A welding current balance optimization module and method

Abstract

The present application belongs to the technical field of welding power supply, in order to solve the problem of uneven current of multi-module parallel in the prior art, a welding current balance optimization module and method are disclosed, the present application sets current sampling units in each IGBT inverter branch to collect the output current in real time, and the central control processing unit synchronously samples and calculates the current imbalance degree of each branch; wherein, when the imbalance degree of a certain branch is out of limit, the central control processing unit accurately calculates the required gate drive voltage according to the real-time current of each branch, and generates a voltage adjustment signal to control the corresponding gate drive unit, so as to dynamically adjust the gate drive voltage amplitude of the IGBT full bridge of each branch, so that the current imbalance degree of each branch is reduced to within the threshold value; in this way, the present application realizes active balance adjustment of the output current of multi-IGBT inverter branch, effectively solving the problem of uneven current distribution caused by the difference of device parameters.

Description

Technical Field

[0001] This invention belongs to the field of welding power source technology, specifically relating to a welding current balance optimization module and method, applicable to continuous uninterrupted welding scenarios of various materials such as titanium alloy, stainless steel, and aluminum alloy. Background Technology

[0002] In the welding process of ultra-long welds (such as kilometer or ten thousand meters), the welding power supply needs to work continuously for hundreds of hours. Traditional high-power welding usually uses multiple power modules to operate in parallel. However, due to differences in device parameters, uneven current distribution between modules is prone to occur, leading to overheating or output distortion of some modules, arc instability, and defects such as undercut and humps.

[0003] The aforementioned technical challenges have caused serious industry problems in practical applications. In key areas such as shipbuilding, pressure vessels, nuclear power pipelines, and long-distance oil and gas pipelines, the welding quality of ultra-long welds directly affects the safety and service life of the entire structure. Taking long-distance oil and gas pipelines as an example, a single pipeline often spans thousands of kilometers. Any defect in a weld caused by unstable welding power output can become a potential leak during pipeline operation, thereby causing major safety accidents. According to statistics, in the manufacturing of large structural components and pipeline projects, rework costs due to welding defects can account for more than 30% of the total manufacturing cost, and weld quality problems are one of the main causes of failure of in-service equipment.

[0004] From the perspective of the industrial chain, the reliability of welding power sources has become a bottleneck restricting the development of the high-end equipment manufacturing industry. On the one hand, downstream users (such as shipbuilding companies, pressure vessel manufacturers, and pipeline construction units) have to adopt inefficient processes such as segmented welding and multiple flaw detection to ensure welding quality, which prolongs the production cycle and increases manufacturing costs. On the other hand, upstream welding power source manufacturers are limited by technological bottlenecks and find it difficult to meet the demand of high-end users for long weld seam continuous welding equipment, resulting in the continued reliance on imports for key components. This technological shortcoming not only affects the overall efficiency of the industrial chain, but also creates technological dependence risks in strategic fields such as aerospace, nuclear energy, and oil and gas transportation.

[0005] Therefore, there is an urgent need to provide a current balance optimization technology that can achieve continuous and stable welding of ultra-long welds, in order to solve the problems of uneven current distribution in parallel multi-modules and low reliability during long-term operation in existing technologies, thereby improving the level of high-end equipment manufacturing, perfecting the independent industrial chain, and ensuring the security of national energy infrastructure. Summary of the Invention

[0006] The purpose of this invention is to provide a welding current balance optimization module and method to solve the problems of uneven current distribution in parallel multi-module operation and low reliability during long-term operation in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, a welding current balance optimization module is provided, including: The central control processing unit and at least two parallel IGBT inverter branches, wherein each IGBT inverter branch includes a current sampling unit, a gate drive unit and an IGBT full bridge; The current sampling unit in each IGBT inverter branch is used to collect the output current on the IGBT full bridge in its corresponding IGBT inverter branch and generate a detection signal to be output to the central control processing unit. The central control processing unit is used to synchronously sample the detection signals output by each current sampling unit to obtain the real-time current of each IGBT inverter branch, and calculate the current imbalance of each IGBT inverter branch based on each real-time current. When the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, the gate drive voltage of each IGBT inverter branch is calculated based on the real-time current of each IGBT inverter branch. The central control processing unit is also used to generate voltage regulation signals for each IGBT inverter branch according to each gate drive voltage, and transmit each voltage regulation signal to the gate drive unit in the corresponding IGBT inverter branch, so that each gate drive unit adjusts the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage regulation signal, so that after adjustment, the current imbalance of each IGBT inverter branch is less than or equal to the imbalance threshold.

