| 摘要 |
PROBLEM TO BE SOLVED: To positively prevent a liquid refrigerant from staying in a compressor case by performing a positive correction to a frequency command at each specific time when the detection temperature of a refrigerant and a lubricant in the compressor is lower than a specific value when the operation frequency of the compressor is controlled according to a frequency command in response to an air-conditioning load. SOLUTION: The capacity of a compressor 2 is adjusted while the compressor 2 is driven at a variable speed by a compressor motor 9 consisting of an AC motor, and the AC motor 40 is driven under a frequency corresponding to the compressor rotation speed in response to the requested air-conditioning capacity at each time via a frequency converter 44 from an AC system power supply 42. In this case, a pseudo overheating control is performed and at the same time the output frequency of the frequency converter 44 is controlled according to a temperature deviation of ΔTA in an outdoor machine controller 48. However, at a region where an outdoor discharge pipe temperature TD is lower than a specific value, it is regarded that a frequency command Cf is too low and a positive correction is made where each specific frequency, for example, 2.5 Hz is added at each specific time for the frequency command Cf. |
