CN117081092A - Static var generator controller based on multi-mode expansion state observation - Google Patents
Static var generator controller based on multi-mode expansion state observation Download PDFInfo
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- H—ELECTRICITY
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Abstract
The invention provides a static var generator controller based on multi-mode expanded state observation, which comprises the following components: the system comprises a coordinate transformation unit, an active current controller, a direct current voltage controller, a reactive current controller and an SVPWM unit; the active current controller comprises a first multi-mode expansion state observation unit, a first monitor unit and a first controller unit; the direct-current voltage controller comprises a second multi-mode expansion state observation unit, a second monitor unit and a second controller unit; the reactive current controller comprises a third multi-mode extended state observation unit, a third monitor unit and a third controller unit. The invention designs a group of extended state observers based on nominal control gain, carries out on-line evaluation on the estimation performance of the extended state observers based on state estimation errors, selects the extended state observer matched with the optimal model, and realizes the accurate estimation disturbance and model parameter matching of the static var generator when reactive compensation is carried out.
Description
Technical Field
The invention relates to the technical field of direct current control of a static var generator, in particular to a static var generator controller based on multi-mode extended state observation.
Background
The basic principle of a Static Var Generator (SVG) is that reactive power in a power grid is precisely controlled and regulated through a power electronic device, so that the phase difference of voltage and current is kept in a proper range, and the purpose of reactive power compensation is achieved. The control system of the SVG is a core part of the SVG and is mainly responsible for controlling and regulating power electronic devices, so that the accurate control of reactive power in a power grid is realized.
The existing control method of the static var generator can be divided into the following two main types: one is based on voltage control and the other is based on current control. A Static Var Generator (SVG) based on voltage control, the basic principle of which is to make the reactive power output by the SVG proportional to the grid voltage by changing the phase and amplitude of the SVG output current. The method has the advantages of higher control response speed, higher control precision and smaller harmonic response to system current, but has the disadvantages of higher control voltage, larger influence by system voltage fluctuation and weaker response to unbalanced voltage of the power grid. The SVG control method based on current control is based on the basic principle that the reactive power output by SVG is in proportion to the current error by controlling the phase and amplitude of the current output by SVG. The method has the advantages of strong response capability to unbalanced voltage of the power grid, low control voltage requirement and small influence of system voltage fluctuation, and has the defects of low control response speed, low control precision and strong response to system current harmonic waves.
The common control algorithm comprises PI control, fuzzy control, neural network control and the like, wherein the PI control algorithm is the most common control algorithm and has the advantages of simplicity in implementation, good regulation performance and the like; compared with the traditional accurate control method, the fuzzy control method has the characteristics of being capable of adapting to different power systems, having good adaptability and robustness, being capable of processing uncertainty and nonlinearity problems in the system and improving the expansion performance and stability of the system; compared with the traditional PI control and fuzzy control, the static var generator controlled by the neural network has the advantages of strong self-adaptability and good robustness, and can process a plurality of input and output variables simultaneously, so that the performance of the static var generator can be comprehensively controlled and optimized. In addition, there are also hybrid control methods, such as a method based on voltage-current control, a method based on voltage-power control, etc., which can combine the advantages of various control algorithms to achieve better control effects. Different SVG control methods have advantages and disadvantages, and are selected and applied according to the characteristics and requirements of the power system.
However, in the control study of the static var generator, the prior art has the following disadvantages in terms of controller design and control effect: first, the controller design of existing static var generators relies on some of the exact model parameters, which may vary in the actual system, making it difficult to obtain their exact values. Secondly, most of the existing static var generator controllers adopt a passive anti-interference method, have certain hysteresis, and cannot realize active anti-interference.
Disclosure of Invention
In view of the shortcomings of the prior art, the invention provides a static var generator controller based on multi-mode extended state observation. The invention designs a group of extended state observers based on nominal control gain, carries out on-line evaluation on the estimated performance of the extended state observers based on state estimation errors, establishes an evaluation selection mechanism, selects the extended state observer matched with the optimal model, and realizes accurate estimation disturbance and model parameter matching when the static var generator carries out reactive compensation.
