JP3263536B2 - Linearizer function generator with automatic correction function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-input one-output broken-line function generator and, more particularly, to a broken-line function generator having an automatic correction function for automatically correcting an output broken-line function.

[0002]

2. Description of the Related Art A one-input one-output linear function generator is an element widely used in, for example, a control device, a driving support device, a monitoring device, and the like in a plant. As shown in FIG. 6, a conventional one-input / one-output broken-line function generator 1 generates a function f (x) according to a set parameter. That is, n
In the case of the point (n ≧ 2) broken line function, the output signal Y for the input signal X is generated as follows.

[0003] (1) when _{X ≦ x 1, Y = y} 1 (2) x m-1 <X ≦ x when _m of (2 ≦ m ≦ n) Y = {(y m -y m-1) / (X _m -x _m-1 )｝ (X-x
When _{m-1) + x m-} 1 (3) X> x n, Y = y n Further, other, when _{X ≦ x 2: Y = {} (y 2 -y 1) / (x 2 -x
_{1)} (X-x 1} ) X> when _{x n-1: Y = {} (y n -y n-1) / (x n -
_xn-1 )｝ (X- _xn ) + _xn .

[0004]

In the above conventional linear function generator 1, the parameters x ₁ ,..., X _n , y ₁ ,.
_n is a fixed value and can be changed only by a setting operation. When the parameter is a fixed value as described above, there is no problem in the case of a linear function that is uniquely determined at the time of design or the like. However, the linear signal function is applied to a preceding signal or a set value of a process control device that changes with time (aging). When using, the operator must perform the reset operation each time,
It is necessary to switch the broken line function. In addition, for example, in a coal-fired thermal power plant, the optimal parameter of the linear function changes due to a change in the type of coal, contamination of the heat transfer surface, and the like. Therefore, it is necessary to reset the parameters according to operating conditions at that time. .

Various methods have been conventionally proposed for automating the parameter resetting operation. In each case, a special line function generator having a dedicated function is used. Complex methods such as applying another device with the ability to change the
There was a problem that economic efficiency and maintainability were poor.

The present invention has been made in view of the above circumstances, and can automatically correct a broken line function by a combination of ordinary arithmetic elements without using a device having a special function. It is an object of the present invention to provide a polygonal line function generator having an automatic correction function excellent in performance.

[0007]

According to the present invention, there is provided a polygonal line function generator having an automatic correction function according to the present invention, which includes a one-input, one-output main polygonal line function generator and a linear line function output from the main polygonal line function generator. A plurality of correction polygonal line function generators for generating a correction polygonal line function for each polygonal point; a Y-axis parameter at each polygonal point of the polygonal line function output from the main polygonal line function generator;
Means for obtaining a difference from the state quantity of the load, a memory for storing the difference obtained by this means as a correction value,
The condition of the load is monitored, and a predetermined correction condition is satisfied.
Means for instructing the memory to write a correction value,
Multiplying means for multiplying the correction value stored in the memory by the output of the corresponding correction linear function generator; and adding the multiplication result of the multiplication means to the linear function output from the main linear function generator for correction And an adding means for obtaining the obtained broken line function.

[0008]

First, a manipulated variable (or a state variable) given from, for example, a unit load and a function value representing an initial set value output from the main broken line function generator are input to a subtractor to obtain a deviation value between the two. Store in analog memory. The content stored in the analog memory is updated each time the unit load satisfies a predetermined condition.

The correction value stored in the analog memory is multiplied by a linear function output from a correction linear function generator. Then, the result of the multiplication is sent to the adding means, and is added to the linear function output from the main linear function generator for correction.

As described above, the Y-axis parameters of the line function output from the main line function generator are automatically corrected in accordance with the load condition, and an appropriate output value of the line function is always obtained.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. First, the basic configuration of the present invention will be described with reference to FIG. In FIG. 1, 1 is a main broken line function generator for generating a broken line function f ₀ (x), and 2 is a correction broken line function generator. The correction linear function generator 2 generates a linear function f ₀
It is provided corresponding to each correction point of (x). The broken line function generators 1 and 2 generate a broken line function of one input and one output, and receive an input signal X. The output of the correction linear function generator 2 is input to the multiplier 3 and added to the correction data. Then, the output of the multiplier 3 and the output of the main broken line function generator 1 are added by the adder 4 and extracted as an output signal Y.

