Impact-dc dual working condition pipeline degaussing device

Abstract

The utility model discloses a kind of impact-direct current double working condition pipeline degaussing device, including three-phase rectifier bridge, controller, degaussing coil, filter circuit and high-voltage impact discharge circuit, the positive pole of three-phase rectifier bridge DC output end is connected with the collector of IGBT module Q1;The input end of the filter circuit is connected with the emitter of IGBT module Q1 and the negative pole output of three-phase rectifier bridge 1 by first switching switch K1, the input end of the high-voltage impact discharge circuit is connected with the emitter of IGBT module Q1 and the negative pole output of three-phase rectifier by second switching switch K2, the utility model contains constant-current output circuit and high-voltage impact discharge circuit, can output constant direct current or high-voltage pulse current to degaussing coil as required, a device can realize two working modes of constant-current degaussing and impact degaussing, constant-current output and high-voltage impact discharge circuit share a set of rectifier module and an IGBT module, structure is simpler.

Description

Technical Field

[0001] This utility model belongs to the technical field of pipeline demagnetization equipment, specifically a pipeline demagnetization device with both impact and DC operating conditions. Background Technology

[0002] Steel oil pipelines develop residual magnetism during manufacturing, transportation, and installation. This residual magnetism can negatively impact welding quality, causing issues such as arc blow, porosity, and even weld failure. Therefore, it is essential to eliminate residual magnetism from the pipeline before welding.

[0003] Pipe demagnetization mainly includes two methods: DC demagnetization and pulse demagnetization. Constant current demagnetization refers to applying a stable and strong DC current to the coil using a demagnetizer, thereby creating a stable magnetic field inside the pipe. This causes the magnetization of the pipe wall material to reach or approach saturation, meaning all its magnetic domains are roughly oriented. After maintaining this state for a period of time, the current is reduced to zero by the demagnetizer. As the external magnetic field weakens, the magnetic domains inside the material gradually return from an ordered arrangement to a random, disordered state. Residual magnetism also approaches zero. Pulse demagnetization, also known as impact demagnetization, involves a demagnetizer releasing a large, instantaneous current pulse of opposite polarity into a coil. This generates a powerful, instantaneous reverse magnetic field, forcing the magnetic domains of the pipe material to rapidly flip back and forth. As the magnetic field amplitude decays to zero, the magnetic domains eventually settle in random directions, thus achieving macroscopic demagnetization.

[0004] Existing demagnetizing devices are usually designed for single-condition operation, only having DC demagnetizing function and unable to output pulse impulse current. Demagnetizing devices with impulse-DC dual-condition operation usually install two power supply units in one device. Both power supply units use their own rectifier modules (high voltage and low voltage rectifier modules) and power modules, which makes the structure more complex and the cost higher. Utility Model Content

[0005] This invention proposes an impact-DC dual-condition pipeline demagnetization device, which aims to solve the problems of the single function of existing pipeline demagnetization devices and the complex structure of existing dual-condition demagnetization devices.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A dual-condition (impulse-DC) pipeline demagnetizing device includes a three-phase rectifier bridge, a controller, a demagnetizing coil, a filter circuit, and a high-voltage impulse discharge circuit. The input terminal of the three-phase rectifier bridge is connected to an AC 380V power supply, and the positive terminal of the DC output terminal of the three-phase rectifier bridge is connected to the collector of an IGBT module Q1. The input terminal of the filter circuit is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge 1 through a first switching switch K1. The input terminal of the high-voltage impulse discharge circuit is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge 1 through a second switching switch K2. The output terminals of both the filter circuit and the high-voltage impulse discharge circuit are connected to the demagnetizing coil 3. The high-voltage impulse discharge circuit includes a step-up transformer and a silicon controlled rectifier (SCR1). The primary coil of the step-up transformer is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge through a second switching switch K2. The secondary coil of the step-up transformer is connected in parallel with an energy storage capacitor C3. The positive terminal of the energy storage capacitor C3 is connected to the anode of the silicon controlled rectifier (SCR1). The cathode of the silicon controlled rectifier (SCR1) and the negative terminal of the energy storage capacitor C3 are respectively connected to the two ends of the demagnetizing coil. The output terminal of the controller is connected to the gate of the IGBT module Q1 and the gate of the thyristor SCR1, respectively, and is used to control the duty cycle of the IGBT module output and the on / off state of the thyristor SCR1.

