CN111711210B - Energy storage system and offshore wind power device suitable for offshore wind power - Google Patents
Energy storage system and offshore wind power device suitable for offshore wind power Download PDFInfo
- Publication number
- CN111711210B CN111711210B CN202010614253.3A CN202010614253A CN111711210B CN 111711210 B CN111711210 B CN 111711210B CN 202010614253 A CN202010614253 A CN 202010614253A CN 111711210 B CN111711210 B CN 111711210B
- Authority
- CN
- China
- Prior art keywords
- energy storage
- wind power
- offshore wind
- alternating current
- bridge
- 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
Images
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
- H02J3/28—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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/01—Arrangements for reducing harmonics or ripples
-
- 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
-
- 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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33584—Bidirectional converters
-
- 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
- H02J2300/28—The renewable source being wind energy
-
- 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
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
-
- 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
- Y02E40/40—Arrangements for reducing harmonics
-
- 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
Abstract
The embodiment of the invention relates to an energy storage system suitable for offshore wind power and an offshore wind power device, wherein the energy storage system suitable for offshore wind power is connected with a three-phase alternating current output line after confluence and boosting of offshore wind power; the series link comprises a second static switch, a current-limiting reactor, an LC filter and a transformer, and the energy storage system suitable for offshore wind power can improve the offshore wind power grid-connected performance through the arranged parallel link, provide active and reactive support and effectively solve the problem of offshore wind power fluctuation; the parameters of the offshore wind power transmission line can be dynamically improved through the arranged series link, the problems of low-frequency and high-frequency resonance and short-circuit current limiting of the offshore wind power are solved, and the technical problems of power fluctuation, low-frequency and high-frequency resonance and short-circuit current limiting of the existing offshore wind power are solved.
Description
Technical Field
The invention relates to the technical field of offshore wind power, in particular to an energy storage system suitable for offshore wind power and an offshore wind power device.
Background
In recent years, the productivity level and the technical innovation capability of a power grid are continuously enhanced, the large-scale development of new energy such as offshore wind power and the like becomes a trend, and new challenges are provided for the safe and stable operation of the power grid.
Offshore wind power has volatility, intermittent type nature, irregularity characteristics, and power oscillation can appear when offshore wind power merges the electric wire netting, and the introduction that currently adopts energy storage system can provide certain buffering for offshore wind power inserts the electric wire netting, plays the effect of smooth scene power output and energy scheduling to can improve new forms of energy generated power unstability to a certain extent, thereby improve electric energy quality, promote the predictability of new forms of energy electricity generation, increase of utilization ratio.
The energy storage system configured by the conventional wind power plant is connected with a high-voltage grade bus (10kV/35kV and the like) through a power frequency transformer, the charging and discharging efficiency is low, the size is large, the energy storage system is connected with the bus in parallel and can be regarded as a PQ (active power and reactive power) power supply, the parallel energy storage system is single in function, the line parameters cannot be improved, the offshore wind power oscillation cannot be inhibited, and the fault current limitation cannot be carried out.
Disclosure of Invention
The embodiment of the invention provides an energy storage system suitable for offshore wind power and an offshore wind power device, which are used for solving the technical problems of power fluctuation, low-frequency and high-frequency resonance and short-circuit current limiting of the existing offshore wind power.
In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:
an energy storage system suitable for offshore wind power is connected with a three-phase alternating current output line after confluence and boosting of the offshore wind power, and comprises a parallel link and a series link connected with the parallel link;
the parallel link comprises an alternating current and energy storage module and a first static switch connected with the alternating current and energy storage module, and the alternating current and energy storage module comprises a plurality of alternating current and energy storage sub-modules;
the series link comprises a second static switch, a current-limiting reactor, an LC filter and a transformer, the second static switch is connected with the current-limiting reactor in series and then connected with the LC filter in parallel, and the LC filter is connected with a primary coil of the transformer.
Preferably, each of the alternating current and energy storage sub-modules comprises a bypass mechanical switch, a front-stage H-bridge connected with the bypass mechanical switch, a DC/DC unit connected with the front-stage H-bridge, an energy storage unit connected with the DC/DC unit, and a rear-stage H-bridge connected with the energy storage unit;
the bypass mechanical switch is used for controlling an online bypass of the alternating current and energy storage submodule;
the front-stage H bridge is used for converting high-voltage alternating current into low-voltage direct current;
the DC/DC unit is used for isolating and converting low-voltage direct current;
the energy storage unit is used for storing energy;
the rear-stage H bridge is used for converting low-voltage direct current into low-voltage alternating current.
