JP5484867B2 - Compressed air supply system and method - Google Patents

Description

  The present invention relates to a control technique for an air compressor, and more particularly, to an air compressor operation control technique for controlling the number of operating air compressors that send compressed air to an air tank based on the state of compressed air sent from the air tank to a load. .

A compressed air supply system that supplies compressed air to loads such as various utility facilities and building facilities in a factory is provided with a plurality of air compressors that generate compressed air, and the compressed air delivered from these air compressors Is temporarily stored in the air tank and then sent out from the air tank to the load.
This compressed air supply system is provided with a function for switching and controlling the operation of each air compressor in accordance with load fluctuations for the purpose of reducing operating costs and reducing environmental loads represented by CO2 emissions. (For example, see Patent Document 1).

  Conventionally, in such a compressed air supply system, a technology for rotating the operation of each air compressor has been proposed so that the accumulated operation time of each air compressor is leveled in consideration of the life of the air compressor. (For example, see Patent Document 2). Moreover, when loading / unloading each air compressor according to the fluctuation | variation of load, the technique of loading / unloading each air compressor one by one based on the preset selection order is proposed ( For example, see Patent Document 3).

Japanese Patent No. 4112869 JP 2006-275458 A Japanese Patent No. 3437763

  However, all of these conventional techniques are intended to extend the life of the equipment by leveling the operating time of these air compressors on the premise that a plurality of air compressors having the same efficiency are used. is there. Therefore, when air compressors having different efficiency, capacity, and control method coexist, there is a problem that it is difficult to easily extend the life of the apparatus, reduce the operating cost, and reduce the environmental load.

  The present invention is for solving such problems, and even when air compressors having different efficiency, capacity, and control method are mixed, air compression capable of realizing appropriate operation utilizing the characteristics of each air compressor. It aims to provide machine operation control technology.

In order to achieve such an object, a compressed air supply system according to the present invention collects compressed air generated by a plurality of air compressors that generate compressed air and supplies them to a load. The air compressor includes an air compressor control device that adjusts the air pressure by switching and controlling the operating state of the air compressor according to a change in air pressure indicating the pressure of the compressed air measured by the supply unit. A storage unit that stores operation setting data in which a priority order to be selected for switching control for each air compressor is preset in the machine control device, and an air compressor based on the priority order of the operation setting data Select an air compressor that is subject to switching control, and select the operating state of the selected air compressor as a load state that discharges compressed air or an unloaded state that does not discharge compressed air according to changes in air pressure. Look including a switching control unit for switching control to the switching control unit, when selecting the air compressor for any priority, if the air compressor with the priorities there are a plurality of these air compressor These air compressors are sequentially rotated and selected based on the frequency of use .

  At this time, the switching control unit may finely adjust the air pressure by outputting a rotation speed command corresponding to a change in air pressure to the inverter-controlled air compressor of the air compressor.

  Further, the storage unit stores a plurality of operation setting data having different priorities set for each air compressor, and the switching control unit selects any of the operation setting data selected from the operation setting data according to a preset operation schedule. You may make it select the air compressor used as the object of switching control based on the priority of one operation setting data.

  Further, the switching control unit selects an air compressor to be switched to the load state or the unload state by the next switching control from the air compressors based on the priority order of the operation setting data, and the selection result is assigned to each air compressor. You may make it output as control status data which shows the control status with respect to a compressor.

The compressed air supply method according to the present invention includes a step in which a plurality of air compressors generate compressed air, a step in which a supply unit collects compressed air generated by the air compressor and supplies the compressed air to a load, The air compressor control device includes an air compressor control step for adjusting the air pressure by switching and controlling the operating state of the air compressor according to a change in air pressure indicating the pressure of the compressed air measured by the supply unit. In the air compressor control step, the switching control target is selected from the air compressors based on the priority order selected as the switching control target, which is preset for each air compressor in the operation setting data of the storage unit. The selection step of selecting the air compressor to be selected and the operation state of the selected air compressor according to the change in the air pressure, the load state that discharges compressed air or the unloading that does not discharge compressed air Look including a switching control step for switching control to the state, the switching control step, when selecting the air compressor for any priority, if the air compressor with the priorities there are multiple, they air compressor These air compressors are sequentially rotated and selected based on the frequency of use .

  According to the present invention, the load priority order and unload priority order of the operation setting data can be arbitrarily set based on the efficiency, capacity, and control method of each air compressor. For this reason, even when air compressors having different efficiency, capacity, and control method coexist, it is possible to realize appropriate operation utilizing the characteristics of each air compressor. Therefore, the installed air compressor can be switched appropriately and efficiently, so that it is possible to easily realize the extension of the device life, the reduction of the operation cost, or the reduction of the environmental load.

It is a block diagram which shows the structure of the compressed air supply system concerning 1st Embodiment. It is an example of composition of operation setting data. It is a structural example of driving | running state data. It is a structural example of target value data. It is a flowchart which shows the air compressor control process of the air compressor control apparatus concerning 1st Embodiment. It is explanatory drawing which shows the example of switching control of an air compressor. It is another example of setting of operation setting data. It is explanatory drawing which shows the other switching control example of an air compressor. It is a graph which shows the rotation speed control characteristic with respect to an inverter machine. It is explanatory drawing which shows the example of switching control using an inverter machine. It is a graph which shows the rotation speed control characteristic with respect to a some inverter machine. It is explanatory drawing which shows the example of switching control using a some inverter machine. It is an example of composition of operation setting data at the time of rotation operation. It is an example of rotation operation. It is an example of composition of other operation setting data at the time of rotation operation. It is another example of rotation operation. It is an example of composition of operation setting data which consists of a plurality of control patterns. It is a structural example of an operation schedule. It is a display example of a monitoring screen.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a compressed air supply system according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a compressed air supply system according to the first embodiment.

