JP5345816B2 - Control apparatus and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the limit of control while maintaining the total sum of manipulated variables to a value which is equal to or more than the lower limit value of the total sum of manipulated variables. <P>SOLUTION: A control device includes: PID arithmetic parts 22-1 and 22-2 for calculating manipulated variables MV1 and MV2 on the basis of a deviation between manipulated variables PV1 and PV2 and set values SP1 and SP2 of each control loop; manipulated variable total sum calculation parts 31-1 and 31-2 for calculating total sum MV_all of the manipulated variables MV1 and MV2; and manipulated variable fixing parts 32-1 and 32-2 for, when the manipulated variable total sum MV_all reaches a preliminarily specified manipulated variable total sum lower limit value, and becomes equal to or less than the lower limit value, fixing the manipulated variables MV1 and MV2 to a value based on the manipulated variables MV1 and MV2 at a point of time when the reach is generated. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a control device and a control method for a multi-loop control system including a plurality of control loops that respectively control a plurality of zones obtained by spatially dividing a control target.

  Some air conditioning systems for large or medium-scale spaces control the temperature (room temperature) of each zone by dividing the space into multiple zones and controlling the amount of air sent to each zone. . In the control system of each zone, the control amount PV is controlled as a state quantity (temperature) to be controlled, the set value SP is set as a target value for the state quantity (temperature), and the control amount PV is controlled to the set value SP. The operation amount MV is processed by the controller of each zone as a control command (air volume or valve opening that determines air volume, damper opening). As a control method at this time, a linear control method (for example, PID) is widely used.

  Due to the necessity of ventilation, the total amount of air sent to the air-conditioned space is limited to the minimum required amount. In order to secure the lower limit value (substantially, the lower limit value of the sum of the operation amounts MV) OL_all of the total air volume, the operation amount lower limit value OL of each zone is fixed to a numerical value larger than zero. For example, a mode is conceivable in which the lower limit value OL of the operation amount MV output from each controller of a plurality of divided zones is fixed uniformly at 20.0%. In this way, when the lower limit value OL of the operation amount MV is uniformly fixed at 20.0%, the operation amount MV is reduced even if it is desired to make the operation amount MV smaller than 20.0% for convenience of temperature control. Since it cannot be made smaller than the lower limit value OL, the control amount PV cannot be controlled to the set value SP. That is, as a result, the controllable temperature range is restricted.

  Conventionally, a control device disclosed in Patent Document 1 has been proposed as a technique for maintaining the controllability of each controller while limiting the sum of the operation amounts MV of a plurality of control systems. This control device can obtain good controllability for the priority controller while maintaining the sum of the operation amounts MV of the plurality of control systems below a predetermined value, and can also be applied to the non-priority controller. In this way, controllability can be maintained.

JP 2002-49401 A

  As described above, in the conventional air conditioning system, in order to secure the lower limit value OL_all of the total amount of air sent to the air-conditioning target space, when the operation amount lower limit value OL of each zone is fixed uniformly, the operation amount MV is set to the lower limit value. Since it cannot be made smaller than OL, there is a problem that a controllable temperature range is limited.

  The control device disclosed in Patent Document 1 operates an upper limit value of the operation amount MV in order to maintain the sum of the operation amounts MV of a plurality of control systems below a predetermined value, and the lower limit value of the operation amount MV. The above-mentioned problem in the conventional air conditioning system cannot be solved.

  The present invention has been made to solve the above-described problem, and controls the operation amount in each zone by being constrained by the operation amount lower limit value while maintaining the operation amount sum at a value equal to or higher than the operation amount total lower limit value. An object of the present invention is to provide a control device and a control method capable of improving the limit of the above.

The present invention relates to a control device for a multi-loop control system having a plurality of control loops for controlling a plurality of zones obtained by spatially dividing a control target, and a control amount PV for each control loop and each control loop corresponding thereto. A plurality of control operation means for calculating the operation amount for each control loop based on a deviation from the set value SP, an operation amount total calculation means for calculating the sum of the plurality of calculated operation amounts, and the operation amount total The plurality of manipulated variables so that the total manipulated variable becomes a value equal to or greater than the manipulated variable total lower limit when the predefined manipulated variable total lower limit is reached and becomes less than or equal to the lower limit. and an operation amount fixing means for fixing to a value based on the operation amount of time when the arrival occurs before Symbol plurality of control operation unit, the lower limit processing for limiting the calculated the operation amount of the operation amount lower limit value or more values Have means to do before The operation amount fixing means has reached the operation amount lower limit value used in the plurality of control calculation means when the operation amount total reaches the operation amount total lower limit value and becomes lower than the lower limit value. It is characterized in that it is fixed to a value based on the operation amount output from the control calculation means at the time.
Further, in one configuration example of the control device according to the present invention, the operation amount fixing means may include the plurality of control computations when the operation amount total reaches the operation amount total lower limit value and falls below the lower limit value. The operation amount lower limit value used in the means is fixed to the value of the operation amount output from the respective control operation means when the arrival occurs.

