CN110286594B - Self-adaptive dynamic terminal sliding mode control method for active power filter - Google Patents
Self-adaptive dynamic terminal sliding mode control method for active power filter Download PDFInfo
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Abstract
The invention discloses a self-adaptive dynamic terminal sliding mode control method of an active power filter, which comprises the following steps of: s1, establishing a mathematical model of the single-phase active power filter, defining a state variable i as x, and obtaining a second derivative of xThe expression of (1); s2, defining a tracking error and a first derivative thereof, defining a dynamic terminal sliding mode surface to obtain an equivalent control item, then defining a switching control item, and adding the equivalent control item and the switching control item to obtain a dynamic terminal sliding mode controller; and S3, approximating the equivalent control items by using a double-hidden-layer recurrent neural network. The self-adaptive dynamic terminal sliding mode control method of the active power filter can quickly realize no-static-error tracking and achieve lower grid current distortion rate.
Description
Technical Field
The invention relates to a self-adaptive dynamic terminal sliding mode control method of an active power filter, and belongs to the technical field of intelligent control.
Background
Harmonic current suppression technologies become a research hotspot in recent years, and currently, the main harmonic suppression technologies include passive filters and active filters; the passive filter is generally composed of an inductor and a capacitor, is suitable for filtering low-order harmonic waves, and can only filter harmonic waves of specific harmonics, but the passive filter is widely applied to the industrial field due to simple structure and low manufacturing cost, but the compensation precision of the passive filter is not high, and the passive filter can be finally replaced by an active power filter. The active power filter is a novel harmonic compensation device, is an active compensation device, can compensate harmonic waves and can perform reactive compensation, is less affected by the environment, has a wider compensation range on harmonic currents, and is an optimal harmonic suppression device.
The key technology of the active power filter is the design of the controller, and the better controller can better play the compensation performance of the active power filter and reduce the tracking error. The traditional control method is often not high in control accuracy, so that the performance of the active power filter cannot be fully exerted, and in addition, the performance of the active power filter cannot be fully exerted. Existing controllers have high grid current distortion rates.
Disclosure of Invention
The invention aims to provide an active power filter adaptive dynamic terminal sliding mode control method which can quickly realize no-static-error tracking and achieve a lower grid current distortion rate aiming at the defects of the prior art.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
an active power filter self-adaptive dynamic terminal sliding mode control method comprises the following steps:
s1, establishing a mathematical model of the single-phase active power filter, defining a state variable i as x, and obtaining a second derivative of xThe expression of (1);
s2, defining a tracking error and a first derivative thereof, defining a dynamic terminal sliding mode surface to obtain an equivalent control item, then defining a switching control item, and adding the equivalent control item and the switching control item to obtain a terminal sliding mode controller;
and S3, approximating the equivalent control items by using a double-hidden-layer recurrent neural network.
In S1, the mathematical model of the single-phase active power filter is specifically:
where i is the state variable, here denoted the compensating harmonic current, L is the total inductance of the line on the AC side, R is the total resistance of the line on the AC side, UdcIs a DC side voltage, UsIs the grid voltage, H is a defined switching function, for convenience, x-i, if the controller is defined as u ═ H, then equation (1) can be abbreviated as:
where d (t) is the system extra perturbation considered and d (t) is bounded.
In S2, the specific steps are:
s21, defining the tracking error as e ═ x-r, the first derivative of the tracking error asThe second derivative of the tracking error isThen the error vector isWherein r is a reference current signal;
s22, defining a terminal sliding mode surface asc is a tunable coefficient to ensure the stability of the system Herwitz, where P (t) is a terminal function with respect to time t and
the dynamic terminal sliding mode surface is defined as:
wherein λ is a strictly normal number;
the first derivative of the sliding mode surface of the dynamic terminal is as follows:
to achieve global robustness, take e (0) to p (0),in order to realize convergence at a specified time T, when T ≧ T, p (T) 0 is satisfied,we can define the terminal function as:
where T is a self-defined terminal time, e (0),Respectively representing the tracking error and the initial values of its first and second derivatives at t ═ 0s, a00、a01、a02、a10、a11、a12、a20、 a21、a22An available parameter for satisfying the above-mentioned assumption;
S24, taking external interference into consideration, using switching control itemK w0 is any arbitrary constant that ensures the Lyapunov function to be semi-positiveParameter-adjusting and finally-designed dynamic terminal sliding mode controllerThe following steps are changed:
whereinKfAnd < 0 is any adjustable coefficient for ensuring that the Lyapunov function is semi-positive.
