Hybrid power welding machine and welding system with same

Abstract

The utility model discloses a hybrid welding machine and a welding system with the same, the hybrid welding machine comprises an AC input interface, an AC-DC conversion circuit, a full bridge circuit, a BUCK circuit, a detection circuit, a controller, a controllable switch and a battery pack, the input end of the AC-DC conversion circuit is connected with an external AC power supply through the AC input interface; the output end of the BUCK circuit is configured to be connected with welding equipment; the AC-DC conversion circuit, the full-bridge circuit and the BUCK circuit are connected in sequence to form an AC power supply branch; the battery pack, the controllable switch and the BUCK circuit are connected in sequence to form a direct current power supply branch; the detection circuit is configured to detect an electric signal on the alternating current power supply branch, the input end of the controller is connected with the detection circuit, and the output end of the controller is connected with the enabling end of the controllable switch; when the detection circuit detects that the electric signal on the alternating current power supply branch is zero, the controller sends an enable signal to the controllable switch.

Description

Technical Field

[0001] The utility model relates to the field of power equipment, in particular to a hybrid welding machine and a welding system having the same. Background Art

[0002] In the traditional welding field, welding equipment usually relies on alternating current (AC) power supply, which limits the mobility and flexibility of welding operations, especially in outdoor or remote areas without a stable power supply. In addition, for working environments that require frequent movement of the operation point, such as construction sites, vehicle repairs, or temporary emergency repair tasks, the dragging of cables is not only inconvenient but also may pose safety hazards.

[0003] To overcome these limitations, some welding equipment has begun to use batteries as a power source to improve its portability and adaptability, which has solved some problems to a certain extent, but it can only be used as a partial supplement in places without commercial power and does not have universal applicability.

[0004] Battery-powered welding equipment usually faces problems such as short battery life, long charging time, high battery cost, and complex maintenance, and can only be used for emergency repairs in outdoor places without alternating current. These factors limit the wide application of battery-powered welding equipment.

[0005] The disclosure of the above background art content is only used to assist in understanding the concept and technical solution of the present application, and it does not necessarily belong to the prior art of the present application, nor will it necessarily give technical guidance; in the case where there is no clear evidence that the above content has been publicly disclosed before the filing date of the present application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. Summary of the Utility Model

[0006] The purpose of the present utility model is to provide a hybrid welding machine, which is designed to be powered by an alternating current power supply and can also perform welding operations by battery power in the absence of an alternating current power supply, improving the applicability and flexibility of the welding equipment so that it can adapt to more types of working environments.

[0007] To achieve the above object, the technical solution adopted by the present utility model is as follows:

[0008] A hybrid welding machine includes an AC input interface, an AC-DC conversion circuit, a full-bridge circuit, a BUCK circuit, a detection circuit, a controller, a controllable switch, and a battery pack. Among them, the input end of the AC-DC conversion circuit is connected to an external alternating current power supply through the AC input interface; the output end of the BUCK circuit is configured to be connected to welding equipment;

[0009] The AC-DC conversion circuit, the full-bridge circuit, and the BUCK circuit are connected in sequence to form an AC power supply branch;

[0010] The battery pack, the controllable switch, and the BUCK circuit are connected in sequence to form a DC power supply branch;

[0011] The input end of the detection circuit is connected to the output end of the AC-DC conversion circuit, the input end of the controller is connected to the output end of the detection circuit, and the output end of the controller is connected to the enable end of the controllable switch.

[0012] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the BUCK circuit includes a first power switch, a first diode, and an inductor. The emitter of the first power switch is respectively connected to the full-bridge circuit and the controllable switch, and the collector of the first power switch is respectively connected to the negative electrode of the first diode and one end of the inductor;

[0013] The other end of the inductor is configured to be connected to the welding equipment;

[0014] The positive electrode of the first diode is respectively connected to the full-bridge circuit and the negative electrode of the battery pack.

[0015] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the duty cycle of the first power switch of the BUCK circuit is between 40% and 60%;

[0016] The duty cycle of the full-bridge circuit is between 40% and 60%.

[0017] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, a body diode is connected in parallel with the first power switch, and the conduction direction of the body diode is the same as that of the first diode.

[0018] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the battery of the battery pack is a storage battery;

[0019] The controllable switch is configured to conduct operably when the first power switch is turned off, so that the AC-DC conversion circuit, the full-bridge circuit, and the battery pack form a charging loop.

