JPH05324005A - Command ff/fb controller - Google Patents

Abstract

PURPOSE:To improve the controllability, to prevent a reset windup, and to obtain balanceless and bumpless operation at the time of gain correction and automatic-manual switching. CONSTITUTION:A command FF control part 20 and a speed type two-degree-of- freedom PI control part 30 are combined with each other and the PI control part is provided with a switch part 35 on the output side of an arithmetic means 34 in addition to a command filter means 31 which gives a two degree of freedom to P operation while speed type P control arithmetic 33 and speed type I control arithmetic 34 are separated. Then FB control and FF control are put together in the form of speed type signals and converted into a position control signal, which is passed through an upper/lower-limit limiting means 42 to obtain an operation signal. At this time, a deviation deciding means 44 decides whether or not there is a deviation from a limited value from the input/ output difference of the upper/lower-limit limiting means and decides the variation state of a position type control signal by integral operation from the signs of the decision signal and the output of an I control arithmetic means, thereby performing and stopping the integral operation by turning ON and OFF a switch means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a combined target of target value FF control and FB control used in a boiler steam flow rate control device for a boiler load distribution control system, a total heat amount control device for a multi-fuel combustion system, and the like. Value FF / FB controller.

[0002]

2. Description of the Related Art A control device of this type is often applied mainly to a primary control loop of a cascade control system in which a target value and a manipulated variable are both represented by the same or different industrial units. Has a configuration in which the target value is directly FF controlled, and the FB control is a configuration in which the FF control amount is corrected and controlled within a limited range.

Typical applications of such a technique include, for example, a boiler steam flow controller in a boiler load distribution system and a total heat quantity controller for a multi-fuel combustion system.

Meanwhile, the conventional boiler load distribution system includes a plurality of boiler 2 _1, 2 ₂ for the heat supply pipe 1 as shown in FIG. 5, ... are connected in parallel, these boilers 2 _1,
2 ₂ , ... The steam flow rates PV ₁ , PV ₂ , ... Detected by the output-side steam flow rate detectors 3, ₁ , 3 ₂ , ... Are introduced into the adding means 4, and the total steam flow rate and steam pressure obtained here are obtained. The pressure adjusting output signal of the adjusting device 5 is added by the adding means 6.
Then, the load distribution ratios α ₁ and α are added to the added signal, respectively.
_2, the target value of each allocation signal multiplied by ... SV _1, SV _2, ...
Is introduced into each target value FF / FB control device 7 ₁ , 7 ₂ , ....

Here, for example, one controller 7 (=
7 ₁ ), as shown in FIG. 6, the target value SV _n (SV ₁ ) is multiplied by the FF control gain K (K is usually close to ₁ ) in the coefficient means 11 to obtain the basic manipulated variable K · SV _n , In addition, the target value SV _n and the steam flow rate PV _n (= PV ₁ )
It is led to the D controller 12, and the deviation calculating means 13 determines the deviation e _n between the signals SV _n and PV _n . further,
In the lower speed type PID adjustment calculation means 14, the deviation e _n
Described below on the basis of the calculation, i.e. _{△ MV n = K p {(} e n -e n-1) + (△ t / T I) · e n + (T D / △ t) · (e n -2e n _-1 + e _n-2 )} (1) The speed type calculation is performed to obtain the speed type PID adjustment calculation signal ΔMV _{n corresponding} to the current change, and then the speed type-position type signal conversion means 15 is introduced. Here, the position-type PID adjustment signal MV _n is obtained by the arithmetic expression of MV _n = MV _n-1 + ΔMV _n (2).

In the above equation, K _p : proportional gain, T
_I : integration time, T _D : derivative time, Δt: control cycle,
e _n: this time of the deviation signal, e _n-1: the last of the deviation signal, e
_n-2 : previous and previous deviation signal, MV _n : current adjustment signal, M
V _n-1 : the previous adjustment signal, ΔMV _n : the change amount of the current adjustment signal.

