CN218555878U

CN218555878U - Electric welding machine control circuit suitable for all power grid voltages

Info

Publication number: CN218555878U
Application number: CN202222637102.7U
Authority: CN
Inventors: 胡宝良; 唐文
Original assignee: Shenzhen Gubang Technology Co ltd
Current assignee: Shenzhen Gubang Technology Co ltd
Priority date: 2022-10-09
Filing date: 2022-10-09
Publication date: 2023-03-03
Anticipated expiration: 2032-10-09

Abstract

The utility model relates to an electric welding control circuit who adapts to all grid voltages, including single-phase rectifier bridge, switching power supply circuit, mains voltage judges the circuit, filter circuit, the filter circuit output with respectively with first voltage clamping diode, second voltage clamping diode electric connection, the primary winding of series connection main transformer between first voltage clamping diode and the second voltage clamping diode, the secondary winding output and the comprehensive decision circuit electric connection of main transformer, comprehensive decision circuit and PWM switching circuit's output electric connection, PWM switching circuit's input is connected with PWM circuit's output, PWM circuit's input and isolation impulse circuit's output end connection, keep apart impulse circuit's input respectively with first power switch pipe, second power switch union coupling. Can cover 220VAC and 380VAC, meet the use of two voltage classes under the condition of not using a relay adopting mechanical contact type switching, and also ensure the normal work in the whole voltage range.

Description

Electric welding machine control circuit suitable for all power grid voltages

Technical Field

The utility model relates to a power control circuit's technical field especially relates to an electric welding control circuit who adapts to all grid voltages.

Background

The domestic patent with the application number of CN201810930067.3 discloses a device for controlling multimedia central controller, which comprises an AC220V/50Hz power supply, a transformer T1, a filtering voltage stabilizing circuit, a voltage rectifying filter circuit, an electric screen power supply control circuit and a device power supply control circuit, wherein the AC220V/50Hz power supply is connected with the transformer T1, the AC220V/50Hz power supply outputs 14.5V and 10V alternating current after passing through the transformer T1, the 14.5V alternating current outputs +12V voltage after passing through the filtering voltage stabilizing circuit, the 10V alternating current outputs 10V voltage after passing through the voltage rectifying filter circuit, the input end of a foolproof plug is respectively connected with the filtering voltage stabilizing circuit, the voltage rectifying filter circuit, the electric screen power supply control circuit and the device power supply control circuit, and is connected with the multimedia central controller through the foolproof plug, thereby supplying power to the multimedia central controller

In actual production, the existing power devices are more in variety according to actual production conditions, but the power devices suitable for high-power high-voltage and high-frequency applications are limited by different materials, manufacturing costs and technologies. The inverter power supply for welding is already mature and applied to the formation and batch production. However, with further development and application of welding power sources, how to reduce the requirements of welding on manual technology and how to make welding more easily achieve high efficiency and high quality basically needs to greatly increase the inverter conversion frequency. As long as the inversion frequency is improved to a certain point, the self-adaptive electrical capacity is relatively improved by one stage in the welding process, and meanwhile, the precise and accurate welding can be improved to control to be completely and effectively embodied on the formation of the welding seam. The basic structure and application of the manual arc welding machine with 220V/50Hz civil power supply and 3-phase 380V power supply. The above patent is not suitable for use in 3-phase 380V power supply environment.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem, the utility model provides an adapt to all mains voltage's electric welding control circuit accomodates at the workshop top when not needing to use, falls the back during use and falls the board of making an uproar with adjacent and be connected, uses more in a flexible way, does not occupy workshop working space simultaneously.

In order to realize the above-mentioned purpose, the utility model provides a device of making an uproar falls for in workshop, including the two single tubes of the biggest pulse width of primary sampling regulation wide voltage circuit of conversion, the two single tubes of the biggest pulse width of primary sampling regulation wide voltage circuit of conversion includes single-phase rectifier bridge, single-phase rectifier bridge and switching power supply circuit's input electric connection, switching power supply circuit's output and mains voltage judge circuit connection, single-phase rectifier bridge and filter circuit electric connection, the filter circuit output with respectively with first voltage clamping diode, second voltage clamping diode electric connection, first voltage clamping diode with the primary winding of series connection main transformer between the second voltage clamping diode, the secondary winding output and the comprehensive decision circuit electric connection of main transformer, comprehensive decision circuit and PWM switching circuit's output electric connection, PWM switching circuit's input is connected with PWM circuit's output, PWM circuit's input and isolation impulse circuit's output end connection, isolation impulse circuit's input is connected with first power switch pipe, second power switch pipe respectively.

Furthermore, the filter circuit comprises a first capacitor, a first filter capacitor, a second filter capacitor, a first resistor and a second resistor, the first capacitor is connected in parallel with the single-phase rectifier bridge, the first filter capacitor is connected in series with the second filter capacitor, the first resistor is connected in series with the second resistor, and the cathode of the first filter capacitor and the anode of the second filter capacitor are connected with the serial connection position of the first resistor and the second resistor through a lead.

