JPH073190B2 - Gas turbine controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a gas turbine provided with a variable nozzle, and more particularly, to improving durability of a variable nozzle portion,
The present invention relates to technology for improving control reliability.

<Prior Art> As a conventional control apparatus for this type of gas turbine, there is a conventional control apparatus as shown in FIGS. 6 and 7, for example (reference: SAE 720168 "THE FORD TURBINE AN ENGINE DWSIGN
ED TO COMPETE WITH THE DIESEL "," GAS TURBINE INTER
NATIONAL 1970 JULY-AUGUST P15 "FORD GOES TO ELECTRO
NIC CONTROL FORMAX RELIABILITY AND ECONOMY ”).

To explain the outline of this, the compressor 1 is connected to a compressor turbine 3 by a gas generator shaft 2, and the power turbine 4 is connected to a generator 5 as a load via a gear box 6.

The atmosphere is compressed by the compressor 1, heated through the heat exchanger 7, and then reaches the combustor 8.

On the other hand, after the fuel is metered from the fuel pump 9 through the fuel regulating valve 10, the fuel is mixed with the compressed and heated air in the combustor 8 and burned, and the combustion gas enters the compressor turbine 3 and the compressor turbine 3 3 and the compressor 1 are driven to rotate. The fuel control valve 10 is driven by a valve drive mechanism 11, which controls the fuel flow rate.

The fuel gas discharged from the compressor turbine 3 enters the power turbine 4 via the variable nozzle (guide vanes) 12 to drive the power turbine 4 to rotate, and then passes through the heat exchanger 7 to heat the compressed air as described above. And then discharged.
The generator 5 is rotationally driven by the rotation of the power turbine 4.

The device 20 for controlling this system receives signals from the gas generator shaft speed detector 13, the power turbine speed detector 14, the compressor inlet temperature detector 15, the compressor turbine inlet temperature detector 16, and the load detector 17. It is input and the drive amounts of the valve drive mechanism 11 and the variable nozzle 12 are controlled by each circuit described later.

The target gas generator shaft speed calculation circuit 20A obtains the target gas generator shaft speed N _ggSET based on the load L _PT of the generator 7 and the compressor inlet temperature T _1, and the fuel flow control circuit 20B uses the target gas generator. Speed N
Fuel flow rate G supplied to the combustor 8 in order to match _ggSET with the actual rotation speed N _gg of the gas generator shaft 2.
_fSET is calculated by PID feedback control, and the control signal is output to the valve drive mechanism 11.

On the other hand, the variable nozzle angle calculation circuit 20C determines the target rotation speed N of the output shaft of the power turbine 4 corresponding to the power generation frequency.
A control signal calculated by the PID feedback control of the set value θ _VNSET of the variable nozzle angle is output to the variable nozzle 12 in order to match _PTSET with the actual rotation speed N _PT .

Further, when the compressor turbine inlet temperature T ₂ exceeds a predetermined limit temperature, the emergency stop circuit 20D outputs a signal of the fuel flow rate G _fSET = 0 to the fuel flow rate control circuit 20B to stop the fuel supply, A variable set angle θ _VNO signal is output to the variable nozzle angle calculation circuit 20C to control the variable nozzle 12 angle to the set angle θ _VNO .

<Problems to be Solved by the Invention> However, in such a conventional gas turbine control device, the constant rotation control performance of the power turbine is high when a large change in the load occurs, such as when a large load is turned on or off. In order to ensure good control of the variable nozzle angle, it is necessary to sufficiently increase the control gain in the PID feedback control of the variable nozzle angle. However, at that time, the variable nozzle causes the influence of noise and oscillation, as shown in FIG. It constantly vibrates in small increments.

Since the variable nozzle is installed in a high temperature portion, durability will be significantly deteriorated if the small vibration as described above continues to occur.

Further, when an abnormality occurs in the means for detecting the magnitude of the load L _PT (hereinafter simply referred to as load), the fuel flow rate and the variable nozzle angle are controlled based on the detected value of the abnormal load, which is fatal. It causes the trouble of the proper control.

The present invention has been made in view of such conventional problems, and provides a gas turbine control device that solves the above problems by selectively using two types of control depending on whether there is an abnormality in load detection. With the goal.

