Disclosure of Invention
In order to solve the problems, the invention discloses a robust asynchronous control method of a time lag hydroturbine regulating system with pulse perturbation
The specific scheme is as follows:
a robust asynchronous control method for a time lag hydroturbine adjusting system with pulse perturbation comprises the following steps: establishing a mathematical model of a nonlinear time-lag singular hybrid water turbine adjusting system with pulse perturbation; selecting proper front variables and membership functions, and constructing a fuzzy time-lag singular hybrid water turbine adjusting system with pulse perturbation; and establishing an asynchronous state feedback controller to realize robust asynchronous stabilization of the fuzzy time-lag singular hybrid water turbine regulating system with pulse perturbation. By constructing a novel pulse time dependent lyapunov functional; robust stabilization of a fuzzy time-lag singular hybrid turbine adjusting system with pulse perturbation is realized; finally, through a simulation example, the effectiveness of the proposed asynchronous control method is verified.
As a further improvement of the present invention, the method specifically comprises the following steps:
(a) The correlation between the turbine relative head h and the flow q is expressed as:
wherein the water hammer wave reflection time constant and the water inertia time constant are respectively T q and hw A representation; and carrying out Laplace inverse transformation on the hyperbolic tangent function to obtain a time-lag algebraic equation in a time domain:
h(t)=-h(t-T q )+2h w q(t-T q )-2h w q(t), (2)
the turbine model with less variation under steady state conditions can be linearized as:
wherein the relative deviation of the moment is m s (t) the relative deviations of the generator speed and the servo output are denoted by x p (t) and y (t);
then, six transfer coefficients of the water turbine can be obtained through the characteristic curves of the moment and the flow:
while the nonlinear characteristics of synchronous generators are described as:
wherein the rotor angle and the generator damping coefficient are respectivelyReplaced with (t) and χ. T (T) s and mp Respectively representing the inertia time constant and the electromagnetic torque of the generator motor;
in analyzing the dynamic characteristics of the generator system, the influence of the rotational speed variation on the generator is taken into account. Electromagnetic power is generally considered to be equal to electromagnetic torque;
m p (t)=P e (t), (6)
the electromagnetic power is expressed as:
wherein the armature transient internal voltage, the bus infinite voltage and the direct axis transient reactance are respectively E' q 、V s and x′d A representation; x is x q 、x T and xL (r t ) Respectively representing the reactance of the tetrad axis, the short-circuit reactance of the transformer and the reactance of different transmission lines;
driving the turbine guide vane by a servo system, and converting a weak control signal u (t) into a mechanical displacement signal y (t); the dynamics of the hydraulic servo system can be expressed as:
wherein Ty (r t ) Representing a main relay connector response time;
let x be 1 、x 2 、x 3 and x4 Respectively representx p Y and h; meanwhile, it is considered that the malfunction of circuit elements, the ambient noise and the abrupt increase or decrease of water flow may cause a "pulse" phenomenon. Combining (1) - (9) to obtain a toolThe mathematical model of the nonlinear time-lag singular hybrid water turbine adjusting system with pulse perturbation is as follows:
wherein ,
f 1 (x(t),r t )=x 0 x p (t),
f 4 (x(t),r t )=(2h w e qx x p (t)+2h w e qy y(t)+(2h w e qh +1)h(t)),
x(t)=[x 1 (t)x 2 (t)x 3 (t)x 4 (t)] T is a state vector, u (t) is a control input, ω (t) is an external disturbance, z (t) is an estimated output,is a pulse operator, { t k The sequence represents the pulse instants and satisfies 0=t 0 <t 1 <t 2 <···<t k <t k+1 <···;
{r t The markov jump procedure is represented and takes a value in the set s= {1,2, M, pi= [ pi ] rl ]A transfer rate matrix for satisfying general conditions;
(b) Consider x in system (10) 1 ∈[-p,p]Based on the T-S fuzzy method, the linear model is adopted to represent the local dynamics of different state space regions. The local linear models are mixed through a fuzzy membership function, and a time-lag singular hybrid water turbine adjusting system with pulse perturbation can be constructed by utilizing two fuzzy rules of the system (10). Selecting rotor angleAs a membership function of the precursor variables:
rule 1: if x 1 (t) is affiliated toThen
Rule 2: if x 1 (t) is affiliated toThen