Further, the switching power supply circuit is connected in parallel with the filter circuit.

Further, an emitter of the first power switch tube is connected to the first input end of the isolation push circuit, and an emitter of the second power switch tube is connected to the second input end of the isolation push circuit.

Further, the PWM circuit includes a UC3846 chip and an external circuit, where the UC3846 chip is electrically connected to the external circuit.

Further, a first output end of the isolation pushing circuit is connected to an E1 port of the UC3846 chip, and a second output end of the isolation pushing circuit is connected to an E2 port of the UC3846 chip.

Compared with the prior art, the beneficial effects of the utility model reside in that:

the utility model can adopt a plurality of pipes in parallel based on the characteristics of circuit composition, thus easily realizing the parallel superposition of current and the arbitrary promotion of output current; the single-tube IGBT can realize arbitrary parallel superposition and arbitrary composition of output current capacity, can cover civil-grade working voltage (220 VAC) and industrial-grade working voltage (380 VAC), meets the use of two voltage grades under the condition of not using a relay adopting mechanical contact type switching, and also enables the whole voltage category to work normally.

For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.

Drawings

Fig. 1 is a circuit diagram of the present invention;

fig. 2 is a functional diagram of the UC3846 pin and an internal component circuit diagram of the present invention;

fig. 3 is a circuit diagram of a PWM circuit composed of UC 3846.

In the figure: 1. a switching power supply circuit; 2. a power supply voltage judging circuit; 3. a filter circuit; 4. a comprehensive decision circuit; 5. a PWM switching circuit; 6. a PWM circuit; 601. UC3846 chip; 602. an external circuit; 7. an isolation push circuit; 701. a first input terminal; 702. a second input terminal; 703. a first output terminal; 704. a second output terminal.

Detailed Description

The conception, specific structure and technical effects of the present invention will be described clearly and completely with reference to the accompanying drawings and embodiments, so as to fully understand the objects, aspects and effects of the present invention. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It is to be understood that, unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any combination of one or more of the associated listed items.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element of the same type from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure.

In the prior art, the control circuit of various switch circuits has the following advantages and disadvantages:

the switching power supply circuit with the standard single tube excitation form is characterized by simple circuit, wide voltage working range, high voltage level of a power switching tube for pushing the exciting current of a primary coil, low conversion efficiency compared with the following three circuits, suitability for smaller power and great adoption of the switching power supply.

The half-bridge inverter circuit utilizes the bipolar excitation of the inverter isolation transformer, has high electromagnetic conversion efficiency, and has obvious defects in response speed of output electrical parameter adjustment. When the half-bridge inverter circuit is generally applied to welding products, the half-bridge inverter circuit is limited to a manual arc welding characteristic-reducing power supply and cannot be competent for a power supply with high dynamic characteristics.

The advantages and disadvantages of the push-pull type inverter power circuit are mainly limited by the technology of the inverter isolation transformer, and the push-pull type inverter power circuit is not suitable for a larger power mode.

The H-bridge inverter circuit completely overcomes the dynamic characteristic defect caused by the capacitor in the half-bridge inverter, but on one hand, a module packaged IGBT with larger current cannot realize the ultrasonic frequency range inverter switch, and the loss exceeds the packaging thermal standard value; secondly, the existing IGBT single tube packaging enables the single wafer process technology to achieve enough reduction of loss and form response speed suitable for high frequency.

A voltage-multiplying rectification form circuit which forms a full-wave voltage-multiplying rectification form; the 270 VAC-540 VAC end is used as a high-voltage segment, and the relay is prohibited to be conducted, so that a conventional rectification circuit form is formed. Therefore, the direct-current output voltage is consistent when the high-voltage end and the low-voltage end are achieved, but the limitation is generated after the relay is used, and firstly, the relay device has the capability of adapting to high-voltage large current; secondly, the capacity required by the charging and discharging of the electrolytic capacitor is greatly improved; thirdly, the reverse voltage withstand voltage value of the rectifier bridge is improved; and fourthly, the voltage-doubling rectifying circuit is only suitable for a single-phase power supply circuit.

Compared with a voltage-multiplying rectification type circuit, the half-bridge inversion and main transformer tap double-voltage inversion circuit has the defects that the form is larger, and the voltage level borne by a first relay is high; the second higher the frequency of the voltage carried on its relay; the third applicable output power is limited to a range of amounts.