In a state where the main polygonal function generator 1 generates four polygonal functions f ₀ (x) as shown in FIG. 2A, for example, a point (x ₃ , y ₃ ) is set to a point ( x ₃ , y
If it is desired to change to ₃ ′), as the polygonal function generator 2, as shown in FIG. 2B, the polygonal function f ₃ (x) (0 ≦ f ₃ ≦
1.0) is used. The value of f ₃ is shown in FIG.
As shown in (b), when input ≦ x ₂ : output f ₃ (x) = 0.0 x ₂ <when input ≦ x ₃ : output f ₃ (x) = (X−x
_{2) / (x 3 -x 2} ) x 3 < When the input ≦ x _4: Output _{f 3 (x) = - {} (X-
x ₃ ) / (x ₄ −x ₃ ) １．０ + 1.0 x ₄ <For input: output f ₃ (x) = 0.0.

[0013] Then, the multiplier 3 gives the "y ₃ '-y _3" as the correction data, the output f ₃ of the polygonal line function generator 2
(X), and the multiplication result is input to the adder 4 and added to the output of the main broken line function generator 1 to obtain an output signal Y.
Therefore, the output signal Y of the adder _{4, Y = f 0 (x)} + (y 3 '-y 3) · f 3 (x) , and the point (x _3, y ₃₎ is a point (x _3, y ₃ ′). The case where one point (x3, y3) is changed has been described above. If this is expanded to all n points, the output signal Y becomes as shown in FIG.

[0014]

(Equation 1) And the broken line function f ₀ (x) is corrected at all n points.

F _i (x) in the above equation is a broken line function of “0 ≦ f _i ≦ 1.0” shown in FIG. 3B, and specifically takes the following values. [F ₁ ] When X ≦ x ₁ : f ₁ = 1.0 x ₁ <X ≦ x ₂ : f ₁ = − ｛(X−x ₁ ) /
_{(X 2 -x 1)} +} 1.0 X> x 2 _{when: f 1 = 0.0 [f i} (i = 2~n-1)] When _{X ≦ x i-1: f} i = 0. 0 x _i-1 <when _{X ≦ x i: f i =} (X-x i-1) / (x
_i− x _i−1 ) x _i <X ≦ x _{i + 1} : f _i = − ｛(X−x _i ) /
(X _{i + 1} −x _i )｝ + 1.0 When X> x _{i + 1} : f _i = 0.0 [f _n ] When X ≦ x _n−1 : f _n = 0.0 x _{n− 1} <when _{X ≦ x n: f n =} (X-x n-1) / (x
_n− x _n−1 ) When X> x _n : f _n = 1.0 As is apparent from the above equation (1), by automatically changing the value of “y _i ′ −y _i ”, the linear function is obtained. Has the same function as automatically changing the parameter of the Y-axis.

Next, a specific embodiment of the present invention will be described with reference to FIG. FIG. 4 shows an example in which the present invention is applied to a driving support device for an oil-fired power generation unit having an output of 350 MW, for example. This device incorporates the control calculation function used for the control device as it is, and has a function of giving a value when the unit is settled as a function of the unit load and the like for various state quantities and various operation quantities. An output linear function generator is used.

The data indicating the unit load is a linear function f ₀
(X) are input to the main broken line function generator 1 and the corrected broken line function generators 2a, 2b,..., 2n. The linear function generator 2a for correction is a linear function f ₁ (x), the linear function generator 2b is a linear function f ₂ (x), and the linear function generator 2n
Generates a linear function f _n (x). That is, the linear function generators 2a, 2b,..., 2n are provided with correction points that set the linear functions f ₁ (x) to f _n (x) described in FIG. For example, 50, 70, 100, 16
Occurs at 0, 300, 350 MW. More specifically, the broken line function generator 2a generates a broken line function f ₁ (x) that is “1.0” at 50 MW or less and “0.0” at the next correction point 70 MW. , Broken line function generator 2
b is “0.0” at 50 MW, and “1.b” at 70 MW.
A linear function f ₂ (x) that is “0” and “0.0” at the next correction point 100 MW is generated. Then, the polygonal line function generator 2n generates a polygonal line function f ₂ (x) that is “0.0” at 300 MW and “1.0” at 350 MW or more.

