CN113904363A - Light storage system state switching control device, photovoltaic system and control method - Google Patents

Light storage system state switching control device, photovoltaic system and control method Download PDF

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CN113904363A
CN113904363A CN202111094954.XA CN202111094954A CN113904363A CN 113904363 A CN113904363 A CN 113904363A CN 202111094954 A CN202111094954 A CN 202111094954A CN 113904363 A CN113904363 A CN 113904363A
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switch
module
switch module
storage system
light storage
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CN113904363B (en
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吴金荣
张惠珍
刘世创
黄詹江勇
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Xiamen Kehua Digital Energy Tech Co Ltd
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Kehua Data Co Ltd
Zhangzhou Kehua Electric Technology 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
    • H02J3/38—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
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • 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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  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Photovoltaic Devices (AREA)

Abstract

The invention provides a state switching control device of a light storage system, a photovoltaic system and a control method. The light storage system state switching control device comprises a photovoltaic contact, a power grid contact and a load contact; the control device also comprises a first switch module, a second switch module, a third switch module and a control module; the three switch modules are all controlled by the control module; the first end of the first switch module is connected with the photovoltaic contact and the first end of the second switch module respectively, and the second end of the first switch module is connected with the power grid contact and the first end of the third switch module respectively; the second end of the second switch module is respectively connected with the load contact and the second end of the third switch module; and the control module is used for controlling the second switch module to continuously keep a closed state when the light storage system is switched from grid connection to off-grid connection, and controlling the first switch module to be switched from the closed state to an open state and controlling the third switch module to be switched from the closed state to the open state. The invention can realize the seamless grid connection and disconnection of the photovoltaic grid.

Description

Light storage system state switching control device, photovoltaic system and control method
Technical Field
The invention relates to the technical field of photovoltaics, in particular to a state switching control device of a light storage system, a photovoltaic system and a control method.
Background
Photovoltaic is a new energy source, has the advantages of safety, environmental protection and reproducibility, and is widely applied to various fields. In an off-grid state of an existing light storage system, a photovoltaic polar plate directly supplies power to a load through a conversion circuit, and the power is not directly connected with a power grid. In the existing light storage system, a photovoltaic polar plate is directly connected to a power grid through a conversion circuit in a grid-connected state, electric energy is scheduled and used by the power grid, and the light storage system is not connected with a load.
When the light storage system needs to be switched from a grid-connected state to an off-grid state, the light storage system needs to be disconnected from the power grid, then the light storage system is connected with the load, and the light storage system supplies power to the load. However, the whole process of switching from grid connection to off-grid of the existing optical storage system is time-consuming, and most of the existing optical storage systems cannot meet the corresponding time requirement of switching between grid connection and off-grid.
Disclosure of Invention
The embodiment of the invention provides a state switching control device of a light storage system, a photovoltaic system and a control method, and aims to solve the problems that the whole process of switching from a grid-connected system to an off-grid system is long in time consumption and can not meet corresponding switching time requirements mostly.
In a first aspect, an embodiment of the present invention provides a light storage system state switching control device, including a photovoltaic contact, a grid contact, and a load contact; the photovoltaic contact is used for being connected with the light storage system, the power grid contact is used for being connected with a power grid, and the load contact is used for being connected with a load;
the control device also comprises a first switch module, a second switch module, a third switch module and a control module; the first switch module, the second switch module and the third switch module are all controlled by the control module;
the first end of the first switch module is connected with the photovoltaic contact and the first end of the second switch module respectively, and the second end of the first switch module is connected with the power grid contact and the first end of the third switch module respectively; the second end of the second switch module is respectively connected with the load contact and the second end of the third switch module;
and the control module is used for controlling the second switch module to continuously keep a closed state when the light storage system is switched from grid connection to off-grid connection, and controlling the first switch module to be switched from the closed state to an open state and controlling the third switch module to be switched from the closed state to the open state.
In one possible implementation, the first switching module includes a first switch and a first inductor; the first switch is controlled by the control module;
the first end of the first inductor is connected with the first end of the first switch, and the second end of the first inductor is connected with the second end of the first switch module; the first end of the first switch is connected with the first end of the first switch module.