Further, in one configuration example of the control device of the present invention, the operation amount fixing means is OL ′ for the operation amount lower limit value used by the control calculation means of the zone to be controlled, and the operation amount output from the control calculation means. MV, when the operation amount total is MV_all and the operation amount total lower limit value is OL_all, and when the operation amount total MV_all is less than or equal to the operation amount total lower limit value OL_all, the operation amount lower limit value OL ′ is It is characterized by MV · OL_all / MV_all.
Further, in one configuration example of the control device according to the present invention, the operation amount fixing means is OL ′ for the operation amount lower limit value used by the control calculation means of the control target zone, and other zone other than the control target zone. When the sum of operation amounts is MVe, the operation amount total is MV_all, the operation amount total lower limit is OL_all, and a predetermined margin is Δ, the operation amount total MV_all is less than or equal to the operation amount total lower limit OL_all. Instead of fixing the operation amount lower limit value OL ′ when the operation amount lower limit value OL ′ is reached, when the operation amount total sum MV_all becomes equal to or less than the sum of the operation amount total lower limit value OL_all and the margin amount Δ, the operation amount lower limit value OL 'Is OL_all + Δ-MVe.
Further, in one configuration example of the control device of the present invention, the operation amount fixing means cancels the fixed state of the plurality of operation amounts when the operation amount total exceeds the operation amount total lower limit value. It is a feature.
Further, in one configuration example of the control device of the present invention, the operation amount total calculation unit adds a damping processing unit that performs a damping process to each of the plurality of operation amounts, and a plurality of operation amounts after the damping process. And adding means for calculating the total operation amount.

Further, the present invention provides a control method for a multi-loop control system including a plurality of control loops for controlling a plurality of zones obtained by spatially dividing a control target, and a control amount PV of each control loop and each of the control amounts PV corresponding thereto. A control calculation procedure for calculating an operation amount for each control loop based on a deviation from the set value SP of the control loop, an operation amount total calculation procedure for calculating a sum of the plurality of calculated operation amounts, and the operation amount total The plurality of manipulated variables so that the total manipulated variable becomes a value equal to or greater than the manipulated variable total lower limit when the predefined manipulated variable total lower limit is reached and becomes less than or equal to the lower limit. An operation amount fixing procedure for fixing the operation amount to a value based on the operation amount at the time when the arrival has occurred, and the control calculation procedure performs a lower limit process for limiting the calculated operation amount to a value equal to or greater than an operation amount lower limit value. Including In the operation amount fixing procedure, when the operation amount lower limit value used in the control calculation procedure is reached when the operation amount total reaches the operation amount total lower limit value and becomes equal to or lower than the lower limit value. The value is fixed to the value based on the operation amount output by the control calculation procedure .

  According to the present invention, when the total operation amount reaches a predetermined operation amount total lower limit value and becomes equal to or lower than the lower limit value, each operation amount is set to a value based on the operation amount at the time when the arrival has occurred. By fixing, the restriction of the operation amount lower limit value of each zone can be relaxed while maintaining the operation amount sum above the operation amount sum lower limit value, and the operation amount of each zone is restricted by the operation amount lower limit value. The limit of the control by being done can be improved.

[Principle of the Invention]
In an air conditioning system that controls the temperature of each zone by dividing the space into a plurality of zones and controlling the amount of air sent to each zone, in order to secure the lower limit value OL_all of the sum of the air volumes (sum of the operation amounts MV) The lower limit value OL of the operation amount MV output from each controller for each zone does not need to be fixed in advance. That is, if the total amount of airflow (total amount of operation amount MV) is constantly monitored and the total amount of airflow reaches the lower limit value OL_all and the operation amount MV of each controller is not lowered below the value at that time, the lower limit value The inventor noticed that OL_all could be secured.

  FIG. 1 is a flowchart for explaining the principle of the present invention. When the sum of the air volumes (sum of the manipulated variables MV) has not reached the lower limit value OL_all (NO in step S1 in FIG. 1), the manipulated variable lower limit value OL of each zone is required at the minimum for convenience of each zone. A value is set (step S2). For example, if OL = 0, there is no restriction.

  On the other hand, when the total air volume (total operation amount MV) decreases and reaches the lower limit value OL_all (YES in step S1), the operation amount MV of each zone is fixed to the value at this arrival point (step S3). . At this time, strictly speaking, it is necessary to devise a method such as fixing the operation amount MV of the control cycle immediately before the lowering value OL_all so that the total air volume does not fall below the lower limit value OL_all. In this fixed state, it is preferable not to fix the control calculation but to fix the operation amount lower limit value OL of each zone. That is, the controller calculates the operation amount MV regardless of the operation amount lower limit value OL. The operation amount MV is limited by the operation amount lower limit value OL when the operation amount MV is output from the controller to the outside.

  As a result of executing the control with the manipulated variable lower limit value OL fixed, if the sum of the air volumes (sum of manipulated variables MV) is larger than the lower limit value OL_all and there is a margin (YES in step S4). ), The fixed state of the operation amount lower limit value OL of each zone is released (step S5).

  In the case of the above principle, the individual lower limit operation amount MV at the lowest sum is substantially unconstrained. That is, even when the individual lower limit manipulated variable MV at the lowest sum is continuously output, the probability that the effect of controlling the control amount PV to the set value SP is greatly sacrificed is Will be reduced.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing the configuration of the air conditioning system according to the first embodiment of the present invention.
Reference numeral 1 denotes a space to be subjected to air conditioning control, Z1 and Z2 are two zones obtained by dividing the space 1, 2-1 and 2-2 are controllers that perform temperature control for each of the zones Z1 and Z2, and 3 is an operation amount MV1 and MV2. , 4-1 and 4-2 are sensors for measuring the control amounts PV1 and PV2 of the zones Z1 and Z2, and 5 is a heat source for supplying cold air to the zones Z1 and Z2. System 6-1 and 6-2 are air volume regulators for adjusting the volume of cool and warm air supplied to the zones Z1 and Z2, and 7-1 and 7-2 are cool and warm air outlets of the zones Z1 and Z2.