The invention adopts the following technical means:
a static var generator controller based on multi-modal extended state observations, comprising: the system comprises a coordinate transformation unit, an active current controller, a direct current voltage controller, a reactive current controller and an SVPWM unit;
the active current controller comprises a first multi-mode expansion state observation unit, a first monitor unit and a first controller unit; the direct-current voltage controller comprises a second multi-mode expansion state observation unit, a second monitor unit and a second controller unit; the reactive current controller comprises a third multimode expanded state observation unit, a third monitor unit and a third controller unit;
the coordinate transformation unit consists of a 3s/2r coordinate transformation unit and a 2r/2s coordinate transformation unit, the 3s/2r coordinate transformation unit is used for realizing transformation between a three-phase static coordinate system A-B-C and a two-phase rotating coordinate system d-q, and the input of the 3s/2r coordinate transformation unit is current i in a power grid a 、i b And i c Output as a current signal i which is required to be transformed into a two-phase rotating coordinate system d And i q Current signal i d Is connected with the input ends of the first multi-mode expanded state observation unit and the second monitor unit, i q Is connected with a third multi-mode expanded state observation unit and a third monitor unit 3; the 2r/2s coordinate transformation unit is used for transforming the two-phase rotating coordinate system d-q and the two-phase static coordinate system alpha-beta, and the input of the 2r/2s coordinate transformation unit is u output by the second controller unit d And u output from the third controller unit q ；
The output end of the first multi-mode expansion state observation unit is connected with the first monitor unit, and the output end of the first monitor unit is connected with the input end of the first controller unit;
the output end of the second multimode extended state observation unit is connected with a second monitor unit, the output end of the second monitor unit is connected with the input end of the second controller unit, and u is output by the second controller unit q 2r/2s coordinate transformation is carried out and then the SVPWM unit is connected with the input end of the SVPWM unit;
the output end of the third multimode expanded state observation unit and the third monitor unitThe output end of the third monitor unit is connected with the third controller unit, and u is output by the third controller unit q 2r/2s conversion is carried out and then the converted signal is connected with the input end of the SVPWM unit;
the SVPWM unit generates a modulation signal to control the state of a switching tube in a main circuit of the static var generator, and the SVPWM unit is a space voltage vector modulation unit.
Compared with the prior art, the invention has the following advantages:
firstly, the static var generator controller design method based on the multimode extended state observer does not need any precisely known model parameter information, only needs the nominal value of known control gain, relaxes the dependence on model parameters, and has universality in controller design.
Secondly, different from the passive disturbance compensation mode of the existing reactive power generator controller, the method can accurately estimate the uncertainty of the system model parameters and the external disturbance, actively estimate and actively compensate the disturbance, and improve the robustness of the system.
Third, the system equation of the active current controller and the direct current voltage controller is a second-order system, and when a control scheme is designed for the system equation, the invention adopts the thought of a back-stepping method, gradually designs the control scheme, and constructs the design process of the controller.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort to a person skilled in the art.
Fig. 1 is a schematic diagram of a static var generator controller based on multi-mode extended state observation according to the present invention.
Fig. 2 is a simulation diagram of a dc side voltage waveform of a static var generator in an embodiment of the present invention.
Fig. 3 is a simulation diagram of the power factor of the static var generator in an embodiment of the present invention.
Fig. 4 is a simulation diagram of a voltage and current waveform of a static var generator according to an embodiment of the present invention.
Fig. 5 is a simulation diagram of the result of estimating the state quantity by the first multi-mode extended state observation unit according to the embodiment of the present invention.
Fig. 6 is a simulation diagram of the result of estimating the state quantity by the second multi-mode extended state observation unit according to the embodiment of the present invention.
Fig. 7 is a simulation diagram of the result of estimating the state quantity by the third multi-mode extended state observation unit according to the embodiment of the present invention.
FIG. 8 is a simulation diagram of a first multi-modal state of expansion observation unit estimating system uncertainty in an embodiment of the invention.
FIG. 9 is a simulation diagram of a second multi-modal state of expansion observation unit estimating system uncertainty item in an embodiment of the invention.