However, since the position type PID control signal MV _n obtained as described above is usually 0 to 100%,
The signal range is reduced by 50% by the subtracting means 16 to be -50 to
After a signal of 0 to + 50%, the upper and lower limit limiter 17 limits the signal with a predetermined upper limit limit value + δ and a lower limit limit value -δ, and then guides it to a subsequent adding unit 18, where the basic operation amount of the FF control system is set. K · SV _n is corrected by the output of the FB control system to form a load distribution command signal, and this load distribution command signal is used by the corresponding boiler 2
And supplies to _1.

[0008]

However, the following problems have been pointed out in the above-mentioned target value FF / FB control device.

(1) Since the target value FF control component and the PID control component are superposed when the target value SV _n is changed,
While the target value tracking characteristic is oscillating even with only the PID control component, PD is also added to the FF control gain, that is, the proportional gain and the differential gain, so that the gain becomes high and the controllability deteriorates.

(2) When the position-type PID adjustment signal MV _n is caught by the upper and lower limit limiting means 17 and the deviation e _n remains, the integration operation of the PID adjustment calculating means 14 continues to continue at a certain point. When the deviation e _n moves in the opposite direction, the operation signal corresponding to, for example, the upper limit value of the upper and lower limit limiting means 17 is continuously output, and it takes time for the operation signal to return to the original state, which is a so-called reset windup problem. Occurs, and controllability also deteriorates significantly in this respect. (3) Since the target value FF control and the FB control are connected by the position type signal, it is unsuitable for sophistication such as gain adaptive type.

(4) Further, similarly to the above, the target value FF
Since the control and the FB control are combined by the position type signal,
The so-called balanceless bumpless process, which is a smooth transition during automatic-manual switching, is complicated.

The present invention has been made in view of the above situation. When the FB control has two degrees of freedom with respect to the change of the target value, the optimum controllability is secured, and when the adjusting signal is in the expanding direction by the integral operation. Reset windup is prevented by stopping the integration operation, or by executing the integration operation when the adjustment signal is in the direction where the adjustment signal is canceled by the integration operation, and further executes the velocity type adjustment calculation for the FB control component and the FF control component, respectively. It is an object of the present invention to provide a target value FF / FB controller capable of sufficiently coping with advancement and balanceless bumplessness at the time of switching by combining them after the above.

[0013]

In order to solve the above-mentioned problems, the invention corresponding to claim 1 includes a target value FF (feedforward) control unit for outputting a quick response to a change in the target value SV _n. , An FB (feedback) control unit for correcting and controlling the output of the target value FF control unit using an adjustment calculation signal obtained by executing an adjustment calculation based on the target value SV _n and the control amount PV _n from the controlled object Target value F combining and
In the F / FB controller,

As the FB control unit, when the optimum two-degree-of-freedom coefficient of P (proportional) operation as FB control is α ₀ , the proportional gain of P operation is K _p , and the gain of target value FF control is K, At least P-motion two-degree-of-freedom coefficient α (= α ₀ -K
/ K _p ), the adjustment calculation is performed based on the deviation between the calculated target value SV _n ′ from the target value filter means and the control amount PV _n , at least I (integration)
Speed type PI or speed type PID with separate adjustment calculation
(D: differential) adjustment calculation means, switch means provided on the output side of the I adjustment calculation means, speed PI or PID adjustment calculation signals obtained by the speed PI or speed PID adjustment calculation means are added and synthesized. Have a synthesizing means to

Further, the velocity type PI or PID adjustment calculation signal obtained from the synthesizing means and the FF of the FF control section.
A signal conversion means for adding a speed type FF control signal ΔFF _n obtained by a difference calculation of the control signal FF _n (= SV _n · K) and then converting it to a position type FF / FB adjustment signal, and this signal conversion means. Upper and lower limit limiting means for limiting the position type FF / FB adjustment signal from the above with an upper and lower limit limiting value and outputting an operation signal,

An upper / lower limit limit deviation determining means for determining that the position type FF / FB adjustment signal exceeds the upper / lower limit limiting value based on the input / output difference signal of the upper / lower limit limiting means, and an output Δ of this determining means. L _n-1 and the output ΔI _n of the I adjustment calculation means
And the same sign, a target value FF provided with integration operation control means having the same sign determination means for judging that the adjustment signal is in the expanding direction by the integration operation and turning off the switch means to stop the integration operation. / FB controller.

