CN110535179B - Direct current combiner box level energy storage system and control method thereof - Google Patents

Direct current combiner box level energy storage system and control method thereof Download PDF

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Publication number
CN110535179B
CN110535179B CN201910860367.3A CN201910860367A CN110535179B CN 110535179 B CN110535179 B CN 110535179B CN 201910860367 A CN201910860367 A CN 201910860367A CN 110535179 B CN110535179 B CN 110535179B
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current
inverter
direct current
power
combiner box
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CN110535179A (en
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胡华友
朱健雍
陈明月
吴云来
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Zhejiang Astronergy New Energy Development Co Ltd
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Zhejiang Astronergy New Energy Development 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
    • H02J3/24—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
    • H02J3/28—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
    • 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)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a direct current combiner box level energy storage system which comprises a direct current combiner box, an inverter, a current control device and a storage battery, wherein the direct current combiner box is used for being connected with a photovoltaic module; a direct current bus in the direct current bus box is connected with the current control device; the storage battery is connected with the current control device; the measurement and control module in the direct current combiner box is in communication connection with the inverter and is used for acquiring the power of the inverter; when the power of the inverter is not less than the first rated power, the measurement and control module controls the current control device to transmit the redundant current exceeding the first rated current in the direct current bus to the storage battery. Under the super join in marriage the state, observe and control the module and can transmit unnecessary electric current to the battery at the direct current side and store to avoid the waste of electric current and can avoid the overheated emergence of appearing derating operation condition of inverter. The invention also provides a control method, which also has the beneficial effects.

Description

Direct current combiner box level energy storage system and control method thereof
Technical Field
The invention relates to the technical field of photovoltaics, in particular to a direct current combiner box level energy storage system and a control method of the direct current combiner box level energy storage system.
Background
At present, with subsidization of policies of a photovoltaic power generation system, the photovoltaic power generation system is required to be optimally designed from various angles, and the system cost is reduced. The direct current side over-distribution is a commonly adopted mode, but the over-distribution can cause partial loss of electric quantity generated by the photovoltaic module, and can cause the occurrence of peak clipping and even high-power derating operation of the inverter under the condition of ideal radiation value, and the loss of the generated energy is equivalent.
Therefore, how to guarantee the electric quantity transmitted by the inverter in the over-distribution state is an urgent problem to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide a direct current combiner box level energy storage system which can ensure the electric quantity transmitted by an inverter in an over-distribution state; the invention also provides a control method of the DC combiner box level energy storage system, which can ensure the electric quantity transmitted by the inverter in an over-distribution state.
In order to solve the technical problem, the invention provides a direct current combiner box level energy storage system, which comprises a direct current combiner box, an inverter, a current control device and a storage battery, wherein the direct current combiner box is connected with a photovoltaic module;
the direct current combiner box is connected with the inverter, a measurement and control module in the direct current combiner box is in communication connection with the current control device, and a direct current bus in the direct current combiner box is connected with the current control device; the storage battery is connected with the current control device;
the measurement and control module is in communication connection with the inverter and is used for acquiring the power of the inverter; when the power of the inverter is not less than the first rated power, the measurement and control module controls the current control device to transmit the redundant current exceeding the first rated current in the direct current bus to the storage battery.
Optionally, the measurement and control module is further configured to:
and when the power of the inverter is smaller than a second rated power, controlling the current control device to transmit the current in the storage battery to the direct current bus.
Optionally, the measurement and control module is specifically configured to:
when detecting that the current running power of the inverter reaches a maximum power inflection point, controlling the current control device to transmit the redundant current exceeding the standard current in the direct current bus to the storage battery; the standard current is the current corresponding to the maximum power of the inverter in the direct current bus.
Optionally, the current control device includes an energy storage converter and a battery management system;
the energy storage converter with observe and control the module all with direct current bus connects, the battery with the energy storage converter is connected, battery management system with the energy storage converter is connected.
Optionally, the battery management system comprises a remote communication module; the remote communication module is used for being in communication connection with a remote background.
Optionally, the dc combiner box further includes a surge protector connected to the dc bus.
Optionally, the dc combiner box further includes a fuse connected to the photovoltaic module.