In one possible implementation, the second switch module includes a second switch and a second inductor; the second switch is controlled by the control module;
the first end of the second inductor is connected with the second end of the second switch, and the second end of the second inductor is connected with the second end of the second switch module; the first end of the second switch is connected with the first end of the second switch module.
In one possible implementation, the third switch module includes a third switch and a fourth switch connected in series; the third switch and the fourth switch are controlled by the control module; the first end of the third switch is connected with the first end of the third switch module; and the second end of the fourth switch is connected with the second end of the third switch module.
In one possible implementation, the control device further comprises a fourth switching module connected between the light storage system and the photovoltaic junction; the fourth switch module is controlled by the control module;
the control module is further used for controlling the fourth switching module to continuously keep a closed state when the light storage system is switched from grid connection to off-grid connection
In one possible implementation, the fourth switching module includes a fifth switch; the fifth switch is controlled by the control module.
In one possible implementation, the first switch, the second switch, the third switch and the fourth switch are all the same relay; the first inductance and the second inductance are the same.
In one possible implementation manner, the impedance calculation formula of the first inductor and the second inductor is:
Figure BDA0003268764220000031
or ,
RL＝(1+2D)RY
wherein ,
Figure BDA0003268764220000032
RLis the impedance of two identical inductors, RYD is the internal resistance of each identical relay, I is the current proportionality coefficientmaxFor maximum current at actual operating temperature, I, of each identical relayyThe rated current of each identical relay under the rated temperature operation is obtained.
In a second aspect, an embodiment of the present invention provides a photovoltaic system, including the light storage system as described above in the first aspect.
In a second aspect, an embodiment of the present invention provides a control method, which is applied to a control module in the light storage system state switching control apparatus according to the first aspect or the control module in the photovoltaic system according to the second aspect, where the control method includes:
when the light storage system is switched from grid connection to off-grid connection, the second switch module is controlled to continuously keep a closed state, and the first switch module is controlled to be switched from the closed state to an open state and the third switch module is controlled to be switched from the closed state to the open state.
The embodiment of the invention provides a state switching control device of a light storage system, which is connected with the light storage system through a photovoltaic contact, a power grid contact is connected with a power grid, and a load contact is connected with a load; the control device also comprises a first switch module, a second switch module, a third switch module and a control module; the first switch module, the second switch module and the third switch module are all controlled by the control module; the first end of the first switch module is connected with the photovoltaic contact and the first end of the second switch module respectively, and the second end of the first switch module is connected with the power grid contact and the first end of the third switch module respectively; the second end of the second switch module is respectively connected with the load contact and the second end of the third switch module; and the control module is used for controlling the second switch module to continuously keep a closed state when the light storage system is switched from grid connection to off-grid connection, and controlling the first switch module to be switched from the closed state to an open state and controlling the third switch module to be switched from the closed state to the open state. The seamless grid-connected switching off-grid of the optical storage system is realized by arranging the closed second switch module, and the reliability and efficiency of the optical storage system can be improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions 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 to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a state switching control device of an optical storage system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of another optical storage system state switching control apparatus according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a switching control device for determining the state of an optical storage system for calculating the inductance impedance according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a third apparatus for controlling switching of optical storage system states according to an embodiment of the present invention.
Detailed Description
In order to make the technical solution better understood by those skilled in the art, the technical solution in the embodiment of the present invention will be clearly described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is a part of the embodiment of the present invention, and not a whole embodiment. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present disclosure without any creative effort shall fall within the protection scope of the present disclosure.
The terms "include" and any other variations in the description and claims of this document and the above-described figures, mean "include but not limited to", and are intended to cover non-exclusive inclusions and not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc. are used to distinguish between different objects and are not used to describe a particular order.