Next, in the invention according to claim 2, the position type FF / FB adjustment signal is set within the upper and lower limit limit values based on the input / output difference signal of the upper and lower limit limit means, particularly as integral operation control means. whether the determining operation signal determining means whether there, said by the integral operation when the output △ I _n the output △ L _n-1 and the velocity-type I regulating operation means of the operation signal determination unit is zero or opposite sign And a zero / different sign determining means for executing the integration operation by turning on the switch means when it is determined that the adjustment signal is in the direction of canceling,

Further, the invention corresponding to claim 3 relates to the integral operation control means, wherein the position type FF / FB adjustment signal exceeds the upper and lower limit values based on the input / output difference signal of the upper and lower limit means. Of the upper and lower limit value deviation determination means for determining the above, the output ΔL _{n-1 of} this determination means, the speed type FF control signal ΔFF _n , the output ΔP _n of the P adjustment calculation means or the PD adjustment calculation means. The added value of the output ΔPD _n and the above I
When the output ΔI _n of the adjustment calculation means has the same sign, it is judged by the integration operation that the adjustment signal is in the expanding direction, and the switch means is turned off to stop the integration operation. Is.

Further, in the invention corresponding to claim 4, similarly, in the integral operation control means, the position type FF / FB adjustment signal is within the upper and lower limit values based on the input / output difference signal of the upper and lower limit limiting means. Operation signal determination means for determining whether or not there is an output ΔL _{n-1 of the} operation signal determination means, speed type FF
Control signal △ FF _n, when the output △ I _n the sum of the output △ PD _n of the output △ P _n or the PD adjusting operation means of the P regulation computation means and said I regulatory calculation means is zero or opposite sign This is a configuration provided with zero / different sign determination means for determining that the adjustment signal is in a direction to be canceled by the integration operation and turning on the switch means to execute the integration operation.

[0020]

Therefore, in the invention corresponding to claims 1 and 3, the speed type PI or PI is obtained by taking the above means.
In the FB control unit of D, when the optimum two-degree-of-freedom coefficient for P operation is α ₀ , the proportional gain for P operation is K _p , and the gain for the target value FF control is K, at least two degrees of freedom for P operation are provided. By providing the target value filter means having the coefficient α (= α ₀ −K / K _p ), the controllability with respect to the change of the target value and the controllability with respect to the change of the control amount can be independently adjusted, which is optimum. It is possible to obtain excellent controllability. Further, when the input / output difference signal of the upper / lower limit limiting means is a signal other than zero in the upper / lower limit limit deviation determining means, it is determined that the position type FF / FB adjustment signal exceeds the upper / lower limit limiting value of the upper / lower limit limiting means. A signal obtained by the upper / lower limit limit deviation determining means or an output signal of the determining means, an addition signal of the speed type P adjustment calculation signal and the speed type FF control signal, and an output signal of the speed type I adjustment calculation means. , The speed type FF / FB adjustment signal acts in such a direction that the speed-type FF / FB adjustment signal further expands from the upper and lower limit values by the integration operation. Therefore, at this time, if the switch means is turned off to stop the integration operation, Operation reset windup can be prevented. Further, since the FB control and the FF control are also combined by performing the velocity type calculation, the adjustment signal up to the previous time has already been secured in the signal converting means, and the adjustment signal of the current value may be added to this adjustment signal. Therefore, it is possible to easily combine the external signals and correct the gain, and it is possible to realize the balanceless bumpless mode at the time of automatic-manual switching.

Next, in the invention according to claims 2 and 4, when the input / output difference signal of the upper / lower limit limiting means is zero in the operation signal judging means, the position type FF / FB adjustment signal is the upper / lower limit limiting means. It can be determined that the value is within the upper and lower limit values, and the signal obtained by the operation signal determination means or the output signal of the determination means, the addition signal of the speed type P adjustment calculation signal and the speed type FF control signal, and the speed type I adjustment are provided. When the output signal of the computing means is zero or of a different sign, the speed-type FF / FB adjustment signal exceeding the upper and lower limit values is canceled by the integration operation, so that the switching means is used at this time. With the configuration in which is turned on to execute the integration operation, reset windup of the integration operation can be prevented.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. First, an embodiment of the invention according to claim 1 will be described with reference to FIG.