The invention also provides a control method of the DC combiner box level energy storage system, which is applied to the measurement and control module and comprises the following steps:
acquiring the power of an inverter; the direct current combiner box level energy storage system comprises a direct current combiner box connected with a photovoltaic assembly, the inverter, a current control device and a storage battery; the direct current combiner box is connected with the inverter, a measurement and control module in the direct current combiner box is in communication connection with the current control device, and a direct current bus in the direct current combiner box is connected with the current control device; the storage battery is connected with the current control device; the measurement and control module is in communication connection with the inverter;
when the power of the inverter is not less than the first rated power, the current control device is controlled to transmit the redundant current exceeding the first rated current in the direct current bus to the storage battery.
Optionally, after obtaining the power of the inverter, the method further includes:
and when the power of the inverter is smaller than a second rated power, controlling the current control device to transmit the current in the storage battery to the direct current bus.
Optionally, the controlling the current control device to transmit the surplus current exceeding the first rated current in the dc bus to the battery when the power of the inverter is not less than the first rated power includes:
when detecting that the current running power of the inverter reaches a maximum power inflection point, controlling the current control device to transmit the redundant current exceeding the maximum current in the direct current bus to the storage battery; the maximum current is the current corresponding to the maximum power of the inverter in the direct current bus.
The invention provides a direct current combiner box level energy storage system which comprises a direct current combiner box, an inverter, a current control device and a storage battery, wherein the direct current combiner box is connected with a photovoltaic assembly; a direct current bus in the direct current bus box is connected with the current control device; the storage battery is connected with the current control device; the measurement and control module in the direct current combiner box is in communication connection with the inverter and is used for acquiring the power of the inverter; when the power of the inverter is not less than the first rated power, the measurement and control module controls the current control device to transmit the redundant current exceeding the first rated current in the direct current bus to the storage battery. In an over-distribution state, the measurement and control module can transmit redundant current to the storage battery for storage at the direct current side, so that the waste of the current is avoided, the occurrence of derating operation condition caused by the overheating of the inverter can be avoided, and the electric quantity transmitted by the inverter is ensured; meanwhile, the electric energy is directly stored at the direct current side, so that the loss of multi-stage voltage conversion can be avoided, and the utilization rate of the current generated by the photovoltaic module is improved.
The invention also provides a control method of the DC combiner box level energy storage system, which has the beneficial effects and is not repeated herein.
Drawings
In order to more clearly illustrate the embodiments or technical solutions of the present invention, 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 it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
Fig. 1 is a block diagram of a dc combiner box-level energy storage system according to an embodiment of the present invention;
fig. 2 is a block diagram of a specific dc combiner box-level energy storage system according to an embodiment of the present invention;
fig. 3 is a flowchart of a method for controlling a dc combiner box-level energy storage system according to an embodiment of the present invention.
In the figure: 1. the direct current power supply comprises a direct current combiner box, 11 measurement and control modules, 12 direct current buses, 2 inverters, 3 current control devices, 31 energy storage converters, 32 battery management systems, 4 storage batteries, 5 surge protectors, 6 fuses, 7 Hall elements, 8 circuit breakers and 9 power supply modules.
Detailed Description
The core of the invention is to provide a DC combiner box level energy storage system. In the prior art, when the direct current side in the photovoltaic power generation system is over-matched, although the inverter can be ensured to operate in a full-power state, partial current generated by the photovoltaic module is wasted; meanwhile, the over-matching can cause the inverter to overheat due to overlarge current, and further cause the occurrence of derating operation conditions.
The invention provides a direct current combiner box level energy storage system, which comprises a direct current combiner box, an inverter, a current control device and a storage battery, wherein the direct current combiner box is connected with a photovoltaic assembly; a direct current bus in the direct current bus box is connected with the current control device; the storage battery is connected with the current control device; the measurement and control module in the direct current combiner box is in communication connection with the inverter and is used for acquiring the power of the inverter; when the power of the inverter is not less than the first rated power, the measurement and control module controls the current control device to transmit the redundant current exceeding the first rated current in the direct current bus to the storage battery. In an over-distribution state, the measurement and control module can transmit redundant current to the storage battery for storage at the direct current side, so that the waste of the current is avoided, the occurrence of derating operation condition caused by the overheating of the inverter can be avoided, and the electric quantity transmitted by the inverter is ensured; meanwhile, the electric energy is directly stored at the direct current side, so that the loss of multi-stage voltage conversion can be avoided, and the utilization rate of the current generated by the photovoltaic module is improved.