The heat source system 5 includes, for example, a heat source that supplies cold / hot water, a coil that cools or heats air using the cold / hot water supplied from the heat source, a blower that sends out the cooled or heated air, and the like.
In the present embodiment, the medium-sized space 1 is divided into two zones Z1 and Z2 for temperature control. In this case, a normal single loop control system is constituted by two loops.

  FIG. 3 shows a configuration of a control device used in the air conditioning system of the present embodiment. The control device includes controllers 2-1 and 2-2, which are components for configuring a single loop control system, and a cooperative operation calculation unit 3.

  For example, the controller 2-1 inputs a set value SP input unit 20-1 that inputs a set value SP1 set by a resident of the zone Z1, and a control amount PV1 of the zone Z1 measured by the sensor 4-1. An amount PV input unit 21-1, a PID operation unit 22-1 serving as a control operation unit for calculating the operation amount MV1 based on the set value SP1 and the control amount PV1, and an operation amount MV1 for the air volume adjuster 6 in the zone Z1. 1 and an operation amount MV output unit 23-1 that outputs to the cooperative operation calculation unit 3.

  Similarly, the controller 2-2 inputs the set value SP input unit 20-2 for inputting the set value SP2 set by the resident of the zone Z2, and the control amount PV2 of the zone Z2 measured by the sensor 4-2. Control amount PV input unit 21-2 to perform, PID calculation unit 22-2 serving as a control calculation means for calculating the operation amount MV2 based on the set value SP2 and the control amount PV2, and the operation amount MV2 to the air volume adjuster in the zone Z2. 6-2 and an operation amount MV output unit 23-2 that outputs to the cooperative operation calculation unit 3.

  The cooperative operation calculation unit 3 includes other operation amount input units 30-1 and 30-2 that receive operation amounts of zones other than the control target zone, and an operation amount total calculation unit 31- that calculates the sum of operation amounts. 1 and 31-2 and operation amount fixing units 32-1 and 32-2 for performing an operation amount fixing process and a fixing release process based on the operation amount total are provided for the zones Z1 and Z2, respectively.

  FIG. 4 shows a block diagram of a control system in the present embodiment. P1 is a control target of the zone Z1, P2 is a control target of the zone Z2, and a feedback control system is formed for each of the zones Z1 and Z2 together with the PID calculation units 22-1 and 22-2. That is, a feedback control system including the control target P1 and the PID calculation unit 22-1 is formed in the zone Z1, and a feedback control system including the control target P2 and the PID calculation unit 22-2 is formed in the zone Z2.

  SP1 is a set value of the zone Z1, PV1 is a control amount of the zone Z1, and both are temperatures in this embodiment. Similarly, SP2 is a set value of the zone Z2, PV2 is a control amount of the zone Z2, and both are temperatures in this embodiment. MV1 is the operation amount of zone 1 calculated by the PID calculation unit 22-1, and MV2 is the operation amount of zone 2 calculated by the PID calculation unit 22-2.

  The operation amount total calculation units 31-1 and 31-2 and the operation amount fixing units 32-1 and 32-2 calculate the operation amount total MV_all and compare the operation amount total MV_all with the lower limit value OL_all. Thus, a cooperative control system for appropriately fixing the operation amount lower limit value OL is configured.

FIG. 5 shows a block diagram of a suitable control system in the present embodiment. FIG. 5 shows a more preferable and detailed configuration of the control system shown in FIG.
The damping processing units 310 and 311 are components for reducing high-frequency fluctuations in the operation amounts MV1 and MV2. The damping processing units 310 and 311 may be realized by, for example, a low-pass filter having a first-order delay time delay characteristic. When the time constant of the damping process in the zone Z1 is T1, the time constant of the damping process in the zone Z2 is T2, and the Laplace operator is s, the transfer function of the damping processing unit 310 is 1 / (1 + T1s), and the transmission of the damping processing unit 311 The function is 1 / (1 + T2s).

The adder 312 calculates an operation amount total MV_all, which is the sum of the operation amounts MV1 and MV2 after the damping process, as in the following equation.
MV_all = MV1 + MV2 (1)

The operation amount fixing units 32-1 and 32-2 are components for fixing the operation amount lower limit value OL of each of the controllers 2-1 and 2-2 including the margin amount Δ that can be appropriately set by the operator. It is. Specifically, the operation amount fixing units 32-1 and 32-2 execute the following expressions.
If MV_all ≦ OL_all + Δ
Then OL1 '← MV1, OL2' ← MV2
Else OL1 ′ ← OL1, OL2 ′ ← OL2 (2)

  In Expression (2), OL_all is a lower limit value of the sum total of the manipulated variables MV corresponding to the sum of the minimum air volumes required for ventilation of the space 1, and is a predetermined constant value. OL1 ′ and OL2 ′ are the operation amount lower limit values actually used in the controllers 2-1 and 2-2 of the zones Z1 and Z2, respectively. OL1 and OL2 are at least required for the convenience of the zones Z1 and Z2, respectively. The operation amount lower limit value defined in advance as the operation amount. For example, if OL1 = OL2 = 0%, the operation amounts MV1 and MV2 in a situation where the operation amount lower limit value is not fixed are completely unconstrained.