[0007] Preferably, the filter circuit includes a filter capacitor C2 and a reactance L1, wherein the filter capacitor C2 is connected in parallel with the demagnetizing coil 3, and the reactance L1 is connected in series between the filter capacitor C2 and the demagnetizing coil 3.

[0008] Preferably, a discharge resistor R1 is connected in parallel between the two terminals of the energy storage capacitor C3, and a discharge switch K3 is connected between the discharge resistor R1 and the positive terminal of the energy storage capacitor C3.

[0009] Preferably, a voltage acquisition device is connected in parallel between the two poles of the energy storage capacitor C3, and the signal output terminal of the voltage acquisition device is connected to the analog input of the controller.

[0010] Preferably, a smoothing capacitor C1 is connected in parallel to the output terminal of the three-phase rectifier bridge.

[0011] Preferably, diodes D1 and D2 are connected in series between the output terminal of the filter circuit and the demagnetizing coil. Diodes D1 and D2 are used to block the output current of the high-voltage impulse discharge circuit from entering the filter circuit.

[0012] Preferably, the controller 2 includes a PWM controller and a SCR controller. The PWM controller is connected to the gate of the IGBT module Q1 through a gate drive circuit and is used to control the frequency and duty cycle of the output of the IGBT module Q1. The SCR controller is connected to the gate of the SCR1 through an isolation circuit and is used to control the on / off state of the SCR1.

[0013] Beneficial effects Compared with the prior art, the present invention can achieve at least the following technical effects: 1. This utility model includes a constant current output circuit and a high-voltage impulse discharge circuit, which can output a constant DC current or a high-voltage pulse current to the demagnetizing coil as needed. One device can realize two working modes: constant current demagnetization and impulse demagnetization.

[0014] 2. The constant current output and high-voltage impulse discharge circuit of this utility model share a set of rectifier modules and an IGBT module, which makes the structure simpler, saves equipment costs, and makes the device lighter overall. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the circuit structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the state during DC demagnetization of this utility model.

[0017] Figure 3 This is a schematic diagram of the state during impact demagnetization of this utility model.

[0018] In the diagram: 1. Three-phase rectifier bridge; 2. Controller; 3. Demagnetizing coil; 4. Step-up transformer; 5. Filter circuit; 6. High-voltage impulse discharge circuit; 7. Voltage acquisition device. Detailed Implementation

[0019] The present invention will be further explained below with reference to specific implementation examples.

[0020] Please see Figure 1-3This utility model proposes a dual-condition (impact-DC) pipeline demagnetizing device, comprising a three-phase rectifier bridge 1, a controller 2, a demagnetizing coil 3, a filter circuit 5, and a high-voltage impulse discharge circuit 6. The input terminal of the three-phase rectifier bridge 1 is connected to an AC 380V power supply, and the positive terminal of the DC output terminal of the three-phase rectifier bridge 1 is connected to the collector of the IGBT module Q1. The input terminal of the filter circuit is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge 1 through a first switching switch K1. The input terminal of the high-voltage impulse discharge circuit 6 is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge 1 through a second switching switch K2. The output terminals of the filter circuit 5 and the high-voltage impulse discharge circuit 6 are both connected to the demagnetizing coil 3. The high-voltage impulse discharge circuit 5 includes a step-up transformer 4 and a silicon controlled rectifier (SCR) 1. The primary coil of the step-up transformer 4 is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge 1 through a second switching switch K2. The secondary coil of the step-up transformer 4 is connected in parallel with an energy storage capacitor C3. The positive terminal of the energy storage capacitor C3 is connected to the anode of the silicon controlled rectifier (SCR) 1. The cathode of the silicon controlled rectifier (SCR) 1 and the negative terminal of the energy storage capacitor C3 are respectively connected to the two ends of the demagnetizing coil 3. The output terminal of the controller 2 is connected to the gate of the IGBT module Q1 and the gate of the thyristor SCR1, respectively, and is used to control the duty cycle of the IGBT module output and the on / off state of the thyristor SCR1.

