RU2446298C1 - Gas turbine engine acs - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed system additionally comprises maximum signal selector, 3^rd comparator, coupling unit, switch and 2^nd adder. Note here that 1^st and 2^nd inputs of maximum signal selector are connected with 1^st and 2^nd inputs of minimum signal selector with its output connected with 2^nd input of 3^rd comparator. Output of 1^st comparator is connected with second input of second adder with its output connected to second input of second adder with its output connected to rotor rpm controller. Logical device output is connected with second input of the switch with its second output connected to second input of first adder.

EFFECT: adaptive control over various output coordinates by means of channel selector and signal self-tuning circuit, longer lifer of gas turbine engine.

2 dwg

Description

The invention relates to the field of automatic control systems (ACS) of a gas turbine engine (GTE).

Known self-propelled guns of gas turbine engines, in which, to eliminate the negative influence of the interaction of regulators on the characteristics of the control system with one regulating factor, gas turbine rotor speed and gas temperature meters, these parameters regulators, a minimum signal selector, and an actuator affecting fuel consumption are contained [1].

The disadvantage of this scheme is that the interaction of the control channels is maintained in transient modes. This self-propelled guns of a gas turbine engine has a low dynamic accuracy and temperature cast during selection, which can be explained as follows.

GTE has different dynamic characteristics for different output coordinates of the control object relative to fuel consumption.

Let us consider the self-propelled guns of a gas turbine engine as a two-dimensional object with one control action, in which an algebraic selector of the minimum signal is used. The first channel of this self-propelled guns is a control channel that determines the operation mode of the object by the output coordinate Y ₁ , its predetermined value Y ₁₀ depends on time. The second channel is the restriction channel, its predetermined value Y ₂₀ is constant and determines the maximum mode of operation of the object by the coordinate Y ₂ .

Transfer functions of the control object:

along the coordinate Y ₁ :

along the coordinate Y ₂ :

where p is the Laplace transform operator;

K ₁ , K ₂ - transmission coefficients;

A ₁ (p), A ₂ (p), B (p) are polynomials depending on the type of object.

Assume that the order A ₁ (p) is less than the order B (p), and the order A ₂ (p) is equal to the order B (p). Such a mathematical description is typical, for example, for the dynamic characteristics of a gas turbine engine in terms of rotor speed and gas temperature with a change in fuel consumption in the combustion chamber.

Transfer function of a common isodromic regulator

The transfer functions of the controller of the first - W ₁ (p) and the second - W ₂ (p) channels are selected based on the given requirements for the dynamic characteristics of each of them. This can be done as follows. We require that the transfer functions of individual open channels without taking into account the delay of the coordinate meters satisfy the equalities:

where W _m1 (p) and W _m2 (p) are the transfer functions of the reference models

open channels. Then

If the transfer functions of individual open channels are selected as

then, to obtain the required quality of regulation of the output coordinates, the regulators, according to (6) and (7), must have, for example, the following transfer functions:

At the same time, the inertia of the temperature sensor must be adjusted so that the parameter meters are inertialess.

As is known [2], the principle of selection is usually applied, according to which the gas-turbine engine parameter is regulated, which is closest to the value determined by the control program. Therefore, in order to obtain the required quality of regulation, the selector switchover must occur at the moment of equality of the mismatches between the current values of the output coordinates and their setting values, i.e. at the moment of equal signals in front of the regulators

The analysis shows that the gas temperature controller is inertial with respect to the gas turbine rotor speed controller; therefore, the selector switches from the channel of the rotor speed to the gas temperature channel with delay. As a result, the gas temperature is cast.

The closest technical result to be achieved, chosen for the closest analogue, is a gas turbine engine self-propelled guns containing control channels for rotor speed and gas temperature, a minimum signal selector, an actuator, two corrective links, two summing elements, a logic device (comparator) and a key [3 ].

In this self-propelled guns due to the inclusion of two cross corrective links with transfer functions

the setting action of the open channel of the gas temperature limitation occurs and the condition

when switching the self-propelled guns to the gas temperature limiting channel with equal signals at the inputs of the minimum signal selector

This allows you to get the required quality of the transition process according to the gas temperature when this channel is turned on.

The disadvantage of this self-propelled guns is that when you switch back from the gas temperature channel to the rotor speed channel, the structure, parameters of the correcting links and the place where the correcting signal is turned on must change, i.e. this system is not adaptive to a change in its structure when selecting channels and does not provide in this case the specified quality of transients.

The task to which the claimed invention is directed is to improve the dynamic characteristics of self-propelled guns by eliminating casts and ensuring a given quality of transients in the output coordinates of the gas turbine engine when the selector switches the various channels of the system forward and backward, which improves the quality of the control system and increases the life of the engine .