In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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.
Referring to fig. 1, fig. 1 is a block diagram of a dc combiner box-level energy storage system according to an embodiment of the present invention.
Referring to fig. 1, in an embodiment of the present invention, a dc combiner box level energy storage system may include a dc combiner box 1 for connecting with a photovoltaic module, an inverter 2, a current control device 3, and a storage battery 4; the direct current combiner box 1 is connected with the inverter 2, a measurement and control module 11 in the direct current combiner box 1 is in communication connection with the current control device 3, and a direct current bus 12 in the direct current combiner box 1 is connected with the current control device 3; the storage battery 4 is connected with the current control device 3; the measurement and control module 11 is in communication connection with the inverter 2, and the measurement and control module 11 is used for acquiring the power of the inverter 2; when the power of the inverter 2 is not less than the first rated power, the measurement and control module 11 controls the current control device 3 to transmit the redundant current exceeding the first rated current in the direct current bus 12 to the storage battery 4.
In the using process, the direct current combiner box 1 is directly connected with the photovoltaic module. In the embodiment of the invention, the direct current combiner box 1 at least comprises a measurement and control module 11 and a direct current bus 12, wherein direct current generated by a photovoltaic module is collected into the direct current bus 12 of the direct current combiner box 1 for transmission; the measurement and control module 11 can collect performance parameters of each component and control each component. The specific structure of the dc combiner box 1 will be described in detail in the following embodiments of the invention, and will not be described herein.
The inverter 2 is connected with the dc combiner box 1, and the dc generated by the photovoltaic module enters the inverter 2 through the dc combiner box 1, so as to convert the dc into ac. Generally, the dc combiner box-level energy storage system provided in the embodiment of the present invention further includes an ac power distribution cabinet, the ac power distribution cabinet is connected to the inverter 2, and the ac power converted by the inverter 2 can be transmitted to a power grid through a current power distribution cabinet. For the specific structure of the inverter 2 and the ac power distribution cabinet, reference may be made to the prior art, and details thereof are not repeated herein.
The current control device 3 is connected to a dc bus 12 in the dc combiner box 1, and the storage battery 4 is connected to the current control device 3, that is, the storage battery 4 is connected to the dc bus 12 through the current control device 3, and the current control device 3 can control and manage charging and discharging of the storage battery 4, including controlling the amount of current flowing into the storage battery 4. The detailed structure of the current control device 3 will be described in detail in the following embodiments of the invention, and will not be described herein.
In the embodiment of the present invention, the measurement and control module 11 in the dc combiner box 1 is in communication connection with the current control device 3 and the inverter 2 at the same time, and the measurement and control module 11 can obtain the power of the inverter 2, generally the current power of the inverter 2. When the power of the inverter 2 is not less than the first rated power, that is, when the power of the inverter 2 is large, usually the power of the inverter 2 reaches the maximum power, that is, the inverter 2 runs at full power, the measurement and control module 11 needs to control the current control device 3 to transmit the excess current exceeding the first rated current in the dc bus 12 to the storage battery 4.
The first rated current, that is, the power of the inverter 2 corresponds to the magnitude of the current in the dc bus 12 when the power is at the first rated power. The first rated current corresponds to the magnitude of the current in the dc bus 12 during full power operation of the inverter 2. Specifically, the excess current in the dc bus 12 that exceeds the first rated current is usually wasted in the state where the inverter 2 is in an overload state, and cannot be converted into the current of the ac power by the inverter 2. In the embodiment of the present invention, when the power of the inverter 2 is not less than the first rated power, the measurement and control module 11 may control the current control device 3 to transmit the excess current exceeding the first rated current in the dc bus 12 to the storage battery 4, that is, the storage battery 4 stores the electric energy of the dc power that cannot be converted by the inverter 2.
