| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently and stably operate a synchronous motor connected to a load where torque periodically and largely fluctuates in accordance with a machine angle such as a compressor with low operation load by a simple structure. <P>SOLUTION: A phase difference detecting part 8 detects a phase difference between drive voltage and wiring current in the synchronous motor 1. A PI operating part 11 calculates a duty reference value Rd of a PWM signal by comparison of a detection value and a target phase difference. An AC wave data generating part 14 judges the machine angle of the synchronous motor 1 based on an electrical angle. The AC wave data generating part 14 and a PWM generating part 15 generate a PWM signal Sp for 180 degrees conduction driving, which is supplied to an inverter circuit 2 based on a correction sine wave data table TB1 showing an AC signal on which a fluctuation component of load torque of the synchronous motor 1 is reflected, on the duty reference value Rd and a judging result of the machine angle. <P>COPYRIGHT: (C)2009,JPO&INPIT |
