Current protection circuit of energy storage converter and energy storage converter

Abstract

The utility model relates to the technical field of energy storage circuits, and provides a current protection circuit of an energy storage converter and the energy storage converter, and the current protection circuit of the energy storage converter comprises a direct current contactor which is connected between a direct current side inductance voltage and a direct current input voltage so as to control the input of the direct current input voltage; the current protection module is connected to the direct current contactor in parallel, when the direct current contactor is closed, impact current protection is carried out, and the current protection module comprises a first resistor, a direct current relay and an inductor which are sequentially connected in series. According to the technical scheme, the direct-current contactor is prevented from generating impact current when being closed, so that the direct-current contactor and the energy storage converter are prevented from being influenced by the impact current.

Description

[Technical field]

[0001] The utility model relates to the technical field of energy storage circuits, in particular to a current protection circuit of an energy storage converter and an energy storage converter. [Background technology]

[0002] With the vigorous development of new energy and energy storage industries, during the operation of energy storage power stations, the energy storage inverter is the most core power conversion component in the energy storage power station. The working stability of the energy storage inverter is related to whether the energy storage power station can operate normally and stably.

[0003] In the energy storage inverter, the DC contactor is a key component of the energy storage inverter, which is used to control whether the circuit between the battery pack corresponding to the energy storage inverter and the power board at the rear end of the energy storage inverter is turned on. At the DC port of the energy storage inverter, because there is a voltage difference between the two ends of the DC contactor, a huge impact current will be generated at the moment when the DC contactor is opened and closed. This impact current will have a serious impact on the reliability of the DC contactor and even the entire energy storage inverter. Therefore, in the current energy storage inverter, the protection ability of the DC contactor against impact current is relatively weak. How to avoid the impact current generated by the DC contactor at the moment of closing is a technical problem that needs to be solved urgently. [Contents of the utility model]

[0004] The embodiment of the utility model provides a current protection circuit of an energy storage converter and an energy storage converter, aiming to solve the technical problem existing in the related art that a DC contactor generates an impact current at the moment of closing, which affects the reliability of the contactor and the entire energy storage converter.

[0005] In a first aspect, an embodiment of the utility model provides a current protection circuit of an energy storage converter, comprising: a DC contactor and a current protection module;

[0006] The DC contactor is connected between the DC side inductor voltage and the DC input voltage to control the input of the DC input voltage;

[0007] The current protection module is connected in parallel to the DC contactor, and performs surge current protection when the DC contactor is closed, wherein the current protection module includes a first resistor, a DC relay, and an inductor connected in series in sequence.

[0008] In one embodiment, optionally, the first resistor has a first end connected to the positive electrode of the DC side inductor voltage, and a second end connected to the DC relay;

[0009] The DC relay is connected between the first resistor and the inductor;

[0010] The inductor has a first end connected to the DC relay and a second end connected to the first end of the DC input voltage.

[0011] In one embodiment, optionally, it further includes: a second resistor;

[0012] The first end of the second resistor is connected to the second end of the inductor, and the second end of the second resistor is connected to the second end of the DC input voltage.

[0013] In one embodiment, optionally, it further includes: a capacitor;

[0014] The capacitor is connected between the first end and the second end of the DC input voltage and is used for filtering the DC input voltage.

[0015] In one embodiment, optionally, it further includes: a switch controller;

[0016] The switch controller is connected to the DC relay and is used to control the DC relay to be in an open state or a closed state.

[0017] In one embodiment, optionally, it further includes:

[0018] a first voltage sensor and a second voltage sensor;

[0019] The first voltage sensor is disposed at the first end of the DC contactor, and is used to collect a first voltage value at the first end of the DC contactor;

[0020] The second voltage sensor is disposed at the second end of the DC contactor, and is used to collect a second voltage value at the second end of the DC contactor;

[0021] The information receiving end of the switch controller is connected to the signal output end of the first voltage sensor and the signal output end of the second voltage sensor respectively, and is used to receive the first voltage value and the second voltage value.

[0022] In one embodiment, optionally, the switch controller has a remote communication port for connecting to a remote host computer to establish a communication connection between the switch controller and the host computer.

[0023] In one embodiment, optionally, it further includes: a switch control circuit;

[0024] The DC contactor switch control terminal of the switch controller is connected to the input terminal of the switch control circuit, and is used to send a switch control signal to the switch control circuit;

[0025] The output end of the switch control circuit is connected to the controlled end of the DC contactor, and is used to close the DC contactor when the received switch control signal is a high-level signal, and to open the DC contactor when the received switch control signal is a low-level signal.

