| 摘要 |
PROBLEM TO BE SOLVED: To eliminate deterioration in the efficiency of a brushless motor. SOLUTION: This sensorless drive and control apparatus controls a brushless motor, having three stator windings 102u, 102v, 102w and a permanent magnet rotor 103 which is rotated and driven by magnetic field. Here this apparatus is provided with commutation element 104-109, which change over the drive current caused to flow in the stator windings 102u, 102v, 102w by switching and a zero-cross point detecting part 122, which detects the zero-cross point of the potential difference between the terminal voltages of the stator winding 102u, 102v, 102w for each phase and neutral potential. The zero-cross point of a surge voltage is removed from the detected zero-cross point for each phase, so that only the zero-cross point of an induced voltage in the section to be changed by the induced voltage of each phase is extracted. Then, the commutator elements 104-109 are caused to perform switching with delay by a time interval corresponding to a specified electric angle obtained from the extracted zero-cross point of the induced voltage. |
