycle superior, [0004] - wherein the control device divides the clock cycle into two directly successive sub-periods of the same size and ascertains for each sub-period a corresponding on-time sub-period for each phase, [0005] - wherein the control device determines for each phase a sub-on-time period such that the sub-on-time period is symmetrical to the center of the corresp...

AI Technical Summary

Problems solved by technology

[0024] Although the behavior of EP 2 120 323 B1 leads to technically satisfactory results in regulation, it is technically expensive to implement

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