| 摘要 |
PROBLEM TO BE SOLVED: To provide an initial-position detecting method, for a brushless DC motor, in which the stop position of an inner rotor can be detected without position sensor. SOLUTION: In this initial position detecting method for a brushless DC motor, a plurality of permanent magnets are arranged at an inner rotor which is arranged inside a stator via an air gap. The inductance characteristic of stator windings, with reference to the rotating position of the inner rotor, is measured in advance. A reference inductance value is prepared. When the inner rotor is stopped, vector voltages in three patterns are applied sequentially in a short time in the order of a stator winding U, a stator winding V and a stator winding W. Inductance values at the stop of the inner rotor of the stator windings in the respective patterns are measured. The inductance values at the stop of the inner rotor are compared with the reference inductance value, and the stop position of the inner rotor is detected. |
