CN215733439U

CN215733439U - Electric fire-proof current-limiting protector

Info

Publication number: CN215733439U
Application number: CN202122267211.XU
Authority: CN
Inventors: 徐胜; 王剑国; 黄晓铭
Original assignee: Changshu Switchgear Manufacturing Co Ltd
Current assignee: Changshu Switchgear Manufacturing Co Ltd
Priority date: 2021-09-18
Filing date: 2021-09-18
Publication date: 2022-02-01
Anticipated expiration: 2031-09-18

Abstract

The utility model discloses an electric fireproof current-limiting protector which comprises a solid-state electronic switch, a circuit board and a radiator, wherein the solid-state electronic switch is composed of at least one pair of power semiconductor controllable switches in anti-series connection, the radiator is made of a conductive material, Tab pins of all the power semiconductor controllable switches in the solid-state electronic switch are tightly attached to the radiator, two power semiconductor controllable switches in the pair are in anti-series connection through the respective Tab pins and the radiator, the other pins of all the power semiconductor controllable switches in the solid-state electronic switch are bent back to the radiator, the bent pins extend out of the back of the power semiconductor controllable switches, and the circuit board is electrically connected with the other pins of all the power semiconductor controllable switches in the solid-state electronic switch. The utility model can effectively improve the heat dissipation of the solid-state electronic switch, thereby realizing larger on-off current by fewer devices, and being beneficial to miniaturization design and cost reduction.

Description

Electric fire-proof current-limiting protector

Technical Field

The utility model relates to an electric fireproof current-limiting protector.

Background

In 2019, 23.3 thousands of fires are reported in China, 1335 people are killed, 837 people are injured, and the direct property loss is 36.12 hundred million yuan. It is worth noting that the occupation of electrical fires in residential fires is high, and 52% of the fires with found causes are caused by electrical causes, especially fires caused by various household appliances, electric vehicles, electric lines and the like are more and more prominent.

The traditional mechanical circuit breaker adopts mechanical contacts to break the fault current of a main loop, when short-circuit fault occurs, the protection action completion time is about ten milliseconds, the short-circuit current is suddenly increased to thousands of amperes or even tens of kiloamperes within the short-circuit duration, and a large amount of electric arc sparks are generated, which are all adverse factors of electric fire protection.

The novel electric fire-proof current-limiting protector is a device which adopts a solid electronic switch as a breaking main loop fault current, and when a short-circuit fault occurs, the protector can quickly limit the short-circuit current at microsecond speed and realize non-arc breaking, thereby obviously reducing electric fire accidents and ensuring the safety of personnel and property in use places.

The core component of the electric fireproof current-limiting protector is a solid electronic switch, which usually adopts power semiconductor controllable switches such as IGBT and MOSFET, and the characteristics of the device directly restrict the current-carrying capacity and conduction loss of the current-limiting protector. The conduction loss power of the IGBT is the conduction voltage drop multiplied by the current-carrying capacity, the conduction voltage drop is not less than 0.7V, and although the current-carrying capacity is improved by connecting a plurality of IGBTs in parallel, the conduction voltage drop is unchanged, so that the conduction loss power is also increased. The conduction loss power of the MOSFETs is the square of the conduction resistance multiplied by the current-carrying capacity, the multiple MOSFETs are connected in parallel, the current-carrying capacity can be improved, meanwhile, the total conduction resistance is reduced, and therefore the conduction loss power can be adjusted. The existing current-limiting protector mainly uses MOSFETs based on the performance requirement of low conduction loss power, but a single MOSFET does not have the capability of turning off alternating current, and must be used in an anti-series combination in the form of drain-source-drain (D-S-D) and source-drain-source (S-D-S), and the topological structures thereof are respectively shown in fig. 2 and fig. 3. The current-carrying capacity of the current-limiting protector product is less than or equal TO 63A, a plug-in packaged MOSFET is usually selected, and a heat dissipation path of the current-limiting protector product is analyzed by taking a TO-220 package as an example, as shown in fig. 1: 1. heat is sequentially transferred from the silicon wafer to the copper substrate in a heat conduction mode, then transferred to the radiator, and finally transferred to the air in a heat convection mode; 2. heat is transferred from the silicon chip to the shell in a heat conduction mode, and the shell is transferred to air in a heat convection mode; 3. heat is transferred from the silicon chip to the pins in a heat conduction mode and then transferred to the circuit board, and finally the circuit board is transferred to air in a heat convection mode. In the 3 paths, the heat dissipation capability of the path 1 is the highest, and the Tab pin of the MOSFET, that is, the copper substrate, is required to be tightly attached to the heat sink for the MOSFET to achieve the best heat dissipation effect.