[0008] Based on the above disclosure, this invention sets up current sampling units in each IGBT inverter branch to collect their respective output currents in real time. The central control processing unit synchronously samples and calculates the current imbalance of each branch. When the imbalance of a branch exceeds the limit, the central control processing unit accurately calculates the required gate drive voltage based on the real-time current of each branch and generates a voltage adjustment signal to control the corresponding gate drive unit. This dynamically adjusts the gate drive voltage amplitude of the IGBT full-bridge in each branch, thereby reducing the current imbalance of each branch to within the threshold. Thus, this invention achieves active equalization adjustment of the output current of multiple IGBT inverter branches, effectively solving the problem of uneven current distribution caused by differences in device parameters, avoiding overheating or output distortion in some modules, significantly improving arc stability, and suppressing welding defects such as undercut and humps. Therefore, this invention can ensure stable welding of ultra-long welds for hundreds of hours continuously, significantly reducing rework costs, improving production efficiency, and eliminating dependence on imported welding power supplies, thus providing reliable technical support for national energy infrastructure and high-end equipment manufacturing. Therefore, this invention is highly suitable for large-scale application and promotion.

[0009] In one possible design, the central control processing unit includes: an ADC unit, a synchronous sampling control unit, an active droop calculation unit, and a drive voltage output unit; The synchronous sampling control unit is used to trigger the ADC unit to synchronously sample the detection signals output by each current sampling unit at a fixed time in each PWM cycle of any IGBT inverter branch, so as to obtain the real-time current of each IGBT inverter branch and transmit it to the active droop calculation unit. An active droop calculation unit is used to calculate the average current based on the real-time current of each IGBT inverter branch, and to calculate the current imbalance of each IGBT inverter branch based on the average current. The active droop calculation unit is also used to calculate the gate drive voltage of each IGBT inverter branch based on the real-time current of each IGBT inverter branch when the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, and transmit it to the drive voltage output unit. The drive voltage output unit is used to generate voltage regulation signals corresponding to each IGBT inverter branch based on the gate drive voltage of each IGBT inverter branch.

[0010] In one possible design, when calculating the current imbalance of each IGBT inverter branch based on the average current, the active droop calculation unit is configured as follows: The difference between the real-time current and the average current corresponding to each IGBT inverter branch is calculated to obtain the current deviation of each IGBT inverter branch. The ratio of the absolute value of each current deviation to the average current is calculated to obtain the current imbalance degree corresponding to each IGBT inverter branch.

[0011] In one possible design, when the gate drive voltage of each IGBT inverter branch is calculated based on the real-time current corresponding to each IGBT inverter branch, the active droop calculation unit is configured as follows: Obtain the rated gate drive voltage and preset operating current of each IGBT inverter branch; The cumulative current error of each IGBT inverter branch within a preset time period is calculated, and the integral cumulative error is calculated based on the cumulative current error. The real-time current error of each IGBT inverter branch is calculated based on the preset operating current and real-time current of each IGBT inverter branch. The gate drive voltage of each IGBT inverter branch is calculated based on the real-time current error, integral cumulative error, and rated gate drive voltage of each IGBT inverter branch.

[0012] In one possible design, the active droop calculation unit is used to calculate the gate drive voltage of each IGBT inverter branch according to the following formula; ; In the formula, This represents the gate drive voltage of the i-th IGBT inverter branch. This represents the rated gate drive voltage of the i-th IGBT inverter branch. The droop coefficient is... Let be the real-time current error of the i-th IGBT inverter branch. This is the proportionality coefficient. This represents the cumulative integral error of the i-th IGBT inverter branch.

