CN112886640A - Current limiting circuit and energy storage system - Google Patents

Current limiting circuit and energy storage system Download PDF

Info

Publication number
CN112886640A
CN112886640A CN202110250659.2A CN202110250659A CN112886640A CN 112886640 A CN112886640 A CN 112886640A CN 202110250659 A CN202110250659 A CN 202110250659A CN 112886640 A CN112886640 A CN 112886640A
Authority
CN
China
Prior art keywords
circuit
energy storage
switch
current
voltage
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.)
Pending
Application number
CN202110250659.2A
Other languages
Chinese (zh)
Inventor
曾云洪
李伟进
那科
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gree Electric Appliances Inc of Zhuhai
Original Assignee
Gree Electric Appliances Inc of Zhuhai
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Gree Electric Appliances Inc of Zhuhai filed Critical Gree Electric Appliances Inc of Zhuhai
Priority to CN202110250659.2A priority Critical patent/CN112886640A/en
Publication of CN112886640A publication Critical patent/CN112886640A/en
Pending legal-status Critical Current

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
    • H02J3/38—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
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
    • 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
    • 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
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The application relates to a current limiting circuit and an energy storage system, wherein the current limiting circuit comprises a first detection unit, a second detection unit, a processor, a first switch circuit and a current limiting unit; the first detection unit is connected with the energy storage circuit, and the second detection unit is connected with the power grid; the processor is connected with the first detection unit, the second detection unit and the first switch circuit; the first switch circuit is connected with the first output end of the energy storage circuit and the first end of the power grid; the current limiting unit is connected with the first output end of the energy storage circuit and the first end of the power grid. The first detection unit is used for acquiring a first voltage output by the energy storage circuit; the second detection unit is used for collecting a second voltage output by the power grid. The processor is used for obtaining the first voltage and the second voltage, and outputting a control signal to control the first switch circuit to be switched off when the first voltage is smaller than the second voltage, so that the instantaneous impact current in an off-grid switching and grid-connection state can be reduced, and the use safety of the energy storage system is improved.

