JPH05106468A - Gas turbine control device - Google Patents

Abstract

PURPOSE:To quickly deal with abrupt change in operating conditions by making up a control system of less measuring points required in such a way that transfer function for a control system represented by a specified equation shall be one including transfer function allowing a parameter to be a specified value based on the factor of the partial quadratic of the equation. CONSTITUTION:High pressure air discharged out of a compressor 1 is introduced into a combustor 2, after it has been mixed with main fuel fed from a fuel control valve 5 just before a catalytic layer 4, it passes through the catalytic layer 4, so that it is burnt at low temperature while catalytic reaction is being run by activated catalyst. A bypass valve 6 is provided to control the outlet temperature of the catalytic layer 4. And adjusting the opening of the respective valves 5 and 6 can keep the revolution of a turbine while the outlet temperature of catalyst is being maintained. In this case, when the equation of transfer function for a control system is represented by F(S)=a0+a1S+a2S<2>+a3S<3>+...+ anS<n>, there shall be included the transfer function allowing the parameter to be a specified value, which is proportional to the reciprocal of an attenuation factor represented by a specified equation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine control device which is widely applicable to industrial and aeronautical applications.

[0002]

2. Description of the Related Art In controlling the rotational speed of a gas turbine, high control performance is required in order to suppress fluctuations in rotational speed due to load changes. At this time, the gas turbine characteristics greatly change due to the above load change (see FIG. 4), and also change variously due to various factors such as the temperature and pressure of the outside air. Therefore, it is difficult to maintain the control performance that always satisfies the required specifications with respect to changes in load and the like.

To solve such a problem, a conventional method is to compensate the control parameter based on the measured value of the state of the gas turbine (rotational speed, intake air temperature, intake air pressure, etc.) to maintain the control performance. It is used as one means.

[0004]

However, such means as control parameter compensation based on measured values has the following problems.

(1) In order to perform highly reliable control parameter compensation, it is essential to accurately measure a large number of measurement points such as the number of revolutions, temperature, and pressure. This cannot be dealt with from the aspect of maintainability.

(2) The reliability of the control system is insufficient for changes in gas turbine characteristics due to sudden changes in operating conditions such as sudden changes in load.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to configure a control system with a small number of measurement points and to obtain high reliability even when the operating state changes suddenly. An object is to provide a turbine control device.

[0008]

In the gas turbine controller of the present invention, when the characteristic equation of the transfer function of the control system is represented by the following equation (1), the following partial quadratic equation of the equation (1) is given. It is characterized by having a transfer function having a predetermined value of a parameter defined by the following equation (3), which is composed of the coefficient of the equation (2).

[0009]

Further, in the present invention, it is preferable that the predetermined value is 0.5.

[0011]

[Operation] When the characteristic equation (denominator polynomial) of the transfer function that represents the response of the entire system including the control system is expressed as in equation (1), the damping coefficient of the partial quadratic equation in equation (2) The parameter in Eq. (3) proportional to the reciprocal of is called the α parameter.

In this case, a sufficient condition for stabilizing the characteristic equation expressed by the equation (1) is Some Sufficient Conditions f
or Stability and Instability of Continuous Liner S
tationary Systems (Automat. Remote Contr., Vol.39,
1285/1291: From AV Lipatov and NI Sokolov), it is derived as in equation (4) (see Fig. 3).

Α ⁱ <0.68 (i = 1, 2, 3, ..., N-1) (4)

Since the low-order α corresponds to the response mode on the low-order side of the characteristic equation, the low-order α (particularly α ⁱ )
Greatly affects the representative root that governs the representative response. α ⁱ
Reducing the value corresponds to preventing the overshoot with respect to the target value tracking by using the representative root as the real root.

Since the α parameter is represented by the control parameter and the parameter indicating the gas turbine characteristic, by setting the α parameter model (reference model) so as to have the response characteristic corresponding to the required specification, Control parameters are determined.

The change in the control characteristic due to the change in the characteristic of the gas turbine can be regarded as the change in the α parameter, and the deviation of each α parameter from the reference model set over the entire variation range of the gas turbine characteristic. By designing to be the minimum, it is possible to design a control system whose control performance is hard to change (robust) even when the gas turbine characteristics change.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a gas turbine to which the present invention is applied. Specifically, this gas turbine comprises a compressor 1, a combustor 2 and a turbine 3, and its control system is shown in FIG. The configuration is as shown.