FIG. 10 is a simulation diagram of a system uncertainty estimation by multiple third modality extended state observation units according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
As shown in fig. 1, the invention provides a static var generator controller based on multi-mode extended state observation, which comprises a coordinate transformation unit, an active current controller, a direct current voltage controller, a reactive current controller and a SVPWM unit. The active current controller is composed of a first multi-mode extended state observation unit (shown as a multi-mode extended state observation unit 1 in the figure), a first monitor unit (shown as a monitor unit 1 in the figure), and a first controller unit (shown as a controller unit 1 in the figure). The dc voltage controller is composed of a second multimode extended state observation unit (shown as a multimode extended state observation unit 2 in the figure), a second monitor unit (shown as a monitor unit 2 in the figure), and a second controller unit (shown as a controller unit 2 in the figure). The reactive current controller is composed of a third multi-mode extended state observation unit (shown as a multi-mode extended state observation unit 3 in the figure), a third monitor unit (shown as a monitor unit 3 in the figure), and (shown as a controller unit 3 in the figure). The coordinate transformation unit consists of 3s/2r and 2r/2s coordinate transformation units, wherein the 3s/2r realizes three-phase-two-phase transformation, namely transformation between a three-phase static coordinate system A-B-C and a two-phase rotating coordinate system d-q, and the input of the three-phase static coordinate system A-B-C and the two-phase rotating coordinate system d-q is current i in a power grid a 、i b And i c Output as a current signal i which is required to be transformed into a two-phase rotating coordinate system d And i q ，i d Connected to the inputs of the multimode extended state observation unit 1 and the monitor unit 2, i q Is connected with the multi-mode expansion state observation unit 3 and the monitor unit 3; the 2r/2s coordinate transformation unit transforms the two-phase rotating coordinate system d-q and the two-phase static coordinate system alpha-beta, and the input is u output by the second controller unit d And u output from the third controller unit q 。
As shown in fig. 1, the output end of the multi-mode extended state observation unit 1 is connected with the monitor unit 1, the output end of the multi-mode extended state observation unit 2 is connected with the monitor unit 2, the output end of the monitor unit 1 is connected with the input end of the controller unit 1, and the output end of the monitor unit 2 is connected with the input end of the controller unit 2. The output end of the controller unit 2 is connected with the input end of the SVPWM unit after 2r/2s coordinate transformation; the output end of the multimode extended state observation unit 3 is connected with the input end of the monitor unit 3, and the output end of the monitor unit 3 is connected with the controller unit 3. U output from the controller unit 2 d And u output from the controller unit 3 q And the converted signal is connected with the input end of the SVPWM unit after 2r/2s conversion. The SVPWM unit generates a modulation signal to control the state of a switching tube in a main circuit of the static var generator. The SVPWM unit is a space voltage vector modulation unit.
Further, the mathematical model of the static var generator is as follows:
wherein e a ,e b ,e c Phase voltages, i, of the phases A, B, C of the network a ,i b ,i c For the phase currents of the phases A, B and C of the electric network, u dc Is the voltage of the direct current side of the static var generator, s a ,s b ,s c And (3) linearizing the mathematical model (1) for the switching function of the three-phase bridge through equivalent coordinate transformation to obtain the mathematical model of the static var generator under a two-phase rotating coordinate system:
wherein: wherein e d For the d-axis component, e, of the mains voltage q For the q-axis component, i, of the grid voltage d Is the d-axis component, i of the alternating current side current of the static var generator q Q-axis component, s of current on alternating side of static var generator d In d-axis for three-phase bridge switching functionComponent s of (2) q For components of the three-phase bridge switching function in the q-axis, u d ＝u dc s d For the d-axis component, u, of the ac side voltage of the static var generator q ＝u dc s q The q-axis component of the voltage of the alternating current side of the static var generator is L, the inductance value of the connecting reactor of the alternating current side of the static var generator, C, the energy storage capacitance value of the direct current side of the static var generator, R, the equivalent resistance value of the reactor and the switching element, u dc For the dc side voltage of SVG, ω is angular velocity, and ω=2pi f, f is grid frequency, and f=50 Hz.
The details of each functional unit are further described below.