This control device uses a target value FF control unit 20 which outputs in response to changes in the target value SV _n , and a speed type which corrects and controls the target value FF control component using a speed type PI adjustment calculation signal for FB control. A 2-degree-of-freedom PI control unit 30 is provided.

The target value FF control unit 20 determines the target value SV
_The coefficient means 21 for multiplying _n by the FF control gain K (K is a value near 1) to obtain the static compensation amount FF _n = K · SV _n for the FF control, and the current value FF _{n of the} static compensation amount. And a difference value from the previous value FF _n-1 for static compensation, that is, a difference calculation means 22 for extracting the speed type FF control signal ΔFF _n . Incidentally, the speed-type FF control signal △ FF _n determined by the difference calculating means 22 can be expressed by _{△ FF n = FF n -FF n} -1 = K · (SV n -SV n-1) = K · △ SV n ..

On the other hand, the velocity type two-degree-of-freedom PI control section 30 is
A target value filter means 31 for receiving the target value SV _n and making the P motion at least two degrees of freedom, and the target value filter means 3
Calculation target value SV _n ′ and control amount P output via 1
A deviation calculation means 32 and a V _n a deviation e _n, the following (3) using the deviation e _n from the deviation calculating means 32 and Equation (4) speed type P regulating operation signal based on the equation △ P _n
And speed type P adjustment calculation means 33 and speed type I adjustment calculation means 34 for obtaining the speed type I adjustment calculation signal ΔI _n . _{△ P n = K p (e} n -e n-1) ...... (3) △ I n = K p (△ t / T I) e n ...... (4)

Further, the speed type two-degree-of-freedom PI control section 30
Is provided with an addition means 36 on the output side of the speed type I adjustment calculation means 34 via a switch means 35.
At 6, the output of the speed type P adjustment calculation means 33 and the output of the speed type I adjustment calculation means 34 are always added to obtain a speed type PI adjustment calculation signal, and this speed type PI adjustment calculation signal is added to the subsequent addition means. It is configured to send to 37. The addition means 37 outputs the speed type FF control signal ΔFF _n from the difference calculation means 22, the output signal ΔP _n of the speed type P adjustment calculation means 33 and the output signal ΔI of the speed type I adjustment calculation means 34. _n and are added and synthesized, and the signal after this addition and synthesis is velocity type FF / F
It is output as a B adjustment signal ΔMV _n . Reference numeral 41 denotes a velocity type-position type signal converting means, which takes in the velocity type FF / FB adjustment signal ΔMV _n and based on the following equation (5): MV _n = MV _n-1 + ΔMV _n = MV _{n −1} + ΔP _n + ΔI _n ′ + ΔFF _n (5) The position-type FF / FB adjustment signal MV _n is calculated and then sent to the upper and lower limit limiting means 42. However, in the above equation, MV _{n is the} current position type FF / FB adjustment signal,
MV _n-1 : Previous position type FF / FB control signal.

The upper and lower limit limiting means 42 is a position type FF /
Upper and lower limit value setting means 43 for the FB adjustment signal MV _n
The operation signal M while limiting using the upper limit value (K · SV _n + δ) and the lower limit value (K · SV _n −δ) from
V _n ′ is taken out and applied to a controlled object (not shown). The upper limit value (K · SV _n + δ) and the lower limit value (K
・ SV _n −δ) is the static compensation FF of the target value FF control
It is obtained by adding or subtracting a predetermined value δ from the signal generating means 431 to _n (= K · SV _n ). The function of the upper and lower limit limiting means 42 may be to select the intermediate value of the three input signals.

Further, between the input and output terminals of the upper and lower limit limiting means 42, zero is output when the position type FF / FB control signal MV _n is within the upper and lower limit limits, and when the upper and lower limit limits are exceeded. High and low limit value deviation signal ΔL that is a signal other than zero
An upper / lower limit limit value deviation determining means 44 for outputting _n−1 is provided, and the upper / lower limit limit value deviation signal ΔL _n−1 is sent to the integration action tendency extracting means 45. This integration operation tendency extraction means 4
5 is the current output signal ΔI _n of the speed type I adjustment calculation means 34.
By multiplying the previous value ΔL _n-1 of the upper and lower limit value deviation signal of the upper and lower limit value deviation determining means 44, an integral action tendency signal that changes with the passage of time is extracted. Same sign discrimination means 46 when the _{△ I n · △ L n-} 1> 0 △ and I _n △
It is determined that L _n-1 has the same sign, and in this case, it is determined by the integration operation that the position type FF / FB adjustment signal is moving in the direction of expanding beyond the upper and lower limit values, and the switch means 35 By turning off, the integration operation is stopped. Therefore, according to the configuration of the above-described embodiment, various conventional problems can be solved.

