A topology of an ultra-high frequency AC-DC welding power supply and a control method thereof

Abstract

This invention discloses an ultra-high frequency AC / DC welding power supply topology and its control method. It addresses the problem that existing welding power supplies, limited by their topology and control strategies, cannot achieve independent and precise control of the AC and DC components. The invention includes a three-phase rectifier and filter circuit for rectifying and filtering the input three-phase AC power; a full-bridge inverter circuit for converting DC power to high-frequency AC power; primary windings of two transformers connected to the full-bridge inverter circuit; one transformer connected to a DC component module via a primary secondary rectifier circuit; and the other transformer connected to a high-frequency component module via a secondary secondary rectifier circuit. The DC component module further adjusts the rectified current to output the DC component; the high-frequency component module outputs the high-frequency component; and the DC and high-frequency component modules are connected in parallel to the welding arc output device. The beneficial effect is the achievement of independent and precise control of the AC and DC components.

Description

Technical Field

[0001] This invention relates to a welding power supply topology and control method. Background Technology

[0002] Arc welding, with its low cost, flexible operation, and wide adaptability, is widely used in the automotive, shipbuilding, aerospace, and rail transportation industries. With the increasing prevalence of lightweight materials and high-strength alloys, modern welding manufacturing places higher demands on the output characteristics of welding power sources.

[0003] 1. Special process requirements for different materials: Lightweight alloys such as aluminum and magnesium alloys easily form high-melting-point, dense oxide films on their surfaces during welding (e.g., Al2O3 has a melting point of 2050℃). These oxide films must be effectively broken up using the cathode breaking action of ultra-high frequency alternating current (typically >50kHz) to achieve a stable molten pool and high-quality weld. Existing welding power supplies are limited by device switching frequencies and topologies, with output frequencies generally below 20kHz, making it difficult to meet the precision welding requirements of such materials. Stainless steel, special alloys, and other materials are sensitive to heat input, requiring precisely controlled DC pulse waveforms or AC waveforms to regulate weld penetration and weld formation, avoiding overheating that could lead to intergranular corrosion or a decline in mechanical properties. Existing power supply waveform control capabilities are limited, making it difficult to achieve refined heat input management.

[0004] 2. Technical Bottlenecks of Existing Welding Power Supply Topologies; Currently, the mainstream welding power supplies in the industry mainly adopt the following two topologies, but both have inherent limitations: 1. Single Inverter Rectifier Topology: A single inverter converts the power frequency AC to high frequency AC, which is then stepped down by a transformer and rectified twice before output. This structure can only generate a single-characteristic current. To achieve AC / DC switching, complex mechanical commutation switches or relays are required, resulting in slow response speed (milliseconds) and problems such as contact erosion and short lifespan, making it impossible to achieve fast mode switching. 2. Dual Inverter Parallel Topology: Although some high-end power supplies use two inverter units in parallel, the two outputs are usually hard-parallel, lacking independent secondary modulation capabilities. This leads to mutual coupling of AC and DC components, making independent and precise control impossible, making it difficult to achieve stable output of ultra-high frequency square waves (above 100kHz), resulting in poor dynamic response characteristics and severe waveform distortion.

[0005] 3. Limited process adaptability; limited functionality of single equipment; difficulty in multi-mode coordination: When welding complex workpieces (such as dissimilar metal joints and plates with varying thicknesses), it is often necessary to switch output modes at different welding stages; existing welding solutions rely on equipment replacement or manual parameter adjustment, making it impossible to achieve seamless online switching during the welding process, which seriously affects production efficiency and quality consistency. Frequency and power contradiction: Although increasing the switching frequency can improve waveform quality, silicon-based devices (IGBTs) have high switching losses, a sharp drop in efficiency, and difficulty in heat dissipation, making it difficult to achieve high power output at frequencies above 10kHz, forming a technical bottleneck.

[0006] 4. Demands and Challenges of High-End Precision Manufacturing; In fields such as aerospace, new energy vehicle battery trays, and electronic packaging, the requirements for weld quality, heat-affected zone control, and welding efficiency are becoming increasingly stringent; Existing welding power supplies, due to their fixed output modes, narrow frequency range, and low degree of control freedom, struggle to achieve the following objectives: Precise control of the UHF (Ultra-High Frequency) band: requiring output of a wide frequency current range of 100Hz to 100kHz+; Independent adjustment of AC and DC components: requiring separate control of the amplitude, frequency, and duty cycle of the DC base current and the AC pulse component; Rapid dynamic response: requiring response to arc load changes within microseconds, suppressing spatter, and stabilizing the arc.

