One-way discharge circuit of inverter energy storage welding machine

Abstract

According to the unidirectional discharge circuit of the inverter energy storage welding machine, a welding transformer is demagnetized automatically after current one-time welding is completed, the problem of magnetization of the welding transformer during unidirectional discharge is solved, unidirectional discharge of the inverter energy storage welding machine is achieved, the overall process integrity is improved, and meanwhile the production cost is reduced. And the service life of all working data is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of inverter energy storage welding machines, and particularly relates to a unidirectional discharge circuit of an inverter energy storage welding machine. Background Art

[0002] The main circuit of an inverter energy storage welding machine usually adopts a full-bridge inverter structure. By controlling 4 IGBTs to conduct alternately according to a certain rule, the forward and reverse discharges of the welding transformer are realized. One welding is a forward discharge, as Figure 1 shown, and one welding is a reverse discharge, as Figure 2 shown. The 4 IGBTs conduct alternately to ensure the normal operation of the transformer.

[0003] This method is applicable to workpieces with the same material and thickness on both sides, while for workpieces with different materials and thicknesses on both sides, the welding effect will be inconsistent. The main reason is that the direction of the current is different, and the direction of the magnetic field generated around is also different, so the amount of heat generated on the workpiece is slightly different.

[0004] With the wider and wider application range of inverter energy storage welding machines, for workpieces with inconsistent sides (such as different thicknesses and materials), unidirectional discharge must be adopted, otherwise the welding effect will be inconsistent. Adopting unidirectional discharge will cause magnetization of the transformer core, resulting in a decrease in the welding current and magnetic saturation of the transformer, etc., making it impossible to complete high-strength welding based on the existing technology for the overall process.

[0005] For example: the welding of nuts, as Figure 3 shown. Figure 3 In (a) is a schematic diagram of a nut, Figure 3 In (b) is a schematic diagram of the nut placed on a steel plate. Nut welding is generally to weld the nut on the steel plate. The nut has a small volume and a large thickness, while the steel plate has a large volume and a small thickness, belonging to an asymmetric workpiece. Nut welding has high requirements for the current. If the current is too small, it is easy to have a false weld, and if the current is too large, it is easy to cause the workpiece with the thread deformed to be scrapped. For nut welding and the welding of some asymmetric workpieces, only unidirectional discharge can achieve a relatively ideal welding effect. Summary of the Utility Model

[0006] The problem to be solved by the utility model is the magnetization of the transformer core caused by unidirectional discharge.

[0007] To solve the above problems, the technical solution of the utility model is to provide a unidirectional discharge circuit of an inverter energy storage welding machine, including:

[0008] The charging circuit is electrically connected to the energy storage capacitor through a plurality of diodes in the rectifying circuit to form a charging branch;

[0009] The positive electrode of the energy storage capacitor is connected to one end of switch V1, the other end of switch V1 is connected to one end of the welding transformer, the other end of the welding transformer is connected to one end of switch V4, and the other end of switch V4 is connected to the negative electrode of the energy storage capacitor to form a discharge branch circuit;

[0010] The positive electrode of the energy storage capacitor is connected to one end of the bleeder resistor, the other end of the bleeder resistor is connected to one end of switch V, and the other end of switch V is connected to the negative electrode of the energy storage capacitor to form a bleeder branch circuit;

[0011] The positive electrode of the energy storage capacitor is connected to one end of switch V3, the other end of switch V3 is connected to one end of the welding transformer, the other end of the welding transformer is connected to one end of switch V2, and the other end of switch V2 is connected to the negative electrode of the energy storage capacitor to form a demagnetization branch circuit.

[0012] Preferably, the discharge branch circuit is connected to a voltage sampling circuit for sampling the voltage of the energy storage capacitor when the discharge branch circuit is turned on.

[0013] Preferably, the demagnetization branch circuit is connected to a current sampling circuit for sampling the current of the welding transformer when the demagnetization branch circuit is turned on.

[0014] Preferably, the single-direction discharge circuit of the inverter energy storage welding machine further includes a CPU, which is respectively connected to the charging branch circuit, switch V, the voltage sampling circuit, switch V1, switch V², switch V3, switch V4 and the current sampling circuit, and is used to control the switching between the charging branch circuit, the discharge branch circuit, the bleeder branch circuit and the demagnetization branch circuit.

[0015] The present utility model provides a single-direction discharge circuit for an inverter energy storage welding machine, which automatically demagnetizes the welding transformer after the current welding is completed, solves the magnetization problem of the welding transformer during single-direction discharge, realizes the single-direction discharge of the inverter energy storage welding machine, improves the overall process integrity, and prolongs the service life of all working materials. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the forward discharge circuit of the welding transformer of the prior art inverter energy storage welding machine;

[0017] Figure 2 It is a schematic diagram of the reverse discharge circuit of the welding transformer of the prior art inverter energy storage welding machine;

[0018] Figure 3 It is a schematic diagram of nut welding in the prior art;

[0019] Figure 4 It is a schematic diagram of a single-direction discharge circuit for an inverter energy storage welding machine provided by an embodiment of the present utility model. Detailed Embodiments

[0020] The present utility model will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present utility model and not to limit the scope of the present utility model. In addition, it should be understood that after reading the content taught by the present utility model, those skilled in the art can make various changes or modifications to the present utility model, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0021] As Figure 4 shown, an embodiment of the present utility model provides a unidirectional discharge circuit for an inverter energy storage welding machine, including a charging circuit, a discharging circuit, a current and voltage sampling circuit, a demagnetizing circuit, and a CPU. The specific working principle is as follows:

[0022] 1. Welding.