Defining the Lyapunov function:
the first derivative of the formula (9) is obtained, and the first derivative of the sliding mode surface of the dynamic terminal in the formula (4) and the control law in the formula (8) are substituted into the first derivative of the Lyapunov function to obtain:
Considering the terminal sliding-mode surface as s ═ C (e (t) -p (t)), where C ═ C1, we define η (t) ═ e (t) -p (t), where e (t) is the error vector,
S03 specifically includes the following steps:
s31, defining the structure of the double hidden layer recurrent neural network as follows: an input layer, a first hidden layer, a second hidden layer and an output layer, and the result of the output layer is fed back to the input layer,
output theta of ith node of input layeriCan be expressed as a number of times,
θi=xi·Wri·exY,i=1,2,...,m (12)
wherein xiIs the ith input of the double hidden layer recurrent neural network, exY is the output value of the neural network at the last moment, WriThe feedback weight vector is defined as W for the feedback weight of the ith input layer noder=[Wr1 Wr2…Wri];
The jth node of the first hidden layer outputs a result phi1jIn order to realize the purpose,
wherein the first hidden layer output vector is phi1=[φ11 φ12…φ1j]And phi is1jRepresenting the output of the jth node of the first hidden layer, the center vector of the Gaussian function of the first hidden layer is C1=[c11,c12,…,c1n]T∈Rn×1The vector of the base width of the Gaussian function is B1=[b11,b12,…,b1n]T∈Rn×1And c is and c1nIn the nth node being the first hidden layerCardiac vector, and b1nIs the nth node center vector, R, of the first hidden layern×1A vector representing n rows and 1 columns in the real number domain;
the kth node of the second hidden layer outputs a result phi2kIn order to realize the purpose,
wherein the second hidden layer output vector is phi2=[φ21 φ22…φ2k]And phi is2kRepresenting the output of the kth node of the second hidden layer, the central vector of the Gaussian function of the second hidden layer is C2=[c21 c22...c2l]T∈Rl×1The vector of the base width of the Gaussian function is B2=[b21 b22...b2l]T∈Rl×1And c is and c2lIs the l-th node-center vector of the second hidden layer, b2lIs the l-th node center vector, R, of the second hidden layerl×1A vector representing l rows and 1 columns in the real number domain;
combining the analysis, the output result of the double hidden layer recurrent neural network is as follows:
Y=WTΦ2=W1φ21+W2φ22+...+Wlφ2l (15)
wherein W ═ W1 W2…Wl]Is the output weight vector, W, of the double hidden layer recurrent neural networklRepresenting a weight vector between the l-th node of the second hidden layer and the output value;
s32, replacing the equivalent control in the formula (6) with the output of the double hidden layer recurrent neural networkMaking an item, i.e.Then the self-adaptive dynamic terminal sliding mode controller based on the double hidden layer recurrent neural network becomes:
s33, the approximation error of the double hidden layer recurrent neural network is defined as:
wherein the superscript denotes an optimal parameter of the corresponding variable, the superscript ^ denotes an estimated value of the corresponding parameter, the superscript ^ denotes an estimated error of the corresponding parameter, and O denoteshFor the higher order terms of the taylor expansion,
Defining a new lyapunov function as:
the first derivative of the Lyapunov function is obtained:
wherein eta1,η2,η3,η4,η5,η6Is an adjustable normal number of the input signals,
in order to stabilize the system, the ideal control law in the formula (8) is added and subtracted to the first derivative of the Lyapunov function in the formula (20) at the same time, and the approximation error in the formula (17) is substituted into the formula (20) to obtain the ideal control law,
the following adaptation law is selected,
whereinRespectively the first derivative, eta, of the approximation error of the parameters of the weight, the feedback gain, the center of the first hidden layer, the base width of the first hidden layer, the center of the second hidden layer and the base width of the second hidden layer of the double hidden layer recurrent neural network1,η2,η3,η4,η5,η6Is an adjustable normal number of the input signals, output phi representing the second hidden layer2Respectively to the parameters The derivative of (c).
