Passive electric heating trigger device and application thereof

Abstract

The invention provides a passive electric heating trigger device and application thereof, and relates to the technical field of circuit protection equipment, the device comprises an insulating shell, a conductor, a blade, a deformation sheet, an elastic piece and a heat transfer block; the conductor is provided with a weak part, the blade is arranged opposite to the weak part, the deformation piece is connected with one end, far away from the weak part, of the blade, the heat transfer block is arranged between the weak part and the deformation piece, and the elastic piece compresses and compresses the deformation piece; the temperature of the weak part rises due to overload current, the heat transfer block transfers heat to the deformation sheet to soften the deformation sheet, and the restoring force of the elastic piece drives the blade to move and cuts off the weak part, so that an arc voltage signal for triggering circuit protection is generated at the fracture of the weak part. The invention has the beneficial effects that the low-multiple short-circuit current can soften the deformation sheet so as to generate a trigger signal, and the problem that the low-multiple overload current cannot quickly and effectively trigger protection is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit protection equipment, and in particular to a passive electrothermal triggering device and application thereof. Background Art

[0002] With the rapid development of the new energy industry, the importance of circuit protection has become increasingly prominent. As the core device of circuit protection, fuses are indispensable in almost all electrical fields. The fuses currently used are mainly used for short-circuit protection. When a short circuit occurs, the current in the system rises rapidly, and the heat inside the fuse quickly accumulates and melts to the melting point, forming a fracture.

[0003] However, in some special occasions, it is difficult for fuses to provide effective protection. For example, in a photovoltaic system, the DC side is composed of countless photovoltaic panels. The current generated by each photovoltaic is very small. Therefore, when it fails, the fault current it generates will also be slightly different from the normal current. For example, when the normal working current is 400A, the minimum possible fault current is only 600A, which is about 1.5 times the normal current. In this case, based on its principle design and manufacturing process, it is almost difficult for the fuse to simultaneously meet the requirements of normal operation at 400A and rapid operation at 1.5 times the overload current. Therefore, it often happens in photovoltaic systems that the fuse does not operate at low multiples of overload current, or malfunctions at normal working current.

[0004] New fuses, such as intelligent powder-type fuses, mostly use sensor electronics to detect and judge fault currents. In the event of an emergency power outage or a fault, the sensor electronics cannot work normally when the power is off.

[0005] Therefore, a passive sensing device is needed to quickly detect and judge low-multiple fault currents that are very close to normal operation. Summary of the invention

[0006] In view of this, in order to solve the problem that the low multiple overload current of the fuse cannot quickly and effectively trigger the protection, an embodiment of the present invention provides a passive electrothermal triggering device and its application.

[0007] An embodiment of the present invention provides a passive electrothermal trigger device, comprising an insulating shell, and a conductor, a blade, a deformable sheet, an elastic member and a heat transfer block arranged inside the insulating shell;

[0008] The conductor is provided with a weak point, the blade is arranged opposite to the weak point, the deformable sheet is connected to the end of the blade away from the weak point, the heat transfer block is arranged between the weak point and the deformable sheet, and the elastic member compresses and presses the deformable sheet;

[0009] The overload current causes the temperature of the weak point to rise, the heat transfer block transfers heat to the deformable piece to soften the deformable piece, and the restoring force of the elastic member drives the blade to move and cut off the weak point, thereby generating an arc voltage signal at the break of the weak point for triggering circuit protection.

[0010] Furthermore, the heat transfer block is provided with a vertically penetrating movable groove, the deformable sheet is installed on the upper part of the movable groove, and the blade is arranged in the movable groove and the upper end is connected to the deformable sheet.

[0011] Furthermore, the heat transfer block comprises two contact blocks arranged opposite to each other, the movable groove is formed between the two contact blocks, and the bottom of each contact block presses the weak part located on one side of the blade.

[0012] Furthermore, a mounting groove is provided on the upper part of the heat transfer block, the deformable sheet is embedded in the mounting groove, a clamping groove is provided on the deformable sheet, a protrusion is provided on the upper end of the blade, and the protrusion is clamped into the clamping groove to fix the upper end of the blade on the deformable sheet.