The solution to this problem is achieved by the fact that in the automatic control system of a gas turbine engine containing a rotor speed controller, a minimum signal selector, an isodrome controller, a gas turbine engine, a rotor speed meter and a first comparison element, a rotor speed controller, the output of which is connected to the second input of the first comparison element, a gas temperature meter connected in series, the second comparison element, the first summing electric an element, a gas temperature controller and a logic device, a gas temperature controller, the output of which is connected to the second input of the second comparison element, wherein the output of the rotor speed controller is connected to the second input of the logic device, the gas temperature controller output is connected to the second input of the minimum signal selector, and the second the output of the gas turbine engine is connected to the input of the gas temperature meter, in contrast to the prototype, series-connected maximum signal selectors are additionally introduced , a third comparison element, a matching unit, a switch and a second summing element, wherein the first and second inputs of the maximum signal selector are connected respectively to the first and second inputs of the minimum signal selector, the output of which is connected to the second input of the third comparison element, the output of the first comparison element is connected to the second the input of the second summing element, the output of which is connected to the input of the rotor speed controller, the output of the logic device is connected to the second input of the switch, th output is connected to the second input of the first summing element.

The essence of the system is illustrated by drawings. Figure 1 presents a block diagram of an automatic control system for a gas turbine engine; figure 2 - the results of the simulation of transients in the ACS of the gas turbine engine with various channel changes by the minimum signal selector:

a) from the channel of the rotor speed to the channel of the gas temperature, b) from the channel of the gas temperature to the channel of the rotor speed, with and without an adaptation circuit, while the GTD output coordinates are presented in relative form

The automatic control system of a gas turbine engine contains a series-connected rotor speed controller 1, a minimum signal selector 2, an isodrome controller 3, a gas turbine engine 4, a rotor speed meter 5 and a first comparison element 6, a rotor speed controller 7, the output of which is connected to the second input the first comparison element 6, the gas temperature meter 8 connected in series, the second comparison element 9, the first summing element 10, the gas temperature regulator 11 and the log a device 12, a gas temperature adjuster 13, the output of which is connected to the second input of the second comparison element 9, the output of the rotor speed regulator 1 being connected to the second input of the logic device 12, the output of the gas temperature regulator 11 being connected to the second input of the minimum signal selector 2, and the second output of the gas turbine engine 4 is connected to the input of the gas temperature meter 8, while the system additionally contains series-connected selector of the maximum signal 14, the third comparison element 15, bl ok coordination 16, the switch 17 and the second summing element 18, and the first and second inputs of the maximum signal selector 14 are connected respectively to the first and second inputs of the minimum signal selector 2, the output of which is connected to the second input of the third comparison element 15, the output of the first comparison element 6 is connected with the second input of the second summing element 18, the output of which is connected to the input of the speed controller of the rotor 1, the output of the logic device 12 is connected to the second input of the switch 17, the second output is cerned connected to the second input of the first summing element 10.

The automatic control system of a gas turbine engine operates as follows.

In the channel for regulating the rotor speed of the turbine engine 4, the signal from the rotor speed meter 5, proportional to the rotor speed, is supplied to the first comparison element 6, where it is compared with the output signal of the rotor speed setter 7 and an output error signal E ₁ is generated, which is proportional to the speed deviation rotor from the set value. This signal through the second summing element 18 is fed to the input of the speed controller of the rotor 1, the output of which U _{1 is} connected to the first input of the minimum signal selector 2.

In the gas temperature control channel of the gas turbine engine 4, the signal from the gas temperature meter 8, proportional to the gas temperature, is supplied to the second comparison element 9, where it is compared with the output signal of the gas temperature setter 7 and an output mismatch signal E ₂ is generated, which is proportional to the deviation of the gas temperature from the set value. This signal through the first summing element 10 is fed to the input of the gas temperature controller 11, the output of which U _{2 is} connected to the second input of the minimum signal selector 2.

The output signal selector minimum signal 2 passes the output signal

the control channel, which currently requires less fuel consumption under the terms of the gas turbine engine. The signal from the selector of the minimum signal 2 through the isodromic regulator 3, which performs the function of the actuator, changes the fuel consumption in the combustion chamber of the gas turbine engine 4.

The output signals of the rotor speed controller 1 U ₁ and the gas temperature controller 11 U ₂ are fed to the inputs of the maximum signal selector 14, at the output of which a signal is generated

The output of the third comparison element 15 determines the difference of the signals at the output of the regulators

where U _zam - the output signal of the closed-loop controller;

U _times - the output signal of the open channel regulator.

The output signals U ₁ and U ₂ also go to the input of the logical device 12, the output of which is formed by a logical signal L, which defines the closed channel of the ACS

The output signal ε of the third comparison element 15 through the matching unit 16 and the switch 17 is input to the corresponding open-loop controller using the first 10 or second 18 summing element, which is determined by the state of the switch 17 in accordance with the logical signal L of the logical device 12. Since ε is less zero, then this signal reduces the driving effect of the open channel and thereby corrects the moment of switching channels.

