| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a motor drive device that executes demagnetization protection with high accuracy, while executing high-efficiency drive and high-speed overload operation, when executing motor drive by switching between star connection and delta connection, and to provide a motor drive method and a refrigerating and air-conditioning device. <P>SOLUTION: An inverter control part 30 switches wire connection of a motor 11, by controlling wire-connection switching relays 21a-c, 22a-c that switch stator windings 15a-c of the motor 11 to either of star connection and delta connection on the basis of either of a frequency command and an external switching signal. A CPU 31 sets a motor constant matched with a wire-connection specification after switching and at least one of an overcurrent protection level and an abnormal voltage protection level, on the basis of an inverter output current and a DC bus-bar voltage that are detected by a current detection element 3. A PWM generating means 32 subjects an inverter main circuit 2 to PWM control, on the basis of the motor constant and the overcurrent protection level or the abnormal voltage protection level that are set by the CPU 31. <P>COPYRIGHT: (C)2008,JPO&INPIT |