Substituting the adaptation laws (22) - (27) into equation (21) yields,
the method can be obtained by simplifying the formula,
as can be seen from the simplified formula (29), since d (t) andbounded, we defineTherefore, as long as K is guaranteedwRho > D, it can be provedThis shows that the terminal sliding mode controller of the double hidden layer recurrent neural network is stable and feasible.
The invention has the beneficial effects that: the invention discloses a self-adaptive dynamic terminal sliding mode control method of an active power filter, which is proved to be stable and feasible, but the model of the active power filter is complex, and parameters cannot be accurately obtained. And finally, the practicability of the algorithm is verified through MATLAB simulation.
Description of the drawings:
FIG. 1 is a schematic diagram of a sliding mode controller of an adaptive dynamic terminal based on a double hidden layer recurrent neural network according to the method of the present invention;
FIG. 2 is a block diagram of a single phase active power filter of the present invention;
fig. 3 is a structural view of a three-phase parallel power supply type active power filter of the present invention;
FIG. 4 is a diagram of a dual hidden layer recurrent neural network of the present invention;
FIG. 5 is a graph of grid current for the present invention;
FIG. 6 is a graph of harmonic current tracking of the present invention;
FIG. 7 is a tracking error map of the present invention;
fig. 8 is a diagram of compensated grid current distortion rate according to the present invention.
Detailed Description
Fig. 1 is a schematic diagram of an adaptive dynamic terminal sliding mode control method of an active power filter according to the present invention, which is intended to explain: detecting harmonic current from load current as a reference signal r, constructing a dynamic terminal sliding mode surface based on a terminal function, designing a switching control item for ensuring the stability of a system, approximating an equivalent control item by using a double-hidden-layer recurrent neural network, outputting a harmonic compensation signal x after the designed control law passes through an active power filter, enabling the error of the system to tend to zero by using negative feedback, and finally achieving the purpose of tracking the reference harmonic current quickly and without static error.
The invention discloses a self-adaptive dynamic terminal sliding mode control method of a source power filter, which comprises the following steps of:
step one, establishing a mathematical model of the single-phase active power filter. FIG. 2 is a block diagram of a single-phase active power filter, in which UsIs the grid current iLIs the load current isIs the grid current icIs to compensate for the harmonic current flow,is a reference harmonic current, L is the total inductance of the AC side line, R is the total resistance of the AC side line, Qi(i ═ 1,2,3,4) are IGBT power electronic switching devices, UdcIs the dc side voltage.
The following dynamic equation can be established according to the theorem of voltage and current:
wherein U isMN=UdcAnd C is the AC side voltage of the active power filter.
For convenience, the switching function is defined:
substituting the switching function into the dynamic equation and solving the first derivative of the time to obtain:
in order to solve the control law, the first derivative is solved, and then the first derivative is changed into a second-order system, and the mathematical model of the single-phase active power filter is obtained by the following specific steps:
where i is the state variable, here denoted the compensating harmonic current, L is the total inductance of the line on the AC side, R is the total resistance of the line on the AC side, UdcIs a DC side voltage, UsIs the network voltage, H is a defined switching function, defines the state variable i as x, obtains the second derivative of xIs described in (1).
For convenience, definitions are providedIf the controller is defined as u ═ H, then equation (1) can be abbreviated as:
where d (t) is the system extra perturbation considered and d (t) is bounded.