[0013] Furthermore, the conductor includes a first conductor, a second conductor and a conductive sheet, one end of the first conductor and one end of the second conductor are close to form a gap, the conductive sheet is arranged at one end of the gap and its two ends are respectively connected to the first conductor and the second conductor, and the conductive sheet forms the weak point.

[0014] Furthermore, a groove is provided in the middle of the conductive sheet, and the blade is arranged opposite to the groove.

[0015] Furthermore, the groove is provided with a plurality of through holes.

[0016] Furthermore, the elastic member includes at least one spring, and the spring is arranged directly above the weak point.

[0017] Furthermore, the conductor is made of silver or copper, the heat transfer block is made of copper or aluminum, and the deformation sheet is made of PC or PA plastic.

[0018] In addition, an embodiment of the present invention further provides an application of the above passive electrothermal triggering device, which is applied to a fuse as a fault current detection device.

[0019] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0020] 1. A passive electrothermal trigger device of the present invention, an overload current formed by a low-multiple short-circuit current causes the temperature of the weak point to rise, the heat transfer block transfers heat to the deformable piece to soften the deformable piece, the restoring force of the elastic member drives the blade to move and cut off the weak point on the conductor, an arc is generated at the cut-off point of the weak point and an arc voltage signal is generated at both ends of the break of the weak point, which is used to indicate or trigger the circuit protection device to work, through the flow cross-sectional area of ​​the weak point, the heat generated by the weak point when the normal working current flows through is not enough to soften the deformable piece, but the heat generated when the overload current flows through can soften the deformable piece, so that the low-multiple short-circuit current can soften the deformable piece, thereby causing the passive electrothermal trigger device to generate a trigger signal.

[0021] 2. An application of a passive electrothermal trigger device of the present invention is to apply the passive electrothermal trigger device to a fuse as a fault current detection device. The fuse is installed in a high-voltage main circuit of various power systems. When a low-multiple overload current occurs due to a short circuit or other fault, the passive electrothermal trigger device is triggered, and quickly detects and sends out an indication signal for triggering the fuse / switch and other protective devices, thereby solving the problem in the electrical protection industry (fuse) that a low-multiple overload current cannot quickly and effectively trigger protection.

[0022] 3. The application of a passive electrothermal trigger device of the present invention, applied to a fuse, can achieve stable and reliable protection of more than 1.45 times the short-circuit current in the photovoltaic field. Compared with traditional fuses, it operates faster and more stably under low-multiple overload currents, and has lower power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an exploded view of a passive electrothermal trigger device of the present invention;

[0024] Figure 2 is a schematic diagram of a conductive sheet;

[0025] Figure 3 is a schematic diagram of a heat transfer block, a blade and a deformation sheet;

[0026] Figure 4 It is a schematic diagram of the normal operation of a passive electrothermal trigger device of the present invention;

[0027] Figure 5 It is a schematic diagram of a triggering state of a passive electrothermal triggering device of the present invention;

[0028] Figure 6 It is a schematic diagram of a passive electrothermal triggering device of the present invention applied to a fuse.

[0029] In the figure: 1, upper shell; 2, fixing plate; 3, conductive sheet; 4, heat transfer block; 5, blade; 6, deformation sheet; 7, spring; 8, first conductor; 9, second conductor; 10, fixing bolt; 11, wire; 12, perforation; 13, groove; 14, contact block; 15, movable groove; 16, mounting groove; 17, card slot; 18, bump; 100, passive electrothermal trigger device; 200, gunpowder type breaker. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the following will further describe the embodiments of the present invention in conjunction with the accompanying drawings. The following is a preferred embodiment of the present invention, which is intended to provide a basic understanding of the present invention, but is not intended to confirm the key or decisive elements of the present invention or to limit the scope of protection.

