Protection circuit of direct current contactor and energy storage converter
By designing a protection circuit in the DC contactor, the voltage difference is slowly eliminated by using the current limiting resistor and the field effect tube, the problem of the DC contactor generating impact current at the moment of closing is solved, and its stability and reliability of the energy storage converter are improved.
Patent Information
- Application Number
- CN202421452865.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-24
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-06-24
AI Technical Summary
In energy storage converters, the DC contactor generates an impact current at the moment of closing, affecting its stability and reliability.
A protection circuit for a DC contactor is designed, including a current limiting resistor and a field effect tube. By controlling the conduction state of the field effect tube, the voltage difference between the two ends of the DC contactor is slowly eliminated, thereby avoiding the generation of impingement current.
It effectively avoids impact current generated by the DC contactor at the moment of closing, and improves the stability of the DC contactor and the overall reliability of the energy storage converter.
Smart Images
Figure CN222867548U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of energy storage converters and energy storage power stations, in particular to a protection circuit of a DC contactor and an energy storage converter. Background Art
[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 key problem that needs to be solved urgently. Utility Model Content
[0004] In view of this, the utility model provides a protection circuit for a DC contactor and an energy storage converter, the main purpose of which is to solve the technical problem that the DC contactor generates an impact current at the moment of closing, which affects the stability of the DC contactor.
[0005] To achieve the above object, the utility model first provides a protection circuit of a DC contactor, which is used to protect the DC contactor in an energy storage converter from impact current. The protection circuit of the DC contactor includes a current limiting resistor and a field effect transistor, wherein the field effect transistor is used to be controlled to be in an on state or an off state;
[0006] The first end of the current limiting resistor is connected to the first end of the DC contactor, the second end of the current limiting resistor is connected to the source of the field effect transistor, and the drain of the field effect transistor is connected to the second end of the DC contactor.
[0007] In one embodiment of the present invention, the field effect transistor is an N-channel field effect transistor.
[0008] In one embodiment of the utility model, the protection circuit of the DC contactor further includes a switch controller; the control end of the switch controller is connected to the gate of the field effect tube, and is used to control the field effect tube to be in an on state or an off state.
[0009] In one embodiment of the utility model, the protection circuit of the DC contactor also includes a first voltage sensor and a second voltage sensor; the first voltage sensor is arranged 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 arranged 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 respectively connected to the signal output end of the first voltage sensor and the signal output end of the second voltage sensor, and is used to receive the first voltage value and the second voltage value.
[0010] In one embodiment of the present invention, 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.
[0011] In one embodiment of the utility model, the protection circuit of the DC contactor also includes a switch control circuit; the DC contactor switch control end of the switch controller is connected to the input end 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.
[0012] In one embodiment of the utility model, 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, characterized in that the switch control circuit includes a voltage comparator, an inverter and an AND gate circuit; the non-phase input end of the voltage comparator is connected to the second end of the DC contactor, and the inverting input end of the voltage comparator is connected to the first end 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.
[0013] In one embodiment of the utility model, the protection circuit of the DC contactor further includes an alarm device; the alarm output terminal of the switch controller is connected to the controlled terminal of the alarm device for controlling the alarm device to issue an alarm prompt message.
[0014] In one embodiment of the present invention, the alarm device is a buzzer or a flash light.
[0015] In addition, to achieve the above-mentioned purpose, the utility model also proposes an energy storage converter, including the protection circuit of the DC contactor as mentioned above.
[0016] The utility model provides a protection circuit of a DC contactor and an energy storage converter. Before the DC contactor needs to be closed, a voltage can be first transmitted to the gate of the field effect tube to turn on the field effect tube. By using the principle of slow conduction of the field effect tube, the current flowing through the field effect tube will gradually increase and eventually reach a stable state, thereby eliminating the voltage difference at both ends of the DC contactor, so that the DC contactor will not generate an impact current at the moment of closing. At the same time, a current-limiting resistor is connected in series with the field effect tube to prevent large currents from damaging the field effect tube. Further, after the voltage difference at both ends of the DC contactor is eliminated, the DC contactor can be closed. At this time, because of the existence of the current-limiting resistor, the current will pass through the DC contactor and interact between the battery pack corresponding to the energy storage converter and the power board at the rear end of the energy storage converter to realize the function of the DC contactor. The technical solution disclosed in the present application can eliminate the voltage difference at both ends of the DC contactor before the DC contactor is closed, avoid the DC contactor from generating an impact current when it is closed, and protect the DC contactor and the energy storage converter from the impact of the impact current.