To conveniently obtain coefficient matrix A of system (10) i (r t ) (i=1, 2) using Maclaurin series;
wherein
When r is t =r∈S,In the process, considering (12), selecting the first three items of Maclaurin series, and obtaining an overall fuzzy model of the system (10) as follows:
wherein ,
I kil generalized pulse operator I under ith fuzzy rule kl ;
(c) Designing an asynchronous fuzzy state feedback controller;
rule 1: if x 1 (t) is affiliated toThen
u(t)=K 1 (κ t )x(t);
Rule 2: if x 1 (t) is affiliated toThen
u(t)=K 2 (κ t )x(t);
According to the parallel distributed compensation technology and the hidden Markov model mechanism, the overall fuzzy model of the asynchronous fuzzy state feedback controller is obtained as follows:
{κ t is dependent on { r } t Markov jump procedure atTaking a value of the middle value;
P{κ t =κ|r t =r}=q rκ (15)
representing conditional probability, p= [ q ] rκ ]Representing a conditional probability matrix, for each r.epsilon.S, there is(r t ,κ t Pi, P) represents a hidden Markov model, K j (κ t ) The gain of the asynchronous fuzzy state feedback controller under the condition of a fuzzy rule j is obtained;
(d) In order to make the results more generic, a general form of the fuzzy time-lag singular confounding system with impulse perturbation is given below:
fuzzy rule i (i=1, 2,., m)
If lambda is 1 (t) is affiliated toλ 2 (t) belonging to->…λ n (t) belonging to->Then
wherein ,representing fuzzy sets, lambda v (t) (v=1, 2,., n) is a front piece variable;
(e) Based on the T-S fuzzy strategy, the fuzzy time-lag singular confounding system (16) with impulse perturbation is expressed as:
wherein ,
and m is the number of IF-THEN rules,represents a normalized fuzzy weighting function, λ (t) = [ λ ] 1 (t),λ 2 (t),...,λ n (t)],Is->Lambda in (lambda) j Membership function of (t). At the pulse time, < >>Representing a normalized fuzzy weighting function, lambda (t k )=[λ 1 (t k ),λ 2 (t k ),...,λ n (t k )],Represented by lambda v (t k ) At->Membership functions in (a);
(f) The generalized asynchronous fuzzy state feedback controller is expressed as:
fuzzy rule j (j=1, 2,., m.)
If lambda is 1 (t) is affiliated toλ 2 (t) belonging to->…λ n (t) belonging to->Then
(g) Combining (16) - (18), when r t =r∈S, and κt =κ e Θ, resulting in a closed loop fuzzy time-lag singular hybrid system with pulsed perturbation:
wherein ,
(h) Definition:
(A) For each r t =r∈S,κ t =κ∈Θ, pairIs regular, pulse-free, a closed loop fuzzy time-lag singular confounding system (19) with pulse perturbation is said to be non-forced, regular, pulse-free;
(B) If there is a scalar quantityA closed loop fuzzy time-lapse singular hybrid system (19) with non-forced impulse perturbation is considered randomly stable if the following formula holds;
(C) If the closed loop fuzzy time-lapse singular confounding system (19) with non-forced impulse perturbation is regular, non-impulse and randomly stable, then the closed loop fuzzy time-lapse singular confounding system (19) with non-forced impulse perturbation is said to be randomly tolerant.
(i) For a given pulse sequence whereinFirst some auxiliary functions are introduced for +.>
Note thatThere is a function +.>So that
ρ 2 (t)=1-ρ 1 (t);
(j) Given a class of pulse time sequences, for all r t =r∈S,κ t Defining matrix P with =κ∈Θ and g=1, 2 r > 0, Q > 0 and scalar sigma > 0, T q >0,Sigma = min {1, sigma }, designing a lyapunov functional dependent on pulse time, and studying the stability condition of a closed-loop fuzzy time-lag singular hybrid system (19) with pulse perturbation:
wherein ,
wherein phi (t) =sigma ρ1(t) ;
Defining a random procedure { x } t ,r t ,κ t Acts on V (x) t ,r t ,κ t ) Weak infinity small operator on
Note thatHas the following components
Combining (21) - (25), when ω (t) =0, there are
wherein ,
on the other hand, consider V (t k) and relation of (2)
There is a scalar quantitySo that
According to the Deng Jin formula, for t > t s > 0, have
Thus there is
On the other hand, there are
Thus, the first and second substrates are bonded together,
wherein ,
(k) Is available according to the schulp lemma and the lyapunov theorem, when the following conditions are satisfied,
Λ ghrκ <0, (30)
(I+I khl ) T E T P r (I+I khl )≤σE T P l , (32)
wherein ,
the system can meet the random tolerance and has H ∞ Performance index;
(l) Designing an asynchronous fuzzy state feedback controller:
order the
wherein ,
simultaneous command
wherein ,
(m) according to Moore-Penrose inverse method, when the following linear matrix inequality is satisfied
wherein ,
the gain of the asynchronous fuzzy state feedback controller (18) may then be expressed as:
the system satisfies the random tolerance and satisfies H ∞ Performance index.