The invention is mainly designed for a single-phase active power filter, but actually, the designed controller is not only suitable for the single-phase active power filter, but also suitable for a three-phase three-wire active power filter mathematical model as shown in fig. 3, and for illustration, similar to the single-phase model, the following three-phase kinetic equations can be established by using the voltage and current theorem:
wherein i ═ i1 i2 i3]TTo compensate for the current vector, i1 i2 i3Respectively correspond to a bcCurrent of three phases, dk=[d1k d2k d3k]TIs a switch state function vector; d1k d2k d3kCorresponding to the switching state functions of the three phases a b c. The switching state function of the nth phase is thus defined asckThe definition of the k-th phase switching function is similar to that of a single phase, and specifically comprises the following steps:
the three-phase kinetic equation is simplified to obtain:
whereinFor three-dimensional column vectors, controller u ═ dk. It can be seen that the difference between equation (2) and the simplified equation for the three-phase dynamics equation is only that one is a one-dimensional scalar and one is a three-dimensional column vector, which is the same as the controller for the single-phase active power filter if the controller is designed for each phase of the three-phase mathematical model. Since the design method is the same, only the single-phase model will be explained below.
And step two, defining the tracking error and the first derivative thereof, defining a dynamic terminal sliding mode surface to obtain an equivalent control item, then defining a switching control item, and adding the equivalent control item and the switching control item to obtain the terminal sliding mode controller. The method comprises the following specific steps:
s21, defining the tracking error as e ═ x-r, the first derivative of the tracking error asThe second derivative of the tracking error isThen the error vector isWherein r is a reference current signal;
s22, defining a terminal sliding mode surface asc is a tunable coefficient to ensure the stability of the system Herwitz, where P (t) is a terminal function with respect to time t and
the dynamic terminal sliding mode surface is defined as:
wherein λ is a strictly normal number;
the first derivative of the sliding mode surface of the dynamic terminal is as follows:
to achieve global robustness, take e (0) to p (0),in order to realize convergence at a specified time T, when T ≧ T, p (T) 0 is satisfied,we can define the terminal function as:
where T is a self-defined terminal time, e (0),Respectively representing the tracking error and the initial values of its first and second derivatives at t ═ 0s, a00、a01、a02、a10、a11、a12、a20、 a21、a22An available parameter for satisfying the above-mentioned assumption;
s23, neglecting the influence of unknown disturbance of the system, and makingAvailable equivalent control terms:
S24, because the real system has unknown disturbance, under the condition of considering the unknown disturbance, in order to ensure the system stability, the switching control item is needed to be usedTo eliminate the influence of disturbances, KwMore than 0 is any adjustable parameter for ensuring the Lyapunov function to be semi-positive, and the finally designed dynamic terminal sliding mode controllerThe following steps are changed:
whereinKfAnd < 0 is any adjustable coefficient for ensuring that the Lyapunov function is semi-positive.
Defining the Lyapunov function:
the first derivative of the formula (9) is obtained, and the first derivative of the sliding mode surface of the dynamic terminal in the formula (4) and the control law in the formula (8) are substituted into the first derivative of the Lyapunov function to obtain:
due to d (t) andbounded, defineTherefore, as long as K is guaranteedwRho > D, it can be provedThis shows that the dynamic terminal sliding mode method designed by the invention is stable. On the other hand due toThis means the Lyapunov functionWill gradually decrease, finally V1(t) → 0, which corresponds to σ (t) → 0.