The high-pressure air that has passed through the compressor 1 is introduced into the combustor 2, whose pre-combustion section is 400 ° C to 4 ° C.
After the temperature is raised to 50 ° C., it is mixed with the main fuel sent through the fuel control valve 5 immediately before the catalyst layer 4 and then passes through the catalyst layer 4. At this time, the mixed gas is mixed in the catalyst layer 4
It burns at a low temperature while causing a catalytic reaction by the activated catalyst of.

On the other hand, a bypass valve 6 is provided in order to control the catalyst outlet temperature of the catalyst layer 4, and a part of the high pressure air discharged from the compressor 1 passes directly through the bypass valve 6 to the turbine. 3 has a structure extending to the inlet of the turbine 3, and this air is mixed with the combustion gas passing through the catalyst layer 4 and introduced into the turbine 3.

In order to maintain the rotation speed of the turbine 3,
The temperature of the mixed gas (turbine inlet temperature) may be maintained at a certain value corresponding to the load. This can be controlled while maintaining the catalyst outlet temperature by adjusting the fuel flow rate and the bypass air flow rate.

In the control system of FIG. 2, the transfer function for rotation speed control is expressed by equation (5).

[0023] Here ^{A = (KN1 + K NP s} + K ND s 2) _{[K TI + K TP s + K} TD s 2) + K 1 (1 + T S s) (1 + T B s) s ] _{+ K 1 D (s) (} K TI _{+ K TP s + K TD s} 2) (1 + T F s) s + K 1 [A (s) (1 + T B s) -K TN B (s) ] _{(1 + T S s) (} 1 + T F s) s 2 (Ts: temperature Sensor delay time constant)

The gas turbine control device of the present invention is as follows.

From the characteristic equation of the equation (5), each α _i of the equation (3) is obtained, and the reference model (α parameter) is set so as to satisfy the required specifications.

When used as a gas turbine for power generation, since importance is attached to responsiveness to load disturbance, α _i is set to a slightly large value, and a change in the gas turbine characteristics (see FIG. 4) is taken into consideration. It is preferable that each α be uniformly set to 00.5 in consideration of 4).

In order to minimize the deviation from the reference model of each α parameter obtained in, in the entire range where the gas turbine characteristics fluctuate due to load fluctuations,
Find the control parameter that minimizes the evaluation function of Eq. (6).

J = Σ [log (α _i /0.5)] ² (6) By designing the control system by the above method, a robust control device in which the control performance does not easily change even when the load changes. Will be designed.

[0029]

As described in detail above, according to the present invention,
Various effects as described below can be obtained.

(1) Unlike conventional control devices such as control parameter compensation, which requires a large number of measurement points for accurate measurement, a control system can be configured with a small number of measurement points.
High reliability due to its simple structure.

(2) Since the control system is designed so as to have sufficient robust characteristics in the range where the gas turbine characteristics fluctuate, it is possible to deal with sudden changes in operating conditions with high reliability.

(3) Since the robust control device considers the variation range of the gas turbine characteristics, not only the robustness is unnecessarily enhanced, but also appropriate response characteristics can be secured.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a catalytic combustion type gas turbine to which the present invention is applied.

FIG. 2 is a block diagram showing a configuration of a control system of the gas turbine.

FIG. 3 is a diagram showing a pole existence range of a reference model in which an α parameter is constant.

FIG. 4 is a diagram showing a dynamic characteristic of a gas turbine, wherein FIG. 4 (a) shows a change in response characteristic due to a step input of a fuel control valve, and FIG. 4 (b) shows a gas due to a step input of a bypass valve. 4 shows changes in response characteristics of a turbine.

[Explanation of symbols]

 1 Compressor 2 Combustor 3 Turbine 4 Catalyst layer 5 Fuel control valve 6 Bypass valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Ogawa 1-1 Kawasaki-cho, Akashi-shi Kawasaki Heavy Industries Ltd. Akashi factory (72) Inventor Mitsugu Ashikaga 1-1 Kawasaki-cho Akashi-shi Kawasaki Heavy Industries Ltd. Akashi Factory

Claims (2)

[Claims] 1. When a characteristic equation of a transfer function of a control system is represented by the following equation (1), the following equation (3) including a coefficient of the following equation (2) which is a partial quadratic equation of the equation (1). A gas turbine control device having a transfer function in which a parameter defined by 1. 2. The gas turbine control device according to claim 1, wherein the predetermined value is 0.5.