<Means for Solving the Problems> Therefore, according to the present invention, as shown in FIG. 1, a compressor turbine in which gas compressed by a compressor is burned by a combustor and then connected to the compressor via a gas generator shaft. To drive the compressor and the compressor turbine to rotate, and to supply the gas passed through the compressor turbine to the power turbine through the variable nozzle to drive the power connected to the power turbine and the power turbine to rotate the load. In a control device for a gas turbine, the load detecting means for detecting the magnitude of the load and a gas generator shaft target rotation speed setting for setting a target rotation speed of the gas generator shaft based on the detected load magnitude. And a gas generator for detecting the rotation speed of the gas generator shaft. Generator shaft rotation speed detection means, fuel flow rate control means for controlling the fuel flow rate to the combustor so that the rotation speed of the gas generator shaft approaches the target rotation speed, and based on the detected load magnitude, Basic control angle setting means for setting a basic control angle of a variable nozzle, output shaft rotation speed detection means for detecting the rotation speed of the output shaft, and the variable nozzle so that the rotation speed of the output shaft approaches a target rotation speed. Variable nozzle angle control means for feedback-correcting and controlling the angle of the above with respect to the set basic control angle, and the first variable nozzle angle so that the rotation speed of the output shaft approaches the target rotation speed. Second variable nozzle angle control for feedback-correcting and controlling the angle of the variable nozzle with a control gain larger than that of the control means Stage, an abnormality detecting means for detecting the presence or absence of abnormality of the load detecting means, and when the load detecting means is detected to be normal, the gas generator shaft target rotation speed setting means sets the gas generator shaft When the target rotation speed is output to the fuel flow rate control means and the first variable nozzle angle control means is operated, and it is determined that the load detection means is abnormal, the fuel flow rate control means controls the gas generator shaft of the gas generator shaft. A control switching means for applying a signal of the target rotation speed set for emergency and for activating the second variable nozzle angle control means is provided.

<Operation> When the abnormality detection means detects that the load detection means is normal, the target rotation speed of the gas generator shaft set by the gas generator shaft target rotation speed setting means by the control switching means is supplied to the fuel flow rate control means. At the same time as the output, the first variable nozzle angle control means is activated.

In this case, the gas generator shaft target rotation speed setting means sets the target rotation speed of the gas generator shaft based on the magnitude of the load detected by the load detection means, and the fuel flow rate control means is set by the gas generator shaft rotation speed detection means. The fuel flow rate to the combustor is controlled so that the detected actual rotation speed of the gas generator shaft approaches the target rotation speed set by the gas generator shaft target rotation speed setting means.

The first variable nozzle angle control means controls the angle of the variable nozzle by feedback-correcting the basic control angle set by the basic control angle setting means based on the magnitude of the load, thereby controlling the output shaft of the power turbine. The control is performed to bring the rotation speed of 1 closer to the target rotation speed.

Therefore, even when a large load changes such as when a large load is turned on or off, the basic control angle changes stepwise according to the change in the load, so the angle of the variable nozzle also changes stepwise with good responsiveness. , Fine feedback control is performed with a small control gain to control the output shaft to the target rotation speed with respect to the initial angle.

On the other hand, when the abnormality detecting means detects an abnormality in the load detecting means, the control switching means gives the fuel flow rate controlling means a signal indicating the emergency target rotational speed of the gas generator shaft and the second variable nozzle angle controlling means. Is activated. As a result, the fuel flow rate control means controls the fuel flow rate so that the rotation speed of the gas generator shaft approaches the target rotation speed for emergency.

Further, the second variable nozzle angle control means feedback-controls the output shaft to the target rotation speed with a control gain larger than that of the first variable nozzle angle control means from the angle of the variable nozzle before the abnormality detection. Therefore, even if the load cannot be detected normally, the output shaft quickly converges to the target rotation speed.

<Examples> Examples of the present invention will be described below with reference to the drawings. However, the configuration other than the control unit is the same as that in FIG. 5, but a compressor inlet pressure detector 18 and a variable nozzle angle detector 19 shown by the chain line in the figure are provided. Other components will be described using the reference numerals in the figure.

FIG. 2 shows each control unit of the control circuit in the control device for a gas turbine according to the present invention, and the control operation by the control circuit will be described with reference to the flowchart of FIG.