[0007] In summary, existing welding power supplies are limited by their topology and control strategies, resulting in generally limited output waveform capabilities. They struggle to integrate four significantly different output modes—ultra-high frequency AC, ultra-high frequency DC, standard AC, and standard DC—on a single platform, and they are unable to achieve independent and precise control of AC and DC components. This fundamental technical bottleneck severely restricts the integrated and intelligent development of welding equipment in the field of high-end precision welding. Summary of the Invention

[0008] The purpose of this invention is to solve the problem that existing welding power supplies are limited by topology and control strategy, making it impossible to achieve independent and precise control of AC and DC components. This invention proposes an ultra-high frequency AC / DC welding power supply topology and its control method.

[0009] The ultra-high frequency AC / DC welding power supply topology of the present invention includes a three-phase rectifier and filter circuit, a full-bridge inverter circuit, a dual transformer unit, a first secondary rectifier circuit, a second secondary rectifier circuit, a DC component module, and a high-frequency component module.

[0010] The three-phase rectifier and filter circuit is used to rectify and filter the input three-phase AC power and output DC power.

[0011] The full-bridge inverter circuit is used to convert the DC power output from the three-phase rectifier and filter circuit into high-frequency AC power.

[0012] The dual transformer unit comprises two transformers. The primary input terminals of the two transformers are connected in parallel and then connected to the high-frequency AC output terminal of the full-bridge inverter circuit. The secondary output terminal of one transformer is connected to the input terminal of the DC component module through a first secondary rectifier circuit. The secondary output terminal of the other transformer is connected to the input terminal of the high-frequency component module through a second secondary rectifier circuit.

[0013] The DC component module is a Buck topology structure, used to readjust the rectified current to output a DC component.

[0014] The high-frequency component module is a full-bridge inverter topology structure used to output high-frequency components;

[0015] The output terminal of the DC component module is connected in parallel with the output terminal of the high-frequency component module and then connected to the welding arc output device.

[0016] Furthermore, the full-bridge inverter circuit includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4;

[0017] The gate of the first switch Q1 is used to input the first control signal; the source of the first switch Q1 is connected to the source of the third switch Q3, and the source of the first switch Q1 is the positive DC input terminal of the full-bridge inverter circuit 2.

[0018] The gate of the second switch Q2 is used to input the second control signal; the drain of the second switch Q2 is connected to the drain of the fourth switch Q4, and the drain of the second switch Q2 is the DC negative input terminal of the full-bridge inverter circuit; the drain of the first switch Q1 is connected to the source of the second switch Q2, and the drain of the first switch Q1 is an AC output terminal of the full-bridge inverter circuit.

[0019] The gate of the third switch Q3 is used to input the third control signal; the gate of the fourth switch Q4 is used to input the fourth control signal; wherein, the drain of the third switch Q3 is connected to the source of the fourth switch Q4, and the drain of the third switch Q3 is the other AC output terminal of the full-bridge inverter circuit.

[0020] Furthermore, the second secondary rectifier circuit includes diode D3, diode D4, and a second inductor L2;

[0021] The anode of diode D3 is connected to one end of the secondary coil of the transformer in the dual transformer unit that modulates the high-frequency component; the cathode of diode D3 is connected to the cathode of diode D4 and one end of the second inductor L2; the other end of the second inductor L2 is an output terminal of the second secondary rectifier circuit.

[0022] The anode of diode D4 is connected to the other end of the secondary coil of the transformer in the dual transformer unit that modulates the high-frequency component.

[0023] In the dual transformer unit, the common terminal of the secondary coil of the transformer that modulates the high-frequency component is the other output terminal of the second secondary rectifier circuit.

[0024] Furthermore, it also includes the sixth switch Q6;

[0025] The gate of the sixth switch Q6 is used to input the sixth control signal;

[0026] The source of the sixth switch Q6 is connected to one of the output terminals of the second secondary rectifier circuit, and the source of the sixth switch Q6 is used to connect to one of the input terminals of the high-frequency component module.

[0027] The drain of the sixth switch Q6 is connected to another output terminal of the second secondary rectifier circuit, and the drain of the sixth switch Q6 is used to connect to another input terminal of the high-frequency component module.

[0028] Furthermore, the DC component module includes a fifth switch Q5, a first inductor L1, and a diode D5;

[0029] The gate of the fifth switch Q5 is used to input the fifth control signal; the source of the fifth switch Q5 is the positive input terminal of the DC component module; the drain of the fifth switch Q5 is connected to the cathode of the diode D5 and one end of the first inductor L1, respectively.

