Compressed air production facility, compressed air pressure setpoint adjusting method, and compressed air pressure setpoint adjusting program

A compressed air pressure setpoint adjusting method executed by a compressed air production facility for supplying compressed air to compressed air consuming devices connected to a compressed air distributions line, the compressed air production facility including a plurality of air compressors connected to the compressed air distributions line via respective air tanks,

• each of the air compressors including
• a compressor that compresses air,
• an adjusting unit that adjusts a pressure setpoint of an air tank to which the air compressor comprising the adjusting unit is connected, and
• a control unit that operates a rotational frequency of the compressor on the basis of the pressure setpoint adjusted by the adjusting unit and a pressure of the air tank, the method comprising:
• by the adjusting unit, adjusting the pressure setpoint on a basis of a control variable indicating rotational frequency of the compressor or the pressure of the air tank,
• by the control unit, stopping rotation of the compressor by reducing the rotational frequency or setting the rotational frequency to zero in a case in which the pressure of the air tank exceeds the pressure setpoint, and keeping the air tank at the pressure setpoint by increasing the control variable of the compressor in a case in which the pressure of the air tank is below the pressure setpoint,
• the control units in the plurality of air compressors are not centralized control units but distributed control units and autonomously control each air compressor without communication between the control units and realize operation and stop of the air compressors in response to an increase or decrease in demand for the compressed air,
• the adjusting unit of each of the air compressors adjusts the pressure setpoint of the air tank independently of each other, and
• the adjusting unit determines whether a value of the control variable is greater than or equal to zero, and in a case in which the control variable is less than zero the adjusting unit increases the pressure setpoint of the air tank from a predetermined pressure stepwise by a pressure setpoint update width until the control variable is greater than or equal to zero, at which time the adjusting unit performs an additional adjustment of the pressure setpoint, in which the pressure setpoint is set equal to
• SV
• -
• (
• fnow
• ❘
• "\[LeftBracketingBar]"
• fbef
• ❘
• "\[RightBracketingBar]"
• +
• fnow
• )
• ×
• Δ
• ⁢
• SV
• ,
• wherein fnow is a latest value of the control variable, fbef is a previous value of the control variable, and ΔSV is the pressure setpoint update width.

A non-transitory computer-readable medium storing a compressed air pressure setpoint adjusting program for a computer, which when executed causes the computer to execute a method comprising:

• functioning as an adjusting unit that is connected to each of a plurality of air compressors and that adjusts a pressure setpoint in a compressed air production facility for supplying compressed air to compressed air consuming devices connected to a compressed air distributions line, the compressed air production facility including the plurality of air compressors connected to the compressed air distributions line via respective air tanks, each of the air compressors including a compressor that compresses air, and a control unit that operates a rotational frequency of the compressor on a basis of a pressure setpoint of an air tank to which each of the air compressors is connected and a pressure of the air tank,
• by the adjusting unit, adjusting the pressure setpoint on the basis of a control variable indicating the rotational frequency of the compressor or the pressure of the air tank, and
• by the control unit, stopping rotation of the compressor by reducing the rotational frequency or setting the rotational frequency to zero in a case in which the pressure of the air tank exceeds the pressure setpoint, and keeping the air tank at the pressure setpoint by increasing the control variable of the compressor in a case in which the pressure of the air tank is below the pressure setpoint,
• the control units in the plurality of air compressors are not centralized control units but distributed control units and autonomously control each air compressor without communication between the control units and realize operation and stop of the air compressors in response to an increase or decrease in demand for the compressed air,
• the adjusting unit of each of the air compressors adjusts the pressure setpoint of the air tank independently of each other, and
• the adjusting unit determines whether a value of the control variable is greater than or equal to zero, and in a case in which the control variable is less than zero the adjusting unit increases the pressure setpoint of the air tank from a predetermined pressure stepwise by a pressure setpoint update width until the control variable is greater than or equal to zero, at which time the adjusting unit performs an additional adjustment of the pressure setpoint, in which the pressure setpoint is set equal to
• SV
• -
• (
• fnow
• ❘
• "\[LeftBracketingBar]"
• fbef
• ❘
• "\[RightBracketingBar]"
• +
• fnow
• )
• ×
• Δ
• ⁢
• SV
• ,
• wherein fnow is a latest value of the control variable, fbef is a previous value of the control variable, and ΔSV is the pressure setpoint update width.