Preferably, the DC/DC unit is a bidirectional active bridge structure, and the DC/DC unit includes two sets of H-bridges, and a reactor and a high-frequency transformer connected between the two sets of H-bridges.
Preferably, the pre-stage H-bridge and the DC/DC unit include a plurality of MOSFET devices therein.
Preferably, the back-stage H-bridge comprises several IGBT devices.
Preferably, the working modes of the alternating current and energy storage sub-module comprise:
when the alternating current and energy storage submodule normally works, the bypass mechanical switch is switched off, and the front-stage H bridge, the DC/DC unit, the energy storage unit and the rear-stage H bridge normally work;
when the alternating current and energy storage submodule has a fault, the bypass mechanical switch is closed, and the front-stage H bridge, the DC/DC unit, the energy storage unit and the rear-stage H bridge do not work.
Preferably, the energy storage unit comprises several batteries connected in series.
Preferably, the first static switch is connected to the current-limiting reactor and the LC filter, respectively.
Preferably, the working modes of the energy storage system suitable for offshore wind power comprise:
if the offshore wind power works normally, the first static switch is closed, the second static switch is opened, and the current-limiting reactor does not work;
if the offshore wind power is in fault, the first static switch is switched off, the second static switch is switched on, and the current-limiting reactor works.
The invention also provides an offshore wind power device which comprises three-phase alternating current output lines obtained after the convergence and the boosting of the offshore wind power and the energy storage system suitable for the offshore wind power, wherein the three-phase alternating current output lines obtained after the convergence and the boosting of the offshore wind power are connected with the energy storage system suitable for the offshore wind power.
According to the technical scheme, the embodiment of the invention has the following advantages:
1. the energy storage system suitable for offshore wind power can improve the offshore wind power grid-connected performance through the arranged parallel link, provides active and reactive support, and effectively solves the problem of offshore wind power fluctuation; the parameters of the offshore wind power transmission line can be dynamically improved through the arranged series link, the problems of low-frequency and high-frequency resonance and short-circuit current limiting of the offshore wind power are solved, and the technical problems of power fluctuation, low-frequency and high-frequency resonance and short-circuit current limiting of the existing offshore wind power are solved.
2. The offshore wind power grid-connected performance can be improved through a parallel link suitable for the arrangement of an energy storage system of offshore wind power, active and reactive support is provided, and the problem of offshore wind power fluctuation is effectively solved; the parameters of the offshore wind power transmission line can be dynamically improved through the arranged series link, and the problems of low-high frequency resonance and short-circuit current limiting of the offshore wind power are solved, so that the technical problems of power fluctuation, low-high frequency resonance and short-circuit current limiting of the existing offshore wind power are 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, and 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 these drawings without inventive exercise.
Fig. 1 is a frame diagram of an energy storage system suitable for offshore wind power according to an embodiment of the present invention.
Fig. 2 is a frame diagram of an energy storage system ac and energy storage module suitable for offshore wind power according to an embodiment of the present invention.
Fig. 3 is a schematic circuit diagram of an energy conversion and energy storage submodule of the energy storage system suitable for offshore wind power according to the embodiment of the present invention.
Fig. 4a is a schematic diagram of an online bypass of an energy storage system suitable for offshore wind power according to an embodiment of the present invention.
Fig. 4b is another schematic diagram of an online bypass of an energy storage system suitable for offshore wind power according to an embodiment of the present invention.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the embodiments described below 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.
In recent years, the productivity level and the technical innovation capability of a power grid are continuously enhanced, and offshore wind power and other new energy resources are developed and accessed in a large scale, according to the Guangdong offshore wind power development planning (2017-:
firstly, offshore wind power has the characteristics of volatility, intermittence and irregularity, large-scale offshore wind power access has obvious influence on the stability of a receiving-end power grid, and a large-scale fluctuating new energy and complex large power grid interaction influence and stability control technology is not available at present;
secondly, when large-scale offshore wind power is connected to the grid, the random fluctuation characteristic of the wind speed can cause forced power oscillation of the fan, so that the forced power oscillation of the power system is caused, and the introduction of the fan can also change the damping characteristic of the power system to aggravate low-frequency oscillation. In addition, the power transmission line of the power grid has distributed parameters, and the characteristic harmonic current is easy to amplify under the influence of the broadband and higher harmonic current emitted by the wind power converter, so that high-frequency resonance is caused.
And thirdly, the scale of the power grid is rapidly expanded, the interconnection of regional power grids is gradually tightened, the capacity of a transformer of a medium-voltage power grid is increased, and a small-capacity power supply is continuously merged into a large power grid, so that the short-circuit capacity is rapidly increased. Short-circuit faults are very harmful to the normal operation of the power system and to the electrical equipment itself.
