CN202780179U

CN202780179U - Overcurrent protection circuit of main circuit of inverter welding machine

Info

Publication number: CN202780179U
Application number: CN 201220520589
Authority: CN
Inventors: 李爱文
Original assignee: ZIBO SHANDA AOTAI ELECTRIC CO Ltd
Current assignee: ZIBO SHANDA AOTAI ELECTRIC CO Ltd
Priority date: 2012-10-11
Filing date: 2012-10-11
Publication date: 2013-03-13
Anticipated expiration: 2022-10-11

Abstract

The utility model belongs to the field of overcurent protection circuits and particularly relates to an overcurrent protection circuit of a main circuit of an inverter welding machine. The overcurrent protection circuit comprises a main transformer of the inverter welding machine and a drive plate, and is characterized in that the main transformer is provided with a current transformer in a connection manner, an output end of the current transformer is provided with a rectifying circuit and a filtering unit in a connection manner, an output end of the filtering unit is provided with a voltage dividing unit, an output end of the voltage dividing unit is connected with a control chip through a voltage follower, and an output end of the control chip is provided with the drive plate in a connection manner. With adoption of simple circuit design, the overcurent protection circuit is reduced in cost, rapid in response, accurate in signal sampling, timely in control and capable of protecting the welding machine more effectively during overcurrent. The overcurent protection circuit disclosed by the utility model is wide in application range, is not only suitable for overcurrent protection of the welding machine but also applicable to all circuits related to current feedback, overcurrent protection and undercurrent protection circuits, and the like.

Description

Inverter type welder main circuit current foldback circuit

Technical field

The utility model belongs to the current foldback circuit field, particularly a kind of inverter type welder main circuit current foldback circuit.

Background technology

At present, the application of inversion transformation technique in Arc Welding Power is very general, and the CO2 gas shielded welding machine of main flow also adopts invertings more now.But the components and parts such as old-fashioned triode, voltage-stablizer, 555 signal sources are generally adopted in most inverter type welder overcurrent protection measures, and components and parts are many and mix, and electromagnetic interference is serious between the wiring board, its stability and accurately to decide be not fine.

The utility model content

According to above the deficiencies in the prior art, the technical problems to be solved in the utility model is: provide a kind of over-current signal picked-up circuit simple, response is fast, and signal is inverter type welder main circuit current foldback circuit accurately.

The technical scheme that its technical problem that solves the utility model adopts is: a kind of inverter type welder main circuit current foldback circuit; the main transformer and the drive plate that comprise inverter type welder; it is characterized in that: main transformer arranges the connection current transformer; the output of current transformer arranges and connects rectification circuit and filter unit; the output of filter unit arranges partial pressure unit; the output of partial pressure unit connects control chip by voltage follower, and the output of control chip arranges the connection drive plate.

The main transformer primary current of inverter type welder induces electric current I through the inductance coil of current transformer _Sense, and with rectification circuit with I _SenseBe integrated into direct current by interchange, be converted to voltage signal by resistance.This signal filters high-frequency signal wherein through filter unit, then enters follower, follower output voltage input control chip through after the dividing potential drop.When this current foldback circuit when major loop gently transships, the signal that collects is delivered to drive plate, the pulse dead band of drive plate gauge tap device increases, and major loop is exported step-down; When this current foldback circuit when major loop heavily transships, the signal that collects is delivered to drive plate, the pulse of drive plate gauge tap device will be closed, and major loop is exported zero setting.

Wherein preferred version is:

Current transformer is passed on the former limit of described main transformer.

Described rectification circuit is the rectifier bridge that Xiao Jite diode D1-D4 consists of, and follower adopts integrated circuit structure.Simplify circuit.

Resistance R 1 and capacitor C in parallel are set between the output of described rectifier bridge, and this output connects follower U1 by resistance R 2, and the output of follower U1 connects the input of control chip.

The beneficial effect that the utility model inverter type welder main circuit current foldback circuit has is: by the connection current transformer is set at main transformer; the output of current transformer arranges and connects rectification circuit, filter unit, partial pressure unit, voltage follower and control chip; the output of control chip arranges the connection drive plate; the design of employing ball bearing made using; reduced cost, be swift in response, signal sampling is accurate; control in time, can be when overcurrent more effective protection welding machine.