  The compressed air supply system 1 collects compressed air generated by a plurality of air compressors AC (AC1, AC2,..., ACn) at a supply unit 20 and loads various utility facilities and building facilities in a factory. 40 (41, 42,..., 4 m) according to a change in the air pressure P indicating the pressure of the compressed air measured by the pressure gauge 30 at the supply unit 20 in the air compressor control device 10. It has a function of adjusting the air pressure P by switching and controlling the operating state of the air compressor AC.

  Among these, about air compressor AC, it consists of general air compressors, such as a screw type, which drive with an electric motor and produce | generate compressed air. These air compressors AC may be those using a constant speed rotation type electric motor, or those capable of adjusting the supply amount of compressed air using an inverter control type electric motor whose rotation speed can be adjusted in a stepless manner. May be used. Further, as will be described later, these constant speed rotation type and inverter control type air compressors AC may be used in parallel. In the present embodiment, a case where the compressed air supply system 1 is configured by an air compressor AC using an electric motor of a constant speed rotation type will be described as an example.

The supply unit 20 is a supply path that collects the compressed air generated by each air compressor AC and distributes the compressed air to the load 40. If necessary, the supply unit 20 temporarily stores the compressed air, and dries the compressed air. For example, a dryer for cleaning, a filter for purifying the compressed air, and an air header for distributing the compressed air to each load 40 are included.
The pressure gauge 30 is composed of a pressure transmitter that measures the pressure of gas with a pressure sensor, and is provided in an arbitrary facility that constitutes the supply unit 20, and measures the air pressure P of the collected compressed air to measure the air compressor. It has a function of outputting to the control device 10.
The monitoring device 50 is a terminal device for monitoring the control status of the air compressor AC in the air compressor control device 10 by performing data communication with the air compressor control device 10 via a communication line such as a LAN. .

  In the present embodiment, in the air compressor control device 10, operation setting data in which the priority order to be selected as a target of switching control for each air compressor AC is preset is stored in the storage unit, and the operation setting data Based on the priority order, the air compressor AC to be subjected to switching control is selected from the air compressors AC, and the selected operating state of the air compressor AC is discharged according to the change in air pressure. Switching control is performed to a loaded state or an unloaded state in which compressed air is not discharged.

[Air compressor controller]
Next, with reference to FIG. 1, the structure of the air compressor control apparatus 10 concerning this Embodiment is demonstrated in detail.
The air compressor control device 10 is composed of a control device such as a controller that automatically controls various equipment and field devices as a whole. The main functional units include a measurement processing unit 11, a storage unit 12, a switching control unit 13, An operation command unit 14 and a communication unit 15 are provided.

  The measurement processing unit 11 includes a dedicated communication interface circuit, and has a function of acquiring the pressure of the compressed air measured by the pressure gauge 30, that is, the air pressure P by communicating with the pressure gauge 30.

The storage unit 12 includes a storage device such as a semiconductor memory or a hard disk, and has a function of storing various processing information and a program 12P used by the switching control unit 13.
The program 12P is a program that realizes various processing units by being read from the storage unit 12 and executed by the switching control unit 13, and is previously stored in an external device (not shown) or a recording medium (not shown). It is read and stored in the storage unit 12.
Main processing information stored in the storage unit 12 includes operation setting data 12A, operation state data 12B, and target value data 12C.

  The operation setting data 12A is data indicating a priority order for selecting the air compressor AC as a target for switching control. FIG. 2 is a configuration example of operation setting data. Here, five air compressors AC1, AC2, AC3, AC, and AC5 are shown as examples, and the load priority order and the unload priority order are individually set for each air compressor AC. Usually, the operating state of the air compressor AC includes a stop state in which the electric motor is stopped, an unload state in which the electric motor is operating but not discharging compressed air, and a compressed air in which the electric motor operates. There are three operation states, that is, a load state in which gas is discharged.

  In the operation setting data 12A, the load priority order is a numerical value indicating the order in which the air compressor AC that is to be controlled to be switched to the load state is selected from the air compressors AC that are in the unload state. In the operation setting data 12A, the unload priority is a numerical value indicating the order of selecting the air compressor AC that is to be controlled to be switched to the unload state from the air compressor AC in the load state. These numerical values indicate that the lower the priority, the higher the priority. In the example of FIG. 2, the air compressor AC1 has the highest load priority, and the air compressor AC5 has the highest unload priority. is there.

The operation state data 12B is data indicating the operation state of each air compressor AC. FIG. 3 is a configuration example of the operation state data. Here, five air compressors AC1, AC2, AC3, AC, and AC5 are shown as examples, and for each of these air compressors AC, three operation states of a load state, an unload state, and a stop state are registered. Has been.
The target value data 12C is data indicating a specified range in which the air pressure P of the compressed air in the supply unit 20 is held. FIG. 4 is a configuration example of target value data. Here, an upper limit value PH and a lower limit value PL of the specified range are set, respectively.

  The switching control unit 13 includes a CPU and its peripheral circuits, and includes an arithmetic processing unit that executes various processes by reading and executing the program 12P of the storage unit 12, and the operation setting data 12A read from the storage unit 12 A function of selecting an air compressor AC to be subjected to switching control from among the air compressors based on the priority order, and a change in the air pressure P obtained by the measurement processing unit 11 indicating the operation state of the selected air compressor AC. Accordingly, it has a function of switching control to a loaded state in which compressed air is discharged or an unloaded state in which compressed air is not discharged.