Description

Current limiting circuit and energy storage system
Technical Field
The present application relates to the field of energy storage technologies, and in particular, to a current limiting circuit and an energy storage system.
Background
The energy storage system is connected to the grid in a separated mode, so that the energy storage system can realize alternating current and direct current switching between an energy storage power supply and a power grid, and the effect of 'never power off' is realized. The grid connection refers to the connection of power utilization or power generation equipment with a power grid, and the power utilization or power generation equipment absorbs electric energy of the power grid or generates power to the power grid. Off-grid means that the electricity or power generation equipment is not connected with the power grid and is powered by the energy storage power supply.
When the traditional energy storage system is switched off and connected to the grid, due to the access of the power grid, a large instantaneous impact current can be formed between the energy storage power supply and the power grid, the service life of the energy storage system can be seriously influenced, and even the explosion of the energy storage power supply can be possibly caused to cause fire. Therefore, the traditional energy storage system has the defect of poor use safety.
Disclosure of Invention
Therefore, it is necessary to provide a current limiting circuit and an energy storage system capable of reducing instantaneous impact current during off-grid and grid-connected switching to solve the problem of poor use safety of the conventional energy storage system, so that the use safety of the energy storage system is improved.
A current limiting circuit comprises a first detection unit, a second detection unit, a processor, a first switch circuit and a current limiting unit;
the first detection unit is connected with the energy storage circuit, and the second detection unit is connected with the power grid; the processor is connected with the first detection unit, the second detection unit and the first switch circuit; the first switch circuit is connected with a first output end of the energy storage circuit and a first end of the power grid; the current limiting unit is connected with a first output end of the energy storage circuit and a first end of the power grid;
the first detection unit is used for collecting a first voltage output by the energy storage circuit; the second detection unit is used for collecting a second voltage output by the power grid; the processor is used for obtaining the first voltage and the second voltage and outputting a control signal to control the first switch circuit to be switched off when the first voltage is smaller than the second voltage.
In one embodiment, the power supply further comprises a second switch circuit, wherein the second switch circuit is connected with the second output end of the energy storage circuit, the processor and the second end of the power grid;
the first detection unit is also used for collecting a first current output by the energy storage circuit; the second detection unit is also used for collecting a second current output by the power grid; the processor is further configured to obtain the first current and the second current, and output a control signal to control the first switch circuit and the second switch circuit to be turned off when the first current and/or the second current is greater than or equal to a preset current threshold.
In one embodiment, the first switch circuit comprises a first driving unit and a first switch unit, the first driving unit is connected with the control end of the first switch unit and the processor, a first contact of the first switch unit is connected with the first output end of the energy storage circuit, and a second contact of the first switch unit is connected with the first end of the power grid;
the second switch circuit comprises a second driving unit and a second switch unit, the second driving unit is connected with the control end of the second switch unit and the processor, the first contact of the second switch unit is connected with the second output end of the energy storage circuit, and the second contact of the second switch unit is connected with the second end of the power grid.
In one embodiment, the first switch unit and the second switch unit are both controllable dc contactors.
In one embodiment, the current limiting unit is a current limiting resistor.
In one embodiment, the processor is further configured to output a control signal to control the first switch circuit to turn off when the first voltage is greater than the second voltage and a difference between the first voltage and the second voltage is greater than a preset voltage threshold.
An energy storage system comprises an energy storage circuit and the current limiting circuit, wherein the energy storage circuit is connected with the current limiting circuit.
In one embodiment, the energy storage circuit comprises an energy storage power supply, a conversion circuit and an output voltage stabilizing circuit, the conversion circuit is connected with the energy storage power supply and the output voltage stabilizing circuit, and the output voltage stabilizing circuit is connected with the current limiting circuit.
In one embodiment, the conversion circuit is a boost circuit.
In one embodiment, the boost circuit comprises a first inductor, a second inductor, a first switching component, a second switching component, a third switching component and a fourth switching component;
the control ends of the first switch assembly, the second switch assembly, the third switch assembly and the fourth switch assembly are all connected with a main controller;
the first end of the first inductor is connected with the anode of the energy storage power supply, the second end of the first inductor is connected with the first end of the first switch component and the first end of the third switch component, and the second end of the first switch component is connected with the current limiting circuit; the second end of the third switch component is connected with the negative electrode of the energy storage power supply and the current limiting circuit;
the first end of the second inductor is connected with the anode of the energy storage power supply, the second end of the second inductor is connected with the first end of the second switch component and the first end of the fourth switch component, and the second end of the second switch component is connected with the current limiting circuit; and the second end of the fourth switch component is connected with the negative electrode of the energy storage power supply and the current limiting circuit.
In one embodiment, the energy storage circuit further comprises an input voltage stabilizing circuit, and the input voltage stabilizing circuit is connected with the energy storage power supply and the conversion circuit.
