| 摘要 |
PROBLEM TO BE SOLVED: To achieve power saving by utilization of regenerative power when rotational speed variation of a motor is suppressed in association with a periodical load.SOLUTION: DC power supply is obtained by supplying an AC power supply 1 to a converter 2, is smoothed by a smoothing capacitor 3, is converted to AC power supply by an inverter 4, and is supplied to a motor 5. The motor 5 drives a compressor 6 which shows periodical load variation. A regenerative resistance 7 is connected between output terminals of the converter 2. When regenerative operation is partially conducted in order to reduce rotational speed variation in association with the periodical load variation, a flow of power in one rotation average is in a direction from the inverter 4 to the motor 5, and DC voltage does not continue to rise due to regeneration. Thereby, inverter operation can be continued without energy consumption by the regenerative resistance 7 by properly selecting capacity of the smoothing capacitor 3. |
