CN115102223B - SVG-equipped photovoltaic grid-connected system and control method for loop forming in system - Google Patents
SVG-equipped photovoltaic grid-connected system and control method for loop forming in system Download PDFInfo
- Publication number
- CN115102223B CN115102223B CN202210708583.8A CN202210708583A CN115102223B CN 115102223 B CN115102223 B CN 115102223B CN 202210708583 A CN202210708583 A CN 202210708583A CN 115102223 B CN115102223 B CN 115102223B
- Authority
- CN
- China
- Prior art keywords
- controller
- inverter
- grid
- svg
- control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000013016 damping Methods 0.000 claims abstract description 51
- 239000003990 capacitor Substances 0.000 claims description 32
- 238000000354 decomposition reaction Methods 0.000 claims description 23
- 239000011159 matrix material Substances 0.000 claims description 16
- 238000007493 shaping process Methods 0.000 claims description 13
- 238000004146 energy storage Methods 0.000 claims description 12
- 230000002068 genetic effect Effects 0.000 claims description 4
- 238000005457 optimization Methods 0.000 claims description 4
- 230000002829 reductive effect Effects 0.000 claims description 4
- 230000000087 stabilizing effect Effects 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 230000005611 electricity Effects 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims 1
- 230000010355 oscillation Effects 0.000 abstract description 20
- 230000002401 inhibitory effect Effects 0.000 abstract description 3
- 230000006641 stabilisation Effects 0.000 abstract 1
- 238000011105 stabilization Methods 0.000 abstract 1
- 238000010248 power generation Methods 0.000 description 12
- 230000004044 response Effects 0.000 description 8
- 230000001360 synchronised effect Effects 0.000 description 8
- 238000013461 design Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 238000004088 simulation Methods 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- 230000005764 inhibitory process Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 description 1
- 241001083847 Berberis Species 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
- H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/10—Flexible AC transmission systems [FACTS]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The invention discloses a photovoltaic grid-connected system with SVG and a control method for loop forming in the system.A controller is based on H ∞ loop forming control of an H ∞ control theory, a grid-connected inverter damping control module adopts a PI controller to respectively receive an actual value of inverter side direct current voltage and a reference value of inverter direct current side voltage, and outputs signals to be connected with an SPWM module through a current inner loop controller for control, a signal output end controlled by the SPWM module is connected with an inverter through a control system, and a compensation end of an SVG dynamic reactive compensation device is connected with a signal output end of an output circuit. The control method comprises loop forming, robust stabilization and controller forming. The control system provided by the invention has a simple structure, can effectively improve the damping characteristic of the vibration system, reduce the initial fluctuation amplitude of power and shorten the oscillation time, and the equipped SVG dynamic reactive power compensation device can effectively improve the capacity of inhibiting power oscillation and ensure the safe and stable operation of the weak grid-connected system. The control system is suitable for grid connection of large-scale photovoltaic power stations.
Description
Technical Field
The invention belongs to the field of grid connection of photovoltaic power generation, relates to a photovoltaic grid-connected inverter, in particular to a photovoltaic grid-connected system provided with SVG, and further provides a control method for loop forming in the photovoltaic grid-connected system provided with SVG.
Background
With the continuous consumption of energy, the exploration of new energy is continuously enhanced, and especially the electric energy is developed from the original traditional coal carbon power generation into modes of coexistence of various modes such as coal power generation, wind power generation, photovoltaic power generation and the like. Among them, the energy power generation represented by photovoltaic power generation is a green energy source existing in nature, and is being favored in recent years. Because the current power system in China is mature, the electric energy output by the photovoltaic power generation system is required to be integrated into the current power grid, and the electric energy output by the photovoltaic power generation system needs to be processed by the grid-connected system and then integrated into the power system so as to ensure the stability of the power system after grid connection.
At present, the photovoltaic power generation processes direct current generated by a photovoltaic cell panel through a grid-connected system, and three alternating currents synchronous with a power grid are finally formed and input into a power grid. The problem of power oscillation occurs when the large-scale photovoltaic power station is connected with the grid, and the stability of the grid system in the grid connection process cannot be guaranteed by a single control mode, so that the design of the photovoltaic grid-connected system is urgently needed, and the damping characteristic of the oscillation system can be effectively improved.
Disclosure of Invention
The invention aims to provide a photovoltaic grid-connected system with SVG (static var generator) so as to improve damping characteristics of an oscillating system and improve power inhibition capability.
The invention further aims to provide a control method for loop forming in the photovoltaic grid-connected system provided with SVG, which is based on H ∞ loop forming control of H ∞ control theory, so that the photovoltaic grid-connected system realizes compensation control of additional H ∞ damping.
The technical scheme adopted by the invention for realizing the purposes is as follows:
The H ∞ loop forming control based on the H ∞ control theory comprises a photovoltaic panel, a boost circuit, a maximum power point tracking control circuit, an inverter and an output circuit, wherein the maximum power point tracking control circuit is used for controlling the photovoltaic panel to generate power at a maximum power point, an output signal of the photovoltaic panel is connected to a three-phase power grid sequentially through the boost circuit, the inverter and the output circuit, the input end of the maximum power point tracking control circuit is connected with the output end of the photovoltaic panel, the output end of the maximum power point tracking control circuit is connected with the inverter, the grid-connected inverter damping control module comprises a grid-connected inverter damping control module and a SVG dynamic reactive compensation device, the grid-connected inverter damping control module comprises a decoupling capacitor, a PI controller, a current inner loop controller and an SPWM driving circuit, the decoupling capacitor is connected with the input end of the inverter in parallel, the signal input end of the PI controller receives the actual value of the DC voltage of the inverter side and the voltage reference value of the inverter, the signal output end of the PI controller outputs the parameter i dref current to a current inner loop controller, the voltage of the grid-connected with the current inner loop controller as the voltage inner loop of the inverter AC current of the inverter, and the current inner loop of the current inner loop controller is connected with the current inner loop controller through the decoupling capacitor and the current inner loop of the current controller;
And the compensation end of the SVG dynamic reactive power compensation device is connected with the signal output end of the output circuit.