[0031] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0032] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0033] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings. At the same time, it should be understood that for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0034] It should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Please refer to Figure 1 and 6 The embodiment of the present invention provides a passive electrothermal trigger device 100 (hereinafter referred to as the passive electrothermal trigger device), which can quickly detect the fault current in the protected circuit and send an indication signal to trigger the circuit protection device. The passive electrothermal trigger device 100 mainly includes an insulating shell, and a conductor, a blade 5, a deformable sheet 6, an elastic member and a heat transfer block 4 arranged inside the insulating shell.

[0036] The conductor is provided with a weak point, the blade 5 is arranged opposite to the weak point, the deformation sheet 6 is connected to the end of the blade 5 away from the weak point, the heat transfer block 4 is arranged between the weak point and the deformation sheet 6, and the elastic member compresses and presses the deformation sheet 6.

[0037] Specifically, the insulating shell is generally made of insulating plastic for packaging and protection. The shape of the insulating shell can be flexibly set according to actual needs. For example, in this embodiment, the insulating shell is set as a cuboid, consisting of an upper shell 1 and a fixing plate 2 at the bottom.

[0038] The conductor is generally made of silver or copper with excellent conductivity, and is arranged in a straight row. The weak point is set in the middle of the conductor and arranged along the width direction of the conductor. The cross-sectional area of ​​the weak point is reduced relative to the other parts of the conductor, so that the weak point can easily generate more heat and can be cut off more easily.

[0039] like Figure 2 As shown, in this embodiment, the conductor includes a first conductor 8, a second conductor 9 and a conductive sheet 3, the first conductor 8 and the second conductor 9 are located on the same straight line, one end of the first conductor 8 and one end of the second conductor 9 are close to form a gap, and the other end of the first conductor 8 and the other end of the second conductor 9 respectively penetrate the opposite two side walls of the housing. The conductive sheet 3 is arranged at one end of the gap and the two ends are respectively connected to the first conductor 8 and the second conductor 9, and the conductive sheet 3 forms the weak point.

[0040] In some other embodiments, the conductive sheet 3 is a rectangular sheet, a groove 13 is provided in the middle of the conductive sheet 3, and the cross section of the groove 13 is trapezoidal. The blade 5 is arranged opposite to the groove 13 so that the blade 5 can accurately cut the groove 13.

[0041] Furthermore, the groove 13 is provided with a plurality of perforations 12, and the perforations 12 are arranged along the length direction of the groove 13. The perforations 12 can reduce the flow cross-sectional area of ​​the weak point, so that the weak point can generate more heat and be more easily cut off.

[0042] The deformation sheet 6 has a high hardness at room temperature, and starts to soften and deform when reaching its softening temperature. The deformation sheet 6 is generally made of a plastic material that is easily deformed by heat, such as PC (polycarbonate) or PA (polyamide) plastic.

[0043] like Figure 3As shown, the material of the heat transfer block 4 is usually selected from metals such as copper or aluminum with good thermal conductivity to conduct the heat generated at the weak point to the deformable sheet 6. Specifically, the heat transfer block 4 is provided with a vertically penetrating movable groove 15, the deformable sheet 6 is installed on the upper part of the movable groove 15, and the blade 5 is arranged in the movable groove 15 and connected to the deformable sheet 6 at the upper end.

[0044] In some embodiments, a mounting groove 16 is provided on the upper portion of the heat transfer block 4, the deformable sheet 6 is embedded in the mounting groove 16, a card slot 17 is provided on the deformable sheet 6, a protrusion 18 is provided on the upper end of the blade 5, and the protrusion 18 is inserted into the card slot 17 so that the upper end of the blade 5 is fixed on the deformable sheet 6, so that the deformable sheet 6 is stably installed on the upper portion of the movable groove 15.

[0045] In some embodiments, the heat transfer block 4 includes two contact blocks 14 arranged opposite to each other, and the movable groove 15 is formed between the two contact blocks 14. The blade 5 is just constrained in the movable groove 15 and aligned with the weak point. The two ends of the deformable sheet 6 are respectively supported on the two contact blocks 14, and the middle part is suspended. The bottom of each contact block 14 presses the part of the weak point located on one side of the blade 5 to transfer as much heat generated at the weak point as possible to the deformable sheet 6. A plurality of fixing holes are provided on the two contact blocks 14, and a fixing bolt 10 is provided at the bottom of the fixing plate 2. The fixing bolt 10 passes through the first conductor 8 and the second conductor 9 and connects the two contact blocks 14, so that the two contact blocks 14 press the conductive sheet 3.