As noted above, the speed controllers of the rotor 1 and the gas temperature 11 have different dynamic characteristics, as a result of which the condition for switching the selector of the minimum signal 2

differs from the necessary reference condition for switching the ACS - equality of mismatches between the current values of the output coordinates and their defining effects

Therefore, coordination of these conditions is necessary. As is known [4], coordination of the behavior of individual ACS channels is possible due to the control loop of their relative motion. In this case, it is ensured by introducing a signal self-tuning circuit according to the difference of the signals ε at the output of the regulators with the action of the open channel of the system acting on the driving effect. This allows you to build self-propelled guns gas turbine engine, adaptive to a change in its structure when switching channels with a selector.

Let the channel for controlling the rotor speed be closed, i.e. first channel. Then, the output of the signal self-tuning circuit is switched on by means of the first summing element 10 to the input of the gas temperature controller 11 of the second open channel.

The signal at the output of the rotor speed controller

Signal at the output of the gas temperature controller

where W _c (p) is the transfer function of the matching block 16.

Then the difference of the signals at the output of the regulators

For W _c (p) equal to K and K sufficiently large, we obtain

ε → 0; U ₂ → U ₁ ,

or

where m is a sufficiently small quantity.

Thus, due to the operation of the signal self-tuning circuit, the moment of switching the minimum signal selector 2

approaching the condition of channel switching by channel errors

This, accordingly, allows to eliminate casting and ensure the necessary quality of the transition process when the gas temperature controller 11 is closed and the regulator is turned on. When U ₁ is equal to U ₂ , the channels are switched, and then when U ₁ is greater than U ₂ , - change in the state of the channels: the first channel becomes open, and the second channel becomes closed. This also leads to a change in the structure of the self-tuning loop.

Similar processes are typical for self-propelled guns and when the selector is switched from a closed channel of gas temperature to the channel of the rotor speed. In this case, the output signal of the self-tuning circuit is switched on with the switch 17 and the second summing element 18 to the input of the speed controller of the rotor 1, changing the driving effect of the first channel.

Since the order of the denominators of the transfer functions of the individual regulators W ₁ (p) and W ₂ (p) of a two-shaft gas-turbine engine is not higher than two, the self-tuning circuit provides a good quality of transients at sufficiently high values of the transfer coefficient K.

The simulation results of the considered self-propelled guns of the gas turbine engine, shown in figure 2, with the setting actions of the channels

and the fulfillment of conditions (8) show that with direct and reverse switching of channels by a selector, the quality of transients of a switched channel is significantly improved with the introduction of a self-tuning circuit. Self-propelled guns maintains the specified quality when changing the structure, i.e. is adaptive.

So, the claimed invention allows for adaptive control of various output coordinates of the gas turbine engine using a channel selector and a signal self-tuning circuit. The casting of the output coordinates of the engine is eliminated, the specified quality of transients of the included channel of the system is ensured, which contributes to an increase in the resource of the gas turbine engine.

Sources of literature

1. Integrated systems for automatic control of aircraft power plants. / Ed. A.A.Shevyakova. - M.: Mechanical Engineering, 1983.- 283 p., P. 126, Fig. 3.26.

2. Integrated systems for automatic control of aircraft power plants. / Ed. A.A.Shevyakova. - M.: Mechanical Engineering, 1983.- 283 p., P. 110.

3. Certificate of the Russian Federation No. 2416 for a utility model. IPC 6 F02C 9/28. System for automatic regulation of a gas turbine engine. / V.I. Petunin, A.I. Frid, V.V. Vasiliev, F.A. Shaimardanov. Application No. 95108046; declared 05/18/95; publ. 07/16/96; Bull. Number 7.

4. Miroshnik IV Coordinated management of multi-channel systems. - L.: Energoatomizdat, 1990 .-- 128 p., P. 21, fig. 1.8.

Claims (1)

An automatic control system for a gas turbine engine, comprising a rotor speed controller, a minimum signal selector, an isodromic regulator, a gas turbine engine, a rotor speed meter and a first comparison element, a rotor speed controller, the output of which is connected to the second input of the first comparison element, in series gas temperature meter, second comparison element, first summing element, gas temperature controller and logic a device, a gas temperature adjuster, the output of which is connected to the second input of the second comparison element, the output of the rotor speed controller being connected to the second input of the logic device, the gas temperature controller output being connected to the second input of the minimum signal selector, and the second output of the gas turbine engine connected to the meter input gas temperature, characterized in that it further comprises a series-connected selector of the maximum signal, a third comparison element, a matching unit, ne a switch and a second summing element, wherein the first and second inputs of the maximum signal selector are connected respectively to the first and second inputs of the minimum signal selector, the output of which is connected to the second input of the third comparison element, the output of the first comparison element is connected to the second input of the second summing element, the output of which is connected to the input of the rotor speed controller, the output of the logic device is connected to the second input of the switch, the second output of which is connected to the second input of the of the total summing element.

Images