[0013] In one possible design, the gate drive unit includes: an adjustable gate drive power supply and a gate drive circuit; The input terminal of the adjustable gate drive power supply in each IGBT inverter branch is electrically connected to the central control processing unit, the output terminal of each adjustable gate drive power supply is electrically connected to the power supply input terminal of the gate drive circuit in the corresponding IGBT inverter branch, the controlled terminal of each gate drive circuit is electrically connected to the PWM output pin of the central control processing unit, and the output terminal of each gate drive circuit is electrically connected to the gate of the IGBT power device in the corresponding IGBT inverter branch. The central control processing unit is used to transmit each voltage adjustment signal to the adjustable gate drive power supply in the corresponding IGBT inverter branch, so that each adjustable gate drive power supply adjusts the output voltage of each gate drive circuit according to the received voltage adjustment signal, so as to control each gate drive circuit to adjust the gate drive voltage amplitude of its corresponding IGBT inverter branch based on the output voltage.

[0014] In one possible design, each gate drive circuit is also provided with a fault output pin, and each gate drive circuit is electrically connected to the central control processing unit through the fault output pin. Specifically, when the central control processing unit detects that the real-time current corresponding to any IGBT inverter branch is greater than the overcurrent threshold, or when the central control processing unit receives a fault signal sent by the fault output pin of any gate drive circuit, it stops the PWM output of all IGBT inverter branches and adjusts the output voltage of the adjustable gate drive power supply in each IGBT inverter branch to the minimum safe voltage.

[0015] In one possible design, the current sampling unit includes a Hall current sensor; wherein, the Hall current sensor in each IGBT inverter branch is used to collect the output current on the IGBT full bridge in its corresponding IGBT inverter branch, and convert the collected output current into an analog voltage signal as a detection signal to be output to the central control processing unit.

[0016] In one possible design, the central control processing unit is used to perform moving average or first-order low-pass filtering on each real-time current to obtain the processed current, so as to calculate the current imbalance of each IGBT inverter branch based on the processed current.

[0017] Secondly, a welding current balance optimization method is provided, wherein the method is executed based on the welding current balance optimization module of the first aspect or any possible design of the first aspect, and the method includes: The current sampling unit in each IGBT inverter branch collects the output current on the IGBT full bridge in its corresponding IGBT inverter branch and generates a detection signal to be output to the central control processing unit. The central control processing unit synchronously samples the detection signals output by each current sampling unit to obtain the real-time current of each IGBT inverter branch. Based on the real-time current, it calculates the current imbalance of each IGBT inverter branch. When the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, it calculates the gate drive voltage of each IGBT inverter branch based on the real-time current corresponding to each IGBT inverter branch. The central control processing unit generates voltage regulation signals for each IGBT inverter branch based on each gate drive voltage, and transmits each voltage regulation signal to the gate drive unit in the corresponding IGBT inverter branch, so that each gate drive unit adjusts the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage regulation signal, so that after adjustment, the current imbalance of each IGBT inverter branch is less than or equal to the imbalance threshold.

[0018] Thirdly, a welding current balance optimization device is provided. Taking the device as an electronic device as an example, it includes a memory, a processor, and a transceiver that are connected in sequence. The memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the welding current balance optimization method as described in the second aspect.

[0019] Fourthly, a storage medium is provided, on which instructions are stored, which, when executed on a computer, perform the welding current balance optimization method as described in the second aspect.

[0020] Fifthly, a computer program product containing instructions is provided, which, when executed on a computer, cause the computer to perform the welding current balance optimization method as described in the second aspect.

[0021] Beneficial effects: (1) This invention realizes the active equalization adjustment of the output current of multiple IGBT inverter branches, effectively solves the problem of uneven current distribution caused by differences in device parameters, avoids overheating or output distortion of some modules, significantly improves arc stability, and thus suppresses welding defects such as undercut and humps; therefore, this invention can ensure stable welding of ultra-long welds for hundreds of hours, greatly reduce rework costs, improve production efficiency, and get rid of dependence on imported welding power sources, thus providing reliable technical support for national energy infrastructure and high-end equipment manufacturing; therefore, this invention is very suitable for large-scale application and promotion. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the welding current balance optimization module provided in an embodiment of the present invention; Figure 2 A circuit diagram of an IGBT full-bridge provided in an embodiment of the present invention; Figure 3 A flowchart for welding current balance optimization control provided in an embodiment of the present invention; Figure 4 A flowchart illustrating the steps of the welding current balance optimization method provided in this embodiment of the invention. Detailed Implementation

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0024] It should be understood that although the terms first, second, etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit, without departing from the scope of the exemplary embodiments of the invention.

