| 摘要 |
<P>PROBLEM TO BE SOLVED: To expand a drive region by improving stability in high load and high-speed drive of a brushless DC motor. <P>SOLUTION: A motor drive device includes: a brushless DC motor 4 comprising a rotor having a permanent magnet and a stator having a three-phase winding; and an inverter 3 for supplying power to the three-phase winding. In the motor drive device, the phase of a current flowing through the winding of the brushless DC motor is unfailingly acquired by selecting either a winding current or an output terminal voltage of the inverter 3 depending on the drive state of the brushless DC motor 4, the winding for energizing the brushless DC motor 4 is switched so that the current phase and voltage phase of the brushless DC motor 4 can keep a predetermined phase relation, and the predetermined phase relation kept between the current phase and voltage phase is changed depending on the amount of change of the peak of current flowing through the brushless DC motor 4 to expand the load region which can be driven by the brushless DC motor 4. Thus, even if any component is out of order, the motor can be driven while preventing step-out or overcurrent, thereby stably driving high load at a high speed. <P>COPYRIGHT: (C)2011,JPO&INPIT |