In step (FIG. 3 referred to as S in) 1 is calculated as described later correction value of the correction value N _gg ^* and the load L of the gas generator shaft rotation speed N _gg L ^*.

That is, the corrected gas generator shaft rotation speed calculation unit 31 calculates the rotation speed N _gg of the gas generator shaft 2 detected by the gas generator shaft rotation speed detector 13 serving as the gas generator shaft rotation speed detection means from the compressor inlet temperature detector. 1
5 by calculating the corrected values N _gg ^* the temperature T ₁ of the been compressor 1 inlet detection.

Further, the corrected load calculation unit 32 obtains a value L ^* obtained by correcting the load L detected by the load detector 17 as a load detecting means by the pressure P ₁ at the compressor 1 inlet detected by the compressor inlet pressure detector 8. Calculate

These corrections are made to compensate for the large change in the output state of the power turbine depending on the inlet state of the gas turbine, and the calculation formula (T
₀₀ and _P00 are corrected by the reference value).

In step 2, the presence or absence of abnormality (failure) in the load detector 17 is input with the load L detected by the load detector 17 and the temperature T ₂ of the compressor turbine 3 inlet detected by the compressor turbine inlet temperature detector 16. The abnormality determination unit 49 determines. The abnormality determination unit 49 corresponds to abnormality detecting means.

This is performed in accordance with a subroutine as shown in FIG. 4, which corresponds to the disconnection and the incorrect wiring which are most likely to occur.

In step 21, when the load is outputting an abnormal signal out of the range of 0 to the rated load, it is judged to be abnormal in step 22, and if not, the process proceeds to step 23, after the load becomes zero. If the compressor turbine inlet temperature T ₂ exceeds the predetermined value T ₂₀ after the predetermined time t ₀ , it proceeds to step 22 and is judged to be abnormal, otherwise it proceeds to step 24 and becomes normal. It is determined that

After the presence or absence of abnormality of the load detector 17 is determined by such a subroutine, the process proceeds to step 3 in FIG. 3, and the set value switching section 34 will be described later according to the signal from the control switch 50 based on the determination result. Switch the target gas generator shaft speed setting.

That is, when it is determined that the load detector 17 is normal, the routine proceeds to step 4, where the target gas generator shaft speed setting unit 33 searches the map based on the correction value L ^* for the target gas generator shaft speed N. _{When gg} ^* _SET is selected and the load detector 17 is abnormal, the _routine proceeds to step 5, where the emergency target gas generator shaft speed N _gg ^* _SETC set by the emergency target gas generator shaft speed setting unit 35 is selected. It is output to the subtractor 36. Therefore, the control switch
The set value switching unit 34 together with 50 constitutes a part of the control switching means. Here, the target gas generator shaft speed for emergency
As N _gg ^* _SETC , the maximum value of N _gg ^* _SET may be set.

Next, in step 6, the control gain calculator 37 calculates the control gain based on the modified value N _gg ^* .

In step 7, the subtractor 36 _{calculates the} corrected value N from the target gas generator shaft rotation speed (N _gg ^* _SET , N _gg ^* _SETC ).
_Based on the rotation speed deviation amount obtained by subtracting _{gg *} and the calculated control gain, the fuel flow rate feedback control unit 38 supplies the fuel flow rate G supplied to the combustor 8 so that the rotation speed deviation amount approaches 0. Calculated by _fSET PID feedback control, and calculated fuel flow rate G in step 8.
A control signal corresponding to _fSET is output to the valve drive mechanism 11. The fuel flow rate is controlled to the control value by the fuel control valve 10 driven via the valve drive mechanism 11. That is, the functions of steps 7 and 8 by the calculator 36, the control gain calculator 37, the fuel flow rate feedback controller 38, the valve drive mechanism 11 and the fuel adjusting valve 10 correspond to the fuel flow rate control means.

Following the fuel flow rate control, the angle of the variable nozzle 12 is controlled.

In step 9, as in step 3, the set value switching part 42 and the control gain switching part 44 control the variable nozzle angle in accordance with a signal from the control switching device 50 based on the abnormality determination result of the load detector 17, as described later. Switch over. Therefore, the set value switching unit 42 and the control gain switching unit 45 form a part of the control switching means.

