CN110994688B - Photovoltaic energy storage grid-connected and off-grid coordination control method and system - Google Patents

Photovoltaic energy storage grid-connected and off-grid coordination control method and system Download PDF

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CN110994688B
CN110994688B CN201911421863.5A CN201911421863A CN110994688B CN 110994688 B CN110994688 B CN 110994688B CN 201911421863 A CN201911421863 A CN 201911421863A CN 110994688 B CN110994688 B CN 110994688B
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signal
grid
phase
controller
power
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CN110994688A (en
Inventor
方创新
李帅轩
刘�英
李杨松
艾澜
刘玉明
郑庭华
张瞳
杜义
黄云虹
朱当
邓翔天
黄云辉
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Hubei Bailianhe Pumped Storage Power Co ltd
State Grid Corp of China SGCC
Wuhan University of Technology WUT
State Grid Xinyuan Co Ltd
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Hubei Bailianhe Pumped Storage Power Co ltd
State Grid Corp of China SGCC
Wuhan University of Technology WUT
State Grid Xinyuan Co Ltd
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    • 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
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • 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
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
    • 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
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers
    • 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
    • Y02E70/00—Other energy conversion or management systems reducing GHG emissions
    • Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention relates to the technical field of power generation, in particular to a photovoltaic energy storage grid-connected and off-grid coordination control method and a system, wherein the system comprises the following components: the grid-connected and off-grid controller is used for processing three-phase voltage signals and frequency signals at a grid-connected point of the photovoltaic energy storage system to form grid-connected and off-grid selection signals; and the DC/AC conversion controller is used for obtaining an energy storage driving signal according to the grid-connected and off-grid selection signal, the three-phase voltage signal, the three-phase current signal and the frequency signal at the grid-connected point of the photovoltaic energy storage system, and the active power signal and the reactive power signal of the power grid, and sending the energy storage driving signal to the photovoltaic energy storage system for control. The invention can solve the problem that the diesel engine is not enough as the emergency power supply of the pumped storage power station.

Description

Photovoltaic energy storage grid-connected and off-grid coordination control method and system
Technical Field
The invention relates to the technical field of power generation, in particular to a photovoltaic energy storage grid-connected and off-grid coordination control method and system.
Background
The pumped storage power station can convert redundant electric energy when the load of a power grid is low into high-value electric energy during the peak period of the power grid, is also suitable for frequency modulation and phase modulation, stabilizes the cycle wave and voltage of a power system, is suitable for emergency and reserve, and plays an important role in the power grid. However, in most domestic pumped storage power stations, the outgoing line design adopts a single loop to access the power grid, and when line faults such as lightning trip or short circuit occur, the power station has no spare line available, which may cause loss of service power supply. Under the extreme condition that the power station is out of contact with the power grid, the emergency power supply for accidents plays a role and continuously and uninterruptedly supplies power to the service power.
At present, domestic operated pumped storage power stations basically adopt diesel generating sets as emergency power supplies for service accidents, but the diesel generating sets as the emergency power supplies have the following problems: 1) off-line power supply; 2) there is a risk of unsuccessful start-up; 3) there is environmental pollution. 4) The later maintenance cost is higher. In contrast, photovoltaic energy storage systems have the following advantages: online power supply; the reliability is high; the control is flexible; clean and pollution-free; low later maintenance cost and the like. Therefore, the photovoltaic energy storage system replaces a diesel engine to serve as a standby power supply for the service power, and is a reasonable choice for improving the reliability and stability of the service power of the pumped storage power station.
Disclosure of Invention
The backup power supply system of the optical energy storage type pumped storage power station and the control method thereof can solve the problem that the diesel engine is insufficient in reliability as an emergency power supply of the pumped storage power station.
On one hand, the photovoltaic energy storage grid-connected and off-grid coordination control method comprises the following steps:
the grid-connected and off-grid controller processes three-phase voltage signals and frequency signals at a grid-connected point of the photovoltaic energy storage system to form grid-connected and off-grid selection signals;
the DC/AC conversion controller obtains an energy storage driving signal according to the grid-connected and off-grid selection signal, the three-phase voltage signal, the three-phase current signal and the frequency signal at the grid-connected point of the photovoltaic energy storage system, and the active power signal and the reactive power signal of the power grid, and sends the energy storage driving signal to the photovoltaic energy storage system for control.
