CN111830943B - Method for identifying faults of electric actuator of gas turbine - Google Patents

Method for identifying faults of electric actuator of gas turbine Download PDF

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CN111830943B
CN111830943B CN202010733536.XA CN202010733536A CN111830943B CN 111830943 B CN111830943 B CN 111830943B CN 202010733536 A CN202010733536 A CN 202010733536A CN 111830943 B CN111830943 B CN 111830943B
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fault
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observer
electric actuator
gas turbine
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CN111830943A (en
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张文广
汪洋
沈炀智
李浩瀚
贺东旭
王玮
田文利
刘延泉
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North China Electric Power University
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B23/00—Testing or monitoring of control systems or parts thereof
    • G05B23/02—Electric testing or monitoring
    • G05B23/0205—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults
    • G05B23/0259—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterized by the response to fault detection
    • G05B23/0262—Confirmation of fault detection, e.g. extra checks to confirm that a failure has indeed occurred

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Abstract

The invention discloses a fault identification method of a gas turbine electric actuator, belonging to the technical field of fault detection of a gas turbine control system, comprising the following steps: determining a nonlinear model of the electric actuator; adding a non-linear component to an observer; calculating a residual signal; determining a relationship between the residual signal and the fault; the invention introduces feedback proportional to the residual error, ensures that the observer is in a sliding mode, and carries out fault estimation. The method can detect and accurately estimate the real-time value of the fault, does not need to use an additional sensor to measure all elements of the state vector of the gas turbine electric actuator, and lays a foundation for developing fault identification research of the gas turbine electric actuator; the method has very important practical significance for theoretical research and engineering application of fault identification of the actuator of the gas turbine control system.

