CN114336508A

CN114336508A - Circuit protection method and device based on arc acting

Info

Publication number: CN114336508A
Application number: CN202210218341.0A
Authority: CN
Inventors: 庄逸尘; 鄢玲; 李思光; 张利; 唐有东
Original assignee: Wuhan Jingrongchao Electric Technology Co ltd
Current assignee: Wuhan Jingrongchao Electric Technology Co ltd
Priority date: 2022-03-08
Filing date: 2022-03-08
Publication date: 2022-04-12

Abstract

The technical scheme adopted by the invention is as follows: a circuit protection method and device based on arc doing work. The method comprises the following steps: when the circuit is in short circuit fault, the energy of the electric arc is used for acting to push the rod piece and disconnect the conductor connection, so that circuit breaking is realized. The device comprises an arc generator and a conductor connected in series in an electric circuit; the device also comprises a rod piece; wherein the rod is in contact with the arc generator; the rod piece is positioned between the arc generator and the electric conductor; when the circuit is in short circuit fault, the arc generator emits energy to do work, and the rod piece is pushed to move to disconnect the conductor, so that circuit breaking is realized. The invention uses the energy of the electric arc to replace initiating explosive devices to become a power source, thereby improving the overall safety.

Description

Circuit protection method and device based on arc acting

Technical Field

The invention belongs to the technical field of circuit protection, and particularly relates to a circuit protection method based on arc acting.

Background

In new energy industries, such as electric vehicles, wind power, energy storage and the like, direct current power systems are widely applied, and the protection of the direct current systems is also important. For example, in an electric automobile, if a short circuit occurs in a battery pack, combustion and even explosion can be generated, and the life safety of personnel on the automobile can be seriously threatened.

The protection method commonly used in the direct current system is a traditional fuse wire, the action principle of the traditional fuse wire is the same as that of a common fuse wire, when a short circuit occurs, the current can rise rapidly, the fuse wire is fused under the action of the heat effect of the current, and the restraint and the cut-off of the short circuit current are completed. However, as the demand of the market for the load of the dc system increases, the current condition becomes more and more severe, and the traditional fuse wire is difficult to meet the protection requirement. For example, in the protection of the current electric vehicle, when a part of high-performance vehicles run normally, rapid acceleration and deceleration frequently occur, and when the vehicles are charged with electricity, the vehicles are also charged with electricity at a super rapid speed, so that the current in the loop is maintained at a high level, and the tolerance of the fuse is extremely high. Meanwhile, the conventional fuse is required to be quickly fused when short circuit occurs. This problem is difficult to solve from the principle of the conventional fuse.

At present, a novel Fuse mainly comprising Pyro Fuse appears on the market, and main manufacturers include Eaton Bussmann, Sensata, Autoliv and the like. Compared with the traditional Fuse, a Pyro Fuse (short for Pyro) type product has better tolerance and stronger breaking capacity. Pyro-type products have started to be tested in various large car factories, including dymler, the public, tesla, etc., and it has become a future trend to use new Pyro Fuse products instead of traditional fuses.

The commonly used short-circuit protection device is a traditional fuse (fast fuse), and the major manufacturers worldwide take BUSSMANN, PEC and the like as the main parts, and the West Anzhong fuse is the main part in China. The traditional fuse wire is used as a mature short-circuit protection device and can meet the requirements under most conditions in the past. Taking the circuit on the electric automobile as an example, taking fig. 1 as an example, the power supply system is normally opened by a relay and is connected with a conventional fuse in series for protection. The operation principle of the conventional fuse is simple, the internal structure of the conventional fuse is as shown in fig. 2, and a plurality of weak points with small cross-sectional areas are arranged on a metal sheet of the fuse. When the current flows, the weak part can rapidly collect heat and be fused, and an electric arc can be generated at the fracture. The high-temperature electric arc is cooled and releases energy by ablating energy-absorbing substances (quartz sand or water glass) wrapped around, and is gradually extinguished, so that insulation is built at the fracture of the metal sheet, and the breaking of the circuit is completed.

The traditional fuse has a serious problem in use at present, taking the working condition on an electric automobile as an example, if the rated current of the fuse is 400A, the current can reach more than 600A in a short time (1-10 seconds) when the automobile is accelerated rapidly, and the fuse appears repeatedly; when the automobile is charged, particularly under a super quick charging working condition, the current in the loop can reach about 700A for a long time (10-30 minutes).

In order to ensure that the traditional fuse wire can resist the current impact in the electric car, the weak part needs to collect less heat and radiate more quickly during design. However, the conventional fuse is more difficult to blow when short-circuited. The minimum action current of a conventional fuse is at least 10 times larger than the rated current, and the action time is very long (several seconds to tens of seconds). Therefore, when a short circuit occurs and the short circuit current is smaller than the minimum operating current of the conventional fuse, the conventional fuse cannot operate and the relay cannot be opened, which may cause damage to the relay and other parts, resulting in very serious consequences.

