| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive improving efficiency, speed and torque. <P>SOLUTION: The motor drive is provided with a brushless DC motor 5 composed of a rotor having a permanent magnet and a stator having three phase winding, an inverter 3 supplying power to three phase winding, a first waveform generating part 15 outputting a rectangular wave whose conduction angle is 120 to 150 degrees or a waveform conforming thereto, a second waveform generating part 17 outputting the rectangular wave whose conduction angle is 130 to 180 degrees or a waveform conforming thereto, and a switching determination part 18 selecting output of the first waveform generating part 15 at a prescribed speed or lower and output of the second waveform generating part 17 at a speed higher than the prescribed speed. When a drive mode transition from the second waveform generating part 17 to the first waveform generating part 15, the conduction angle is set to be not more than 150 degrees. Thus, stable mode transition is achieved. <P>COPYRIGHT: (C)2009,JPO&INPIT |