The current limiting circuit comprises a processor, a first switch circuit, a first detection unit, a second detection unit and a current limiting unit, wherein the off-grid switching and grid connection are realized, namely when the first voltage output by the energy storage circuit is smaller than the second voltage output by the power grid, the processor outputs a control signal to control the first switch circuit to be disconnected, so that the current limiting unit is connected to the circuit, the potential difference between the power grid and the energy storage circuit can be consumed, the instantaneous impact current is reduced, and the use safety of the energy storage system is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a block diagram of a current limiting circuit according to an embodiment;
FIG. 2 is a block diagram of a current limiting circuit in another embodiment;
FIG. 3 is a block diagram of an embodiment of an energy storage system;
FIG. 4 is a block diagram of a tank circuit according to an embodiment;
FIG. 5 is a schematic diagram of a tank circuit configuration in one embodiment;
fig. 6 is a schematic diagram of an energy storage system in an embodiment.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments is understood to mean "electrical connection", "communication connection", or the like, if there is a transfer of electrical signals or data between the connected objects.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
In one embodiment, as shown in fig. 1, there is provided a current limiting circuit including a first detecting unit 110, a second detecting unit 120, a processor 130, a first switching circuit 140, and a current limiting unit 150. The first detection unit 110 is connected with the energy storage circuit, and the second detection unit 120 is connected with the power grid; the processor 130 is connected to the first detecting unit 110, the second detecting unit 120 and the first switch circuit 140; the first switch circuit 140 is connected to the first output terminal of the tank circuit and the first terminal of the grid; the current limiting unit 150 is connected to the first output of the tank circuit and the first end of the grid. The first detection unit 110 is configured to collect a first voltage output by the tank circuit; the second detection unit 120 is configured to collect a second voltage output by the power grid; the processor 130 is configured to obtain the first voltage and the second voltage, and output a control signal to control the first switch circuit 140 to turn off when the first voltage is less than the second voltage.
The first detecting unit 110 and the second detecting unit 120 may be a circuit unit that includes a transformer and performs voltage detection based on an induction principle, or may be a circuit unit that includes a voltage dividing or shunting device and performs voltage detection based on a voltage dividing or shunting principle. The processor 130 may be a control chip or a control circuit including a logic device. The first switching circuit 140 is a circuit unit including a switching device, which may be a transistor or a relay. The current limiting unit 150 is a circuit unit having a current limiting function, and includes a current limiting device such as a current limiter or a current limiting resistor. When the current limiting unit 150 is a current limiting resistor, the number of the current limiting resistors may be one or more, and the connection manner of the plurality of current limiting resistors may be series connection, parallel connection or series-parallel connection. In short, the present embodiment does not limit the specific device structure of each component.
It should be noted that the first output end of the energy storage circuit may be an output positive electrode or an output negative electrode, and the polarity of the first output end of the energy storage circuit is the same as that of the first end of the power grid. That is, when the first output terminal of the energy storage circuit is an output positive electrode, the first end of the power grid is a positive bus, and when the first output terminal of the energy storage circuit is an output negative electrode, the first end of the power grid is a negative bus.
Specifically, the first detection unit 110 collects a first voltage output by the tank circuit; the second detection unit 120 collects a second voltage output by the power grid, and the processor 130 obtains the first voltage and the second voltage, and outputs a control signal to control the first switch circuit 140 to be turned off when the first voltage is smaller than the second voltage. When the circuit is in an off-grid cut-in grid-connected state, the first voltage is smaller than the second voltage, and transient current flowing from the power grid side to the energy storage circuit side is generated. At this time, the processor 130 outputs a control signal to control the first switch circuit 140 to be switched off and connected to the current limiting circuit 150, so that the transient current generated when the off-grid switching-in grid-connection is performed can be reduced, the use safety of the energy storage system can be improved, the impact of the transient current on the load connected to the energy storage circuit can be reduced, and the service life of the load can be prolonged.
In addition, when the first voltage is equal to the second voltage, the first voltage is in an off-grid state or a state after grid connection is stable, and at this time, the processor 130 outputs a control signal to control the first switch circuit 140 to be closed, so as to short-circuit the current limiting circuit 150, thereby reducing the consumption of electric energy and improving the energy utilization rate.
Further, in an embodiment, the processor 130 is further configured to output a control signal to control the first switch circuit 140 to turn off when the first voltage is greater than the second voltage and a difference between the first voltage and the second voltage is greater than a preset voltage threshold. When the first voltage is greater than the second voltage and the difference value between the first voltage and the second voltage is greater than the preset voltage threshold value, it is indicated that the voltage on the side of the energy storage circuit or the side of the power grid fluctuates, and the current limiting circuit 150 is accessed at this moment, so that the influence caused by the voltage fluctuation can be reduced, the impact of the voltage fluctuation on the load on the side of the power grid can be reduced, and the service life of the load can be prolonged.
In one embodiment, as shown in fig. 2, the current limiting circuit further comprises a second switching circuit 160, the second switching circuit 160 being connected to the second output terminal of the tank circuit, the processor 130 and the second terminal of the grid; the first detection unit 110 is further configured to collect a first current output by the tank circuit; the second detection unit 120 is further configured to collect a second current output by the power grid; the processor 130 is further configured to obtain the first current and the second current, and output a control signal to control the second switch circuit 160 to turn off when the first current and/or the second current is greater than or equal to a preset current threshold.