Further, the DC/AC conversion controller includes: the device comprises a synchronous control unit, a first coordinate converter, a second coordinate converter, a voltage and current controller and a pulse width modulator;
the DC/AC conversion controller obtains an energy storage driving signal according to a grid-connected and off-grid selection signal, a three-phase voltage signal, a three-phase current signal and a frequency signal at a grid-connected point of the photovoltaic energy storage system, and an active power signal and a reactive power signal of a power grid, and specifically comprises the following steps:
the synchronous control unit collects a grid-connected and off-grid selection signal, an active power signal and a three-phase voltage signal of a power grid, calculates to generate a first phase signal, and transmits the first phase signal to the first coordinate converter and the second coordinate converter respectively;
the first coordinate converter receives the first phase signal, acquires a three-phase voltage signal and a three-phase current signal, obtains a d-axis voltage signal, a q-axis voltage signal, a d-axis current signal and a q-axis current signal through coordinate conversion, and transmits the signals to the voltage and current controller;
the voltage and current controller obtains a d-axis voltage modulation signal and a q-axis voltage modulation signal according to the d-axis voltage signal, the q-axis voltage signal, the d-axis current signal, the q-axis current signal and a reactive power signal of the power grid, and transmits the d-axis voltage modulation signal and the q-axis voltage modulation signal to the second coordinate converter;
the second coordinate converter performs coordinate conversion on the d-axis voltage modulation signal, the q-axis voltage modulation signal and the first phase signal to obtain a three-phase voltage modulation signal, and transmits the three-phase voltage modulation signal to the pulse width modulator;
and the pulse width modulator calculates and processes the three-phase voltage modulation signal to obtain an energy storage driving signal.
Still further, the synchronization control unit includes: the fourth subtracter, the power synchronous controller, the phase-locked controller and the selector;
the synchronous control unit collects a grid-connected and off-grid selection signal, an active power signal and a three-phase voltage signal of a power grid, and calculates to generate a first phase signal, and the synchronous control unit specifically comprises the following steps:
the photovoltaic system output active power signal and the service load collected by the fourth subtracter are calculated to obtain an active power reference signal, and the active power reference signal is transmitted to the power synchronous controller;
the power synchronization controller collects an active power signal of a power grid, calculates to obtain a first power grid phase signal by combining with an active power reference signal, and transmits the first power grid phase signal to the selector;
the phase-locked controller obtains a second power grid phase signal according to the three-phase voltage signal and transmits the second power grid phase signal to the selector;
the selector selects either the first grid phase signal or the second grid phase signal to generate the first phase signal based on the grid-on and grid-off selection signal.
Still further, the power synchronization controller includes: the fifth subtracter, the first integrator, the second integrator and the adder are used;
the power synchronization controller collects an active power signal of a power grid, calculates to obtain a first power grid phase signal by combining with an active power reference signal, and specifically comprises:
the fifth subtracter acquires an active power signal and an active power reference signal of a power grid, calculates to obtain a subtraction signal and transmits the subtraction signal to the first integrator;
the first integrator processes the subtraction signal to obtain a power grid phase correction signal and transmits the power grid phase correction signal to the adder;
the second integrator processes a given frequency signal to obtain a second phase signal and transmits the second phase signal to the adder;
and the adder calculates the second phase signal and the power grid phase correction signal to obtain a first power grid phase signal.
Still further, the voltage-current controller includes: the controller comprises a first subtractor, a first PI controller, a second subtractor, a second PI controller, a third subtractor, a third PI controller, a sixth subtractor, a fourth PI controller, a seventh subtractor and a fifth PI controller;
the voltage and current controller obtains a d-axis voltage modulation signal and a q-axis voltage modulation signal according to the d-axis voltage signal, the q-axis voltage signal, the d-axis current signal, the q-axis current signal and a reactive power signal of a power grid, and the voltage and current controller specifically comprises:
the first subtracter calculates the collected power grid reactive power signal and the reactive power given signal and transmits an obtained first result signal to the first PI controller;
the first PI controller calculates the received first result signal to obtain a d-axis voltage reference signal;
the second subtracter collects a d-axis voltage reference signal and a d-axis voltage signal and calculates to obtain a signal;
the second PI controller processes the signal to obtain a d-axis current reference signal;
the third subtracter collects a d-axis current reference signal and a d-axis current signal and calculates to obtain a second result signal;
the third PI controller processes the second result signal to obtain a d-axis voltage modulation signal;
the sixth subtracter collects a q-axis voltage signal and a given q-axis voltage reference signal and calculates to obtain a third result signal;
the fourth PI controller processes the third result signal to obtain a q-axis current reference signal;
the seventh subtracter collects a q-axis current signal and a q-axis current reference signal and calculates to obtain a fourth result signal;
and the fifth PI controller processes the fourth result signal to obtain a q-axis voltage modulation signal.