Therefore, the embodiment of the application provides an energy storage system and an offshore wind power device suitable for offshore wind power, the offshore wind power grid-connected performance can be improved through the arranged parallel link, active and reactive support is provided, and the problem of offshore wind power fluctuation is effectively solved; the parameters of the offshore wind power transmission line can be dynamically improved through the arranged series link, and the problems of low-frequency and high-frequency resonance and short-circuit current limiting of the offshore wind power are solved; the technical problems of power fluctuation, low-frequency and high-frequency resonance and short-circuit current limiting of the existing offshore wind power are solved.
The first embodiment is as follows:
fig. 1 is a frame diagram of an energy storage system suitable for offshore wind power according to an embodiment of the present invention.
As shown in fig. 1, an embodiment of the present invention provides an energy storage system suitable for offshore wind power, where the energy storage system suitable for offshore wind power is connected to a three-phase ac output line after confluence and boosting of offshore wind power, and the energy storage system suitable for offshore wind power includes a parallel link 10 and a series link 20 connected to the parallel link 10;
the parallel link 10 comprises an alternating current and energy storage module 11 and a first static switch 12 connected with the alternating current and energy storage module 11, wherein the alternating current and energy storage module 11 comprises a plurality of alternating current and energy storage sub-modules;
the series link 20 includes a second static switch 21, a current-limiting reactor 22, an LC filter 23, and a transformer 24, the second static switch 21 is connected in series with the current-limiting reactor 22 and then connected in parallel with the LC filter 23, and the LC filter 23 is connected to a primary coil of the transformer 24.
In the embodiment of the invention, the parallel link 10 can improve the offshore wind power grid-connected performance, provide active and reactive support and effectively solve the problem of offshore wind power fluctuation; the series link 20 can dynamically improve the parameters of the offshore wind power transmission line, and solve the problems of low-frequency and high-frequency resonance and short-circuit current limiting of the offshore wind power.
In this embodiment, the static switch is also called a static switch, which is a contactless switch, and is an ac switch formed by connecting two Silicon Controlled Rectifiers (SCRs) in reverse parallel, and the on and off of the ac switch is controlled by a logic controller.
Fig. 2 is a frame diagram of an energy storage system ac and energy storage module suitable for offshore wind power according to an embodiment of the present invention.
In the embodiment of the present invention, the parallel link 10 mainly includes an ac and energy storage module 11 and a first static switch 12. As shown in fig. 2, the ac and energy storage module includes a plurality of ac and energy storage sub-modules connected in parallel, and the number of the ac and energy storage sub-modules may be increased or decreased according to the voltage level. In this embodiment, the ac and energy storage module includes 13 ac and energy storage sub-modules. In order to enable the energy storage system suitable for offshore wind power to be directly connected to a medium-voltage power grid so as to save heavy power frequency boosting transformer and simultaneously increase the rated power of each converter as much as possible so as to reduce the number of converters used by an energy storage power station, the alternating current and energy storage sub-module of the embodiment of the invention adopts a cascaded H-bridge Converter (CHB) or a Modular Multilevel Converter (MMC). The alternating current and energy storage module 11 is composed of identical alternating current and energy storage sub-modules in a cascade connection mode, and the higher the cascade number is, the higher the level number and rated power of the output voltage of the alternating current and energy storage module 11 are. Therefore, when the number of cascades is large enough, the ac and energy storage module 11 can omit the heavy export boost direct access to the grid, and the rated power of the ac and energy storage module 11 can also reach the level of tens of megawatts.
It should be noted that, the ac and energy storage sub-modules adopt a cascaded H-bridge Converter (CHB) or a Modular Multilevel Converter (MMC), and they have a common characteristic that the difference of battery characteristics is isolated in the form of a module. When the same capacity is realized, the cascade H-bridge converter and the modular multilevel converter are lower than the battery series-parallel connection scale of the two-level converter by one order of magnitude, so that the pressure of battery equalization is greatly reduced while the battery management is refined. On the contrary, under the same battery series-parallel connection scale, the cascaded H-bridge converter and the modular multilevel converter can realize the capacity higher by one order of magnitude than that of the two-level converter, and the modular topology has the power control capability of relatively independently controlling each alternating current and energy storage submodule, so that the batteries with different echelons and different types can be adopted in each alternating current and energy storage submodule. However, a certain circulating current component exists in the modular multilevel converter, and if the battery pack is directly connected to each alternating current and energy storage sub-module and does not inhibit the circulating current, more serious battery heating can be caused, and the service life attenuation is accelerated. The three-phase modular multilevel converter has 6 bridge arms in total, and the energy of each bridge arm and an internal sub-module needs to be balanced and controlled, and three-phase circulation needs to be controlled. When the energy storage system suitable for offshore wind power is applied to building a special high-power large-capacity energy storage power station, the alternating-current and energy storage sub-modules in the embodiment of the invention adopt the cascaded H-bridge converter, and have certain advantages in the aspects of complexity, economy, reliability and the like of a power system. The H-bridge is an electronic circuit that inverts/inverts the voltage across the connected load or output.