[0020] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the detection circuit includes a resistor and an optocoupler. The resistor is connected to the positive electrode of the primary side of the optocoupler, and the secondary side of the optocoupler is connected to the input end of the controller;

[0021] When the AC input interface accesses an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a high-level signal to a low-level signal; when the AC input interface disconnects the external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a low-level signal to a high-level signal;

[0022] Alternatively, when the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a low-level signal to a high-level signal; when the AC input interface disconnects from the external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a high-level signal to a low-level signal.

[0023] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the controller is an MCU;

[0024] Alternatively, the controller is configured with a comparator. One of the non-inverting input terminal and the inverting input terminal of the comparator is connected to the voltage of the secondary side of the optocoupler, and the other is connected to a reference voltage. The output terminal of the comparator is connected to the enable terminal of the controllable switch.

[0025] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, when the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a high-level signal to a low-level signal; the non-inverting input terminal of the comparator is configured to be connected to the voltage of the secondary side of the optocoupler, and its inverting input terminal is configured to be connected to a reference voltage;

[0026] Alternatively, when the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a low-level signal to a high-level signal; the non-inverting input terminal of the comparator is configured to be connected to a reference voltage, and its inverting input terminal is configured to be connected to the voltage of the secondary side of the optocoupler.

[0027] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the AC-DC conversion circuit includes four diodes and a capacitor;

[0028] The full-bridge circuit includes four power switches, a transformer, and two diodes.

[0029] According to another aspect of the present invention, the present invention provides a welding system, including a welding device and the hybrid power welding machine as described above. The welding device is connected to the output terminal of the BUCK circuit of the hybrid power welding machine.

[0030] The beneficial effects brought by the technical solutions provided by the present invention are as follows:

[0031] a. Combining the advantages of AC power supply and battery power supply: The designed welding device can be powered by an AC power supply and can also perform welding operations by battery power supply in the absence of an AC power supply, significantly improving the applicability and flexibility of the welding device, enabling it to adapt to more types of working environments;

[0032] b. It is possible to control and adjust the duty cycle of the power switches in the full-bridge circuit and the BUCK circuit, enabling them to operate in the optimal efficiency range and reducing device losses.

[0033] c. When the welding state is off, it is possible to control the full-bridge circuit to operate in a constant voltage and constant current state, allowing the external AC power supply to charge the battery pack and saving an additional battery charger. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 Schematic diagram of the basic framework of a hybrid welding machine provided for an exemplary embodiment of the present invention;

[0036] Figure 2 Schematic diagram of the circuit structure of a hybrid welding machine provided for an exemplary embodiment of the present invention;

[0037] Figure 3 Schematic diagram of the structure of the charging branch circuit provided for an exemplary embodiment of the present invention;

[0038] Figure 4 For removing the BUCK circuit from Figure 1 Schematic diagram of the basic framework of the hybrid welding machine after removing the AC power supply branch. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To enable those skilled in the art to better understand the technical solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] It should be noted that in the description and claims of the present utility model and the above-mentioned drawings, terms such as "first", "second", etc. are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment comprising a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or equipment.

[0041] In an embodiment of the present utility model, a hybrid welding machine is provided, as Figure 1 shown. The welding machine includes an AC input interface, an AC-DC conversion circuit, a full-bridge circuit, a BUCK circuit, a detection circuit, a controller, a controllable switch and a battery pack. Among them, the input end of the AC-DC conversion circuit is connected to an external AC power supply through the AC input interface; the output end of the BUCK circuit is configured to be connected to a welding device;

[0042] The AC-DC conversion circuit, the full-bridge circuit and the BUCK circuit are connected in sequence to form an AC power supply branch; the AC / DC conversion circuit converts the input AC power supply into direct current, and the full-bridge circuit further adjusts the voltage and current characteristics of the direct current; the BUCK circuit is used to generate a DC output power supply suitable for welding / cutting processes.

[0043] The battery pack, the controllable switch and the BUCK circuit are connected in sequence to form a DC power supply branch;

[0044] The input end of the detection circuit is connected to the output end of the AC-DC conversion circuit, and it is configured to detect the electrical signal on the AC power supply branch. The input end of the controller is connected to the output end of the detection circuit, and the output end of the controller is connected to the enable end of the controllable switch;

[0045] The circuit working principle of the present invention is as follows: when the detection circuit detects that the electrical signal on the AC power supply branch is zero, the controller sends an enable signal to the controllable switch. The controllable switch is controlled by the controller and controls the closing, conduction or disconnection of the controllable switch according to the detection result of the detection circuit; the battery pack is used to provide DC power when the controllable switch is closed and conducting. The controller can adopt some typical processing chips such as an MCU, or can also be implemented by building a hardware circuit, which will be described in detail below.