First, the target value SV _n is calculated through the target value filter means 31 and the calculated target value SV _n ′ and the control amount P are obtained.
PI adjustment calculation is executed based on the deviation e _{n from} V _n to obtain a velocity-type PI adjustment calculation signal. At this time, the 2-degree-of-freedom coefficient α in the P operation (proportional gain) of the target value filter means 31 is FF controlled. Since the target value FF control and the two-degree-of-freedom PI control are combined with each other, the target value following characteristic and the disturbance suppressing characteristic can be simultaneously controlled to the optimum state. Incidentally, the transfer function H (s) of the target value filter means 31 can be expressed by the following equation (6). H (s) = (1 + αT _I・ s) / (1 + T _I・ s) …… (6)

Where α is a two-degree-of-freedom coefficient of proportional gain,
T _I : integration time, s: Laplace operator. here,
When the transfer function between the controlled variable PV and the manipulated variable MV in the case of only the FB control is C _PM (s) and the transfer function between the target value SV and the manipulated variable MV is C _SM (s), the following equation (7) is obtained. And it becomes like Formula (8). C _PM (s) = MV / PV = K _p {1 + 1 / (T _I · s)} (7) C _SM (s) = MV / SV = K _p {α + 1 / (T _I · s)} ... … (8)

Therefore, the target value filter means 31 is (6)
When the transfer function H (s) like the expression is taken, only the P motion as shown in the expressions (7) and (8) has two degrees of freedom. Here, the two-degree-of-freedom coefficient α of the proportional gain is selected, for example, by the following equation (9). α = α ₀ −K / K _p (9)

However, K: target value FF control gain, K _p :
Proportional gain, α ₀ : Optimal 2-DOF coefficient of proportional gain when only FB control (0.4 vicinity), α: Optimal 2-DOF coefficient of proportional gain when target value FF control is combined is there.

That is, if the two-degree-of-freedom coefficient α of the proportional gain is selected as shown in the equation (9), the controllability with respect to the target value FF / FB control and the controllability with respect to the control amount change are completely achieved. It can be adjusted independently, and thereby optimal controllability can be obtained, and the problem (1) of the conventional device can be solved.

Next, the output Δ of the speed type P adjustment calculation means 33
After P output of _n and the velocity-type I regulating calculating means 34 △ adds the I _n and the speed-type FF control signal △ FF _n, and converted into a position type FF / FB adjustment signal MV _n further signal conversion unit 41,
This is introduced into the upper and lower limit limiting means 42. At this time, if MV _n is within the upper and lower limit limiting values, the input and output values of the upper and lower limit limiting means 42 become the same, so the output of the upper and lower limit limiting value deviation determining means 44 is It can be determined that zero, that is, MV _n does not deviate from the upper and lower limit values.

However, when MV _n deviates from the upper and lower limit limit values, the input and output values of the upper and lower limit limit means 42 differ, and the non-zero signal ΔL _n-1 is output from the upper and lower limit limit deviation deciding means 44. Then, this is sent to the integration operation tendency determination means 45. This integral motion tendency judging means 45 is provided with the current speed type I.
The adjustment calculation signal ΔI _n is input. Therefore, in this integration operation tendency judging means 45, the tendency of the integration operation can be known by multiplying ΔL _n-1 by ΔI _n . That is, the output ΔL
_{If n-1} and ΔI _n have the same sign, the integration operation is acting in the same direction, and the position type FF / FB adjustment signal is in the direction of expanding beyond the upper and lower limit values. Therefore, the same sign discriminating means 46 discriminates whether or not ΔL _n-1 and ΔI _n have the same sign by ΔL _n-1 · ΔI _n > 0, and when they have the same sign, the switch means 35 is operated. Set to off and stop integration operation. Therefore, the reset windup of the integral operation, which is the problem (2) of the conventional device, can be completely prevented.