As a limitation of the present invention: the boost circuit comprises a boost inductor and an energy storage capacitor which are connected in series, wherein the energy storage capacitor is connected in parallel with two ends of an output signal of the photovoltaic panel, and one end of the energy storage capacitor, which is connected with an output end of the positive electrode of the photovoltaic panel, is connected in series with the boost inductor.
As a further limitation of the invention: the maximum power point tracking control circuit comprises a solar controller, a seventh modem and a seventh switching tube, wherein the signal input end of the solar controller is connected with the negative electrode output of the photovoltaic panel, the output end of the solar controller is connected with the emission set of the seventh switching tube through the seventh modem, and the collector electrode of the seventh switching tube is connected with one end of the boost inductor which is not connected with the energy storage capacitor.
As a further definition of the invention: the series circuit of the decoupling capacitor and the diode is connected in parallel with two ends of the boost circuit, wherein one end of the decoupling capacitor is connected with the cathode of the diode, the anode of the diode is connected with the positive output end of the boost circuit, the other end of the decoupling capacitor is connected with the negative output end of the boost circuit, and the power end of the decoupling capacitor outputs the actual value of the direct-current side voltage;
The inverter is connected in parallel with two ends of the decoupling capacitor, the output circuit comprises an inversion side inductor and a network side inductor, and the output end of the inverter is sequentially connected with the inversion side inductor and the network side inductor in series and is connected with a three-phase power grid.
The invention also provides a loop forming control method in the photovoltaic grid-connected system provided with the SVG, and the control method for H ∞ loop forming control based on the H ∞ control theory comprises the following steps in sequence:
1) Loop forming: optimizing and selecting a front series weight function W 1、W2 and a rear series weight function W 1、W2 by utilizing a multi-objective genetic algorithm to carry out shaping fitting on an open loop function G SVG、GPV;
2) Robust tranquilization: setting G p(s)＝M-1(s) N(s) to satisfy M(s) M T(s)+N(s)NT(s) =i, where M(s), N(s) are defined as normalized left mutual mass decomposition of G p, I is an identity matrix, and calculating by the above relation with formula (13) to obtain a system maximum stability margin epsilon max:
Wherein K ∞(s) is a calm controller, N(s) M(s) H is a Hankle norm, I is a unit matrix, N(s) normalizes right mutual mass decomposition, M -1(s) is an inverse matrix of the normalized left mutual mass decomposition, M T(s) is a transpose matrix of the normalized left mutual mass decomposition, and N T(s) is a transpose of the normalized right mutual mass decomposition;
3) Shaping of the controller: and 3) finally determining an output feedback controller K(s) by utilizing the weight function selected in the optimization of the step 1) and the calm controller K ∞(s) obtained in the step 2), wherein the output feedback controller K(s) is obtained by a formula (17): k(s) =w 2(s)K∞(s)W1(s) (17).
As a definition of step 1) in the above method: in the step 1), in order to ensure control performance and robustness, the singular value curve needs to satisfy the principle that the low-frequency band high gain, the high-frequency band low gain and the crossing frequency are large enough; in order to make the singular value gain curve of the system after the shaping be a theoretical value, the selection conditions of the weight function include:
a) In the low frequency band, the maximum value of the minimum singular value curve R 1 is corresponding to the R 1 which is more than 30dB;
b) In the high frequency band, the minimum value of the maximum singular value curve R 2 is corresponding to the minimum value, and the minimum value meets the requirement that-R 2 is less than 20dB;
c) When the frequency of the intermediate frequency band is reduced, the maximum value of the difference value between the singular value R 3 corresponding to the average singular value curve at the frequency of 1rad/s and the singular value R 4 corresponding to the average singular value curve at the frequency of 10rad/s meets the requirement of (R 3-R4) >20dB;
d) When the frequency is traversed, the minimum singular value curve is at the maximum value of the singular value R 5 corresponding to 1rad/s, and R 5 is satisfied to be more than 5dB.
As another limitation to step 1) in the above method: the front and rear series weight functions W 1、W2 selected in the step 1) are obtained by the formula (11):
where s is the Laplacian in the transfer function, and the system after loop shaping is:
GP＝W2(s)G(s)W1(s) (12)。
As a definition of step 2) in the above method: the calm controller K ∞(s) in step 2) is obtained by the formula (14):
Where M -1(s) is the inverse of the normalized left-prime decomposition and ε is the inverse of an infinite decimal.
This is another limitation of step 2) in the above method: the obtained controller designed in the step 2) can calm a disturbance set model of the controlled object through mutual quality factor uncertainty decomposition, wherein the mutual quality factor uncertainty disturbance model set is as follows:
GΔ＝(M+ΔM)-1(N+ΔN) (15)，
Wherein delta M、ΔN is the uncertainty factor of the controlled system, and the relation between the two factors satisfies the formula (16):
Wherein RH ∞ is the space formed by the physical function matrix of the electrodeless point on the real axis of coordinates.