[0046] The elastic member is fixedly arranged above the weak point, the elastic member is compressed, the lower end presses the deformable sheet 6, and is located directly above the weak point. At room temperature, the elastic member is supported and does not deform. In some embodiments, the elastic member includes at least one spring 7, and the spring 7 is arranged directly above the weak point. As described in this embodiment, the elastic member includes two springs 7, and the two springs 7 are arranged in parallel and are both arranged above the weak point, and the lower end supports and presses the deformable sheet 6.

[0047] The passive electrothermal trigger device 100 is connected to the protected circuit through the first conductor 8 and the second conductor 9 to perform current overload protection on the protected circuit.

[0048] When a low-multiple short-circuit current occurs in the protected circuit, the low-multiple short-circuit current generally refers to a short-circuit current between 1.4 times and 5 times the rated current. The overload current formed by the low-multiple short-circuit current causes the temperature of the weak point to rise, and the heat transfer block 4 transfers heat to the deformable piece 6 to soften the deformable piece 6. The restoring force of the elastic member drives the blade 5 to move and cut off the weak point, thereby generating an arc voltage signal at the fracture of the weak point for triggering circuit protection.

[0049] Specifically, Figure 4 As shown, the low multiple short-circuit current will cause the weak part to generate more heat, accumulate heat and heat up quickly, that is, the conductive sheet 3 between the first conductor 8 and the second conductor 9 will heat up quickly. The temperature of the conductive sheet 3 is difficult to reach its melting point under low multiple overload current and will not melt. For example, the conductive sheet 3 is made of silver sheet, and the melting point is about 960°C. At this time, the temperature of the conductive sheet 3 is not enough to melt it, and it cannot trigger the fuse. However, under low multiple overload current, the conductive sheet 3 heats up and is transferred to the deformable sheet 6 through the heat transfer block 4. When the temperature of the deformable sheet 6 reaches its thermal deformation temperature, it will begin to soften and bend. At this time, under the action of the restoring force of the elastic member, the deformable sheet 6 is deformed downward to drive the blade 5 to move downward. During the downward movement, the blade 5 will cut the groove 13 of the conductive sheet 3 to form a fracture. An arc will be generated at the fracture and an arc voltage signal will be generated at both ends of the conductive sheet 3. The voltage signal is connected through the wires 11 on both sides to form a voltage signal for indication or triggering.

[0050] like Figure 5 As shown, when a high multiple short-circuit current occurs in the protected circuit, which generally refers to a short-circuit current of more than 5 times the rated current, the conductive sheet 3 will heat up quickly and quickly reach its melting point, and the groove 13 of the conductive sheet 3 will melt to form a fracture, an arc will be generated at the fracture, and an arc voltage signal will be generated at both ends of the conductive sheet 3, which will be connected through the wires 11 on both sides to form a voltage signal for indication or triggering. Since the high multiple short-circuit current will cause the conductive sheet 3 to melt quickly at high temperature, the conductive sheet 3 will be melted before the deformable sheet 6 softens, generating an arc voltage signal to achieve faster indication or triggering under high multiple short-circuit current.

[0051] In addition, if Figure 6 As shown, an embodiment of the present invention also provides an application of the above-mentioned passive electrothermal trigger device 100, which is applied to a fuse as a fault current detection device, and the above-mentioned passive electrothermal trigger device 100 is used as a trigger component of the fuse to trigger the fuse to melt.