  Specifically, the switching control unit 13 periodically compares the air pressure P with the upper limit value PH and the lower limit value PL of the target value data 12C. Here, when the compressed air consumption at the load 40 increases and the air pressure P decreases to the lower limit PL, the new air compressor AC is switched to the load state in order to increase the air pressure P. At this time, the air compressor AC having the highest load priority in the operation setting data 12A among the air compressors AC in the unload state confirmed based on the operation state data 12B is selected and switched to the load state. .

  Further, when the compressed air consumption at the load 40 is reduced and the air pressure P increases to the upper limit value PH, one of the air compressors AC in the loaded state switches to the unloaded state in order to reduce the air pressure P. Be controlled. At this time, the air compressor AC having the highest unload priority in the operation setting data 12A is selected from the air compressors AC in the load state confirmed based on the operation state data 12B, and is switched to the unload state. The

  In addition, when the number of unloaded air compressors AC becomes zero, the switching control unit 13 refers to the operation setting data 12A and the operation state data 12B in the storage unit 12 and performs the air compression in the stopped state. Among the compressors AC, the air compressor AC having the highest load priority is activated and controlled to be switched to the unloaded state. As a result, when the air pressure P further decreases and the new air compressor AC is switched to the load state, the air compressor AC in the unload state is immediately switched to the load state in descending order of load priority. Can be controlled.

  Further, the switching control unit 13 has a function of switching and controlling the compressed air AC having the highest unload priority in the operation setting data 12A to the stopped state among the compressed air AC that has been switched from the loaded state to the unloaded state. Have. Thereby, switching control to a stop state can be carried out in order from the higher unload priority among the excess compressed air AC.

The operation command unit 14 includes a dedicated communication interface circuit, and has a function of commanding the switching of the operation state to the target air compressor AC based on the control content determined by the switch control unit 13. ing.
The communication unit 15 performs data communication with the monitoring device 50 via a communication line such as a LAN, thereby various types of control status of the air compressor AC in the air compressor control device 10 such as the operation state data 12B of the storage unit 12. It has a function of transmitting processing information to the monitoring device 50.

[Operation of First Embodiment]
Next, the operation of the air compressor control device 10 according to the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart illustrating an air compressor control process of the air compressor control device according to the first embodiment.

In the air compressor control device 10, the measurement processing unit 11 periodically acquires the air pressure P from the pressure gauge 30 (step 100).
The switching control unit 13 compares the air pressure P newly acquired by the measurement processing unit 11 with the lower limit value PL with reference to the target value data 12C of the storage unit 12 (step 101).

  Here, when the air pressure P is equal to or lower than the lower limit value PL for a certain period (step 101: YES), the switching control unit 13 refers to the operation setting data 12A and the operation state data 12B in the storage unit 12 to cancel the operation. The air compressor AC having the highest load priority is selected from the air compressors AC in the load state (step 102), and an instruction to control the selected air compressor AC to be switched to the load state is output to the operation command unit 14. At the same time, the operation state of the air compressor AC selected from the operation state data 12B is updated to the load state (step 103), and the process returns to step 100.

  Thereby, an operation state switching command is output from the operation command unit 14 to the target air compressor AC, and the target air compressor AC switches the operation state to the load state. For this reason, the amount of compressed air discharged to the supply unit 20 increases, and the air pressure P rises from the lower limit value PL and is maintained within the specified range.

On the other hand, when the air pressure P does not become lower than the lower limit value PL in step 101 (step 101: NO), the switching control unit 13 compares the air pressure P with the upper limit value PH of the target value data 12C ( Step 104).
Here, if the air pressure P does not exceed the upper limit PH continuously for a certain period (step 104: NO), the process returns to step 100.

  When the air pressure P is equal to or higher than the upper limit PH (step 104: YES), the switching control unit 13 refers to the operation setting data 12A and the operation state data 12B in the storage unit 12 to load the load state. The air compressor AC having the highest unload priority is selected from among the air compressors AC in step (step 105), and an instruction to switch the selected air compressor AC to the unload state is output to the operation command unit 14. At the same time, the operation state of the air compressor AC selected from the operation state data 12B is updated to the unload state (step 106), and the process returns to step 100.

  Accordingly, an operation state switching command is output from the operation command unit 14 to the target air compressor AC, and the target air compressor AC switches the operation state to the unload state. For this reason, the amount of compressed air discharged to the supply unit 20 decreases, and the air pressure P decreases from the upper limit value PH and is maintained within the specified range.

FIG. 6 is an explanatory diagram illustrating an example of air compressor switching control, in which the horizontal axis indicates time, and the vertical axis indicates compressed air consumption, that is, the load amount.
When the load priority is set in the order of “1” to “5” for the air compressors AC1 to AC5 as in the operation setting data 12A shown in FIG. After the air compressor AC1 is first switched to the load state, the air compressors AC2 to AC5 are sequentially controlled to the load state as the load amount monotonously increases.

  When the unload priority is set in the order of “5” to “1” for the air compressors AC1 to AC5 as in the operation setting data 12A shown in FIG. 2, all the air compressors are set. From the time when AC1 to AC5 are in the load state, the air compressors AC5 to AC1 are sequentially controlled to the unload state as the load amount monotonously decreases.