Compared with the prior art, the technical proposal adopted by the invention has the following technical progress:
(1) The SVG dynamic reactive power compensation device is arranged, the SVG dynamic reactive power compensation device is cooperated with a photovoltaic power station, then the H ∞ loop forming control based on the H ∞ control theory is utilized, damping support can be provided for a power grid, meanwhile, the reactive power supporting function of the SVG dynamic reactive power compensation device configured by the photovoltaic power station is fully volatilized, and further, the controller K SVG with excellent design robustness performance can further remarkably improve the damping characteristic of the integration of the photovoltaic power station into a weak power grid through additional reactive voltage adjustment, the power oscillation inhibiting capability of the system is forcefully improved, and the safe and stable operation of the weak grid-connected system is ensured.
(2) The invention is provided with a maximum power point tracking control circuit, and an SPWM signal is obtained according to direct-current voltage and direct-current emitted by the photovoltaic panel, and the fuel control controls the on-off of the switching tube by using the SPWM signal, so that the photovoltaic panel is controlled to generate electricity to work at the maximum power point.
(3) The control method of loop forming of the invention provides the concept of infinite number N(s) M(s) H, ensures that the norm of the disturbance quantity borne by the designed K ∞ controller system to the output quantity is minimum through a mutual mass decomposition method, and is a strong robust stable design method with good control performance in the modern industrial field.
In summary, the control system disclosed by the invention has a simple structure, the damping characteristic of the vibration system can be effectively improved, the initial fluctuation amplitude of power is reduced, the oscillation time is shortened, and the provided SVG dynamic reactive power compensation device can effectively improve the capacity of inhibiting power oscillation and ensure the safe and stable operation of a weak grid-connected system. The control system is suitable for grid connection of large-scale photovoltaic power stations.
Drawings
FIG. 1 is a schematic circuit diagram of embodiment 1 of the present invention;
FIG. 2 is a schematic circuit diagram of embodiment 2 of the present invention;
FIG. 3 is a graph showing the singular value characteristic curve after loop shaping obtained based on NSGA-II algorithm in the embodiment 3 of the present invention;
FIG. 4 is a model of the mutual prime factor uncertainty decomposition in example 3 of the present invention;
FIG. 5 is a simulation equivalent circuit diagram of a Meng Xi grid 2 area 4 machine system constructed in embodiment 4 of the invention;
FIG. 6 is a schematic block diagram of the damping control of the PV supplemental H ∞ in example 4 of the present invention;
FIG. 7 is a schematic block diagram of SVG additional H ∞ damping control in embodiment 4 of the present invention;
FIG. 8 is a graph showing the active power versus the tie line for additional control of the photovoltaic power plant of example 4 of this invention;
FIG. 9 is a comparison curve of the speed difference response of the generator G 1′、G2' in example 4 of the present invention;
FIG. 10 is a graph showing the active response of the photovoltaic power plant in combination with SVG additional control links in example 4 of the present invention;
FIG. 11 is a graph showing the comparison of the speed difference response of the photovoltaic power plant in cooperation with SVG additional control G 1′、G3' in example 4 of the present invention;
fig. 12 is a voltage response curve of the photovoltaic power station in cooperation with SVG additional control grid-connected bus in embodiment 4 of the present invention.
Detailed Description
The invention will be better explained by the following detailed description of the embodiments with reference to the drawings.
Example 1 photovoltaic grid-connected System with SVG
The "front", "rear", "left" and "right" in this embodiment are defined for convenience of description, and do not limit the scope of the present invention.
The embodiment provides a photovoltaic grid-connected system with additional resistance control, which is based on H ∞ loop forming control of H ∞ control theory and comprises
This is shown in FIG. 1 and comprises:
1. the photovoltaic panel PV is a photovoltaic power generation panel in the prior art, and two ends of the photovoltaic panel PV are respectively provided with an anode output end and a cathode output end.
2. And the boosting circuit is used for boosting the direct-current voltage U v generated by the photovoltaic panel PV and converting the direct-current voltage U v into the rated voltage of the inverter. The boost circuit in this implementation is composed of a boost inductor L v and an energy storage capacitor C v, where the energy storage capacitor C v is connected in parallel to two ends of the output signal of the photovoltaic panel PV, and one end of the energy storage capacitor C v connected to the positive output end of the photovoltaic panel PV is connected in series with the boost inductor L v.
3. The inverter is used for converting the input direct current into three alternating currents, and the inverter in the embodiment adopts an inverter in the prior art, namely as shown in fig. 1, and comprises a first switching tube V 1 to a sixth switching tube V 6, and a diode is connected in series between a collector and an emission set of each switching tube.
4. And the output circuit is used for processing the three alternating currents converted by the inverter and then connecting the processed alternating currents to the three power grids. The output circuit in this embodiment includes an inverter side inductor L p and a network side inductor L m, where the output end of the inverter is serially connected with the inverter side inductor and the network side inductor in sequence and then connected with a three-phase power grid. In order to ensure that the output voltage is not interfered, the output circuit further comprises a filter, and a signal output end of the filter is connected to a line connected with the inverter side inductor L p and the network side inductor L m.
5. And the maximum power point tracking control circuit is used for controlling the photovoltaic panel PV power generation work to be at the maximum power point. The maximum power point tracking control circuit in this embodiment includes a solar controller MPPT, a seventh modem SPWM7, and a seventh switching tube V 7, where a signal input end of the solar controller MPPT is connected to a negative output of the photovoltaic panel PV, an output end of the solar controller MPPT is connected to an emission set of the seventh switching tube V 7 through the seventh modem SPWM7, and a collector of the seventh switching tube V 7 is connected to a boost inductor L v and is not connected to one end of the energy storage capacitor C v.