The second switch circuit 160 is a circuit unit including a switch device, which may be a transistor or a relay. It is understood that the first detecting unit 110 and the second detecting unit 120 may be the same type of detecting unit or different types of detecting units, and similarly, the first switch circuit 140 and the second switch circuit 160 may be the same type of switch circuit or different types of switch circuits.
As mentioned above, the first output of the tank circuit and the first end of the grid have the same polarity, and therefore the second output of the tank circuit and the second end of the grid have the same polarity. For convenience of understanding, the following embodiments are all described with the first output terminal of the energy storage circuit being an output positive electrode, the second output terminal being an output negative electrode, the first end of the power grid being a positive bus, and the second end being a negative bus.
Specifically, when the first current and/or the second current is greater than or equal to the preset current threshold, if the first switch circuit 140 is in the open state, it indicates that the current in the circuit is still too large even after current limiting is performed, and if the first switch circuit 140 is in the closed state, it indicates that overcurrent may be caused by parallel use of a plurality of energy storage circuits. At this time, the processor 130 outputs the control signal to control the first switch circuit 140 and the second switch circuit 160 to be turned off, so as to cut off the whole loop, thereby avoiding the device damage caused by the excessive current and further improving the use safety of the energy storage system.
Further, after the processor 130 controls the first switch circuit 140 and the second switch circuit 160 to be turned off for a preset time, the processor outputs a control signal again to control the second switch circuit 160 to be turned on, the first detection unit 110 and the second detection unit 120 collect the first current and the second current again, and if the first current and/or the second current is still greater than or equal to the preset current threshold, the second switch circuit 160 is turned off again, and the restart failure count is performed. If three consecutive restarts fail, the processor 130 does not attempt a restart and the circuitry stops functioning.
In one embodiment, with continued reference to fig. 2, the first switch circuit 140 includes a first driving unit 141 and a first switch unit 142, the first driving unit 141 is connected to the control terminal of the first switch unit 142 and the processor 130, a first contact of the first switch unit 142 is connected to the first output terminal of the energy storage circuit, and a second contact of the first switch unit 142 is connected to the first terminal of the power grid; the second switch circuit 160 includes a second driving unit 161 and a second switch unit 162, the second driving unit 161 is connected to the control terminal of the second switch unit 162 and the processor 130, a first contact of the second switch unit 161 is connected to the second output terminal of the energy storage circuit, and a second contact of the second switch unit 142 is connected to the second terminal of the power grid.
The first switch unit 142 and the second switch unit 162 may be a relay, a triode, or a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS Transistor), etc. The first driving unit 141 and the second driving unit 161 are circuit units that convert the control signals output from the processor 130 into electrical signals that can be recognized by the corresponding switch units and output the electrical signals to the corresponding switch units. According to the types of the first and second switching units 142 and 162, the types of the first and second driving units 141 and 161 may be determined correspondingly. In short, the present embodiment does not limit the types of the circuit units.
Specifically, the processor 130 sends a control signal to the control terminal of the first switch unit 142 through the first driving unit 141 to control the first contact and the second contact of the first switch unit 142 to be opened or closed, and sends a control signal to the control terminal of the second switch unit 162 through the second driving unit 161 to control the first contact and the second contact of the second switch unit 162 to be opened or closed.
In the above embodiment, the first driving unit 141 and the second driving unit 161 are configured to perform the conversion of the processing of the control signal, which is beneficial to improving the reliability of the processor 130 for controlling the switch circuit, and further improving the safety of the circuit system.
In one embodiment, the first switch unit 142 and the second switch unit 162 are both controllable dc contactors. The controllable direct current contactor is a contactor in which the current of a main contact connecting loop is direct current and the opening and closing state of the main contact is controllable. Because the attraction coil of the controllable direct current contactor is electrified with direct current, no impact starting current exists, and the phenomenon of violent impact of an iron core can not be generated, so that the controllable direct current contactor has long service life and is suitable for occasions with frequent starting and stopping. Using a controllable dc contactor as the first switch unit 142 and the second switch unit 162 can further improve the service life of the circuit system.
In one embodiment, as shown in fig. 3, an energy storage system is provided, which includes an energy storage circuit 200 and the current limiting circuit 100 in the above embodiment, wherein the energy storage circuit 200 is connected to the current limiting circuit 100. For specific limitations of the current limiting circuit 100, reference is made above, and details are not repeated here. The energy storage circuit 200 is a circuit having an energy storage function, and protects an energy storage element such as a battery or a capacitor. Specifically, the number of the tank circuits 200 is not limited to one, and may be one, or a plurality of tank circuits 200 may be connected in parallel and then connected to the current limiting circuit 100. In the off-grid state, energy is supplied by tank circuit 200.
The energy storage system comprises the current limiting circuit 100, so that when the energy storage system is disconnected from the grid, i.e. the first voltage output by the energy storage circuit 200 is smaller than the second voltage output by the grid, the processor 130 outputs a control signal to control the first switch circuit 140 to be disconnected, so that the current limiting unit 150 is connected to the circuit, the consumption of the potential difference between the grid and the energy storage circuit 200 is facilitated, the instantaneous impact current is reduced, and the use safety of the energy storage system is improved.
In one embodiment, as shown in fig. 4, the tank circuit 200 includes a tank power supply 210, a converter circuit 220 and an output regulation circuit 230, the converter circuit 220 is connected to the tank power supply 210 and the output regulation circuit 230, and the output regulation circuit 230 is connected to the current limiting circuit 100.