A. Coordinate transformation unit
The coordinate transformation unit adopts a phase-locked loop technology to obtain a required phase signal to complete coordinate transformation. The coordinate transformation unit consists of 3s/2r and 2r/2s coordinate transformation units, wherein the 3s/2r realizes three-phase-two-phase transformation, namely transformation between a three-phase static coordinate system A-B-C and a two-phase rotating coordinate system d-q, and the input of the three-phase static coordinate system A-B-C and the two-phase rotating coordinate system d-q is current i in a power grid a 、i b And i c Output as a current signal i which is required to be transformed into a two-phase rotating coordinate system d And i q ，i d Connected to the inputs of the multimode extended state observation unit 1 and the monitor unit 2, i q Is connected with the multi-mode expansion state observation unit 3 and the monitor unit 3; the 2r/2s coordinate transformation unit realizes the transformation between the two-phase rotating coordinate system d-q and the two-phase static coordinate system alpha-beta, and the input is u output by the second controller unit d And u output from the third controller unit q 。
Taking the coordinate transformation of current as an example, the coordinate transformation from the three-phase stationary coordinate system to the α - β coordinate system is:
and then converting the alpha-beta coordinate system into a d-q coordinate system. The transformation equation is:
bringing equation (3) into equation (4) yields:
B. active current controller
The active current controller is composed of a multi-mode extended state observer unit 1, a monitor unit 1 and a controller unit 1.
B1, multimode extended state observation unit 1
The input of the multi-mode expansion state observation unit 1 is the d-axis component e of the power grid voltage d AC side current d-axis component i of static var generator d Dc side voltage u dc . Output is a pair status itemEstimate of +.>Estimate of external interference->To simplify the calculation, let->
Wherein,for the evaluation of the state item u +.>For the estimation of external interference, i e { 1..N } N is the number of observers, b 1i For controlling gain within a given error range, k 1 、k 2 Control parameter for first extended state observation unitA number.
B2, monitor unit 1
The input of the monitor unit 1 is the output of the multi-modal extended state observer 1Sum state quantity u i Outputs as the actual value of the selected control gain b 1 And disturbance->
The monitor signal is an exponentially weighted selection of the monitor signal output error associated with each observerNorms, which can be implemented as linear filters:
where i ε { 1..N }, λ 1 >0 is the design parameter, mu 1i (t) generating a weighted norm of the monitor signal for each observer.For the deviation value of the state quantity, u is the actual value of the state quantity, and the selected signal input quantity is the output +_of the multi-mode extended state observer 1>And the actual value of the state quantity, and different control gains b 1i Signal sigma 1 For selecting one observer from the N observers at each instant in time, minimizing its deviation value. The formula is as follows:
b3, controller unit 1
The input of the controller unit 1 is the reference voltage u on the DC side of the static var generator re f and monitor sheetThe optimal disturbance estimation and the optimal gain of the element 1 output. The output is current i d Reference current value i of (2) dref . The control law is as follows:
wherein,optimal disturbance estimation selected for the first monitor unit b 1 For the first optimum gain selected ω c1 For the first controller coefficient, u dc For the DC side voltage of SVG, u dcref For a given SVG dc side reference voltage.
C. DC voltage controller
The direct-current voltage controller is composed of a multi-mode extended state observer unit 2, a monitor unit 2, and a controller unit 2.
C1, multimode extended state observation unit 2
The input of the multimode extended state observation unit 2 is the d-axis component e of the voltage on the alternating current side of the static var generator d Current d-axis component i d . Output is the pair status item i di Estimate of (2)Estimate of external interference->The formula is as follows:
where i=1,.. 2i For controlling gain within a given error range, k 3 、k 4 Is a control parameter of the first extended state observation unit.
C2, monitor unit 2
The input of the monitor unit 2 is the output of the multi-modal extended state observer 2And state quantity i di Outputs as the actual value of the selected control gain b 2 And disturbance->
The monitor signal is an exponentially weighted selection of the monitor signal output error associated with each observerNorms, which can be implemented as linear filters:
where i ε { 1..N }, λ 2 >0 is the design parameter, mu 2i (t) generating a weighted norm of the monitor signal for each observer,is the deviation value of the state quantity, i d B is the actual value of the state quantity 2i Is the second control gain. The signal input quantity is selected to be the output of the multimode extended state observer 2>And state quantity i di Is different from the actual value of the control gain b 2i Signal sigma 2 For selecting one observer from the N observers at each instant in time, minimizing its deviation value. The formula is as follows:
c3, controller unit 2
The input of the controller unit 2 is the output i of the controller unit 1 dref And the optimal disturbance estimate and the optimal gain output by the monitor unit 2. And outputting the reference value as the d-axis component of the alternating-current side voltage of the static var generator. The control law is as follows:
wherein,b) optimal disturbance estimation selected for the monitor 2 Omega for the selected optimal gain c2 Is the controller coefficient.
