JPH07234701A - Disturbance non-interference controller - Google Patents

Abstract

PURPOSE:To improve the controllability of gas turbine output in a combined cycle, to remove influence especially by means of disturbance and to improve the responsibility of output to the set output value. CONSTITUTION:Main compensators 31 and 33 suppressing a fluctuation in the flow rate of fuel and that of primary air to a gasification fuel 11 and the pressure disturbance of combustion gas supplied from the gasification fuel 11 to a gas turbine 16 by feedback control and cross compensators 37 and 38 by feed forward control, which precedently pressure-correct combustion gas by correcting an output deviation as against the flow rate of fuel and that of primary air, and provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disturbance non-interference control device for controlling fluctuation of combustion gas pressure due to disturbance in a gasification combined cycle.

[0002]

2. Description of the Related Art For example, IGCC (Integrated Coal Gasi)
In the gasification combined cycle such as fication Conbined Cycle), as a method for performing output control and pressure control when the combustion gas pressure fluctuates due to disturbance such as fuel or air flow rate or suit blower injection, conventionally, the gas turbine lead system, Either one of the gas turbine follow method and the plant emphasis control method was adopted.

FIG. 3 shows a control method of a general IGCC plant, where 11 in the figure is a gasification furnace to be controlled,
12 is a coal adjusting unit that adjusts the inflow amount of coal into the gasification furnace 11, 13 is an air adjusting unit that adjusts the inflow amount of air into the gasification furnace 11, and 14 is from the gasification furnace 11 to the gas turbine 16. Coal gas adjusting unit for adjusting the amount of combustion gas inflow, 15 is a gasification furnace 11
It is a steam adjusting unit that adjusts the amount of steam flowing into the steam turbine 17 from.

The output values (rotational speeds) of the gas turbine 16 and the steam turbine 17 are given to the adder 18 as a decrement, the adder 18 obtains the difference from the output set value, and the difference is sent to the output control section 19. Given.

Further, the gas pressure of the gasification furnace 11 is given to the adder 20 as a decrement, the difference from the pressure set value is obtained by the adder 20, and the difference is given to the pressure control unit 21. However, in the gas turbine reed system, the power generation output is adjusted by the combustion gas inflow amount to the gas turbine 16 by the coal gas adjusting unit 14, as indicated by the arrow using dense upward hatching in the figure. The changing combustion gas pressure is a method in which the coal adjusting unit 12 and the air adjusting unit 13 adjust the amount of fuel and air input.

Further, in the gas turbine follow system, as shown by a dashed arrow in the figure, the power generation output is adjusted by the coal adjusting unit 12 and the air adjusting unit 13 by the amount of fuel and air input, and the combustion gas that changes with it is adjusted. This is a system in which the pressure is adjusted by the coal gas adjusting unit 14 by the combustion gas consumption of the gas turbine 16.

Further, the plant emphasis control system is intended to improve the responsiveness based on the above gas turbine reed system, and in addition to the arrow using the dense upward-sloping hatching in the figure, the downward-sloping coarse control is performed. As shown by the arrow using hatching, the advance signal for the fuel and air input amount is made from the command signal (FF) of the power generation output, and the combustion command is made by adding the operation signal (ΔP) by the feedback of the combustion gas pressure deviation. It is a method of determining the amount of fuel and air input. In this plant emphasis control method, load control may be further suppressed due to pressure control deviation.

[0008]

In each of the control methods described above, the output of the gas turbine 16 is affected by the combustion gas pressure. Therefore, if the combustion gas pressure fluctuates due to fluctuations in the flow rate of fuel or air, fluctuations in suit blower injection, fluctuations in exhaust pressure, etc., the output of the gas turbine 16 is also affected. This is a problem common to any of the conventional gas turbine lead system, gas turbine follow system, and plant emphasis control system, and conventionally, attention has been paid only to disturbance suppression by feedforward control. Therefore, when the suppression of the disturbance with respect to the combustion gas pressure is insufficient, there remains a problem that the output of the gas turbine 16 is affected.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the controllability of the gas turbine output in a combined cycle, particularly to eliminate the influence of disturbance and output against the output set value. An object of the present invention is to provide a disturbance non-interference control device capable of improving the followability of.