[0025] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.

[0026] Example: See Figures 1-3 As shown, the welding current balance optimization module provided in the first aspect of this embodiment may include, but is not limited to, a central control processing unit and at least two IGBT inverter branches connected in parallel (the number of IGBT inverter branches can be set according to actual use; this embodiment uses two IGBT inverter branches as an example, namely IGBT-A and IGBT-B, etc.). Figure 1 As shown in the figure), the central control processing unit may, but is not limited to, adopt a digital signal processor (DSP), and any IGBT inverter branch may, but is not limited to, include a current sampling unit, a gate drive unit, and an IGBT full bridge. Thus, in this embodiment, the output current of each branch is collected in real time by the current sampling unit in each IGBT inverter branch. Then, the central control processing unit determines whether there is current imbalance in each branch based on the real-time current of each branch. When there is current imbalance in any branch, the gate drive voltage amplitude of each branch is adjusted by the gate drive unit, so that the current of each parallel IGBT inverter branch tends to be balanced, thereby avoiding the problem of uneven current distribution caused by differences in device parameters.

[0027] Optionally, the working process of the welding current balance optimization module is as follows: Each IGBT inverter branch has a current sampling unit used to collect the output current on the IGBT full-bridge within its corresponding IGBT inverter branch and generate a detection signal to be output to the central control processing unit. In specific applications, the current sampling unit may, but is not limited to, include a Hall current sensor (i.e.,...). Figure 1The Hall current sensor is installed in the main power circuit (i.e., IGBT full bridge) of the corresponding IGBT inverter branch in a non-contact through-hole manner, and its output terminal is directly connected to the input pin of the analog-to-digital converter (ADC) of the DSP. Based on this, the Hall current sensor in each IGBT inverter branch is used to collect the output current on the IGBT full bridge in its corresponding IGBT inverter branch, and the collected output current is converted into an analog voltage signal as a detection signal, which is then output to the central control processing unit.

[0028] Optionally, the Hall current sensor mentioned above can be, but is not limited to, a magnetic balance (zero flux) Hall current sensor with a rated current of not less than 1000A and an accuracy of not less than ±0.5%. Of course, the specific selection can be set according to the actual use, and this embodiment is not limited to the example mentioned above.

[0029] Furthermore, the circuit diagram of the IGBT full-bridge can be found in [reference needed]. Figure 2 As shown, in this embodiment, the data collected is... Figure 2 The output current of the circuit shown is the current through inductor L1.

[0030] Thus, after acquiring the output current of each IGBT inverter branch, the central control processing unit can calculate the current imbalance of each branch. The process is as follows: The central control processing unit is used to synchronously sample the detection signals output by each current sampling unit to obtain the real-time current of each IGBT inverter branch. Based on the real-time current, it calculates the current imbalance of each IGBT inverter branch. When the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, it calculates the gate drive voltage of each IGBT inverter branch based on the real-time current of each IGBT inverter branch.

[0031] Finally, the central control processing unit can generate voltage regulation signals for each IGBT inverter branch based on each gate drive voltage, and transmit each voltage regulation signal to the gate drive unit in the corresponding IGBT inverter branch, so that each gate drive unit adjusts the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage regulation signal, so that after adjustment, the current imbalance of each IGBT inverter branch is less than or equal to the imbalance threshold.

[0032] In specific implementation, the central control processing unit may include, but is not limited to, an ADC unit, a digital filtering unit, a synchronous sampling control unit, an active droop calculation unit, and a drive voltage output unit; wherein, the synchronous sampling control unit is used to trigger the ADC unit to synchronously sample the detection signals output by each current sampling unit at a fixed time in each PWM cycle of any IGBT inverter branch (the PWM cycle of each IGBT inverter branch is the same) to obtain the real-time current of each IGBT inverter branch and transmit it to the active droop calculation unit.