6. The grid-connected inverter damping control module comprises a decoupling capacitor C dc, a PI controller, a current inner loop controller and an SPWM driving circuit, wherein one end of the decoupling capacitor C dc is connected with the negative electrode output end of the photovoltaic panel PV, the other end of the decoupling capacitor C dc is connected with the negative electrode output end of the photovoltaic panel PV through a first diode VD1, and meanwhile, the decoupling capacitor C dc is connected with the input end of the inverter in parallel; the signal input end of the PI controller receives the actual value U dc of the DC voltage at the inverter side through a decoupling capacitor C dc, the signal input end of the PI controller also receives the reference value U dcref of the voltage at the DC side of the inverter at the same time, the signal output end of the PI controller is connected with the signal input end of the current inner loop controller, meanwhile, the signal input end of the current inner loop controller also receives the AC voltage and the current U d、Uq、Id、Iq of the grid-connected system, and the AC voltage and the current U d、Uq、Id、Iq of the grid-connected system are both supplied to the current inner loop controller as the active and reactive decoupling of the current inner loop; the output signal of the current inner loop controller is connected with the inverter through the SPWM driving circuit.
The SPWM driving circuit in this embodiment includes first to sixth modems SPWM1 to SPWM6, each of which controls a switching tube in the inverter correspondingly. The inverter-based SPWM driving circuit performs grid-connected control on the embodiment.
7. And the SVG dynamic reactive power compensation device is used for actively tracking and compensating the grid-connected system. In this embodiment, the compensation end of the SVG dynamic reactive compensation device is connected to the signal output end of the output circuit.
The control principle of the embodiment is as follows: the inverter side direct current voltage actual value U dc and the inverter side direct current voltage reference value U dcref are used as an outer ring to be input into a PI controller, and the output i dref is used as a current inner ring command value to maintain the constant direct current side voltage after the control of the PI controller; meanwhile, the current inner loop controller recognizes and takes the voltage and the current U d、Uq、Id、Iq at the alternating-current side of the grid-connected system as the active and reactive decoupling control input values of the current inner loop, and finally, the inverter triggers the SPWM driving circuit to carry out grid-connected control.
Example 2 grid-connected Circuit with photovoltaic grid-connected System provided with SVG
In this embodiment, the photovoltaic grid-connected system provided with the SVG in embodiment 1 is integrated into a power grid, a specific grid-connected circuit is shown in fig. 2, after the direct current signal obtained by the photovoltaic panel PV is converted by the inverter, the direct current signal is connected to the grid through the first step-up transformer, and the compensation signal of the SVG dynamic reactive compensation device is connected to the voltage grid-connected terminal through the second step-up transformer. G 1 in the figure is a synchronous generator set; g 2 is an infinite system; u g is grid-connected point voltage of the photovoltaic power station; e 1 is the transient potential of G 1; e 2 is the G 2 terminal voltage; θ is the phase angle difference of E 1 and U g; delta is the phase angle difference between E 1 and E 2; x 1、 x2 is the line reactance.
Wherein, the synchronous generator set G 1 outputs currentInput current of infinity system G 2 The method is obtained by the formula (1):
from this, the power P 2 which is input into the infinite system G 2 after the power P 1 generated by the synchronous generator set G 1 is connected to the photovoltaic power station is obtained by using the formula (2):
and the small disturbance equation of the synchronous machine of the second-order classical model is that:
HGp2Δδ+DpΔδ+ΔpG＝0 (3)，
wherein H G is an inertia coefficient, p is a differential operator, D is a damping coefficient, delta is a power angle difference, and delta p G is an active power difference.
The small perturbation equation linearization of equation (2) under initial conditions is:
Wherein Δp 1 is the power variation value of the generator set G 1, Δp 2 is the mahonia variation value of the infinity system G 2, θ 0 is the initial value of the phase angle difference, Δθ is the increment of the phase angle difference, δ 0 is the initial value of the phase angle difference, and Δδ is the power angle difference.
Considering the additional damping control of the photovoltaic power plant, it can be seen that:
Wherein: Δp g is the active increment, K pv is the damping control coefficient of the photovoltaic inverter, the voltage amplitude of the infinity system G 2 is set to be constant, i.e. Δe 2 =0, and then the voltage additional adjustment Δu g of the SVG dynamic reactive power compensation device is as follows
Wherein K SVG is an additional reactive power adjustment coefficient of the SVG dynamic reactive power compensation device,
Considering the rotor dynamic expression of the synchronous machine linearization, the following can be obtained by combining the formula (3):
Wherein DeltaP E is electromagnetic torque, deltaP m is mechanical torque, and then the increment equation of the infinity system G 2 is calculated
The power balance relation among the synchronous machine, the photovoltaic and the large power grid can be known:
ΔP2＝ΔP1+ΔPg (9)，
The linearization equation after the additional damping modulation of the photovoltaic power station collaborative SVG dynamic reactive power compensation device is obtained by bringing the formulas (5) and (6) into the formula (8) in combination with the formula (9) is as follows:
As can be seen from the formula (10), the photovoltaic power station additionally controls through the direct-current voltage outer ring of the inverter, designs a controller K PV meeting the requirement, and can provide damping support for the power grid; meanwhile, the reactive power supporting function of the SVG dynamic reactive power compensation device configured by the photovoltaic power station is fully exerted, the controller K SVG with excellent robust performance is designed, the damping characteristic of the photovoltaic power station integrated with a weak power grid can be further remarkably improved through additional passive voltage adjustment, the power oscillation capacity of the suppression system is forcefully improved, and the safe and stable operation of the weak grid-connected system is ensured.