  Therefore, according to the setting example of the operation setting data 12A shown in FIG. 2, the so-called first-in last-out, which controls the switching of the air compressor AC to the unloading state in the reverse order to the order of switching to the loading state. Control (FILO: First In Last Out) can be executed. For this reason, for example, the air compressor AC with good air compression efficiency can be operated with priority, and the reduction of the operating cost and the reduction of the environmental load due to the reduction of power consumption can be realized.

FIG. 7 shows another setting example of the operation setting data. FIG. 8 is an explanatory diagram showing another example of switching control of the air compressor.
In FIG. 7, compared with FIG. 2, the unload priority is set in the order of “1” to “5” for the air compressors AC1 to AC5. For this reason, the order of switching to the loaded state is the same as in FIG. 6, but the order of switching to the unloaded state is different. That is, the air compressors AC1 to AC5 are sequentially controlled to the load state as the load amount monotonously decreases from the time when all the air compressors AC1 to AC5 are in the load state.

  Therefore, according to the setting example of the operation setting data 12A shown in FIG. 7, so-called first-in first-out control (FIFO: First) that switches the air compressor AC to the unload state in the same order as the order in which the control is switched to the load state. In First Out). For this reason, in the setting example of FIG. 7, an air compressor having a high load priority / unload priority setting, for example, the air compressor AC1, can be switched preferentially as a capacity adjuster. it can. On the other hand, an air compressor with a low load priority / unload priority setting, for example, the air compressor AC5, is difficult to load as a base operating machine, but once loaded, it can be operated as a machine that preferentially continues the loading state. it can. This makes it possible to apply controls that take advantage of the characteristics of individual air compressors, such as operating a machine with small capacity and low unload power as a capacity regulator, and operating a machine with large capacity and high unload power as a base machine. it can.

[Effect of the first embodiment]
As described above, in the present embodiment, the storage unit 12 stores the operation setting data 12A in which the priority order to be selected as the switching control target for each air compressor AC is preset in the air compressor control device 10. Then, the switching control unit 13 selects the air compressor AC to be subjected to switching control from the air compressors AC based on the priority order of the operation setting data 12A, and sets the operating state of the selected air compressor AC. In accordance with a change in air pressure, switching control is performed between a loaded state in which compressed air is discharged or an unloaded state in which compressed air is not discharged.

  Thereby, the load priority and unload priority of operation setting data 12A can be arbitrarily set based on the efficiency, capacity, and control method of each air compressor AC. For this reason, even when air compressors having different efficiency, capacity, and control method coexist, it is possible to realize appropriate operation utilizing the characteristics of each air compressor. Therefore, the installed air compressor can be switched appropriately and efficiently, so that it is possible to easily realize the extension of the device life, the reduction of the operation cost, or the reduction of the environmental load.

[Second Embodiment]
Next, an air compressor control device according to a second embodiment of the present invention will be described.
In the first embodiment, the air compressor AC using a constant speed rotation type electric motor, that is, the case where the compressed air supply system 1 is configured by a load / unload machine is described as an example. In the embodiment, a case where a load / unload machine and an air compressor AC using an inverter-controlled electric motor, that is, an inverter machine are mixed will be described.

In the air compressor control device 10 according to the present embodiment, the switching control unit 13 is based on the PID output of the air pressure P with respect to the preset target pressure P ′ with respect to the inverter machine of the air compressor AC. It has a function of finely adjusting the air pressure by outputting a rotational speed command according to the change of the air pressure P. At this time, the PID output of the air pressure P may be calculated by the switching control unit 13, or the PID of the air pressure P calculated based on the input air pressure P by the pressure controller provided outside the air compressor control device 10. Output may be used.
Other configurations of the air compressor control device 10 according to the present embodiment are the same as those in the first embodiment, and a detailed description thereof is omitted here.

[Operation of Second Embodiment]
Next, the operation of the air compressor control device 10 according to the present embodiment will be described with reference to FIGS. 9 and 10. FIG. 9 is a graph showing the rotational speed control characteristics for the inverter machine. FIG. 10 is an explanatory diagram illustrating an example of switching control using an inverter machine. The overall air compressor control process is the same as in FIG. 5 described above, and a detailed description thereof is omitted here.

In the present embodiment, the switching control unit 13 uses the PID output of the air pressure P as the rotation speed command output N of the inverter machine. Therefore, the inverter machine increases / decreases the rotational speed so that the air pressure P matches the target pressure P ′.
In the rotational speed control characteristic of FIG. 9, 0% -100% of the rotational speed command output N is assigned to the PID output range 0% -100% of the air pressure P. At this time, Nmax is the maximum rotational speed of the inverter machine, and the rotational speed command upper limit Nlim is set to 90% of the maximum rotational speed Nmax in consideration of the characteristics of the inverter.

In the case of a normal load, the switching control unit 13 controls the rotational speed command output N for the inverter machine between the minimum rotational speed Nmin and the maximum rotational speed Nmax, but the load decreases and the PID output decreases. Then, the rotational speed command output N is reduced to 0% exceeding the minimum rotational speed Nmin. Further, when the rotational speed command output N falls below the unload rotational speed Nunload, the switching control unit 13 performs switching control of the inverter machine from the load state to the unload state.
Further, when the load increases from this state and the PID output increases, the switching control unit 13 gradually increases the rotational speed command output N, and when the load rotational speed Nload is reached, the switching control unit 13 unloads the inverter. Controls switching from the load state to the load state.