  Expression (2) indicates that when the total operation amount MV_all is equal to or less than the sum of the lower limit value OL_all and the margin amount Δ, the operation amount MV1 in the zone Z1 is used as the operation amount lower limit value actually used in the controller 2-1 in the zone Z1. This means that the operation amount MV2 of the zone Z2 is set to the operation amount lower limit value OL2 ′ actually used in the controller 2-2 of the zone Z2, and the operation amount lower limit values OL1 ′ and OL2 ′ are fixed. ing. Further, when the total operation amount MV_all is larger than the sum of the lower limit value OL_all and the allowance amount Δ, the expression (2) indicates that the operation amount lower limit value OL1 actually used in the zone Z1 is actually used. It means that the operation amount lower limit value OL2 defined in advance in the zone Z2 is set as the operation amount lower limit value OL2 ′ that is actually used, as well as OL1 ′.

When there is a concern that the operation amount total MV_all is significantly lower than the lower limit value OL_all due to the newly calculated operation amounts MV1 and MV2, the operation amount fixing units 32-1 and 32-2 may be replaced with Expression (2). It is preferable to perform the following treatment.
If MV_all ≦ OL_all + Δ
Then OL1 '← MV1OL_all / MV_all
, OL2 '← MV2OL_all / MV_all
Else OL1 ′ ← OL1, OL2 ′ ← OL2 (3)

  In both the processes of Expressions (2) and (3), the processes after “Else” are the operation amount lower limit value when the operation amount total MV_all becomes larger than the sum of the lower limit value OL_all and the margin amount Δ. This means that the fixing of OL1 ′ and OL2 ′ is released. That is, since the control calculation (PID calculation) is not fixed, when the total operation amount MV_all becomes more than the lower limit value OL_all, the fixed state of the operation amount lower limit values OL1 ′ and OL2 ′ of each zone is Canceled.

Hereinafter, the operation of the control device of the present embodiment will be described. FIG. 6 is a flowchart showing the operation of the control device.
The set value SP1 is set, for example, by a resident in the zone Z1, and is input to the PID calculation unit 22-1 via the set value SP input unit 20-1 of the controller 2-1 (step S100). The set value SP2 is set by, for example, a resident in the zone Z2, and is input to the PID calculation unit 22-2 via the set value SP input unit 20-2 of the controller 2-2 (step S101).

  The control amount PV1 is measured by the sensor 4-1, and is input to the PID calculation unit 22-1 via the control amount PV input unit 21-1 of the controller 2-1 (step S102). The control amount PV2 is measured by the sensor 4-2, and is input to the PID calculation unit 22-2 via the control amount PV input unit 21-2 of the controller 2-2 (step S103).

The PID calculation unit 22-1 calculates a manipulated variable MV1 by performing a PID control calculation such as the following equation based on the set value SP1 and the control amount PV1 (step S104), and the PID calculation unit 22-2 sets the setting. An operation amount MV2 is calculated based on the value SP2 and the control amount PV2 (step S105).
MV1 = Kg1 {1+ (1 / Ti1s) + Td1s} (SP1-PV1)
... (4)
MV2 = Kg2 {1+ (1 / Ti2s) + Td2s} (SP2-PV2)
... (5)

In Expressions (4) and (5), Kg1 and Kg2 are proportional gains, Ti1 and Ti2 are integration times, and Td1 and Td2 are differentiation times.
Note that the proportional gains Kg1, Kg2 are set to negative values during cooling, and the proportional gains Kg1, Kg2 are set to positive values during heating.

Furthermore, the PID calculation unit 22-1 performs upper and lower limit processing of the operation amount MV1 as in the following expression when the operation amount MV1 is output.
IF MV1> OH1 THEN MV1 = OH1 (6)
IF MV1 <OL1 ′ THEN MV1 = OL1 ′ (7)
That is, when the operation amount MV1 is larger than the preset operation amount upper limit value OH1, the PID calculation unit 22-1 outputs the operation amount MV1 = OH1 and the operation amount MV1 is output from the operation amount fixing unit 32-1. When the operation amount is lower than the lower limit value OL1 ′, the operation amount is output as MV1 = OL1 ′.

Similarly, when outputting the operation amount MV2, the PID calculation unit 22-2 performs upper and lower limit processing of the operation amount MV2 as in the following expression.
IF MV2> OH2 THEN MV2 = OH2 (8)
IF MV2 <OL2 ′ THEN MV2 = OL2 ′ (9)
OH2 is a preset operation amount upper limit value, and OL2 'is an operation amount lower limit value output from the operation amount fixing unit 32-2.

  The manipulated variable MV output units 23-1 and 23-2 output the manipulated variables MV1 and MV2 output from the PID calculating units 22-1 and 22-2 to the air volume adjusters 6-1 and 6-2, respectively. The result is output to the operation calculation unit 3.

  The total operation amount calculation unit 31-1 of the cooperative operation calculation unit 3 receives the operation amount MV1 output from the controller 2-1 and receives the operation amount MV2 output from the controller 2-2 from the other operation amount input unit 30. Receive via -1. The operation amount total calculation unit 31-2 receives the operation amount MV2 output from the controller 2-2 and also receives the operation amount MV1 output from the controller 2-1 via the other all operation amount input unit 30-2. .

  The damping processing units 310 and 311 in the operation amount total calculation unit 31-1 perform damping processing on the operation amounts MV1 and MV2, respectively (step S106). Similarly, the damping processing units 310 and 311 in the operation amount total calculation unit 31-2. 311 performs a damping process on the operation amounts MV1 and MV2 (step S107).