D. Reactive current controller
The reactive current controller is composed of a multi-mode extended state observer unit 3, a monitor unit 3, and a controller unit 3.
D1, multimode extended state observation unit 3
The modal expansion state observation unit 3 inputs the voltage q-axis component e of the alternating current side of the static var generator q Current q-axis component i q . Output pair status item i qi Estimate of (2)Estimate of external interference->The formula is as follows:
where i=1,.. 3i For controlling gain within a given error range, k 5 、k 6 Is a control parameter of the first extended state observation unit.
D2, monitor unit 3
The input of the monitor unit 3 is the output of a multi-modal extended state observerAnd state quantity i qi Outputs as the actual value of the selected control gain b 3 And disturbance->
The monitor signal is an exponentially weighted selection of the monitor signal output error associated with each observerNorms, which can be implemented as linear filters:
where i ε { 1..N }, λ 3 >0 is the design parameter, mu 3i (t) generating a weighted norm of the monitor signal for each observer,for the deviation value of the state quantity, +.>I is the output of the third multi-modal extended state observer q B is the actual value of the state quantity 3i And is the third control gain. The signal input quantity is selected to be the output of the multimode extended state observer 3>And state quantity i qi Is different from the actual value of the control gain b 3i Signal sigma 3 For selecting one observer from the N observers at each instant in time, minimizing its deviation value. The formula is as follows:
d3, controller unit 3
The input of the controller unit 3 gives a reference component i to the ac side current q-axis of the static var generator qref And the optimal disturbance estimate and the optimal gain output by the monitor unit 3. The output is a reference value of the q-axis component of the ac side voltage of the static var generator. The design control rate is as follows:
wherein u is q For the q-axis voltage control law, i qref For current i q Is set to be equal to or greater than the reference current value of (c),b) optimal disturbance estimation selected for the monitor 3 Omega for the selected optimal gain c3 Is the controller coefficient.
E. SVPWM unit
The SVPWM unit input is u output by the direct current voltage control module d U, the output of the reactive current control module q U after 2r/2s conversion bet And u alf The output is a signal for driving the switching element to be turned on or off. The SVPWM unit adopts a space vector modulation technology to modulate a reference value of alternating-current side voltage of the static var generator into a signal for driving the switching element to be switched on and off, and sends the signal to the three-phase bridge circuit to control the switching element to be switched on and off.
The invention is further described below with respect to a specific application of a static var generator in reactive compensation. Fig. 1 is a schematic structural diagram of the present invention, wherein a model of a static var generator in a two-phase rotating coordinate system is:
the specific parameter is selected as that the energy storage capacitor at the direct current side is 1100 mu F, the inductance of the connecting reactor at the alternating current side is 5mH, and the equivalent resistance of the connecting reactor and the switching element is 0.1 omega. Firstly, the load is an inductive load with active power of 1000W and reactive power of 1000Var, and in order to observe the compensation capability and the dynamic compensation performance of the static Var generator under different loads, the load is switched to a capacitive load with the active power of 1000W and the reactive power of 1000Var at 0.6 s. The extended state observer employed in the control system satisfies formulas (6), (10) and (14), wherein the parameters of the extended state observer are: k (k) 1 ＝250,k 2 ＝25000，k 3 ＝300,k 4 ＝13000，k 5 ＝300,k 6 ＝1000。
The simulation results are shown in fig. 2-4. Fig. 2 is a waveform diagram of a dc side voltage of the static var generator, where the dc side voltage has a given value of 600V, and considering that in an actual experiment, an uncontrolled rectifying experiment is performed first, and in an uncontrolled rectifying experiment, the dc side voltage has a value of about 500V. The dc side voltage value was assigned to 500V at the beginning of the simulation. And at 0.6s, the load is changed from inductive load to capacitive load, and the direct current voltage fluctuates. Fig. 3 is a waveform diagram of the power factor of the static var generator, from which it can be seen that the present invention can substantially increase the power factor to around 1. The reactive power compensation effect is achieved. After 0.6s of load replacement, the power factor is restored to the vicinity of 1 after a short time of fluctuation. Fig. 4 is a waveform diagram of grid voltage and current, where the voltage and current are substantially in phase, and the static var generator may compensate for reactive power generated by the load.