In the case of an inverter machine that does not have an unload operation function, the switching control unit 13 unloads the inverter machine even if the load decreases and the PID output decreases and the rotational speed command output N falls below the minimum rotational speed Nmin. The load state is maintained without switching control to the state. At this time, the inverter machine itself maintains the minimum rotational speed Nmin even if the rotational speed command output N lower than the minimum rotational speed Nmin is instructed.
Further, when the load increases from this state and the PID output increases, the switching control unit 13 gradually increases the rotational speed command output N, and when the minimum rotational speed Nmin is reached, the switching control unit 13 rotates the inverter. Number control is resumed.

  Therefore, as in the operation setting data 12A shown in FIG. 2, the load priorities are set in the order of “1” to “5” for the air compressors AC1 to AC5, and the air compressor AC1 is an inverter machine. In this case, as shown in FIG. 10, at the start of the air compressor control, the inverter AC1 is first controlled to be switched from the stopped state to the unloaded state, and starts to rotate at the minimum rotation speed Nmin, thereby increasing the load amount. Accordingly, when the rotational speed command output N increases and reaches the load rotational speed Nload, the inverter AC1 is controlled to be switched from the unload state to the load state, and after reaching the minimum rotational speed Nmin, the rotational speed command output N is reached. Thus, the rotational speed control of the inverter machine AC1 is started.

  Thereafter, the rotational speed command output N rises according to the increase in the load amount, and when the rotational speed command upper limit Nlim is reached, the air compressor AC2 is switched to the load state according to the load priority order. As the load increases monotonously, the air compressors AC3 to AC5 are sequentially controlled to the load state. At this time, since the air pressure P increases stepwise when the new air compressor AC is switched to the load state, the rotational speed command output N decreases by the increase of the air pressure P, and the air pressure P is set to the target. The rotational speed of the inverter machine AC1 is decreased so as to match the pressure P ′. Thereby, the compressed air supply total amount from each air compressor AC changes smoothly according to a load amount.

  Further, as in the operation setting data 12A shown in FIG. 2, the unload priority is set in the order of “5” to “1” for the air compressors AC1 to AC5, and all the air compressors AC1 are set. When the load amount decreases and the PID output decreases from the time point when AC5 is in the load state, the rotation speed command output N decreases and the rotation speed of the inverter AC1 matches the air pressure P with the target pressure P ′. Decreases. Thereafter, when the rotational speed command output N falls below the minimum rotational speed Nmin, the rotational speed of the inverter AC1 maintains the minimum rotational speed Nmin, and when the rotational speed command output N falls below the unload rotational speed Nunload. The inverter AC1 is controlled to be switched to the unload state according to the unload priority order.

  Thereafter, as the load amount monotonously decreases, the air compressors AC5 to AC1 are sequentially controlled to the unload state. At this time, when the new air compressor AC is switched to the unloaded state, the air pressure P decreases stepwise, so the rotational speed command output N increases by the amount of decrease in the air pressure P. For this reason, when the rotational speed command output N reaches the load rotational speed Nload, the inverter AC1 is switched to the load state, and then the rotational speed of the inverter AC1 is set so that the air pressure P matches the target pressure P ′. To rise. Thereby, the compressed air supply total amount from each air compressor AC changes smoothly according to a load amount.

In addition, when a plurality of inverter machines are installed, the switching control unit 13 operates the inverter machines that can be used so that the weight of the PID output of the air pressure P functions regardless of the number of inverter machines loaded. The slope of the rotational speed control characteristic is calculated by dividing the sum of the abilities by the sum of the operation abilities by the inverter machine during the road operation.
FIG. 11 is a graph showing rotation speed control characteristics for a plurality of inverter machines. Here, the rotational speed control characteristics when two inverter machines are used are shown. When the operating capabilities of the two inverter machines are equal, the inclination during one unit operation is twice that during two unit operation.

  FIG. 12 is an explanatory diagram showing an example of switching control using a plurality of inverter machines. Like the operation setting data 12A shown in FIG. 2, the load priorities are set in the order of “1” to “5” for the air compressors AC1 to AC5, and the air compressors AC1 and AC2 are the inverter machines. In this case, as shown in FIG. 12, the inverter AC1 is first controlled to be switched to the load state based on the load priority order, and the rotational speed command output N of the inverter AC1 is determined based on the rotational speed control characteristics during the operation of one unit. Calculated.

Further, when the rotational speed command output N reaches the rotational speed command upper limit Nlim, the inverter AC2 is controlled to be switched to the load state, and the rotational speed commands of the inverters AC1 and AC2 are based on the rotational speed control characteristics when two units are operated. An output N is calculated.
Thereafter, the rotational speed command output N rises according to the increase in the load amount, and when the rotational speed command upper limit Nlim is reached, the air compressor AC3 is switched to the load state according to the load priority order. As the load amount monotonously increases, the air compressors AC4 to AC5 are sequentially switched to the load state.

  Further, as in the operation setting data 12A shown in FIG. 2, the unload priority is set in the order of “5” to “1” for the air compressors AC1 to AC5, and all the air compressors AC1 are set. When AC5 is in the load state, when the load amount decreases and the PID output decreases, the rotational speed command output N decreases, and the inverters AC1 and AC2 are made to match the air pressure P with the target pressure P ′. The rotational speed decreases. Thereafter, when the rotational speed command output N decreases to the minimum rotational speed Nmin, the air compressor AC5 other than the inverter machine is controlled to be switched to the unload state according to the unload priority order.

  Further, the air compressors AC4 and AC3 other than the inverter machine are controlled to be switched to the unloaded state according to the monotonous decrease in the load amount. Thereafter, when the rotational speed command output N falls below the unload rotational speed Nunload, the inverter machine AC2 is switched to the unload state, and finally, the inverter machine AC1 is controlled to be switched to the unload state.