[0030] The other end of the first inductor L1 is the positive output terminal of the DC component module;

[0031] The anode of diode D5 is the negative input terminal of the DC component module, and the anode of diode D5 is also the negative output terminal of the DC component module.

[0032] Furthermore, the high-frequency component module includes a seventh switch Q7, an eighth switch Q8, a ninth switch Q9, and a tenth switch Q10;

[0033] The gate of the seventh switch Q7 is used to input the seventh control signal; the gate of the eighth switch Q8 is used to input the eighth control signal; the gate of the ninth switch Q9 is used to input the ninth control signal; and the gate of the tenth switch Q10 is used to input the tenth control signal.

[0034] The source of the seventh switch Q7 is connected to the source of the ninth switch Q9, and the source of the seventh switch Q7 is an input terminal of the high-frequency component module.

[0035] The drain of the eighth switch Q8 is connected to the drain of the tenth switch Q10, and the drain of the eighth switch Q8 is another input terminal of the high-frequency component module.

[0036] The drain of the seventh switch Q7 is connected to the source of the eighth switch Q8, and the drain of the seventh switch Q7 serves as an output terminal of the high-frequency component module.

[0037] The drain of the ninth switch Q9 is connected to the source of the tenth switch Q10, and the drain of the ninth switch Q9 serves as another output terminal of the high-frequency component module.

[0038] Furthermore, it also includes digital controllers;

[0039] The digital controller is used to output a first control signal, a second control signal, a third control signal, a fourth control signal, a fifth control signal, a sixth control signal, a seventh control signal, an eighth control signal, a ninth control signal, and a tenth control signal.

[0040] Furthermore, the first switch Q1 to the tenth switch Q10 are all silicon carbide field-effect transistors.

[0041] A control method for an ultra-high frequency AC / DC welding power supply topology controls the first current by adjusting the duty cycle of the first switch Q1 to the fourth switch Q4. Second current ;

[0042] By adjusting the duty cycle of the fifth switch Q5, the DC component module is controlled to supply the first current. Perform secondary modulation to output DC component ;

[0043] By controlling the on / off state of the sixth switch Q6 to the tenth switch Q10, the high-frequency component output of the high-frequency component module is adjusted. According to the set welding operation mode, the DC component is... and the high-frequency components Superimposed, output welding current ; Output welding current The power supply current for the welding arc output device is supplied, thereby enabling the switching between four working modes: standard DC, standard AC, ultra-high frequency DC, or ultra-high frequency AC.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] Existing welding power supply pulse frequencies are generally below 20kHz. This invention, through an ultra-high frequency AC / DC welding topology and control method, enables it to output pulse currents up to 100Hz. A single welding power supply can meet the high-quality welding needs of various materials such as aluminum alloys, magnesium alloys requiring ultra-high frequency AC oxide film removal, stainless steel, carbon steel, and special alloys, eliminating the need to purchase multiple dedicated devices for different processes. Through the flexible combination and rapid switching of four modes, independent and precise control of AC and DC components is achieved, thereby enabling optimal process parameter matching for different plate thicknesses, joint types, and welding positions (horizontal, horizontal, vertical, and overhead). This ensures aesthetically pleasing weld formation and reduces internal defects such as porosity and lack of fusion. Attached Figure Description

[0046] Figure 1 The circuit diagram shows the topology of an ultra-high frequency AC / DC welding power supply as described in Specific Implementation Method 1.

[0047] Figure 2 This is a schematic diagram of a specific UHF DC and UHF AC output control method in Implementation Method 1. Detailed Implementation

[0048] Specific Implementation Method 1: Combination Figures 1 to 2 This embodiment describes an ultra-high frequency AC / DC welding power supply topology that includes a three-phase rectifier filter circuit 1, a full-bridge inverter circuit 2, a dual transformer unit 3, a first secondary rectifier circuit 4, a second secondary rectifier circuit 5, a DC component module 6, and a high-frequency component module 7.

[0049] The three-phase rectifier and filter circuit 1 is used to rectify and filter the input three-phase AC power and output DC power.

[0050] The full-bridge inverter circuit 2 is used to convert the DC power output from the three-phase rectifier filter circuit 1 into high-frequency AC power.