Specifically, in the embodiment of the present invention, the measurement and control module 11 may be further configured to control the current control device 3 to transmit the current in the storage battery 4 to the dc bus 12 when the power of the inverter 2 is smaller than a second rated power. When the power of the inverter 2 is less than the second rated power, that is, when the power of the inverter 2 is low, in order to increase the operating power of the inverter 2, the measurement and control module 11 may control the current control device 3 to transmit the current stored in the storage battery 4 to the dc bus 12, so as to transmit the current stored in the storage battery 4 to the inverter 2 through the dc bus 12, thereby increasing the operating power of the inverter 2.
In the embodiment of the present invention, the measurement and control module 11, the current control device 3, and the storage battery 4 can transmit the redundant current in the dc bus 12 in the over-distribution state to the storage battery 4 for storage, and when the power of the inverter 2 is low, the current stored in the storage battery 4 can be transmitted to the inverter 2 through the dc bus 12, so as to increase the operating power of the inverter 2.
At this time, the storage battery 4 can be charged in the off-peak time period and discharged in the on-peak time period by the storage battery 4 in combination with the peak-valley price difference of the user power consumption, so that peak-valley arbitrage is realized. In addition, the direct current combiner box-level energy storage system provided by the embodiment of the invention can start the energy storage system when the photovoltaic output is greater than the load power, so that the electric quantity originally transmitted to a power grid is stored, and the electric quantity is discharged after the load is increased, thereby increasing the spontaneous utilization ratio of the electric quantity of a user. Meanwhile, the direct current combiner box-level energy storage system provided by the embodiment of the invention can directly introduce scheduling to a direct current side and can be used as a system support when a power system needs peak shaving operation of a photovoltaic system. Because photovoltaic power generation output is influenced by weather, the power curve is undulant, but above-mentioned direct current collection flow box level energy storage system smooth output curve reduces voltage fluctuation, improves the electric energy quality.
Specifically, in the embodiment of the present invention, in order to ensure that the measurement and control module 11 can accurately guide the redundant current transmitted in the dc bus 12 to the storage battery 4, the measurement and control module 11 may be specifically configured to:
when detecting that the current operating power of the inverter 2 reaches a maximum power inflection point, controlling the current control device 3 to transmit the redundant current exceeding the standard current in the direct current bus 12 to the storage battery 4; the standard current is the current corresponding to the maximum power of the inverter 2 in the direct current bus 12.
When the current operating power of the inverter 2 reaches the maximum power inflection point, which means that the power of the inverter 2 has reached the maximum at this time, the whole photovoltaic power supply system is in an over-distribution state, and redundant current is transmitted in the direct current bus 12 of the direct current combiner box 1. The measurement and control module 11 can control the current control device 3 to transmit the excess current exceeding the standard current to the storage battery 4 for storage, and the excess current is the current corresponding to the maximum power of the inverter 2 in the dc bus 12, i.e. the current which cannot be converted by the inverter 2.
The embodiment of the invention provides a direct current combiner box level energy storage system, which comprises a direct current combiner box 1, an inverter 2, a current control device 3 and a storage battery 4, wherein the direct current combiner box 1 is used for being connected with a photovoltaic module; a direct current bus 12 in the direct current combiner box 1 is connected with the current control device 3; the storage battery 4 is connected with the current control device 3; a measurement and control module 11 in the direct current combiner box 1 is in communication connection with the inverter 2, and the measurement and control module 11 is used for acquiring the power of the inverter 2; when the power of the inverter 2 is not less than the first rated power, the measurement and control module 11 controls the current control device 3 to transmit the redundant current exceeding the first rated current in the direct current bus 12 to the storage battery 4. In the super-distribution state, the measurement and control module 11 can transmit the redundant current to the storage battery 4 at the direct current side for storage, so that the waste of the current is avoided, the occurrence of derating operation condition caused by overheating of the inverter 2 can be avoided, and the electric quantity transmitted by the inverter 2 is ensured; meanwhile, the electric energy is directly stored at the direct current side, so that the loss of multi-stage voltage conversion can be avoided, and the utilization rate of the current generated by the photovoltaic module is improved.
The specific structure of a dc combiner box stage energy storage system provided by the present invention will be described in detail in the following embodiments of the present invention.
Referring to fig. 2, fig. 2 is a block diagram of a dc combiner box-level energy storage system according to an embodiment of the present invention.