In order to solve the dead zone of protection of the traditional Fuse wire in the small short-circuit current, each large car factory starts to try a new protection measure-Pyro Fuse. The Pyro Fuse has the function of mainly protecting the dead zone of the traditional Fuse, for example, the Autoliv of the first factory which starts to develop the Pyro Fuse also puts the Pyro Fuse into a loop when in use, as shown in fig. 3, when the Fuse is short-circuited and the traditional Fuse cannot operate, an automobile BMS (battery management system) sends a signal to the Pyro Fuse, so that the Pyro Fuse is disconnected, and the protection is completed. The principle of Pyro Fuse mainly used in the market is basically the same, and the main components of the Pyro Fuse are roughly divided into a priming system, an insulating grid (rod), a through-flow copper bar, an arc extinguishing chamber and the like (as shown in fig. 4).

When the fuse wire is normally used for passing through, current can flow through the through copper bar, and the endurance capacity of the fuse wire is greatly improved compared with that of a traditional fuse wire. When short circuit occurs, the initiating explosive device receives an ignition signal and is ignited, the high temperature and high pressure generated when the initiating explosive device is ignited push the insulating grid plate to move, and break the through-flow copper bar, so that the through-flow copper bar is divided into two parts and insulated and isolated. In the breaking process, the generated electric arc enters the arc extinguishing fuse containing the energy absorbing substance, absorbs energy and cools, and finally breaking is completed (as shown in fig. 5).

At present, most Pyro fuses are connected in series with a traditional Fuse wire for protection. When the short-circuit current is small, the automobile BMS detects the short-circuit current and sends a breaking signal to Pyro Fuse, and when the short-circuit current is large, the short-circuit current is automatically broken by a traditional Fuse wire.

Under the working condition of the electric automobile, the breaking capacity of Pyro Fuse is almost the same as that of the traditional Fuse, and the large short-circuit current can be broken, but the Pyro Fuse cannot act automatically and needs an external ignition signal to trigger. Due to the problems of the BMS system in terms of determination time, determination logic, etc., at least several hundred milliseconds are required from the occurrence of a short circuit to the detection of a short circuit and the signaling. If the short-circuit current is large, such as 10kA to 20kA, the components in the system cannot withstand the long time, and the damage is already caused before Pyro Fuse breaking.

Therefore, Pyro fuses with a trigger function have been developed to solve the trigger problem when Pyro fuses are individually cut.

The first is an electronic control product, the main manufacturer is Sensata, and on the basis of Pyro Fuse, a set of electronic measurement and control device is added, as shown in fig. 6.

The electric control device has the functions of detection and judgment, and a detection device is arranged in the electric control device and can sense the current in the loop. And calculating by using a built-in chip, judging whether the voltage exceeds a set threshold value or not, and forming a short circuit. If the short circuit is judged, an ignition signal is sent to the initiating explosive device, and the breaking is finished.

Compared with a BMS (battery management system), the electronic measurement and control device with the built-in electric control type Pyro Fuse is more flexible, lower in cost and capable of being designed according to different requirements in judgment logic. The sampling frequency is higher, the shortest time from short circuit to ignition signal sending can be in hundreds of microseconds, and the speed of the system is greatly improved compared with that of a BMS.

However, as electronic devices, there are more failure modes and greater failure probability during selection, assembly and use of components, and reliability remains uncertain, so that the electrically controlled Pyro Fuse is rare at present.

The second self-triggering type product is an arc-triggered Pyro Fuse, and an arc trigger is connected in series to the side of the Pyro Fuse (breaker) in order to quickly detect and generate an ignition signal at the time of a short circuit, as shown in fig. 7. The main principle of the arc trigger is similar to that of the traditional fuse, and the arc trigger can withstand rated current during normal operation and has stronger tolerance capability compared with the traditional fuse; when the short circuit current comes in, heat will quickly build up at the throat, which will blow and form a break when the temperature rises to the melting point of the melt, and an arc is formed at the break, as shown in fig. 8. According to the characteristic of the high-temperature arc, an arc voltage is formed at two ends of the arc-striking fuse and is used as a breaking signal to be sent to the breaker. The arc trigger is extremely fast compared to the BMS signal, and it detects the short circuit current in about tens of milliseconds.

In the Pyro fuses, initiating explosive devices are required to be used as acting energy sources. Most of the initiating explosive devices are igniters or products containing the igniters, and the igniters are dangerous as gunpowder products, require extremely severe use conditions and storage conditions, and have many limitations in design and use. In addition, the purchase, sale and transportation of the products of the fire drugs are strictly controlled by the state, and are very inconvenient. Meanwhile, when the trigger is used for detection and ignition, the connecting line between the trigger and gunpowder has the risk of poor contact or disconnection. .

Disclosure of Invention

The present invention is directed to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a circuit protection method and apparatus based on arc power, which uses the energy of the arc to replace the initiating explosive device as a power source, thereby improving the overall safety.