The broken line function generators 2a, 2b,..., 2n
Are input to multipliers 3a, 3b,..., 3n, respectively. The multipliers 3a, 3b,..., 3n are supplied with the values set in the analog memories 11a, 11b,.

The state quantity (or operation quantity) sent from the unit load is input to the + terminal of the subtractor 13 through a sufficiently long time constant, for example, a first-order lag element 12 of 5 minutes. The minus terminal of the subtractor 13 has a main broken line function generator 1
Is input via the fifth-order first-order lag element 14. The influence of instantaneous fluctuation is suppressed by the first-order lag elements 12 and 14. The subtractor 13 obtains a difference between the state quantity (or operation amount) sent from the unit load and the state quantity (or operation amount) before correction output from the main polygonal line function generator 1 and obtains the analog memory 11a. , 11b,
.., 11n. This analog memory 11a, 1
.., 11n store input signals in accordance with instructions from the write control unit 20.

The correction broken line function generators 2a, 2b,
, 2n and the analog memories 11a, 11b,
, 11n are the multipliers 3a, 3b,.
, And the result is added by adders 15a, 15b,... Further, the output value of the adder 15a and the output value of the main broken line function generator 1 are added by the adder 4, and are taken out as a set value of the corrected state quantity (or operation quantity).

On the other hand, the write control unit 20 includes monitor circuits 21a, 21b,.
1n. Monitor circuits 21a, 21b, ..., 2
1n outputs a "1" signal upon detecting that the unit load has entered a specific load zone, and outputs a "0" signal in other states. For example, the monitor circuit 21a operates when the unit load is 45 to 55 MW, the monitor circuit 21b operates when the unit load is 65 to 75 MW, and
n detects the state where the unit load is between 345 and 355 MW and outputs a “1” signal.

The monitor circuits 21a, 21b,..., 21
n are output to AND (logical product) circuits 22a and 22a.
, 22n are input to one of the input terminals. This AN
The output signals of the D circuits 22a, 22b,..., 22n are extracted through, for example, 30-minute ON delays 23a, 23b,. These on delays 23a, 23
, 23n are output from inverters (logical negation)
, 24n, and the AND circuit 22
, 22n are returned to the other input terminals.
The on delays 23a, 23b,.
Are taken out as output signals of the write control section 20, and become write commands to the analog memories 11a, 11b,..., 11b.

Next, the operation of the above embodiment will be described. In the embodiment shown in FIG. 4, f ₀ (x) representing the initial set value is a function of the unit load, and when the value enters a specific load zone continuously for 30 minutes or more, the value at that time is used. The configuration is such that the state quantity is corrected as a new set value.

First, the operation amount (or state amount) given from the unit load and the function value f ₀ (x) representing the initial set value output from the main broken line function generator 1 are first-order lag elements 12 and 14, respectively. Then, the influence of the instantaneous fluctuation is suppressed, and then the difference is input to the subtractor 13 to obtain a deviation value between them.

A condition for correcting the set value when the unit load is 50 MW, that is, when the unit load is 45 to 5
It is stored in the analog memory 11a under the condition that is satisfied once when the data is continuously input for 30 minutes during 5 MW.

The above conditions are detected by the write control unit 20. That is, when the unit load is between 45 and 55 MW, the write control unit 20 detects the state with the monitor circuit 21a and outputs a "1" signal to the AND circuit 22a. In the initial state, the output of the on-delay 23a is "0" and the output of the inverter 24a is held in the "1" state. Therefore, the output signal of the monitor circuit 21a is sent from the AND circuit 22a to the on-delay 23a. . If this state continues for 30 minutes or more, the output of the on-delay 23a becomes "1" and the analog memory 11a
Is given a write command. Thus, the deviation value obtained by the subtractor 13 is written to the analog memory 11a. When the output signal of the ON delay 23a becomes "1", the output of the inverter 24a becomes "0" and closes the gate of the AND circuit 22a. As described above, writing to the analog memory 11a is performed only once when the unit load is continuously between 45 and 55 MW for 30 minutes.