The present invention is different from the above-mentioned embodiments, and the embodiments of the present invention further specifically limit the structure of the dc combiner box stage energy storage system on the basis of the above-mentioned embodiments of the present invention. The rest of the contents are already described in detail in the above embodiments of the present invention, and are not described herein again.
Referring to fig. 2, in the embodiment of the present invention, the current control device 3 includes an energy storage converter 31 and a battery management system 32; the energy storage converter 31 with observe and control module 11 all with direct current bus 12 connects, battery 4 with the energy storage converter 31 is connected, battery management system 32 with the energy storage converter 31 is connected.
The energy storage converter 31, namely the PCS, the energy storage converter 31 can control the charging and discharging processes of the storage battery 4. It should be noted that, in the embodiment of the present invention, the energy storage converter 31 is directly connected to the dc bus 12, and the battery 4 is connected to the energy storage converter 31, so that when the energy storage converter 31 transmits current to the battery 4, ac/dc conversion is not required to be performed in the energy storage converter 31, thereby reducing the loss of current when the current passes through the PCS.
In the embodiment of the present invention, the energy storage converter 31 is in communication connection with the measurement and control module 11 through the dc bus 12, when the measurement and control module 11 controls the current control device 3 to transmit the excess current exceeding the first rated current in the dc bus 12 to the storage battery 4, and the measurement and control module 11 controls the current control device 3 to transmit the current in the storage battery 4 to the dc bus 12, the energy storage converter 31 is generally specifically controlled to transmit the excess current exceeding the first rated current in the dc bus 12 to the storage battery 4, and the measurement and control module 11 is generally specifically controlled to transmit the current in the storage battery 4 to the dc bus 12 by the energy storage converter 31.
The BMS, which is the battery management system 32, is a system for managing the battery, and generally has a function of measuring the voltage of the battery 4, thereby preventing or avoiding abnormal situations such as overdischarge, overcharge, and over-temperature of the battery 4. In the embodiment of the present invention, the battery management system 32 is connected to the storage battery 4 through the energy storage converter 31, and the battery management system 32 manages the battery through the energy storage converter 31. For the specific structure of the battery management system 32, reference may be made to the prior art, and details thereof will not be described herein. Specifically, in the present embodiment, the battery management system 32 generally includes a remote communication module; the remote communication module is used for being in communication connection with a remote background. That is, the battery management system 32 may be generally connected to a remote background, and the remote background may detect and manage the storage battery 4 through the battery management system 32.
In the embodiment of the present invention, the dc combiner box 1 may further include a surge protector 5 connected to the dc bus 12. The surge protector 5 is also called a lightning protector, and in the embodiment of the invention, the surge protector 5 connected with the direct current bus 12 is arranged, so that when peak current or voltage is suddenly generated in the direct current bus 12 due to external interference, the surge protector 5 can conduct and shunt in a very short time, thereby avoiding damage of surge to other equipment in a loop.
In the embodiment of the present invention, the dc combiner box 1 may further include a fuse 6 connected to the photovoltaic module. The fuse 6 is an electric appliance which fuses a fuse element by heat generated by itself to open a circuit when a current exceeds a predetermined value. The fuse 6 connected with the photovoltaic module is arranged in the embodiment of the invention, so that when the current input into the direct current combiner box 1 by the photovoltaic module is suddenly increased, all parts in the direct current combiner box 1 can be protected from being damaged.
In the embodiment of the present invention, the dc combiner box 1 further typically includes a hall element 7, a power module 9, and a circuit breaker 8, where the hall element 7 is typically connected between the photovoltaic module and the dc bus 12 to detect the electromotive force in the circuit. The breaker 8 is connected to a dc bus 12, and the inverter 2 is specifically connected to the dc bus 12 via the breaker 8. The power module 9 is connected with the circuit breaker 8, and the measurement and control module 11 controls the on-off of the circuit breaker 8 through the power module 9 so as to control the output of the current in the direct current combiner box 1. As for the specific structures of the hall element 7, the power module 9 and the circuit breaker 8, reference may be made to the prior art, and detailed description thereof is omitted here.
According to the direct current combiner box-level energy storage system provided by the embodiment of the invention, the energy storage converter 31 and the battery management system 32 are used as the current control device 3, so that the magnitude of output current in the storage battery 4 of the box can be effectively controlled; the use safety of the direct current combiner box 1 can be effectively protected by arranging the surge protector 5 and the fuse 6.