On the other hand, the photovoltaic energy storage grid-connected and off-grid coordination control system provided by the invention comprises:
the grid-connected and off-grid controller is used for processing three-phase voltage signals and frequency signals at a grid-connected point of the photovoltaic energy storage system to form grid-connected and off-grid selection signals;
and the DC/AC conversion controller is used for obtaining an energy storage driving signal according to the grid-connected and off-grid selection signal, the three-phase voltage signal, the three-phase current signal and the frequency signal at the grid-connected point of the photovoltaic energy storage system, and the active power signal and the reactive power signal of the power grid, and sending the energy storage driving signal to the photovoltaic energy storage system for control.
Further, the DC/AC conversion controller includes: the device comprises a synchronous control unit, a first coordinate converter, a second coordinate converter, a voltage and current controller and a pulse width modulator;
the synchronous control unit is used for acquiring a grid-connected and off-grid selection signal, an active power signal and a three-phase voltage signal of a power grid, calculating to generate a first phase signal, and respectively transmitting the first phase signal to the first coordinate converter and the second phase signal to the second coordinate converter;
the first coordinate converter is used for receiving the first phase signal, acquiring a three-phase voltage signal and a three-phase current signal, obtaining a d-axis voltage signal, a q-axis voltage signal, a d-axis current signal and a q-axis current signal through coordinate conversion, and transmitting the signals to the voltage and current controller;
the voltage and current controller is used for obtaining a d-axis voltage modulation signal and a q-axis voltage modulation signal according to the d-axis voltage signal, the q-axis voltage signal, the d-axis current signal, the q-axis current signal and a reactive power signal of a power grid, and transmitting the d-axis voltage modulation signal and the q-axis voltage modulation signal to the second coordinate converter;
the second coordinate converter is used for carrying out coordinate conversion on the d-axis voltage modulation signal, the q-axis voltage modulation signal and the first phase signal to obtain a three-phase voltage modulation signal and transmitting the three-phase voltage modulation signal to the pulse width modulator;
and the pulse width modulator is used for calculating and processing the three-phase voltage modulation signal to obtain an energy storage driving signal.
Further, the synchronization control unit includes: the fourth subtracter, the power synchronous controller, the phase-locked controller and the selector;
the fourth subtracter is used for acquiring an active power signal and an auxiliary power load output by the photovoltaic system, calculating to obtain an active power reference signal and transmitting the active power reference signal to the power synchronous controller;
the power synchronization controller is used for acquiring an active power signal of a power grid, calculating by combining with an active power reference signal to obtain a first power grid phase signal, and transmitting the first power grid phase signal to the selector;
the phase-locked controller is used for obtaining a second power grid phase signal according to the three-phase voltage signal and transmitting the second power grid phase signal to the selector;
the selector is used for selecting the first power grid phase signal or the second power grid phase signal to generate the first phase signal according to the grid-connected and off-grid selection signal.
Still further, the power synchronization controller includes: the fifth subtracter, the first integrator, the second integrator and the adder are used;
the fifth subtracter is used for acquiring an active power signal and an active power reference signal of a power grid, calculating to obtain a subtraction signal and transmitting the subtraction signal to the first integrator;
the first integrator is used for processing the subtraction signal to obtain a power grid phase correction signal and transmitting the power grid phase correction signal to the adder;
the second integrator is used for processing a given frequency signal to obtain a second phase signal and transmitting the second phase signal to the adder;
and the adder is used for calculating the second phase signal and the power grid phase correction signal to obtain a first power grid phase signal.