[0046] The circuit structures of each module are described below:

[0047] See Figure 2 , the AC-DC conversion circuit includes diode D1, diode D2, diode D3, diode D4 and capacitor C1. Diodes D1 and D2 with the same conduction direction are connected in series to form a first branch, and diodes D3 and D4 with the same conduction direction are connected in series to form a second branch. The first branch, the second branch and capacitor C1 are connected in parallel; the positive pole of the AC power supply is connected to the connection point of diodes D1 and D2, and the negative pole is connected to the connection point of diodes D3 and D4.

[0048] See Figure 2 , the full-bridge circuit includes power switches Q1, Q2, Q3, Q4, transformer T1, diode D5 and diode D6. Power switches Q1 and Q2 with the same conduction direction are connected in series to form a third branch, and power switches Q3 and Q4 with the same conduction direction are connected in series to form a fourth branch. The third branch and the fourth branch are connected in parallel; one end of the primary side of transformer T1 is connected to the connection point of power switches Q1 and Q2, and the other end of the primary side is connected to the connection point of power switches Q3 and Q4. There are two series-connected winding coils on the secondary side of transformer T1. The two winding coils are respectively connected to the positive poles of diodes D5 and D6, and the negative pole of diode D5 is connected to the negative pole of diode D6. The connection point of the negative poles of diode D5 / diode D6 and the two winding coils constitutes the output end of the full-bridge circuit.

[0049] See Figure 2 , the BUCK circuit includes first power switch Q5, first diode D7 and inductor L1. The emitter of the first power switch Q5 is respectively connected to the full-bridge circuit (the negative pole of diode D5 / diode D6) and controllable switch K1. The collector of the first power switch Q5 is respectively connected to the negative pole of the first diode D7 and one end of the inductor L1;

[0050] The other end of the inductor L1 is configured to be connected to a welding device (not shown);

[0051] The positive pole of the first diode D7 is respectively connected to the full-bridge circuit (the connection point of the two winding coils) and the negative pole of battery pack B1. The positive pole of battery pack B1 is connected to the negative pole of diode D5 / diode D6 through controllable switch K1.

[0052] As Figure 2As shown, a body diode is connected in parallel with the first power switch Q5, and the conduction direction of the body diode is the same as that of the first diode D7. In this embodiment, the battery of the battery pack is a rechargeable battery; when the welding device is turned off (the first power switch is disconnected) and the AC power supply is in the connected state, the controllable switch K1 can be manually operated to make it closed and conducting. At this time, the AC power supply charges the battery pack, that is, the AC-DC conversion circuit, the full-bridge circuit and the battery pack form a charging circuit.

[0053] As Figure 2 shown, the detection circuit includes a resistor R1 and an optocoupler U1. The resistor R1 is connected to the positive terminal of the primary side of the optocoupler U1, and the secondary side of the optocoupler U1 is connected to the input terminal of the controller; in one embodiment, by default, the output of the optocoupler U1 is pulled up to the high level state. When the AC power supply is connected, the current passes through the resistor R1 to make the primary side of the optocoupler U1 work, and then the secondary side of the optocoupler conducts, that is, it switches from the high level state to the low level state, and the controller receives the low level signal. Therefore, the controller can judge whether the AC power supply is connected according to the high and low level signals output by the optocoupler: when the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a high level signal to a low level signal; when the AC input interface disconnects the external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a low level signal to a high level signal.

[0054] The present invention does not limit that the output of the optocoupler U1 is pulled up to the high level state by default. In other embodiments, by default, the output of the optocoupler U1 is at the low level. When the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a low level signal to a high level signal; when the AC input interface disconnects the external AC power supply, the signal output from the secondary side of the optocoupler to the controller returns from a high level signal to a low level signal.

[0055] The present invention does not limit that the controller is an MCU and the implementation manner of judging whether the AC power supply is connected through a program. The present invention can also adopt a hardware circuit implementation manner to control the controllable switch K1:

[0056] The controller is configured with a comparator. For an embodiment where the output of the optocoupler U1 is pulled up to a high level by default, the non-inverting input terminal of the comparator is configured to access the secondary side voltage of the optocoupler, and its inverting input terminal is configured to access a reference voltage. The output terminal of the comparator is connected to the enable terminal of the controllable switch. When an external AC power supply is connected, the voltage accessed by the non-inverting input terminal decreases to be lower than the reference voltage, so the comparator outputs a low level, and the controllable switch K1 cannot conduct; conversely, when the external AC power supply is disconnected, the secondary side of the optocoupler resumes to a high level, the voltage accessed by the non-inverting input terminal is higher than the reference voltage, the comparator outputs a high level, and the controllable switch K1 receives the enable signal output by the comparator and conducts.