As shown in fig. 2, when the solid-state electronic switch uses a drain-source-drain (D-S-D) MOSFET anti-series topology, in the off state, the potential of the head-end drain D1 is equal to L, and the potential of the tail-end drain D2 is equal to N. The Tab pin in the MOSFET is connected with the drain D, the Tab pin needs to be tightly attached to a radiator in consideration of the heat dissipation effect, the potential of the radiator is equal to that of the drain D, and the problem of L/N insulation needs to be considered during heat dissipation design. The existing scheme 1: the MOSFETs at the head end and the tail end respectively use a group of radiators, and the two groups of radiators need to be designed with insulating gaps or separated by using insulating materials and independently designed with mounting and fixing structures, so that the miniaturization design is difficult. Existing scheme 2: the MOSFETs at the head end and the tail end use a heat dissipation device, and an insulating material must be filled between the Tab pin and the heat dissipation device, so that the thermal resistance of the insulating material is increased between the Tab pin and the heat dissipation device, the heat dissipation of the MOSFETs is not facilitated, and the current-carrying capacity of the MOSFETs cannot be fully exerted; solid state electronic switches can be damaged if the insulating material fails. The MOSFET mounting of

prior art schemes

1 and 2 is shown in fig. 1: the MOSFET is vertically welded on the circuit board, the left surface of the radiator is tightly attached to the circuit board, and other devices cannot be placed in the projection area occupied by the radiator on the circuit board.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the utility model is to overcome the defects of the prior art and provide an electric fireproof current limiting protector, and the heat dissipation of a solid-state electronic switch can be effectively improved by adopting a novel solid-state electronic switch installation form, so that larger on-off current can be realized by fewer devices, the miniaturization design is facilitated, and the cost is reduced.

The utility model specifically adopts the following technical scheme to solve the technical problems:

the utility model provides an electric fire prevention current-limiting type protector, includes solid-state electronic switch, circuit board and a radiator, solid-state electronic switch comprises at least a pair of anti-series connection's power semiconductor controllable switch pair, the radiator comprises conducting material, all power semiconductor controllable switches's in the solid-state electronic switch Tab pin is hugged closely and is fixed in on the radiator, two power semiconductor controllable switches in the pair of power semiconductor controllable switch through respective Tab pin and the anti-series connection's of radiator realization electricity is connected, all other pins of all power semiconductor controllable switches in the solid-state electronic switch are all buckled to the radiator and the back of buckling is stretched out power semiconductor controllable switch's back, the circuit board with all other pins of all power semiconductor controllable switches in the solid-state electronic switch are connected electrically.

Preferably, the power semiconductor controllable switch is an IGBT, in anti-series form emitter-collector-emitter.

Preferably, the power semiconductor controllable switch is a MOSFET, in anti-series form source-drain-source.

Preferably, at least a 3mm gap is left between the circuit board and the back surface of the power semiconductor controllable switch.

Further preferably, an electronic component is disposed in the gap.

Preferably, the solid-state electronic switch is composed of a plurality of pairs of power semiconductor controllable switches connected in anti-series, and the pairs of power semiconductor controllable switches are connected in parallel with each other.

Preferably, Tab pins of all power semiconductor controllable switches in the solid-state electronic switch are tightly fixed on the heat sink by means of screw fastening or crimping of a crimping plate.

Preferably, the heat sink is composed of a metal material.

Preferably, conductive adhesive is coated between Tab pins of all power semiconductor controllable switches in the solid-state electronic switch and the heat sink.

Preferably, the circuit board is electrically connected with the rest pin diagrams of all the power semiconductor controllable switches in the solid-state electronic switch by means of welding.

