JPH0319561B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention is directed to all machines operating in parallel in order to satisfy a total capacity requirement given from the outside to machines to be controlled, such as blowers and pumps, which have the capacities of a plurality of different types or the same type of single machine. The optimal combination is determined from among the combinations of
This invention relates to a method for controlling the number of operating vehicles by issuing a stop command. [Technical Background of the Invention] When controlling a controlled machine such as a blower to maintain a constant discharge pressure, in a general process, the suction valve opening of each unit is controlled according to the required air volume, and the number of units in operation at that time Just as we say that we control the number of blowers when the air volume cannot be satisfied, we control the number of operating machines to be controlled to satisfy the required value, that is, the total capacity required value, determined by a predetermined method. , rotational speed control, discharge valve opening degree control, etc. are often combined to perform control. In that case, the method for controlling the number of vehicles in operation is as follows:
If the total capacity requirement cannot be satisfied with the number of machines in operation at that time, the output obtained by combining the machines to be controlled, that is, the total capacity, is divided into multiple steps, or stages, and the control targets are divided in advance to obtain the output for each step. A method is often used in which combination patterns are prepared for each machine and the optimal combination pattern is determined from among them. Here, as an example, control of the number of five blowers, two small-capacity blowers, one medium-capacity blower, and two large-capacity blowers, will be described. Table 1 shows the air blowing capacity of each of the above-mentioned blowers in this example (shown as a relative value with the minimum capacity as a). Conventionally, a control device for controlling the number of devices as described above has been configured as shown in FIG. In FIG. 1, B1 to B5 are blowers as controlled objects. As for the control content, the discharge pressure P ₀ detected by the pressure detection device 1 is input to the total air volume calculation circuit 2. The total air volume calculation circuit 2 calculates the discharge pressure
For example, set the total air volume requirement Q _SV so that P ₀ is constant.
Calculate using PI calculation etc. Number control calculation circuit 3
A blower operating status signal is input to the input/output interface circuit 4 through the input/output interface circuit 4. In addition, the unit number control calculation circuit 3 divides the output, that is, the total air volume, obtained by the combination of multiple units (operating units are marked with ○) as shown in Table 2 into multiple steps, and calculates the total air volume corresponding to each step. Driving patterns are available. Then, the optimal driving pattern is selected from all combinations according to the flowchart shown in Fig. 2 (processes S1 to S4 in Fig. 2),
According to the operation pattern, start/stop commands are given to the five blowers B1 to B5 via the input/output interface circuit 4 (process S5 in FIG. 2). (b) Determining the total air volume step The ratio of the total air volume requirement value Q _SV to the maximum air volume Q _M of the total air volume step of the operating pattern at that time (hereinafter, this ratio is referred to as the "load ratio") is determined by the load ratio The step is changed when the following relationship is established with respect to the load factor upper limit value α _H and load factor lower limit value α _L set by the lower limit value setting circuit 5 (processing).
S1). Q _SV ／Q _M ＞α _H +DQ or Q _SV ／Q _M ＜α _L −DQ (DQ is the width of the dead zone) The new step is determined by choosing α _L from among all the steps.