[0051] The dual transformer unit 3 includes two transformers. The primary input terminals of the two transformers are connected in parallel and then connected to the high-frequency AC output terminal of the full-bridge inverter circuit 2. The secondary output terminal of one transformer is connected to the input terminal of the DC component module 6 through the first secondary rectifier circuit 4. The secondary output terminal of the other transformer is connected to the input terminal of the high-frequency component module 7 through the second secondary rectifier circuit 5.

[0052] The DC component module 6 is a Buck topology structure, used to readjust the rectified current to output a DC component.

[0053] The high-frequency component module 7 is a full-bridge inverter topology structure used to output high-frequency components;

[0054] The output terminal of the DC component module 6 is connected in parallel with the output terminal of the high-frequency component module 7 and then connected to the welding arc output device 8.

[0055] In this embodiment, a high-frequency AC / DC composite welding power supply topology is provided. A three-phase rectifier and filter circuit 1 is connected to a full-bridge inverter circuit 2, converting DC power into high-frequency AC power. The full-bridge inverter circuit 2 is connected to a transformer 3, converting high-voltage, low-current AC power into low-voltage, high-current AC power. Secondary rectifier circuits 4 and 5 are connected to the two output ports of transformer 3, converting AC current into DC power. Secondary rectifier circuit 4 is then connected to a DC component module 6, outputting the DC component of the welding current. Secondary rectifier circuit 5 is connected to a high-frequency component module 7, outputting the high-frequency component of the welding current. The DC and high-frequency components are then superimposed and output through a welding arc output device 8. In this topology, the DC component module 6 and the high-frequency component module 7 are independently controllable and do not affect each other, each generating a controllable DC and high-frequency component. The DC and high-frequency components are decoupled by the dual transformer unit 3. Combined with the DC component module 4 of the Buck topology and the high-frequency component module 5 of the full-bridge inverter topology, independent and precise control of the AC and DC components is achieved. Figure 1 As shown, one transformer in the dual transformer unit 3 is transformer T1, and the other transformer is transformer T2. The primary winding input terminals of transformers T1 and T2 are connected in parallel and then connected to the high-frequency AC output terminal of the full-bridge inverter circuit 2. The secondary output terminal of transformer T1 is connected to the input terminal of the DC component module 6 through the first secondary rectifier circuit 4 (including diodes D1 and D2). The secondary output terminal of the other transformer is connected to the input terminal of the high-frequency component module 7 through the second secondary rectifier circuit 5. This topology allows a single power supply to output four modes (standard DC, standard AC, ultra-high frequency DC, and ultra-high frequency AC), breaking through the bottleneck of existing power supply output frequencies below 20kHz. It can output ultra-high frequency currents above 100kHz, meeting the cathode crushing requirements of lightweight alloys such as aluminum alloys and magnesium alloys, as well as the fine heat input management of materials such as stainless steel.

[0056] The method of using the aforementioned ultra-high frequency AC / DC welding power supply topology includes the following steps:

[0057] Step 1: Before welding, grind and clean the workpiece to be welded, and fix it on the tooling fixture;

[0058] Step 2: Through the human-machine interface of the welding power supply, select the required working mode (ultra-high frequency AC, ultra-high frequency DC, standard AC or standard DC), and set key process parameters such as target output peak current, base current, peak time, and base time.

[0059] Step 3: The main control system of the welding power supply automatically generates and loads the corresponding power switch modulation strategy according to the set working mode and parameters to configure the output characteristics of the power supply;

[0060] Step 4: Start the welding process. The welding power source starts the arc at high frequency. After the arc stabilizes, switch to the preset main welding program.

[0061] Step 5: During the welding process, the output current signal of the welding power source is collected in real time and compared with the expected value set in Step 2 to verify the reliability of the output.

[0062] Specific Implementation Method 2: This implementation method further defines the topology of an ultra-high frequency AC / DC welding power supply described in Specific Implementation Method 1. In this implementation method, the full-bridge inverter circuit 2 includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4.

[0063] The gate of the first switch Q1 is used to input the first control signal; the source of the first switch Q1 is connected to the source of the third switch Q3, and the source of the first switch Q1 is the positive DC input terminal of the full-bridge inverter circuit 2.

[0064] The gate of the second switch Q2 is used to input the second control signal; the drain of the second switch Q2 is connected to the drain of the fourth switch Q4, and the drain of the second switch Q2 is the DC negative input terminal of the full-bridge inverter circuit 2; the drain of the first switch Q1 is connected to the source of the second switch Q2, and the drain of the first switch Q1 is an AC output terminal of the full-bridge inverter circuit 2.