[0017] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0019] 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;
[0020] 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;
[0021] 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;
[0022] Figure 4 A schematic diagram of the structure of a switch control circuit provided by an embodiment of the utility model is shown;
[0023] Figure 5 A fourth structural schematic diagram of a protection circuit for a DC contactor provided in an embodiment of the utility model is shown. DETAILED DESCRIPTION
[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.
[0025] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.
[0026] Combine the following Figures 1 to 5 The protection circuit of the DC contactor and the energy storage converter according to some embodiments of the utility model are described.
[0027] like Figure 1 As shown, a protection circuit of a DC contactor proposed in an embodiment of the utility model is used to protect the DC contactor inside the energy storage converter from impact current. Furthermore, the protection circuit of the DC contactor is applied to the peripheral circuit where the existing DC contactor is located, including a current limiting resistor and a field effect transistor. Here, the field effect transistor can be an N-channel field effect transistor, or a P-channel field effect transistor.
[0028] Specifically, the first end of the current limiting resistor is connected to the first end of the DC contactor, the second end of the current limiting resistor is connected to the source of the field effect tube, and the drain of the field effect tube is connected to the second end of the DC contactor; here, the first end of the DC contactor is used to connect to the positive terminal DC+ of the battery pack (not shown in the figure) corresponding to the energy storage converter, and the second end of the DC contactor is used to connect to the positive access terminal DC_IN+ of the power board (not shown in the figure) corresponding to the energy storage converter. Further, the peripheral circuit where the DC contactor is located also includes a circuit resistor and a circuit capacitor, the first end of the circuit resistor is connected to the drain of the field effect tube, and the second end of the circuit resistor is respectively connected to the negative terminal DC- of the battery pack and the negative access terminal DC_IN- of the power board; further, the first end of the circuit capacitor is connected to the first end of the circuit resistor, and the second end of the circuit capacitor is connected to the second end of the circuit resistor.
[0029] Further, the field effect tube is used to be controlled to be in an on state or an off state. Here, the gate of the field effect tube can be connected to a remote host computer. When the field effect tube needs to be turned on, the relevant staff can control the host computer to send a voltage to the gate of the field effect tube to turn on the field effect tube. When the field effect tube needs to be turned off, the voltage can be stopped from being sent to the gate of the field effect tube to turn off the field effect tube.
[0030] Here, according to the characteristics of the field effect tube, when the field effect tube is converted from the off state to the on state, the field effect tube is not completely turned on instantly (that is, the current flowing through the field effect tube will not change suddenly), but a relatively slow conduction process, and the current flowing through the field effect tube will gradually increase until it is fully turned on and in a stable on state. Therefore, before the DC contactor needs to be closed, the field effect tube can be controlled to be turned on to eliminate the voltage difference at both ends of the DC contactor, so that the DC contactor will not generate a large impact current at the moment of closing, thereby ensuring the operating stability of the DC contactor.
[0031] The protection circuit of a DC contactor proposed in the embodiment of the utility model can first transmit voltage to the gate of the field effect tube before the DC contactor needs to be closed to turn on the field effect tube. By using the principle of slow conduction of the field effect tube, the current flowing through the field effect tube will gradually increase and finally reach a stable state, so as to eliminate the voltage difference at both ends of the DC contactor, so as to completely avoid the situation that the DC contactor generates an impact current at the moment of closing. At the same time, a current-limiting resistor is connected in series with the field effect tube to prevent large current from damaging components such as the field effect tube and the battery pack. Further, after the voltage difference at both ends of the DC contactor is eliminated, the DC contactor can be closed. At this time, because of the existence of the current-limiting resistor, the current will pass through the DC contactor and interact between the battery pack corresponding to the energy storage converter and the power board at the rear end of the energy storage converter to realize the function of the DC contactor. The technical solution disclosed in the present application can eliminate the voltage difference at both ends of the DC contactor before the DC contactor is closed, improve the protection ability of the DC contactor against the impact current, and thus improve the operation stability of the DC contactor and the energy storage converter.
