| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of performing position detection of a permanent-magnet motor without using a position sensor or a special position detection signal when the permanent-magnet motor is in a stop state or in a very low-speed state. <P>SOLUTION: A drive system for a permanent magnet motor is composed of a mode switching trigger generator 8, which monitors a state of a permanent-magnet motor 4 and issues a mode switching trigger, a conduction mode determinator 6 for performing mode switching of the permanent-magnet motor 4 by receiving the mode switching trigger, and a PWM generator 5 that outputs a PWM signal to an inverter 3 according to output of the conduction mode determinator 6. The mode switching trigger is generated on the condition that a speed electromotive force of the permanent-magnet motor 4 exceeds a fixed or variable threshold. <P>COPYRIGHT: (C)2009,JPO&INPIT |