Example 3A method of Loop formation control
A loop forming control method, which is the loop forming control method with SVG photovoltaic grid-connected system described in embodiment 1, and the control method based on H ∞ loop forming control of the H ∞ control theory, includes the following steps performed in order:
1) Loop forming: the front and rear series weight functions W 1、W2 are selected to perform shaping fit on the open loop function G SVG、GPV, and in order to avoid inaccuracy caused by the weight functions selected by artificial experience, the weight function parameters W 1、W2 are optimized and selected by utilizing a multi-objective genetic (NSGA-II) algorithm in the step.
The front and rear series weight functions W 1、W2 selected in this step are obtained by the formula (11):
Where s is the Laplacian in the transfer function, and the system after loop shaping is: g P＝W2(s)G(s)W1(s) (12).
The NSGA-II algorithm in the step is a non-dominant ranking genetic algorithm for balancing multi-objective parameter optimization based on elite strategy, and has the characteristics of high population ratio and high rapid dominant efficiency. Considering control performance and robustness, the singular value curve should satisfy the principles of high gain in low frequency band, low gain in high frequency band, and sufficiently large crossing frequency, so that the singular value gain curve of the system after shaping is a theoretical value, and the selection conditions of the weight function in this embodiment are as follows:
a) In the low frequency band, the maximum value of a minimum singular value curve R 1 at the low frequency (10 -3 rad/s) meets R 1 >30dB;
b) At high frequency (10 3 rad/s) the minimum value of the maximum singular value curve R 2, at high frequency, satisfies-R 2 <20dB.
C) The maximum value of the difference value between the singular value R 3 corresponding to the average singular value curve at the descending frequency of the middle frequency band and the singular value R 4 corresponding to the frequency of 10rad/s respectively meets (R 3-R4) >20dB.
D) When the frequency is traversed, the minimum singular value curve is at the maximum value of the singular value R 5 corresponding to 1rad/s, and R 5 is satisfied to be more than 5dB.
The singular value characteristic curve pair after loop shaping, which is obtained based on NSGA-II algorithm, is shown in figure 3, and the figure shows that the gain of the shaping system in a low frequency band is more than 30dB, thereby meeting the advantages of good tracking performance and strong disturbance rejection capability; the slope of-60 dB/dec is reduced in the high frequency band, so that the quick response of the system is ensured; the slope is-20 dB/dec when the singular value curve passes through 0dB, so that the steady-state performance is ensured. Therefore, the design requirement is met.
2) Robust tranquilization: setting G p(s)＝M-1(s) N(s) to satisfy M(s) M T(s)+N(s)NT(s) =i, where M(s), N(s) are defined as normalized left mutual mass decomposition of G p, I is an identity matrix, and calculating by the above relation with formula (13) to obtain a system maximum stability margin epsilon max:
Wherein K ∞(s) is a calm controller, N(s) M(s) H is a Hankle norm, I is a unit matrix, N(s) normalizes right inter-mass decomposition, M -1(s) is an inverse matrix of the normalized left inter-mass decomposition, M T(s) is a transpose matrix of the normalized left inter-mass decomposition, and N T(s) is a transpose of the normalized right inter-mass decomposition.
Studies have shown that when ε max takes a value within [0.2,1], robust performance is met so that the ballast controller K ∞(s) can be found by equation (14):
wherein KQ is reactive compensation gain, p is differential operator, and delta is power angle difference.
The model of the disturbance set of the designed controller for stabilizing the controlled object through the mutual quality factor uncertainty decomposition is shown in fig. 4, wherein the mutual quality factor uncertainty disturbance model set is as follows:
GΔ＝(M+ΔM)-1(N+ΔN) (15)，
Wherein delta M、ΔN is the uncertainty factor of the controlled system, and the relation between the two factors satisfies the formula (16):
Wherein RH ∞ is the space formed by the physical function matrix of the electrodeless point on the real axis of coordinates.
3) Shaping of the controller: and 3) finally determining an output feedback controller K(s) by utilizing the weight function selected in the optimization of the step 1) and the calm controller K ∞(s) obtained in the step 2), wherein the output feedback controller K(s) is obtained by a formula (17): k(s) =w 2(s)K∞(s)W1(s) (17).
Example 4 simulation analysis
The embodiment relies on DIGSILENT platform to complete the construction of the additional damping control photovoltaic grid-connected system of the embodiment 1 incorporated in the Mongolian power grid 4 machine 2 region system, the constructed model is specifically shown in fig. 5, the photovoltaic power station with additional damping control is integrated with SVG into the power grid through a bus 6 after inversion (parameters see annex A), and the input signal of the damping controller is the angular speed deviation delta omega S of the generator G 1′、G3'. The active maximum power of the photovoltaic power station in a normal mode is 250MW. Setting the initial value of the irradiation intensity of a power station to 800W/m 2, wherein PSS is not arranged in a synchronous generator set, and the unit capacity is 900 MW; the transmission power from zone 1 to zone 2 is normally 220MW.
Appendix A
Main parameter 1 of photovoltaic Power plant
Tab.A Main parameters of photovoltaic power station
The 4-machine 2 area system shown in fig. 5 is identified by using a TLS-ESPRIT algorithm to identify the oscillation mode of the system. And respectively taking the generator G 1′、G3' as an excitation point, and identifying that a section oscillation mode with the damping ratio of 0.71HZ of 4.28% and a local oscillation mode with the damping ratio of 0.71HZ of 4.25% exist in the region 1 and the region 2.