In the embodiment of the invention, the alternating current and energy storage module 11 adopts a modular design, is easy to assemble, maintain and expand, so that the energy storage system suitable for offshore wind power can be directly accessed at high voltage, and has high efficiency; the internal high-frequency isolation of the alternating current and energy storage sub-modules enables the energy storage system suitable for offshore wind power to be small in size.
In the embodiment of the present invention, the series link 20 mainly includes a transformer 24, an LC filter 23, a current limiting reactor 22 and a second static switch 21, the transformer 24 is connected in series to a bus at the output end of the three-phase ac output line after the offshore wind power confluence voltage boost, and the current limiting reactor 22 and the second static switch 21 are connected in series and then connected in parallel to the secondary side of the transformer 24 and the LC filter.
The first static switch is connected to the current limiting reactor 22 and the LC filter 23, respectively.
According to the energy storage system suitable for offshore wind power, provided by the invention, the offshore wind power grid-connected performance can be improved through the arranged parallel link, active and reactive support is provided, and the problem of offshore wind power fluctuation is effectively solved; the parameters of the offshore wind power transmission line can be dynamically improved through the arranged series link, the problems of low-frequency and high-frequency resonance and short-circuit current limiting of the offshore wind power are solved, and the technical problems of power fluctuation, low-frequency and high-frequency resonance and short-circuit current limiting of the existing offshore wind power are solved.
Fig. 3 is a schematic circuit diagram of an energy conversion and energy storage submodule of the energy storage system suitable for offshore wind power according to the embodiment of the present invention.
In one embodiment of the present invention, as shown in fig. 3, each ac and energy storage submodule includes a bypass mechanical switch, a front-stage H-bridge connected to the bypass mechanical switch, a DC/DC unit connected to the front-stage H-bridge, an energy storage unit connected to the DC/DC unit, and a rear-stage H-bridge connected to the energy storage unit; the bypass mechanical switch is used for controlling an online bypass of the alternating current and energy storage submodule; the front-stage H bridge is used for converting high-voltage alternating current into low-voltage direct current; the DC/DC unit is used for isolating and converting low-voltage direct current; the energy storage unit is used for storing energy; the rear-stage H bridge is used for converting low-voltage direct current into low-voltage alternating current. The alternating current and energy storage sub-modules adopt cascade H-bridges, the alternating current and energy storage sub-modules adopt a modular design, and the wiring schematic diagram of the alternating current and energy storage sub-modules in the alternating current and energy storage modules is shown in figure 2, so that the bus voltage grade and the voltage resistance and current resistance of devices of the offshore wind power suitable for the connection of the energy storage system of the offshore wind power determine the serial connection of the preceding-stage H-bridges between the two alternating current and energy storage sub-modules, the subsequent-stage H-bridges are connected in parallel, and the energy storage unit is integrated inside.
It should be noted that the preceding stage H-bridge and the DC/DC unit are formed by using a plurality of MOSFET devices, and the preceding stage H-bridge and the DC/DC unit formed by using MOSFET devices can reduce the size because the switching frequency of the preceding stage H-bridge and the DC/DC unit is high. The switching frequency of the rear-stage H bridge is low, and the rear-stage H bridge is formed by a plurality of IGBT devices, so that the cost is saved. The bypass mechanical switch is arranged to realize the online bypass of the alternating current and energy storage submodule; the preceding stage H bridge realizes the conversion from high-voltage alternating current to low-voltage direct current; the DC/DC unit realizes the isolation conversion from low-voltage direct current to low-voltage direct current, wherein a reactor of a high-frequency part realizes soft switching; the energy storage unit is connected between the DC/DC unit and the rear-stage H bridge to store energy; the rear-stage H bridge realizes the conversion from low-voltage direct current to low-voltage alternating current.
In the embodiment of the invention, the DC/DC unit preferably adopts a bidirectional active bridge structure, and comprises two groups of H-bridges, and a reactor and a high-frequency transformer which are positioned between the two groups of H-bridges.