The following detailed description of implementations of the invention refers to the accompanying drawings in which:
referring to fig. 1, a schematic structural diagram of a light storage system state switching control device according to an embodiment of the present invention is shown. As shown in fig. 1, a light storage system state switching control device 10 includes a photovoltaic junction V3, a grid junction V1 and a load junction V2; the photovoltaic junction V3 is used for being connected with the light storage system 20, the power grid junction V1 is used for being connected with the power grid 20, and the load junction V2 is used for being connected with the load 40;
the control apparatus 10 further comprises a first switch module 110, a second switch module 120, a third switch module 130, and a control module 140; the first switch module 110, the second switch module 120 and the third switch module 130 are all controlled by the control module 140;
a first switch module 110, a first end of which is connected to the photovoltaic junction V3 and a first end of the second switch module 130, respectively, and a second end of which is connected to the grid junction V1 and a first end of the third switch module 130, respectively; a second terminal of the second switching module 120 is connected to the load contact V2 and a second terminal of the third switching module 120, respectively;
and the control module 140 is configured to control the second switching module 130 to continue to maintain the closed state when the light storage system 20 is switched from the grid-connected state to the off-grid state, and control the first switching module 110 to be switched from the closed state to the open state and control the third switching module 130 to be switched from the closed state to the open state.
Optionally, referring to fig. 1, in the embodiment of the present invention, when the grid-connected state is achieved, the first switch module 110, the second switch module 120, and the third switch module 130 are all in the closed state, and the power grid 30 supplies power to the load 40 through the grid contact, the third switch module 130, and the load contact V2 in sequence. In practice, the power grid 30 may be equivalent to infinite energy, so that feeding the light storage system 20 to the power grid through the closed first switch module 110 does not affect the stability of the power grid 30, and feeding the light storage system 20 to the load 40 through the closed second switch module 120 does not affect the normal operation of the load 40. When the grid-connected state needs to be switched to the off-grid state, the first switch module 110 and the third switch module 130 are directly switched to the off-grid state from the closed state, the second switch module 120 is kept in the closed state, and the light storage system 20 is powered by the photovoltaic contact V3, the second switch module 120 and the load contact V2 in sequence, so that normal work of the load is guaranteed, and seamless (namely zero millisecond) switching from the grid-connected state to the off-grid state is realized.
Optionally, the light storage system 20 may include a photovoltaic panel, an energy storage unit, and a power conversion circuit, which may include AC/DC and DC/AC conversion circuits.
The photovoltaic contact is used for being connected with the light storage system, the power grid contact is used for being connected with a power grid, and the load contact is used for being connected with a load; the control device also comprises a first switch module, a second switch module, a third switch module and a control module; the first switch module, the second switch module and the third switch module are all controlled by the control module; the first end of the first switch module is connected with the photovoltaic contact and the first end of the second switch module respectively, and the second end of the first switch module is connected with the power grid contact and the first end of the third switch module respectively; the second end of the second switch module is respectively connected with the load contact and the second end of the third switch module; and the control module is used for controlling the second switch module to continuously keep a closed state when the light storage system is switched from grid connection to off-grid connection, and controlling the first switch module to be switched from the closed state to an open state and controlling the third switch module to be switched from the closed state to the open state. The seamless grid-connected switching off-grid of the photovoltaic is realized by arranging the closed second switch module, the reliability and the efficiency of a photovoltaic system can be improved, and the stability of the operation of a power grid is favorably improved.
Referring to fig. 2, a schematic structural diagram of another optical storage system state switching control device according to an embodiment of the present invention is shown. As shown in fig. 2, in some embodiments of the invention, the first switching module 110 includes a first switch RY1 and a first inductor RL 1; the first switch RY1 is controlled by the control module 140;
a first inductor RL1, a first end of which is connected to the second end of the first switch RY1, and a second end of which is connected to the second end of the first switch module 110; a first end of the first switch RY1 is connected to a first end of the first switch module 110.
Optionally, the positions of the first inductor RL1 and the first switch RY1 may be interchanged, and the first switch RY1 may be a switching device such as a relay that can satisfy the requirement of energy exchange between the light storage system 20 and the power grid 30.
Optionally, the first inductor RL1 is close to the grid connection point V1, and the filtering effect is better.
Referring to fig. 2, in some embodiments of the invention, the second switching module 120 includes a second switch RL2 and a second inductor RY 2; the second switch RY2 is controlled by the control module 140;
a second inductor RL2, having a first end connected to the second end of the second switch RY2, and a second end connected to the second end of the second switch module 120; a first end of the second switch RY2 is connected to a first end of the second switch module 120.
Optionally, the positions of the second inductor RL2 and the second switch RY2 may be interchanged, and the second switch RY2 may be a switching device such as a relay that can supply power to the load 40 of the light storage system 20.