Description

Method for identifying faults of electric actuator of gas turbine
Technical Field
The invention belongs to the technical field of fault detection of gas turbine control systems, and particularly relates to a fault identification method of a gas turbine electric actuator.
Background
The gas turbine uses continuously flowing gas as a working medium to drive the impeller to rotate at a high speed, converts the energy of fuel into useful work, and is complex power equipment. Although the gas turbine has a series of advanced technical characteristics of quick start, low noise, small volume, high power and the like, the gas turbine has a complex structure and is easy to have various faults when working in a high-temperature and high-pressure severe environment. Statistically, 80% of gas turbine control system failures are caused by actuators or sensors. The electric actuator is used as an execution unit widely applied to the gas turbine, is convenient to take and use energy, is rapid in signal transmission, but is complex in structure and poor in explosion-proof performance. Therefore, whether the electric actuator can work normally is important for the operation of the unit and the safety of personnel. At present, domestic related research mainly focuses on the aspects of state monitoring and fault diagnosis of a gas turbine body, and the theoretical research and the engineering application aiming at fault identification of an actuator of a gas turbine control system are insufficient. Therefore, the development of the fault identification research of the gas turbine electric actuator has great practical significance.
Disclosure of Invention
The invention provides a fault identification method of an electric actuator of a gas turbine, which comprises the following steps: determining a nonlinear model of the electric actuator; adding a non-linear component to an observer; calculating a residual signal; determining a relationship between the residual signal and the fault; introducing feedback proportional to the residual; ensuring that the observer is in a sliding mode and performing fault estimation; the nonlinear model of the gas turbine electric actuator is characterized in that:
Figure BDA0002604112440000021
wherein x is a state vector of the electric actuator; y is a vector of state variables measured by the sensors; u is a control signal; f is the fault vector; a is a system dynamics matrix; b is a gain vector of the control signal; c is a vector that determines the nonlinear part of the system; d is an output matrix connecting the state vector and the measurement vector; e is the fault matrix for the fault location.
The vectors and matrices in the above formula are:
Figure BDA0002604112440000022
Figure BDA0002604112440000023
Figure BDA0002604112440000024
Figure BDA0002604112440000031
in the formula, theta b Is the angle, rad, of the reducer output shaft;
Figure BDA0002604112440000032
is the rotating speed of the output shaft of the reducer, r/s;
θ t is the angle of the motor rotor, rad;
Figure BDA0002604112440000033
is the rotational speed of the motor rotor, r/s; i is the current, A; k is the armature inductance, H; i is a reduction ratio; l r Is the back EMF coefficient, Vs/rad; l n Is the viscous friction coefficient of the reducer, Nms/rad; l h Is the viscous friction coefficient of the motor, Nms/rad; l v Is the torque coefficient, Nm/A; k is a radical of bg Is the dry coefficient of friction, Nm, of the retarder; k is a radical of tg Is the dry coefficient of friction, Nm, of the motor; sign is a sign function; j is the moment of inertia of the motor shaft, kg.m 2 (ii) a R is stator resistance, Ω; m is the actuator output shaft torque, Nm; w is the stiffness coefficient of the mechanical transmission, N/m.
The observer is as follows:
Figure BDA0002604112440000034
in the formula (I), the compound is shown in the specification,
Figure BDA0002604112440000035
is the state vector of the observer;
Figure BDA0002604112440000036
is the output signal of the observer;
Figure BDA0002604112440000037
is the dynamics matrix of the observer;
Figure BDA0002604112440000038
is a control signal;
Figure BDA0002604112440000039
is a vector connecting the state vector and the output signal;
Figure BDA00026041124400000310
is a vector containing the nonlinear part of the system in the observer; q is a matrix using state variables in the observer; h (r) is a feedback vector; r is a residual signal.
In the case of no fault, the following conditions must be met:
Figure BDA00026041124400000311
in the formula (I), the compound is shown in the specification,
Figure BDA00026041124400000312
is a matrix connecting the state vectors of the actuator and the observer; ε is the vector that provides the linkage for the state vectors of the actuator and observer.
The residual error r representing whether a fault exists in the electric actuator is as follows:
Figure BDA0002604112440000041
determining a relationship between residual error and fault, order
Figure BDA0002604112440000042
The following can be obtained:
Figure BDA0002604112440000043
introducing a feedback proportional to the residual error for fault estimation:
Figure BDA0002604112440000044
In the formula, a 1 Is a vector
Figure BDA0002604112440000045
The corresponding element of (1); j is a function of m Is a vector
Figure BDA0002604112440000046
The mth element of (1); f. of n Is the corresponding fault value; c. C m Is a vector
Figure BDA0002604112440000047
The corresponding element of (1); h is m (r) is the corresponding element of the feedback vector h (r).
The corresponding elements of the feedback vector are:
Figure BDA0002604112440000048
in the formula o m Is a positive coefficient, a s Is a vector
Figure BDA0002604112440000049
The corresponding elements of (1).
For the sliding mode, let
Figure BDA00026041124400000410
The following can be obtained:
Figure BDA00026041124400000411
in the formula (I), the compound is shown in the specification,
Figure BDA00026041124400000412
and
Figure BDA00026041124400000413
are the first and second derivatives of the residual signal.
The following conditions are satisfied when the above formula is satisfied:
Figure BDA0002604112440000051
Figure BDA0002604112440000052
in the formula, b nmax Is b n Maximum value of (d); c. C mmax Is c m Is measured.
The fault estimation is carried out by calculating a corresponding fault value f n Carrying out the following steps:
Figure BDA0002604112440000053
in the formula, h eq Is the signal h m Average value of sign (T). The failure value is related to the failure reason, failure location, failure time and other factors.