The energy storage power source 210 may be an energy storage battery or a super capacitor. When the energy storage power source 210 is an energy storage battery pack, it may be any one of a lithium battery, a lead-acid battery, a lead-carbon battery, and the like, or a mixture of two or more batteries. The conversion circuit 220 may be a voltage boosting circuit or a voltage dropping circuit. The output voltage stabilizing circuit 230 may be a circuit unit formed by a voltage regulator tube or a voltage stabilizing capacitor. When the output voltage stabilizing circuit 230 is a voltage stabilizing capacitor, the number of the voltage stabilizing capacitors may be one or more, and the connection manner of the voltage stabilizing capacitors may be series connection, parallel connection or series-parallel connection. Further, the voltage stabilizing capacitor may be a polar capacitor or a non-polar capacitor. Specifically, the electric energy output by the energy storage power supply 210 is processed by the conversion circuit 220 and the output voltage stabilizing circuit 230, and then output to the load.
In the above embodiment, the configuration conversion circuit 220 converts the electric energy output by the energy storage power supply 210, and the configuration output voltage stabilizing circuit 230 performs voltage stabilizing processing on the converted electric energy, which is beneficial to improving the stability of the electric energy output by the energy storage circuit 200.
In one embodiment, with continued reference to fig. 4, the energy storage circuit 200 further includes an input regulation circuit 240, and the input regulation circuit 240 is connected to the energy storage power supply 210 and the conversion circuit 220. For the specific limitation of the input voltage stabilizing circuit 240, reference is made to the output voltage stabilizing circuit 230, which is not described herein again. Specifically, the electric energy output by the energy storage power supply 210 is processed by the input voltage stabilizing circuit 240, the converting circuit 220 and the output voltage stabilizing circuit 230 in sequence, and then output to the load.
In the above embodiment, the input voltage stabilizing circuit 240 is configured to perform voltage stabilization on the electric energy output by the energy storage power supply 210, which is beneficial to further improving the stability of the electric energy output by the energy storage circuit 200.
In one embodiment, the conversion circuit 220 is a boost circuit. The boost circuit is also called a bootstrap circuit, and refers to a circuit with an output voltage greater than an input voltage. The boost circuit generally comprises electronic components such as a bootstrap boost diode and a bootstrap boost capacitor, and the effect of boosting the output voltage is achieved by controlling the superposition of the discharge voltage of the bootstrap boost capacitor and the output voltage of the power supply.
In the above embodiment, the boost circuit is used as the conversion circuit in the energy storage circuit, and due to the boost function of the boost circuit, the output voltage of the boost circuit is greater than the output voltage of the energy storage power supply, so that even if the output voltage of the energy storage power supply is insufficient, the normal operation of the load can be maintained, the performance requirement of the load on the energy storage power supply can be reduced, the cost can be reduced, and the application scene of the energy storage circuit can be expanded.
In one embodiment, as shown in fig. 5, the boost circuit includes a first inductor L1, a second inductor L2, a first switching component S1, a second switching component S2, a third switching component S3, and a fourth switching component S4. The control ends of the first switch assembly S1, the second switch assembly S2, the third switch assembly S3 and the fourth switch assembly S4 are all connected with a main controller; a first end of the first inductor L1 is connected to the positive electrode of the energy storage power supply 210, a second end of the first inductor L1 is connected to a first end of the first switching component S1 and a first end of the third switching component S3, and a second end of the first switching component S1 is connected to the current limiting circuit 100; a second terminal of the third switching component S3 is connected to the negative terminal of the energy storage power supply 210 and the current limiting circuit 100. A first end of the second inductor L2 is connected to the positive electrode of the energy storage power supply 210, a second end of the second inductor L2 is connected to the first end of the second switching element S2 and the first end of the fourth switching element S4, and a second end of the second switching element S2 is connected to the current limiting circuit 100; a second end of the fourth switching component S4 is connected to the negative terminal of the energy storage power supply 210 and the current limiting circuit 100.
Each switch component may be a triode, a MOS Transistor, or an IGBT (Insulated Gate Bipolar Transistor). When each switch component is an MOS transistor, the MOS transistor may be a PMOS transistor or an NMOS transistor, and the types of the switch components may be the same or different. For convenience of understanding, the current inflow end of each switch assembly is taken as a first end, and the current outflow end is taken as a second end according to the current direction. For example, when the switch element is a PMOS transistor, the first terminal of the switch element is a drain, and the second terminal is a source; when the switch element is an NMOS transistor, the first terminal of the switch element is a source and the second terminal is a drain.
Specifically, the main controller controls the first switching assembly S1, the second switching assembly S2, the third switching assembly S3 and the fourth switching assembly S4 to be alternately closed. When the first switch component S1 and the fourth switch component S4 are closed and the second switch component S2 and the third switch component S3 are open, the loop where the first inductor L1 is located discharges and the loop where the second inductor L2 is located charges; when the second switching element S2 and the third switching element S3 are closed and the first switching element S1 and the fourth switching element S4 are opened, the loop of the first inductor L1 is charged and the loop of the second inductor L2 is discharged. The two boosting circuit units work alternately, and continuous power supply of the load in an off-grid state can be ensured. Further, in the grid-connected state, the energy storage circuit 200 is switched to the standby mode, and the main controller outputs a control signal with a small duty ratio to each switching element.
In the above embodiment, by optimizing the circuit structure of the boost circuit, the main controller can achieve the effect of uninterrupted boost output by controlling different switch assemblies in the circuit, and can ensure continuous power supply of the load in an off-grid state.
