Intelligent fuse

Abstract

The invention belongs to the field of fuses, and provides an intelligent fuse which comprises a conductor used for bearing main loop current; the fuse body is connected in the conductor in series and can be fused when the current of the main loop exceeds a preset threshold value; a first cutting unit configured to cut off the melt based on an external trigger signal; and a second cutting unit configured to cut off the conductor based on an internal trigger signal, where the internal trigger signal is a voltage signal across the melt. The intelligent fuse solves the technical problems that an intelligent fuse in the prior art is complex in structure and high in cost, and is low in cost, small in size, simple in structure and easy to operate.

Description

Technical Field

[0001] This application belongs to the field of fuses, specifically relating to an intelligent fuse. Background Technology

[0002] The statements in this section are merely to provide background information in relation to the present invention to aid in understanding the invention, and such background information does not necessarily constitute prior art.

[0003] As a protector against short circuits and overcurrents, fuses are widely used in high and low voltage power distribution systems, control systems, and electrical equipment, and are one of the most commonly used protective devices.

[0004] Currently, traditional fuses use thermal melting to disconnect circuits. They are passive fuses that achieve overcurrent protection based on the "current thermal effect," and are simple in structure, highly reliable, and low in cost. Traditional fuses can break circuits in the millisecond range in high-current breaking applications, but at low multiples of the rated current, the breaking time can be as long as hundreds of milliseconds or more.

[0005] In the fields of new energy vehicles and semiconductor protection, the protected objects are battery cells or semiconductor devices. These objects require millisecond-level interruption at low multiples of the rated current, which traditional fuses cannot meet. To address this, engineers have proposed an active fuse that, triggered by an external signal, can quickly identify faults such as overloads and short circuits and complete the interruption action within milliseconds. However, this active fuse requires more detection and drive circuitry, increasing system cost and the risk of failure. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide an intelligent fuse, comprising:

[0007] A conductor used to carry the main circuit current;

[0008] A molten element, connected in series in the conductor, capable of melting and breaking when the main circuit current exceeds a preset threshold;

[0009] A first cutting unit is configured to cut the melt based on an external trigger signal; and

[0010] The second cutting unit is configured to cut the conductor based on an internal trigger signal, wherein the internal trigger signal is a voltage signal across the melt.

[0011] According to the intelligent fuse of the present invention, preferably, the first cutting unit and the second cutting unit respectively include a cutting component, an actuating component for pushing the cutting component, and a driving interface for driving the actuating component.

[0012] According to the intelligent fuse of the present invention, preferably, the drive interface of the second cutting unit is connected to both ends of the molten metal.

[0013] The intelligent fuse according to the present invention preferably further includes a signal current limiter connected between the drive interface of the second cutting unit and the end of the fusible element.

[0014] According to the intelligent fuse of the present invention, preferably, the drive interface of the first cutting unit is configured to be connected to an external controller.

[0015] In the intelligent fuse according to the present invention, preferably, the cutting component is an insulating cutting component.

[0016] According to the intelligent fuse of the present invention, preferably, the actuating component is a pyrotechnic device.

[0017] According to the intelligent fuse of the present invention, preferably, the length of the fusible element is 1 to 10 millimeters.

[0018] The smart fuse according to the invention preferably further includes an arc extinguishing device configured to extinguish the electric arc generated when the conductor is cut.

[0019] According to the intelligent fuse of the present invention, preferably, the conductor further includes a pre-break, and the second cutting unit is configured to cut the conductor at the pre-break location.

[0020] Compared with existing technologies, the intelligent fuse of the present invention adopts internal and external dual triggering, which is highly safe, low in cost, small in size, simple in structure and easy to operate. Attached Figure Description

[0021] The embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the structure of an intelligent fuse according to an embodiment of the invention;

[0023] Figure 2 This is a schematic diagram of a bidirectional diode according to an embodiment of the invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Embodiments of the present invention provide a novel intelligent fuse with both internal and external dual triggering, which combines the thermal melting and breaking function of a conventional fuse with the rapid breaking capability of an active fuse. It is triggered by a parallel connection of an internal trigger signal and an external trigger signal. The internal trigger signal is generated by the melting arc of a conventional fuse, while the external trigger signal is a drive signal from an external controller.

[0026] See Figure 1 The schematic diagram shown is of a smart fuse according to an embodiment of the present invention, which includes a conductor 106 and a fusible element 101 connected in series within the conductor 106. In this invention, "the fusible element connected in series within the conductor" means that the fusible element is connected to the conductor at any position between the two ends of the conductor (e.g., between the first and second parts of the conductor) and is connected in series with the conductor (e.g., in series with the first and second parts of the conductor). Thus, the fusible element is directly connected in series to the main current circuit formed by the conductors, allowing all operating current in the circuit to flow through the fusible element, thereby enabling real-time monitoring of the main circuit current state and providing protection.