The invention has the advantages that the invention can effectively detect and estimate the fault value; all elements of the state vector of the gas turbine electric actuator are measured without using an additional sensor, so that a foundation is laid for developing fault identification research of the gas turbine electric actuator; the method has very important practical significance for theoretical research and engineering application of fault identification of the actuator of the gas turbine control system.
Drawings
FIG. 1 is a flow chart of the gas turbine electric actuator fault identification;
Fig. 2 is an effect diagram of fault identification of the gas turbine electric actuator.
Detailed Description
The invention provides a method for identifying faults of an electric actuator of a gas turbine, and the invention is described in detail by combining the accompanying drawings and an embodiment.
FIG. 1 is a flow chart of the fault identification of an electric actuator of a gas turbine according to the present invention. The method comprises the following steps: determining a nonlinear model of the electric actuator; adding a non-linear component to an observer; calculating a residual signal; determining a relationship between the residual signal and the fault; introducing feedback proportional to the residual; ensuring that the observer is in a sliding mode; carrying out fault estimation; the nonlinear model of the gas turbine electric actuator is as follows:
Figure BDA0002604112440000061
wherein x is a state vector of the electric actuator; y is a vector of state variables measured by the sensors;
u is a control signal; f is the fault vector; a is a system dynamics matrix; b is a gain vector of the control signal;
c is a vector that determines the nonlinear part of the system; d is an output matrix connecting the state vector and the measurement vector;
e is the fault matrix for the fault location.
The vectors and matrices in the above formula are:
Figure BDA0002604112440000062
Figure BDA0002604112440000063
Figure BDA0002604112440000071
Figure BDA0002604112440000072
in the formula, theta b Is the angle, rad, of the reducer output shaft;
Figure BDA0002604112440000073
Is the rotating speed of the output shaft of the reducer, r/s; theta.theta. t Is the angle of the motor rotor, rad;
Figure BDA0002604112440000074
is the rotational speed of the motor rotor, r/s; i is the current, A; k is the armature inductance, H; i is a reduction ratio; l r Is the back EMF coefficient, Vs/rad; l n Is the viscous friction coefficient of the reducer, Nms/rad; l h Is the viscous friction coefficient of the motor, Nms/rad; l v Is the torque coefficient, Nm/A; k is a radical of bg Is the dry coefficient of friction, Nm, of the retarder; k is a radical of tg Is the dry coefficient of friction, Nm, of the motor; sign is a sign function; j is the moment of inertia of the motor shaft, kg.m 2 (ii) a R is stator resistance, Ω; m is the actuator output shaft torque, Nm; w is the stiffness coefficient of the mechanical transmission, N/m.
The observer is as follows:
Figure BDA0002604112440000075
in the formula (I), the compound is shown in the specification,
Figure BDA0002604112440000076
is the state vector of the observer;
Figure BDA0002604112440000077
is the output signal of the observer;
Figure BDA0002604112440000078
is the dynamics matrix of the observer;
Figure BDA0002604112440000079
is a control signal;
Figure BDA00026041124400000710
is a vector connecting the state vector and the output signal;
Figure BDA00026041124400000711
is a vector containing the nonlinear part of the system in the observer; q is a matrix using state variables in the observer; h (r) is a feedback vector; r is a residual signal.
In the case of no fault, the following conditions must be met:
Figure BDA0002604112440000081
in the formula (I), the compound is shown in the specification,
Figure BDA0002604112440000082
is a matrix connecting the state vectors of the actuator and the observer; ε is the vector that provides the linkage for the state vectors of the actuator and observer.
The residual error r representing whether the electric actuator has a fault is as follows:
Figure BDA0002604112440000083
determining a relationship between residual error and fault, order
Figure BDA0002604112440000084
The following can be obtained:
Figure BDA0002604112440000085
introducing a feedback proportional to the residual error for fault estimation:
Figure BDA0002604112440000086
in the formula, a 1 Is a vector
Figure BDA0002604112440000087
The corresponding element of (1); j is a function of m Is a vector
Figure BDA0002604112440000088
The mth element of (1); f. of n Is the corresponding fault value; c. C m Is a vector
Figure BDA0002604112440000089
The corresponding element of (1); h is m (r) is the corresponding element of the feedback vector h (r).
The corresponding elements of the feedback vector are:
Figure BDA00026041124400000810
in the formula o m Is a positive coefficient. a is s Is a vector
Figure BDA00026041124400000811
The corresponding element of (1);
for the sliding mode, let
Figure BDA00026041124400000812
The following can be obtained:
Figure BDA00026041124400000813
in the formula (I), the compound is shown in the specification,
Figure BDA0002604112440000091
and
Figure BDA0002604112440000092
are the first and second derivatives of the residual signal.
The following conditions are satisfied when the above formula is satisfied:
Figure BDA0002604112440000093
Figure BDA0002604112440000094
in the formula, b nmax Is b n Maximum value of (d); c. C mmax Is c m Is measured.
The fault estimation is carried out by calculating a corresponding fault value f n Carrying out the following steps:
Figure BDA0002604112440000095
in the formula, h eq Is the signal h m Average value of sign (T). The fault value f n The fault causes, the fault positions and the fault time factors.
Fig. 2 is a diagram illustrating the effect of fault recognition of the electric actuator of the gas turbine according to the present invention. As shown in fig. 2, the electric actuator fault is caused by oxidation corrosion of the speed reducer, and the fault is detected and estimated by observing the change of the dry friction coefficient; the method of the invention can effectively detect and estimate the fault value.
The present invention is not limited to the above embodiments, and any changes or substitutions that can be easily made by those skilled in the art within the technical scope of the present invention are also within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (7)