For ease of understanding, the detailed structure and operation of the energy storage system will be described below with reference to fig. 6. As shown in fig. 6, the energy storage circuit 200 includes a battery pack E1, a first voltage-stabilizing capacitor C1, a first inductor L1, a second inductor L2, a first switch component S1, a second switch component S2, a third switch component S3, a fourth switch component S4, and a second voltage-stabilizing capacitor C2. The current limiting circuit 100 includes a first detecting unit 110, a second detecting unit 120, a processor 130, a first driving unit 141, a first switch K1, a second driving unit 161, a second switch K2, and a current limiting resistor R1. The first switch component S1 and the second switch component S2 are NMOS tubes, the third switch component S3 and the fourth switch component S4 are PMOS tubes, the first switch K1 and the second switch K2 are controllable direct-current contactors, and the current-limiting resistor R1 is a cement resistor.
Specifically, the first voltage-stabilizing capacitor C1 is connected between the positive electrode and the negative electrode of the battery pack E1, the first end of the first inductor L1 is connected to the positive electrode of the battery pack E1, the second end of the first inductor L1 is connected to the source of the first switch component S1 and the drain of the third switch component S3, and the drain of the first switch component S1 is connected to the first contact of the first switch K1; the source of the third switch assembly S3 is connected to the negative terminal of the battery E1 and the first contact of the second switch K2. A first end of the second inductor L2 is connected to the anode of the battery pack E1, a second end of the second inductor L2 is connected to the source of the second switch component S2 and the drain of the fourth switch component S4, and the drain of the second switch component S2 is connected to the first contact of the first switch K1; the source of the fourth switch assembly S4 connects the negative terminal of the battery pack E1 and the first contact of the second switch K2. The second stabilizing capacitor C2 connects the first contact of the first switch K1 and the first contact of the second switch K2. And the grid electrode of each switch assembly is connected with the main controller.
The processor 130 is connected to the first detecting unit 110, the second detecting unit 120, the first driving unit 141, and the second driving unit 161. The first driving unit 141 is connected to a control terminal of the first switch K1, and the second driving unit 161 is connected to a control terminal of the second switch K2. A first contact of the first switch K1 is connected to the positive output of the tank circuit 200, and a second contact of the first switch K1 is connected to the positive grid BUS +. The first contact of the second switch K2 is connected with the output cathode of the energy storage circuit 200, and the second contact of the second switch K2 is connected with the negative BUS-of the power grid. The current limiting resistor R1 is connected between the positive output of the tank circuit 200 and the positive grid BUS +. The first detection unit 110 and the second detection unit 120 are respectively connected to the positive output electrode of the energy storage circuit 200 and the positive BUS + of the power grid through corresponding induction coils.
Specifically, the first detection unit 110 is configured to collect a first voltage and a first current output by the tank circuit 200. The second detecting unit 120 is configured to collect a second voltage and a second current output by the power grid. And under the off-grid switching and grid-connecting state, the first voltage is smaller than the second voltage, and transient current flowing from the power grid side to the energy storage circuit side is generated. At this time, the processor 130 outputs a control signal to control the first contact and the second contact of the first switch K1 to be disconnected, and the first contact and the second contact are connected to the current limiting resistor R1, so that the transient current generated when the off-grid connection and the grid connection are connected can be reduced, the use safety of the energy storage system can be improved, the impact of the transient current on the load connected to the energy storage circuit can be reduced, and the service life of the load can be prolonged.
After the off-grid state or the grid connection is stable, the first voltage is equal to the second voltage, the processor 130 outputs a control signal to control the first contact and the second contact of the first switch K1 to be closed, the current-limiting resistor R1 is short-circuited, the consumption of electric energy can be reduced, and the energy utilization rate is improved.
When the voltage of the energy storage circuit side or the power grid side fluctuates, the first voltage is greater than the second voltage, the difference value between the first voltage and the second voltage is greater than the preset voltage threshold value, the processor 130 outputs a control signal to control the disconnection of the first contact and the second contact of the first switch K1, the current limiting resistor R1 is connected, the influence caused by voltage fluctuation can be reduced, meanwhile, the impact of voltage fluctuation on the load on the power grid side is favorably reduced, and the service life of the load is prolonged.
In addition, when the first current and/or the second current is greater than or equal to the preset current threshold, if the first contact and the second contact of the first switch K1 are in an open state, it indicates that the current in the circuit is still too large even after current limiting is performed, and if the first contact and the second contact of the first switch K1 are in a closed state, it indicates that overcurrent may be caused by parallel use of a plurality of energy storage circuits. At this time, the processor 130 outputs the control signal to control the first switch K1 and the second switch K2 to be turned off, so as to cut off the whole loop, thereby avoiding the device damage caused by the excessive current and further improving the use safety of the energy storage system.
Further, after the processor 130 controls the first switch K1 and the second switch K2 to be turned off for a preset time, the processor outputs a control signal again to control the second switch K2 to be turned on, the first detection unit 110 and the second detection unit 120 collect the first current and the second current again, and if the first current and/or the second current are still greater than or equal to the preset current threshold, the second switch K2 is turned off again, and the restart failure count is performed. If the restart fails for three times, the processor 130 does not try to restart, and the circuit system stops working, so that the circuit is prevented from being impacted by large current, and the use safety of the energy storage system is further improved.
In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (11)

