High-temperature auxiliary high-frequency high-voltage power supply wire carbonization device

Abstract

The utility model discloses a high-temperature auxiliary high-frequency high-voltage power supply carbonization wire device. The device is composed of a constant-temperature sliding attaching mechanism, a master control circuit, a high-frequency high-voltage power supply, a detection switching circuit, a current detection circuit and a carbonization wire. And the constant-temperature heat conduction module moves to be tightly attached to the carbonized wire, and the wire is carbonized through heating. The high-frequency and high-voltage power source carbonizes the wire through high-frequency and high-voltage electricity, the main control circuit detects carbonization current through the mutual inductor, and when the carbonization current reaches a preset value, the heat conduction module is moved away, and power is cut off. The detection switching circuit switches the carbonized wire to a mains supply power supply state after carbonization is completed, then the performance of the carbonized wire is detected by detecting the carbonization current, and if the carbonization degree is insufficient, secondary carbonization is carried out. Therefore, good consistency, good performance and low rejection rate of carbonized wire products are guaranteed, and high automation degree and safe operation in the carbonization process are guaranteed.

Description

Technical Field

[0001] The utility model discloses a carbonization manufacturing device for a carbonized wire used in the research and development and testing of a fault arc. The device carbonizes the wire by using a high-frequency and high-voltage power supply with the aid of high temperature, and relates to the field of arc research and testing experimental equipment. Background Art

[0002] In recent years, arc fault protection technology and products have been rising continuously. When testing the performance of such products, a large number of carbonized wires are needed. The Chinese national standard "GB / T31143-2014 General Requirements for Arc Fault Protectors AFDD" provides the following method for making carbonized wires: First, two wires with a cross-sectional area of ​​1.5 square millimeters are bundled together, cut into a length of 200 mm, and separated into single strands of wire at 25 mm at both ends; the insulation layer between the wires is cut 50 mm, and the wires should be exposed without cutting the wires; secondly, the insulation cut is wrapped with two layers of PVC insulation tape, and then wrapped with two layers of glass fiber tape; the insulation of one end of each wire is stripped about 12 mm to connect the test circuit, which is called a carbonized wire blank. Connect the carbonized wire blank to a circuit with a short-circuit current of 30ma and an open-circuit voltage of more than 7kv, and energize for 10s or until the smoke stops; or connect it to a circuit with a short-circuit current of 300ma and a voltage of 2kv, and energize for 1min or until the smoke stops, and apply the two alternately; connect a 100w / 230v incandescent lamp in series in the carbonization circuit, and when the incandescent lamp begins to glow, the wire carbonization is considered to be completed. In this method, the production personnel operate 7KV high voltage electricity, which has poor safety and low efficiency. The force of knife cutting on the insulation layer and the elasticity and toughness of the insulation layer are difficult to master, so the depth of the incision is very inconsistent, some are deep and some are shallow. The time of carbonization is not easy to accurately grasp. The method of using incandescent lamps to detect current is very rough, and the current changes a lot. Incandescent lamps are thermal luminescent, and the current must heat the filament to an incandescent state before it can glow, which takes a certain amount of time, so the current measurement is very inaccurate. The above reasons lead to the large discreteness of the performance of the carbonized wire, poor product consistency, high scrap rate, poor safety and low efficiency. Therefore, it is necessary to invent an automated device to efficiently and safely complete the wire carbonization function and ensure good product consistency, good performance and low scrap rate. Summary of the invention

[0003] The principle of the "knife cutting" method given in the national standard is to artificially create a path with the worst insulation, guide the high-voltage power supply to perform high-voltage breakdown on this path with the worst insulation, and thus perform carbonization. The utility model abandons the mechanical implementation method of "knife cutting" and adopts the two methods of heating carbonization and high-frequency carbonization to jointly realize the automated carbonization wire device.