Optionally, the second inductor RL2 is close to the load junction V2, and the filtering effect is better.
Referring to fig. 2, in some embodiments of the present invention, the third switching module 130 includes a third switch RY3 and a fourth switch RY4 connected in series; the third switch RY3 and the fourth switch RY4 are both controlled by the control module 140; a first end of the third switch RY3 is connected to a first end of the third switch module 130; a second terminal of the fourth switch RY4 is connected to a second terminal of the third switch module 130.
Alternatively, the positions of the third switch RY3 and the fourth switch RY4 may be interchanged, and both the third switch RY3 and the fourth switch RY4 may be switching devices such as a relay.
Alternatively, if the third switching module can meet the impact of the power supply from the power grid to the load, the third switching module may include only one switch, or the third switching module may include any number of switches.
Referring to fig. 2, in some embodiments of the invention, the control device further comprises a fourth switching module 150 connected between the light storage system 20 and the photovoltaic junction V3; the fourth switching module 150 is controlled by the control module 140;
the control module 140 is further configured to control the fourth switching module 150 to continue to maintain the closed state when the optical storage system is switched from the grid-connected state to the off-grid state.
Optionally, the fourth switch module is in a closed state in a grid-connected state or an off-grid state.
When the photovoltaic is in a grid-connected state, the photovoltaic can exchange energy with the power grid through the fourth switch module and the first switch module, for example, the photovoltaic feeds power to the power grid or the power grid charges the photovoltaic.
When the photovoltaic is in an off-grid state, the photovoltaic can supply power to the load through the fourth switch module and the second switch module, and normal work of the load is guaranteed.
Referring to fig. 2, in some embodiments of the present invention, fourth switching module 150 includes a fifth switch RY 5; the fifth switch RY5 is controlled by the control module 140.
In some embodiments of the invention, the first switch, the second switch, the third switch, and the fourth switch are all the same relay; the first inductance and the second inductance are the same.
For example, referring to fig. 2, the light storage system state switching control device provided by the embodiment of the invention may include a first switch RY1, a second switch RY2, a third switch RY3, a fourth switch RY4, a fifth switch RY5, a first inductor RL1, and a second inductor RL 2.
The seamless switching process of the embodiment of the invention is as follows:
in the grid-connected state, the first switch RY1, the second switch RY2, the third switch RY3, the fourth switch RY4 and the fifth switch RY5 are all in a closed state. At this time, the power grid 30 supplies power to the load 40, and the power supply line 1 is:
grid 30-third switch RY 3-fourth switch RY 4-load 40.
If the light storage system 20 is powered externally (e.g. if power needs to be supplied to the load or the energy stored by the photovoltaic needs to be released), the possible power supply lines may further include:
power supply line 2: the light storage system 20, a fifth switch RY5, a first switch RY1, and the power grid 30;
power supply line 3: light storage system 20-fifth switch RY 5-second switch RY 2-load 40.
If the light storage system 20 needs to be charged (e.g., at night or other situations requiring charging), the possible power supply lines may further include:
power supply line 4: grid 30-first switch RY 1-fifth switch RY 5-light storage system 20.
When the grid-connected state needs to be switched to the off-grid state, the first switch RY1, the third switch RY3 and the fourth switch RY4 are directly switched off, the fifth switch RY5 and the second switch RY1 are kept closed, and only the power supply line 3 exists at the moment, so that power is supplied to the load 40 only through the light storage system 20.
Therefore, the optical storage system state switching control device provided by the embodiment of the invention ensures that each power supply line has at least two switches, so that the model selection cost of a switch device can be reduced, the reliability of the whole switching device can be improved, and the stability of the operation of a power grid is further improved.
Theoretically, seamless grid-connected and off-grid switching between the optical storage system and the power grid can be achieved through five switches, but in the practical application process, the power grid charges an energy storage device in the optical storage system in a grid-connected state, namely the power grid supplies power to a load and the optical storage system at the same time, and current sharing problems can be caused, so that devices and circuits are damaged. The embodiment of the invention is used for current sharing by adding the first inductor RL1 and the second inductor RL2, and simultaneously can also improve the Electromagnetic Compatibility (EMC) performance of a related circuit. Therefore, the selection of the first inductor RL1 and the second inductor RL2 is particularly important.