[0065] The gate of the third switch Q3 is used to input the third control signal; the gate of the fourth switch Q4 is used to input the fourth control signal; wherein, the drain of the third switch Q3 is connected to the source of the fourth switch Q4, and the drain of the third switch Q3 is another AC output terminal of the full-bridge inverter circuit 2.

[0066] In this embodiment, the full-bridge inverter circuit uses four independently controlled switching transistors, which can efficiently convert DC power into high-frequency AC power. By adjusting the duty cycle, it can precisely control the energy transmission on the primary side of the transformer, providing a stable and controllable power source for the subsequent independent modulation of DC and high-frequency components, while also supporting fast dynamic response.

[0067] Specific Implementation Method 3: This implementation method further defines the topology of an ultra-high frequency AC / DC welding power supply described in Specific Implementation Method 2. In this implementation method, the second secondary rectifier circuit 5 includes diode D3, diode D4, and second inductor L2.

[0068] The anode of diode D3 is connected to one end of the secondary coil of the transformer in the dual transformer unit 3 that modulates the high-frequency component; the cathode of diode D3 is connected to the cathode of diode D4 and one end of the second inductor L2; the other end of the second inductor L2 is an output terminal of the second secondary rectifier circuit 5.

[0069] The anode of diode D4 is connected to the other end of the secondary coil of the transformer in the dual transformer unit 3, which modulates the high-frequency component.

[0070] The common terminal of the secondary coil of the transformer in the dual transformer unit 3, which modulates the high-frequency component, is another output terminal of the second secondary rectifier circuit 5.

[0071] In this embodiment, the transformer that modulates the high-frequency component is another transformer in the dual transformer unit 3, namely transformer T2; the second secondary rectifier circuit 5 adopts a dual diode plus inductor structure, which rectifies the high-frequency component branch and stores and filters energy through the second inductor L2 to ensure that the current input to the high-frequency component module is smooth and without fluctuation; this provides a stable DC bus for the output ultra-high frequency square wave, avoids the distortion of the input current during high-frequency modulation, and ensures the waveform quality.

[0072] Specific Implementation Method Four: This implementation method further defines the topology of an ultra-high frequency AC / DC welding power supply described in Specific Implementation Method Three. In this implementation method, a sixth switching transistor Q6 is also included.

[0073] The gate of the sixth switch Q6 is used to input the sixth control signal;

[0074] The source of the sixth switch Q6 is connected to one of the output terminals of the second secondary rectifier circuit 5, and the source of the sixth switch Q6 is used to connect to one of the input terminals of the high-frequency component module 7.

[0075] The drain of the sixth switch Q6 is connected to another output terminal of the second secondary rectifier circuit 5, and the drain of the sixth switch Q6 is used to connect to another input terminal of the high-frequency component module 7.

[0076] In this embodiment, the sixth switch Q6 is used to prevent voltage surges, and the second inductor L2 must have a freewheeling path. Therefore, the sixth switch Q6 is added after the second inductor L2. Under certain circumstances, the sixth switch Q6 is turned on to maintain the freewheeling current of the second inductor L2 to prevent circuit damage.

[0077] Specific Implementation Method 5: This implementation method further defines the topology of an ultra-high frequency AC / DC welding power supply described in Specific Implementation Method 4. In this implementation method, the DC component module 6 includes a fifth switch Q5, a first inductor L1, and a diode D5.

[0078] The gate of the fifth switch Q5 is used to input the fifth control signal; the source of the fifth switch Q5 is the positive input terminal of the DC component module 6; the drain of the fifth switch Q5 is connected to the cathode of the diode D5 and one end of the first inductor L1, respectively.

[0079] The other end of the first inductor L1 is the positive output terminal of the DC component module 6;

[0080] The anode of diode D5 is the negative input terminal of DC component module 6, and the anode of diode D5 is also the negative output terminal of DC component module 6.

[0081] In this embodiment, the DC component module 6 adopts a Buck topology. By adjusting the duty cycle of the fifth switch Q5, the first current can be controlled. Secondary modulation (first current) This is the output current after connecting the cathodes of diodes D1 and D2, precisely outputting the required DC component. This structure is simple and reliable, achieving independent, high-precision control of the welding current base value (DC component), unaffected by high-frequency components.

[0082] Specific Implementation Method Six: This implementation method further defines the ultra-high frequency AC / DC welding power supply topology described in Specific Implementation Method Five. In this implementation method, the high frequency component module 7 includes a seventh switch Q7, an eighth switch Q8, a ninth switch Q9, and a tenth switch Q10.

[0083] The gate of the seventh switch Q7 is used to input the seventh control signal; the gate of the eighth switch Q8 is used to input the eighth control signal; the gate of the ninth switch Q9 is used to input the ninth control signal; and the gate of the tenth switch Q10 is used to input the tenth control signal.

[0084] The source of the seventh switch Q7 is connected to the source of the ninth switch Q9, and the source of the seventh switch Q7 is an input terminal of the high-frequency component module 7.

[0085] The drain of the eighth switch Q8 is connected to the drain of the tenth switch Q10, and the drain of the eighth switch Q8 is another input terminal of the high-frequency component module 7.

[0086] The drain of the seventh switch Q7 is connected to the source of the eighth switch Q8, and the drain of the seventh switch Q7 serves as an output terminal of the high-frequency component module 7.

[0087] The drain of the ninth switch Q9 is connected to the source of the tenth switch Q10, and the drain of the ninth switch Q9 serves as another output terminal of the high-frequency component module 7.

[0088] In this embodiment, the high-frequency component module 7 adopts a full-bridge inverter topology (seventh to tenth switches), which can flexibly control the amplitude, frequency, and duty cycle of the output high-frequency components. Through the rapid switching of the seventh to tenth switches, high-frequency components up to 100kHz can be generated. After being superimposed with the DC component, complex waveform outputs are achieved, meeting the process requirements of precision welding of special alloys.

[0089] Specific Implementation Method Seven: This implementation method further defines the topology of an ultra-high frequency AC / DC welding power supply described in Specific Implementation Method Six. In this implementation method, the first switch Q1 to the tenth switch Q10 are all silicon carbide field-effect transistors.

[0090] In this embodiment, all switching transistors are silicon carbide field-effect transistors (SiC MOSFETs). By utilizing their high switching frequency (up to hundreds of kHz), low switching loss and high temperature stability, the problem of sharp efficiency drop and heat dissipation difficulties of existing silicon-based devices (IGBTs) when operating at frequencies above 10 kHz is solved, enabling the power supply to maintain high efficiency and high power output in the ultra-high frequency range.

[0091] Specific Implementation Method 8: This implementation method further defines the ultra-high frequency AC / DC welding power supply topology described in Specific Implementation Method 6 or 7. In this implementation method, a digital controller is also included.

[0092] The digital controller is used to output a first control signal, a second control signal, a third control signal, a fourth control signal, a fifth control signal, a sixth control signal, a seventh control signal, an eighth control signal, a ninth control signal, and a tenth control signal.

[0093] In this embodiment, the independent components are modulated by a high-speed digital controller, and the final output welding current ranges from standard to ultra-high frequency bands.

[0094] In this embodiment, ten control signals are uniformly generated by a digital controller, enabling digital and coordinated control of the full-bridge inverter, DC component module 6, and high-frequency component module 7. Compared to analog control, digital control strategies are more flexible, allowing for rapid switching of operating modes in microseconds, dynamic response to changes in arc load, suppression of spatter, and easier optimization of welding process algorithms through software upgrades.

[0095] Specific Implementation Method Nine: A control method based on the ultra-high frequency AC / DC welding power supply topology described in Specific Implementation Method Six. In this embodiment, the first current is controlled by adjusting the duty cycle of the first switch Q1 to the fourth switch Q4. Second current ;

[0096] By adjusting the duty cycle of the fifth switch Q5, the DC component module 6 is controlled to supply the first current. Perform secondary modulation to output DC component ;

[0097] By controlling the on / off state of the sixth switch Q6 to the tenth switch Q10, the high-frequency component output of the high-frequency component module 7 is adjusted. According to the set welding operation mode, the DC component is... and the high-frequency components Superimposed, output welding current ; Output welding current This provides the power supply current for the welding arc output device 8, thereby enabling the switching between four working modes: standard DC, standard AC, ultra-high frequency DC, or ultra-high frequency AC.

[0098] In this embodiment, the current The current flowing through the second inductor L2; The DC component passing through the first inductor L1; The high-frequency component output by high-frequency component module 7; output welding current. The power supply current for the welding arc output device 8 is also the output current of an ultra-high frequency AC / DC welding power supply topology; complex waveform output is achieved by controlling ten switching transistors. First, the current... and current The magnitude is achieved by adjusting the duty cycles of the first switch Q1 to the fourth switch Q4. Subsequently, by adjusting the duty cycle of the fifth switch Q5, the DC component module 6... Secondary modulation is performed to convert it into a DC component. This allows for the output of constant current or low-frequency square wave current. Due to the DC component... The magnitude is controlled by DC component module 6. The amplitude does not affect the DC component of the welding current, so the first switch Q1 to the fourth switch Q4 are mainly used for control. The magnitude of the current thus changes the high-frequency components. Regarding the amplitude, it is worth noting that, in order to achieve a standard ultra-high frequency pulse square wave output, the secondary rectifier circuit 5, after rectification, also needs to use an inductor for energy storage and filtering to ensure that the input current does not fluctuate when the high-frequency component module 7 is working. Since the inductor must have a freewheeling path, it is necessary to turn on the sixth switch Q6 and turn off the seventh to tenth switches Q10 when necessary. This achieves independent control of the DC component module 6 and the high-frequency component module 7 and provides a freewheeling path for the second inductor L2. This is achieved by coordinating the DC component... The magnitude of the value is adjusted to control the conduction and cutoff of the seventh switch Q7 to the tenth switch Q10, thereby achieving the output of high-frequency current.

[0099] The welding operation modes can be divided into four types: DC, AC, UHF DC, and UHF AC. The DC component module 6 can adjust the base value of the welding current output; the high-frequency component module 7 is used to adjust the high-frequency component. By changing the duty cycle of the switching transistors in the full-bridge inverter circuit 2, the input current of the high-frequency component module 7 is changed, which also changes the peak value of the high-frequency component in the welding current. If the output is constant DC, the high-frequency component module 7 does not work, and the output current is adjusted by the full-bridge inverter circuit 2 and the DC component module 6; if the output is pure AC, the DC component module 6 does not work, and the output current is adjusted by the full-bridge inverter circuit 2 and the high-frequency component module 7; if the output is UHF DC, a high-frequency current is generated through a specific control strategy of the high-frequency component module 7, and superimposed on the DC component output of the DC component module 6 to achieve the high-frequency current output; if the output is UHF AC, a high-frequency AC current is generated through a specific control strategy of the high-frequency component module 7, and superimposed on the DC component output of the DC component module 6 to achieve the high-frequency AC current output.

[0100] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A topology for an ultra-high frequency AC / DC welding power supply, characterized in that, It includes a three-phase rectifier filter circuit (1), a full-bridge inverter circuit (2), a dual transformer unit (3), a first secondary rectifier circuit (4), a second secondary rectifier circuit (5), a DC component module (6), and a high-frequency component module (7). The three-phase rectifier and filter circuit (1) is used to rectify and filter the input three-phase AC power and output DC power. The full-bridge inverter circuit (2) is used to convert the DC power output from the three-phase rectifier filter circuit (1) into high-frequency AC power. The dual transformer unit (3) includes two transformers. The primary input terminals of the two transformers are connected in parallel and then connected to the high-frequency AC output terminal of the full-bridge inverter circuit (2). The secondary output terminal of one transformer is connected to the input terminal of the DC component module (6) through the first secondary rectifier circuit (4). The secondary output terminal of the other transformer is connected to the input terminal of the high-frequency component module (7) through the second secondary rectifier circuit (5). The DC component module (6) is a Buck topology structure, used to readjust the rectified current to output a DC component; The high-frequency component module (7) is a full-bridge inverter topology structure used to output high-frequency components; The output terminal of the DC component module (6) is connected in parallel with the output terminal of the high-frequency component module (7) and then connected to the welding arc output device (8).

2. The ultra-high frequency AC / DC welding power supply topology according to claim 1, characterized in that, The full-bridge inverter circuit (2) includes a first switch Q1, a second switch Q2, a third switch Q3 and a fourth switch Q4; The gate of the first switch Q1 is used to input the first control signal; the source of the first switch Q1 is connected to the source of the third switch Q3, and the source of the first switch Q1 is the DC positive input terminal of the full-bridge inverter circuit (2). The gate of the second switch Q2 is used to input the second control signal; the drain of the second switch Q2 is connected to the drain of the fourth switch Q4, and the drain of the second switch Q2 is the DC negative input terminal of the full-bridge inverter circuit (2); the drain of the first switch Q1 is connected to the source of the second switch Q2, and the drain of the first switch Q1 is an AC output terminal of the full-bridge inverter circuit (2); The gate of the third switch Q3 is used to input the third control signal; the gate of the fourth switch Q4 is used to input the fourth control signal; wherein, the drain of the third switch Q3 is connected to the source of the fourth switch Q4, and the drain of the third switch Q3 is the other AC output terminal of the full-bridge inverter circuit (2).

3. The ultra-high frequency AC / DC welding power supply topology according to claim 2, characterized in that, The second secondary rectifier circuit (5) includes diode D3, diode D4, and second inductor L2; The anode of diode D3 is connected to one end of the secondary coil of the transformer in the dual transformer unit (3) that modulates the high-frequency component; the cathode of diode D3 is connected to the cathode of diode D4 and one end of the second inductor L2; the other end of the second inductor L2 is an output terminal of the second secondary rectifier circuit (5). The anode of the diode D4 is connected to the other end of the secondary coil of the transformer in the dual transformer unit (3) that modulates the high-frequency components. The common terminal of the secondary coil of the transformer in the dual transformer unit (3) that modulates the high-frequency component is the other output terminal of the second secondary rectifier circuit (5).

4. The ultra-high frequency AC / DC welding power supply topology according to claim 3, characterized in that, It also includes the sixth switching transistor Q6; The gate of the sixth switch Q6 is used to input the sixth control signal; The source of the sixth switch Q6 is connected to one of the output terminals of the second secondary rectifier circuit (5), and the source of the sixth switch Q6 is used to connect to one of the input terminals of the high-frequency component module (7). The drain of the sixth switch Q6 is connected to another output terminal of the second secondary rectifier circuit (5), and the drain of the sixth switch Q6 is used to connect to another input terminal of the high-frequency component module (7).

5. The ultra-high frequency AC / DC welding power supply topology according to claim 4, characterized in that, The DC component module (6) includes a fifth switch Q5, a first inductor L1, and a diode D5; The gate of the fifth switch Q5 is used to input the fifth control signal; the source of the fifth switch Q5 is the positive input terminal of the DC component module (6); the drain of the fifth switch Q5 is connected to the cathode of the diode D5 and one end of the first inductor L1 respectively. The other end of the first inductor L1 is the positive output terminal of the DC component module (6); The anode of diode D5 is the negative input terminal of the DC component module (6), and the anode of diode D5 is the negative output terminal of the DC component module (6).

6. The ultra-high frequency AC / DC welding power supply topology according to claim 5, characterized in that, The high-frequency component module (7) includes a seventh switch Q7, an eighth switch Q8, a ninth switch Q9 and a tenth switch Q10; The gate of the seventh switch Q7 is used to input the seventh control signal; the gate of the eighth switch Q8 is used to input the eighth control signal; the gate of the ninth switch Q9 is used to input the ninth control signal; and the gate of the tenth switch Q10 is used to input the tenth control signal. The source of the seventh switch Q7 is connected to the source of the ninth switch Q9, and the source of the seventh switch Q7 is an input terminal of the high-frequency component module (7). The drain of the eighth switch Q8 is connected to the drain of the tenth switch Q10, and the drain of the eighth switch Q8 is another input terminal of the high-frequency component module (7). The drain of the seventh switch Q7 is connected to the source of the eighth switch Q8, and the drain of the seventh switch Q7 serves as an output terminal of the high-frequency component module (7). The drain of the ninth switch Q9 is connected to the source of the tenth switch Q10, and the drain of the ninth switch Q9 serves as another output terminal of the high-frequency component module (7).

7. The ultra-high frequency AC / DC welding power supply topology according to claim 6, characterized in that, It also includes digital controllers; The digital controller is used to output a first control signal, a second control signal, a third control signal, a fourth control signal, a fifth control signal, a sixth control signal, a seventh control signal, an eighth control signal, a ninth control signal, and a tenth control signal.

8. The ultra-high frequency AC / DC welding power supply topology according to claim 6 or 7, characterized in that, The first switch Q1 to the tenth switch Q10 are all silicon carbide field-effect transistors.

9. A control method for an ultra-high frequency AC / DC welding power supply topology as described in claim 6, characterized in that, The first current is controlled by adjusting the duty cycles of the first switch Q1 to the fourth switch Q4. Second current ; By adjusting the duty cycle of the fifth switch Q5, the DC component module (6) is controlled to control the first current. Perform secondary modulation to output DC component ; By controlling the on and off states of the sixth switch Q6 to the tenth switch Q10, the high-frequency component output of the high-frequency component module (7) is adjusted. According to the set welding operation mode, the DC component is... and the high-frequency components Superimposed, output welding current ; Output welding current The power supply current for the welding arc output device (8) is provided; thereby enabling the switching of four working modes: standard DC, standard AC, ultra-high frequency DC or ultra-high frequency AC.

Images