A step satisfying <Q _SV /Q _M <α _H is selected (processing S2). (b) Determination of minimum starting/stopping frequency pattern Determining the starting/stopping frequency from the current operating pattern among all operating patterns corresponding to the step selected in (a), so that the starting/stopping frequency is minimized, that is, the state change is minimized. A plurality of driving patterns are selected (processing S3). (c) Determination of priority order In the multiple driving patterns selected in (b),
The driving pattern with the highest priority is selected according to the priority order determined by the priority order determination circuit 6 (processing S4). The priority order determining circuit 6 determines the priority order of the blowers _B1 to _B5 by automatic setting based on the cumulative operating time value or manual setting directly set by the operator. [Problems with the background art] In this conventional method, in determining the total air volume step in (a), multiple steps satisfying α _L < Q _SV /Q _M < α _H are selected, and all the corresponding operation patterns are selected. is the target. For example, in Table 2, α _H =
If _QSV is calculated as 3, 3a by the total air volume calculation circuit 2 at 100% and α _L = 50%, total air volume step Nos. 4, 5, and 6 are selected. Therefore, when selecting a new step, it is not possible to specify whether to select a step with a large total air volume or a step with a small total air volume. Furthermore, since the load factor upper limit value α _H and the load factor lower limit value α _L are fixed, the criteria for moving from the current step to a new step are always constant. Complex judgment processing such as moving to a step is not possible. By the way, when controlling the number of important devices such as blowers, pumps, etc., there is a concept of wanting to reduce power consumption even if the startup/stop frequency increases by controlling the number of devices, and a concept of wanting to reduce power consumption even if the power consumption increases slightly.・The idea is to reduce the frequency of stoppages and prevent equipment deterioration. Applying these two types of thinking to the number control method targeted here, in the former case it is sufficient to operate in steps with as small a total air volume as possible, and in the latter case it is sufficient to operate in steps with as large a total air volume as possible. become. As mentioned above, in the conventional method, the overall concept does not incorporate the judgment of whether to operate in a step with a large total air volume or a step with a small total air volume. I try to select a pattern that has a low frequency of starting/stopping from a pattern and has a high priority. Therefore, it has not been possible to control the number of devices in accordance with ideas such as wanting to reduce power consumption or reducing the frequency of starting and stopping by controlling the number of devices. [Objective of the Invention] The present invention as a whole aims to provide a method for controlling the number of units that can be set in advance to operate in steps with a large total air volume or in steps with a small total air volume, which enables advanced control and has good controllability. The purpose is [Summary of the Invention] In order to achieve the above object, the present invention divides the output obtained by the combination of the control target machines into a plurality of stages in advance when controlling the number of the control target machines. In a method of controlling the number of operating units in which all combination patterns belonging to a stage that satisfy the required output amount are selected, a target value of the load factor is first given by an operator, and then an upper limit value and a lower limit value are determined from this target value. The value is determined, and then candidate steps are determined from the load ratio between the current demand and the maximum capacity value of each step.Finally, among these steps, the initially sought target value and the current load ratio calculation value are determined. The reason is that the one with the smallest absolute value of deviation is selected. [Embodiment of the Invention] FIG. 3 shows the configuration of an embodiment of the present invention, and parts having the same functions as those in FIG. 1 are designated by the same reference numerals. The target load factor setting circuit 7 has the function of determining the target load factor α _dn by manual setting using a CRT (cathode ray tube) display device, etc., or automatically setting by other judgment processing, and providing that information to the number control calculation circuit 8. There is. The number-of-units control calculation circuit 8 selects the optimal operation pattern from all combinations (processes T1 to T6 in FIG. 4) according to the procedure shown in the flowchart shown in FIG. A start/stop command is given to the five blowers B1 to B5 through the output interface circuit 4 (process T7 in FIG. 4). (1) Calculation of load factor upper and lower limit values The load factor upper limit value α _H and load factor lower limit value α _L are calculated as follows from the target load factor α _dn determined by the target load factor setting circuit 7 (processing T1 ). α _H = α _dn +x α _L = α _dn −x However, x is the specified load factor value, which is the difference between the target load factor α _dn and the load factor upper and lower limit values α _H and α _L ; The controllable range of each step is defined. (2) Determining the total air volume step The load factor, which is the total air flow required value Q _SV for the maximum air flow Q _M of the current operation pattern, becomes the load factor upper limit value α _H and the load factor lower limit value α _L calculated in (1). On the other hand, if the following relationship occurs, the steps are changed (processing T