[0027] The smart fuse also includes a first cutting unit 1 configured to cut off the fuse element 101 based on an external trigger signal and a second cutting unit 2 configured to cut off the conductor 106 based on an internal trigger signal. The first cutting unit 1 includes a first cutting component 102, a first actuating component 103 for pushing the first cutting component 102, and a first driving interface 104 for receiving an external trigger signal to drive the first actuating component 103. The second cutting unit 2 includes a second cutting component 105, a second actuating component 110 for pushing the second cutting component 105, and a second driving interface 111 for receiving an internal trigger signal to drive the second actuating component 110. The second driving interface 111 is electrically connected to both ends of the fuse element 101 and drives the second actuating component 110 to actuate based on the voltage signal across the fuse element 101 to push the second cutting component 105. Specifically, the first terminal N1 and the second terminal N2 of the second driving interface 111 are electrically connected to the first terminal N3 and the second terminal N4 of the fuse element 101, respectively. In this invention, the second drive interface 111 acquires the voltage signals at both ends of the melt 101. It is not necessarily connected to the ends of the melt 101 itself, but can also be connected across the melt 101 to the conductor 106 near the ends of the melt 101. Therefore, the first end N3 and the second end N4 of the melt 101 can be either the two ends of the melt 101 itself or the conductors near the two ends of the melt 101 itself.

[0028] Furthermore, the smart fuse also includes an arc-extinguishing device 109, which is configured to extinguish the arc generated when the conductor 106 is cut. In embodiments of the present invention, the arc generated by the disconnection of the fusible element 101 is extinguished due to the disconnection of the conductor 106, and the arc-extinguishing device 109 is capable of extinguishing the arc generated by the disconnection of the conductor 106. Therefore, the present invention can achieve the extinguishing of all arcs using only one arc-extinguishing device.

[0029] According to an embodiment of the present invention, conductor 106 is used to carry the main circuit current, and is preferably a slender wire or a flat conductor, preferably made of copper, aluminum, gold, silver, iron, and various metal alloys. In high-current applications, copper, aluminum, or copper-clad aluminum are preferably used to reduce costs. More preferably, a pre-break 107 is provided in conductor 106 to facilitate cutting. The pre-break 107 is preferably obtained by removing a portion of material from inside conductor 106, and the cross-sectional area of ​​the pre-break 107 is smaller than the cross-sectional area of ​​conductor 106. The shape of the pre-break 107 is preferably a V-groove, a U-groove, or a combination of various groove shapes.

[0030] According to embodiments of the present invention, the melt 101 is preferably made of copper, aluminum, copper-aluminum composite, gold, silver, iron, and various metal alloys. There are two ways to disconnect the melt 101: when the main circuit current exceeds a preset threshold, the melt 101 is disconnected by thermal melting, i.e., the melt 101 heats up and undergoes a solid-liquid-gas change until it is completely disconnected. The preset threshold is usually several times the rated current, set according to user needs, and in embodiments of the present invention, it can be several to several hundred times the rated current. When the first drive interface 104 receives an external trigger signal (preferably a voltage signal or a current signal) from an external controller, it drives the first actuating component 103 to move and push the first cutting component 102 toward the melt 101 to cut it off. Regardless of the disconnection method, when the melt 101 is disconnected, a rapidly changing voltage signal is generated at its two ends. This voltage signal is provided to the second drive interface 111, thereby driving the second actuating component 110 to move and push the second cutting component 105 toward the conductor 106 to cut it off.

[0031] In some embodiments of the present invention, the length of the fuse element 101 can be set to 1-10 mm, which is much shorter than the approximately 10 cm length of the fuse element in a conventional fuse. Furthermore, under the same rated current, the cross-sectional area of ​​the fuse element 101 can be tens of times larger than that of a conventional fuse element, for example, 10 to 90 times larger. The shorter, thicker fuse element used in the embodiments of the present invention improves the fuse element's ability to withstand high currents and extends its lifespan.

[0032] In some embodiments of the present invention, the first actuating component 103 and the second actuating component 110 are both pyrotechnic devices, preferably ignition tubes or gas generators (MGGs). When they are in operation, they can generate a large amount of gas quickly when energized, and the gas jets drive the corresponding cutting components to move.

[0033] According to an embodiment of the present invention, the first cutting component 102 and the second cutting component 105 respectively cut the melt 101 and the conductor 106, so that the melt 101 or the conductor 106 changes from a conductive state to an open state. Preferably, the cutting component is an insulating cutting component to prevent the main circuit current from continuing through the cutting component after the melt 101 or the conductor 106 is cut. Preferably, the cutting component is made of an insulating material, such as PA66, PC, PBT, PPS, PEEK, or other synthetic materials.

[0034] In some embodiments of the present invention, the first cutting component 102 has a first end and a second end, the first end being close to the first actuating component 103 and the second end being close to the melt 101 for cutting. Preferably, the cross-sectional area of ​​the first end is larger than that of the second end. Because the cross-sectional area of ​​the second end is smaller, the contact area with the melt 101 during the cutting process is smaller, so a greater pressure can be obtained under the same pressure, making it easier to break the melt 101. In addition, the cross-sectional area of ​​the first end of the first cutting component 102 close to the first actuating component 103 is larger, so a greater pushing force can be obtained under the same gas pressure.