  Subsequently, the adding unit 312 in the operation amount total calculation unit 31-1 calculates the operation amount total MV_all from the operation amounts MV1 and MV2 after the damping process as shown in Expression (1) (step S108), and similarly. The adding unit 312 in the operation amount total calculation unit 31-2 calculates the operation amount total MV_all (step S109).

  Next, the operation amount fixing unit 32-1 determines whether or not the operation amount total MV_all is equal to or less than the sum of the lower limit value OL_all and the margin amount Δ (step S110). Similarly, the operation amount fixing unit 32-2 It is determined whether the total amount MV_all is less than or equal to the sum of the lower limit value OL_all and the margin amount Δ (step S111).

  When the total operation amount MV_all is greater than the sum of the lower limit value OL_all and the margin amount Δ, the operation amount fixing unit 32-1 operates the lower limit value of the operation amount that is actually used in the zone Z1 predetermined operation amount lower limit value OL1. This operation amount lower limit value OL1 ′ is output as OL1 ′ to the PID calculation unit 22-1 (step S112). When the total operation amount MV_all is larger than the sum of the lower limit value OL_all and the margin amount Δ, the operation amount fixing unit 32-2 operates the lower limit value of the operation amount that is actually used in the predetermined operation amount lower limit value OL2 of the zone Z2. This operation amount lower limit value OL2 ′ is output as OL2 ′ to the PID calculation unit 22-2 (step S113).

  Further, when the total operation amount MV_all is equal to or less than the sum of the lower limit value OL_all and the margin amount Δ, the operation amount fixing unit 32-1 sets the operation amount MV1 of the zone Z1 as the operation amount lower limit value OL1 ′ and sets the operation amount lower limit value. OL1 'is output to the PID calculating part 22-1 (step S114). When the total operation amount MV_all is equal to or less than the sum of the lower limit value OL_all and the margin amount Δ, the operation amount fixing unit 32-2 sets the operation amount MV2 of the zone Z2 as the operation amount lower limit value OL2 ′ and sets the operation amount lower limit value OL2 ′. Is output to the PID calculation unit 22-2 (step S115).

  The processes in steps S100 to S115 as described above are repeatedly executed for each control cycle until the end of control is instructed by an operator of the air conditioning system (YES in step S116), for example.

  FIG. 7 is a diagram showing numerical examples at the time of cooling of the conventional air conditioning system and the air conditioning system of the present embodiment. In FIGS. 7A, 7B, and 7C, it is assumed that the lower limit value OL_all of the total operation amount defined in advance is 40.0%. In the present embodiment, the operation amount lower limit values OL1 and OL2 defined in advance are both 0%.

  FIG. 7A shows the case of a conventional air conditioning system. Here, the set value SP1 of the zone Z1 and the set value SP2 of the zone Z2 are both 25.0 ° C., and the operation amount lower limit value OL1 of the zone Z1 and the operation amount lower limit value OL2 of the zone Z2 are both 20.0%. And In order to control the control amount PV1 of the zone Z1 to 25.0 ° C., the operation amount MV1 originally necessary is 25.0%, and originally necessary to control the control amount PV2 of the zone Z2 to 25.0 ° C. If the manipulated variable MV2 is 18.0%, then (MV1 + MV2)> OL_all, and the total manipulated variable MV has a margin of 3.0%. However, since the operation amount lower limit value OL2 for the zone Z2 is 20.0%, the operation amount MV2 is limited to 20.0%, that is, by performing cooling more than necessary, the control amount PV2 of the zone Z2 is For example, the temperature is 24.3 ° C., which is shifted from the set value SP2. Thus, in the conventional air conditioning system, the controllable temperature range is restricted.

  On the other hand, when this embodiment is applied to the situation shown in FIG. 7A, if the operation amount MV1 of the zone Z1 is 25.0% and the operation amount MV2 of the zone Z2 is 18.0%, MV_all> OL_all + Δ (the margin amount Δ is set to 0% here), and the total of the manipulated variables MV has a margin of 3.0%. Therefore, as shown in FIG. 7B, the manipulated variable lower limit value OL1 ′ remains OL1 = 0%, and the manipulated variable lower limit value OL2 ′ remains OL2 = 0%, so that MV1 = 25.0%. , MV2 = 18.0% is output without restriction, and the control amount PV1 of the zone Z1 and the control amount PV2 of the zone Z2 are both controlled to 25.0 ° C.

  From the state of FIG. 7B, when the external condition changes and the originally required operation amount decreases, the operation amount total MV_all coincides with the sum of the lower limit value OL_all and the margin amount Δ, and the operation amount MV1, at this time The manipulated variable lower limit values OL1 ′ and OL2 ′ are fixed to the value of MV2. In the example of FIG. 7C, OL1 '= MV1 = 23.5% and OL2' = MV2 = 16.5%. In this case, for example, the control amount PV1 of the zone Z1 and the control amount PV2 of the zone Z2 are both 24.9 ° C. and slightly deviate from the settings SP1 and SP2, so that the controllability is sacrificed. It can be seen that the probability that the controllability is greatly sacrificed is reduced.

  Thus, in the present embodiment, it is possible to relax the restriction on the operation amount lower limit value of each zone while maintaining the operation amount sum MV_all at a value equal to or greater than the operation amount total lower limit value OL_all. Is limited by the lower limit of the manipulated variable, so that the control limit can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 8 is a block diagram showing a configuration of an air conditioning system according to the second embodiment of the present invention.
1a is a space subject to air conditioning control, Z1 to Z6 are six zones obtained by dividing the space 1a, 2-1 to 2-6 are controllers that perform temperature control for each of the zones Z1 to Z6, 3a is a cooperative operation calculation unit, 4-1 to 4-6 are sensors for measuring the control amounts PV1 to PV6 of the zones Z1 to Z6, 5 is a heat source system for supplying the warm air to the zones Z1 to Z6, and 6-1 to 6-6 are the zones Z1 to Z6. The air volume regulators 7-1 to 7-6 for adjusting the air volume of the cool and warm air supplied to the air are outlets for the cool and warm air in the zones Z1 to Z6.