The following describes a method for controlling a dc combiner box-level energy storage system according to an embodiment of the present invention, and the control method described below and the dc combiner box-level energy storage system described above may be referred to in correspondence.
Referring to fig. 3, fig. 3 is a flowchart of a method for controlling a dc combiner box-level energy storage system according to an embodiment of the present invention.
In the embodiment of the present invention, the control method is specifically applied to the measurement and control module 11 in the dc combiner box 1, and the measurement and control module 11 controls the magnitude of the current in the dc bus 12 in the dc combiner box 1 through the current control device 3.
Referring to fig. 3, in an embodiment of the present invention, the control method may include:
s101: and acquiring the power of the inverter.
In the embodiment of the invention, the direct current combiner box level energy storage system comprises a direct current combiner box 1 connected with a photovoltaic module, the inverter 2, a current control device 3 and a storage battery 4; the direct current combiner box 1 is connected with the inverter 2, a measurement and control module 11 in the direct current combiner box 1 is in communication connection with the current control device 3, and a direct current bus 12 in the direct current combiner box 1 is connected with the current control device 3; the storage battery 4 is connected with the current control device 3; and the measurement and control module 11 is in communication connection with the inverter 2. The specific structure of the dc combiner box stage energy storage system has been described in detail in the above embodiments of the invention, and will not be described herein again.
In this step, the measurement and control module 11 obtains the power value of the inverter 2, generally the current power of the inverter 2, so as to determine the state of the inverter 2.
S102: when the power of the inverter is not less than the first rated power, the current control device is controlled to transmit the redundant current exceeding the first rated current in the direct current bus to the storage battery.
In this step, when the power of the inverter 2 is not less than the first rated power, it means that the power of the inverter 2 is large, and usually the power of the inverter 2 reaches the maximum power, that is, the inverter 2 runs at full power. The first rated current, i.e., the power of the inverter 2 corresponds to the magnitude of the current in the dc bus 12 when the power is at the first rated power. The first rated current corresponds to the magnitude of the current in the dc bus 12 during full power operation of the inverter 2. Specifically, the excess current in the dc bus 12 that exceeds the first rated current is usually wasted in the state where the inverter 2 is in an overload state, and cannot be converted into the current of the ac power by the inverter 2. In this step, when the power of the inverter 2 is not less than the first rated power, the current control device 3 is controlled to transmit the excess current in the dc bus 12, which exceeds the first rated current, to the storage battery 4, that is, the storage battery 4 stores the electric energy of the dc power that cannot be converted by the inverter 2.
Specifically, the step may specifically be:
when detecting that the current operating power of the inverter 2 reaches a maximum power inflection point, controlling the current control device 3 to transmit the redundant current exceeding the standard current in the direct current bus 12 to the storage battery 4; the standard current is the current corresponding to the maximum power of the inverter 2 in the direct current bus 12.
When the current operating power of the inverter 2 reaches the maximum power inflection point, which means that the power of the inverter 2 has reached the maximum at this time, the whole photovoltaic power supply system is in an over-distribution state, and redundant current is transmitted in the direct current bus 12 of the direct current combiner box 1. At this time, the measurement and control module 11 may control the current control device 3 to transmit the excess current exceeding the standard current to the storage battery 4 for storage, and since the standard current is the current corresponding to the maximum power of the inverter 2 in the dc bus 12, the excess current is the current that cannot be converted by the inverter 2.
S103: and when the power of the inverter is less than the second rated power, controlling the current control device to transmit the current in the storage battery to the direct current bus.
When the power of the inverter 2 is less than the second rated power, that is, when the power of the inverter 2 is low, in order to increase the operating power of the inverter 2, in this step, the measurement and control module 11 may control the current control device 3 to transmit the current stored in the storage battery 4 to the dc bus 12, so as to transmit the current stored in the storage battery 4 to the inverter 2 through the dc bus 12, thereby increasing the operating power of the inverter 2.