As shown by simulation results, the designed multi-mode extended state observer can select the most suitable control algorithm in real time according to the actual running state of the system, and adjust the control gain. The monitor unit selects the parameters of the most suitable model, and selects proper time to switch, so as to realize the optimal combination among performance indexes reflecting the stability, accuracy and rapidity of the system. The method of increasing the number of observers is adopted to realize the selection of the parameters most suitable for the model, and the proper time is selected for switching, so that the optimal combination among performance indexes reflecting the stability, the accuracy and the rapidity of the system is realized. As shown in fig. 5-10, and sends the selected optimal value to the controller to complete the control task of the static var generator. The anti-interference capability of the system is improved, the design of the controller is simplified, and the design target is met.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (5)
1. A static var generator controller based on multi-modal extended state observations, comprising: the system comprises a coordinate transformation unit, an active current controller, a direct current voltage controller, a reactive current controller and an SVPWM unit;
the active current controller comprises a first multi-mode expansion state observation unit, a first monitor unit and a first controller unit; the direct-current voltage controller comprises a second multi-mode expansion state observation unit, a second monitor unit and a second controller unit; the reactive current controller comprises a third multimode expanded state observation unit, a third monitor unit and a third controller unit;
the coordinate transformation unit consists of a 3s/2r coordinate transformation unit and a 2r/2s coordinate transformation unit, the 3s/2r coordinate transformation unit is used for realizing transformation between a three-phase static coordinate system A-B-C and a two-phase rotating coordinate system d-q, and the input of the 3s/2r coordinate transformation unit is current i in a power grid a 、i b And i c Output as a current signal i which is required to be transformed into a two-phase rotating coordinate system d And i q Current signal i d Is connected with the input ends of the first multi-mode expanded state observation unit and the second monitor unit, i q Is connected with a third multi-mode expanded state observation unit and a third monitor unit 3; the 2r/2s coordinate transformation unit is used for transforming the two-phase rotating coordinate system d-q and the two-phase static coordinate system alpha-beta, and the input of the 2r/2s coordinate transformation unit is u output by the second controller unit d And u output from the third controller unit q ；
The output end of the first multi-mode expansion state observation unit is connected with the first monitor unit, and the output end of the first monitor unit is connected with the input end of the first controller unit;
the second multimode expanded state observation unitThe output end of the second monitor unit is connected with the input end of the second controller unit, and u is output by the second controller unit q 2r/2s coordinate transformation is carried out and then the SVPWM unit is connected with the input end of the SVPWM unit;
the output end of the third multimode expanded state observation unit is connected with the input end of the third monitor unit, the output end of the third monitor unit is connected with the third controller unit, and u is output by the third controller unit q 2r/2s conversion is carried out and then the converted signal is connected with the input end of the SVPWM unit;
the SVPWM unit generates a modulation signal to control the state of a switching tube in a main circuit of the static var generator, and the SVPWM unit is a space voltage vector modulation unit.
2. The static var generator controller based on multi-modal state-of-expansion observation according to claim 1, wherein the mathematical model of the static var generator in a two-phase rotational coordinate system is:
wherein e d For the d-axis component, e, of the mains voltage q For the q-axis component, i, of the grid voltage d Is the d-axis component, i of the alternating current side current of the static var generator q Q-axis component, s of current on alternating side of static var generator d Component in d-axis for three-phase bridge switching function, s q For components of the three-phase bridge switching function in the q-axis, u d ＝u dc s d For the d-axis component, u, of the ac side voltage of the static var generator q ＝u dc s q The q-axis component of the voltage of the alternating current side of the static var generator is L, the inductance value of the connecting reactor of the alternating current side of the static var generator, C, the energy storage capacitance value of the direct current side of the static var generator, R, the equivalent resistance value of the reactor and the switching element, u dc For the direct-current side voltage of SVG, ω is the angular velocity, ω=2pi f, f is the gridFrequency.
