| 摘要 |
The invention relates to a method for starting a brushless d.c. motor comprising a multi-phase stator winding. According to the invention, a plurality of current pulses is applied to the stator winding while the rotor is stationary, a current build-up period is measured in the stator winding for each current pulse until a current threshold has been reached and the rotor position is derived from the current build-up periods that have been measured. The aim of the invention is to obtain a controlled acceleration without the use of a sensor and to precisely determine the rotor position without using complex control technology. To achieve this, a plurality of test current pulses is successively applied to the stator winding in such a way that the test current pulses in the stator generate stator flow vectors across 360 DEG , which are electrically offset by identical angular increments. The current build-up period is measured in the aggregate current of the stator winding for each stator flow vector and the phase angle of the stator flow vector with the shortest current build-up period is determined as the rotor position. |