[0057] For an embodiment where the output of the optocoupler U1 is at a low level by default, the non-inverting input terminal of the comparator is configured to access a reference voltage, and its inverting input terminal is configured to access the secondary side voltage of the optocoupler. The output terminal of the comparator is connected to the enable terminal of the controllable switch. When an external AC power supply is connected, the secondary side of the optocoupler is pulled up to a high level, the voltage accessed by the inverting input terminal is higher than the reference voltage, so the comparator outputs a low level, and the controllable switch K1 cannot conduct; conversely, when the external AC power supply is disconnected, the secondary side of the optocoupler resumes to a low level, the voltage accessed by the inverting input terminal is lower than the reference voltage, the comparator outputs a high level, and the controllable switch K1 receives the enable signal output by the comparator and conducts.

[0058] When the welding device is in the welding state, the detection circuit detects whether the external AC power supply is connected. As described above, if the external power supply is connected, the controllable switch K1 cannot conduct, and the welding device is powered by the AC power supply. Figure 2 The voltage at the mid-node 1 is 300V (assuming the input is a 220V AC power supply), the turns ratio of the primary and secondary windings of the transformer is 2:1, the controllable switch K1 remains in the off state, and the full-bridge conversion works in the constant voltage state, so that Figure 2 the voltage at the mid-node 2 is maintained at 70V. At this time, the duty cycle of the power switch in the full-bridge circuit is constant at about 50% (40% to 60%, or 45% to 55%), working in the interval of the best efficiency, and then is adjusted and output through the BUCK circuit. For manual welding, the welding arc voltage is usually between 25 and 40V, and the control duty cycle of the BUCK circuit also changes at about 50% (40% to 60%, or 45% to 55%), which is also the interval of the best efficiency.

[0059] If the AC power supply is not connected and the power is provided by the battery, assuming the battery voltage is 70V, the controller closes the controllable switch K1, and the battery directly outputs through the BUCK circuit. The control duty cycle of the BUCK circuit also changes at about 50% (40% to 60%, or 45% to 55%), and the working efficiency is the highest.

[0060] Users can use the welding machine outdoors, in remote areas, or at temporary job sites without a stable AC power supply, without worrying about power limitations; or in places with AC power, directly connect to the AC power and work continuously for a long time, greatly improving the flexibility and adaptability of welding work. The hybrid welding machine of this embodiment reduces the dependence on external power supplies. Especially in the case of frequently changing job locations, it can reduce the additional costs caused by power connection, cable layout, etc.

[0061] When the welding device turns off the welding state, it detects whether the AC power supply is connected. If it is connected, the AC power supply can charge the rechargeable battery of the battery pack. Figure 2 The voltage at the middle node 1 is 300V (assuming the input is a 220V AC power supply), the turns ratio of the primary and secondary windings of the transformer is 2:1, and the controller closes the controllable switch K1 (or manually triggers the controller to close the controllable switch K1), and the full-bridge circuit operates in a constant current and constant voltage state. When the battery is not charged, the full-bridge circuit operates in a constant voltage state, making Figure 2 The voltage at the middle node 2 is constantly maintained at 70V (assuming the battery voltage ≤ 70V); when the battery is charging, the full-bridge circuit operates in a constant current state, Figure 2 The voltage at the middle node 2 is adaptively adjusted according to the voltage of the battery, and the magnitude of the constant current value can be adjusted according to the battery voltage. For example, when the battery voltage is low, a small current is used for charging; before the battery voltage approaches the constant voltage value, a large current is used for charging; when the battery voltage approaches the constant voltage value, a small current is used for charging again. The specific magnitude of the charging current in each stage of this three-stage charging method depends on the specifications of the battery used.

[0062] The opening or closing of the welding state of the above-mentioned welding device is realized by the working switch of the welding device: the working switch is manually operated to send a trigger signal or stop sending a trigger signal to the controller. If the controller receives the trigger signal it sends, the controller controls the operation according to the mode of opening the welding state.

[0063] In one embodiment, as Figure 3 shown, a DC / DC module can also be connected in series between the AC / DC module and the battery pack to charge the battery pack separately. The advantage of this is that as long as there is AC access, the battery pack can be charged without caring about whether the welding state is turned on. Among them, the DC / DC module can be topologies such as flyback, forward, push-pull, half-bridge, full-bridge, LLC, PFC, etc.