[Effect of the second embodiment]
As described above, in the present embodiment, the switching control unit 13 outputs the rotational speed command corresponding to the change of the air pressure P to the inverter-controlled air compressor of the air compressor AC. Since the air pressure P is finely adjusted to coincide with the atmospheric pressure P ′, the total amount of compressed air supplied from each air compressor AC can be smoothly changed in accordance with the change in the load amount. For this reason, it is possible to supply compressed air in an appropriate amount without excess or deficiency, and it is possible to easily realize a reduction in operating cost or a reduction in environmental load.

[Third Embodiment]
Next, an air compressor control device 10 according to a third embodiment of the present invention will be described.
In the first embodiment, the case has been described as an example in which different ranks with no overlap are assigned as the load priority order and the unload priority order for each air compressor AC. In the present embodiment, an example will be described in which the same load priority and unload priority are assigned to a plurality of air compressors AC, and the air compressors AC are rotated.

In the air compressor control device 10 according to the present embodiment, when the switching control unit 13 selects an air compressor having an arbitrary priority, when there are a plurality of air compressors having the priority, these air compressors Based on the frequency of use of the compressor AC, the air compressor is sequentially rotated and selected.
Other configurations of the air compressor control device 10 according to the present embodiment are the same as those in the first embodiment, and a detailed description thereof is omitted here.

[Operation of Third Embodiment]
Next, the operation of the air compressor control device 10 according to the present embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is a configuration example of operation setting data during the rotation operation. FIG. 14 is an example of rotation operation. The overall air compressor control process is the same as in FIG. 5 described above, and a detailed description thereof is omitted here.

In step 102 in FIG. 5, when the air compressor AC that is newly switched to the load state is selected, the switching control unit 13 refers to the load priority order set in the operation setting data 12 </ b> A of the storage unit 12.
Here, when the same load priority order is set for a plurality of air compressors AC, the switching control unit 13 uses the air compressors AC so that the frequency of use is equal among the air compressors AC. The air compressor AC that is newly switched to the load state is selected.

  In the operation setting data example of FIG. 13, load priorities “1” and “2” are set for the air compressors AC1 and AC5, and the same load priorities are set for the air compressors AC2, AC3 and AC4. “3” is set. Therefore, when the switching control unit 13 selects an air compressor AC that is newly controlled to be switched to the load state from the air compressors AC1 to AC5, as shown in FIG. 14, first, the load priority “1” is selected. The air compressor AC1 is selected, the air compressor AC5 having the load priority “2” is selected, and then the air compressor AC2, AC3, AC4 having the load priority “3” is selected. To do.

  At this time, the switching control unit 13 compares the use frequency such as the accumulated operation time and the accumulated number of activations recorded in advance for the air compressors AC2, AC3, AC4, and among these air compressors AC2, AC3, AC4. The air compressor AC with the least usage frequency is selected from the above.

Such a rotation operation is not limited to any one of the priorities, and the rotation operation may be performed with a plurality of different priorities.
FIG. 15 is a configuration example of other operation setting data during the rotation operation. FIG. 16 shows another example of rotation operation.

  In the operation setting data example of FIG. 15, the same load priority “1” is set for the air compressors AC1 and AC5, and the same load priority “3” is set for the air compressors AC2, AC3 and AC4. "Is set. Therefore, when the switching control unit 13 selects an air compressor AC that is newly controlled to switch to the load state from the air compressors AC1 to AC5, first, as shown in FIG. Of the air compressors AC1 and AC2 of the air compressor AC1 and AC2, the air compressor AC having the lowest usage frequency is selected, and then the air compressor AC2, AC3 and AC4 of the load priority “3” having the lowest usage frequency is selected. The compressor AC will be selected.

[Effect of the third embodiment]
As described above, in the present embodiment, when the switching control unit 13 selects an air compressor AC having an arbitrary priority, if there are a plurality of air compressors AC having the priority, these air compressors Since these air compressors AC are sequentially rotated and selected based on the frequency of use of AC, the rotation operation related to a specific air compressor AC can be executed with an arbitrary priority. As a result, not only the service life of the specific air compressor AC that performs the rotation operation can be extended, but also the operation priority with the air compressor AC other than the specific air compressor AC can be easily set. Appropriate operation utilizing the characteristics of the air compressor can be realized.

In the present embodiment, the case where the air compressor AC is switched to the load state has been described as an example. However, in step 105 of FIG. 5, the air compressor AC in the load state is switched to the unload state. In this case, the rotation operation can be applied in the same manner as described above.
Note that the frequency of use of each air compressor AC is determined when the air compressor AC actually selected is switched to the loaded state or unloaded state in steps 103 and 106 in FIG. 5. What is necessary is just to count time and the frequency | count of integration starting, for example, and to record it on the operation state data 12B of the memory | storage part 12.

[Fourth Embodiment]
Next, an air compressor control device 10 according to a fourth embodiment of the present invention will be described.
In the first embodiment, the case where the switching control of the air compressor AC is performed based on one operation setting data 12A has been described as an example. In the present embodiment, a case will be described in which a plurality of operation setting data 12A having different setting contents are switched according to the operation schedule.

In the air compressor control device 10 according to the present embodiment, the storage unit 12 stores a plurality of operation setting data having different priorities set for each air compressor AC. Further, the switching control unit 13 selects the air compressor AC to be subjected to switching control based on the priority of any one of the operation setting data selected from the operation setting data according to a preset operation schedule. It has a function to do.
Other configurations of the air compressor control device 10 according to the present embodiment are the same as those in the first embodiment, and a detailed description thereof is omitted here.

