CN115085161A - Direct-current power supply protection circuit and direct-current circuit breaker - Google Patents
Direct-current power supply protection circuit and direct-current circuit breaker Download PDFInfo
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- CN115085161A CN115085161A CN202210768488.7A CN202210768488A CN115085161A CN 115085161 A CN115085161 A CN 115085161A CN 202210768488 A CN202210768488 A CN 202210768488A CN 115085161 A CN115085161 A CN 115085161A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- Emergency Protection Circuit Devices (AREA)
- Protection Of Static Devices (AREA)
Abstract
The application provides a DC power supply protection circuit and direct current breaker, the circuit includes: a main loop unit and a commutation loop unit; the main loop unit comprises a first switch component and a first inductor and is used for transmitting a direct current signal in a normal working state, and the current conversion loop unit comprises a second switch component, a second inductor and a first capacitor and is used for transferring fault current flowing through the main loop unit in a short-circuit fault state; the first end of the first switch component is used as a direct-current power supply input end, the second end of the first switch component is connected with the first end of the first inductor, and the second end of the first inductor is connected with a load; the first end of the second switch component is connected with the first end of the first switch component, and the second end of the second switch component is respectively connected with the first end of the second inductor and the second end of the first inductor; the second end of the second inductor is connected with the first end of the first capacitor; the second end of the first capacitor is connected with the second end of the first switch component. To reliably and quickly break the fault current.
Description
Technical Field
The application relates to the technical field of electronics, especially, relate to a direct current power supply protection circuit and direct current circuit breaker.
Background
In recent years, with the rapid development of renewable new energy sources, the direct current micro-grid system has gained wide attention and attention with unique advantages, and with the continuous maturation of high-power electronic technology, the advantages of the direct current micro-grid system in the aspects of large capacity and long-distance transmission, such as economy, stability and flexibility, are increasingly prominent. Different from an alternating current system, the direct current transmission does not have a natural zero crossing point, and when a fault occurs, a special method is needed to manufacture the zero crossing point so as to extinguish a switching arc to complete fault current breaking. On the other hand, because the direct current short-circuit current rises fast and has a high peak value, the breaking task must be completed within a few milliseconds, and the protection requirement of the direct current power system for current limiting and breaking can be met. Therefore, the dc power protection circuit or the dc circuit breaker has a certain difficulty in rapidly and reliably interrupting the fault current.
Disclosure of Invention
The present application is directed to solving, at least to some extent, one of the technical problems in the related art.
To this end, a first object of the present application is to provide a dc power supply protection circuit to promptly and reliably cut off a fault current.
A second object of the present application is to propose a direct current circuit breaker.
In order to achieve the above object, an embodiment of a first aspect of the present application provides a dc power protection circuit, where the dc power protection circuit is disposed in a dc circuit breaker, and the dc power protection circuit includes: a main loop unit and a commutation loop unit; the main loop unit comprises a first switch component and a first inductor, and the commutation loop unit comprises a second switch component, a second inductor and a first capacitor; a first end of the first switch component is used as a direct-current power supply input end, a second end of the first switch component is connected with a first end of the first inductor, and a second end of the first inductor is connected with a load; a first end of the second switch assembly is connected with a first end of the first switch assembly, and a second end of the second switch assembly is respectively connected with a first end of the second inductor and a second end of the first inductor; the second end of the second inductor is connected with the first end of the first capacitor; a second end of the first capacitor is connected with a second end of the first switch component; the main loop unit is used for transmitting a direct current signal in a normal working state; the commutation loop unit is used for transferring fault current flowing through the main loop unit under a short-circuit fault state.
According to an embodiment of the present application, the dc power protection circuit further includes: a control unit and a fault detection unit; the fault detection unit is used for detecting fault information; the control unit is used for: in response to the existence of the short-circuit fault, controlling the first switch component to disconnect the path of the main loop unit and controlling the second switch component to connect the path of the commutation loop unit; and in response to the short-circuit fault not existing, controlling the first switch component to connect the path of the main loop unit, and controlling the second switch component to disconnect the path of the commutation loop unit.
According to one embodiment of the present application, the second switching component comprises a power semiconductor switch and a first diode; the collector of the power semiconductor switch is connected with the negative electrode of the first diode, and the emitter of the power semiconductor switch is connected with the positive electrode of the first diode.
According to an embodiment of the present application, the dc power protection circuit further includes: a buffer circuit unit; the first end of the buffer loop unit is connected with the first end of the second switch component, and the second end of the buffer loop unit is connected with the second end of the second switch component.
According to one embodiment of the present application, the snubber circuit unit includes a resistor, a second diode, and a second capacitor.