[0004] When the outer insulation of the carbonized wire blank is heated to more than 180 degrees Celsius, the insulation will be carbonized and the insulation performance will be significantly reduced. This is heating carbonization. The principle of high-frequency carbonization is as follows: The breakdown types of solid dielectrics can be divided into electrical breakdown, thermal breakdown and electrochemical breakdown. The factors affecting the breakdown of solid dielectrics mainly include the voltage action time, voltage frequency, temperature, electric field uniformity, etc. Among them, the voltage frequency has the most significant effect on thermal breakdown. Under the action of a strong electric field, heat is generated inside the dielectric due to loss. Theoretically, it is proved that the loss P and heat generation QF of the dielectric are linear functions of the frequency. The increase in voltage frequency will lead to an increase in dielectric loss P, making the dielectric heat generation much higher than the heat dissipation, causing thermal overload. At this time, the dielectric is easier to break down and then easier to further carbonize. Based on the above theory, the utility model adopts two methods to carbonize the wire. 1. Use a metal plate with good thermal conductivity, close to the carbonized wire to be carbonized, and heat the insulating sheath of the wire. This will significantly reduce the breakdown voltage of the insulating sheath at this point of the wire. Heating a certain point of the insulating sheath itself is the carbonization process of the insulating sheath at that point. 2. Use a high-frequency, high-voltage power supply to carbonize the wire. The high-frequency current of the power supply flows through the point on the insulating sheath where the insulation resistance is significantly reduced after being heated, thereby increasing the loss of the medium at the point on the insulating sheath that is heated and carbonized, causing the inside of the medium to heat up, thereby performing high-frequency carbonization. Because high-frequency pulse transformers have very significant advantages such as small size, light weight, and high efficiency. Therefore, the use of a high-frequency, high-voltage power supply can make the entire device small in size, light in weight, and highly efficient.

[0005] The utility model is composed of a constant temperature sliding and pressing mechanism, a total control circuit, a high frequency and high voltage power supply, a detection switching circuit, a current detection circuit and a carbonized wire. Figure 1 It is a constant temperature sliding and pressing mechanism. The stepper motor 1 drives the lead screw 3 to rotate through the coupling 2, driving the slide 4 to slide forward and backward. An insulating block 5 is installed on the side of the slide 4, and a heat conductive block 7 is installed on the side of the insulating block 5. A heating device 6 and a temperature sensor 10 are installed on the heat conductive block 7. The insulating bracket 9 supports the carbide wire 8 that needs to be carbonized. During operation, the slide 4 drives the heat conductive block 7 to move toward the carbide wire 8 and press against the carbide wire 8, and then heats the carbide wire blank under the control of the main control circuit. After the heating completion time is reached, the slider 4 drives the heat conductive block 7 to leave the carbide wire 8.

[0006] The overall control circuit senses the temperature through the temperature sensor 10, controls the heat-conducting block 7 to be in a constant temperature state by controlling the on and off of the power supply of the heating device 6, and controls the movement of the heat-conducting block 7 by controlling the stepper motor 1, thereby controlling the heating time of the carbonized wire and ensuring the consistency of the heating time for each carbonized wire.

[0007] Figure 2It is a high-frequency high-voltage power supply, which takes 220V AC mains 21 as input, becomes DC through a rectifier bridge and a filter capacitor, and then is inverted into high-frequency AC by an inverter circuit 22. The high-frequency AC is output to the primary coil of a high-frequency pulse transformer 24, and the secondary coil is boosted to an AC pulse high voltage of 4 kilovolts to 7 kilovolts. The AC pulse high voltage is output to two carbonized wire blanks 25 in the same insulating sheath that need to be carbonized; the lead-out connection line of the secondary coil of the high-frequency pulse transformer 24 passes through the center of the AC mutual inductor 26, and then is connected to an electrode of the carbonized wire blank 25, and the carbonization current signal will be collected by the AC mutual inductor 26;

[0008] The main control circuit detects the carbonization current, which increases continuously during the carbonization process. When the carbonization current reaches a preset threshold value, the main control circuit drives the stepper motor 1 to remove the heat conductive block 7, stop heating the heat conductive block 7, and disconnect the high-frequency high-voltage power supply at the same time, thereby completing the carbonization process of the wire.