It should be noted that step S103 is not necessarily required to be performed in the embodiment of the present invention, that is, in the embodiment of the present invention, only by step S101 and step S102, it is possible to avoid waste of current and occurrence of derating operation condition due to overheating of the inverter 2, so as to ensure the amount of power transmitted by the inverter 2. After the step S103 is provided, the functions of increasing the operating power of the inverter 2, realizing peak-valley arbitrage, increasing the proportion of the self-use of the electric quantity of the user, and the like can be further realized, so as to optimize the use of the dc combiner box level energy storage system. In the embodiment of the present invention, the above-mentioned S103 and S102 do not have a sequence, and the triggering needs to be performed according to different conditions, that is, the operation state of the inverter 2.
According to the control method of the DC combiner box level energy storage system provided by the embodiment of the invention, in an over-distribution state, the measurement and control module 11 can transmit redundant current to the storage battery 4 at a DC side for storage, so that the waste of the current is avoided, the occurrence of derating operation condition caused by overheating of the inverter 2 can be avoided, and the electric quantity transmitted by the inverter 2 is ensured; meanwhile, the electric energy is directly stored at the direct current side, so that the loss of multi-stage voltage conversion can be avoided, and the utilization rate of the current generated by the photovoltaic module is improved.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The dc combiner box-level energy storage system and the control method of the dc combiner box-level energy storage system according to the present invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (6)

1. A direct current combiner box level energy storage system is characterized by comprising a direct current combiner box, an inverter, a current control device and a storage battery, wherein the direct current combiner box is used for being connected with a photovoltaic module;
the direct current combiner box is connected with the inverter, a measurement and control module in the direct current combiner box is in communication connection with the current control device, and a direct current bus in the direct current combiner box is connected with the current control device; the storage battery is connected with the current control device;
the measurement and control module is in communication connection with the inverter and is used for acquiring the power of the inverter; when the power of the inverter is not less than a first rated power, the measurement and control module controls the current control device to transmit redundant current exceeding the first rated current in the direct current bus to the storage battery;
the measurement and control module is also used for:
when the power of the inverter is smaller than a second rated power, controlling the current control device to transmit the current in the storage battery to the direct current bus;
the measurement and control module is specifically used for:
when detecting that the current running power of the inverter reaches a maximum power inflection point, controlling the current control device to transmit the redundant current exceeding the standard current in the direct current bus to the storage battery; the standard current is the current corresponding to the maximum power of the inverter in the direct current bus.
2. The dc combiner box level energy storage system of claim 1, wherein the current control device comprises an energy storage converter and a battery management system;
the energy storage converter with observe and control the module all with direct current bus connects, the battery with the energy storage converter is connected, battery management system with the energy storage converter is connected.
3. The dc combiner box level energy storage system of claim 2, wherein the battery management system comprises a telecommunications module; the remote communication module is used for being in communication connection with a remote background.
4. The dc combiner box stage energy storage system of claim 1, wherein the dc combiner box further comprises a surge protector connected to the dc bus.
5. The dc combiner box level energy storage system of claim 1, further comprising a fuse connected to a photovoltaic module.
6. A control method of a DC combiner box level energy storage system is applied to a measurement and control module and is characterized by comprising the following steps:
acquiring the power of an inverter; the direct current combiner box level energy storage system comprises a direct current combiner box connected with a photovoltaic assembly, the inverter, a current control device and a storage battery; the direct current combiner box is connected with the inverter, a measurement and control module in the direct current combiner box is in communication connection with the current control device, and a direct current bus in the direct current combiner box is connected with the current control device; the storage battery is connected with the current control device; the measurement and control module is in communication connection with the inverter;
when the power of the inverter is not less than a first rated power, controlling the current control device to transmit redundant current exceeding the first rated current in the direct current bus to the storage battery;
after obtaining power for the inverter, the method further comprises:
when the power of the inverter is smaller than a second rated power, controlling the current control device to transmit the current in the storage battery to the direct current bus;
the controlling the current control device to transmit the surplus current exceeding the first rated current in the direct current bus to the storage battery when the power of the inverter is not less than the first rated power includes:
when detecting that the current running power of the inverter reaches a maximum power inflection point, controlling the current control device to transmit the redundant current exceeding the maximum current in the direct current bus to the storage battery; the maximum current is the current corresponding to the maximum power of the inverter in the direct current bus.
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