[0021] like Figure 2 As shown, when the device is working in DC demagnetization mode, the first switching switch K1 is closed and the second switching switch K2 is open. The three-phase rectifier bridge 1 converts the AC380V power frequency power supply into DC. The controller 2 controls the frequency, pulse width and duty cycle of the IGBT module Q1 by inputting a square wave signal to the gate of the IGBT module Q1. The DC square wave pulse output by the IGBT module Q1 is converted into a constant DC output by the filter circuit 5, thereby allowing a constant DC current to pass through the demagnetization coil 3, thus forming a stable magnetic field inside the pipe, so that the magnetization intensity of the pipe wall material reaches or approaches saturation. After a period of time, the effective value of the output pulse current of the IGBT module Q1 can be adjusted by controlling the duty cycle of the gate input signal of the IGBT module Q1, which in turn can adjust the current in the demagnetizing coil 3, so that the current in the demagnetizing coil 3 gradually decreases, and the magnetic domains inside the pipe material gradually return from an ordered arrangement to a random disordered state.

[0022] like Figure 3As shown, when the device operates in the impact demagnetization mode, the second switching switch K2 is closed and the first switching switch K1 is open. The IGBT module Q1 outputs pulsed DC current to the primary coil of the step-up transformer 4 to excite the primary coil, and outputs pulsed DC current of 1000~1200V to the secondary coil to charge the energy storage capacitor C3. When the energy storage capacitor C3 is fully charged, the controller 2 controls the IGBT module Q1 to turn off and simultaneously controls the thyristor SCR1 to turn on. The energy storage capacitor C3 releases pulsed impact current to the demagnetization coil 3, which generates a strong instantaneous reverse magnetic field in the pipe material through the demagnetization coil 3, forcing the magnetic domains of the pipe material to flip back and forth at high speed.

[0023] In this embodiment, the filter circuit 5 is further configured to include a filter capacitor C2 and a reactance L1, wherein the filter capacitor C2 is connected in parallel with the demagnetizing coil 3, and the reactance L1 is connected in series between the filter capacitor C2 and the demagnetizing coil 3.

[0024] In this embodiment, the filter circuit 5 is an LC filter circuit composed of capacitor C2 and reactance L1. The cooperation of capacitor C2 and reactance L1 converts the pulsed DC power output by IGBT module Q1 into smooth DC power.

[0025] In this embodiment, a discharge resistor R1 is connected in parallel between the two poles of the energy storage capacitor C3, and a discharge switch K3 is connected between the discharge resistor R1 and the positive pole of the energy storage capacitor C3.

[0026] After the impact demagnetization is completed, there may still be residual charge in the energy storage capacitor C3. By turning on the discharge switch K3, the residual charge in the energy storage capacitor C3 can be consumed through the discharge resistor R1, thereby improving the safety of the device.

[0027] In this embodiment, a voltage acquisition device 7 is connected in parallel between the two poles of the energy storage capacitor C3, and the signal output terminal of the voltage acquisition device 7 is connected to the analog input of the controller 2.

[0028] By setting up a voltage acquisition device 7, the voltage across the energy storage capacitor C3 can be obtained. The voltage acquisition device 7 transmits the voltage signal to the controller 2, which compares it with the set value through the comparison circuit in the controller 2 to determine whether to continue or stop charging the energy storage capacitor C3.

[0029] In this embodiment, a smoothing capacitor C1 is connected in parallel to the output terminal of the three-phase rectifier bridge 1.

[0030] By setting the smoothing capacitor C1, the high-frequency pulse component contained in the output of the three-phase rectifier bridge 1 can be eliminated.

[0031] In this embodiment, diodes D1 and D2 are connected in series between the output terminal of the filter circuit 5 and the demagnetizing coil 3. The diodes D1 and D2 are used to block the output current of the high-voltage impulse discharge circuit 6 from entering the filter circuit 5.

[0032] The connection directions of D1 and D2 are as follows: Figure 1 As shown, diodes D1 and D2 are used to block the output current of the high-voltage impulse discharge circuit 6 from entering the filter circuit 5, so as to prevent the high-voltage pulse from breaking down the filter capacitor C2 of the filter circuit 5.

[0033] In this embodiment, the controller 2 is further configured to include a PWM controller and a SCR controller. The PWM controller is connected to the gate of the IGBT module Q1 through a gate drive circuit and is used to control the frequency and duty cycle of the output of the IGBT module Q1. The SCR controller is connected to the gate of the SCR1 through an isolation circuit and is used to control the on / off state of the SCR1.