[0009] like Figure 3 The utility model has a detection switching circuit to further detect the performance of the carbonized wire under the condition of mains power supply; the detection switching circuit is composed of two AC contactors 34, 35 as switching switches, so that the power supply of the carbonized wire 2 33 is switched between the high-frequency high-voltage power supply and the mains power; the high-frequency pulse transformer 2 31 provides a high-frequency high-voltage power supply, and the mains power isolation transformer 32 provides the mains power; after the carbonization is completed, the main control circuit outputs a control signal to switch the power supply of the carbonized wire 2 33 to the mains power supply, and the main control circuit detects whether the performance of the carbonized wire 2 33 meets the performance requirements when powered by the mains power through the AC mutual inductor 2 36. If it is found that the performance does not meet the requirements due to inadequate carbonization, the main control circuit continues to output a suitable control signal to perform a second round of carbonization.

[0010] like Figure 4 The utility model has a heating device 6. An AC contactor is connected in series in the heating circuit of the heating device 6 as a controlled switch to power on the heating device 6 for heating or power off for cooling; the AC contactor is controlled to be on and off by the heating control signal output by the total control circuit, and the PT100 platinum thermal resistor temperature sensor 41 and the other three resistors together form a bridge, all of which use resistors with a thousandth accuracy; the B terminal of the PT100 platinum thermal resistor is connected to a resistor, and the C terminal is connected to a programmable instrument amplifier 42 of model PGA204, and the amplification factor is set to 100; the programmable instrument amplifier 42 outputs a temperature signal to a universal comparator 43, which adopts a hysteresis comparison form, and its two threshold values ​​correspond to the temperature of stopping heating and starting heating; the comparator 43 outputs a signal to a control circuit 44 of the temperature control AC contactor composed of a driving transistor and a relay, and then outputs a temperature control signal to control the on and off of the temperature control AC contactor.

[0011] In the utility model, the carbonization control in the overall control circuit is implemented using a microcontroller, and the current signal of the current sensor is output to the microcontroller. The microcontroller samples through A / D, and then compares the relationship between this current value and the preset current value. When it is found that the measured current value reaches the preset current value, the microcontroller gives a control signal through GPIO, controls the high-frequency and high-voltage circuit to cut off the power, and controls the heat conductive block 7 to move to a position away from the carbonization wire 8, and cuts off the power, so that the carbonization is completed.

[0012] like Figure 5 In the utility model, the inverter circuit 22 in the high-frequency high-voltage power supply can use four IGBT tubes and use a standard full-bridge inverter circuit to implement it. The city power 51 is converted into direct current after bridge rectification, and is output to the high-frequency pulse transformer three 54 through the bridge inverter circuit 52 composed of four IGBTs. There is a high-frequency oscillator inside the inverter control circuit 53, and the oscillation frequency is tens of kilohertz to hundreds of kilohertz; the pulse signal of this frequency is simultaneously added to the two IGBT tubes located on the diagonal of the bridge inverter circuit, so that the two tubes located on the diagonal are turned on at the same time, the circuit is connected, and current is generated; after half a cycle of conduction, the two turned-on tubes are turned off, and the two tubes located on the other diagonal are turned on, the circuit is connected, and a current with a direction opposite to the current just now is generated; after one cycle, the rotation continues; the secondary coil loop of the high-frequency pulse transformer three 54 outputs the boosted voltage to the carbonized wire three 55, and the AC transformer three 56 is responsible for sampling the current in the secondary loop.

[0013] The utility model abandons the method of "knife cutting" which adopts mechanical method to make carbonized wire, and discloses a device that adopts heating carbonization and high-frequency carbonization to realize carbonization of wire together. The operator does not need to contact high voltage electricity, the degree of automation is high, and the operation is safe. The heating temperature, heating time, frequency and voltage of high-voltage power supply, and power-on time can all be accurately controlled. The current flowing through the carbonized wire is used as the judgment criterion of whether carbonization is completed. This current can be measured very accurately, and the measurement time can be very short, and can be measured in milliseconds. The heating temperature, heating time, frequency and voltage of high-voltage power supply, power-on time and heating effect constitute a closed-loop control, that is, if any of the above parameters except carbonization current changes due to errors, it will cause the carbonization time to become faster or slower. Regardless of whether this time becomes faster or slower, as long as the carbonization current reaches a preset value, the total control circuit will control the completion of carbonization, so the carbonization current when the carbonization is finally stopped is a preset fixed value and is unchanged, that is, the parameter error does not affect the carbonization result with the fixed carbonization current as the judgment criterion. The utility model ensures that the carbonized wire product has good consistency, good performance, and low scrap rate, and ensures that the carbonization process has a high degree of automation and safe operation. The utility model will play a certain role in promoting the development of fault arc products. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the axonometric view of the constant temperature sliding and pressing mechanism.