Considering the terminal sliding-mode surface as s ═ C (e (t) -p (t)), where C ═ C1, we define η (t) ═ e (t) -p (t), where e (t) is the error vector,
Step three, because the dynamic terminal sliding mode control law designed by the method needs to be based on an accurate mathematical model, but is difficult to realize in practice, in order to simplify the design of the dynamic terminal control law, the equivalent control item is approximated by using a double-hidden-layer recurrent neural network, and the method specifically comprises the following steps:
s31, defining the structure of the double hidden layer recurrent neural network as follows: an input layer, a first hidden layer, a second hidden layer and an output layer, and the result of the output layer is fed back to the input layer,
output theta of ith node of input layeriCan be expressed as a number of times,
θi=xi·Wri·exY,i=1,2,...,m (12)
wherein xiIs the ith input of the double hidden layer recurrent neural network, exY is the output value of the neural network at the last moment, WriFor the feedback weight of the ith input layer node, the feedback weight vector is defined as Wr ═ Wr1 Wr2…Wri];
The jth node of the first hidden layer outputs a result phi1jIn order to realize the purpose,
wherein the first hidden layer output vector is phi1=[φ11 φ12...φ1j]And phi is1jRepresenting the output of the jth node of the first hidden layer, the Gaussian of the first hidden layerThe central vector of the function is C1=[c11,c12,…,c1n]T∈Rn×1The vector of the base width of the Gaussian function is B1=[b11,b12,…,b1n]T∈Rn×1And c is and c1nIs the nth node center vector of the first hidden layer, and b1nIs the nth node center vector, R, of the first hidden layern×1A vector representing n rows and 1 columns in the real number domain;
the kth node of the second hidden layer outputs a result phi2kIn order to realize the purpose,
wherein the second hidden layer output vector is phi2=[φ21 φ22…φ2k]And phi is2kRepresenting the output of the kth node of the second hidden layer, the central vector of the Gaussian function of the second hidden layer is C2=[c21 c22...c2l]T∈Rl×1The vector of the base width of the Gaussian function is B2=[b21 b22...b2l]T∈Rl×1And c is and c2lIs the l-th node-center vector of the second hidden layer, b2lIs the l-th node center vector, R, of the second hidden layerl×1A vector representing l rows and 1 columns in the real number domain;
combining the analysis, the output result of the double hidden layer recurrent neural network is as follows:
Y=WTΦ2=W1φ21+W2φ22+...+Wlφ2l (15)
wherein W ═ W1 W2…Wl]Is the output weight vector, W, of the double hidden layer recurrent neural networklRepresenting a weight vector between the l-th node of the second hidden layer and the output value;
s32, replacing the equivalent control item in the formula (6) with the output of the double hidden layer recurrent neural network, namelyThen the self-adaptive dynamic terminal sliding mode controller based on the double hidden layer recurrent neural network becomes:
s33, the approximation error of the double hidden layer recurrent neural network is defined as:
wherein the upper mark indicates the optimal parameter of the corresponding variable, and the upper mark A indicates the correspondenceEstimated value of a parameter, superscript-representing the estimation error of the corresponding parameter, OhFor the higher order terms of the taylor expansion,
Defining a new lyapunov function as:
the first derivative of the Lyapunov function is obtained:
wherein eta1,η2,η3,η4,η5,η6Is an adjustable normal number of the input signals,
in order to stabilize the system, the ideal control law in the formula (8) is added and subtracted to the first derivative of the Lyapunov function in the formula (20) at the same time, and the approximation error in the formula (17) is substituted into the formula (20) to obtain the ideal control law,
whereinRespectively the first derivative, eta, of the approximation error of the parameters of the weight, the feedback gain, the center of the first hidden layer, the base width of the first hidden layer, the center of the second hidden layer and the base width of the second hidden layer of the double hidden layer recurrent neural network1,η2,η3,η4,η5,η6Is an adjustable normal number of the input signals, output phi representing the second hidden layer2Respectively to the parameters The derivative of (c). Can finally proveThis shows that the terminal sliding mode controller of the double hidden layer recurrent neural network is stable and feasible.