[0033] See Figure 3 As shown ( Figure 3 Still with Figure 1 Taking two IGBT inverter branches as an example to illustrate the current balance optimization control process, when the active droop calculation unit calculates the current imbalance of each branch, the digital filtering unit first filters the real-time current of each IGBT inverter branch, that is, it performs moving average or first-order low-pass filtering on each real-time current to obtain the processed current. Then, the processed current is transmitted to the active droop calculation unit so that the active droop calculation unit can calculate the current imbalance of each IGBT inverter branch based on the processed current.

[0034] Furthermore, the active droop calculation unit first calculates the average current based on the real-time current of each IGBT inverter branch, and then calculates the current imbalance of each IGBT inverter branch based on the average current.

[0035] The detailed calculation process for the current imbalance is disclosed below. When the current imbalance of each IGBT inverter branch is calculated based on the average current, the active droop calculation unit is configured to perform the following operations: (1) calculate the difference between the real-time current corresponding to each IGBT inverter branch and the average current (the processed current is used here) to obtain the current deviation of each IGBT inverter branch; (2) calculate the ratio of the absolute value of each current deviation to the average current to obtain the current imbalance corresponding to each IGBT inverter branch (the process can be found in [link to process]). Figure 3 (As shown).

[0036] Thus, after calculating the current imbalance of each IGBT inverter branch, the current imbalance of each branch can be judged. That is, the active droop calculation unit is also used when the current imbalance of any IGBT inverter branch exceeds the imbalance threshold (see...). Figure 3 As shown, the value can be set to 0.1 (but is not limited to 0.1). Based on the real-time current corresponding to each IGBT inverter branch, the gate drive voltage of each IGBT inverter branch is calculated and transmitted to the drive voltage output unit.

[0037] In specific implementation, the detailed calculation process of the gate drive voltage of each IGBT inverter branch is disclosed below. That is, when the gate drive voltage of each IGBT inverter branch is calculated based on the real-time current corresponding to each IGBT inverter branch, the active droop calculation unit is configured to perform the following operations: Step 1: Obtain the rated gate drive voltage and preset operating current of each IGBT inverter branch.

[0038] Step 2: Calculate the cumulative current error of each IGBT inverter branch within a preset time period, and calculate the integral cumulative error based on the cumulative current error. Also, calculate the real-time current error of each IGBT inverter branch based on the preset operating current and real-time current of each IGBT inverter branch.

[0039] In practical implementation, the cumulative current error can be calculated using an integral method, i.e., the cumulative current error is: , for Current error at time t, The value is [t1, t2], where t1 is the cumulative start time, t2 is the current time, and the duration between the two is the preset duration, such as 1 minute, 2 minutes, or 8 to 15 minutes, etc. In this way, after calculating the cumulative current error, multiplying it by the integral coefficient, the integral cumulative error can be obtained. Of course, the real-time current error is the difference between the real-time current of each IGBT inverter branch and the preset operating current.

[0040] After calculating the real-time current error and the integral cumulative error, the gate drive voltage of each IGBT inverter branch can be calculated by combining the rated gate drive voltage of each IGBT inverter branch. The process is shown in the third step below.

[0041] Step 3: Calculate the gate drive voltage of each IGBT inverter branch based on the real-time current error, integral cumulative error, and rated gate drive voltage of each IGBT inverter branch.

[0042] In practical applications, the gate drive voltage of each IGBT inverter branch can be calculated using, but is not limited to, the following formula.

[0043] ; In the formula, This represents the gate drive voltage of the i-th IGBT inverter branch. This represents the rated gate drive voltage of the i-th IGBT inverter branch. The droop coefficient is... Let be the real-time current error of the i-th IGBT inverter branch. This is the proportionality coefficient. This represents the cumulative integral error of the i-th IGBT inverter branch.

[0044] Therefore, this embodiment uses an active droop control + PI control method to dynamically adjust the gate drive voltage of each IGBT inverter branch. In other words, the central control processing unit also includes a PI controller (see...). Figure 1 (As shown).

[0045] Based on the aforementioned formula, after calculating the gate drive voltage of each IGBT inverter branch, the drive voltage output unit can generate the voltage adjustment signal for each branch. That is, the drive voltage output unit is used to generate the voltage adjustment signal corresponding to each IGBT inverter branch according to the gate drive voltage of each IGBT inverter branch, and transmit it to the gate drive unit in each IGBT inverter branch. This allows each gate drive unit to adjust the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage adjustment signal, so that the current of each parallel IGBT inverter branch tends to be balanced.