Still further, the voltage current controller includes: the controller comprises a first subtractor, a first PI controller, a second subtractor, a second PI controller, a third subtractor, a third PI controller, a sixth subtractor, a fourth PI controller, a seventh subtractor and a fifth PI controller;
the first subtractor is used for calculating the collected power grid reactive power signal and the reactive power given signal and transmitting an obtained first result signal to the first PI controller;
the first PI controller is used for calculating the received first result signal to obtain a d-axis voltage reference signal;
the second subtracter is used for acquiring a d-axis voltage reference signal and a d-axis voltage signal and calculating to obtain a signal;
the second PI controller is used for carrying out signal processing to obtain a d-axis current reference signal;
the third subtracter is used for acquiring a d-axis current reference signal and a d-axis current signal and calculating to obtain a second result signal;
the third PI controller is used for processing the second result signal to obtain a d-axis voltage modulation signal;
the sixth subtracter is used for acquiring a q-axis voltage signal and a given q-axis voltage reference signal and calculating to obtain a third result signal;
the fourth PI controller is used for processing the third result signal to obtain a q-axis current reference signal;
the seventh subtracter is used for acquiring a q-axis current signal and a q-axis current reference signal and calculating to obtain a fourth result signal;
and the fifth PI controller is used for processing the fourth result signal to obtain a q-axis voltage modulation signal.
In the invention, a control system and a control method are designed aiming at a photovoltaic energy storage system as a standby power supply system of a pumped storage power station. The energy storage system in the photovoltaic energy storage system can be switched rapidly between two synchronous modes, so that a control strategy for realizing grid-connection and off-grid seamless switching of the photovoltaic energy storage system is realized. Therefore, the problem that the diesel engine is not enough as an emergency power supply of the pumped storage power station in the prior art is effectively solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a DC/AC conversion controller according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a synchronization control unit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a power synchronization controller according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a voltage-current controller according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the photovoltaic energy storage grid-connected and off-grid coordination control system provided by the present invention includes:
and the grid-connected and off-grid controller 3 is used for aiming at three-phase voltage signals at a grid-connected point of the photovoltaic energy storage systemU abc And the frequency signal, process, form and leave the net selection signal 2;
the DC/AC conversion controller 5 is used for selecting a signal 2 according to the grid-connected and off-grid and three-phase voltage signals at the grid-connected point of the photovoltaic energy storage systemU abc Three-phase current signalI abc And the frequency signal, the active power signal P and the reactive power signal Q of the power grid to obtain an energy storage driving signal 1, and the energy storage driving signal 1 is sent to the photovoltaic energy storage system for control.
In this embodiment, the photovoltaic energy storage system is used as a backup power system of the pumped storage power station. The whole pumped storage power station comprises an auxiliary power load 8, a transformer 9, a photovoltaic energy storage system and a photovoltaic energy storage grid-connected and off-grid coordination control system. The photovoltaic energy storage system comprises: a photovoltaic system 7 and an energy storage system; the energy storage system includes: a battery pack 6 and a DC/AC converter 4; the photovoltaic energy storage grid-connected and off-grid coordination control system comprises a grid-connected and off-grid controller 3 and a DC/AC conversion controller 5.
As shown in fig. 2, the DC/AC conversion controller 5 includes: a synchronization control unit 51, a first coordinate transformer 55, a second coordinate transformer 581, a voltage-current controller 56, and a pulse width modulator 582;
the synchronous control unit 51 is used for collecting the grid-connected and off-grid selection signal 2, the active power signal P of the power grid and the three-phase voltage signalU abc Computationally generating a first phase signal 52, which is passed to a first coordinate transformer 55 and a second coordinate transformer 581, respectively;
the first coordinate converter 55 is used for receiving the first phase signal 52 and collecting a three-phase voltage signalU abc And three-phase current signalI abc Obtaining d-axis voltage signal 57, q-axis voltage signal 58, d-axis current signal 59 and q-axis current signal 580 through coordinate transformation, andto the voltage current controller 56;
the voltage-current controller 56 is configured to obtain a d-axis voltage modulation signal 583 and a Q-axis voltage modulation signal 584 according to the d-axis voltage signal 57, the Q-axis voltage signal 58, the d-axis current signal 59, the Q-axis current signal 580 and the reactive power signal Q of the power grid, and transmit the d-axis voltage modulation signal 583 and the Q-axis voltage modulation signal 584 to the second coordinate converter 581;
the second coordinate transformer 581 is configured to perform coordinate transformation on the d-axis voltage modulation signal 583, the q-axis voltage modulation signal 584, and the first phase signal 52 to obtain a three-phase voltage modulation signal 585, and transmit the three-phase voltage modulation signal 585 to the pulse width modulator 582;
the pulse width modulator 582 is configured to calculate and process the three-phase voltage modulation signal 585 to obtain the energy storage driving signal 1.