[0015] Figure 2 It is a block diagram of high frequency and high voltage power supply.

[0016] Figure 3 This is the detection switching circuit diagram.

[0017] Figure 4 This is a circuit diagram of an embodiment of temperature control.

[0018] Figure 5 The invention is a circuit diagram of an embodiment of a high-frequency and high-voltage power supply. DETAILED DESCRIPTION

[0019] One embodiment of the constant temperature sliding clamping mechanism is as follows: purchase a commercial slide table composed of a stepper motor, a coupling, a slide rail, a lead screw, a bracket, etc., use bakelite to machine the base, the heat-insulating block 5 and the insulating bracket 9, and use copper or aluminum to machine the heat-conducting block 7. Purchase a commercial PTC heater powered by 220VAC as a heating device 6, and purchase a commercial temperature sensor as a temperature sensor 10. The specific model parameters of the temperature sensor are as follows: PT100 platinum thermal resistor temperature sensor, the resistance grade is F0.30, the temperature range is -70 degrees Celsius to 500 degrees Celsius, and it is a positive temperature coefficient, that is, the higher the temperature, the greater the resistance value. Assemble these parts according to Figure 1 The constant temperature sliding and pressing mechanism can be completed by assembling them together.

[0020] The overall control circuit is completed by a microcontroller according to the control logic relationship described in the utility model, and a universal microcontroller is purchased.

[0021] The inverter circuit 22 in the high-frequency high-voltage power supply can be implemented using four general-purpose IGBT tubes and a standard full-bridge inverter circuit.

[0022] The detection switching circuit is composed of two AC contactors, and the current detection circuit is composed of a magnetic ring, a general operational amplifier and a logic circuit.

[0023] The method for making the carbonized wire blank is as follows: two wires with a cross-sectional area of ​​1.5 square millimeters are bundled together, cut into a length of 200 mm, and separated into single-strand wires at 25 mm at both ends.

Claims

1. A high temperature auxiliary high frequency high voltage power supply carbonized wire device, characterized in that: The invention comprises a constant temperature sliding and pressing mechanism, a general control circuit, a high frequency and high voltage power supply, a detection switching circuit, a current detection circuit, and a carbonized wire; the constant temperature sliding and pressing mechanism is driven by a stepping motor (1) through a coupling (2) to drive a lead screw (3) to rotate, thereby driving a slide table (4) to slide forward and backward; a heat insulating block (5) is installed on the side of the slide table (4), a heat conducting block (7) is installed on the side of the heat insulating block (5), and a heating device (6) and a temperature sensor (10) are installed on the heat conducting block (7); an insulating bracket (9) supports When working, the slide table (4) drives the heat conducting block (7) to move toward the carbonized wire (8) and press against the carbonized wire (8) to heat it. After carbonization is completed, the slide table (4) drives the heat conducting block (7) to leave the carbonized wire (8). The overall control circuit senses the temperature through the temperature sensor (10), controls the power supply of the heating device (6) to control the heat conducting block (7) to be in a constant temperature state, and controls the movement of the heat conducting block (7) by controlling the stepping motor (1), thereby controlling the heating of the carbonized wire (8). The heating time is ensured to ensure the consistency of the heating time for each carbonized wire; the high-frequency high-voltage power supply is inputted by 220V AC mains (21), which is converted into DC power through a rectifier bridge and a filter capacitor, and then inverted into high-frequency AC power by an inverter circuit (22), and the high-frequency AC power is output to the primary coil of a high-frequency pulse transformer (24), and the secondary coil is stepped up to an AC pulse high voltage of 4 kilovolts to 7 kilovolts, and the AC pulse high voltage is output to two carbonized wire blanks (25) in the same insulating sheath to be carbonized; the high-frequency pulse transformer ( The lead-out wire of the secondary coil of the carbonized wire (24) passes through the center of the AC mutual inductor (26) and is then connected to an electrode of the carbonized wire blank (25). The carbonization current signal is then collected by the AC mutual inductor (26). The overall control circuit detects the carbonization current. During the carbonization process, the carbonization current continuously increases. When the carbonization current reaches a preset threshold value, the overall control circuit drives the stepper motor (1) to remove the heat conductive block (7), stop heating the heat conductive block (7), and simultaneously disconnect the high-frequency high-voltage power supply, thereby completing the carbonization process of the wire.