Referring to fig. 1-3, a control circuit of a welding machine suitable for all power grid voltages comprises:

the primary level sampling and maximum pulse width adjusting double-monotube forward conversion wide voltage circuit comprises a single-phase rectifier bridge BG1, the single-phase rectifier bridge BG1 is electrically connected with an input end of a switch power circuit 1, an output end of the switch power circuit 1 is connected with a power voltage judging circuit 2, the single-phase rectifier bridge BG1 is electrically connected with a filter circuit 3, an output end of the filter circuit 3 is electrically connected with a first voltage clamping diode D3 and a second voltage clamping diode D4 respectively, a primary winding of a main transformer T1 is connected in series between the first voltage clamping diode D3 and the second voltage clamping diode D4, an output end of a secondary winding of the main transformer T1 is electrically connected with a comprehensive judging circuit 4, the comprehensive judging circuit 4 is electrically connected with an output end of a PWM switching circuit 5, an input end of the PWM switching circuit 5 is connected with an output end of the PWM circuit 6, an input end of the PWM circuit 6 is connected with an output end of an isolation pushing circuit 7, and an input end of the isolation pushing circuit 7 is connected with a first power switch Q1 and a second power switch Q2 respectively.

The switching power supply circuit 1, the power supply voltage judging circuit 2, the comprehensive judging circuit 4, the PWM switching circuit 5, and the isolation pushing circuit 7 are all conventional circuits, and therefore, they will not be described.

According to the technical scheme, the diodes from the primary coil of the inverter isolation transformer to the switching tube of the power supply and the ground are added relative to the single-tube exciting circuit, a reliable primary coil voltage clamping position is formed, and the power switching tube is synchronously switched on and off and is consistent with the working efficiency of the single tube. However, the two power switch tubes (Q1 and Q2) are based on the intervention of a voltage clamping diode (D3/D4), the voltage level does not exceed the direct-current power supply voltage, and the power switch tubes are in an absolute safe working environment. Meanwhile, the voltage clamping diode leads the potential of the primary coil to the power supply end when the primary coil is induced to the secondary coil, so that the energy utilization rate is improved, and the overall conversion efficiency is greatly improved compared with that of a single-tube mode. The power switch tubes are synchronously switched on and off, and dead time setting is not needed compared with bridge type and push-pull type working modes. The possibility of damage caused by the fact that double tubes are simultaneously conducted to direct current is eliminated, and potential safety hazards of the power switch tube are smaller.

The main circuit is in the form of a double-single-tube anode excitation and diode clamping inverter circuit, the working modes of single-tube IGBTs in the circuit are completely consistent, and the circuit error formed in a high-frequency switch current loop between parallel tubes can be received. Because of the circuit characteristics, the power tube has enough on-off time length and the working time sequence is all the same; small errors formed between each other can be offset based on synchronous switching, so that the defects caused by parallel connection are avoided. Based on the characteristics of circuit composition, multiple tubes can be connected in parallel, current parallel superposition can be easily realized, and the working voltage can cover civil-grade working voltage (220 VAC) and industrial-grade working voltage (380 VAC), so that the use of two voltage grades can be met under the condition that a relay adopting mechanical contact type switching is not used, and the whole voltage category can normally work.

The filter circuit 3 comprises a first capacitor C1, a first filter capacitor E1, a second filter capacitor E2, a first resistor R1 and a second resistor R2, the first capacitor C1 is connected with the single-phase rectifier bridge BG1 in parallel, the first filter capacitor E1 is connected with the second filter capacitor E2 in series, the first resistor R1 is connected with the second resistor R2 in series, and the cathode of the first filter capacitor E1 and the anode of the second filter capacitor E2 are connected with the series connection of the first resistor R1 and the second resistor R2 through wires.

The switching power supply circuit 1 is connected in parallel with the filter circuit 3.

The emitter of the first power switch Q1 is connected to the first input terminal 701 of the isolation push circuit 7, and the emitter of the second power switch Q2 is connected to the second input terminal 702 of the isolation push circuit 7.

As shown in fig. 2 and fig. 3, the PWM circuit 6 includes a UC3846 chip 601 and an external circuit 602, and the UC3846 chip 601 is electrically connected to the external circuit 602.

The first output end of the isolation pushing circuit is connected with an E1 port (namely 5 interfaces: E/A +) of the UC3846 chip, and the second output end of the isolation pushing circuit is connected with an E2 port (namely 6 interfaces: E/A-) of the UC3846 chip.

When the external input voltage is too high or the voltage of the output end is too high, an output voltage acquisition value formed by R9, R10, R11 and C6 is input to the negative phase input end of the comparator, the voltage value is high Yu Bijiao, the positive phase input end of the comparator sets voltage, and the comparator outputs low level. And a pin 2 (Vg) of the optical coupler OP1 is in a low level state, and the optical coupler is switched on. The rear-stage phototransistor is switched on, the voltage of the 4 pins is high level, the capacitor CBH and the diode DBH output a positive pulse to be applied to the 16 pins, and a wave-sealing effect is formed. Meanwhile, the 4-pin high level of the optocoupler OP1 also prompts the transistor QBH to be conducted, but based on the acceleration of CBH, the transistor is delayed from being conducted by the thyristor a little later, and the wave-sealing effect is still formed; namely, 11-pin (AOUT) positive pulses and 14-pin (BOUT) negative pulses generated by UC3846 are uniformly compressed to the minimum. After the transistor is conducted, the conduction voltage drop of the thyristor for maintaining conduction is eliminated, and the thyristor can be cut off and conducted. Thus, the wave-sealing effect can be unlocked and the pulse output can be recovered.