That is, when the load detector 17 is normal, the process proceeds to step 10 and the basic control angle calculation unit as the basic control angle setting means.
The value calculated by calculating the basic control value θ _VNSETFF of the variable nozzle angle corresponding to the load correction value L ^* by 41 is the set value _switching unit 4
It is output to the adder 43 via 2.

In step 11, the control gain for the variable nozzle angle θ _VN detected by the variable nozzle angle detector 19 is controlled by the value calculated by the first control gain calculation unit 44 using the correction value N _gg ^* of the gas generator shaft rotation speed as a parameter. It outputs to the nozzle angle feedback control unit 46 via the gain switching unit 45.

Next, in step 12, the subtractor 47 sets the target rotational speed _{NPTSET of the} power turbine preset according to the load.
From the rotational speed deviation by subtracting the power turbine rotational speed N _PT detected by the power turbine rotational speed detector 14, from the nozzle gain feedback control unit 46 using the calculated control gain of the variable nozzle angle by PID control _{Calculate the} feedback control value θ _VNSETC .

In step 13, the adder 43 obtains a control value θ _VNSET by adding the calculated target variable nozzle angle θ _VNSETFF and the feedback control amount θ _VNSETC .

In step 14, the calculated control value θ _VNSET of the variable nozzle angle is output to the variable nozzle 12. That is, the basic control angle calculation unit 41, the first control gain calculation unit 44, the subtractor 47, the nozzle angle feedback control unit 46, and the adder 4
The functions from step 10 to step 14 by 3 correspond to the first variable nozzle angle control means.

On the other hand, when the load detector 17 is determined to be abnormal, the step
Proceeding to step 15, the control gain for the variable nozzle angle θ _{VN is} calculated by the second control gain calculation unit 48 using the correction value N _gg ^* of the gas generator shaft speed as a parameter, and the value obtained through the control gain switching unit 45 is used as the nozzle angle. Output to the feedback control unit 46.

Here, the arithmetic expression of the second control gain calculation unit 48 is set so that the control gain is sufficiently larger under the same condition than the control gain calculated by the first control gain calculation unit 44.

In step 16, the feedback control value θ of the variable nozzle angle is controlled by PID control in the nozzle angle feedback control unit 46 using the rotational speed deviation of the power turbine and the control gain calculated by the second control gain calculation unit 48.
_{Calculate VNSETC} .

In step 17, the setting value switching unit 42 cuts off the output of the basic control angle signal calculated by the basic control angle calculation unit 41 to the adder 43, thereby the feedback control value θ _{VNSETC of the} calculated variable nozzle angle. Is directly set as the control value θ _VNSET of the variable nozzle angle.

When the control value θ _VNSET is set in step 14, the variable nozzle 12
Is output to. That is, the second control gain calculator 48 and the subtractor 4
7. The functions from step 15 to step 17 and step 14 by the nozzle angle feedback control unit 46 and the adder 43 correspond to the second variable nozzle angle control means.

With such a configuration, when the load detector 17 is normal, the feedback control of the gas generator shaft speed by the fuel flow rate control according to the detected value of the load and the feedback control of the power turbine speed by the control of the variable nozzle angle are performed. Done.

Particularly in the latter feedback control, the basic control value of the variable nozzle angle according to the value of the load is obtained, and this value is feedback-corrected, so that the control gain of the feedback control can be set small.

Therefore, even when the load changes greatly such as when a large load is turned on or off, the control responsiveness can be sufficiently improved as shown in FIG. 5, and the occurrence of small vibrations of the variable nozzle 12 can be suppressed. The durability can be improved as much as possible.

On the other hand, when the load detector 17 is abnormal, the gas generator shaft is feedback-controlled using the emergency target rotation speed, and the basic control angle of the variable nozzle based on the load detection value is not used, and is larger than the normal time. The rotation speed of the power turbine is feedback-controlled by controlling the variable nozzle angle using the control gain.