In the present embodiment, the large-scale space 1a is divided into six zones Z1 to Z6 for temperature control. In this case, a normal single-loop control system is configured with six loops.
FIG. 9 shows a configuration of a control device used in the air conditioning system of the present embodiment. The control device includes controllers 2-1 to 2-6 and a cooperative operation calculation unit 3a.

  The controllers 2-1 to 2-6 include set value SP input units 20-1 to 20-6, control amount PV input units 21-1 to 21-6, PID calculation units 22-1 to 22-6, The manipulated variable MV output units 23-1 to 23-6 are provided for the zones Z1 to Z6, respectively.

  The cooperative operation calculation unit 3a includes other operation amount input units 30a-1 to 30a-6, operation amount total calculation units 31a-1 to 31a-6, and operation amount fixing units 32-1 to 32-6. Provided for each of the zones Z1 to Z6.

  FIG. 10 shows a block diagram of a control system in the present embodiment. Similar to the first embodiment, a feedback control system including the control target P1 and the PID calculation unit 22-1 is formed in the zone Z1. The same applies to the other zones Z2 to Z6. In FIG. 10, only the control system of the zone Z1 is shown, and the description of the control systems of the other zones Z2 to Z6 is omitted.

MVe1 represents the sum of the operation amounts MV2 to MV6 of the zones Z2 to Z6 other than the zone Z1.
The operation amount total calculation unit 31a-1 and the operation amount fixing unit 32-1 calculate the operation amount total MV_all, compare the operation amount total MV_all with the lower limit value OL_all, and appropriately set the operation amount lower limit value OL. The fixed cooperative control system is configured.

FIG. 11 shows a block diagram of a suitable control system in the present embodiment. FIG. 11 shows a more preferable and detailed configuration of the control system shown in FIG.
The configuration and operation of the damping processing unit 310 in the operation amount total calculation unit 31a-1 are the same as those in the first embodiment.

The addition unit 313 in the operation amount total calculation unit 31a-1 calculates another total operation amount MVe1 that is the sum of the operation amounts MV2 to MV6 of the zones Z2 to Z6 other than the zone Z1 as in the following equation.
MVe1 = MV2 + MV3 + MV4 + MV5 + MV6 (10)

  The damping processing unit 314 is a component for reducing high-frequency fluctuations of the other total operation amount sum MVe1. The damping processing unit 314 may be realized by a low-pass filter having a time delay characteristic of a first order delay, for example. When the time constant of the damping process of the other total operation amount sum MVe1 is Te1, the transfer function of the damping processing unit 314 is 1 / (1 + Te1s).

The adder 312a calculates an operation amount total MV_all, which is the sum of the operation amounts MV1 and MVe1 after the damping process, as in the following equation.
MV_all = MV1 + MVe1 (11)

Similar to the first embodiment, the operation amount fixing unit 32-1 is configured to fix the operation amount lower limit value OL of the controller 2-1 including a margin amount Δ that can be set as appropriate by the operator. Is an element. Specifically, the operation amount fixing unit 32-1 executes the following expression.
If MV_all ≦ OL_all + Δ
Then OL1 '← MV1
Else OL1 '← OL1 (12)

  In Expression (12), OL_all is a lower limit value of the sum total of the manipulated variables MV corresponding to the sum of the minimum air volumes necessary for ventilation of the space 1, and is a predetermined constant value. OL1 'is an operation amount lower limit value that is actually used in the controller 2-1 of the zone Z1, and OL1 is an operation amount lower limit value that is defined in advance as an operation amount that is minimum required for the convenience of the zone Z1. For example, if OL1 = 0%, the operation amount MV1 in a situation where the operation amount lower limit is not fixed is completely unconstrained.

  Expression (12) means that the operation amount total MV_all is determined when the control calculation (PID calculation) of the controller 2-1 in the zone Z1 is executed. When the lower limit value OL_all is less than or equal to the sum of the margin amount Δ, the operation amount lower limit values OL1 ′ to OL6 ′ of all the zones Z1 to Z6 may be fixed to the operation amounts MV1 to MV6, respectively. .

When there is a concern that the total operation amount MV_all is greatly below the lower limit value OL_all due to the newly calculated operation amount MV1, the operation amount fixing unit 32-1 performs the following processing instead of the equation (12). It is preferable to carry out.
If MV_all ≦ OL_all + Δ
Then OL1 ′ ← OL_all + Δ−MVe1
Else OL1 '← OL1 (13)

Although the processing of the zone Z1 has been described so far, the same processing may be performed for other zones.
Note that the operation amount total MV_all may be determined only once after the control calculation (PID calculation) of the controllers 2-1 to 2-6 in all the zones Z1 to Z6 in one control cycle. When the newly calculated operation amounts MV1, MV2,..., MV6 are concerned that the operation amount total MV_all is greatly below the lower limit value OL_all, the operation amount fixing units 32-1 to 32-6 are It is preferable to perform the following processing instead of the equation (12).
If MV_all ≦ OL_all + Δ
Then OL1 '← MV1OL_all / MV_all
, OL2 '← MV2OL_all / MV_all, ...
, OL6 '← MV6OL_all / MV_all
Else OL1 ′ ← OL1, OL2 ′ ← OL2,..., OL6 ′ ← OL6
(14)

  In any of the processing of Expression (12), Expression (13), and Expression (14), the processing after “Else” is performed when the operation amount sum MV_all becomes larger than the sum of the lower limit value OL_all and the margin amount Δ. This means that the fixed operation amount lower limit values OL1 ′ to OL6 ′ are released. That is, since the control calculation (PID calculation) is not fixed, when the total operation amount MV_all becomes more than the lower limit value OL_all, the fixed state of the operation amount lower limit values OL1 ′ to OL6 ′ of each zone is Canceled.