[0026] In one embodiment, optionally, the switch control circuit includes a voltage comparator, an inverter and an AND gate circuit;

[0027] The non-inverting input terminal of the voltage comparator is connected to the second terminal of the DC contactor, and the inverting input terminal of the voltage comparator is connected to the first terminal of the DC contactor;

[0028] The output end of the voltage comparator is connected to the input end of the inverter, the output end of the inverter is connected to the first receiving end of the AND gate circuit, the second receiving end of the AND gate circuit is connected to the DC contactor switch control end of the switch controller, and the output end of the AND gate circuit is connected to the controlled end of the DC contactor.

[0029] In a second aspect, an embodiment of the utility model provides an energy storage converter, comprising a current protection circuit of the energy storage converter described in any one of the embodiments of the first aspect.

[0030] In the above current protection circuit of the energy storage converter and the scheme implemented by the energy storage converter, the current protection circuit of the energy storage converter includes a DC contactor and a current protection module; the DC contactor is connected between the DC side inductor voltage and the DC input voltage to control the input of the DC input voltage; the current protection module is connected in parallel to the DC contactor, and when the DC contactor is closed, the impact current protection is performed, wherein the current protection module includes a first resistor, a DC relay and an inductor connected in series in sequence. In the utility model, the current protection module is connected in parallel to the two ends of the DC contactor, and specifically, the current protection module includes a first resistor, a DC relay and an inductor connected in series in sequence. In this way, before the DC contactor needs to be closed, the DC relay is closed first. After the DC relay is closed, the current is delayed due to the presence of the inductor. At this time, the voltage difference at both ends of the DC contactor is zero. Closing the DC contactor can avoid the generation of impact current, thereby avoiding the DC contactor from generating impact current when it is closed, so that the DC contactor and the energy storage converter are protected from the impact current.

Brief Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 One of the structural schematic diagrams of a protection circuit of a DC contactor provided by an embodiment of the utility model is shown;

[0033] Figure 2 A second structural schematic diagram of a protection circuit of a DC contactor provided by an embodiment of the utility model is shown;

[0034] Figure 3 A third structural schematic diagram of a protection circuit of a DC contactor provided by an embodiment of the utility model is shown;

[0035] Figure 4 A structural schematic diagram of a switch control circuit provided by an embodiment of the utility model is shown. [Specific implementation method]

[0036] In order to better understand the technical solution of the present utility model, the embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0037] It should be clear that the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0039] In order to solve the technical problems in the related art that the sampling equipment with filtering function is high in cost and does not meet the needs of mass production, the utility model proposes an energy storage converter and an energy storage system.

[0040] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0041] See also Figure 1 , Figure 1 The structure diagram of the current protection circuit of the energy storage converter according to one embodiment of the utility model is shown. The current protection circuit of the energy storage converter is used to protect the DC contactor inside the energy storage converter from impact current.

[0042] like Figure 1As shown, a current protection circuit of an energy storage converter according to an embodiment of the utility model includes:

[0043] DC contactor 4 and current protection module;

[0044] The DC contactor is connected between the DC side inductor voltage and the DC input voltage to control the input of the DC input voltage;

[0045] The current protection module is connected in parallel to the DC contactor, and performs surge current protection when the DC contactor is closed, wherein the current protection module includes a first resistor 1, a DC relay 2, and an inductor 3 connected in series in sequence.

[0046] In one embodiment, optionally, the first resistor 1 has a first end connected to the positive electrode of the DC side inductor voltage, and a second end connected to the DC relay;

[0047] The DC relay 2 is connected between the first resistor and the inductor;

[0048] The inductor 3 has a first end connected to the DC relay, and a second end connected to the first end of the DC input voltage.

[0049] A current protection circuit for an energy storage converter proposed in an embodiment of the utility model closes the DC relay before the DC contactor needs to be closed. After the DC relay is closed, a phase difference will exist between the voltage and the current due to the inductance characteristic. That is to say, the existence of the inductance causes a lag in the current. Therefore, within the phase difference, the voltage difference across the DC contactor is zero. Closing the DC contactor at this time can avoid the generation of impact current, thereby avoiding the generation of impact current when the DC contactor is closed, protecting the DC contactor and the energy storage converter from the impact of the impact current, and thereby improving the operating stability of the DC contactor and the energy storage converter.

[0050] In one embodiment, optionally, it further includes: a second resistor 5;

[0051] The first end of the second resistor 5 is connected to the second end of the inductor, and the second end is connected to the second end of the DC input voltage.

[0052] In one embodiment, optionally, it further includes: a capacitor 6;

[0053] The capacitor 6 is connected between the first end and the second end of the DC input voltage, and is used to filter the DC input voltage.