It should be noted that the high-frequency transformer in the DC/DC unit plays a role of high-low voltage electrical isolation, which is beneficial to the selection and design of the energy storage unit, and is easy to realize soft switching, and has less loss when operating at high frequency, thereby improving the operating efficiency of the energy storage system suitable for offshore wind power.
In the embodiment of the invention, the energy storage unit is preferably an energy storage battery, and the energy storage unit is located between the DC/DC unit and the rear-stage H-bridge. As shown in fig. 3, the energy storage unit is composed of several batteries connected in series.
It should be noted that the output voltage of an energy storage battery cell is no more than 4V at most, and the DC voltage required for energy storage generally applied to a power system is between 500-800V. The energy storage system suitable for the offshore wind power realizes high-voltage direct hanging by utilizing a voltage series superposition principle, and a transformer is omitted, so that the energy storage system suitable for the offshore wind power is directly connected into a power grid with 3kV or above voltage level without the transformer, and the voltage matching problem is solved. The high-voltage energy storage system suitable for the offshore wind power is formed by connecting a plurality of batteries in series, and the energy storage system suitable for the offshore wind power and a three-phase alternating current output line of the offshore wind power can be connected, so that three groups of high-voltage energy storage Y with completely consistent structures can be connected to form three-phase high-voltage energy storage. The performance of two single battery cells produced in the same batch cannot be completely consistent even if the two single battery cells are influenced by factors such as manufacturing process errors and use environment differences, so that the method is particularly important for megawatt battery energy storage with large battery output and battery balance control. The traditional megawatt battery energy storage basically adopts a battery passive equalization technology, is influenced by factors such as large number of batteries and large capacity of a single battery core, is difficult to effectively use the battery active equalization technology, and has obvious battery wooden barrel effect. In the embodiment of the invention, the direct-current voltage of the energy storage unit in each alternating-current and energy storage submodule is connected with the power grid of offshore wind power through one DC/DC unit, the front-stage H bridge and the rear-stage H bridge, on one hand, the DC/DC unit can carry out independent charging and discharging control on the battery of the energy storage unit, and the active balance control of the phase inside and the phase between the alternating-current and energy storage submodule is easy to realize. Specifically, the in-phase balance control means that because the alternating current and energy storage sub-modules are in a series structure, the series current of each alternating current and energy storage sub-module is consistent, the voltage can be different, and the total output voltage is balanced in each H bridge, so that the redistribution of the output power can be realized, and the purpose of actively balancing the batteries among the in-phase H bridge modules is achieved; the interphase balance control means that zero sequence voltage components in a safety range can be injected when needed due to the fact that a Y-type connection method is adopted and no zero sequence current path exists, and interphase balance control is achieved by means of extra power of each interphase accessory without influencing the total output power of a power system.
In one embodiment of the invention, the working modes of the alternating current and energy storage sub-modules comprise:
when the alternating current and energy storage submodule normally works, the bypass mechanical switch is switched off, and the front-stage H bridge, the DC/DC unit, the energy storage unit and the rear-stage H bridge normally work;
when the alternating current and energy storage submodule breaks down, the bypass mechanical switch is closed, and the front-stage H bridge, the DC/DC unit, the energy storage unit and the rear-stage H bridge do not work.
Fig. 4a is a schematic diagram of an online bypass of an energy storage system suitable for offshore wind power according to an embodiment of the present invention, and fig. 4b is another schematic diagram of an online bypass of an energy storage system suitable for offshore wind power according to an embodiment of the present invention.