3. A static var generator controller based on multi-modal state-of-expansion observation according to claim 2, wherein said first multi-modal state-of-expansion observation unit is adapted to output a state term according to the following calculationEstimate of +.>And the estimated value of external interference ∈>Let->
Wherein,for the evaluation of the state item u +.>For the estimation of external interference, i e { 1..N } N is the number of observers, b 1i For controlling gain within a given error range, k 1 、k 2 Control parameters of the first extended state observation unit;
the first monitor unit is configured to select an exponentially weighted version of the monitor signal output error associated with each observer in accordance withNorms and by selectionThe observer with the smallest deviation value determines the selected control gain:
wherein i.e { 1..N }, λ 1 >0 is the design parameter, mu 1i (t) generating a weighted norm of the monitor signal for each observer,for the deviation value of the state quantity, +.>For the output of the first multi-modal extended state observer, u is the actual value of the state quantity, b 1i Is a first control gain;
the first controller unit is used for calculating the output current i according to the following d Reference current value i of (2) dref ：
Wherein,optimal disturbance estimation selected for the first monitor unit b 1 For the first optimum gain selected ω c1 For the first controller coefficient, u dc For the DC side voltage of SVG, u dcref For a given SVG dc side reference voltage.
4. A static var generator based on multi-modal extended state observation as claimed in claim 3A controller, wherein the second multi-mode extended state observation unit is used for outputting a pair of state items i according to the following calculation d Estimate of (2)And an estimate of external disturbances +.>
Wherein,for state item i d Estimated value of ∈10->I.e { 1..N } b, which is an estimate of the external interference 2i For controlling gain within a given error range, k 3 、k 4 Control parameters of the first extended state observation unit;
the second monitor unit is configured to select an exponentially weighted version of the monitor signal output error associated with each observer in accordance withNorm and determining the selected control gain by selecting the observer that minimizes the deviation value:
μ 2i (0)＝0
wherein i ε { 1..N }, λ 2 >0 is the design parameter, mu 2i (t) generating a weighted range of monitoring signals for each observerThe number of the product is the number,for the deviation value of the state quantity, +.>I is the output of the second multi-modal extended state observer d B is the actual value of the state quantity 2i Is a second control gain;
the second controller unit is used for calculating and outputting a reference value of the alternating-current side voltage d-axis component of the static var generator according to the following steps:
wherein u is d Is a reference value for the d-axis component of the ac side voltage of the static var generator,optimal disturbance estimation selected for the second monitor unit b 2 For the second optimum gain selected ω c2 Is the second controller coefficient.
5. The static var generator controller based on multi-modal state observation according to claim 4, wherein said third multi-modal state observation unit is configured to output a pair of state terms i according to the following calculation q Estimate of (2)And an estimate of external disturbances +.>
Wherein i ε { 1..N }, b 3i For controlling gain within a given error range, k 5 、k 6 Control parameters of the first extended state observation unit;
the third monitor unit is configured to select an exponentially weighted version of the monitor signal output error associated with each observer in accordance withNorm and determining the selected control gain by selecting the observer that minimizes the deviation value:
μ 3i (0)＝0
wherein i ε { 1..N }, λ 3 >0 is the design parameter, mu 3i (t) generating a weighted norm of the monitor signal for each observer,for the deviation value of the state quantity, +.>I is the output of the third multi-modal extended state observer q B is the actual value of the state quantity 3i Is a third control gain;
the third control unit is used for calculating and outputting a reference value of the alternating-current side voltage q-axis component of the static var generator according to the following steps:
wherein u is q For the ac side voltage q-axis component, i of a static var generator qref For current i q Is set to be equal to or greater than the reference current value of (c),optimal disturbance estimation selected for the third monitor unit b 3 For the third optimum gain selected ω c3 Is the third controller coefficient.
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