Further, since the FF control and the FB control are combined by completely performing the velocity type calculation, the combination with the external signal and the gain correction can be easily performed, and the approach to the sophistication becomes easy. Moreover, since the current value ΔMV _n is added to the position type operation signal MV _n-1 up to the previous time, there are problems (3) and (4) of the conventional apparatus, for example, balanceless during automatic-manual switching. Can be bumpless.

In the above embodiment, the FF / FB adjustment signal is caught by the upper and lower limit values, and ΔL _n-1.
When ΔI _n > 0, it is detected that the FF / FB adjustment signal exceeds the upper and lower limit values in the expanding direction. For example, ΔL _n-1 > 0 and ΔI _n > 0. Or △ L _n-1
It is equivalent if detected by a logical sum (OR) of <0 and ΔI _n <0.

Next, an embodiment of the invention according to claim 2 will be described with reference to FIG. That is, this control device has a completely opposite idea regarding whether or not to execute the integration operation of FIG. That is, the judgment function for executing the integration operation is provided instead of stopping the integration operation.

Specifically, it is determined whether or not the position type FF / FB adjustment signal MV _n of the speed type / position type signal converting means 41 is within the upper and lower limit values, that is, when it is within the upper and lower limit values, zero is set. The operation signal determining means 51 that outputs a signal other than zero at other times and the output of the operation signal determining means 51 and the output of the speed type I adjustment calculating means 34 are multiplied to determine the tendency of the integration operation. The integration operation tendency determining means 52 to be viewed and the zero / different sign determining means 53 for determining whether the output of the integration operation tendency determining means 52 is zero or a different sign are provided, and the integration operation is performed at the time of zero or a different sign. Is determined to be in the reduction direction, the switch means 54 is turned on, and the integration operation is executed.

Therefore, according to the construction of this embodiment, the output of the integration operation tendency judging means 52 is zero or minus, that is, ΔL _n-1 · ΔI _n ≤0 (ΔL _n-1 and Δ I
A zero / different sign discriminating means 53 for discriminating that _n is a different sign or one of them is zero, and if the sign is zero or a different sign, the position type FF / FB adjustment signal MV _n is the upper and lower limit limiting means. Is the upper or lower limit value of 42 not caught?
Since the position-type FF / FB adjustment signal MV _n is in a direction to be resolved against the limit value over by the integration operation, the switch means 54 is set to ON to execute the integration operation. As a result, the position type FF / FB adjustment signal MV _n quickly enters the upper and lower limit values, and when the integration operation is in the expanding direction and the switch means 54 is set to OFF, the integration operation You can completely prevent reset windup.

Of course, in this embodiment, since the velocity type two-degree-of-freedom PI control unit 30 having the target value filter means 31 having the same structure as that of FIG. 1 is provided, the same effect as that of FIG. 1 can be obtained. is there.

In this embodiment, ΔL _n-1 · ΔI _n
When ≦ 0, it is detected that the position type FF / FB adjustment signal is within the upper and lower limit limit values and that the position type FF / FB adjustment signal due to the integration operation is in the direction of eliminating the upper and lower limit values. _n-1 ≧ 0 and ΔI _n <0 or ΔL _n-1
It is equivalent even if it is detected by the logical sum of ≦ 0 and ΔI _n > 0.

Further, an embodiment of the invention according to claim 3 will be described with reference to FIG. This control device includes upper and lower limit value deviation determining means 44 and integral operation tendency determining means 4.
5, the operation amount calculating means 61 is provided this time to ensure the accuracy of the reset / windup prevention function of the integration operation. That is, in FIG. 1, the integration operation is stopped when the previous manipulated variable has reached the limit and ΔL _n-1 and ΔI _n have the same sign, whereas in the present embodiment, ΔL _n-1.
Instead of the above, the current manipulated variable calculating means 61 calculates ΔL _n-1 +
By performing the calculation of ΔP _n + ΔFF _n , the operation amount was caught by the limit this time, and [ΔL _n-1 + ΔP _n
The integration operation is stopped when [ _n + ΔFF _n ] and ΔI _n have the same sign.