[0054] In one embodiment, optionally, it further includes: a switch controller 7;

[0055] The switch controller 7 is connected to the DC relay 2 and is used to control the DC relay 2 to be in an open state or a closed state.

[0056] In one embodiment, optionally, it further includes:

[0057] A first voltage sensor V1 and a second voltage sensor V2;

[0058] The first voltage sensor V1 is disposed at the first end of the DC contactor 4, and is used to collect a first voltage value at the first end of the DC contactor;

[0059] The second voltage sensor V2 is disposed at the second end of the DC contactor 4, and is used to collect a second voltage value at the second end of the DC contactor;

[0060] The information receiving end of the switch controller 7 is connected to the signal output end of the first voltage sensor V1 and the signal output end of the second voltage sensor V2 respectively, and is used to receive the first voltage value and the second voltage value.

[0061] In one embodiment, optionally, the switch controller has a remote communication port for connecting to a remote host computer to establish a communication connection between the switch controller and the host computer.

[0062] In one embodiment, optionally, it further includes: a switch control circuit 8;

[0063] The DC contactor switch control terminal of the switch controller 7 is connected to the input terminal of the switch control circuit 8, and is used to send a switch control signal to the switch control circuit;

[0064] The output end of the switch control circuit 8 is connected to the controlled end of the DC contactor 4, and is used to close the DC contactor 4 when the received switch control signal is a high level signal, and to open the DC contactor 4 when the received switch control signal is a low level signal.

[0065] In one embodiment, optionally, the switch control circuit 8 includes a voltage comparator, an inverter and an AND gate circuit;

[0066] The non-inverting input terminal of the voltage comparator is connected to the second terminal of the DC contactor, and the inverting input terminal of the voltage comparator is connected to the first terminal of the DC contactor;

[0067] The output end of the voltage comparator is connected to the input end of the inverter, the output end of the inverter is connected to the first receiving end of the AND gate circuit, the second receiving end of the AND gate circuit is connected to the DC contactor switch control end of the switch controller, and the output end of the AND gate circuit is connected to the controlled end of the DC contactor.

[0068] In one embodiment, Figure 2 As shown, the protection circuit of the DC contactor also includes a switch controller; wherein the switch controller can be a computer device with certain computing capabilities, and the switch controller can have a human-computer interaction interface to enable an operator to operate the switch controller based on the human-computer interaction interface.

[0069] Further, the switch controller is connected to the DC relay, and is used to control the DC relay to be in an open state or a closed state. Here, when the DC relay needs to be closed, the relevant operator can control the switch controller to control the DC relay to be closed, and when the DC relay needs to be opened, the relevant operator can control the switch controller to control the DC relay to be opened. In the embodiment provided by the present application, the opening and closing of the DC relay can be controlled by the switch controller, thereby improving the operability of the protection circuit of the DC contactor.

[0070] In one embodiment, Figure 2 As shown, the protection circuit of the DC contactor further includes a first voltage sensor V1 and a second voltage sensor V2.

[0071] Specifically, the first voltage sensor V1 is arranged at the first end of the DC contactor to collect the first voltage value at the first end of the DC contactor; here, the first voltage sensor V1 can be a non-contact measurement voltage sensor, which is arranged at the wire at the first end of the DC contactor to collect the first voltage value at the first end of the DC contactor.

[0072] Furthermore, the second voltage sensor V2 is arranged at the second end of the DC contactor to collect the second voltage value at the second end of the DC contactor; here, the second voltage sensor V2 can also be a non-contact measurement voltage sensor, which is arranged at the wire at the second end of the DC contactor to collect the second voltage value at the second end of the DC contactor.

[0073] Furthermore, the information receiving end of the switch controller is respectively connected to the signal output end of the first voltage sensor V1 and the signal output end of the second voltage sensor V2, for receiving the first voltage value and the second voltage value. Here, the switch controller can determine whether the voltage difference across the DC contactor is too large based on a program pre-set in the switch controller, and when the voltage difference across the DC contactor is too large, prohibit the DC contactor from closing to protect the DC contactor. The embodiment provided by the present application can collect the voltage across the DC contactor, provide a hardware basis for the relevant program to identify whether the voltage difference across the DC contactor is too large, and improve the versatility of the protection circuit of the DC contactor.