According to an embodiment of the present application, the dc power protection unit further includes: an overvoltage protection unit; the first end of the overvoltage protection unit is connected with the first end of the second switch component, and the second end of the overvoltage protection unit is connected with the second end of the second switch component.
According to an embodiment of the application, the overvoltage protection unit comprises a zinc oxide arrester.
According to an embodiment of the application, the power semiconductor switch is an insulated gate bipolar transistor.
According to an embodiment of the application, the first capacitor and the second capacitor are pre-charge capacitors, and the first switch component is a mechanical switch.
To achieve the above object, an embodiment of a second aspect of the present application provides a dc circuit breaker, including: the dc power protection circuit according to the embodiment of the first aspect of the present application.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.
Drawings
The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a DC power supply protection circuit according to one embodiment of the present application;
FIG. 2 is a schematic diagram of a DC power protection circuit according to another embodiment of the present application;
FIG. 3 is a schematic diagram of a DC power supply protection circuit according to another embodiment of the present application;
fig. 4 is a schematic structural diagram of a dc circuit breaker according to an embodiment of the present application.
Detailed Description
Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.
The dc power protection circuit and the dc circuit breaker according to the embodiments of the present application are described below with reference to the drawings.
Fig. 1 is a schematic structural diagram of a dc power protection circuit according to an embodiment of the present application.
It should be noted that the dc power protection circuit according to the embodiment of the present application may be disposed in a dc circuit breaker.
As shown in fig. 1, the dc power protection circuit 1 according to the embodiment of the present application may specifically include: the main circuit unit 10 includes a first switch component U1 and a first inductor L1, and the commutation circuit unit 11 includes a second switch component U2, a second inductor L2 and a first capacitor C1.
A first end of the first switch module U1 is used as a dc power input end, a second end of the first switch module U1 is connected to a first end of a first inductor L1, and a second end of the first inductor L1 is connected to a load; a first terminal of the second switch assembly U2 is connected to a first terminal of the first switch assembly U1, and a second terminal of the second switch assembly U2 is connected to a first terminal of the second inductor L2 and a second terminal of the first inductor L1, respectively; a second end of the second inductor L2 is connected to a first end of the first capacitor C1; a second terminal of the first capacitor C1 is connected to a second terminal of the first switch assembly U1.
The embodiment of the application can be applied to a direct-current micro-grid protection system, a direct-current generator set can be regarded as a direct-current power supply, fault current is divided when a short-circuit fault occurs, and the main circuit unit 11 is used as a normal channel in the normal working state of the direct-current micro-grid and is used for transmitting direct-current signals in the normal working state of the direct-current micro-grid. The commutation circuit unit 11 is configured to transfer a fault current when a short-circuit fault occurs, and transfer the fault current in the main circuit unit to the commutation circuit unit.
In some embodiments, the first capacitor is a pre-charge capacitor, and the pre-charge capacitor is charged while the dc load is supplied with power through the main loop unit under a normal operation state of the dc micro-grid.
For example, the direct current flows from the left side of the direct current protection circuit to the right direct current load after flowing through the first switch assembly and the first inductor; at the moment, a passage of the commutation loop unit is in a disconnected state, no current flows through a branch circuit formed by serially connecting a first capacitor and a second inductor in the commutation loop unit, and the first capacitor is charged through a direct-current micro-grid system power supply.
In response to the occurrence of a short-circuit fault on the right side of the direct-current power supply protection circuit, the first switch component disconnects the passage of the main loop unit, and the second switch component connects the passage of the commutation loop unit. Since the inductor current cannot change abruptly, the current flowing through the first inductor does not change abruptly before and after the instant of the fault. At the moment, the connected commutation loop unit provides transient fault current through the pre-charging capacitor (i.e. the first capacitor C1), the first capacitor current Ic1 rises rapidly while the first inductor current IL1 remains constant, and the current flowing through the first switch assembly decreases rapidly, i.e. part of the current flowing through the first switch assembly is diverted to flow into the commutation loop unit. When the current Ic1 of the first capacitor reaches the current IL1 of the first inductor, the current of the branch where the first switching element is located will flow in the reverse direction to the current of the branch where the second switching element is located as Ic1 continues to rise. The first capacitor is then resonated by the first switching element, the second switching element, the fault equivalent resistor and the second inductor, during which the switching current of the first switching element will periodically change direction, producing a series of current zero-crossings. During the opening of the first switching component, the switching arc is finally extinguished at the current zero crossing of the oscillation process. When the first switch component completely extinguishes the electric arc at the current zero crossing point and realizes true disconnection, the fault current of the main circuit unit can be considered to be successfully disconnected, and then the second switch component can disconnect the passage of the commutation circuit unit.
Therefore, fault current can be quickly disconnected, and reliable protection of the direct current micro-grid can be realized.