The method combines with some practical problems, and designs an asynchronous fuzzy state feedback controller aiming at a nonlinear time-lag singular hybrid water turbine adjusting system with pulse perturbation; compared with the prior art, the technical scheme provided by the invention has the beneficial effects that:
1. the modeling fuzzy time-lag singular hybrid water turbine adjusting system with pulse perturbation can simultaneously consider the influence of different reactance on the system due to different line switching in the working process of the water turbine system, the system with different reactance is modeled as a subsystem of a Markov system, and jump among the subsystems is compliant with the Markov chain; meanwhile, the method does not need to approach a time lag algebraic equation, and can resist damage to a water turbine system caused by sudden increase/decrease of water flow, failure of circuit elements and environmental noise; compared with the conventional water turbine regulating system modeling as a general linear system researching robust asynchronous control, the method can more effectively cope with the actual engineering problem;
2. the modal information of the fuzzy time-lag singular hybrid turbine tuning system is not fully accessible due to unavoidable delays, networking mechanisms, measurement errors, etc., which results in asynchronous problems between the controller and the controlled system. According to the invention, an asynchronous fuzzy state feedback controller is designed under a hidden Markov model mechanism, so that the modal asynchronous problem is successfully overcome, and the robust asynchronous control of the time-lag singular hybrid water turbine regulating system is realized;
3. the invention constructs a Lyapunov functional which is dependent on pulse time, and can effectively capture the characteristics and information of a Markov jump mode and the pulse moment; at the same time, the pulse operator value range is promoted to n×n Therefore, the method provided by the invention is more universal.
Detailed Description
The following description of the embodiments of the invention is presented in conjunction with the accompanying drawings to provide a better understanding of the invention to those skilled in the art. It is noted that in the following description, detailed descriptions of known functions and designs will be omitted herein as perhaps obscuring the subject matter of the present invention.
As shown in the figure, the invention provides a robust asynchronous control method for a time lag hydroturbine adjusting system with pulse perturbation, which specifically comprises the following steps:
(a) The correlation between the turbine relative head h and the flow q is expressed as:
wherein the water hammer wave reflection time constant and the water inertia time constant are respectively T q and hw A representation; and carrying out Laplace inverse transformation on the hyperbolic tangent function to obtain a time-lag algebraic equation in a time domain:
h(t)=-h(t-T q )+2h w q(t-T q )-2h w q(t),
the turbine model with less variation under steady state conditions can be linearized as:
wherein the relative deviation of the moment is m s (t) the relative deviations of the generator speed and the servo output are denoted by x p (t) and y (t);
then, six transfer coefficients of the water turbine can be obtained through the characteristic curves of the moment and the flow:
while the nonlinear characteristics of synchronous generators are described as:
wherein rotor angle and generator damping coefficient are respectively usedAnd χ. T (T) s and mp Respectively representing the inertia time constant and the electromagnetic torque of the generator motor;
in analyzing the dynamic characteristics of the generator system, the influence of the rotational speed variation on the generator is taken into account. Electromagnetic power is generally considered equal to electromagnetic torque:
m p (t)=P e (t),
the electromagnetic power is expressed as:
wherein the armature transient internal voltage, the bus infinite voltage and the direct axis transient reactance are respectively E' q 、V s and x′d A representation; x is x q 、x T and xL (r t ) Respectively representing the reactance of the tetrad axis, the short-circuit reactance of the transformer and the reactance of different transmission lines;
driving the turbine guide vane by a servo system, and converting a weak control signal u (t) into a mechanical displacement signal y (t); the dynamics of the hydraulic servo system can be expressed as:
wherein Ty (r t ) Representing a main relay connector response time;
let x be 1 、x 2 、x 3 and x4 Respectively represent x p Y and h; meanwhile, considering that the phenomenon of pulse is possibly caused by fault circuit elements, environmental noise and sudden increase and decrease of water flow, the mathematical model of the nonlinear time-lag singular hybrid water turbine adjusting system with pulse perturbation is obtained as follows:
wherein ,
f 1 (x(t),r t )=x 0 x p (t),
f 4 (x(t),r t )=(2h w e qx x p (t)+2h w e qy y(t)+(2h w e qh +1)h(t)),
x(t)=[x 1 (t)x 2 (t)x 3 (t)x 4 (t)] T is a state vector, u (t) is a control input, ω (t) is an external disturbance, z (t) is an estimated output,is a pulse operator, { t k The sequence represents the pulse instants and satisfies 0=t 0 <t 1 <t 2 <···<t k <t k+1 <···;
{r t The markov jump procedure is represented and takes a value in the set s= {1,2, M, pi= [ pi ] rl ]A transfer rate matrix for satisfying general conditions;
(b) Consider x in a system 1 ∈[-p,p]Based on the T-S fuzzy method, the linear model is adopted to represent the local dynamics of different state space regions. The local linear models are mixed through fuzzy membership functions, and time lag odd abnormal mixing with pulse perturbation can be constructed by utilizing two fuzzy rules of the systemAnd a hybrid water turbine regulating system. Rotor angle (t) is selected as a membership function of the front piece variable:
rule 1: if x 1 (t) is affiliated toThen
Rule 2: if x 1 (t) is affiliated toThen
To conveniently obtain coefficient matrix A of system i (r t ) (i=1, 2) using Maclaurin series;
wherein
When r is t =r∈S,When the system is used, the first three items of Maclaurin series are selected, and the overall fuzzy model of the system is obtained as follows:
wherein , I kil generalized pulse operator I under ith fuzzy rule kl ;/>
(c) Designing an asynchronous fuzzy state feedback controller;
rule 1: if x 1 (t) is affiliated toThen
u(t)=K 1 (κ t )x(t);
Rule 2: if x 1 (t) is affiliated toThen
u(t)=K 2 (κ t )x(t);
According to the parallel distributed compensation technology and the hidden Markov model mechanism, the overall fuzzy model of the asynchronous fuzzy state feedback controller is obtained as follows:
{κ t is dependent on { r } t Markov jump procedure atTaking a value of the middle value;
P{κ t =κ|r t =r}=q rκ
representing conditional probability, p= [ q ] rκ ]Representing a conditional probability matrix, for each r.epsilon.S, there is(r t ,κ t Pi, P) represents a hidden Markov model, K j (κ t ) The gain of the asynchronous fuzzy state feedback controller under the condition of a fuzzy rule j is obtained;
(d) In order to make the results more generic, a general form of the fuzzy time-lag singular confounding system with impulse perturbation is given below:
fuzzy rule i (i=1, 2,., m)
If lambda is 1 (t) is affiliated toλ 2 (t) belonging to->…λ n (t) belonging to->Then
wherein ,representing fuzzy sets, lambda v (t) (v=1, 2,., n) is a front piece variable;
(e) Based on the T-S fuzzy strategy, the fuzzy time-lag singular confounding system (16) with impulse perturbation is expressed as:
wherein ,
and m is the number of IF-THEN rules,represents a normalized fuzzy weighting function, λ (t) = [ λ ] 1 (t),λ 2 (t),...,λ n (t)],Is->Lambda in (lambda) j Membership function of (t). At the pulse time, < >>Representing a normalized fuzzy weighting function, lambda (t k )=[λ 1 (t k ),λ 2 (t k ),...,λ n (t k )],Represented by lambda v (t k ) At->Membership functions in (a);
(f) The generalized asynchronous fuzzy state feedback controller is expressed as:
fuzzy rule j (j=1, 2,., m.)
If lambda is 1 (t) is affiliated toλ 2 (t) belonging to->…λ n (t) belonging to->Then
(g) When r is t =r∈S, and κt =κ e Θ, resulting in a closed loop fuzzy time-lag singular hybrid system with pulsed perturbation:
wherein ,
(h) Definition:
(A) For each r t =r∈S,κ t =κ∈Θ, pairThe closed loop fuzzy time lag singular hybrid system with pulse perturbation is regular and pulse-free;
(B) If there is a scalar quantityA closed loop fuzzy time-lag singular hybrid system with non-forced impulse perturbation is considered to be randomly stable if the following formula holds; />
(C) If the closed loop fuzzy time-lapse singular confounding system with non-forced impulse perturbation is regular, pulse-free and randomly stable, then the closed loop fuzzy time-lapse singular confounding system with non-forced impulse perturbation is said to be randomly tolerant.
In this embodiment, the parameters shown in table 1 were selected:
table 1: system parameters and design parameters
| x 0 |
T s |
e x |
e y |
| 1 |
9 |
0 |
1 |
| e h |
e qx |
e qy |
e qh |
| 1.5 |
0 |
1 |
0.5 |
| χ |
E′ q |
V s |
h w |
| 2 |
1.35 |
1 |
0.5 |
| T y1 |
T y2 |
T y3 |
x′ dΣ1 |
| 0.1 |
0.2 |
0.5 |
1.15 |
| x′ dΣ2 |
x′ dΣ3 |
x qΣ1 |
x qΣ2 |
| 1.25 |
1 |
1.474 |
1.600 |
| x qΣ3 |
p |
σ |
T q |
| 1 |
4 |
1.2 |
0.2 |
The technical means disclosed by the scheme of the invention is not limited to the technical means disclosed by the embodiment, and also comprises the technical scheme formed by any combination of the technical features. It should be noted that modifications and adaptations to the invention may occur to one skilled in the art without departing from the principles of the present invention and are intended to be within the scope of the present invention.