[0034] Among them, the PWM controller is a general-purpose PWM controller, such as the UC384 series, which is used to generate PWM signals and drive the IGBT module Q1 through the gate drive circuit; the thyristor controller is an ASIC control chip, which controls the on and off of the thyristor SCR1 through peripheral circuits.

[0035] In summary, a constant DC current or high-voltage pulse current can be output to the demagnetizing coil 3 as needed. One device can realize two working modes: constant current demagnetization and impulse demagnetization. Moreover, the constant current output section and the high-voltage impulse output section share a three-phase rectifier bridge 1 and an IGBT module Q1, which makes the structure simpler, saves equipment costs, and makes the device lighter overall.

[0036] In the description of this utility model, the term "multiple" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0037] In the description of this utility model, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this utility model, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A dual-condition (impact-DC) pipeline demagnetization device, characterized in that, The system includes a three-phase rectifier bridge (1), a controller (2), a demagnetizing coil (3), a filter circuit (5), and a high-voltage impulse discharge circuit (6). The input terminal of the three-phase rectifier bridge (1) is connected to an AC380V power supply, and the positive terminal of the DC output terminal of the three-phase rectifier bridge (1) is connected to the collector of the IGBT module Q1. The input terminal of the filter circuit is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge (1) through a first switching switch K1. The input terminal of the high-voltage impulse discharge circuit (6) is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge (1) through a second switching switch K2. The output terminals of the filter circuit (5) and the high-voltage impulse discharge circuit (6) are both connected to the demagnetizing coil (3). The high-voltage impulse discharge circuit (6) includes a step-up transformer (4) and a thyristor SCR1. The primary coil of the step-up transformer (4) is connected to the emitter of the IGBT module Q1 and the negative output of the three-phase rectifier bridge (1) through the second switching switch K2. The secondary coil of the step-up transformer (4) is connected in parallel with an energy storage capacitor C3. The positive terminal of the energy storage capacitor C3 is connected to the anode of the thyristor SCR1. The cathode of the thyristor SCR1 and the negative terminal of the energy storage capacitor C3 are respectively connected to the two ends of the demagnetizing coil (3). The output terminal of the controller (2) is connected to the gate of the IGBT module Q1 and the gate of the thyristor SCR1, respectively, and is used to control the duty cycle of the IGBT module output and the on / off state of the thyristor SCR1.

2. The impact-DC dual-condition pipeline demagnetization device according to claim 1, characterized in that, The filter circuit includes a filter capacitor C2 and a reactance L1. The filter capacitor C2 is connected in parallel with the demagnetizing coil (3), and the reactance L1 is connected in series between the filter capacitor C2 and the demagnetizing coil (3).

3. The impact-DC dual-condition pipeline demagnetization device according to claim 1, characterized in that, A discharge resistor R1 is connected in parallel between the two terminals of the energy storage capacitor C3, and a discharge switch K3 is connected between the discharge resistor R1 and the positive terminal of the energy storage capacitor C3.

4. The impact-DC dual-condition pipeline demagnetization device according to claim 1, characterized in that, A voltage acquisition device (7) is connected in parallel between the two poles of the energy storage capacitor C3, and the signal output terminal of the voltage acquisition device (7) is connected to the analog input of the controller (2).

5. The impact-DC dual-condition pipeline demagnetization device according to claim 1, characterized in that, A smoothing capacitor C1 is connected in parallel to the output terminal of the three-phase rectifier bridge (1).

6. The impact-DC dual-condition pipeline demagnetization device according to claim 1, characterized in that, A diode D1 and a diode D2 are connected in series between the output terminal of the filter circuit (5) and the demagnetizing coil (3). The diodes D1 and D2 are used to block the output current of the high-voltage impulse discharge circuit (6) from entering the filter circuit (5).

7. The impact-DC dual-condition pipeline demagnetization device according to claim 1, characterized in that, The controller (2) includes a PWM controller and a thyristor controller. The PWM controller is connected to the gate of the IGBT module Q1 through a gate drive circuit and is used to control the frequency and duty cycle of the output of the IGBT module Q1. The thyristor controller is connected to the gate of the thyristor SCR1 through an isolation circuit and is used to control the on and off of the thyristor SCR1.

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