As shown in fig. 3, the synchronization control unit 51 includes: a fourth subtractor 511, a power synchronization controller 513, a phase lock controller 515, and a selector 518;
the fourth subtractor 511 is configured to collect an active power signal P output by the photovoltaic systempvAnd service electric load PloadAn active power reference signal 512 is obtained through calculation and is transmitted to the power synchronization controller 513;
the power synchronization controller 513 is configured to collect an active power signal P of the power grid, calculate a first power grid phase signal 514 by combining with the active power reference signal 512, and transmit the first power grid phase signal to the selector 518;
the phase-locked controller 515 is used for controlling the phase-locked signal according to the three-phase voltage signalU abc Obtaining a second grid phase signal 516 and transmitting the second grid phase signal to a selector 518;
the selector 518 is configured to select, according to the on-grid and off-grid selection signal 2, either the first grid phase signal 514 or the second grid phase signal 516 to generate the first phase signal 52.
If the grid is running normally, selecting a grid phase signal 516 sent by a phase-locked controller 515; the grid phase information 514 sent by the power synchronization controller 513 is selected if a transient fault occurs in the grid.
As shown in fig. 4, the power synchronization controller 513 includes: a fifth subtractor 5134, a first integrator 5136, a second integrator 5132, and an adder 5138;
the fifth subtractor 5134 is configured to collect an active power signal P and an active power reference signal 512 of the power grid, obtain a subtraction signal 5135 through calculation, and transmit the subtraction signal 5135 to the first integrator 5136;
the first integrator 5136 is configured to process the subtraction signal 5135 to obtain a power grid phase correction signal 5137, and transmit the power grid phase correction signal 5137 to the adder 5138;
the second integrator 5132 is configured to process the given frequency signal 5131 into a second phase signal 5133, and transmit the second phase signal 5133 to the adder 5138;
the adder 5138 is configured to calculate the second phase signal 5133 and the grid phase correction signal 5137 to obtain the first grid phase signal 514.
As shown in fig. 5, the voltage-current controller 56 includes: a first subtractor 562, a first PI controller 564, a second subtractor 566, a second PI controller 568, a third subtractor 5610, a third PI controller 5612, a sixth subtractor 5614, a fourth PI controller 5616, a seventh subtractor 5618, and a fifth PI controller 5620;
the first subtractor 562 is configured to calculate the collected grid reactive power signal Q and the reactive power given signal 561 and transmit an obtained first result signal 563 to the first PI controller 564;
the first PI controller 564 is configured to calculate the received first result signal 563 to obtain a d-axis voltage reference signal 565;
the second subtractor 566 is configured to collect the d-axis voltage reference signal 565 and the d-axis voltage signal 57, and calculate to obtain a signal 567;
the second PI controller 568 is configured to perform processing on the signal 567 to obtain a d-axis current reference signal 569;
the third subtractor 5610 is configured to acquire a d-axis current reference signal 569 and a d-axis current signal 59, and obtain a second result signal 5611 through calculation;
the third PI controller 5612 is configured to process the second result signal 5611 to obtain a d-axis voltage modulation signal 583;
the sixth subtractor 5614 is configured to collect the q-axis voltage signal 58 and a given q-axis voltage reference signal 5613, and calculate to obtain a third result signal 5615;
the fourth PI controller 5616 is configured to process the third result signal 5615 to obtain a q-axis current reference signal 5617;
the seventh subtractor 5618 is configured to collect the q-axis current signal 580 and the q-axis current reference signal 5617, and obtain a fourth result signal 5619 through calculation;
and the fifth PI controller 5620 is configured to process the fourth result signal 5619 to obtain a q-axis voltage modulation signal 584.
The invention selects the signals transmitted by the power synchronization controller 513 and the phase-locked controller 515 through selector processing according to the grid-connected and off-grid control signal 2 given by the grid-connected and off-grid controller 3 by introducing the synchronization control unit 51. By the control method, the original control mode can be optimized, and the stability of the system can be improved. Meanwhile, the photovoltaic energy storage system based on the control method is used for replacing a diesel generator with the emergency power supply of the pumped storage power station, so that the problems of non-online power supply, unsuccessful starting risk, environmental pollution, high later maintenance cost and the like caused by the diesel generator can be solved, and the reliability of the emergency power supply of the pumped storage power station is improved.