[0046] Optionally, for example, the drive voltage output unit can, but is not limited to, convert each gate drive voltage into an analog voltage, and then send it to each gate drive unit through the DAC unit in the DSP, thereby dynamically adjusting the gate drive voltage amplitude of each IGBT inverter branch.

[0047] For specific implementation, see Figure 1 As shown, the gate drive unit described by example may include, but is not limited to, an adjustable gate drive power supply (i.e., Figure 1 Adjustable drive power supply) and gate drive circuit (using Figure 1 (represented by the isolated drive circuit in the diagram). The input terminal of the adjustable gate drive power supply in each IGBT inverter branch is electrically connected to the central control processing unit (i.e., the output pin connected to the DAC unit), and the output terminal of each adjustable gate drive power supply is electrically connected to the power supply input terminal of the gate drive circuit in the corresponding IGBT inverter branch. Thus, the adjustable gate drive power supply is configured to adjust its output voltage according to the drive voltage control command (i.e., voltage adjustment signal) output by the DSP.

[0048] Simultaneously, the controlled terminals of each gate drive circuit are electrically connected to the PWM output pin of the central control processing unit (i.e., the central control processing unit), and the output terminals of each gate drive circuit are electrically connected to the gate of the IGBT power device in the corresponding IGBT inverter branch (i.e., the gate of the IGBT power device). Figure 2 (The gates of Q1-Q4 in the middle), so the gate drive circuit is configured to provide the drive voltage and current required for the corresponding IGBT power devices to turn on and off, thereby completing the dynamic adjustment of the gate drive voltage amplitude.

[0049] Based on this, the dynamic adjustment process of the gate drive voltage amplitude by the DSP is as follows: The central control processing unit is used to transmit each voltage adjustment signal to the adjustable gate drive power supply in the corresponding IGBT inverter branch, so that each adjustable gate drive power supply adjusts the output voltage of each gate drive circuit according to the received voltage adjustment signal, so as to control each gate drive circuit to adjust the gate drive voltage amplitude of its corresponding IGBT inverter branch based on the output voltage.

[0050] Furthermore, as an example, the adjustable gate drive power supply adopts a digitally controlled boost DC-DC converter, whose feedback node is directly controlled by the DAC output of the DSP, thereby realizing continuous adjustment of the gate drive voltage amplitude in the range of 12V to 20V.

[0051] Furthermore, in this embodiment, each gate drive circuit is provided with a fault output pin, and each gate drive circuit is electrically connected to the central control processing unit through the fault output pin. Thus, when the central control processing unit detects that the real-time current corresponding to any IGBT inverter branch is greater than the overcurrent threshold, or when the central control processing unit receives a fault signal sent by the fault output pin of any gate drive circuit, it stops the PWM output of all IGBT inverter branches and adjusts the output voltage of the adjustable gate drive power supply in each IGBT inverter branch to the minimum safe voltage. In this way, welding safety can be guaranteed.

[0052] Additionally, in this embodiment, the central control processing unit may also include, but is not limited to, a hysteresis comparison unit, wherein the hysteresis comparison unit is used when the current imbalance in all IGBT inverter branches is lower than a preset threshold (see...). Figure 3 As shown, it can be set to 0.05), pausing the welding current balance optimization adjustment to avoid control oscillation; of course, this hysteresis comparison can be selected and set according to actual use, and whether it is set or not does not affect the current balance control of each branch.

[0053] Therefore, by repeating the aforementioned operation, dynamic closed-loop control of the gate drive voltage of each IGBT inverter branch can be completed, thereby balancing the current of each IGBT inverter branch.

[0054] Therefore, the overall workflow for optimizing welding current balance is as follows: The DSP's PWM module generates PWM signals to drive the parallel IGBT inverter branches. At a fixed time in each PWM cycle, the synchronous sampling control unit triggers the ADC to synchronously sample the output voltage of all Hall current sensors to obtain the real-time current value of each branch.

[0055] Then, the DSP performs digital filtering on the current values ​​of each branch to obtain the filtered current values.