1. A current limiting circuit is characterized by comprising a first detection unit, a second detection unit, a processor, a first switch circuit and a current limiting unit;
the first detection unit is connected with the energy storage circuit, and the second detection unit is connected with the power grid; the processor is connected with the first detection unit, the second detection unit and the first switch circuit; the first switch circuit is connected with a first output end of the energy storage circuit and a first end of the power grid; the current limiting unit is connected with a first output end of the energy storage circuit and a first end of the power grid;
the first detection unit is used for collecting a first voltage output by the energy storage circuit; the second detection unit is used for collecting a second voltage output by the power grid; the processor is used for obtaining the first voltage and the second voltage and outputting a control signal to control the first switch circuit to be switched off when the first voltage is smaller than the second voltage.
2. The current limiting circuit of claim 1 further comprising a second switching circuit coupled to the second output of the tank circuit, the processor, and the second end of the power grid;
the first detection unit is also used for collecting a first current output by the energy storage circuit; the second detection unit is also used for collecting a second current output by the power grid; the processor is further configured to obtain the first current and the second current, and output a control signal to control the first switch circuit and the second switch circuit to be turned off when the first current and/or the second current is greater than or equal to a preset current threshold.
3. The current-limiting circuit of claim 2, wherein the first switching circuit comprises a first driving unit and a first switching unit, the first driving unit is connected with a control terminal of the first switching unit and the processor, a first contact of the first switching unit is connected with a first output terminal of the energy storage circuit, and a second contact of the first switching unit is connected with a first terminal of the power grid;
the second switch circuit comprises a second driving unit and a second switch unit, the second driving unit is connected with the control end of the second switch unit and the processor, the first contact of the second switch unit is connected with the second output end of the energy storage circuit, and the second contact of the second switch unit is connected with the second end of the power grid.
4. The current-limiting circuit of claim 3, wherein the first switching unit and the second switching unit are both controllable DC contactors.
5. The current-limiting circuit of claim 1, wherein the current-limiting unit is a current-limiting resistor.
6. The current-limiting circuit of any one of claims 1 to 5, wherein the processor is further configured to output a control signal to control the first switch circuit to turn off when the first voltage is greater than the second voltage and a difference between the first voltage and the second voltage is greater than a preset voltage threshold.
7. An energy storage system, comprising an energy storage circuit and a current limiting circuit according to any one of claims 1 to 6, wherein the energy storage circuit is connected to the current limiting circuit.
8. The energy storage system of claim 7, wherein the energy storage circuit comprises an energy storage power supply, a conversion circuit and an output voltage stabilizing circuit, the conversion circuit is connected with the energy storage power supply and the output voltage stabilizing circuit, and the output voltage stabilizing circuit is connected with the current limiting circuit.
9. The energy storage system of claim 8, the conversion circuit being a boost circuit.
10. The energy storage system of claim 9, the boost circuit comprising a first inductor, a second inductor, a first switching assembly, a second switching assembly, a third switching assembly, and a fourth switching assembly;
the control ends of the first switch assembly, the second switch assembly, the third switch assembly and the fourth switch assembly are all connected with a main controller;
the first end of the first inductor is connected with the anode of the energy storage power supply, the second end of the first inductor is connected with the first end of the first switch component and the first end of the third switch component, and the second end of the first switch component is connected with the current limiting circuit; the second end of the third switch component is connected with the negative electrode of the energy storage power supply and the current limiting circuit;
the first end of the second inductor is connected with the anode of the energy storage power supply, the second end of the second inductor is connected with the first end of the second switch component and the first end of the fourth switch component, and the second end of the second switch component is connected with the current limiting circuit; and the second end of the fourth switch component is connected with the negative electrode of the energy storage power supply and the current limiting circuit.
11. The energy storage system of any of claims 8 to 10, the energy storage circuit further comprising an input voltage stabilizing circuit, the input voltage stabilizing circuit connecting the energy storage power supply and the conversion circuit.
CN202110250659.2A 2021-03-08 2021-03-08 Current limiting circuit and energy storage system Pending CN112886640A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110250659.2A CN112886640A (en) 2021-03-08 2021-03-08 Current limiting circuit and energy storage system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110250659.2A CN112886640A (en) 2021-03-08 2021-03-08 Current limiting circuit and energy storage system