The invention also provides a photovoltaic energy storage grid-connected and off-grid coordination control method, and the technical scheme and the achieved technical effect correspond to the photovoltaic energy storage grid-connected and off-grid coordination control system, so that the details are not repeated.
It should be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.
In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. To those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (6)

1. A photovoltaic energy storage grid-connected and off-grid coordination control method is characterized by comprising the following steps:
the grid-connected and off-grid controller (3) processes three-phase voltage signals and frequency signals at grid-connected points of the photovoltaic energy storage system to form grid-connected and off-grid selection signals (2);
the DC/AC conversion controller (5) obtains an energy storage driving signal (1) according to the grid-connected and off-grid selection signal (2), a three-phase voltage signal, a three-phase current signal and a frequency signal at a grid-connected point of the photovoltaic energy storage system, and an active power signal and a reactive power signal of the power grid, and sends the energy storage driving signal (1) to the photovoltaic energy storage system for control;
the DC/AC conversion controller (5) includes: a synchronization control unit (51), a first coordinate transformer (55), a second coordinate transformer (581), a voltage current controller (56) and a pulse width modulator (582);
the DC/AC conversion controller (5) obtains an energy storage driving signal (1) according to a grid-connected and off-grid selection signal (2), a three-phase voltage signal, a three-phase current signal and a frequency signal at a grid-connected point of the photovoltaic energy storage system, and an active power signal and a reactive power signal of a power grid, and specifically comprises the following steps:
the synchronous control unit (51) collects the grid-connected and off-grid selection signal (2), the active power signal and the three-phase voltage signal of the power grid, calculates and generates a first phase signal (52), and transmits the first phase signal and the first phase signal to a first coordinate converter (55) and a second coordinate converter (581);
the first coordinate converter (55) receives the first phase signal (52), collects a three-phase voltage signal and a three-phase current signal, obtains a d-axis voltage signal (57), a q-axis voltage signal (58), a d-axis current signal (59) and a q-axis current signal (580) through coordinate conversion, and transmits the signals to the voltage and current controller (56);
the voltage and current controller (56) obtains a d-axis voltage modulation signal (583) and a q-axis voltage modulation signal (584) according to the d-axis voltage signal (57), the q-axis voltage signal (58), the d-axis current signal (59), the q-axis current signal (580) and a reactive power signal of a power grid, and transmits the d-axis voltage modulation signal and the q-axis voltage modulation signal to a second coordinate converter (581);
the second coordinate converter (581) performs coordinate conversion on the d-axis voltage modulation signal (583), the q-axis voltage modulation signal (584) and the first phase signal (52) to obtain a three-phase voltage modulation signal (585), and transmits the three-phase voltage modulation signal to the pulse width modulator (582);
the pulse width modulator (582) calculates and processes the three-phase voltage modulation signal (585) to obtain an energy storage driving signal (1);
the synchronization control unit (51) includes: a fourth subtractor (511), a power synchronization controller (513), a phase lock controller (515), and a selector (518);
the synchronous control unit (51) collects the grid-connected and off-grid selection signal (2), the active power signal and the three-phase voltage signal of the power grid, and calculates to generate a first phase signal (52), which specifically comprises:
the photovoltaic system output active power signal and the service load collected by the fourth subtracter (511) are calculated to obtain an active power reference signal (512), and the active power reference signal is transmitted to a power synchronous controller (513);
the power synchronization controller (513) collects an active power signal of the power grid, calculates a first power grid phase signal (514) by combining with an active power reference signal (512), and transmits the first power grid phase signal to the selector (518);
the phase-locked controller (515) obtains a second power grid phase signal (516) according to the three-phase voltage signal and transmits the second power grid phase signal to the selector (518);
the selector (518) selects either the first grid phase signal (514) or the second grid phase signal (516) to generate the first phase signal (52) in dependence on the grid-on/off selection signal (2).