[0023] First, the CPU issues a charging command, and through the charging circuit, the rectifying circuit is controlled to charge the energy storage capacitor. During charging, V, V1, V2, V3, and V4 are all in the off state. After charging is completed, V1 and V4 are turned on, V2 and V3 remain off, and the current flows through the positive of the capacitor, V1, the welding transformer, V4, and the negative of the capacitor to form a loop. The voltage of the welding transformer is positive at the top and negative at the bottom, and the workpiece is discharged for welding. When the welding time reaches, V1 and V4 are turned off, and the welding discharge is completed. During the time when V1 and V4 are turned on, the CPU samples the capacitor voltage and records the area of the capacitor voltage during the conduction time of V1 and V4, that is, the area of the voltage applied to the welding transformer when it is energized.

[0024] 2. Demagnetization.

[0025] The demagnetizing voltage during demagnetization should not be too high. Through repeated experiments, it is known that a demagnetizing voltage of about 80V is more ideal. If the demagnetizing voltage is too high, it is easy to cause the secondary voltage of the welding transformer to be too high, and it is easy to have a slight sparking phenomenon when replacing the workpiece. If the demagnetizing voltage is too low, the demagnetizing time will be too long.

[0026] After welding is completed, V1, V2, V3, and V4 are all in the off state, the air valve is powered off, the cylinder is in the reset state, and the secondary of the welding transformer is in the open state. The CPU detects the capacitor voltage. If the capacitor voltage is lower than the preset degaussing voltage, the rectifier circuit is controlled by the charging circuit to charge the energy storage capacitor. If the capacitor voltage is higher than the degaussing voltage, V is turned on to open the discharge loop, and the capacitor voltage is released through the resistor R. After the capacitor voltage is consistent with the degaussing voltage, degaussing starts. V1 and V4 continue to be in the off state, and V2 and V3 are turned on. At this time, the secondary of the welding transformer is in the open state, and the current flowing through the welding transformer is small, only the exciting current. The exciting current forms a loop through the positive capacitor, V3, the welding transformer, V2, and the negative capacitor. While V2 and V3 are turned on, the CPU samples the capacitor voltage. When the collected voltage area is equal to the area during welding, it is considered that the degaussing process is completed, and V2 and V3 are turned off, and the transformer degaussing ends.

[0027] Since degaussing is completed during the interval of replacing the workpiece after welding is completed, it has no impact on the entire production rhythm. Through actual use, users have reported good results, perfectly solving the problem of transformer core magnetization caused by unidirectional discharge of the inverter energy storage welder.

Claims

1. A unidirectional discharge circuit for an inverter energy storage welding machine, characterized in that, Including: The charging circuit is electrically connected to the energy storage capacitor through a plurality of diodes in the rectifying circuit to form a charging branch; The positive electrode of the energy storage capacitor is connected to one end of the switch V1, the other end of the switch V1 is connected to one end of the welding transformer, the other end of the welding transformer is connected to one end of the switch V4, and the other end of the switch V4 is connected to the negative electrode of the energy storage capacitor to form a discharging branch; The positive electrode of the energy storage capacitor is connected to one end of the discharging resistor, the other end of the discharging resistor is connected to one end of the switch V, and the other end of the switch V is connected to the negative electrode of the energy storage capacitor to form a discharging branch; The positive electrode of the energy storage capacitor is connected to one end of the switch V3, the other end of the switch V3 is connected to one end of the welding transformer, the other end of the welding transformer is connected to one end of the switch V2, and the other end of the switch V2 is connected to the negative electrode of the energy storage capacitor to form a demagnetizing branch.

2. The unidirectional discharge circuit of an inverter energy storage welding machine according to claim 1, wherein, The discharging branch is connected to the voltage sampling circuit for sampling the voltage of the energy storage capacitor when the discharging branch is turned on.

3. The unidirectional discharge circuit of an inverter energy storage welding machine according to claim 1, wherein The demagnetizing branch is connected to the current sampling circuit for sampling the current of the welding transformer when the demagnetizing branch is turned on.

4. The unidirectional discharge circuit of an inverter energy storage welding machine according to claim 3, wherein, The unidirectional discharging circuit of the inverter energy storage welding machine further includes a CPU, which is respectively connected to the charging branch, the switch V, the voltage sampling circuit, the switch V1, the switch V2, the switch V3, the switch V4 and the current sampling circuit for controlling the switching between the charging branch, the discharging branch, the discharging branch and the demagnetizing branch.

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