Hereinafter, the operation of the control device of the present embodiment will be described. FIG. 12 is a flowchart showing the operation of the control device. In FIG. 12, only the processing of zones Z1 and Z2 is described for easy description.
The processing of steps S200 to S205 is the same as steps S100 to S105 of the first embodiment.

The operation amount total calculation unit 31a-1 of the cooperative operation calculation unit 3a receives the operation amount MV1 output from the controller 2-1, and the operation amounts MV2 to MV6 output from the other controllers 2-2 to 2-6. Are received via the other total operation amount input unit 30a-1. The operation amount total calculation unit 31a-2 receives the operation amount MV2 output from the controller 2-2, and also operates the operation amounts MV1, MV3 to MV6 output from the other controllers 2-1, 2-3 to 2-6. Are received via the other operation amount input unit 30a-2.
The damping processing unit 310 in the operation amount total calculation units 31a-1 and 31a-2 performs damping processing on the operation amounts MV1 and MV2, respectively (steps S206 and S207).

The addition unit 313 in the operation amount total calculation unit 31a-1 calculates another total operation amount MVe1 that is the sum of the operation amounts MV2 to MV6 of the zones Z2 to Z6 other than the zone Z1 as in Expression (10). (Step S208). The addition unit 313 in the operation amount total calculation unit 31a-2 calculates the other total operation amount sum MVe2 that is the sum of the operation amounts MV1 and MV3 to MV6 of the zones Z1, Z3 to Z6 other than the zone Z2 as follows: (Step S209).
MVe2 = MV1 + MV3 + MV4 + MV5 + MV6 (15)

The damping processing unit 314 in the operation amount total calculation units 31a-1 and 31a-2 performs damping processing on the other total operation amount sums MVe1 and MVe2 respectively (steps S210 and S211).
The addition unit 312a in the operation amount total calculation unit 31a-1 calculates the operation amount total MV_all as shown in Expression (11) from the operation amounts MV1 and MVe1 after the damping process (step S212). The addition unit 312a in the operation amount total calculation unit 31a-2 calculates the operation amount total MV_all from the operation amounts MV2 and MVe2 after the damping process as shown in the following equation (step S213).
MV_all = MV2 + MVe2 (16)

The processing of steps S214 to S219 is the same as steps S110 to S115 of the first embodiment.
The processes in steps S200 to S219 as described above are repeatedly executed for each control cycle until an end of control is instructed by an operator of the air conditioning system (YES in step S220), for example. In FIG. 12, the processing of the zones Z1 and Z2 has been described, but the same processing may be performed for the other zones.
Thus, even when the space or heating area is divided into two or more zones, the same effects as those of the first embodiment can be obtained.

  In the first and second embodiments, the most widely used PID is practically preferable as the controller control algorithm, but IMC (Internal Model Control) or SAC (Simple Adaptive Control) is practically preferable. It may be.

  In addition, the controllers 2-1 to 2-6 and the cooperative operation calculation units 3 and 3a described in the first and second embodiments are provided with a computer having a CPU, a storage device, and an interface, and hardware resources thereof. It can be realized by a program to be controlled. The CPU executes the processing described in the first and second embodiments in accordance with a program stored in the storage device.

  The present invention can be applied to a multi-loop control device.

It is a flowchart for demonstrating the principle of this invention. It is a block diagram which shows the structure of the air conditioning system which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the control apparatus used with the air conditioning system which concerns on the 1st Embodiment of this invention. It is a block diagram of the control system in the 1st Embodiment of this invention. It is a block diagram of the suitable control system in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the control apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the numerical example at the time of air_conditioning | cooling of the conventional air conditioning system and the air conditioning system which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the air conditioning system which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the control apparatus used with the air conditioning system which concerns on the 2nd Embodiment of this invention. It is a block diagram of the control system in the 2nd Embodiment of this invention. It is a block diagram of the suitable control system in the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the control apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1a ... Space, 2-1 to 2-6 ... Controller, 3, 3a ... Cooperation operation calculating part, 4-1 to 4-6 ... Sensor, 5 ... Heat source system, 6-1 to 6-6 ... Air volume adjustment , 7-1 to 7-6 ... cold / hot air outlet, 20-1 to 20-6 ... set value SP input section, 211-1 to 21-6 ... control amount PV input section, 22-1 to 22-6 ... PID operation unit, 23-1 to 23-6 ... operation amount MV output unit, 30-1, 30-2, 30a-1 to 30a-6 ... all other operation amount input units, 31-1, 31-2, 31a -1 to 31a-6 ... operation amount total calculation unit, 32-1 to 32-6 ... operation amount fixing unit, 310, 311, 314 ... damping processing unit, 312, 312a, 313 ... addition unit, Z1, Z2 ... zone .