It should be noted that the alternating current and energy storage submodule in the embodiment of the present invention proposes to implement an online bypass of the alternating current and energy storage submodule through the cooperation of a bypass mechanical switch and a MOSFET device in a preceding stage H bridge, and does not need to add a new electronic switch, and the online bypass of the alternating current and energy storage submodule when a fault occurs can provide protection for the energy storage system suitable for the offshore wind power, so as to greatly improve the reliability of the operation of the energy storage system suitable for the offshore wind power. As shown in FIGS. 4a and 4b, when the AC and energy storage sub-module is operating normally, the bypass mechanical switch S is turned on0And (5) disconnecting the H bridge and normally putting the H bridge into operation. When the inside of the alternating current and energy storage sub-module has faults, such as the faults of an energy storage unit, the disconnection faults of power devices (MOSFET devices, IGBT devices and the like) in the H bridge, the power supply faults and the communication faults, the H bridge is immediately sealed, and meanwhile, the bypass mechanical switch S is closed0Input current is diverted to bypass mechanical switch S0And the alternating current and energy storage sub-module exits the operation. When the AC and energy storage sub-module fails, specifically, firstly, the failure of the AC and energy storage sub-module is the failure outside the device, and firstly, the power device S is switched on1、S3Latching the power device S2、S4While bypassing the mechanical switch S0Due to power devices S1、S3The switching-on speed is high, the alternating current and energy storage sub-modules can be temporarily bypassed, the input current route is shown in figure 4a, meanwhile, the fault phase output current and voltage are unchanged by adjusting and controlling, and when a mechanical switch S is bypassed0After closing, the power device S1、S3And (6) locking. If the power device S2、S4Failure of the switch-on/off, first switching on the power device S1、S3Latching the power device S2、S4Simultaneously closing bypass mechanical switch S0Due to power devices S1、S3The switching-on speed is high, the alternating current and energy storage sub-modules can be temporarily bypassed, the input current route is shown in figure 4a, meanwhile, the fault phase output current and voltage are unchanged by adjusting and controlling, and when a mechanical switch S is bypassed0After closing, the power device S1、S3And (6) locking. Third, if the power device S1、S3Failure of the switch-on/off, first switching on the power device S2、S4Latching the power device S1、S3Simultaneously closing bypass mechanical switch S0Due to power devices S2、S4The switching-on speed is high, the alternating current and energy storage sub-modules can be temporarily bypassed, the input current route is shown in figure 4b, meanwhile, the fault phase output current and voltage are unchanged by adjusting and controlling, and when a mechanical switch S is bypassed0After closing, the power device S2、S4And (6) locking.
In the embodiment of the invention, the energy storage system suitable for offshore wind power realizes the online bypass of the alternating current and energy storage sub-modules through the cooperation of the bypass mechanical switch and the preceding stage H bridge, and devices such as IGBT (insulated gate bipolar translator) and the like do not need to be additionally arranged, so that the manufacturing cost of the offshore wind power energy storage device is reduced.
In one embodiment of the invention, the working modes of the energy storage system suitable for offshore wind power comprise:
if the offshore wind power works normally, the first static switch 12 is closed, the second static switch 21 is disconnected, and the current-limiting reactor 22 does not work;
if the offshore wind power is in fault, the first static switch 12 is switched off, the second static switch 21 is switched on, and the current-limiting reactor 22 works.
It should be noted that, when the offshore wind power generation system normally operates, the first static switch 12 is closed, the second static switch 21 is opened, the current limiting reactor 22 exits from operating, at this time, the rear-stage H-bridge operating output voltage of the alternating current and energy storage submodule is filtered by the LC filter 23, a given voltage is formed on the reactor in the DC/DC unit in the alternating current and energy storage submodule, the voltage of the power transmission line of the offshore wind power generation system can be improved, the impedance of the offshore wind power generation system can be adjusted, and the functions of impedance adjustment, high-low frequency resonance suppression, voltage sag control and the like of the offshore wind power generation system can be realized through specific control. When the power transmission line of the offshore wind power has a short-circuit fault, the first static switch 12 is switched off, and the current transformer 24, the current-limiting reactor 22 and the LC filter 23 in the series link 20 are isolated; meanwhile, the second static switch 21 is closed to input the current-limiting reactor 22, and at the moment, the current-limiting reactor 22, the LC filter 23, the transformer 24 and other devices form a passive circuit, the passive circuit is equivalent to a current-limiting impedance, and the current-limiting impedance is equivalently connected in series between an outlet of the offshore wind power and a common connection point of the power transmission line to play a role in limiting current. When the transmission line of the offshore wind power has a fault, instantaneous current impact on the rotor side and the stator side of the offshore wind power can be inhibited, the voltage of the three-phase alternating current output line after the offshore wind power is converged and boosted in the whole fault process is improved, and the rotor is prevented from stalling.
Example two:
as shown in fig. 1, an embodiment of the present invention provides an offshore wind power plant, which includes a three-phase ac output line after confluence and boosting of offshore wind power and the energy storage system suitable for offshore wind power, where the three-phase ac output line after confluence and boosting of offshore wind power is connected to the energy storage system suitable for offshore wind power.
It should be noted that the content of the energy storage system suitable for offshore wind power is elaborated in the first embodiment, and is not described in the second embodiment one by one.
The offshore wind power grid-connected performance can be improved through the parallel link suitable for the arrangement of the energy storage system of the offshore wind power, active and reactive support is provided, and the problem of fluctuation of the offshore wind power is effectively solved; the parameters of the offshore wind power transmission line can be dynamically improved through the arranged series link, and the problems of low-high frequency resonance and short-circuit current limiting of the offshore wind power are solved, so that the technical problems of power fluctuation, low-high frequency resonance and short-circuit current limiting of the existing offshore wind power are solved.