Compared with the prior art, the utility model has the following beneficial effects:

compared with the prior art that two groups of mutually insulated radiators are used, the radiator mounting structure is simple in design, more beneficial to miniaturization and lower in implementation cost;

in the solid-state electronic switch, Tab pins of all power semiconductor controllable switches are directly and tightly attached to the radiator, so that the whole path has small thermal resistance and strong heat dissipation capability, compared with the prior art, the current carrying capability of a device can be better exerted, fewer devices are used, larger current is switched on and off, and the solid-state electronic switch is beneficial to miniaturization design and cost reduction;

in the mounting structure, the circuit board and the back surface of the power semiconductor controllable switch are arranged in parallel basically, a gap is reserved between the circuit board and the back surface of the power semiconductor controllable switch, electronic components can be arranged in the projection area of the circuit board, the utilization rate of the circuit board is high, the size of the circuit board is reduced, and further the miniaturization design and the cost reduction are facilitated.

Drawings

Fig. 1 is a schematic view of a mounting structure and a heat dissipation path of a solid-state electronic switch in a conventional electrical fire-proof current-limiting protector;

FIG. 2 is a diagram of a MOSFET anti-series topology of a D-S-S-D structure;

FIG. 3 is a diagram of a MOSFET anti-series topology of an S-D-D-S structure;

FIG. 4 is a schematic diagram of a MOSFET structure of a solid state electronic switch in an exemplary embodiment;

FIG. 5 is a schematic view of an exemplary embodiment of a solid state electronic switch and heat sink mounting arrangement;

fig. 6 and 7 are schematic views of mounting structures of the solid-state electronic switch, the heat sink and the circuit board from different viewing angles in the specific embodiment.

The reference numerals in the figures are specified below:

1. MOSFET, 10, Tab pin, 11, other pins, 2, radiator, 3 and circuit board.

Detailed Description

Aiming at the defects of the prior art, the utility model adopts a novel solid-state electronic switch mounting structure, one conductive radiator is tightly attached to Tab pins of all power semiconductor controllable switches in the solid-state electronic switch, the radiator is used as a part of a current path of the solid-state electronic switch, and the rest pins of all the power semiconductor controllable switches are bent and then are electrically connected with a circuit board which is basically arranged in parallel, so that the heat dissipation of the solid-state electronic switch is effectively improved, more on-off current can be realized by fewer devices, the miniaturization design is facilitated, and the cost is reduced.

The utility model provides an electric fire-proof current-limiting protector, which comprises a solid electronic switch, a circuit board and a radiator, the solid-state electronic switch is composed of at least one pair of power semiconductor controllable switches connected in anti-series, the radiator is made of conductive material, the Tab pins of all power semiconductor controllable switches in the solid-state electronic switch are tightly fixed on the heat radiator, the two power semiconductor controllable switches of the pair of power semiconductor controllable switches are electrically connected in anti-series through the respective Tab pins and the heat sink, the rest pins of all the power semiconductor controllable switches in the solid-state electronic switch are bent back to the radiator, and the bent pins extend out of the back of the power semiconductor controllable switches, and the circuit board is electrically connected with the rest pins of all the power semiconductor controllable switches in the solid-state electronic switch.

The power semiconductor controllable switch can adopt the existing GTO, IGCT, MOSFET, IGBT, GTR, VMOS and the like, and preferably, the power semiconductor controllable switch is IGBT and is in an anti-series form of an emitter-collector-emitter; alternatively, the power semiconductor controllable switch is a MOSFET, and the anti-series form is source-drain-source.

Preferably, at least a 3mm gap is left between the circuit board and the back surface of the power semiconductor controllable switch; further, an electronic component can be arranged in the gap, so that the space utilization rate is further improved, and the miniaturization of the protector is facilitated.

In order to effectively improve the current-carrying capacity of the device, the solid-state electronic switch is preferably composed of a plurality of pairs of power semiconductor controllable switches which are connected in series in an anti-reverse manner, and the plurality of pairs of power semiconductor controllable switches are connected in parallel with each other.

Tab pins of all power semiconductor controllable switches in the solid-state electronic switch can be tightly attached and fixed with a radiator by adopting various conventional modes; preferably, Tab pins of all power semiconductor controllable switches in the solid-state electronic switch are tightly fixed on the heat sink by means of screw fastening or crimping of a crimping plate. In order to make the two have reliable electrical connection while fitting more closely, conductive adhesive can be further coated between Tab pins of all power semiconductor controllable switches in the solid-state electronic switch and the heat sink.

The heat sink can be made of various feasible heat conducting materials with electric conductivity; preferably, the heat sink is composed of a metal material.