[0052] Specifically, as in this embodiment, the fuse includes the passive electrothermal trigger device 100 and the powder-type breaker 200, and the two ends of the conductive sheet 3 are connected to the controller of the powder-type breaker 200. When protecting the protected circuit, the passive electrothermal trigger device 100 and the powder-type breaker 200 are connected in series to the protected circuit. When a low-multiple short-circuit current and a high-multiple short-circuit current appear in the protected circuit, arc voltage signals are generated at both ends of the conductive sheet 3. After receiving the arc voltage signal, the controller controls the powder-type breaker 200 to perform disconnection, thereby disconnecting the protected circuit.

[0053] The fuse is applied to the photovoltaic system circuit to realize stable and reliable protection when a low-multiple short-circuit current of 1.45 times or more appears in the circuit. Compared with the traditional fuse, the fuse operates faster, more stably and with lower power consumption under low-multiple overload current.

[0054] Although the above-mentioned passive electrothermal trigger device 100 is applied to the fuse composed of the gunpowder type switch 200 in this embodiment, it can be understood that the above-mentioned passive electrothermal trigger device 100 can also be applied to other types of fuses, circuit protection switches and other circuit protection devices to detect fault current for the circuit protection device, thereby triggering the circuit protection device to perform protection.

[0055] In this article, the directional words such as front, back, top, and bottom involved are defined by the positions of the parts in the drawings and the positions of the parts relative to each other, just for the sake of clarity and convenience in expressing the technical solution. It should be understood that they are relative concepts and can change accordingly according to different ways of use and placement, and the use of the directional words should not limit the scope of protection claimed in this application.

[0056] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A passive electrothermal triggering device, characterized in that: It comprises an insulating shell, and a conductor, a blade, a deformable sheet, an elastic member and a heat transfer block arranged inside the insulating shell; The conductor is provided with a weak point, the blade is arranged opposite to the weak point, the deformable sheet is connected to the end of the blade away from the weak point, the heat transfer block is arranged between the weak point and the deformable sheet, and the elastic member compresses and presses the deformable sheet; The overload current causes the temperature of the weak point to rise, the heat transfer block transfers heat to the deformable piece to soften the deformable piece, and the restoring force of the elastic member drives the blade to move and cut off the weak point, thereby generating an arc voltage signal at the break of the weak point for triggering circuit protection.

2. A passive electrothermal triggering device as claimed in claim 1, characterized in that: The heat transfer block is provided with a vertically penetrating movable groove, the deformable sheet is installed on the upper part of the movable groove, and the blade is arranged in the movable groove and the upper end is connected to the deformable sheet.

3. A passive electrothermal triggering device as claimed in claim 2, characterized in that: The heat transfer block comprises two contact blocks arranged opposite to each other, the movable groove is formed between the two contact blocks, and the bottom of each contact block presses the weak part located on one side of the blade.

4. A passive electrothermal triggering device as claimed in claim 2 or 3, characterized in that: The upper part of the heat transfer block is provided with a mounting groove, the deformable sheet is embedded in the mounting groove, the deformable sheet is provided with a clamping groove, the upper end of the blade is provided with a protrusion, the protrusion is clamped into the clamping groove to fix the upper end of the blade on the deformable sheet.

5. A passive electrothermal triggering device as claimed in claim 1, characterized in that: The conductor includes a first conductor, a second conductor and a conductive sheet. One end of the first conductor and one end of the second conductor are close to form a gap. The conductive sheet is arranged at one end of the gap and its two ends are respectively connected to the first conductor and the second conductor. The conductive sheet forms the weak point.

6. A passive electrothermal triggering device as claimed in claim 5, characterized in that: A groove is provided in the middle of the conductive sheet, and the blade is arranged opposite to the groove.

7. A passive electrothermal triggering device as claimed in claim 6, characterized in that: The groove is provided with a plurality of through holes.

8. A passive electrothermal triggering device as claimed in claim 1, characterized in that: The elastic member includes at least one spring, and the spring is arranged just above the weak point.

9. A passive electrothermal triggering device as claimed in claim 1, characterized in that: The conductor is made of silver or copper, the heat transfer block is made of copper or aluminum, and the deformation sheet is made of PC or PA plastic.

10. Application of a passive electrothermal triggering device as claimed in any one of claims 1 to 9, characterized in that: Used in fuses as a fault current detection device.

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