Claims (10)

In a control device of a multi-loop control system including a plurality of control loops for controlling a plurality of zones obtained by spatially dividing a control target,
A plurality of control calculation means for calculating an operation amount for each control loop based on a deviation between a control amount PV of each control loop and a setting value SP of each control loop corresponding thereto;
An operation amount total calculating means for calculating the sum of the plurality of calculated operation amounts;
When the total operation amount reaches a predetermined operation amount total lower limit value and becomes equal to or lower than the lower limit value, the plurality of operation amounts total is set to a value equal to or larger than the operation amount total lower limit value. An operation amount fixing means for fixing the operation amount to a value based on the operation amount at the time when the arrival has occurred ;
The plurality of control calculation means includes means for performing a lower limit process for limiting the calculated operation amount to a value equal to or greater than an operation amount lower limit value,
The manipulated variable fixing means reaches the manipulated variable lower limit value used in the plurality of control calculation means when the manipulated variable sum reaches the manipulated variable total lower limit value and becomes less than or equal to the lower limit value. The control device is characterized in that it is fixed to a value based on the operation amount output from the control calculation means at the time . The control device according to claim 1 ,
The manipulated variable fixing means reaches the manipulated variable lower limit value used in the plurality of control calculation means when the manipulated variable sum reaches the manipulated variable total lower limit value and becomes less than or equal to the lower limit value. The control device is characterized in that it is fixed to the value of the operation amount output from each control calculation means at the time. The control device according to claim 1 ,
The operation amount fixing means is OL ′ for the operation amount lower limit value used by the control calculation means for the control target zone, MV for the operation amount output from the control calculation means, MV_all for the operation amount total, and the operation amount total. When the lower limit value is OL_all, when the operation amount total MV_all becomes equal to or less than the operation amount total lower limit value OL_all, the operation amount lower limit value OL ′ is set to MV · OL_all / MV_all. apparatus. The control device according to claim 1 ,
The operation amount fixing means is OL ′ for the operation amount lower limit value used by the control calculation means for the control target zone, MVe for the sum of operation amounts of other zones other than the zone to be controlled, and MV_all for the total operation amount. When the total manipulated variable lower limit value is OL_all and the predetermined margin is Δ, the manipulated variable lower limit value OL ′ is fixed when the manipulated variable sum MV_all is less than or equal to the manipulated variable total lower limit value OL_all. Instead, when the operation amount total MV_all becomes equal to or less than the sum of the operation amount total lower limit value OL_all and the margin amount Δ, the operation amount lower limit value OL ′ is set to OL_all + Δ−MVe. Control device. The control device according to any one of claims 1 to 4 ,
The operation amount fixing means releases the fixed state of the plurality of operation amounts when the operation amount total exceeds the operation amount total lower limit value. In a control method of a multi-loop control system including a plurality of control loops for controlling a plurality of zones obtained by spatially dividing a control target,
A control calculation procedure for calculating an operation amount for each control loop based on a deviation between a control amount PV of each control loop and a corresponding set value SP of each control loop;
An operation amount total calculating procedure for calculating a sum of the plurality of calculated operation amounts;
When the total operation amount reaches a predetermined operation amount total lower limit value and becomes equal to or lower than the lower limit value, the plurality of operation amounts total is set to a value equal to or larger than the operation amount total lower limit value. An operation amount fixing procedure for fixing the operation amount to a value based on the operation amount at the time when the arrival occurs ,
The control calculation procedure includes a process of performing a lower limit process for limiting the calculated operation amount to a value equal to or greater than an operation amount lower limit value.
In the operation amount fixing procedure, when the operation amount lower limit value used in the control calculation procedure is reached when the operation amount total reaches the operation amount total lower limit value and becomes equal to or lower than the lower limit value. A control method characterized in that the value is fixed to a value based on an operation amount output by a control calculation procedure . The control method according to claim 6 , wherein
In the operation amount fixing procedure, when the operation amount total reaches the operation amount total lower limit value and becomes equal to or lower than the lower limit value, a plurality of operation amount lower limit values used in the control calculation procedure are reached. The control method is characterized in that the value of each manipulated variable that is output by the control calculation procedure at a certain point is fixed. The control method according to claim 6 , wherein
In the operation amount fixing procedure, the operation amount lower limit value used in the control calculation procedure of the control target zone is OL ′, the operation amount output in the control calculation procedure is MV, the operation amount total is MV_all, and the operation amount total is When the lower limit value is OL_all, when the operation amount total MV_all becomes equal to or less than the operation amount total lower limit value OL_all, the operation amount lower limit value OL ′ is set to MV · OL_all / MV_all. Method. The control method according to claim 6 , wherein
In the operation amount fixing procedure, the operation amount lower limit value used in the control calculation procedure of the control target zone is OL ′, the sum of operation amounts of other zones other than the control target zone is MVe, and the operation amount total is MV_all. When the total manipulated variable lower limit value is OL_all and the predetermined margin is Δ, the manipulated variable lower limit value OL ′ is fixed when the manipulated variable sum MV_all is less than or equal to the manipulated variable total lower limit value OL_all. Instead, when the operation amount total MV_all becomes equal to or less than the sum of the operation amount total lower limit value OL_all and the margin amount Δ, the operation amount lower limit value OL ′ is set to OL_all + Δ−MVe. Control method. The control method according to any one of claims 6 to 9 ,
The operation amount fixing procedure is characterized in that the fixed state of the plurality of operation amounts is released when the operation amount total exceeds the operation amount total lower limit value.

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