In this embodiment, [ΔL _n-1 + ΔP _n
+ ΔFF _n ] · ΔI _n > 0 and the position type FF / FB control signal exceeds the upper and lower limit limits, and the direction in which the position type FF / FB control signal due to the integral operation exceeds the upper and lower limit limits and expands However, for example, [ΔL _n-1 + ΔP
_n + ΔFF _n ]> 0 and ΔI _n > 0 or [ΔL _n-1 +
Even if the logical sum of ΔP _n + ΔFF _n ] <0 and ΔI _n <0 is detected, they are equivalent.

Further, an embodiment of the invention according to claim 4 will be described with reference to FIG. This control device is based on the opposite idea as to whether or not to execute the integration operation of FIG. That is, the judgment function for executing the integration operation is provided instead of stopping the integration operation.

That is, in this embodiment, the current manipulated variable calculation means 71 is provided between the operation signal determination means 51 and the integration operation tendency determination means 52, and the accuracy of the reset / windup prevention function of the integration operation is ensured. To do. That is, in FIG. 2, the integration operation is executed when the previous manipulated variable is within the upper and lower limit values and ΔL _n-1 and ΔI _n have different signs, whereas in the present embodiment, ΔL _{n is used.} Instead of _-1, the current manipulated variable calculating means 61 uses ΔL _n-1 + ΔP _n + ΔFF
By calculating _n , the current manipulated variable is within the limit value, and [ΔL _n-1 + ΔP _n + ΔFF _n ] and ΔI _n
It has a function to execute the integration operation when and have different signs.

In this embodiment, [ΔL _n-1 + ΔP
_n + ΔFF _n ] · ΔI _n ≤0, the operation output is within the upper and lower limit limits, and when the control signal exceeds the upper and lower limit limits, the integral operation is in the direction of canceling the limit over-value. It is detected that there is, for example, [ΔL _n-1 + ΔP _n
+ ΔFF _n ] ≧ 0 and ΔI _n <0 or [ΔL _n-1 + Δ
It is equivalent even if the logical sum of P _n + ΔFF _n ] ≦ 0 and ΔI _n > 0 is detected. Further, although the speed type two degrees of freedom PI control is described in the embodiments of the above claims, the speed type two degrees of freedom PID control can be similarly applied.
Besides, the present invention can be variously modified and implemented without departing from the scope of the invention.

[0048]

As described above, according to the present invention, the following various effects are exhibited.

According to the first and third aspects of the present invention, by combining the target value FF control and the two-degree-of-freedom PI control, the controllability with respect to changes in the target value and the control amount can be greatly improved, and further, the position type FF / FB When the adjustment signal exceeds a certain limit value and the integration operation is in the expanding direction, the integration operation is stopped, so that reset windup can be reliably prevented. In addition, it is possible to easily realize gainless correction and balanceless bumpless at the time of automatic-manual switching, and it is possible to easily achieve an advanced approach.

Next, the inventions of claims 2 and 4 relate to claims 1 and 2.
Similar to the invention of 3, the controllability can be greatly improved, and
Gain correction and balanceless bumpless operation at the time of automatic-manual switching can be easily realized. Furthermore, position type FF / FB
Since the integration operation is performed when the adjustment signal is within the limit value and the integration operation is in the canceling direction, the reset windup can be prevented as a result.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a target value FF / FB control device according to claim 1.

FIG. 2 is a configuration diagram showing an embodiment of a target value FF / FB control device according to claim 2;

FIG. 3 is a configuration diagram showing an embodiment of a target value FF / FB control device according to claim 3;

FIG. 4 is a configuration diagram showing an embodiment of a target value FF / FB control device according to claim 4;

FIG. 5 is a schematic configuration diagram of a conventional general boiler load system.

FIG. 6 is a block diagram of a conventional target value FF / FB control device.

[Explanation of symbols]

20 ... Target value FF control section, 21 ... Coefficient means, 22 ... Difference computing means, 30 ... Velocity type 2 degrees of freedom PI or PID control section, 31 ... Filtering means, 33 ... Velocity type P adjustment computing means, 34 ... Velocity type I adjustment calculation means, 35 ... switch means, 36, 37 ... addition means, 41 ... signal conversion means, 42
... upper and lower limit limiting means, 43 ... upper and lower limit limiting value setting means, 44
... upper / lower limit limit deviation means, 45, 52 ... integral action tendency extraction means, 46 ... same sign discrimination means, 51 ... operation signal determination means, 53 ... zero / different sign discrimination means, 61, 71 ... current operation amount calculation means ..