[0010]

Means for Solving the Problems and Actions That is, the present invention is as follows: (1) In a disturbance non-interference control device for controlling combustion gas pressure in a gasification combined cycle, fluctuations in the flow rate of fuel and primary air to a gasification furnace and The main compensator that suppresses the pressure disturbance of the combustion gas supplied from the gasification furnace to the gas turbine by feedback control, and the output deviation with respect to the fuel flow rate and the primary air flow rate are corrected in advance to correct the combustion gas And a cross compensator by feedforward control that corrects pressure.

With such a structure, it is possible to improve the controllability of the gas turbine output in the combined cycle, particularly to eliminate the influence of disturbance and improve the output followability with respect to the output set value. (2) In the above item (1), the main compensator is a PID.
The cross compensator is composed of a proportional delay calculator to realize a multivariable series compensator. With such a configuration, the design and adjustment of the control system can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the control method. Since the basic configuration around the controlled object is the same as the conventional configuration shown in FIG. 3, the same parts are designated by the same reference numerals and the description thereof is omitted. .

The difference between the output set value output by the adder 18 and the output values (rotation speed) of the gas turbine 16 and the steam turbine 17 controls the main compensator (C11).
(S)) sent to 31. The main compensator 31 is composed of, for example, a PID calculator, and directly controls the steam adjusting unit 15 that adjusts the flow rate of steam from the gasification furnace 11 to the steam turbine 17, and also from the gasification furnace 11 to the gas turbine. A coal gas adjusting unit 14 for adjusting the flow rate of coal gas to 16 is controlled via a transfer adjusting unit (Σ) 32.

Further, the difference between the pressure set value output from the adder 20 and the output value of the combustion gas pressure of the gasification furnace 11 is sent to a main compensator (C22 (s)) 33 for controlling pressure. The main compensator 33 is further provided with the above-mentioned output set value in the holding section (F
y) is input via 34. The main compensator 33 is composed of, for example, a PID calculator like the main compensator 31 described above. The main compensator 33 adjusts the flow rate of fuel (coal) to the gasification furnace 11 and the primary air flow rate. The air adjusting unit 13 to be adjusted is controlled via the transmission adjusting unit (Σ) 35.

Disturbances due to soot blower injection to the gasification furnace 11 and disturbances to the coal adjusting unit 12 and the air adjusting unit 13 are also input to the transmission adjusting unit 35 via the holding unit (FD) 36. .

Therefore, a cross compensator (C'12 (s)) is used to compensate and control the degree of transmission in the transmission adjusting section 32.
A cross compensator (C'21 (s)) 38 is provided as 37 for compensating and controlling the degree of transmission in the transmission adjusting unit 35.

The cross compensator 37 is composed of, for example, a PL (proportional delay) calculator, and the main compensator 33 is used.
The switch circuit 39 is turned on to operate. Similarly, the cross compensator 38 is composed of, for example, a PL calculator, and operates when the switch circuit 40 is turned on by the main compensator 31.

Next, the operation of the above embodiment will be described. Here, the gasification furnace 11, the gas turbine 16 and the steam turbine 17 to be controlled and their operating end transfer function matrices P (s) are represented, and the transfer function matrix of the series compensator is represented by C
It is represented by (s). At this time, if P (s) is regular, P ⁻¹ (s) and G are given to the given diagonal matrix G (s).
Although C (s) can be obtained as the product of (s), its off-diagonal term Cij (s) is represented by the following equation: the main compensator Cij (s) and the cross compensator C'ij ( s). That is, Cij (s) = gij (s) [adjP (s)] ij / detP (s) (1) C'ij (s) = [adjP (s)] ij / [detP (s)] ij ... (2) (However, i, j = 1, 2.) At this time, the open loop transfer function matrix also becomes diagonal, and even if the feedforward is added to a certain control amount as shown in FIG. It is possible to obtain a control system that does not affect the control amount.

For example, the off-diagonal terms in the case of 2-input 2-output are as follows. That is, C12 (s) = C'12 (s) C22 (s), C21 (s) = C'21 (s) C11 (s) (3) Further, the main compensators 31 and 32 are replaced by PID calculators. By configuring the cross compensators 37 and 38 with PL calculators, respectively, it is possible to obtain a recent disturbance non-interference control system.
For example, when a first-order delay is used as a PL calculator, CPL1 (s) = KP (1 + KC / (s + TC)) (4) (where, KP: proportional gain, TC: cross time constant, KC
: Cross gain. ). Where Kij and Tij are Pi
If the near-term gain of j (s) and the time constant are
The arithmetic unit can be expressed by the following equation. That is,

[0020]

[Equation 1]

A configuration example of the compensator for the case of two inputs and two outputs is shown below. Control target transfer function matrix P (s), series compensator transfer function matrix C (s), forward transfer function matrix G
(S) is described as follows.