The 5 stored in the analog memory 11a
The correction value for 0 MW is sent to the multiplier 3a, and is multiplied by the linear function output from the linear function generator 2a, and the multiplication result is sent to the adder 4 via the adder 15a. The adder 4 adds the correction value calculated by the multiplier 3a to the linear function f ₀ (x) output from the main linear function generator 1 to perform correction.

Similarly, when the unit load is 70, 100,
At the correction points of 160, 300, and 350 MW, when the condition for correcting the set value is satisfied, a write command is issued from the write control unit 20, and the deviation value output from the subtractor 13 at that time is stored in the analog memory 11b,. , 11n.

Then, the analog memories 11b,.
Based on the stored correction values to n, a polygonal line function f ₀ (x)
Is performed at each correction point. The correction values stored in the analog memories 11a, 11b,..., 11n are updated by outputting a write command from the write control unit 20 every time a predetermined condition is satisfied as described above. As a result, the parameter of the Y-axis of the polygonal function is automatically corrected, and an appropriate output value of the polygonal function is always obtained.

In the above embodiment, the broken line function f ₀
Although the case where (x) and the X-axis breakpoint of the correction linear function f _i (x) coincide with each other has been described, even when the X-axis breakpoint does not match as shown in FIG. folding point x _1, x ₂ of the X-axis of the polygonal line function f _i of use (x), by obtaining the difference [Delta] y _i of the polygonal line function f ₀ (x) in ..., in the same manner as the embodiment described above, i.e., Next formula

[0031]

(Equation 2) The correction process can be performed as shown in FIG.

[0032]

As described above in detail, according to the present invention, a line function having a special function and a special function of automatically changing the parameters of the line function can be incorporated in a separate device.
With the combination of ordinary calculation elements, the Y-axis parameter of the polygonal function is automatically corrected, and an appropriate output value of the polygonal function can always be obtained, so that economy and maintainability can be improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a polygonal line function generator having an automatic correction function according to the present invention.

FIG. 2 is a view for explaining the principle operation of FIG. 1;

FIG. 3 is a diagram for explaining a basic operation of the present invention.

FIG. 4 is a configuration diagram of a polygonal line function generator having an automatic correction function according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram in the case where the break point of the broken line function and the break point of the correction broken line function do not match in the embodiment;

FIG. 6 is an explanatory diagram of a conventional one-input one-output broken line function generator.

[Description of Signs] 1 Main broken line function generator 2a,..., 2n Correction broken line function generator 3a,. , 15b,... Adder 20 Write control unit 21a,..., 21n Monitor circuit 22a,.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-9348 (JP, A) JP-A-2-287713 (JP, A) JP-A-2-91710 (JP, A) JP-A-2- 64719 (JP, A) JP-A-59-109975 (JP, A) JP-A-57-204931, (JP, A) Japanese Utility Model Application Laid-open No. 60-112,861 (JP, U) (58) Fields investigated (Int. ^7, DB name) G06F 1/02 G06F 7/544 G06G 7/28 G05B 13/02

Claims (1)

(57) [Claims] 1. A one-input one-output main broken line function generator, and a plurality of correction broken line function generators for generating a corrected broken line function for each broken point of the broken line function output from the main broken line function generator and means for determining the difference between the state amount of the load and the Y-axis parameters at each corner of the polygonal line function output from the main fold lines function generator, the difference obtained by this means it
A memory for storing each of the correction values, and a state of the load
Monitors the above memory when a predetermined correction condition is satisfied.
Means for writing a correction value to the
Multiplying means for multiplying the corrected correction value by the output of the corresponding linear function generator for correction, and a linear function corrected by adding the result of the multiplication to the linear function output from the main linear function generator And an adding means for obtaining a linear function generator having an automatic correction function.