[0064] In one embodiment, as Figure 4As shown, the full-bridge converter can also be directly used as the welding output. The battery pack is directly connected in parallel to the output terminal after passing through the controllable switch K1 and the BUCK circuit. The principle of its control method is the same as the above. When there is alternating current, K1 is disconnected and the BUCK circuit does not participate in the regulation; when there is no alternating current, the working path is the same as that of Figure 1 The working path is the same. The advantage of this circuit is that the working paths of AC power supply and battery power supply are completely separated from each other without interference, and the control is simple.

[0065] In an embodiment of the present invention, a welding system is provided, which includes a welding device and the hybrid power welding machine as described above. The welding device is connected to the output terminal of the BUCK circuit of the hybrid power welding machine.

[0066] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0067] The above description is only the specific implementation manners of the present application. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A hybrid welding machine, characterized in that: It includes an AC input interface, an AC-DC conversion circuit, a full-bridge circuit, a BUCK circuit, a detection circuit, a controller, a controllable switch and a battery pack, wherein the input end of the AC-DC conversion circuit is connected to an external AC power source through the AC input interface; the output end of the BUCK circuit is configured to be connected to a welding device; The AC-DC conversion circuit, the full-bridge circuit, and the BUCK circuit are connected in sequence to form an AC power supply branch; The battery pack, the controllable switch, and the BUCK circuit are connected in sequence to form a DC power supply branch; The input end of the detection circuit is connected to the output end of the AC-DC conversion circuit, the input end of the controller is connected to the output end of the detection circuit, and the output end of the controller is connected to the enable end of the controllable switch.

2. The hybrid welding machine according to claim 1, characterized in that: The BUCK circuit includes a first power switch, a first diode and an inductor, wherein the emitter of the first power switch is connected to the full-bridge circuit and the controllable switch respectively, and the collector of the first power switch is connected to the cathode of the first diode and one end of the inductor respectively; The other end of the inductor is configured to be connected to a welding device; The anode of the first diode is connected to the full-bridge circuit and the cathode of the battery pack respectively.

3. The hybrid welding machine according to claim 2, characterized in that: The duty cycle of the first power switch of the BUCK circuit is between 40% and 60%; The duty cycle of the full-bridge circuit is between 40% and 60%.

4. The hybrid welding machine according to claim 2, characterized in that: The first power switch is provided with a body diode in parallel, and the conduction direction of the body diode is consistent with the conduction direction of the first diode.

5. The hybrid welding machine according to claim 4, characterized in that: The battery of the battery pack is a storage battery; The controllable switch is configured to be operably turned on when the first power switch is turned off, so that the AC-DC conversion circuit, the full-bridge circuit and the battery pack form a charging loop.

6. The hybrid welding machine according to claim 1, characterized in that: The detection circuit includes a resistor and an optical coupler, wherein the resistor is connected to the primary positive electrode of the optical coupler, and the secondary side of the optical coupler is connected to the input end of the controller; When the AC input interface is connected to an external AC power source, the signal output from the secondary side of the optocoupler to the controller changes from a high level signal to a low level signal; when the AC input interface is disconnected from the external AC power source, the signal output from the secondary side of the optocoupler to the controller changes from a low level signal to a high level signal; Alternatively, when the AC input interface is connected to an external AC power supply, the signal output by the secondary side of the optocoupler to the controller changes from a low level signal to a high level signal; when the AC input interface is disconnected from the external AC power supply, the signal output by the secondary side of the optocoupler to the controller changes from a high level signal to a low level signal.

7. The hybrid welding machine according to claim 6, characterized in that: The controller is an MCU; Alternatively, the controller is configured with a comparator, one of the non-inverting input terminal and the inverting input terminal of the comparator is connected to the secondary voltage of the optocoupler, and the other is connected to a reference voltage, and the output terminal of the comparator is connected to the enable terminal of the controllable switch.

8. The hybrid welding machine according to claim 7, characterized in that: When the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a high level signal to a low level signal; the non-inverting input terminal of the comparator is configured to be connected to the secondary side voltage of the optocoupler, and the inverting input terminal thereof is configured to be connected to a reference voltage; Alternatively, when the AC input interface is connected to an external AC power supply, the signal output from the secondary side of the optocoupler to the controller changes from a low-level signal to a high-level signal; the non-inverting input terminal of the comparator is configured to be connected to a reference voltage, and its inverting input terminal is configured to be connected to the secondary side voltage of the optocoupler.

9. The hybrid welding machine according to claim 1, characterized in that: The AC-DC conversion circuit includes four diodes and a capacitor; The full-bridge circuit includes four power switches, a transformer and two diodes.

10. A welding system, characterized in that: The invention comprises a welding device and a hybrid welding machine as claimed in any one of claims 1 to 9, wherein the welding device is connected to an output end of a BUCK circuit of the hybrid welding machine.

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