Of the present utility model having wide range of applications is not only applicable to the overcurrent protection of welding machine, also relates to current feedback, overcurrent protection, undercurrent protection circuit etc. applicable to all.

Description of drawings

Fig. 1 is circuit theory diagrams of the present utility model;

Among the figure: TH, current transformer D1-D4, diode C, electric capacity R1-R3, resistance U1, follower U2, PWM controller.

The specific embodiment

Below in conjunction with accompanying drawing embodiment of the present utility model is described further:

As shown in Figure 1, main transformer arranges the connection current transformer, the output of current transformer arranges and connects rectification circuit and filter unit, the output of filter unit arranges partial pressure unit, the output of partial pressure unit connects control chip by voltage follower, and the output of control chip arranges the connection drive plate.

Current transformer TH is passed on the former limit of main transformer.Rectification circuit is the rectifier bridge that Xiao Jite diode D1-D4 consists of, and voltage follower adopts the follower U1 of integrated circuit structure.Control chip adopts the PWM controller U2 of UC3846.

Wherein, current transformer TH coil is passed as former limit in the former limit of main transformer for conversion welder, current transformer TH coil secondary 1 connects the anode of diode D1 and the negative electrode of diode D3, current mutual inductor coil secondary 2 connects the negative electrode of diode D4 and the anode of diode D2, the anodic bonding of the anode of diode D3 and diode D4 is to resistance R 1, one end and the ground connection of R3 and capacitor C, the negative electrode of the negative electrode of diode D1 and diode D2 is connected to resistance R 1, the other end of capacitor C also is connected to an end of resistance R 2, the end of the other end contact resistance R3 of resistance R 2 also is connected to No. 1 pin of follower U1, No. 2 pin of follower U1 are connected to No. 8 pin of follower U1 and are connected to No. 4 pin and No. 16 pin of PWM controller U2, No. 11 pin output control voltages of PWM controller U2.

Operation principle and use procedure:

The utility model mainly realizes exporting little electric current and large overcurrent protection.When output current increases suddenly, the induction output of current transformer TH also increases rapidly thereupon, this output obtains a larger effective comparison signal after rectification, sampling filter, voltage division processing, this signal enters respectively No. 4 pin and No. 16 pin of PWM controller U2.In No. 4 pin of PWM controller U2 integrated circuit the PWM comparator is arranged, No. 16 pin is provided with the shutoff level.When shutoff level that this signal arranges less than No. 16 pin, obtain the PWM output signal of a compression pulse width by No. 4 built-in PWM comparators of pin, thereby reduce rapidly the driver output of No. 11 pin of integrated circuit, reduce output current, realize the overcurrent protection of the little electric current of output; When this signal increased to the shutoff level of No. 16 pin settings, integrated circuit U2 directly blocked the driver output of No. 11 pin, and making output current is zero, realizes the overcurrent protection of the large electric current of output.

Claims

1. inverter type welder main circuit current foldback circuit; the main transformer and the drive plate that comprise inverter type welder; it is characterized in that: main transformer arranges the connection current transformer; the output of current transformer arranges and connects rectification circuit and filter unit; the output of filter unit arranges partial pressure unit; the output of partial pressure unit connects control chip by voltage follower, and the output of control chip arranges the connection drive plate.

2. inverter type welder main circuit current foldback circuit according to claim 1, it is characterized in that: current transformer is passed on the former limit of described main transformer.

3. inverter type welder main circuit current foldback circuit according to claim 1 is characterized in that: described rectification circuit is the rectifier bridge that Xiao Jite diode D1-D4 consists of, and voltage follower adopts integrated circuit structure.

4. inverter type welder main circuit current foldback circuit according to claim 3; it is characterized in that: resistance R 1 and capacitor C in parallel are set between the output of described rectifier bridge; this output connects follower U1 by resistance R 2, and the output of follower U1 connects the input of control chip.