[0032] 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.
[0033] Furthermore, the control end of the switch controller is connected to the gate of the field effect tube, and is used to control the field effect tube to be in an on state or an off state. Here, when the field effect tube needs to be turned on, the relevant operator can control the switch controller to send a voltage to the gate of the field effect tube, and the voltage value of the voltage can be gradually increased; conversely, when the field effect tube needs to be turned off, the relevant operator can control the switch controller to stop sending voltage to the gate of the field effect tube. In the embodiment provided by the present application, the switch controller can control the on and off of the field effect tube, thereby improving the operability of the protection circuit of the DC contactor.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] In one embodiment, Figure 3As 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 conduction or disconnection of the field effect tube through the host computer, thereby improving the operational convenience of the protection circuit of the DC contactor.
[0039] 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.
[0040] 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.
[0041] The embodiments provided in the present application can control the closing and opening of the field effect tube and the DC contactor based on the switch control circuit. In the actual working process, before the DC contactor needs to be closed, the field effect tube can be controlled to be turned on first. When the voltage difference between the two ends of the DC contactor is eliminated, the DC contactor can be controlled to be closed, thereby improving the operability of the protection circuit of the DC contactor.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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.
[0046] 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.
[0047] 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.
[0048] In one embodiment, Figure 5 As shown, the protection circuit of the DC contactor also includes an alarm device; the alarm device here can be a buzzer or a flashlight. The alarm device can be set in a relevant control room. Furthermore, the alarm output end of the switch controller is connected to the controlled end of the alarm device, which is used to control the alarm device to issue an alarm prompt message. The embodiment provided by the present application enables the switch controller to control the alarm device to issue an alarm prompt message as soon as it recognizes that there is an abnormality in the circuit, so as to remind relevant staff to check and deal with the abnormal situation.
[0049] It should be noted that the internal circuit connection mode of the switch controller, the first voltage sensor, the second voltage sensor and the alarm device 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.
[0050] On the other hand, an embodiment of the present invention provides an energy storage converter, including the protection circuit of the DC contactor as described above.
[0051] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.
Claims
1. A protection circuit for a DC contactor, used for protecting a DC contactor in an energy storage converter from impact current, characterized in that: The protection circuit of the DC contactor includes a current limiting resistor and a field effect transistor, wherein the field effect transistor is used to be controlled to be in an on state or an off state; The first end of the current limiting resistor is connected to the first end of the DC contactor, the second end of the current limiting resistor is connected to the source of the field effect transistor, and the drain of the field effect transistor is connected to the second end of the DC contactor.
2. The protection circuit of the DC contactor according to claim 1, characterized in that: The field effect transistor is an N-channel field effect transistor.
3. The protection circuit of the DC contactor according to claim 1, characterized in that: The protection circuit of the DC contactor also includes a switch controller; The control end of the switch controller is connected to the gate of the field effect tube and is used to control the field effect tube to be in an on state or an off state.
4. The protection circuit of the DC contactor according to claim 3, characterized in that: The protection circuit of the DC contactor 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.
5. The protection circuit of the DC contactor according to claim 3, 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.
6. The protection circuit of the DC contactor according to claim 3, characterized in that: 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; 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.
7. The protection circuit of the DC contactor according to claim 6, characterized in that: 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; 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.
8. The protection circuit of the DC contactor according to claim 4, characterized in that: The protection circuit of the DC contactor also includes an alarm device; The alarm output terminal of the switch controller is connected to the controlled terminal of the alarm device, and is used to control the alarm device to send out alarm prompt information.
9. The protection circuit of the DC contactor according to claim 8, characterized in that: The alarm device is a buzzer or a flashing light.
10. An energy storage converter, characterized in that: A protection circuit comprising a DC contactor as claimed in any one of claims 1 to 9.