1. Photovoltaic and SVG additional H ∞ damping controller design
After the built system enters steady-state operation, step disturbance is set at the voltage reference value of the fixed direct current side of the inverter, an open loop transfer function G PV is obtained as a controlled object through identification of a TLS-ESPRIT algorithm and reduction of the step through a balanced cut-off method, and the open loop transfer function G PV is obtained by the formula (18):
In this embodiment, the weight function formula (11) optimized by NSGA-II algorithm is adopted to perform H ∞ loop forming, then MATLAB loop forming tool box is utilized to obtain the maximum robust stability margin epsilon ∞ = 0.42506 of the system, the additional H ∞ damping controller K PV of the photovoltaic inverter is obtained through the formula (14), the schematic diagram of the damping controller K PV is shown in fig. 6, the schematic diagram of the additional damping controller of the obtained SVG dynamic reactive power compensation device is shown in fig. 7, and the coefficient K PV(s) of the damping controller K PV is obtained by the formula (19):
Appendix A
In order to further fully utilize the reactive power flexible regulation advantage of the SVG dynamic reactive power compensation device, referring to the design method of the photovoltaic panel PV damping controller, as shown in FIG. 7, a voltage loop additional H ∞ damping controller of the SVG dynamic reactive power compensation device is designed to effectively inhibit power oscillation. And selecting the same weight function to perform H ∞ loop forming, and introducing epsilon ∞ = 0.36985 into a formula (14) to obtain a coefficient K SVG(s) of an additional H ∞ damping controller K SVG of the SVG inverter, wherein the coefficient K SVG(s) is as shown in a formula (20):
Where s is the Laplacian in the transfer function.
2. Photovoltaic additional damping control verification
When the photovoltaic power station works normally under the working condition that the illumination intensity is 1500W/m 2 and the temperature is 25 ℃; setting the sending end node 11 in fig. 5 to generate three-phase indirect grounding instantaneous disturbance at 1.8s, and eliminating the disturbance after 0.05 s; the simulation photovoltaic inverter suppresses the effect of system power oscillation under the condition of no additional control and additional H ∞ damping control, meanwhile, the robustness performance of the simulation photovoltaic inverter is verified by comparing a traditional PID controller with a designed H ∞ damping controller, and fig. 8 and 9 are respectively comparison curves of the transmission power of a connecting line and the rotating speed difference response of a generator G 1′、G3' under various control modes. As can be seen from fig. 8 and 9, no additional control is required, and a long decay time is required for the link transmission power and the generator power angle difference under fault disturbance.
And comparing the PID control with the H ∞ control of the photovoltaic power station: the active oscillation of the connecting line is effectively restrained at 15s and 12s respectively, the rotation speed difference of the generator G 1′、G3' tends to be stable at 16s and 13s respectively, and finally, the additional controller of the photovoltaic power station can improve the damping characteristic of the system, but the control performance and the robustness of the H ∞ controller are stronger, and the power oscillation restraining capability is superior to that of the traditional control method.
3. Photovoltaic collaborative SVG additional damping control verification
And under the same disturbance setting, the effectiveness of the SVG dynamic reactive power compensation device in adding the H ∞ damping controller and controlling in cooperation with the photovoltaic power station is verified under the same disturbance setting by respectively adding the traditional PID controller and the H ∞ damping controller at the photovoltaic power station and the SVG reactive power control position under the working conditions that the illumination intensity is 1500W/m < 2 > and the temperature is 25 ℃. Fig. 10, fig. 11, and fig. 12 are graphs showing the transmission power of the tie line, the rotational speed difference response of the generator G 1′、G3', and the bus voltage response of the grid-connected point in various control modes, wherein PID/PID control indicates photovoltaic and SVG are both added with conventional PID damping controllers, PID/H ∞ indicates photovoltaic PID control, SVG is H ∞ control, and H ∞/H∞ indicates photovoltaic. The observed quantity is the tie line power and the G 1′、G3' rotation speed difference.
As can be seen from fig. 10 and fig. 11, in the photovoltaic additional PID damping controller mode, the additional damping controller is configured on the SVG power control loop, so that the stability of the system under oscillation can be further improved, and the stability can be obtained by analysis: the system oscillation inhibition capability of the photovoltaic and SVG respectively added with PID and H ∞ damping controllers is better than that of the photovoltaic and SVG in both PID control modes; but if both photovoltaic and SVG are added with a robust H ∞ damping controller, this is clearly the most effective method of suppressing system power oscillations. In fig. 12, it is shown that, in the H ∞ controller mode, the additional control of the photovoltaic collaborative SVG effectively ensures the stability of the grid-connected bus voltage while improving the damping capability, and the collaborative control mode provides a strong and reliable dynamic stable supporting capability for the power grid.
The simulation demonstration shows that the photovoltaic and SVG additional H ∞ damping controllers can improve the damping characteristic of the oscillation system, and are superior to the traditional PID controllers in aspects of reducing the initial fluctuation amplitude of power, shortening the oscillation time and the like. Aiming at a photovoltaic grid-connected system provided with SVG, the power inhibition capability of the photovoltaic collaborative SVG additional H ∞ damping controller is obviously stronger than that of a single control mode.
The above description is only the best description of the present embodiment and does not constitute a limitation on the scope of the invention.