Publications (1)

Publication Number Publication Date
CN112886640A true CN112886640A (en) 2021-06-01

Family

ID=76055701

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110250659.2A Pending CN112886640A (en) 2021-03-08 2021-03-08 Current limiting circuit and energy storage system

Country Status (1)

Country Link
CN (1) CN112886640A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113760028A (en) * 2021-07-19 2021-12-07 许继集团有限公司 Energy taking power supply and energy taking method of flexible and straight submodule
CN114121550A (en) * 2021-10-13 2022-03-01 华为数字能源技术有限公司 Circuit switch, energy storage system and related control method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113760028A (en) * 2021-07-19 2021-12-07 许继集团有限公司 Energy taking power supply and energy taking method of flexible and straight submodule
CN114121550A (en) * 2021-10-13 2022-03-01 华为数字能源技术有限公司 Circuit switch, energy storage system and related control method

Similar Documents

Publication Publication Date Title
CN110224381B (en) Photovoltaic inverter and photovoltaic power generation system thereof
CN108075562B (en) High-power portable electric equipment and power supply control device and method thereof
CN110676918A (en) Battery switch circuit, power supply management system and method
CN112886640A (en) Current limiting circuit and energy storage system
CN112491255A (en) Voltage-sharing circuit, flying capacitor three-level converter and equipment
CN112737041A (en) Battery series charging and discharging circuit and charging and discharging control method
CN210640722U (en) Battery switch circuit and power supply management system comprising same
CN113328484A (en) Charging module, charging control method and device
CN206116318U (en) Drive power supply of repulsion mechanism
CN103368235B (en) Nickel-metal hydride battery charge-discharge circuit in uninterruptible power supply
CN113629854A (en) Lithium battery power supply system with linear dynamic charging current-limiting function for communication equipment
CN111817535B (en) Standby zero-power-consumption switching power supply and electric equipment
CN110061559B (en) Off-line uninterrupted power supply and control method thereof
JP2009148110A (en) Charger/discharger and power supply device using the same
CN117394671A (en) Energy-taking power supply topology and method for series connection application of energy-taking power supply topology and power module voltage-equalizing resistor
CN214506569U (en) Current limiting circuit and energy storage system
EP4135153B1 (en) Battery cell balance circuit and method of operating the same
CN116316761A (en) Energy storage cabinet and energy storage system
CN203671834U (en) Soft start charging circuit
CN214590546U (en) Multi-mode combined power-taking and energy-supplying module for intelligent circuit breaker
CN214799289U (en) Power-off discharge circuit of power supply
WO2022217721A1 (en) Smart battery
CN114400751A (en) Battery group parallel system, control method and storage medium
CN110061560B (en) Off-line uninterrupted power supply and control method thereof
CN114655071A (en) Battery, battery control method and electric vehicle

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