2. The photovoltaic energy storage grid-connected and off-grid coordination control method according to claim 1, characterized in that the power synchronization controller (513) comprises: a fifth subtractor (5134), a first integrator (5136), a second integrator (5132), and an adder (5138);
the power synchronization controller (513) collects an active power signal of a power grid, and calculates to obtain a first power grid phase signal (514) by combining with an active power reference signal (512), and the method specifically includes:
the fifth subtracter (5134) collects the active power signal and the active power reference signal (512) of the power grid, obtains a subtraction signal (5135) through calculation, and transmits the subtraction signal to the first integrator (5136);
the first integrator (5136) processes the subtraction signal (5135) to obtain a power grid phase correction signal (5137), and transmits the power grid phase correction signal to the adder (5138);
the second integrator (5132) processes the given frequency signal (5131) to obtain a second phase signal (5133), and transmits the second phase signal to the adder (5138);
the adder (5138) calculates the second phase signal (5133) and the grid phase correction signal (5137) to obtain the first grid phase signal (514).
3. The photovoltaic energy storage grid-connected and off-grid coordinated control method according to claim 1, wherein the voltage-current controller (56) comprises: a first subtractor (562), a first PI controller (564), a second subtractor (566), a second PI controller (568), a third subtractor (5610), a third PI controller (5612), a sixth subtractor (5614), a fourth PI controller (5616), a seventh subtractor (5618), and a fifth PI controller (5620);
the voltage and current controller (56) obtains a d-axis voltage modulation signal (583) and a q-axis voltage modulation signal (584) according to the d-axis voltage signal (57), the q-axis voltage signal (58), the d-axis current signal (59), the q-axis current signal (580) and a reactive power signal of a power grid, and specifically comprises:
the first subtracter (562) calculates the collected power grid reactive power signal and the reactive power given signal (561) and transmits an obtained first result signal (563) to the first PI controller (564);
the first PI controller (564) calculates a d-axis voltage reference signal (565) from the received first result signal (563);
the second subtracter (566) collects a d-axis voltage reference signal (565) and a d-axis voltage signal (57) to calculate to obtain a signal (567);
the second PI controller (568) processes the signal (567) to obtain a d-axis current reference signal (569);
the third subtracter (5610) collects a d-axis current reference signal (569) and a d-axis current signal (59), and a second result signal (5611) is obtained through calculation;
the third PI controller (5612) processes the second result signal (5611) to obtain a d-axis voltage modulation signal (583);
the sixth subtracter (5614) collects a q-axis voltage signal (58) and a given q-axis voltage reference signal (5613), and calculates to obtain a third result signal (5615);
the fourth PI controller (5616) processes the third result signal (5615) to obtain a q-axis current reference signal (5617);
the seventh subtracter (5618) collects a q-axis current signal (580) and a q-axis current reference signal (5617), and a fourth result signal (5619) is obtained through calculation;
the fifth PI controller (5620) processes the fourth result signal (5619) to obtain a q-axis voltage modulation signal (584).
4. A photovoltaic energy storage and off-grid coordination control system is characterized by comprising:
the grid-connected and grid-disconnected controller (3) is used for processing three-phase voltage signals and frequency signals at a grid-connected point of the photovoltaic energy storage system to form a grid-connected and grid-disconnected selection signal (2);
the DC/AC conversion controller (5) is used for obtaining an energy storage driving signal (1) according to the grid-connected and off-grid selection signal (2), a three-phase voltage signal, a three-phase current signal and a frequency signal at a grid-connected point of the photovoltaic energy storage system, and an active power signal and a reactive power signal of the power grid, and sending the energy storage driving signal (1) to the photovoltaic energy storage system for control;
the DC/AC conversion controller (5) includes: a synchronization control unit (51), a first coordinate transformer (55), a second coordinate transformer (581), a voltage current controller (56) and a pulse width modulator (582);
the synchronous control unit (51) is used for acquiring a grid-connected and off-grid selection signal (2), an active power signal and a three-phase voltage signal of a power grid, calculating to generate a first phase signal (52), and respectively transmitting the first phase signal to a first coordinate converter (55) and a second coordinate converter (581);
the first coordinate converter (55) is used for receiving the first phase signal (52), collecting a three-phase voltage signal and a three-phase current signal, obtaining a d-axis voltage signal (57), a q-axis voltage signal (58), a d-axis current signal (59) and a q-axis current signal (580) through coordinate conversion, and transmitting the signals to the voltage and current controller (56);