The technical scheme adopted by the invention is as follows: a circuit protection method based on arc work: when the circuit is in short circuit fault, the energy of the electric arc is used for acting to push the rod piece and disconnect the conductor connection, so that circuit breaking is realized.

In the above technical scheme, the electric arc is generated by an electric arc generator, and the electric conductor is a copper bar.

In the technical scheme, the arc generator and the copper bar are connected in series in the circuit; when the circuit is short-circuited, the arc generator is fused under the action of short-circuit current and starts to be burnt to generate energy, so that the rod piece in contact with the arc generator is pushed to move and cut off the copper bar, and the circuit is broken.

In the technical scheme, the rod piece cuts off the copper bar and then continues to move and enters the arc channel, and the electric arc is extruded into a gap between the arc channel and the rod piece and enters the arc extinguishing chamber; energy-absorbing materials are arranged in the arc extinguish chamber; the copper bar, the arc channel and the arc extinguish chamber are sequentially arranged along the motion direction of the rod piece.

In the technical scheme, short-circuit current generated after the circuit is disconnected is converted to an arc extinguishing fuse wire connected with the copper bar in parallel by the copper bar; the arc extinction fuse completes the arc extinction.

In the technical scheme, the rod piece cuts off the copper bar and then continues to move and enters the arc channel, and the electric arc is extruded into a gap between the arc channel and the rod piece; the copper bar and the arc channel are sequentially arranged along the motion direction of the rod piece.

In the technical scheme, a gap is formed between the head of the rod piece and the arc generator; after the short circuit occurs in the circuit, the energy generated by the arc generator increases the pressure in the gap between the head of the rod and the arc generator and acts on the head of the rod.

In the technical scheme, the arc generator detects the short-circuit current in real time; when the circuit is normally through-current, the arc generator withstands rated current; when the circuit is short-circuited, the current flowing through the arc generator exceeds a design threshold, the arc generator melts and begins to ignite.

In the above technical solution, the principle of the arc generator doing work is as follows:

according to an ideal gas state equation:

in the formula:pis the pressure in the gap between the head of the rod and the arc generator,Vis the volume of gas in the gap between the head of the rod and the arc generator,Tthe temperature in the gap between the head of the rod and the arc generator,nthe amount of material of the gas in the gap between the head of the rod and the arc generator,Ris a molar gas constant whennAndRthe volume of gas in the gap between the arc generator and the rod being constantVThe smaller, wherein the pressure in the gap between the head of the rod and the arc generatorpThe larger; pressure in the gap between the head of the rod and the arc generatorpThe rod piece is pushed to cut off the copper bar to realize the breaking of the circuit.

The invention also provides a circuit protection device based on arc acting, which comprises an arc generator and a conductor which are connected in series in a circuit; the device also comprises a rod piece; wherein the rod is in contact with the arc generator; the rod piece is positioned between the arc generator and the electric conductor; when the circuit is in short circuit fault, the arc generator emits energy to do work, and the rod piece is pushed to move to disconnect the conductor, so that circuit breaking is realized.

In the technical scheme, the device further comprises an arc extinguish chamber; the electric conductor is positioned between the arc extinguish chamber and the rod piece, electric arc generated by the electric arc generator enters the arc extinguish chamber, and energy absorbing substances are arranged in the arc extinguish chamber.

In the technical scheme, the arc extinguishing fuse wire is further included, and the arc extinguishing fuse wire is connected with the conductor in parallel; when the circuit is short-circuited, the short-circuit current is converted to the arc-extinguishing fuse wire through the conductor, and the arc-extinguishing fuse wire completes arc extinguishing.

In the technical scheme, a gap is formed between the head of the rod piece and the arc generator; after the short circuit occurs in the circuit, the energy generated by the arc generator increases the pressure in the gap and acts on the head of the rod.

In the technical scheme, the device further comprises a rod piece track; an arc channel is arranged between the arc extinguish chamber and the electric conductor; the rod piece is arranged in the rod piece track; under the action of the electric arc, the head of the rod moves in the rod track, and the tail of the rod moves in the arc channel.

In the technical scheme, the device further comprises a rod piece track; an arc channel is arranged between the arc extinguishing fuse and the conductor; the rod piece is arranged in the rod piece track; under the action of the electric arc, the head of the rod moves in the rod track, and the tail of the rod moves in the arc channel.

In the technical scheme, a gap exists between the outer surface of the tail part of the rod piece and the inner wall of the arc channel.

In the technical scheme, the rod pieces, the rod piece rails correspondingly arranged on the rod pieces, and the arc channels are all provided with a plurality of rod pieces.