On the basis of the above embodiment, as shown in fig. 2, the dc power protection circuit 1 may further include: a control unit 12 and a failure detection unit 13;
the fault detection unit 13 is configured to detect fault information of a system or a circuit where the dc power protection circuit is located, for example, perform fault detection on the main circuit unit.
The control unit 12 is configured to receive the fault information from the fault detection unit, determine whether a short-circuit fault exists according to the fault information, control the first switch assembly U1 to disconnect the path of the main circuit unit 10 in response to the short-circuit fault, and control the second switch assembly U2 to connect the path of the commutation circuit unit 11; in response to the absence of a short circuit fault, the first switch assembly U1 is controlled to open the path of the main circuit unit 11 and the second switch assembly U2 is controlled to open the path of the commutation circuit unit 11.
As shown in fig. 3, the second switch assembly U2 includes a power semiconductor switch Q1 and a first diode D1, wherein the power semiconductor switch Q1 may be an insulated gate bipolar transistor IGBT;
wherein, the first diode D1 is connected in anti-parallel to the power semiconductor switch Q1: the collector of the power semiconductor switch Q1 is connected to the cathode of the first diode D1, and the emitter of the power semiconductor switch Q1 is connected to the anode of the first diode D1. In addition, the gate of the power semiconductor switch Q1 may be used to trigger the power semiconductor switch Q1 to turn on according to a signal sent by the control unit.
In some embodiments, the first switch component U1 may be a mechanical switch CB, and the control unit sends a control opening signal to the mechanical switch CB to control the mechanical switch CB to open when a fault occurs.
For example, when a fault occurs in the dc microgrid, the fault detection unit detects fault information and transmits the fault information to the control unit, the control unit sends a signal to control the mechanical switch to be turned on and off, and sends a trigger signal to control the power semiconductor switch to be turned on, and the fault current is transferred from the main circuit unit to the commutation circuit unit, so that the mechanical switch is really turned on and off in a state of zero current and small voltage, the pre-charge voltage of the first capacitor can effectively limit the short-circuit fault current, after the mechanical switch contacts reach a rated open distance, the arc between the mechanical switch contacts is extinguished to break the fault current of the main circuit unit, and the control unit controls the power semiconductor switch Q1 to be turned off in response to the absence of the short-circuit fault.
Further, the dc power supply protection circuit 1 may further include: a buffer circuit unit 14; a first end of the snubber circuit unit 14 is connected to a first end of the second switch assembly U2, and a second end of the snubber circuit unit 14 is connected to a second end of the second switch assembly U2.
The snubber circuit unit 14 may be formed of an RCD snubber circuit, and includes a resistor R1, a second diode D2, and a second capacitor C2, wherein the second capacitor C2 is a pre-charge capacitor.
When the direct-current micro-grid normally supplies power, the second capacitor C2 is pre-charged through the bypass resistor R1, when an electric arc between contacts of the mechanical switch is extinguished and fault current transfer is completed, the control unit controls the power semiconductor switch Q1 to be cut off, and at the moment, the second capacitor C2 discharges to reduce the rising rate of the voltage at two ends of the power semiconductor switch Q1, so that the direct-current power supply protection circuit is ensured to work in a soft switching state, and the switching loss of the power semiconductor switch Q1 is reduced. The second diode D2 can be a fast recovery diode, which can effectively reduce the voltage on the power semiconductor switch Q1 to prevent oscillation. Meanwhile, a large amount of inductive electric energy exists in the loop, and the absorption is carried out through the second capacitor C2.
In some embodiments, as shown in fig. 3, the dc power protection circuit 1 may further include: an overvoltage protection unit 15; a first terminal of the overvoltage protection unit 15 is connected to a first terminal of the second switch component U2, and a second terminal of the overvoltage protection unit 15 is connected to a second terminal of the second switch component U2.
The overvoltage protection unit 15 may comprise, among other things, a zinc oxide arrester MOA. The overvoltage arrester MOA circuit can be used for absorbing overvoltage after the power semiconductor switch Q1 is cut off after electric arcs between contacts of the mechanical switch are extinguished, fault current transfer is completed and the power semiconductor switch Q1 is cut off, and when voltage exceeds the reference voltage of the arrester MOA, the arrester MOA acts and current is transferred to the arrester MOA.
For example, in a normal operating state, a current flows through the main circuit unit with a small contact resistance, and when a fault occurs, the control unit sends a control signal to control the mechanical switch to be turned on and off, and simultaneously sends a signal to control the IGBT to be turned on, so that the fault current is transferred from the main circuit unit to the commutation circuit unit. After the current transfer is finished, the IGBT is turned off through the control signal to break the fault current, and overvoltage generated when the IGBT is turned off is absorbed and consumed by the overvoltage protection unit and the buffer circuit unit which are connected in parallel at two ends of the current conversion circuit unit, so that the fault current is quickly broken, and the direct current micro-grid is reliably protected.