[Operation of Fourth Embodiment]
Next, the operation of the air compressor control apparatus 10 according to the present embodiment will be described with reference to FIGS. 17 and 18. FIG. 17 is a configuration example of operation setting data composed of a plurality of control patterns. FIG. 18 is a configuration example of an operation schedule. The overall air compressor control process is the same as in FIG. 5 described above, and a detailed description thereof is omitted here.

In step 102 in FIG. 5, when the air compressor AC that is newly switched to the load state is selected, the switching control unit 13 refers to the load priority order set in the operation setting data 12 </ b> A of the storage unit 12.
Here, the switching control unit 13 first refers to the operation schedule of the storage unit 12, confirms the control pattern to be applied at the present time, acquires the operation setting data 12A corresponding to the control pattern, and performs this operation. Based on the load priority order of the setting data 12A, the air compressor AC that is newly switched to the load state is selected.

Similarly, in step 105 of FIG. 5, when selecting the air compressor AC to be switched from the loaded state to the unloaded state, the switching control unit 13 unloads set in the operation setting data 12 </ b> A of the storage unit 12. Refer to priority.
Here, the switching control unit 13 first refers to the operation schedule of the storage unit 12, confirms the control pattern to be applied at the present time, acquires the operation setting data 12A corresponding to the control pattern, and performs this operation. Based on the unload priority order of the setting data 12A, the air compressor AC that is newly switched to the unload state is selected.

  In the operation setting data example of FIG. 17, five control patterns of “weekday 1”, “weekday 2”, “weekday 3”, “holiday”, and “special day” are set. In the example of the operation schedule in FIG. 18, which control pattern is applied to each day of the week is set for “this week”, “second week”, “third week”, and “fourth week”.

Therefore, for example, if the current day is Monday, the “Month” field of “This week” in the operation schedule of FIG. 18 is referred to, the control pattern “Weekday 1” is selected, and the operation setting data of FIG. The load priority order and unload priority order of the control pattern “weekday 1” are acquired as the operation setting data 12A.
For example, if the current day is Tuesday, the “Tue” column of “This week” in the operation schedule of FIG. 18 is referred to, the control pattern “Holiday” is selected, and control is performed from the operation setting data of FIG. The load priority and unload priority of the pattern “holiday” are acquired as the operation setting data 12A.

[Effect of the fourth embodiment]
As described above, according to the present embodiment, the storage unit 12 stores a plurality of operation setting data having different priorities set for each air compressor, and the switching control unit 13 sets a preset operation. Since the air compressor to be subject to switching control is selected based on the priority of any one of the operation setting data selected from the operation setting data according to the schedule, the use of compressed air in each period Even when the amount is different, the air compressor AC to be switched to the load state or the unload state can be selected based on the corresponding priority order, and the operation of the air compressor can be performed according to the operation content of the load 40. It becomes possible to control appropriately.

[Fifth Embodiment]
Next, an air compressor control device according to a fifth embodiment of the present invention will be described.
In 1st Embodiment, the point which transmits the various process information regarding the control condition of the air compressor AC in the air compressor control apparatus 10 from the communication part 15 with respect to the monitoring apparatus 50 was demonstrated.
In the present embodiment, a case will be described in which the switching control unit 13 generates control status data including the air compressor AC that is switched to a loaded state or an unloaded state in the next switching control.

In the air compressor control device 10 according to the present embodiment, the switching control unit 13 loads or unloads the air compressor AC in the next switching control based on the priority order of the operation setting data 12A. The air compressor AC to be switched to is selected, and the selection result is output as control status data indicating the switching control status for each air compressor AC.
Other configurations of the air compressor control device 10 according to the present embodiment are the same as those in the first embodiment, and a detailed description thereof is omitted here.

[Operation of Fifth Embodiment]
Next, the operation of the air compressor control device 10 according to the present embodiment will be described with reference to FIG. FIG. 19 is a display example of a monitoring screen. The overall air compressor control process is the same as in FIG. 5 described above, and a detailed description thereof is omitted here.

  In step 102 of FIG. 5, when selecting the air compressor AC to be newly switched to the load state, the switching control unit 13 is based on the load priority set in the operation setting data 12 </ b> A of the storage unit 12. As described above, after selecting the air compressor AC that is newly switched to the load state, the air compressor AC that switches from the unload state to the load state by the next switching control is selected from the remaining air compressors AC. Then, the air compressor AC that switches from the stop state to the unload state in the next switching control is selected, and the selection result is output to the storage unit 12 as control status data indicating the control status for each air compressor AC.

  In step 105 in FIG. 5, when the air compressor AC to be newly switched to the unload state is selected, the switch control unit 13 sets the unload priority order set in the operation setting data 12 </ b> A of the storage unit 12. As described above, after selecting an air compressor AC that is newly switched to the unload state, as described above, the remaining air compressor AC is switched from the load state to the unload state by the next switching control. The air compressor AC and the air compressor AC that switches from the unloaded state to the stopped state in the next switching control are selected, and the selection result is sent to the storage unit 12 as control status data indicating the control status for each air compressor AC. Output.

In response to the control status transmission request from the monitoring device 50, the communication unit 15 performs various processes related to the control status of the air compressor AC in the air compressor control device 10 such as the operation status data 12 </ b> B and the control status data from the storage unit 12. Information is acquired and transmitted to the monitoring apparatus 50 via a communication line.
The monitoring device 50 transmits a control status transmission request to the air compressor control device 10 at regular intervals or in response to an operator operation, and based on various processing information returned in response thereto, as shown in FIG. The monitor screen is displayed on the screen. In FIG. 19, the control status for the five air compressors AC1 to AC5 is displayed on the screen.