As a result, it is possible to prevent the rotation speed of the gas generator shaft from being controlled to an abnormal rotation speed based on the detected value of the abnormal load, and it is possible to control to an emergency set value. Also, when the load detection value is abnormal, the basic control angle of the variable nozzle is not reliable, so if the same control as in the normal state is performed, it will take a lot of time to converge the power turbine to the target speed. However, in such an abnormal situation, the power turbine can be quickly brought close to the target speed by feedback-correcting the current value without using the basic control value with a large control gain. .

By these emergency fuel flow rate control and variable nozzle angle control, even when the load detector 17 is abnormal, it can be sufficiently dealt with.

<Effects of the Invention> As described above, according to the present invention, the control system of the fuel flow rate control and the variable nozzle angle control is appropriately switched according to the presence or absence of abnormality of the load detection means, so that it is high in a normal state. The control performance and the durability of the variable nozzle can be ensured, and the operation can be continued while maintaining the highest control performance even in the event of an abnormality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention, FIG. 2 is a block diagram showing a configuration of a control unit of an embodiment of the present invention, FIG. 3 is a flowchart showing a control routine of the same embodiment, and FIG. 5 is a flowchart showing a load detector abnormality determination subroutine in the same control routine, FIG. 5 is a time chart showing the state of each part during control of the same embodiment, and FIG. 6 is a gas turbine common to the above embodiment and conventional example. FIG. 7 is a block diagram showing the configuration of the control unit of the conventional example, and FIG. 8 is a block diagram showing the configuration of the control unit of the conventional example. 1 ... Compressor, 2 ... Gas generator shaft, 3
...... Compressor turbine, 4 …… Power turbine,
5 ... Generator, 8 ... Combustor, 10 ... Fuel adjustment valve, 11 ...
… Valve drive mechanism, 12 …… Variable nozzle, 13 …… Gas generator shaft speed detector, 14 …… Output shaft detector, 17…
… Load detector, 33 …… Target gas generator shaft speed setting part, 34 …… Set value switching part, 35 …… Emergency target gas generator shaft speed setting part, 36 …… Subtractor, 37 …… Control gain Calculation unit, 38 ... Fuel flow rate feedback control unit, 41
…… Basic control angle calculation unit, 42 …… Set value switching unit, 43 ……
Adder, 44 ... First control gain calculation unit, 45 ... Control gain switching unit, 46 ... Nozzle angle feedback control unit, 47
…… Subtractor, 48 …… 2nd control gain calculation part, 49 …… Abnormality judgment part, 50 …… Control switch

Claims (1)

[Claims] 1. A gas compressed by a compressor,
After combustion by a combustor, the compressor and the compressor turbine are connected to the compressor via a gas generator shaft to drive the compressor and the compressor turbine in rotation, and the gas that has passed through the compressor turbine is supplied to the power turbine through a variable nozzle. In a control device for a gas turbine, in which a power turbine and a load connected to an output shaft of the power turbine are rotatably driven, load detecting means for detecting the magnitude of the load, and the detected magnitude of the load Gas generator shaft target rotation speed setting means for setting the target rotation speed of the gas generator shaft, gas generator shaft rotation speed detection means for detecting the rotation speed of the gas generator shaft, and the target rotation speed of the gas generator shaft. Fuel to the combustor to approach the number And fuel flow control means for controlling the amount,
Basic control angle setting means for setting a basic control angle of the variable nozzle based on the magnitude of the detected load, output shaft rotation speed detection means for detecting the rotation speed of the output shaft, and rotation of the output shaft. First variable nozzle angle control means for feedback-correcting and controlling the angle of the variable nozzle with respect to the set basic control angle so that the number of rotations approaches the target rotation speed, and the rotation speed of the output shaft is set to the target rotation speed. A second variable nozzle angle control means for feedback-correcting and controlling the angle of the variable nozzle with a control gain larger than that of the first variable nozzle angle control means so as to approach the number, and whether or not there is an abnormality in the load detection means. When the abnormality detecting means for detecting the load and the load detecting means are detected to be normal, the gas generator shaft target rotation is detected. When the target rotational speed of the gas generator shaft set by the setting means is output to the fuel flow rate control means and the first variable nozzle angle control means is operated, and it is determined that the load detection means is abnormal, Control switching means for providing the fuel flow rate control means with a signal of the target rotational speed set for emergency of the gas generator shaft and for activating the second variable nozzle angle control means. Gas turbine control device.