The effect of formation is: after the whole machine is started, when the no-load voltage of the output end exceeds a certain limit value, a wave-sealing period (the time length of which is determined by the ratio of R16\ R17) is formed, and the voltage of the output end is reduced in the period; and after pulse output is recovered again, the voltage of the output end is subjected to wave sealing again when exceeding the limit value, and the reciprocating cycle is performed once. The actual achievement of the no-load voltage is limited to a set value. When the welding is started, the phenomenon of excess voltage can not occur.

By utilizing the functional circuit design, primary overvoltage protection and secondary overvoltage protection are achieved, and the standard that secondary no-load voltage can exceed national standard safety voltage is formed.

Meanwhile, after the whole machine is started up through the PWM circuit 6, when the no-load voltage of the output end exceeds a certain limit value (set by an external comparator), a wave-blocking period (the time length of which is determined by the ratio of R16/R17) is formed, and the voltage of the output end is reduced in the period; and after pulse output is recovered again, the voltage of the output end is subjected to wave sealing again when exceeding the limit value, and the reciprocating cycle is performed once. The actual achievement of the no-load voltage is limited to a set value. When the welding is started, the phenomenon of excess voltage can not occur.

Claims

1. A control circuit of an electric welding machine adapting to all power grid voltages is characterized by comprising a primary-secondary sampling and adjusting maximum pulse width double-single-tube forward wide voltage conversion circuit, the primary and secondary sampling maximum pulse width double-single tube forward transformation wide voltage circuit comprises a single-phase rectifier bridge (BG 1), the single-phase rectifier bridge (BG 1) is electrically connected with the input end of the switch power supply circuit (1), the output end of the switch power supply circuit (1) is connected with the power supply voltage judging circuit (2), the single-phase rectifier bridge (BG 1) is electrically connected with the filter circuit (3), the output end of the filter circuit (3) is electrically connected with the first voltage clamping diode (D3) and the second voltage clamping diode (D4) respectively, a primary winding of a main transformer (T1) is connected in series between the first voltage clamping diode (D3) and the second voltage clamping diode (D4), the output end of the secondary winding of the main transformer (T1) is electrically connected with the comprehensive judgment circuit (4), the comprehensive judgment circuit (4) is electrically connected with the output end of the PWM switching circuit (5), the input end of the PWM switching circuit (5) is connected with the output end of the PWM circuit (6), the input end of the PWM circuit (6) is connected with the output end of the isolation pushing circuit (7), the input end of the isolation pushing circuit (7) is respectively connected with the first power switch tube (Q1) and the second power switch tube (Q2).

2. The electric welding machine control circuit capable of adapting to all power grid voltages according to claim 1, wherein the filter circuit (3) comprises a first capacitor (C1), a first filter capacitor (E1), a second filter capacitor (E2), a first resistor (R1) and a second resistor (R2), the first capacitor (C1) is connected with the single-phase rectifier bridge (BG 1) in parallel, the first filter capacitor (E1) is connected with the second filter capacitor (E2) in series, the first resistor (R1) is connected with the second resistor (R2) in series, and a cathode of the first filter capacitor (E1) and an anode of the second filter capacitor (E2) are connected with a series connection of the first resistor (R1) and the second resistor (R2) through a lead.

3. Control circuit of electric welding machine adapted to all mains voltages according to claim 2, characterized in that said switching power supply circuit (1) is connected in parallel with said filtering circuit (3).

4. A control circuit of a welder adapted to all mains voltages according to claim 3, characterized in that the emitter of the first power switch (Q1) is connected to the first input (701) of the isolation push circuit (7) and the emitter of the second power switch (Q2) is connected to the second input (702) of the isolation push circuit (7).

5. The electric welding machine control circuit suitable for all power grid voltages as claimed in claim 4, wherein said PWM circuit (6) comprises a UC3846 chip (601) and an external circuit (602), said UC3846 chip (601) being electrically connected to said external circuit (602).

6. A control circuit of electric welding machine adapting to all network voltages as claimed in claim 5, characterized in that the first output terminal (703) of said isolation push circuit (7) is connected to the E1 port of said UC3846 chip (601), and the second output terminal (704) of said isolation push circuit (7) is connected to the E2 port of said UC3846 chip (601).