Illustratively, a computer program may be partitioned into one or more modules/units, which are stored in a memory and executed by a processor to accomplish the present application. One or more modules/units may be a series of computer program instruction segments capable of performing certain functions, the instruction segments describing the execution of a computer program in a device.
The device may be a computing device such as a desktop computer, a notebook, a palm top computer, a cloud server, and the like. The device may include, but is not limited to, a processor, a memory. Those skilled in the art will appreciate that the device is not limited and may include more or fewer components than those shown, or some components may be combined, or different components, e.g., the device may also include input output devices, network access devices, buses, etc.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable gate array (FPGA) or other Programmable logic device, discrete gate or transistor logic device, discrete hardware component, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The storage may be an internal storage unit of the computer device, such as a hard disk or a memory of the computer device. The memory may also be an external storage device of the computer device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), etc. provided on the computer device. Further, the memory may also include both internal and external storage units of the computer device. The memory is used for storing computer programs and other programs and data required by the computer device. The memory may also be used to temporarily store data that has been output or is to be output.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, methods and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, systems or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (9)
1. An energy storage system suitable for offshore wind power is connected with a three-phase alternating current output line after confluence and boosting of the offshore wind power and is characterized by comprising a parallel link and a series link connected with the parallel link;
the parallel link comprises an alternating current and energy storage module and a first static switch connected with the alternating current and energy storage module, and the alternating current and energy storage module comprises a plurality of alternating current and energy storage sub-modules;
the series link comprises a second static switch, a current-limiting reactor, an LC filter and a transformer, the second static switch is connected with the current-limiting reactor in series and then connected with the LC filter in parallel, and the LC filter is connected with a primary coil of the transformer;
each alternating current and energy storage submodule comprises a bypass mechanical switch, a front-stage H bridge connected with the bypass mechanical switch, a DC/DC unit connected with the front-stage H bridge, an energy storage unit connected with the DC/DC unit and a rear-stage H bridge connected with the energy storage unit;
the bypass mechanical switch is used for controlling an online bypass of the alternating current and energy storage submodule;
the front-stage H bridge is used for converting high-voltage alternating current into low-voltage direct current;
the DC/DC unit is used for isolating and converting low-voltage direct current;
the energy storage unit is used for storing energy;
the rear-stage H bridge is used for converting low-voltage direct current into low-voltage alternating current.
2. The energy storage system suitable for offshore wind power according to claim 1, wherein the DC/DC unit is a bidirectional active bridge structure, and the DC/DC unit comprises two sets of H-bridges and a reactor and a high frequency transformer connected between the two sets of H-bridges.
3. Energy storage system suitable for offshore wind power according to claim 1, characterized in that said pre-H-bridge and said DC/DC unit comprise several MOSFET devices.
4. Energy storage system suitable for offshore wind power according to claim 1, characterized in that said post stage H-bridge comprises several IGBT devices.
5. The energy storage system suitable for offshore wind power according to claim 1, wherein the working modes of the alternating current and energy storage submodule comprise:
when the alternating current and energy storage submodule normally works, the bypass mechanical switch is switched off, and the front-stage H bridge, the DC/DC unit, the energy storage unit and the rear-stage H bridge normally work;
when the alternating current and energy storage submodule has a fault, the bypass mechanical switch is closed, and the front-stage H bridge, the DC/DC unit, the energy storage unit and the rear-stage H bridge do not work.
6. Energy storage system suitable for offshore wind power according to claim 1, characterized in that said energy storage unit comprises several batteries connected in series.
7. The energy storage system suitable for offshore wind power according to claim 1, wherein the first static switch is connected to the current limiting reactor and the LC filter, respectively.
8. The energy storage system for offshore wind power according to claim 1, wherein the operating mode of the energy storage system for offshore wind power comprises:
if the offshore wind power works normally, the first static switch is closed, the second static switch is opened, and the current-limiting reactor does not work;
if the offshore wind power is in fault, the first static switch is switched off, the second static switch is switched on, and the current-limiting reactor works.
