| 摘要 |
PURPOSE:To provide a method and a circuit for detecting the rotor position of a brushless motor in which the cost is reduced by reducing the scale of the detecting circuit. CONSTITUTION:When a three-phase brushless motor is subjected to rotational control by sequentially exciting the specific phase of the stator windings, the rotor position is detected based on the terminal voltage of the stator winding. One U of a plurality of terminal voltages U, V, W of the stator winding is converted, by a level converting circuit 10, into a signal level of a microcomputor and fed to a control section 11. The control section (microcomputor) 11 detects the signal waveform of the level converted voltage at an A/D converting section 12 and a position detecting section 13 obtains signals of 120 deg. and 240 deg. phase lag from the detected signal. A rotor position detection signal is then determined based on the signal thus obtained and the level converted signal. |