The invention has the beneficial effects that: the invention adopts the electric arc generator to replace the initiating explosive device, thereby avoiding the inconvenience in purchasing, transporting, using and designing the initiating explosive device. The electric arc acting device adopted by the invention has a simpler and smaller structure, saves the connection process between gunpowder and the prior art, and has smaller volume and higher reliability. The working principle of the electric arc generator adopted by the invention is a pure physical process, and the ignition is more reliable compared with gunpowder. According to the invention, the extremely small gap is arranged between the arc generator and the head of the rod piece, so that the energy generated by the arc generator can effectively push the rod piece to cut off the copper bar. The invention provides an effective channel for the movement of the rod piece and the transfer of the electric arc through the rod piece track and the arc channel which are arranged on the rod piece and are coaxial. The invention provides two different arc extinguishing modes of the arc extinguishing chamber and the arc extinguishing fuse wire, thereby ensuring the use safety of the product and being further suitable for different working condition requirements. The invention provides a setting mode of the multiple rod pieces, further ensures that the multiple rod pieces can act simultaneously under the action of the arc generator, and ensures that the circuit is effectively cut off.

Drawings

FIG. 1 is a circuit diagram of a conventional fuse in the prior art;

FIG. 2 is an internal schematic diagram of a conventional fuse in the prior art;

FIG. 3 is a schematic circuit diagram of Pyro Fuse in the prior art;

FIG. 4 is a schematic diagram of Pyro Fuse in the prior art;

FIG. 5 is a schematic diagram of Pyro Fuse in the prior art;

FIG. 6 is a schematic circuit diagram of an electrically controlled Pyro Fuse in the prior art;

FIG. 7 is a schematic circuit diagram of an arc triggered Pyro Fuse in the prior art;

FIG. 8 is an internal schematic view of a prior art arc triggered Pyro Fuse;

FIG. 9 is a schematic circuit diagram of the present invention;

FIG. 10 is a schematic diagram of a simulation of the present invention;

FIG. 11 is a schematic structural diagram according to a first embodiment;

FIG. 12 is a simulation diagram according to a first embodiment;

FIG. 13 is a circuit diagram of a second embodiment;

FIG. 14 is a schematic structural diagram according to a second embodiment;

FIG. 15 is a simulation diagram of the second embodiment;

FIG. 16 is a schematic structural diagram of the third embodiment;

fig. 17 is a schematic structural diagram of a fourth embodiment.

Wherein, 1.1-initiating explosive device, 1.2-explosive chamber, 1.3-breaker, 1.4-insulating grid plate, 1.5-copper bar, 1.6-arc extinction; 1-circuit, 2-breaker, 3-rod, 4-arc generator, 5-gap between head of rod and arc generator, 6-rod track, 7-arc channel, 8-arc extinguish chamber, 9-arc extinguish fuse and 10-copper bar.

Detailed Description

The invention will be further described in detail with reference to the following drawings and specific examples, which are not intended to limit the invention, but are for clear understanding.

As shown in fig. 9, the present invention provides a circuit protection method based on arc work, which includes the following steps:

s1, the arc generator 4 and the copper bar 10 are both in normal through-current in the circuit 1;

s2, the circuit 1 is short-circuited, and the arc generator 4 is fused and starts to burn under the action of short-circuit current; the arc generator 4 generates a great deal of heat and a great deal of pressure to push the rod 3 in contact with the arc generator to move downwards;

s3, the copper bar 10 is cut off to break the circuit 1 during the downward movement of the rod 3 at high speed.

As shown in fig. 11, after the rod 3 cuts off the copper bar 10, the rod can continue to move and enter the arc channel 7, and the electric arc is extruded into a gap between the arc channel 7 and the rod 3 and enters the arc extinguish chamber 8; and an energy-absorbing material is arranged in the arc extinguishing chamber and is used for arc extinguishing.

Or, as shown in fig. 13, the short-circuit current generated after the circuit 1 is disconnected is converted to the arc-extinguishing fuse 9 connected in parallel with the copper bar 10 by the copper bar 10; the arc extinction fuse completes the arc extinction.

The basic working principle of the invention is as follows:

when the arc generator 4 and the copper bar 10 normally pass through the circuit 1 during normal operation, and the arrow in fig. 9 indicates the current direction.

When short circuit occurs, the arc generator 4 fuses and starts to burn after generating heat collecting effect under the action of short circuit current, and generates a large amount of heat and huge pressure, thereby pushing the rod piece 3 which is in contact with the arc generator to move. The rod 3 moves downwards at a high speed to cut off the copper bar 10 of the circuit 1.

The main functions of the arc generator 4 employed in the present invention are: 1. the short-circuit current is detected, and when the circuit works normally, the circuit can endure rated current; when a short circuit occurs and the current exceeds its design threshold, the internal fuse will blow and begin arcing. 2. After the arc is started, high temperature and high pressure are generated to push the rod 3 to move.

In the invention, the copper bar 10 and the rod piece 3 form the breaker 2, and the source of acting energy of the breaker is the arcing energy of the arc generator 4. The arc generator is composed of 2 metal sheets, and the 2 metal sheets are connected through a metal fuse. The metal sheet may be of two different metals. In the invention, the copper bar 10 can be replaced by the electric conductor made of other metal materials.

After the arc generator 4 is fused under the condition of short-circuit current, air breakdown can be formed at the fracture to generate an arc, and the arc is used as high-temperature plasma, and the temperature of the arc can reach ten thousand Kelvin. The arc heats up the surrounding air rapidly, which expands at a very high rate and generates a great pressure to move the rod 3.