[0056] Next, the DSP calculates the average current value of all IGBT inverter branches and the current deviation of each branch, so as to calculate the current imbalance of each IGBT inverter branch based on the current deviation.

[0057] Furthermore, when the current imbalance of any branch exceeds the preset imbalance threshold, the DSP uses an active droop and PI control algorithm to calculate the gate drive voltage value required for each branch.

[0058] Finally, the DSP converts the calculated gate drive voltage values ​​into DAC output codes, and controls the corresponding adjustable gate drive power supply through the DAC to adjust its output voltage, thereby dynamically adjusting the gate drive voltage amplitude of each IGBT branch and making the current of each parallel IGBT inverter branch tend to be balanced.

[0059] Repeat the above operations to form a closed-loop control until the welding is completed.

[0060] Therefore, based on the detailed explanation of welding current balance optimization above, this invention sets up current sampling units in each IGBT inverter branch to collect their respective output currents in real time. The central control processing unit synchronously samples and calculates the current imbalance of each branch. When the imbalance of a branch exceeds the limit, the central control processing unit accurately calculates the required gate drive voltage based on the real-time current of each branch and generates a voltage adjustment signal to control the corresponding gate drive unit, thereby dynamically adjusting the gate drive voltage amplitude of the IGBT full bridge in each branch, thus reducing the current imbalance of each branch to within the threshold. Thus, this invention achieves active equalization adjustment of the output current of multiple IGBT inverter branches, effectively solving the problem of uneven current distribution caused by differences in device parameters, avoiding overheating or output distortion in some modules, significantly improving arc stability, and thus suppressing welding defects such as undercut and humps. As a result, this invention can ensure stable welding of ultra-long welds for hundreds of hours continuously, greatly reducing rework costs, improving production efficiency, and eliminating dependence on imported welding power supplies, thereby providing reliable technical support for national energy infrastructure and high-end equipment manufacturing. Therefore, this invention is very suitable for large-scale application and promotion.

[0061] like Figure 4 As shown, the second aspect of this embodiment provides a welding current balance optimization method, wherein the method is executed based on the welding current balance optimization module described in the first aspect of the embodiment, and the operation steps of the method may be, but are not limited to, the steps S1 to S3 below.

[0062] S1. The current sampling unit in each IGBT inverter branch collects the output current on the IGBT full bridge in its corresponding IGBT inverter branch and generates a detection signal to be output to the central control processing unit.

[0063] S2. The central control processing unit synchronously samples the detection signals output by each current sampling unit to obtain the real-time current of each IGBT inverter branch. Based on the real-time current, it calculates the current imbalance of each IGBT inverter branch. When the current imbalance of any IGBT inverter branch exceeds the imbalance threshold, it calculates the gate drive voltage of each IGBT inverter branch based on the real-time current corresponding to each IGBT inverter branch.

[0064] S3. The central control processing unit generates voltage regulation signals for each IGBT inverter branch based on each gate drive voltage, and transmits each voltage regulation signal to the gate drive unit in the corresponding IGBT inverter branch, so that each gate drive unit adjusts the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage regulation signal, so that after adjustment, the current imbalance of each IGBT inverter branch is less than or equal to the imbalance threshold.

[0065] The working process, working details and technical effects of the method provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0066] The third aspect of this embodiment provides a welding current balance optimization device, taking the device electronic equipment as an example, including: a memory, a processor and a transceiver connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the welding current balance optimization method as described in the second aspect of the embodiment.

[0067] For specific examples, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out (FIFO) memory, and / or first-in-last-out (FILO) memory, etc.; specifically, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented using at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor, also known as the CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state.

[0068] In some embodiments, the processor may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. For example, the processor may not be limited to microprocessors of the STM32F105 series, reduced instruction set computer (RISC) microprocessors, x86 architecture processors, or processors with integrated neural network processing units (NPUs). The transceiver may be, but is not limited to, a Wi-Fi transceiver, a Bluetooth transceiver, a General Packet Radio Service (GPRS) transceiver, a ZigBee (a low-power LAN protocol based on the IEEE 802.15.4 standard) transceiver, a 3G transceiver, a 4G transceiver, and / or a 5G transceiver. Furthermore, the device may also include, but is not limited to, a power module, a display screen, and other necessary components.