the voltage and current controller (56) is used for obtaining a d-axis voltage modulation signal (583) and a q-axis voltage modulation signal (584) according to the d-axis voltage signal (57), the q-axis voltage signal (58), the d-axis current signal (59), the q-axis current signal (580) and a reactive power signal of a power grid, and transmitting the d-axis voltage modulation signal and the q-axis voltage modulation signal (584) to the second coordinate converter (581);
the second coordinate converter (581) is used for carrying out coordinate conversion on the d-axis voltage modulation signal (583), the q-axis voltage modulation signal (584) and the first phase signal (52) to obtain a three-phase voltage modulation signal (585) and transmitting the three-phase voltage modulation signal to the pulse width modulator (582);
the pulse width modulator (582) is used for calculating and processing the three-phase voltage modulation signal (585) to obtain an energy storage driving signal (1);
the synchronization control unit (51) includes: a fourth subtractor (511), a power synchronization controller (513), a phase lock controller (515), and a selector (518);
the fourth subtracter (511) is used for acquiring an active power signal and an auxiliary power load output by the photovoltaic system, calculating to obtain an active power reference signal (512), and transmitting the active power reference signal to the power synchronous controller (513);
the power synchronization controller (513) is configured to collect an active power signal of a power grid, calculate a first power grid phase signal (514) by combining with an active power reference signal (512), and transmit the first power grid phase signal to the selector (518);
the phase-locked controller (515) is used for obtaining a second power grid phase signal (516) according to the three-phase voltage signal and transmitting the second power grid phase signal to the selector (518);
the selector (518) is configured to select either the first grid phase signal (514) or the second grid phase signal (516) to generate the first phase signal (52) in dependence on the grid-on/off selection signal (2).
5. The photovoltaic energy storage grid-connected and off-grid coordinated control system according to claim 4, wherein the power synchronization controller (513) comprises: a fifth subtractor (5134), a first integrator (5136), a second integrator (5132), and an adder (5138);
the fifth subtracter (5134) is used for acquiring an active power signal and an active power reference signal (512) of the power grid, obtaining a subtraction signal (5135) through calculation, and transmitting the subtraction signal to the first integrator (5136);
the first integrator (5136) is used for processing the subtraction signal (5135) to obtain a power grid phase correction signal (5137), and transmitting the power grid phase correction signal to the adder (5138);
the second integrator (5132) is used for processing a given frequency signal (5131) into a second phase signal (5133) and transmitting the second phase signal to an adder (5138);
the adder (5138) is used for calculating the second phase signal (5133) and the power grid phase correction signal (5137) to obtain a first power grid phase signal (514).
6. The photovoltaic energy storage grid-connected and off-grid coordinated control system according to claim 4, wherein the voltage-current controller (56) comprises: a first subtractor (562), a first PI controller (564), a second subtractor (566), a second PI controller (568), a third subtractor (5610), a third PI controller (5612), a sixth subtractor (5614), a fourth PI controller (5616), a seventh subtractor (5618), and a fifth PI controller (5620);
the first subtractor (562) is used for calculating the collected power grid reactive power signal and the reactive power given signal (561) and transmitting a first result signal (563) to the first PI controller (564);
the first PI controller (564) is used for calculating the received first result signal (563) to obtain a d-axis voltage reference signal (565);
the second subtracter (566) is used for acquiring a d-axis voltage reference signal (565) and a d-axis voltage signal (57) to calculate to obtain a signal (567);
the second PI controller (568) is used for carrying out over-processing on the signal (567) to obtain a d-axis current reference signal (569);
the third subtracter (5610) is used for acquiring a d-axis current reference signal (569) and a d-axis current signal (59) and obtaining a second result signal (5611) through calculation;
the third PI controller (5612) is used for processing the second result signal (5611) to obtain a d-axis voltage modulation signal (583);
the sixth subtracter (5614) is used for acquiring a q-axis voltage signal (58) and a given q-axis voltage reference signal (5613) and calculating to obtain a third result signal (5615);
the fourth PI controller (5616) is used for processing the third result signal (5615) to obtain a q-axis current reference signal (5617);
the seventh subtracter (5618) is used for acquiring a q-axis current signal (580) and a q-axis current reference signal (5617), and obtaining a fourth result signal (5619) through calculation;
and the fifth PI controller (5620) is used for processing the fourth result signal (5619) to obtain a q-axis voltage modulation signal (584).
CN201911421863.5A 2019-12-31 2019-12-31 Photovoltaic energy storage grid-connected and off-grid coordination control method and system Expired - Fee Related CN110994688B (en)

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