The short-circuit current and the arc voltage are generated when the arc generator 4 is arcing. The heating power of the arc generator 4 can reach at least 200kW, which is basically similar to the power of an igniter tube with the 60mg grade, so that the arc generator 4 can be comparable to gunpowder in power. Meanwhile, the power of the arc generator 4 is changed according to the difference of the short-circuit current, and the larger the short-circuit current is, the larger the work power of the arc generator is.

In the initial state, there is a gap between the head of the rod 3 and the arc generator 4. According to an ideal gas state equation:

(wherein P is the pressure (Pa), V is the volume of gas (m), T is the temperature (K), n is the quantity of gaseous substance (mol), R is the molar gas constant (J/(mol. K))), and in the gap 5 between the arc generator 4 and the head of the rod 3, T is the arc temperature, assumed to be 50000K, in which the greater the pressure P generated by the air, the smaller the volume V of the space in the gap 5 between the arc generator 4 and the head of the rod 3, when n and R are constant. When the two are in close contact, i.e. V approaches infinity, the high temperature gas inside will generate a very large pressure.

According to experimental results and simulation calculations, as shown in fig. 10, the instantaneous maximum pressure in the gap 5 between the arc generator and the head of the rod 3 of 4 reaches 30MPa, the rod 3 can run at a speed of at least 50m/s, and the impulse generated by the gunpowder is larger and lasts longer than the duration of the impulse, so that the arc generator 4 can replace the gunpowder very well.

In the first embodiment, a direct-open arc type fuse (an arc acting device and an arc extinguish chamber 8) is adopted, and an arc is generated, and the breaker 2 is composed of the arc generating device 4, the copper bar 10 and the arc extinguish chamber 8, as shown in fig. 9. The direct-open arc type fuse uses an electric arc acting device and an arc extinguishing chamber 8 as a whole to form a complete direct current circuit protection device integrating detection, breaking and arc extinguishing. The specific internal component composition is shown in fig. 11.

The circuit protection device based on arc work in the first embodiment comprises an arc generator 4 and a copper bar 10 which are connected in series in a circuit 1; further comprising a rod member 3; wherein, the head of the rod 3 is positioned below the arc generator 4, and a gap exists between the head of the rod 3 and the arc generator 4; the tail part of the rod piece 3 is positioned above the copper bar 10; when the circuit 1 has a short-circuit fault, the energy of the arc generator 4 does work to push the rod piece 3 to move downwards to break the copper bar 10, so that the circuit 1 is disconnected.

Specifically, the arc extinguishing chamber 8 is provided below the copper bar 10. The electric arc generated by the electric arc generator 4 enters the arc extinguish chamber 8 through the rod piece 3 and the copper bar 10, and the arc extinguish chamber 8 is internally provided with an energy absorbing material for cooling the electric arc; the arc temperature is no longer maintained after the arc temperature has dropped below a threshold value in the arc chute 8, and is extinguished accordingly.

Specifically, after short circuit of the circuit 1, the heat and pressure generated by the arc generator 4 are conducted to the head of the rod 3 through the gap 5 between the head of the rod 3 and the arc generator 4; an arc channel 7 is arranged between the arc extinguish chamber 8 and the copper bar 10; in the downward movement process of the rod 3 under the action of the electric arc, the head of the rod 3 moves in the rod track 6, and the tail of the rod 3 moves in the arc channel 7; the rod piece track 6 and the arc channel 7 are both of cavity structures; the gap 5 between the head of the rod 3 and the arc generator 4, the rod 3, the rod track 6, the arc channel 7 and the arc chute 8 are arranged coaxially.

When in normal operation, the arc generator 4 and the copper bar 10 both normally flow through the circuit 1.

When short circuit occurs, the arc generator 4 generates heat collection effect under the action of short circuit current, fuses and starts to burn, and generates a large amount of heat and huge pressure, so that the rod 3 in contact with the arc generator is pushed to move. The rod 3 moves downwards at a high speed to cut off the copper bar 10 of the circuit 1.

After the rod 3 cuts off the copper bar 10 of the circuit 1, the rod 3 continues to move downwards at a high speed and enters the arc channel 7 below the copper bar 10, so that sufficient creepage distance is ensured between two sections of the broken copper bar 10 and the broken copper bar is not punctured; only a small gap is left between the arc channel 7 and the rod 3, and the electric arc is extruded into the gap and enters an arc extinguishing chamber 8 positioned below the arc channel 7. An energy absorbing material (metal or other types) is arranged in the arc extinguishing chamber 8, and the electric arc is cooled through the energy absorbing material. When the arc temperature falls below the threshold value, the arc temperature cannot be maintained any more, and then the arc is extinguished.

The method is used for carrying out a common maximum short-circuit working condition breaking experiment on the electric automobile. The specific working condition used is system voltage 700V, expected short-circuit current peak value 10kA, and loop inductance 20 uH. The test results are shown in fig. 12.