Claims (4)

[Claims] 1. A target value FF (feedforward) control unit for outputting a quick response to a change in the target value SV _n ,
An FB (feedback) control unit that corrects and controls the output of the target value FF control unit using an adjustment calculation signal obtained by performing an adjustment calculation based on the target value SV _n and the control amount PV _n from the controlled object. In the target value FF / FB control device, the optimum two-degree-of-freedom coefficient of P (proportional) operation as FB control is α ₀ , the proportional gain of P operation is K _p , and the target value FF as the FB control unit. When the control gain is K, a target value filter means having at least a two-degree-of-freedom coefficient α (= α ₀ −K / K _p ) for P operation, and a calculation target value SV _n ′ from this target value filter means. Of the speed type PI or the speed type PID (D: differential) adjusting calculation means, which separates at least the I (integral) adjusting calculation, and performs the adjusting calculation based on the deviation between the control amount PV _n and the control amount PV _n . Switch hand provided on the output side The speed type PI or the speed type PID adjusting arithmetic means, and the speed type PI or PID adjusting arithmetic signal, and the speed type PI or P obtained from the synthesizing means.
ID adjustment calculation signal and FF control signal FF of the FF controller
After adding the speed type FF control signal ΔFF _n obtained by the difference calculation of _n (= SV _n · K), the position type FF / F
A signal converting means for converting into a B adjusting signal, an upper and lower limit limiting means for limiting the position type FF / FB adjusting signal from the signal converting means with an upper and lower limit limiting value, and outputting an operation signal, and an upper and lower limit limiting means. Upper / lower limit limit deviation determination means for determining that the position type FF / FB adjustment signal exceeds the upper / lower limit limit value based on the input / output difference signal, and the output Δ of this determination means
When L _n-1 and the output ΔI _n of the I adjustment calculation means have the same sign, the integration operation determines that the adjustment signal is in the expanding direction and the switch means is turned off to stop the integration operation. A target value FF / FB control device comprising: integral operation control means having a determination means. 2. The integral operation control means according to claim 1,
An adjustment signal determination means for determining whether or not the position type FF / FB adjustment signal is within the upper / lower limit limit value based on the input / output difference signal of the upper / lower limit limitation means, and an output ΔL of the adjustment signal determination means. _{When n-1} and the output ΔI _{n of the} speed type I adjustment calculation means are zero or have different signs, it is judged that the adjustment signal is in the direction to be canceled by the integration operation, and the switch means is turned on to perform the integration operation. A target value FF / FB control device having a zero / different sign determining means for executing. 3. The integral operation control means according to claim 1,
An upper / lower limit limit deviation determining means for determining that the position type FF / FB adjustment signal exceeds the upper / lower limit limiting value based on the input / output difference signal of the upper / lower limit limiting means, and an output ΔL _{n of} this determining means. _-1, velocity type FF control signal △ FF _n, and an output △ I _n the sum of the output △ PD _n of the output △ P _n or the PD adjusting operation means of the P regulation computation means and said I regulatory computing means the Target value FF / FB control device, which has the same sign determining means for judging that the adjustment signal is in the expanding direction by the integration operation when it is a sign and turning off the switch means to stop the integration operation. 4. The integral operation control means according to claim 1,
An operation signal determination means for determining whether or not the position type FF / FB adjustment signal is within the upper / lower limit limit value based on the input / output difference signal of the upper / lower limit limitation means, and an output ΔL of this operation signal determination means. _n-1, velocity type FF control signal △ FF _n, the output of the I regulatory calculating means and the sum of the output △ PD _n of the output △ P _n or the PD adjusting operation means of the P regulation computation means △ I _n
When and are zero or different signs, it has a zero / different sign judging means for judging that the adjustment signal is in a direction to be canceled by the integration operation and turning on the switch means to execute the integration operation. Target value FF / FB control device to perform.