2). Q _SV ／Q _M ＞α _H +DQ or Q _SV ／Q _M ＜α _L −DQ (However, DQ is a dead zone) When determining a new step, select α _L ＜ Q _SV ／Q _M ＜ α _H from among all steps. Select all the steps that satisfy (processing T3), and if there are multiple applicable steps, select the step with the smallest deviation |Q _SV /Q _M −α _dn | between Q _SV /Q _M and the target load factor α _dn | is selected (processing T4). (3) Determination of minimum start/stop frequency pattern Select the minimum start/stop frequency pattern from all operation patterns corresponding to the step selected in (2) using a method similar to the conventional method (b) (processing T
5). (4) Determination of priority order The pattern with the highest priority order is selected from the plurality of patterns selected in (3) using a method substantially similar to the conventional method (c) (process T6). That is, the following two points are different between the number control method shown in this embodiment and the conventional method. (a) The load factor upper limit value α _H and the load factor lower limit value α _L are not fixed, but are calculated using the following formula from the target load factor α _dn and the specified load factor value x. α _H = α _dn +x α _L = α _dn −x (b) When selecting a new step, among multiple steps such that α _L < Q _dn /Q _M < α _H |Q _SV /Q _M − α The step with the minimum _dn | is now selected. Next, the control operation by such a method of controlling the number of operating vehicles will be explained in detail. The load factor upper limit value α _H and load factor lower limit value α _L in the total air volume step of the operating pattern at that time change depending on the value of the target load factor α _dn . When α _dn is large, α _L increases in accordance with α _dn , so the step is switched to a step with a smaller total air volume earlier than when α _L is fixed. Furthermore, when α _dn is small, α _H becomes smaller as α _dn , so the step is switched to a step with a larger total air volume earlier than when α _H is fixed. Next time you select a new step, α _L <
Among the steps that satisfy Q _SV /Q _M <α _H | Q _MAX /Q _SV −α _d
Since the step with the minimum _n | is selected, if α _dn is large, a step with a small total air volume is selected, and if α _dn is small, a step with a large total air volume is selected. Therefore, the larger α _dn is, the step with a smaller total air volume is operated, and the smaller α _{dn is} , the higher the total air volume is. You can specify whether to run in small steps or in small steps. In this way, depending on the value of the target load factor α _dn that can be set, it is possible to specify whether to operate in large-capacity steps or small-capacity steps, which is the basic idea of controlling the number of units, thereby reducing power consumption. It is now possible to easily specify whether to prioritize the operation or to reduce the frequency of starting and stopping by controlling the number of units, making it possible to achieve sophisticated control of the number of units with good controllability and operability. Note that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof. For example, even in processes where the capacity and number of target machines are different, the circuit and control method used in the above example can be applied as is by simply changing each data in Table 2, which improves overall reliability. is also good. Further, in the same embodiment, each circuit shown in FIG. 3 has been described as a hardware element, but it is of course possible to realize the same function with a software element of a computer. Furthermore, the load factor specified value x is the load factor upper limit value α _H ,
Although the load factor lower limit value α _L was considered to be the same for both, it is also possible to set different load factor prescribed values for each. [Effects of the Invention] According to the present invention, it is possible to preset whether to operate in steps with a large total air volume or in small steps as a whole, and to provide a method for controlling the number of units that enables advanced control and has good controllability. Can be done.

【table】

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of the configuration of a conventional number-of-units control system, FIG. 2 is a flowchart showing a control method in the same example, and FIG. 3 is the configuration of a system for controlling the number of units according to an embodiment of the present invention. Figure, 4th
The figure is a flowchart showing the control method in the same embodiment. 1...Pressure detection device, 2...Total air volume calculation circuit,
4... Input/output interface circuit, 6... Priority order determining circuit, 7... Target load factor setting circuit, 8...
...Number of units control calculation circuit, B1 to B5...Blower.

Claims (1)

[Claims] 1. When controlling the number of multiple control target machines, the output obtained by the combination of these control target machines is divided into multiple stages in advance, and all combinations belonging to the stage that satisfy the required output amount are In a method for controlling the number of operating units that selects a pattern, first a target value of the load factor is given by an operator, etc., then an upper limit value and a lower limit value are determined from this target value,
Next, candidate steps are determined from the load ratio between the current demand and the maximum capacity value of each step, and finally, the absolute value of the deviation between the initially sought target value of these steps and the current load ratio calculation value is determined. A method for controlling the number of operating vehicles, characterized in that the smallest one is selected.