And then, simulating the controller on the single-phase active power filter model by using MATLAB, wherein simulation parameters are selected as follows:
the voltage of the power grid is Us24V, f 50 Hz; resistance R of nonlinear steady-state load1=5Ω,R215 omega, a capacitance C of 1000uF, and a resistance of the dynamic nonlinear load R1=15Ω,R215 Ω, and 1000 uF. The main circuit parameters of the active power filter comprise that the line inductance is 0.018H, and the resistance is 1 omega; since the dc side voltage is controlled by a conventional PI control method, the dc side voltage is assumed to be a constant value of 50v, and the experimental result graphs are shown in fig. 5, 6, 7, and 8.
In the simulation process, 0.05s is inserted into the active power filter, namely the active power filter starts to work to perform harmonic current compensation at the moment, and a dynamic nonlinear load is connected in 0.3 s. As can be seen from fig. 5, the grid current distortion rate is severe at the beginning, and the quality and safety of the grid may be compromised if no harmonic compensation is performed. When the active power filter is connected to the power grid within 0.05s, the power grid current can be changed into a sine wave within a short time. Even if the load changes, the grid current can change into a sinusoidal waveform in a short time. Fig. 6 is a harmonic current tracking curve of the present invention, after 0.05s, the harmonic compensation current can track the harmonic reference current in a short time, and after 0.3s nonlinear load change, the harmonic compensation current can also track quickly, which illustrates that the dynamic performance of the present invention is better. Fig. 7 is a tracking error map of the present invention, and it can be seen that the range of variation of the tracking error is small. Fig. 8 is a diagram of the distortion rate of the current in the power grid after the active power filter starts to work, and it can be seen that the distortion rate is 3.11% at this time, so as to fully reach 5% of the international standard requirement. The dynamic terminal self-adaptive sliding mode control method based on the double hidden layers of the recurrent neural network has good compensation effect and robustness.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (3)
1. An active power filter self-adaptive dynamic terminal sliding mode control method is characterized by comprising the following steps: the method comprises the following steps:
s1, establishing a mathematical model of the single-phase active power filter, defining a state variable i as x, and obtaining a second derivative of xThe expression of (2) is that the mathematical model of the single-phase active power filter specifically comprises:
where i is the state variable, here denoted the compensating harmonic current, L is the total inductance of the line on the AC side, R is the total resistance of the line on the AC side, UdcIs a DC side voltage, UsIs the grid voltage, H is a defined switching function, for convenience, x-i, if the controller is defined as u ═ H, then equation (1) can be abbreviated as:
where d (t) is the system extra perturbation considered and d (t) is bounded;
s2, defining the tracking error and the first derivative thereof, defining a dynamic terminal sliding mode surface to obtain an equivalent control item, then defining a switching control item, and adding the equivalent control item and the switching control item to obtain the terminal sliding mode controller, which comprises the following specific steps:
s21, defining traceThe error is e ═ x-r, the first derivative of the tracking error isThe second derivative of the tracking error isThen the error vector isWherein r is a reference current signal;
s22, defining a terminal sliding mode surface asc is a tunable coefficient to ensure the stability of the system Herwitz, where P (t) is a terminal function with respect to time t and
the dynamic terminal sliding mode surface is defined as:
wherein λ is a normal number;
the first derivative of the sliding mode surface of the dynamic terminal is as follows:
to achieve global robustness, take e (0) to p (0),in order to realize convergence at a specified time T, when T ≧ T, p (T) 0 is satisfied,defining the terminal function as:
where T is a self-defined terminal time, e (0),Respectively representing the tracking error and the initial values of its first and second derivatives at t ═ 0s, a00、a01、a02、a10、a11、a12、a20、a21、a22An available parameter for satisfying the above-mentioned assumption;
S24, taking external interference into consideration, using switching control itemKwMore than 0 is any adjustable parameter for ensuring the Lyapunov function to be semi-positive, and the finally designed dynamic terminal sliding mode controllerThe following steps are changed:
s3, approximating the equivalent control item by using a double-hidden-layer recurrent neural network, which specifically comprises the following steps:
s31, defining the structure of the double hidden layer recurrent neural network as follows: an input layer, a first hidden layer, a second hidden layer and an output layer, and the result of the output layer is fed back to the input layer,
output theta of ith node of input layeriCan be expressed as a number of times,
θi=xi·Wri·exY,i=1,2,...,m (12)
wherein xiIs the ith input of the double hidden layer recurrent neural network, exY is the output value of the neural network at the last moment, WriThe feedback weight vector is defined as W for the feedback weight of the ith input layer noder=[Wr1 Wr2...Wri];
The jth node of the first hidden layer outputs a result phi1jIn order to realize the purpose,
wherein the first hidden layer output vector is phi1=[φ11 φ12...φ1j]And phi is1jRepresenting the output of the jth node of the first hidden layer, the center vector of the Gaussian function of the first hidden layer is C1=[c11,c12,...,c1n]T∈Rn×1The vector of the base width of the Gaussian function is B1=[b11,b12,…,b1n]T∈Rn×1And c is and c1nIs the nth node center vector of the first hidden layer, and b1nIs the nth node center vector, R, of the first hidden layern×1A vector representing n rows and 1 columns in the real number domain;
the kth node of the second hidden layer outputs a result phi2kIn order to realize the purpose,
wherein the second hidden layer output vector is phi2=[φ21 φ22...φ2k]And phi is2kRepresenting the output of the kth node of the second hidden layer, the central vector of the Gaussian function of the second hidden layer is C2=[c21 c22...c2l]T∈Rl×1The vector of the base width of the Gaussian function is B2=[b21 b22...b2l]T∈Rl×1And c is and c2lIs the l-th node-center vector of the second hidden layer, b2lIs the l-th node center vector, R, of the second hidden layerl×1A vector representing l rows and 1 columns in the real number domain;
combining the analysis, the output result of the double hidden layer recurrent neural network is as follows:
Y=WTΦ2=W1φ21+W2φ22+...+Wlφ2l (15)
wherein W ═ W1 W2...Wl]Is the output weight vector, W, of the double hidden layer recurrent neural networklRepresenting a weight vector between the l-th node of the second hidden layer and the output value;
s32, replacing the equivalent control item in the formula (6) with the output of the double hidden layer recurrent neural network, namelyThen the self-adaptive dynamic terminal sliding mode controller based on the double hidden layer recurrent neural network becomes:
s33, the approximation error of the double hidden layer recurrent neural network is defined as:
wherein the superscript denotes the optimal parameter of the corresponding variable, the superscript Λ denotes the estimated value of the corresponding parameter, the superscript denotes the estimated error of the corresponding parameter, and OhFor the higher order terms of the taylor expansion,
2. The adaptive dynamic terminal sliding-mode control method of the active power filter according to claim 1, characterized in that: defining the Lyapunov function:
solving a first derivative of the formula (9), and substituting the first derivative of the sliding mode surface of the dynamic terminal in the formula (4) and the control law in the formula (8) into the first derivative of the Lyapunov function to obtain:
Considering a terminal sliding mode surface as s ═ C (e (t) -p (t)), where C ═ C1 is an adjustable vector that ensures system stability, we define η (t) ═ e (t) -p (t), where e (t) is an error vector,
3. The adaptive dynamic terminal sliding-mode control method of the active power filter according to claim 1, characterized in that: defining a new lyapunov function as:
the first derivative of the Lyapunov function is obtained:
wherein eta1,η2,η3,η4,η5,η6Is an adjustable normal number of the input signals,
in order to stabilize the system, the ideal control law in the formula (8) is added and subtracted to the first derivative of the Lyapunov function in the formula (20) at the same time, and the approximation error in the formula (17) is substituted into the formula (20) to obtain the ideal control law,
whereinRespectively the first derivative, eta, of the approximation error of the parameters of the weight, the feedback gain, the center of the first hidden layer, the base width of the first hidden layer, the center of the second hidden layer and the base width of the second hidden layer of the double hidden layer recurrent neural network1,η2,η3,η4,η5,η6Is an adjustable normal number of the input signals, output phi representing the second hidden layer2Respectively to the parameters The derivative of (c).
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