[0035] Similarly, the second cutting component 105 has a first end and a second end, the first end being close to the second actuating component 110, and the second end being close to the pre-cut opening 107 of the conductor 106 for cutting. Preferably, the cross-sectional area of ​​the first end is larger than that of the second end. Because the cross-sectional area of ​​the second end is smaller, the contact area with the conductor 106 during the cutting process is smaller, so a greater pressure can be obtained under the same pressure, making it easier to break the conductor 106. In addition, the larger cross-sectional area of ​​the first end of the second cutting component 105 near the second actuating component 110 allows for a greater pushing force under the same gas pressure.

[0036] According to an embodiment of the present invention, preferably, the second cutting unit 2 further includes a signal current limiter 108, which is used to prevent the millivolt-level voltage generated across the melt 101 when the main circuit current is normal from affecting the lifespan of the second actuating component 110. Preferably, the signal current limiter 108 is a rectifier diode, a Zener diode, a transient voltage suppressor diode (TVS diode), a resistor, etc. More preferably, the signal current limiter 108 is a bidirectional diode, such as... Figure 2The schematic diagram of the bidirectional diode shown includes a first diode D1 and a second diode D2 connected in reverse parallel, so that the operation of the signal current limiter 108 is not limited by the direction of the main circuit current. More preferably, the signal current limiter 108 is a bidirectional TVS diode, which has higher integration and better protection performance.

[0037] In another embodiment, the signal current limiter 108 is not included in the second cutting unit 2, but is a separate component disposed outside the second cutting unit 2.

[0038] According to some embodiments of the present invention, the arc-extinguishing device 109 is an air arc-extinguisher, a wire mesh arc-extinguisher, or a quartz sand arc-extinguisher, and may also be another melt connected in parallel to the break in conductor 106, for example, connected in parallel to pre-break 107. Although Figure 1 The diagram shows the arc-extinguishing device 109 connected to the conductor 106 at both ends, but this is only illustrative and not limiting. When the arc-extinguishing device 109 is an air arc-extinguisher or a wire mesh arc-extinguisher, the arc-extinguishing device 109 is not connected to the conductor 106. Therefore, the arc-extinguishing process is not affected by the main circuit current, increasing the arc-extinguishing speed and shortening the fuse breaking time. In some embodiments, the arc-extinguishing time is on the order of milliseconds, preferably 2 to 3 milliseconds. Furthermore, in the case of such air or wire mesh arc-extinguishing, the second cutting component 105 also serves to push the arc into the arc-extinguishing device 109 for arc extinguishing after cutting the conductor 106.

[0039] The inventors have creatively conceived of using an external trigger signal to cut off the molten metal and to cut off the internal overcurrent and short-circuit fuse, and using the voltage signal across the molten metal to drive the ignition tube to cut off the conductor. In embodiments of the invention, such as Figure 1 As shown, the first cutting unit 1 and the second cutting unit 2 cut the fuse 101 and the conductor 106 independently. Therefore, the breaking of the fuse 101 will not affect the first cutting unit 1, that is, it will not affect the external triggering circuit of the smart fuse. Therefore, there is no need to set an isolation transformer at the output terminal of the fuse 101 for isolation, which saves the cost and size of the smart fuse, and makes the structure simple and easy to operate.

[0040] While the present invention has been described through preferred embodiments, it is not limited to the embodiments described herein, and various changes and modifications are made without departing from the scope of the invention.

[0041] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

Claims

1. A smart fuse, comprising: A conductor used to carry the main circuit current; A molten element, connected in series in the conductor, capable of melting and breaking when the main circuit current exceeds a preset threshold; The first cutting unit is configured to cut the melt based on an external trigger signal; and The second cutting unit is configured to cut the conductor based on an internal trigger signal, wherein the internal trigger signal is a voltage signal across the melt.

2. The intelligent fuse according to claim 1, wherein, The first cutting unit and the second cutting unit each include a cutting component, an actuating component for pushing the cutting component, and a driving interface for driving the actuating component.

3. The intelligent fuse according to claim 2, wherein, The drive interface of the second cutting unit is connected to both ends of the melt.

4. The intelligent fuse according to claim 3, wherein, It also includes a signal current limiter, which is connected between the drive interface of the second cutting unit and the end of the melt.

5. The intelligent fuse according to claim 2, wherein, The drive interface of the first cutting unit is configured to connect to an external controller.

6. The intelligent fuse according to claim 2, wherein, The cutting component is an insulated cutting component.

7. The intelligent fuse according to claim 2, wherein, The actuating component is a pyrotechnic device.

8. The smart fuse according to any one of claims 1-7, wherein, The length of the melt is 1 to 10 millimeters.

9. The smart fuse according to any one of claims 1-7 further includes an arc extinguishing device configured to extinguish an electric arc generated when the conductor is cut.

10. The smart fuse according to any one of claims 1-7, wherein, The conductor also includes a pre-break, and the second cutting unit is configured to cut the conductor at the pre-break location.

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