In some embodiments of the present invention, the impedance of the first inductor and the second inductor is calculated as:
Figure BDA0003268764220000081
or ,
RL＝(1+2D)RY
wherein ,
Figure BDA0003268764220000091
RLis the impedance of two identical inductors, RYD is the internal resistance of each identical relay, I is the current proportionality coefficientmaxFor maximum current at actual operating temperature, I, of each identical relayyThe rated current of each identical relay under the rated temperature operation is obtained.
Optionally, in some embodiments of the present invention, the current scaling factor may be further defined as:
Figure BDA0003268764220000092
where 0.8 is an empirical value set to account for temperature rise margin (leaving a 20% margin) and 2/3 is an empirical value set based on temperature rise and reliability, the current scaling factor can also be used to control loop error.
Referring to fig. 3, a schematic structural diagram of an optical storage system state switching control apparatus for determining inductive impedance calculation according to an embodiment of the present invention is shown.
As shown in fig. 3, the first relay, the second relay, the third relay and the fourth relay are in a closed state, and the internal resistances of all the relays are the same and are RYThe grid 30 charges the light storage system 20, and a first inductor and a second inductor are added to the circuit to eliminate the situation of the current imbalance, which may generate the current imbalance due to the circuit. Assuming that the first inductor and the second inductor have the same impedance, both are RL。
There are two cases of non-uniform flow:
the first condition is as follows: the current value of the power grid 30 from the power grid connection point V1 to the photovoltaic connection point V3 is larger and is represented as (1+ D) I, the current value of the power grid 30 from the power grid connection point V1 to the load connection point V2 is smaller and is represented as (1-D) I, wherein D is a current proportionality coefficient and is between 0 and 1. The voltage at the grid connection V1 is denoted U1The voltage at load junction V2 is denoted as U2The voltage of the photovoltaic junction V3 is denoted as U3。
A first set of equations may be obtained:
Figure BDA0003268764220000093
solving the first set of equations may result in
Figure BDA0003268764220000094
Case two: the current value of the power grid 30 from the power grid connection point V1 to the photovoltaic connection point V3 is smaller and is represented as (1-D) I, the current value of the power grid 30 from the power grid connection point V1 to the load connection point V2 is smaller and is represented as (1+ D) I, wherein D is a current proportionality coefficient and is between 0 and 1. The voltage at the grid connection V1 is denoted U1The voltage at load junction V2 is denoted as U2The voltage of the photovoltaic junction V3 is denoted as U3。
A second set of equations can be derived:
Figure BDA0003268764220000101
solving the second equation set can yield RL＝(1+2D)RY。
Optionally, current sharing and EMC improvement can be achieved by choosing an inductor of appropriate impedance. In practical application, in order to ensure the reliability and convenience of the circuit as high as possible, the devices playing the same role are mostly selected to be of the same type.
For example, the first switch to the fifth switch in the embodiment of the present invention are relays having the same internal resistance, and it is also necessary to select inductors having the same impedance when selecting the inductors. In practical application, in most cases, in order to ensure that a circuit can work normally and meet relevant voltage resistance or impact resistance parameters, a relay is preferably selected, namely the internal resistance of the relay is known. And then selecting a proper inductor according to the internal resistance of the relay, wherein the formula of the inductor is selected according to the formula.
For another example, referring to fig. 4, a schematic structural diagram of a third optical storage system state switching control device provided in the embodiment of the present invention is shown. As shown in fig. 4, the first switch module 110 may include a first relay RY1, a first inductor RL1, and a sixth relay RY6, which are connected in sequence, the second switch module 120 may include a second relay RY2, a second inductor RL2, and a seventh relay RY7, which are connected in sequence, and the third switch module 130 may include a third relay RY3 and a fourth relay RY4, which are connected in sequence.
The embodiment of the invention also provides a photovoltaic system which comprises the photovoltaic light storage system state switching control device.
The embodiment of the present invention further provides a control method, which is applied to a control module in the above-mentioned optical storage system state switching control apparatus and a control module in the above-mentioned photovoltaic system, where the control method may include;
when the light storage system is switched from grid connection to off-grid connection, the second switch module is controlled to continuously keep a closed state, and the first switch module is controlled to be switched from the closed state to an open state and the third switch module is controlled to be switched from the closed state to the open state.