Therefore, finally, the system fault current is consumed by the buffer circuit unit and the lightning arrester, and the fault is successfully cut off. And when the fault is checked and solved, the mechanical switch is switched on again, and the direct-current power grid recovers normal operation.
In summary, the dc power protection circuit of the present application combines the good static characteristics of the mechanical switch and the good dynamic performance of the power electronic device, and can rapidly and reliably cut off the fault current, thereby meeting the requirements of short on-off time, rapid operation, and small on-state loss.
In order to realize the above embodiments, the embodiments of the present application further provide a dc circuit breaker.
As shown in fig. 4, the dc circuit breaker 40 provided in the embodiment of the present application may specifically include: the dc power protection circuit 1 according to any of the embodiments described above.
To sum up, through the direct current circuit breaker that this application provided, satisfying direct current transmission system or direct current source and moving rapidly to high voltage direct current circuit breaker itself, bear the high voltage requirement on the basis, can reliably divide disconnected heavy current, the direct current circuit breaker that this application provided novel structure, circuit are simple, the circuit breaker is small, need not cooling system, can satisfy the protection demand of the little electric wire netting of direct current that distributed new forms of energy now.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means 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 application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
Claims (10)
1. A dc power protection circuit, wherein the dc power protection circuit is provided in a dc circuit breaker, the dc power protection circuit comprising: a main loop unit and a commutation loop unit;
the main loop unit comprises a first switch component and a first inductor, and the commutation loop unit comprises a second switch component, a second inductor and a first capacitor;
a first end of the first switch component is used as a direct-current power supply input end, a second end of the first switch component is connected with a first end of the first inductor, and a second end of the first inductor is connected with a load;
a first end of the second switch component is connected with a first end of the first switch component, and a second end of the second switch component is respectively connected with a first end of the second inductor and a second end of the first inductor;
the second end of the second inductor is connected with the first end of the first capacitor;
a second end of the first capacitor is connected with a second end of the first switch component;
the main loop unit is used for transmitting a direct current signal in a normal working state;
and the commutation loop unit is used for transferring fault current flowing through the main loop unit under a short-circuit fault state.
2. The dc power protection circuit according to claim 1, further comprising: a control unit and a fault detection unit;
the fault detection unit is used for detecting fault information;
the control unit is used for:
in response to the existence of the short-circuit fault, controlling the first switch component to disconnect the passage of the main loop unit and controlling the second switch component to connect the passage of the commutation loop unit;
and in response to the short-circuit fault not existing, controlling the first switch assembly to be communicated with the path of the main loop unit, and controlling the second switch assembly to be disconnected with the path of the commutation loop unit.
3. The dc power supply protection circuit of claim 2, wherein the second switching component comprises a power semiconductor switch and a first diode;
the collector of the power semiconductor switch is connected with the negative electrode of the first diode, and the emitter of the power semiconductor switch is connected with the positive electrode of the first diode.
4. The dc power protection circuit according to claim 2, further comprising: a buffer circuit unit;
the first end of the buffer loop unit is connected with the first end of the second switch component, and the second end of the buffer loop unit is connected with the second end of the second switch component.
5. The DC power protection circuit of claim 4, wherein the snubber circuit unit comprises a resistor, a second diode, and a second capacitor.
6. The dc power protection circuit according to claim 2, further comprising: an overvoltage protection unit;
the first end of the overvoltage protection unit is connected with the first end of the second switch component, and the second end of the overvoltage protection unit is connected with the second end of the second switch component.
7. The direct current power supply protection circuit according to claim 6, wherein the overvoltage protection unit includes a zinc oxide arrester.
8. The protection circuit of claim 3, wherein the power semiconductor switch is an insulated gate bipolar transistor.
9. The dc protection circuit of claim 5, wherein the first capacitor and the second capacitor are pre-charge capacitors and the first switch component is a mechanical switch.
10. A dc circuit breaker comprising a dc power protection circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210768488.7A CN115085161A (en) | 2022-07-01 | 2022-07-01 | Direct-current power supply protection circuit and direct-current circuit breaker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210768488.7A CN115085161A (en) | 2022-07-01 | 2022-07-01 | Direct-current power supply protection circuit and direct-current circuit breaker |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115085161A true CN115085161A (en) | 2022-09-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210768488.7A Pending CN115085161A (en) | 2022-07-01 | 2022-07-01 | Direct-current power supply protection circuit and direct-current circuit breaker |
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| Country | Link |
|---|---|
| CN (1) | CN115085161A (en) |
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2022
- 2022-07-01 CN CN202210768488.7A patent/CN115085161A/en active Pending
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