9. An offshore wind power plant, characterized by comprising three-phase alternating current output lines after confluence and boosting of offshore wind power and the energy storage system suitable for offshore wind power as claimed in any one of claims 1 to 8, wherein the three-phase alternating current output lines are connected with the energy storage system suitable for offshore wind power.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010614253.3A CN111711210B (en) | 2020-06-30 | 2020-06-30 | Energy storage system and offshore wind power device suitable for offshore wind power |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010614253.3A CN111711210B (en) | 2020-06-30 | 2020-06-30 | Energy storage system and offshore wind power device suitable for offshore wind power |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111711210A CN111711210A (en) | 2020-09-25 |
| CN111711210B true CN111711210B (en) | 2022-01-25 |
Family
ID=72543854
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010614253.3A Active CN111711210B (en) | 2020-06-30 | 2020-06-30 | Energy storage system and offshore wind power device suitable for offshore wind power |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111711210B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101807799A (en) * | 2010-04-27 | 2010-08-18 | 天津大学 | Super capacitor energy storage type power quality compensator |
| US9960698B2 (en) * | 2014-12-22 | 2018-05-01 | Flex Power Control, Inc. | Reliable AC-DC power converter with high voltage DC link |
| CN207705800U (en) * | 2017-08-28 | 2018-08-07 | 杭州模储科技有限公司 | A kind of system for chain type energy storage for stabilizing ability with power of battery fluctuation |
| CN109888754A (en) * | 2017-12-06 | 2019-06-14 | 陕西秦能电力科技股份有限公司 | A kind of fault current limiter device |
-
2020
- 2020-06-30 CN CN202010614253.3A patent/CN111711210B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101807799A (en) * | 2010-04-27 | 2010-08-18 | 天津大学 | Super capacitor energy storage type power quality compensator |
| US9960698B2 (en) * | 2014-12-22 | 2018-05-01 | Flex Power Control, Inc. | Reliable AC-DC power converter with high voltage DC link |
| CN207705800U (en) * | 2017-08-28 | 2018-08-07 | 杭州模储科技有限公司 | A kind of system for chain type energy storage for stabilizing ability with power of battery fluctuation |
| CN109888754A (en) * | 2017-12-06 | 2019-06-14 | 陕西秦能电力科技股份有限公司 | A kind of fault current limiter device |
Non-Patent Citations (1)
| Title |
|---|
| 基于电池储能的组合级联式功率转换系统研究;苗青;《中国优秀硕士学位论文全文数据库(电子期刊)工程科技Ⅱ辑》;20140615;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111711210A (en) | 2020-09-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR102311485B1 (en) | Chain-type multi-port grid connection interface device and control method | |
| Priya et al. | Modular‐multilevel converter topologies and applications–a review | |
| Khazaei et al. | Review of HVDC control in weak AC grids | |
| CN107887928B (en) | Control method and device of energy storage system | |
| EP2671310A2 (en) | Power electronic converter | |
| CN113030613B (en) | Direct-current transformer complete machine test system and method | |
| Behrouzian et al. | An overview of multilevel converter topologies for grid connected applications | |
| Shu et al. | A back-to-back VSC-HVDC system of Yu-E power transmission lines to improve cross-region capacity | |
| Jin et al. | A superconducting magnetic energy storage based current-type interline dynamic voltage restorer for transient power quality enhancement of composited data center and renewable energy source power system | |
| Liu et al. | A transformerless three-port nonagonal MMC for the grid connection and local consumption of distributed generation | |
| CN108828360B (en) | Factory full load testing method of high-capacity SVG | |
| Abbasi et al. | A novel controller based on single-phase instantaneous pq power theory for a cascaded PWM transformer-less STATCOM for voltage regulation | |
| CN115967088B (en) | Power distribution fault self-healing method and related device of flexible interconnection switch | |
| Xu et al. | Multilevel-converter-based VSC transmission operating under fault AC conditions | |
| CN111711210B (en) | Energy storage system and offshore wind power device suitable for offshore wind power | |
| CN107171270B (en) | Intensive deicing device constant current, constant pressure modularization dynamic passive compensation component | |
| Yu et al. | Multi-terminal energy router and its distributed control strategy in micro-grid community applications | |
| Yousefpoor et al. | Convertible static transmission controller (CSTC) system model validation by controller hardware-in-the-loop-simulation | |
| Sharouni et al. | Superconductor magnetic energy storage system usage for distributed generation: Active/reactive power and voltage controller design in connected and disconnected cases | |
| CN210074787U (en) | High-power converter circuit topological structure for offshore wind power | |
| Badrzadeh | Qualitative performance assessment of semiconductor switching device, converter and generator candidates for 10 MW offshore wind turbine generators | |
| Ranjitha et al. | A Review on Voltage Balancing Solutions in Multilevel Inverters | |
| Dias et al. | Power electronics in the context of renewables, power quality and smart grids | |
| Luo et al. | Review of HVDC systems for enhancing resilience after extreme natural events | |
| Akbari et al. | operation DVR based Modular Multilevel Cascade Converter based on Double-star Chopper-cells (MMCC-DSCC) for Compensation Voltage sag and swell in Power Distribution Grids |
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 |