[0074] In one embodiment, Figure 3 As shown, the switch controller has a remote communication port for connecting to a remote host computer to establish a communication connection between the switch controller and the host computer. The host computer may be a control computer or other equipment at a remote control center. Specifically, the remote communication port may be a bus communication interface or an optical fiber interface, so that the switch controller can exchange data with the host computer through the bus or optical fiber, so that the host computer can remotely control and adjust the program of the switch controller. The embodiment provided by the present application enables relevant staff to remotely control the opening and closing of the DC relay through the host computer, thereby improving the operational convenience of the protection circuit of the DC contactor.

[0075] In one embodiment, Figure 3 As shown, the protection circuit of the DC contactor also includes a switch control circuit; the DC contactor switch control terminal of the switch controller is connected to the input terminal of the switch control circuit, and is used to send a switch control signal to the switch control circuit.

[0076] Furthermore, the output end of the switch control circuit is connected to the controlled end of the DC contactor, and is used to close the DC contactor when the received switch control signal is a high-level signal, and to open the DC contactor when the received switch control signal is a low-level signal.

[0077] The embodiments provided in the present application can control the closing and opening of a DC relay and a DC contactor based on a switch control circuit. In an actual working process, before the DC contactor needs to be closed, the DC relay can be controlled to close first. When the voltage difference across the DC contactor is eliminated, the DC contactor can be controlled to close, thereby improving the operability of the protection circuit of the DC contactor.

[0078] In one embodiment, when the controlled end of the DC contactor receives a high level signal, the DC contactor is closed, and when the controlled end of the DC contactor receives a low level signal, the DC contactor is opened; further, Figure 4 As shown, the switch control circuit includes a voltage comparator, an inverter and an AND gate circuit.

[0079] Specifically, the non-inverting input terminal of the voltage comparator is connected to the second end of the DC contactor, and the inverting input terminal of the voltage comparator is connected to the first end of the DC contactor; here, the non-inverting input terminal of the voltage comparator is connected between the positive access terminal of the power board and the second end of the DC contactor, and the inverting input terminal of the voltage comparator is connected between the positive terminal of the battery pack and the first end of the DC contactor, so as to determine whether the voltage at the second end of the DC contactor is higher than the voltage at the first end of the DC contactor, and determine whether there is a voltage difference between the two ends of the DC contactor.

[0080] Furthermore, the output end of the voltage comparator is connected to the input end of the inverter, the output end of the inverter is connected to the first receiving end of the gate circuit, the second receiving end of the AND gate circuit is connected to the DC contactor switch control end of the switch controller, and the output end of the AND gate circuit is connected to the controlled end of the DC contactor.

[0081] Furthermore, in the actual working process, if the voltage at the second end of the DC contactor is higher than the voltage at the first end of the DC contactor, the voltage comparator outputs a high-level signal, and the high-level signal outputs a low-level signal after passing through the inverter, and the low-level signal is transmitted to the first receiving end of the AND gate circuit; further, if the DC contactor needs to be closed at this time, the DC contactor switch control end of the switch controller will send a high-level signal to the second receiving end of the AND gate circuit, but because the first receiving end of the AND gate circuit receives a low-level signal, the output end of the AND gate circuit cannot output a high-level signal, so that the DC contactor cannot be closed, so as to protect the DC contactor from inrush current.

[0082] Conversely, if the voltage at the second end of the DC contactor is not higher than the voltage at the first end of the DC contactor, the voltage comparator outputs a low-level signal, the low-level signal outputs a high-level signal after passing through the inverter, and the high-level signal is transmitted to the first receiving end of the AND gate circuit; further, if the DC contactor needs to be closed at this time, the DC contactor switch control end of the switch controller will send a high-level signal to the second receiving end of the AND gate circuit. At this time, the first receiving end of the AND gate circuit also receives a high-level signal, so that the output end of the AND gate circuit outputs a high-level signal to close the DC contactor.

[0083] In the embodiments provided by the present application, the protection circuit of the DC contactor can autonomously identify whether there is a voltage difference between the two ends of the DC contactor, and when there is a voltage difference in the DC contactor, the DC contactor cannot be closed, thereby further improving the protection capability of the DC contactor.

[0084] It should be noted that the internal circuit connection mode of the switch controller, the first voltage sensor, and the second voltage sensor can be determined according to the actual situation, and this embodiment does not make specific restrictions. In addition, the connection mode of each device can be determined according to the specific selection of the device, and this embodiment does not make specific restrictions. The circuit function of the protection circuit of the DC contactor provided in this embodiment is mainly realized by the circuit connection relationship between each circuit module, and does not rely on the program module in a certain circuit module. In addition, each circuit module in the protection circuit of the DC contactor can be realized by an analog circuit or a digital circuit, and for a switch controller that can be implanted with a program module, the realization of its module function can be realized by the program module provided by the prior art.