1. A method of identifying a fault in a gas turbine electric actuator, comprising: determining a nonlinear model of the electric actuator; adding a non-linear component to an observer; calculating a residual signal; determining a relationship between the residual signal and the fault; introducing feedback proportional to the residual; ensuring that the observer is in a sliding mode and performing fault estimation; the nonlinear model of the gas turbine electric actuator is characterized in that:
Figure FDA0002604112430000011
wherein x is a state vector of the electric actuator; y is a vector of state variables measured by the sensors; u is a control signal; f is the fault vector; a is a system dynamics matrix; b is a gain vector of the control signal; c is a vector that determines the nonlinear part of the system; d is an output matrix connecting the state vector and the measurement vector; e is the fault matrix for the fault location;
The vectors and matrices in the above formula are:
Figure FDA0002604112430000012
Figure FDA0002604112430000013
Figure FDA0002604112430000021
Figure FDA0002604112430000022
in the formula, theta b Is the angle, rad, of the reducer output shaft;
Figure FDA0002604112430000023
is the rotating speed of the output shaft of the reducer, r/s; theta t Is the angle of the motor rotor, rad;
Figure FDA0002604112430000024
is the rotational speed of the motor rotor, r/s; i is the current, A; k is the armature inductance, H; i is a reduction ratio; l r Is the back EMF coefficient, Vs/rad; l n Is the viscous friction coefficient of the reducer, Nms/rad; l h Is the viscous friction coefficient of the motor, Nms/rad; l v Is the torque coefficient, Nm/A；k bg Is the dry coefficient of friction, Nm, of the retarder; k is a radical of tg Is the dry coefficient of friction, Nm, of the motor; sign is a sign function; j is the moment of inertia of the motor shaft, kg.m 2 (ii) a R is stator resistance, Ω; m is the actuator output shaft torque, Nm; w is the stiffness coefficient of the mechanical transmission, N/m.
2. The method for identifying a fault in an electric actuator of a gas turbine according to claim 1, wherein the observer is:
Figure FDA0002604112430000025
in the formula (I), the compound is shown in the specification,
Figure FDA0002604112430000026
is the state vector of the observer;
Figure FDA0002604112430000027
is the output signal of the observer;
Figure FDA0002604112430000028
is the dynamics matrix of the observer;
Figure FDA0002604112430000029
is a control signal;
Figure FDA00026041124300000210
is a vector connecting the state vector and the output signal;
Figure FDA00026041124300000211
is a vector containing the nonlinear part of the system in the observer; q is a matrix using state variables in the observer; h (r) is a feedback vector; r is a residual signal;
In the case of no fault, the following conditions must be met:
Figure FDA0002604112430000031
in the formula (I), the compound is shown in the specification,
Figure FDA0002604112430000032
is a matrix connecting the state vectors of the actuator and the observer; ε is the vector that provides the linkage for the state vectors of the actuator and observer.
3. The method of claim 1, wherein the residual error signal is calculated, and a residual error r indicating whether a fault exists in the electric actuator is:
Figure FDA0002604112430000033
4. the method of claim 1, wherein the determining the relationship between the residual error and the fault comprises determining a relationship between the residual error and the fault, and wherein the determining the residual error and the fault comprises
Figure FDA0002604112430000034
The following can be obtained:
Figure FDA0002604112430000035
introducing a feedback proportional to the residual error for fault estimation:
Figure FDA0002604112430000036
in the formula, a 1 Is a vector
Figure FDA0002604112430000037
Pair ofA corresponding element; j is a function of m Is a vector
Figure FDA0002604112430000038
The mth element of (1); f. of n Is the corresponding fault value; c. C m Is a vector
Figure FDA0002604112430000039
The corresponding element of (1); h is m (r) is the corresponding element of the feedback vector h (r).
5. The method of identifying a fault in an electric actuator of a gas turbine engine of claim 4, wherein the corresponding elements of the feedback vector are:
Figure FDA00026041124300000310
in the formula o m Is a positive coefficient, a s Is a vector
Figure FDA00026041124300000311
The corresponding elements of (1).
6. The method of identifying a fault in an electric actuator of a gas turbine according to claim 1, wherein the observer is in a sliding mode, and for the sliding mode, the observer is caused to operate in a sliding mode
Figure FDA0002604112430000041
The following can be obtained:
Figure FDA0002604112430000042
in the formula (I), the compound is shown in the specification,
Figure FDA0002604112430000043
and
Figure FDA0002604112430000044
are the first and second derivatives of the residual signal;
the following conditions are satisfied when the above formula is satisfied:
Figure FDA0002604112430000045
Figure FDA0002604112430000046
in the formula, b nmax Is b n Maximum value of (d); c. C mmax Is c m Is measured.
7. Method for fault identification of an electric actuator of a gas turbine according to claim 1, characterized in that said fault estimation is performed by calculating a corresponding fault value f n Carrying out the following steps:
Figure FDA0002604112430000047
in the formula, h eq Is the signal h m Average value of sign (T); the fault value f n The fault causes, the fault positions and the fault time factors.
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