The platform current and the platform voltage are short-circuit current and voltage of the system, and the sample voltage is voltage at two ends of the direct-open arc type fuse (namely the sum of voltages at two ends of the arc generator 4 and the breaker 2).

At time 0, the short circuit begins to occur and the short circuit current begins to rise, at which time the value of the sample voltage is the product of its bulk resistance and the short circuit current.

At the time of 0.111ms, the short circuit current is detected by the arc generator 4, and the arc is started. It can be seen that the sample voltage suddenly rises to about 200V, which is the arc voltage generated when the arc generator 4 is arcing. Thereafter, the energy of the arcing starts to generate pressure and pushes the rod 3 to operate and break the copper bar 10 in the disconnector 2.

At the time of 0.305ms, the rod 3 is pushed by the arc generator 4 to break the copper bar 10 and start to enter the arc channel 7 downwards, and the arc generated by the breaker 2 also enters the arc channel 7 and the arc extinguishing chamber 8. The reason why the sample voltage rises rapidly at this time is that the arc is gradually elongated with the movement of the rod 3, and the arc is a resistance according to the law of resistance R = ρ × L/S (where ρ represents the resistivity of the resistance and is determined by its own properties, L represents the length of the resistance, and S represents the cross-sectional area of the resistance), and the arc of the breaker 2 is a resistance whose cross-sectional area is extremely small in the slit and whose length is increasing, and therefore its resistance is increasing and the voltage generated thereby is also increasing. When the arc voltage is greater than the system voltage, the short circuit current begins to drop under its overvoltage. The larger the arc voltage, the faster the current drops.

At 0.64ms, the short circuit current is reduced to a very small value, which does not cause damage to the system. The short circuit protection is completed.

In the first embodiment, short-circuit protection is completed within 1ms, and the insulation performance after the protection is completed is extremely excellent and can be more than 100M omega. The specific embodiment has the advantages of simple structure, low cost and high reliability, and the energy is generally 1-2 kJ when the electric automobile is applied.

The second embodiment is a hybrid arc type fuse (arc acting device is connected with an arc extinguishing fuse 9 in parallel). The mixed arc type fuse uses an arc acting device and an arc extinguishing fuse wire 9 as a whole to form a complete direct current circuit protection device integrating detection, breaking and arc extinguishing.

The basic composition of the hybrid arc type fuse is shown in fig. 13, and the specific internal component composition is shown in fig. 14.

The circuit protection device based on arc work in the second specific embodiment comprises an arc generator 4 and a copper bar 10 which are connected in series in a circuit 1; further comprising a rod member 3; a gap 5 is formed between the head of the rod piece 3 and the arc generator 4, the head of the rod piece 3 is positioned below the arc generator 4, and the tail of the rod piece 3 is positioned above the copper bar 10; when the circuit 1 has a short-circuit fault, the energy of the arc generator 4 does work to push the rod piece 3 to move downwards to break the copper bar 10, so that the circuit 1 is disconnected.

Specifically, the arc extinguishing fuse 9 is disposed below the copper bar 10. The rod 3 and the copper bar 10 together form the breaker 2. The copper bar 10 is connected in series in the circuit 1, and the arc extinguishing fuse 9 is connected in parallel at two ends of the copper bar 10. When the circuit 1 is short-circuited, the short-circuit current rapidly flows to the arc-extinguishing fuse wire 9 from the copper bar 10, and the arc-extinguishing fuse wire 9 starts arcing and is disconnected under the action of the short-circuit current to complete arc extinguishing.

Specifically, after short-circuiting of the circuit 1, the heat and pressure generated by the arc generator 4 are conducted to the head of the rod 3 through the gap 5 between the head of the rod 3 and the arc generator 4; an arc channel 7 is arranged between the arc extinguishing fuse 9 and the copper bar 10; during the downward movement of the rod 3 under the action of the electric arc, the head of the rod 3 moves in the rod track 6, the tail of the rod 3 moves in the arc channel 7, and the electric arc enters the arc channel 7 through the rod channel 6. Under the condition of the parallel copper bar 10 and the arc-extinguishing fuse 9, the electric arc which is broken by the rod 3 into the copper bar 10 and enters the arc channel 7 is very small, and the short-circuit current can rapidly flow to the arc-extinguishing fuse 9 after the arc voltage is generated by the arc generator 4, so that the electric arc of the arc channel 7 can be extinguished automatically. The rod piece track 6 and the arc channel 7 are both of cavity structures; the gap 5 between the head of the rod 3 and the arc generator 4, the rod 3, the rod track 6 and the arc path 7 are coaxially arranged.

When working normally, the arc generator 4 and the copper bar 10 both flow normally through the circuit 1, and there is almost no current flow over the quenching fuse 9, since the resistance of the quenching fuse 9 is much larger than that of the interrupter 2. The direction of the arrows in fig. 13 is the direction of current flow.