2. The high temperature auxiliary high frequency high voltage power carbonized wire device according to claim 1, characterized in that: The invention has a detection switching circuit for further detecting the performance of the carbonized wire under the condition of mains power supply; the detection switching circuit is composed of two AC contactors (34) and (35) as switching switches, so that the power supply of the second carbonized wire (33) is switched between the high-frequency high-voltage power supply and the mains power supply; the second high-frequency pulse transformer (31) provides the high-frequency high-voltage power supply, and the mains power isolation transformer (32) provides the mains power supply; after the carbonization is completed, the main control circuit outputs a control signal to switch the power supply of the second carbonized wire (33) to the mains power supply, and the main control circuit detects whether the performance of the second carbonized wire (33) meets the performance requirements when the mains power supply is provided through the second AC mutual inductor (36). If it is found that the performance does not meet the requirements due to inadequate carbonization, the main control circuit continues to output a suitable control signal to carry out a second round of carbonization.

3. The high temperature auxiliary high frequency high voltage power carbonized wire device according to claim 1, characterized in that: An AC contactor is connected in series in the heating circuit of the heating device (6) as a controlled switch to power on the heating device (6) for heating or power off for cooling. The AC contactor is controlled to be turned on and off by a heating control signal output by a total control circuit. A PT100 platinum thermal resistor temperature sensor (41) and other three resistors together form a bridge, all of which use resistors with a thousandth accuracy. The B terminal of the PT100 platinum thermal resistor is connected to a resistor, and the C terminal is connected to a programmable instrument amplifier (42) of model PGA204, with an amplification factor set to 100. The programmable instrument amplifier (42) outputs a temperature signal to a universal comparator (43), which uses a hysteresis comparison form, and its two threshold values ​​correspond to the temperatures for stopping heating and starting heating. The comparator (43) outputs a signal to a control circuit (44) of the temperature control AC contactor composed of a driving transistor and a relay, and then outputs a temperature control signal to control the on and off of the temperature control AC contactor.

4. The high temperature auxiliary high frequency high voltage power carbonized wire device according to claim 1, characterized in that: The carbonization control in the overall control circuit is implemented by a microcontroller, and the current signal of the current sensor is output to the microcontroller. The microcontroller samples through A / D, and then compares the relationship between the current value and the preset current value. When it is found that the measured current value reaches the preset current value, the microcontroller gives a control signal through GPIO to control the high-frequency high-voltage circuit to cut off the power, and controls the heat conductive block 7 to move to a position away from the carbonization wire (8), and cuts off the power, so that the carbonization is completed.

5. The high temperature auxiliary high frequency high voltage power carbonized wire device according to claim 1, characterized in that: The inverter circuit (22) in the high-frequency high-voltage power supply can use four IGBT tubes and use a standard full-bridge inverter circuit to implement it. The city power (51) is converted into direct current after bridge rectification, and is output to the high-frequency pulse transformer three (54) through the bridge inverter circuit (52) composed of four IGBTs. The inverter control circuit (53) has a high-frequency oscillator inside, and the oscillation frequency is tens of kilohertz to hundreds of kilohertz; the pulse signal of this frequency is simultaneously added to the two IGBT tubes located on the diagonal of the bridge inverter circuit, so that the two tubes located on the diagonal are turned on at the same time, the circuit is connected, and current is generated; after half a cycle of conduction, the two turned-on tubes are turned off, and the two tubes located on the other diagonal are turned on, the circuit is connected, and a current with a direction opposite to the previous current is generated; after one cycle, the rotation continues; the secondary coil loop of the high-frequency pulse transformer three (54) outputs the boosted voltage to the carbon wire three (55), and the AC transformer three (56) is responsible for sampling the current in the secondary loop.

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