  Among these, in the “operation status” column, the current operation status is displayed based on the operation state data acquired from the air compressor control device 10. Specifically, it is displayed that the air compressor AC1 is in the “running” state, that is, the electric motor is rotating, and is in the “load” state, that is, the load state in which compressed air is discharged. Similarly, it is displayed that the air compressor AC2 is in the “running” state, that is, the electric motor is rotating, and is in the “no load” state, that is, the unloading state in which compressed air is not discharged. Further, it is displayed that the air compressors AC3 to AC5 are in a “stop” state, that is, a stop state in which the electric motor is not rotating.

  In the “number control status” column, the current number control status is displayed based on the control status data acquired from the air compressor control device 10. Specifically, the air compressor AC2 is displayed in the “next load machine” column as the air compressor to be switched from the unload state to the load state next time, and the “next starter” column next time. The air compressor AC3 is displayed as an air compressor that performs switching control from the stop state to the unload state. In the “next unload machine” column, the air compressor that performs switching control from the load state to the unload state next time is displayed. The air compressor AC1 is displayed.

  In the “next operation / next stop” column of the “operation status” column, a round symbol is displayed to indicate that the air compressor AC2 is an air compressor that is next controlled to switch from the unload state to the stop state. Therefore, a round symbol is displayed to indicate that the air compressor AC3 is an air compressor that is next controlled to switch from the stopped state to the unloaded state.

[Fifth Embodiment]
As described above, in the present embodiment, the switching control unit 13 uses the air compressor AC to switch from the air compressor AC to the load state or the unload state based on the priority order of the operation setting data 12A. The compressor AC is selected, and the selection result is output as control status data indicating the control status for each air compressor AC. Therefore, the switching control status for each air compressor AC in the air compressor control device 10, particularly, It is possible to easily confirm the future switching control status with respect to the load fluctuation after the present time.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Compressed air supply system, 10 ... Air compressor control apparatus, 11 ... Measurement processing part, 12 ... Memory | storage part, 12A ... Operation setting data, 12B ... Operation state data, 12C ... Target value data, 12P ... Program, 13 ... Switching control unit, 14 ... operation command unit, 15 ... communication unit, 20 ... supply unit, 30 ... pressure gauge, 40, 41, 42, ..., 4 m ... load, 50 ... monitoring device, AC, AC1, AC2, AC3 AC4, AC5 to ACn ... air compressor, P ... air pressure, PH ... upper limit value, PL ... lower limit value, P '... target pressure, N ... rotational speed command output, Nmax ... maximum rotational speed, Nlim ... rotational speed command Upper limit, Nmin ... minimum rotation speed, Nload ... load rotation speed, Nunload ... unload rotation speed.

Claims (5)

A plurality of air compressors for generating compressed air;
A supply unit that collects compressed air generated by the air compressor and supplies the compressed air to a load;
An air compressor control device that adjusts the air pressure by switching and controlling the operating state of the air compressor according to a change in air pressure indicating the pressure of the compressed air measured by the supply unit,
The air compressor control device includes:
A storage unit for storing operation setting data in which a priority order to be selected as a target of the switching control for each air compressor is set in advance;
Based on the priority of the operation setting data, select the air compressor that is the target of the switching control from the air compressor, the operating state of the selected air compressor according to the change in the air pressure, look including a switching control unit for switching control to the unloaded state of not ejecting the loaded state or the compressed air discharging the compressed air,
When the air compressor having an arbitrary priority order is selected when there are a plurality of air compressors having the priority order, the switching control unit selects the air compressor based on the frequency of use of these air compressors. Compressed air supply system characterized by sequential rotation . The compressed air supply system according to claim 1.
The switching control unit finely adjusts the air pressure by outputting a rotation speed command corresponding to the change in the air pressure to an inverter-controlled air compressor among the air compressors. Compressed air supply system. The compressed air supply system according to claim 1.
The storage unit stores a plurality of operation setting data having different priorities set for the air compressors,
The switching control unit selects an air compressor to be subjected to the switching control based on a priority order of any one of the operation setting data selected from the operation setting data according to a preset operation schedule. Compressed air supply system characterized by the above. The compressed air supply system according to claim 1.
The switching control unit selects, based on the priority order of the operation setting data, the air compressor to be switched to the load state or the unload state in the next switching control from among the air compressors. A compressed air supply system that outputs a result as control status data indicating a control status for each of the air compressors. A plurality of air compressors generating compressed air;
A supply unit that collects compressed air generated by the air compressor and supplies the compressed air to a load;
An air compressor control device that adjusts the air pressure by switching and controlling the operating state of the air compressor according to a change in air pressure indicating the pressure of the compressed air measured by the supply unit. With steps,
The air compressor control step includes
The air compressor that is the target of the switching control among the air compressors based on the priority order set as the target of the switching control that is set in advance for each air compressor in the operation setting data of the storage unit. A selection step to select,
The operating state of the selected the air compressor, according to a change in the air pressure, see contains a switching control step for switching control to the compressed air unloaded state of not ejecting the loaded state or the compressed air for ejecting,
In the switching control step, when there are a plurality of air compressors having the priority order when selecting the air compressors having an arbitrary priority order, the air compressors are selected based on the use frequency of the air compressors. A method for supplying compressed air, wherein the selection is performed by sequential rotation .

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