For the public understanding, the technical scheme of the utility model is further explained in detail by a specific embodiment and the accompanying drawings:

as shown in fig. 4, the power semiconductor controllable switch used in the solid-state electronic switch of the present embodiment is a TO-220 package MOSFET1, and as shown in fig. 4, the remaining pins 11 of the MOSFET1 except for the Tab pin 10 are bent and shaped toward the back (the surface close TO the Tab pin is the front surface of the MOSFET, and the opposite surface is the back surface).

As shown in fig. 5, the solid-state electronic switch in this embodiment is composed of 6 MOSFETs 1 with bent and shaped pins, and is divided into three groups, wherein two MOSFETs 1 in each group are connected in anti-series in a source-drain-source (S-D-S) manner to form a MOSFET pair, and the three groups of MOSFET pairs are connected in parallel. As shown in fig. 5, three sets of MOSFET pairs are directly placed on the surface of the aluminum heat spreader 2, and fastened to the heat spreader 2 by screws passing through the Tab pin holes, so that the Tab pin of each MOSFET1 is tightly attached to the heat spreader 2 to achieve a reliable electrical connection, i.e., the drain D is reliably electrically connected, and the heat spreader 2 is used as a part of the current path of the solid-state electronic switch.

As shown in fig. 6 and 7, the wiring board 3 is mounted above the back surface of the MOSFET1, a spacer is placed between the wiring board and the surface of the heat sink 2 so that the back surface of the MOSFET1 is spaced from the wiring board 3 by at least 3mm, and the rest of the pins 11 of the MOSFET1 are soldered to the wiring board 3. Because a clearance of at least 3mm is reserved between the back surface of the MOSFET1 and the circuit board 3, the MOSFET can be used for placing electronic components, and the utilization rate of the circuit board 3 is improved.

In the above technical solution, the heat generated by the MOSFET1 is sequentially transferred from the silicon chip to the Tab pin 10 and then to the heat sink 3 in a heat conduction manner, and finally the heat sink 3 is transferred to the air in a heat convection manner, so that the heat dissipation capability is good.

Claims

1. An electric fireproof current-limiting protector comprises a solid electronic switch, a circuit board and a radiator, the solid-state electronic switch is composed of at least one pair of anti-series connected power semiconductor controllable switches, characterized in that the heat sink is made of conductive material, Tab pins of all power semiconductor controllable switches in the solid-state electronic switch are tightly fixed on the heat sink, the two power semiconductor controllable switches of the pair of power semiconductor controllable switches are electrically connected in anti-series through the respective Tab pins and the heat sink, the rest pins of all the power semiconductor controllable switches in the solid-state electronic switch are bent back to the radiator, and the bent pins extend out of the back of the power semiconductor controllable switches, and the circuit board is electrically connected with the rest pins of all the power semiconductor controllable switches in the solid-state electronic switch.

2. An electrical fire-protection current-limiting protector as claimed in claim 1 wherein the power semiconductor controllable switch is an IGBT in anti-series form emitter-collector-emitter.

3. An electrical fire protection current limiting protector as claimed in claim 1 wherein the power semiconductor controllable switch is a MOSFET in anti-series form source-drain-source.

4. An electrical fire protection current limiting protector as claimed in claim 1 wherein there is at least a 3mm gap between the circuit board and the back of the power semiconductor controllable switch.

5. An electrical fire protection current limiting protector as defined in claim 4 wherein electronic components are disposed in said gap.

6. An electrical fire protection current limiting protector as claimed in claim 1 wherein the solid state electronic switch is comprised of a plurality of pairs of power semiconductor controllable switches in anti-series connection, the pairs of power semiconductor controllable switches being connected in parallel with each other.

7. An electrical fire-protection current-limiting protector as claimed in claim 1, wherein Tab pins of all power semiconductor controllable switches in the solid state electronic switch are tightly fixed to the heat sink by means of screw fastening or crimping with a crimping plate.

8. An electrical fire protection current limiting protector as defined in claim 1 wherein said heat sink is constructed of a metallic material.

9. An electrical fire-protection current-limiting protector as claimed in claim 1, wherein conductive glue is coated between Tab pins of all power semiconductor controllable switches in the solid state electronic switch and the heat sink.

10. An electrical fire protection current limiting protector as defined in claim 1 wherein said circuit board is electrically connected by soldering to the remaining pin patterns of all power semiconductor controllable switches in said solid state electronic switch.