[0085] In a second aspect, an energy storage converter is provided, which is used for a current protection circuit of the energy storage converter described in any one of the embodiments of the first aspect.

[0086] It is understandable that the composition of the ADC sampling circuit, the selection of each component, and the signal type of the voltage signal can be selected and set according to the actual scenario of production design, and this embodiment does not make specific limitations.

[0087] It should be noted that the circuit function of the energy storage converter provided in this embodiment is mainly realized by the circuit connection relationship between the various circuit modules, and does not rely on the program module in a certain circuit module. In addition, each circuit module in the energy storage converter can be realized by an analog circuit or a digital circuit, and for the circuit module that can be implanted with a program module, the realization of its module function can be realized by the program module provided by the prior art.

[0088] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0089] It should be understood that, although the terms first, second, etc. may be used to describe the setting units in the embodiments of the present invention, these setting units should not be limited to these terms. These terms are only used to distinguish the setting units from each other. For example, without departing from the scope of the embodiments of the present invention, the first setting unit may also be referred to as the second setting unit, and similarly, the second setting unit may also be referred to as the first setting unit.

[0090] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0091] In the several embodiments provided by the present utility model, it should be understood that the disclosed systems, systems and methods can be implemented in other ways. For example, the system embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of systems or units, which can be electrical, mechanical or other forms.

[0092] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0093] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A current protection circuit for an energy storage converter, characterized in that: include: DC contactors and current protection modules; The DC contactor is connected between the DC side inductor voltage and the DC input voltage to control the input of the DC input voltage; The current protection module is connected in parallel to the DC contactor, and performs surge current protection when the DC contactor is closed, wherein the current protection module includes a first resistor, a DC relay, and an inductor connected in series in sequence.

2. The current protection circuit of the energy storage converter according to claim 1, characterized in that: The first resistor has a first end connected to the positive electrode of the DC side inductor voltage, and a second end connected to the DC relay; The DC relay is connected between the first resistor and the inductor; The inductor has a first end connected to the DC relay and a second end connected to the first end of the DC input voltage.

3. The current protection circuit of the energy storage converter according to claim 1, characterized in that: Also includes: A second resistor; The first end of the second resistor is connected to the second end of the inductor, and the second end of the second resistor is connected to the second end of the DC input voltage.

4. The current protection circuit of the energy storage converter according to claim 1, characterized in that: Also includes: capacitance; The capacitor is connected between the first end and the second end of the DC input voltage and is used for filtering the DC input voltage.

5. The current protection circuit of the energy storage converter according to claim 1, characterized in that: Also includes: Switch controller; The switch controller is connected to the DC relay and is used to control the DC relay to be in an open state or a closed state.

6. The current protection circuit of the energy storage converter according to claim 5, characterized in that: Also includes: a first voltage sensor and a second voltage sensor; The first voltage sensor is disposed at the first end of the DC contactor, and is used to collect a first voltage value at the first end of the DC contactor; The second voltage sensor is disposed at the second end of the DC contactor, and is used to collect a second voltage value at the second end of the DC contactor; The information receiving end of the switch controller is connected to the signal output end of the first voltage sensor and the signal output end of the second voltage sensor respectively, and is used to receive the first voltage value and the second voltage value.

7. The current protection circuit of the energy storage converter according to claim 5, characterized in that: The switch controller has a remote communication port for connecting to a remote host computer to establish a communication connection between the switch controller and the host computer.

8. The current protection circuit of the energy storage converter according to claim 5, characterized in that: Also includes: Switch control circuit; The DC contactor switch control terminal of the switch controller is connected to the input terminal of the switch control circuit, and is used to send a switch control signal to the switch control circuit; The output end of the switch control circuit is connected to the controlled end of the DC contactor, and is used to close the DC contactor when the received switch control signal is a high-level signal, and to open the DC contactor when the received switch control signal is a low-level signal.

9. The current protection circuit of the energy storage converter according to claim 8, characterized in that: The switch control circuit includes a voltage comparator, an inverter and an AND gate circuit; The non-inverting input terminal of the voltage comparator is connected to the second terminal of the DC contactor, and the inverting input terminal of the voltage comparator is connected to the first terminal of the DC contactor; The output end of the voltage comparator is connected to the input end of the inverter, the output end of the inverter is connected to the first receiving end of the AND gate circuit, the second receiving end of the AND gate circuit is connected to the DC contactor switch control end of the switch controller, and the output end of the AND gate circuit is connected to the controlled end of the DC contactor.

10. An energy storage converter, characterized in that: include: A current protection circuit for an energy storage converter according to any one of claims 1 to 9.

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