[0022]

[Equation 2]

At this time, if P (s) in the above equations (1) and (2) is regular and the desired G (s) is given, the main and cross compensators 31, 33, 37, 38 will become It looks like this: That is,

[0024]

[Equation 3]

Further, the main compensators 31 and 33 are PID calculators, and the cross compensators 37 and 38 whose control target transfer function matrix has been delayed with a first-order delay are composed of first-order PL calculators.

[0026]

[Equation 4] Here, P (s) is assumed to be as follows and is not necessarily regular. At this time, G (s) becomes the following diagonal matrix.

[0027]

[Equation 5]

This corresponds to controlling the diagonal inverse system of the inverse system to be controlled by the main compensators 31 and 33. Incidentally, the following equation is shown as an example of parameter adjustment in the case of 2-input 2-output. C12 (s): KP = -K12 / K11, KC = T12, KC = K11 (T11-T12) (19) C21 (s): KP = -K21 / K22, KC = T21, KC = K22 (T22-) T21) (20) By adopting the above control method, the gas turbine
For the pressure of the combustion gas flowing into 16 to fluctuate due to known disturbances such as load change and suit blower injection, to the feedforward control, and to fluctuate due to unknown disturbances such as fuel flow rate and air flow rate. The feedback control suppresses the influence of those fluctuations on the combustion gas pressure, and at the same time suppresses the influence of the control deviation of the combustion gas pressure on the gas turbine output by the non-interference control.

Due to the disturbance suppression effect by such a double prevention mechanism, the controllability of the output of the gas turbine 16 is improved,
In particular, it is possible to eliminate the influence of disturbance and improve the output followability of the output set value.

In particular, the PID calculator is used as the main compensator 3
It is used as 1, 33 and a simple PL calculator is used as the cross compensator 3
By using it as 7, 38, the design and adjustment of the control system can be simplified.

Further, as shown in FIG. 1, the cross compensator 37,
By providing switch circuits 39 and 40 for 38 and easily switching between use and exclusion, the cross compensator 37, 38 can be used in a situation where the effect of the cross compensator 37, 38 cannot be obtained.
Since the connection of 38 can be temporarily cut off and the conventional control system using only the PID calculator can be restored, the safety and reliability of the entire system can be maintained.

In the present invention as well as the above embodiment, as long as the delay order of the main input / output relation of the output control and the gas pressure control of the gas turbine is lower than the delay order of the subordinate input / output relation. , It can be systematically extended to multiple inputs and multiple outputs.

[0033]

As described above, according to the present invention, it is possible to improve the controllability of the gas turbine output in the combined cycle, especially to eliminate the influence of disturbance and to improve the output followability with respect to the output set value. It is possible to provide a simple disturbance non-interference control device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control circuit configuration according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining an operation according to the embodiment.

FIG. 3 is a block diagram showing a conventional general combined cycle control circuit configuration.

[Explanation of symbols]

11 ... Gasification furnace, 12 ... Coal adjusting section, 13 ... Air adjusting section, 14 ...
Coal gas adjusting unit, 15 ... Steam adjusting unit, 16 ... Gas turbine,
17 ... Steam turbine, 18, 20 ... Adder, 19 ... Output control unit,
21 ... Pressure control unit, 31, 33 ... Main compensator, 32, 35 ... Transmission adjusting unit, 34, 36 ... Holding unit, 37, 38 ... Cross compensator, 39,
40 ... Switch circuit.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location F02C 6/00 C 9/28 C F23N 1/02 101 5/00 F G05B 11/36 L 7531-3H 501 B 7531-3H

Claims (2)

[Claims] 1. A disturbance non-interference control device for controlling combustion gas pressure in a gasification combined cycle, comprising: fluctuation of flow rate of fuel and primary air to a gasification furnace; and combustion gas supplied from the gasification furnace to a gas turbine. Main compensating means for suppressing the pressure disturbance by feedback control, and cross compensating means by feed forward control for correcting the combustion gas pressure in advance by correcting the output deviation with respect to the fuel flow rate and the primary air flow rate. A disturbance non-interference control device characterized by the above. 2. The multi-variable series compensator is realized by forming the main compensating means by a PID calculator and the cross compensating means by a proportional delay calculator.
The disturbance non-interference control device described.