Claims (10)
1. The H ∞ loop forming control based on the H ∞ control theory comprises a photovoltaic panel, a boost circuit, a maximum power point tracking control circuit for controlling the photovoltaic panel to generate electricity and work at a maximum power point, an inverter and an output circuit, wherein an output signal of the photovoltaic panel is connected to a three-phase power grid sequentially through the boost circuit, the inverter and the output circuit, an input end of the maximum power point tracking control circuit is connected with an output end of the photovoltaic panel, an output end of the maximum power point tracking control circuit is connected with the inverter, the SVG dynamic reactive compensation device is characterized by further comprising a grid-connected inverter damping control module, the grid-connected inverter damping control module comprises a decoupling capacitor, a PI controller, a current inner loop controller and an SPWM driving circuit, wherein the decoupling capacitor is connected in parallel with the input end of the inverter, the signal input end of the PI controller is used for respectively receiving the actual value of the direct-current voltage at the inverter side and the reference value of the voltage at the direct-current side, the output end of the signal output end of the PI controller is used for outputting reference current to the current inner loop controller, the voltage and the current at the alternating-current side of the photovoltaic grid-connected system are used as active and reactive decoupling liquid of the current inner loop and are transmitted to the input end of the current inner loop controller, and the signal output end of the current inner loop controller is controlled and connected with the inverter through the SPWM module to drive and simultaneously output the direct-current voltage compensation value of the inverter to the PI controller;
And the compensation end of the SVG dynamic reactive power compensation device is connected with the signal output end of the output circuit.
2. The photovoltaic grid-connected system with the SVG according to claim 1, wherein the boost circuit comprises a boost inductor and an energy storage capacitor connected in series, the energy storage capacitor is connected in parallel with two ends of the output signal of the photovoltaic panel, and one end of the energy storage capacitor connected with the positive output end of the photovoltaic panel is connected in series with the boost inductor.
3. The photovoltaic grid-connected system with SVG according to claim 2, wherein the maximum power point tracking control circuit comprises a solar controller, a seventh modem and a seventh switching tube, the signal input end of the solar controller is connected with the negative output of the photovoltaic panel, the output end of the solar controller is connected with the emission set of the seventh switching tube through the seventh modem, and the collector electrode of the seventh switching tube is connected with one end of the boost inductor which is not connected with the energy storage capacitor.
4. The photovoltaic grid-connected system with SVG according to claim 3, wherein the series circuit of the decoupling capacitor and the diode is connected in parallel to two ends of the boost circuit, one end of the decoupling capacitor is connected with the cathode of the diode, the anode of the diode is connected with the positive output end of the boost circuit, the other end of the decoupling capacitor is connected with the negative output end of the boost circuit, and the power end of the decoupling capacitor outputs the actual value of the dc side voltage;
The inverter is connected in parallel with two ends of the decoupling capacitor, the output circuit comprises an inversion side inductor and a network side inductor, and the output end of the inverter is sequentially connected with the inversion side inductor and the network side inductor in series and is connected with a three-phase power grid.
5. The method for loop forming control in a photovoltaic grid-connected system provided with SVG according to any one of claims 1 to 4, wherein the control method for H ∞ loop forming control based on the H ∞ control theory comprises the following steps, which are sequentially performed:
1) Loop forming: optimizing and selecting a front series weight function W 1、W2 and a rear series weight function W 1、W2 by utilizing a multi-objective genetic algorithm to carry out shaping fitting on the open loop function G SVG、GPV;
2) Robust tranquilization: setting G p(s)＝M-1(s) N(s) to satisfy M(s) M T(s)+N(s)NT(s) =i, where M(s), N(s) are defined as normalized left mutual mass decomposition of G p, I is an identity matrix, and calculating by the above relation with formula (13) to obtain a system maximum stability margin epsilon max:
Wherein K ∞(s) is a calm controller, N(s) M(s) H is a Hankle norm, I is an identity matrix, N(s) normalizes right mutual mass decomposition, M -1(s) is an inverse matrix of the normalized left mutual mass decomposition, M T(s) is a transpose matrix of the normalized left mutual mass decomposition, and N T(s) is a transpose of the normalized right mutual mass decomposition;
3) Shaping of the controller: and 3) finally determining an output feedback controller K(s) by using the weight function selected in the optimization of the step 1) and the calm controller K ∞(s) obtained in the step 2), wherein the output feedback controller K(s) is obtained by a formula (17): k(s) =w 2(s)K∞(s)W1(s) (17).
6. The method for loop forming control according to claim 5, wherein in step 1), in order to ensure control performance and robustness, the singular value curve is required to satisfy the principles of high gain in low frequency band, low gain in high frequency band, and sufficiently large crossover frequency; in order to make the singular value gain curve of the shaped system be a theoretical value, the selection conditions of the weight function include:
a) In the low frequency band, the maximum value of the minimum singular value curve R 1 is corresponding to the R 1 which is more than 30dB;
b) In the high frequency band, the minimum value of the maximum singular value curve R 2 is corresponding to the minimum value, and the minimum value meets the requirement that-R 2 is less than 20dB;
c) When the frequency of the intermediate frequency band is reduced, the maximum value of the difference value between the singular value R 3 corresponding to the average singular value curve at the frequency of 1rad/s and the singular value R 4 corresponding to the average singular value curve at the frequency of 10rad/s meets the requirement of (R 3-R4) >20dB;
d) When the frequency is traversed, the minimum singular value curve is at the maximum value of the singular value R 5 corresponding to 1rad/s, and R 5 is satisfied to be more than 5dB.
7. The method of loop forming control according to claim 5 or 6, wherein the front and rear series weight functions W 1、W2 selected in step 1) are obtained by the formula (11):
Wherein S is the following are all the following;
The system after loop formation is as follows: g P＝W2(s)G(s)W1(s) (12).
8. The method of loop forming control according to claim 7, wherein the stabilizing controller K ∞(s) in step 2) is obtained by the formula (14):
Where M -1(s) is the inverse of the normalized left-prime decomposition and ε is the inverse of an infinite decimal.