Optionally, in some embodiments of the present invention, the control method may further include:
and when the light storage system is switched from grid connection to off-grid, the fourth switch module is controlled to continuously keep a closed state.
Optionally, in some embodiments of the present invention, the control method may further include:
and when the light storage system is switched from grid connection to off-grid, controlling the fifth switch module to continuously keep a closed state.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; 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 (10)

1. The light storage system state switching control device is characterized by comprising a photovoltaic contact, a power grid contact and a load contact; the photovoltaic contact is used for being connected with a light storage system, the power grid contact is used for being connected with a power grid, and the load contact is used for being connected with a load;
the control device also comprises a first switch module, a second switch module, a third switch module and a control module; the first switch module, the second switch module and the third switch module are all controlled by the control module;
the first end of the first switch module is connected with the photovoltaic contact and the first end of the second switch module respectively, and the second end of the first switch module is connected with the grid contact and the first end of the third switch module respectively; a second end of the second switch module is connected to the load contact and a second end of the third switch module, respectively;
the control module is used for controlling the second switch module to continuously keep a closed state when the light storage system is switched from a grid-connected state to an off-grid state, and controlling the first switch module to be switched from the closed state to an off state and controlling the third switch module to be switched from the closed state to the off state.
2. The optical storage system state switching control apparatus of claim 1, wherein the first switching module comprises a first switch and a first inductor; the first switch is controlled by the control module;
a first end of the first inductor is connected with a second end of the first switch, and a second end of the first inductor is connected with a second end of the first switch module; the first end of the first switch is connected with the first end of the first switch module.
3. The optical storage system state switching control apparatus of claim 1, wherein the second switch module comprises a second switch and a second inductor; the second switch is controlled by the control module;
a first end of the second inductor is connected with a second end of the second switch, and a second end of the second inductor is connected with a second end of the second switch module; the first end of the second switch is connected with the first end of the second switch module.
4. The light storage system state switching control device of claim 1, wherein the third switch module comprises a third switch and a fourth switch connected in series; the third switch and the fourth switch are controlled by the control module; the first end of the third switch is connected with the first end of the third switch module; a second terminal of the fourth switch is connected to a second terminal of the third switch module.
5. A light storage system state switching control device according to any one of claims 1 to 4, characterized in that the control device further comprises a fourth switching module connected between the light storage system and the photovoltaic junction; the fourth switch module is controlled by the control module;
the control module is further used for controlling the fourth switch module to continuously keep a closed state when the light storage system is switched from grid connection to off-grid connection.
6. The optical storage system state switching control apparatus of claim 5, wherein the fourth switching module comprises a fifth switch; the fifth switch is controlled by the control module.
7. The optical storage system state switching control apparatus of claim 6, wherein the first switch, the second switch, the third switch, and the fourth switch are the same relay; the first inductance and the second inductance are the same.
8. The optical storage system state switching control device according to claim 7, wherein the impedance calculation formula of the first inductor and the second inductor is:
Figure FDA0003268764210000021
or ,
RL＝(1+2D)RY
wherein ,
Figure FDA0003268764210000022
RLis the impedance of two identical inductors, RYD is the internal resistance of each identical relay, I is the current proportionality coefficientmaxFor maximum current at actual operating temperature, I, of each identical relayyThe rated current of each identical relay under the rated temperature operation is obtained.
9. A photovoltaic system comprising a light storage system and a light storage system state switching control apparatus according to any one of claims 1 to 8.
10. A control method applied to a control module in the light storage system state switching control device according to any one of claims 1 to 8 or the photovoltaic system according to claim 9, the control method comprising:
when the light storage system is switched from grid connection to off-grid connection, the second switch module is controlled to continuously keep a closed state, the first switch module is controlled to be switched from the closed state to an open state, and the third switch module is controlled to be switched from the closed state to the open state.
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EP2282388A1 (en) * 2009-08-06 2011-02-09 SMA Solar Technology AG Device for feeding in electrical energy of a number of strings of photovoltaic modules in an electricity network
CN107544034A (en) * 2016-06-25 2018-01-05 高信勇 A kind of high-power energy feedback type electronic load
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