When short circuit occurs, the arc generator 4 generates heat collection effect fusing and starts to burn arc under the action of short circuit current, and generates a large amount of heat and huge pressure to push the rod piece 3 which is in contact with the arc generator to move. The rod 3 moves downwards at a high speed to cut off the copper bar 10 in the circuit 1.

After the rod 3 cuts off the copper bar 10 in the circuit 1, the rod continues to move downwards to enter the arc channel 7, so that enough creepage distance is ensured between two sections of the broken copper bar 10, and the broken copper bar is not punctured; short-circuit current rapidly commutates to the arc-extinguishing fuse 9 from the breaker 2, and the arc-extinguishing fuse 9 starts arcing and breaks under the action of the short-circuit current to complete arc extinguishing.

The hybrid arc type fuse is used for carrying out a common maximum short-circuit working condition breaking experiment on an electric automobile, wherein the working condition used here is system voltage 1000V, an expected short-circuit current peak value is 15kA, and loop inductance is 20 uH. The specific test results are shown in fig. 15.

The platform current and the platform voltage are the short-circuit current and the voltage of the system, and the sample voltage is the voltage at two ends of the direct-open arc type fuse (namely the sum of the voltages at two ends of the arc generator 4 and the breaker 2).

At time 0, the short-circuit current begins to rise, and the voltage of the sample is the product of the body resistance and the short-circuit current.

At the time of 0.558ms, the arc generator 4 detects the short-circuit current, starts to burn, and the energy of the burning starts to generate pressure and push the rod 3 to operate, and breaks the through-current copper bar 10 in the breaker 2.

At the time of 0.638ms, the rod 3 is pushed by the arc generator 4 to break the through-current copper bar 10, and as the breaker 2 is broken, the current gradually commutates to the arc-extinguishing fuse 9.

At the time of 0.78ms, the arc-extinguishing fuse 9 is ignited, the arc voltage is gradually increased, and the current is gradually reduced until zero crossing.

At the moment of 1.5ms, the short-circuit current is reduced to an extremely small value, and the system is not damaged. The short circuit protection is completed.

The insulation performance after protection is extremely excellent and can be larger than 1G omega. Compared with the specific embodiment, the specific embodiment two has the advantages that the structure and the process are relatively complex, the size is large, the breaking capacity is higher, and the breaking energy can reach 1-10 kJ or even more when the electric vehicle is applied.

As shown in fig. 16, in the third embodiment, on the basis of the first embodiment, a rod 3 and a corresponding arc path 7 and an arc extinguishing chamber are additionally arranged. The third specific embodiment comprises an arc generator 4 and a copper bar 10 which are connected in series in the circuit 1; also two rods 3; a gap 5 is formed between the head of each rod piece 3 and the arc generator 4, the head of each rod piece 3 is positioned below the arc generator 4, and the tail of each rod piece 3 is positioned above the copper bar 10; when the circuit 1 is in short circuit fault, the energy of the arc generator 4 does work to push the two rod pieces 3 to move downwards simultaneously to break the copper bar 10, so that the circuit 1 is broken. Arc channels 7 which are respectively matched with the tails of the two rod pieces 3 are arranged below the copper bar 10. An arc extinguish chamber is correspondingly arranged below each arc channel.

After the two rod pieces 3 cut off the copper bar 10 of the circuit 1, the two rod pieces 3 continue to move downwards at a high speed and enter the corresponding arc channel 7 below the copper bar 10, only a tiny gap is left between the arc channel 7 and the corresponding rod piece 3, and electric arcs are extruded into the gap and enter the corresponding arc extinguish chamber 8 below the arc channel 7. An energy absorbing material (metal or other types) is arranged in the arc extinguishing chamber 8, and the electric arc is cooled through the energy absorbing material. When the arc temperature falls below the threshold value, the arc temperature cannot be maintained any more, and then the arc is extinguished.

Compared with the single-rod structure of the first embodiment, the multi-rod structure of the third embodiment can be applied to the situation that the voltage of a circuit system is higher and the energy is larger.

As shown in fig. 17, a rod 3 and a corresponding arc path 7 are added to the second embodiment. The fourth specific embodiment comprises an arc generator 4 and a copper bar 10 which are connected in series in the circuit 1, wherein two ends of the copper bar 10 are connected with arc extinguishing fuses 10 in parallel; also two rods 3; gaps 5 are formed between the heads of the two rod pieces 3 and the arc generator 4, the heads of the two rod pieces 3 are positioned below the arc generator 4, and the tails of the two rod pieces 3 are positioned above the copper bar 10; when the circuit 1 has a short-circuit fault, the energy of the arc generator 4 does work to push the two rod pieces 3 to move downwards to break the copper bar 10, so that the circuit 1 is disconnected.

The arc extinguishing fuse 9 is arranged below the copper bar 10. The two rods 3 and the copper bar 10 form the breaker 2 together. When the circuit 1 is short-circuited, the short-circuit current rapidly flows to the arc-extinguishing fuse wire 9 from the copper bar 10, and the arc-extinguishing fuse wire 9 starts arcing and is disconnected under the action of the short-circuit current to complete arc extinguishing.