9. The method according to claim 6 or 8, wherein the resulting controller designed in step 2) is capable of stabilizing the disturbance set model of the controlled object by means of a mutual prime factor uncertainty decomposition, wherein the mutual prime factor uncertainty disturbance model set is:
GΔ＝(M+ΔM)-1(N+ΔN) (15)，
wherein delta M、ΔN is the uncertainty factor of the controlled system, and the relation between the two factors satisfies the formula (16):
Wherein RH ∞ is the space formed by the physical function matrix of the electrodeless point on the real axis of coordinates.
10. The method of loop forming control according to claim 7, wherein the resulting controller designed in step 2) is capable of stabilizing a disturbance set model of the controlled object by a mutual prime factor uncertainty decomposition, wherein the mutual prime factor uncertainty disturbance model set is:
GΔ＝(M+ΔM)-1(N+ΔN) (15)，
wherein delta M、ΔN is the uncertainty factor of the controlled system, and the relation between the two factors satisfies the formula (16):
Wherein RH ∞ is the space formed by the physical function matrix of the electrodeless point on the real axis of coordinates.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210708583.8A CN115102223B (en) | 2022-06-21 | 2022-06-21 | SVG-equipped photovoltaic grid-connected system and control method for loop forming in system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210708583.8A CN115102223B (en) | 2022-06-21 | 2022-06-21 | SVG-equipped photovoltaic grid-connected system and control method for loop forming in system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115102223A CN115102223A (en) | 2022-09-23 |
| CN115102223B true CN115102223B (en) | 2024-08-16 |
Family
ID=83292024
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210708583.8A Active CN115102223B (en) | 2022-06-21 | 2022-06-21 | SVG-equipped photovoltaic grid-connected system and control method for loop forming in system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115102223B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106208092A (en) * | 2016-09-18 | 2016-12-07 | 广东电网有限责任公司电力科学研究院 | A kind of photovoltaic DC-to-AC converter reactive power regulating power analyzes method |
| CN112688337A (en) * | 2019-10-17 | 2021-04-20 | 华北电力大学（保定） | Photovoltaic grid-connected system subsynchronous oscillation suppression method based on static var generator |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10797615B2 (en) * | 2018-02-18 | 2020-10-06 | Mohit CHHABRA | Uncertainty based controller design for an inverter |
-
2022
- 2022-06-21 CN CN202210708583.8A patent/CN115102223B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106208092A (en) * | 2016-09-18 | 2016-12-07 | 广东电网有限责任公司电力科学研究院 | A kind of photovoltaic DC-to-AC converter reactive power regulating power analyzes method |
| CN112688337A (en) * | 2019-10-17 | 2021-04-20 | 华北电力大学（保定） | Photovoltaic grid-connected system subsynchronous oscillation suppression method based on static var generator |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115102223A (en) | 2022-09-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109274135B (en) | Reactive power optimization control method based on active power output of photovoltaic power station | |
| CN106410839A (en) | Active and reactive current coordination control-based photovoltaic grid-connected inverter control method | |
| CN111900710B (en) | Grid-connected direct-current micro-grid coordination control method | |
| Behera et al. | Coordinated power management of a laboratory scale wind energy assisted lvdc microgrid with hybrid energy storage system | |
| Nasef et al. | Optimal power management and control of hybrid photovoltaic-battery for grid-connected doubly-fed induction generator based wind energy conversion system | |
| CN115102223B (en) | SVG-equipped photovoltaic grid-connected system and control method for loop forming in system | |
| CN103414214B (en) | The low voltage crossing of asynchronous Wind turbines and powerless control system and method | |
| CN105207270B (en) | Improve the inverter power control method for coordinating of grid-connected voltage out-of-limit | |
| CN116937546A (en) | Wind storage grid connection considered power grid low-frequency oscillation suppression method and system | |
| CN113852099B (en) | Rapid frequency response control system and method for direct-driven wind turbine generator | |
| Berboucha et al. | Fuzzy logic control of wind turbine storage system connected to the grid using multilevel inverter | |
| Tiwari et al. | UPQC Controlled Solar PV-Hydro Battery Microgrid | |
| Yang et al. | Harmonic Current Suppression of Grid-Connected PV Based on PR Control Strategy | |
| Zhu et al. | Strategy of reactive power and voltage control in large wind farms integrated region | |
| Mohamed et al. | Enhanced Non-linear PID-Based on Virtual Inertia Control to Enhance the Frequency Stability of a Hybrid Power System | |
| CN115051408A (en) | Photovoltaic grid-connected system with additional damping control and control method | |
| Liu et al. | Terminal Voltage Dynamics Analysis and Stability Assessment of Gird Forming Converters with the Impact of Grid Current Feedforward Control | |
| Abo-Alela | Design and Performance of Hybrid Wind-Solar Energy Generation System for Efficiency Improvement | |
| Alonso-Martinez et al. | Control of a three-phase grid-connected inverter for photovoltaic applications with a fuzzy MPPT under unbalanced conditions | |
| CN110112772B (en) | Energy inversion grid-connected control device and control method | |
| Mughni et al. | Power Quality Improvement of Hybrid System in Grid and Islanded Mode of Operation Using DSTATCOM BESS | |
| Othman | Performance Analysis of Grid Connected and Islanded Modes of AC/DC Microgrid for Residential Home Cluster | |
| Nempu et al. | Mitigation of Power Fluctuations of a Grid-Tied Wind Energy System Using Battery Storage System | |
| Li et al. | Check for updates Coordinated Control Strategy of Secondary Ripple in DC Microgrid Based on Impedance Model | |
| Matewos et al. | Resonance Investigation of Grid Connected DFIG System |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |