| 摘要 |
There is provided a centrifugal compressor apparatus including a centrifugal compressor 12 that centrifugally compresses a gas 1, an electric motor 14 that rotatably drives the centrifugal compressor, a current detector 16 that detects a drive current I of the electric motor, and an exhaust valve 18 that discharges a compressed gas 2 to a lower pressure section 3. The centrifugal compressor apparatus (A) detects the drive current I at a sampling cycle ts, (B) updates, as a current threshold, in real time, a value "(moving average) - n x (standard deviation)" for which a plurality of drive currents measured in a sampling period tp serves as a population, where n is a positive number in the range of 3 to 4 and, (C) determines that surging has occurred when the exhaust valve 18 is closed and the drive current I is below the current threshold X, and (D) further opens the exhaust valve 18 to discharge the compressed gas 2 when determining that surging has occurred. |
