| 摘要 |
PROBLEM TO BE SOLVED: To realize the stabilized operation of a permanent magnet synchronous machine by limiting the load or output thereof to a specified range. SOLUTION: An effective current of a permanent magnet synchronous machine 2 is detected through a three-phase/two-phase converter 9, a coordinate converter 10 and the like, and the difference ▵ip between the detected value and an upper or lower limit value of effective current from a setter 13I is operated by an operating unit 14. Depending on the difference ▵ip , a frequency correction value ▵fi * is operated by an amplifier 15 having an integration element and a frequency command f* is corrected using the correction value. Subsequently, a voltage command V* substantially proportional to a corrected frequency command f* is operated by an f/V converter 4 and the synchronous machine 2 is subjected to drive control through a pulse width control circuit 7 and an inverter 1. |