Compared with the single-rod structure of the second embodiment, the multi-rod structure of the fourth embodiment can be applied to the situation that the voltage of a circuit system is higher and the energy is larger.

Those not described in detail in this specification are within the skill of the art.

Claims

1. A circuit protection method based on arc work is characterized in that: when the circuit is in short circuit fault, the energy of the electric arc is used for acting to push the rod piece and disconnect the conductor connection, so that circuit breaking is realized.

2. The circuit protection method based on arc work as claimed in claim 1, wherein: the electric arc is generated by an electric arc generator, and the electric conductor is a copper bar.

3. The method of claim 2, wherein the method comprises:

the arc generator and the copper bar are connected in series in the circuit;

when the circuit is short-circuited, the arc generator is fused under the action of short-circuit current and starts to be burnt to generate energy, so that the rod piece in contact with the arc generator is pushed to move and cut off the copper bar, and the circuit is broken.

4. The circuit protection method based on arc work as claimed in claim 3, wherein: the rod piece cuts off the copper bar and then continues to move and enters the arc channel, and the electric arc is extruded into a gap between the arc channel and the rod piece and enters the arc extinguishing chamber; energy-absorbing materials are arranged in the arc extinguish chamber; the copper bar, the arc channel and the arc extinguish chamber are sequentially arranged along the motion direction of the rod piece.

5. The circuit protection method based on arc work as claimed in claim 3, wherein: short-circuit current generated after the circuit is broken is converted to an arc extinguishing fuse wire connected with the copper bar in parallel by the copper bar; the arc extinction fuse completes the arc extinction.

6. The circuit protection method based on arc work as claimed in claim 5, wherein: the rod piece cuts off the copper bar and then continues to move and enters the arc channel, and the electric arc is extruded into a gap between the arc channel and the rod piece; the copper bar and the arc channel are sequentially arranged along the motion direction of the rod piece.

7. The circuit protection method based on arc work as claimed in claim 2, wherein: a gap is formed between the head of the rod piece and the arc generator; after the short circuit occurs in the circuit, the energy generated by the arc generator increases the pressure in the gap between the head of the rod and the arc generator and acts on the head of the rod.

8. A circuit protection method based on arc work according to claim 4 or 5, characterized in that: the arc generator detects short-circuit current in real time; when the circuit is normally through-current, the arc generator withstands rated current; when the circuit is short-circuited, the current flowing through the arc generator exceeds a design threshold, the arc generator melts and begins to ignite.

9. The circuit protection method based on arc work as claimed in claim 7, wherein: the principle of the electric arc generator doing work is as follows:

according to an ideal gas state equation:

10. A circuit protection device based on electric arc does work, its characterized in that:

comprises an arc generator and a conductor connected in series in an electric circuit; the device also comprises a rod piece; wherein the rod is in contact with the arc generator; the rod piece is positioned between the arc generator and the electric conductor; when the circuit is in short circuit fault, the arc generator emits energy to do work, and the rod piece is pushed to move to disconnect the conductor, so that circuit breaking is realized.

11. The arc-based circuit protection device of claim 10, wherein: the device also comprises an arc extinguish chamber; the electric conductor is positioned between the arc extinguish chamber and the rod piece, electric arc generated by the electric arc generator enters the arc extinguish chamber, and energy absorbing substances are arranged in the arc extinguish chamber.

12. The arc-based circuit protection device of claim 10, wherein: the arc extinguishing fuse is connected with the conductor in parallel; when the circuit is short-circuited, the short-circuit current is converted to the arc-extinguishing fuse wire through the conductor, and the arc-extinguishing fuse wire completes arc extinguishing.

13. A circuit protection device based on arc-based power, as claimed in claim 11 or 12, wherein: a gap is formed between the head of the rod piece and the arc generator; after the short circuit occurs in the circuit, the energy generated by the arc generator increases the pressure in the gap and acts on the head of the rod.

14. The arc-based circuit protection device of claim 11, wherein: the device also comprises a rod piece track; an arc channel is arranged between the arc extinguish chamber and the electric conductor; the rod piece is arranged in the rod piece track; under the action of the electric arc, the head of the rod moves in the rod track, and the tail of the rod moves in the arc channel.

15. The arc-based circuit protection device of claim 12, wherein: the device also comprises a rod piece track; an arc channel is arranged between the arc extinguishing fuse and the conductor; the rod piece is arranged in the rod piece track; under the action of the electric arc, the head of the rod moves in the rod track, and the tail of the rod moves in the arc channel.

16. A circuit protection device based on arc-based power, as claimed in claim 14 or 15, wherein: a gap exists between the outer surface of the tail part of the rod piece and the inner wall of the arc channel.

17. A circuit protection device based on arc-based power, as claimed in claim 14 or 15, wherein: the rod pieces and the corresponding rod piece rails and arc channels are provided with a plurality of rod pieces.