[0069] The working process, working details and technical effects of the electronic device provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0070] The fourth aspect of this embodiment provides a storage medium that stores instructions containing the welding current balance optimization method described in the second aspect of the embodiment. That is, the storage medium stores instructions that, when executed on a computer, perform the welding current balance optimization method as described in the second aspect of the embodiment.

[0071] The storage medium refers to a carrier for storing data, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or memory sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0072] The working process, working details and technical effects of the storage medium provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0073] The fifth aspect of this embodiment provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the welding current balance optimization method as described in the second aspect of this embodiment, wherein the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0074] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A welding current balance optimization module, characterized in that, include: The central control processing unit and at least two parallel IGBT inverter branches, wherein each IGBT inverter branch includes a current sampling unit, a gate drive unit and an IGBT full bridge; The current sampling unit in each IGBT inverter branch is used to collect the output current on the IGBT full bridge in its corresponding IGBT inverter branch and generate a detection signal to be output to the central control processing unit. The central control processing unit is used to synchronously sample the detection signals output by each current sampling unit to obtain the real-time current of each IGBT inverter branch, and calculate the current imbalance of each IGBT inverter branch based on each real-time current. When the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, the gate drive voltage of each IGBT inverter branch is calculated based on the real-time current of each IGBT inverter branch. The central control processing unit is also used to generate voltage regulation signals for each IGBT inverter branch according to each gate drive voltage, and transmit each voltage regulation signal to the gate drive unit in the corresponding IGBT inverter branch, so that each gate drive unit adjusts the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage regulation signal, so that after adjustment, the current imbalance of each IGBT inverter branch is less than or equal to the imbalance threshold.

2. The welding current balance optimization module according to claim 1, characterized in that, The central control processing unit includes: an ADC unit, a synchronous sampling control unit, an active droop calculation unit, and a drive voltage output unit; The synchronous sampling control unit is used to trigger the ADC unit to synchronously sample the detection signals output by each current sampling unit at a fixed time in each PWM cycle of any IGBT inverter branch, so as to obtain the real-time current of each IGBT inverter branch and transmit it to the active droop calculation unit. An active droop calculation unit is used to calculate the average current based on the real-time current of each IGBT inverter branch, and to calculate the current imbalance of each IGBT inverter branch based on the average current. The active droop calculation unit is also used to calculate the gate drive voltage of each IGBT inverter branch based on the real-time current of each IGBT inverter branch when the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, and transmit it to the drive voltage output unit. The drive voltage output unit is used to generate voltage regulation signals corresponding to each IGBT inverter branch based on the gate drive voltage of each IGBT inverter branch.

3. The welding current balance optimization module according to claim 2, characterized in that, When the current imbalance of each IGBT inverter branch is calculated based on the average current, the active droop calculation unit is configured as follows: The difference between the real-time current and the average current corresponding to each IGBT inverter branch is calculated to obtain the current deviation of each IGBT inverter branch. The ratio of the absolute value of each current deviation to the average current is calculated to obtain the current imbalance degree corresponding to each IGBT inverter branch.

4. The welding current balance optimization module according to claim 2, characterized in that, When the gate drive voltage of each IGBT inverter branch is calculated based on the real-time current corresponding to each IGBT inverter branch, the active droop calculation unit is configured as follows: Obtain the rated gate drive voltage and preset operating current of each IGBT inverter branch; The cumulative current error of each IGBT inverter branch within a preset time period is calculated, and the integral cumulative error is calculated based on the cumulative current error. The real-time current error of each IGBT inverter branch is calculated based on the preset operating current and real-time current of each IGBT inverter branch. The gate drive voltage of each IGBT inverter branch is calculated based on the real-time current error, integral cumulative error, and rated gate drive voltage of each IGBT inverter branch.

5. The welding current balance optimization module according to claim 4, characterized in that, The active droop calculation unit is used to calculate the gate drive voltage of each IGBT inverter branch according to the following formula. ； In the formula, This represents the gate drive voltage of the i-th IGBT inverter branch. This represents the rated gate drive voltage of the i-th IGBT inverter branch. The droop coefficient is... Let be the real-time current error of the i-th IGBT inverter branch. This is the proportionality coefficient. This represents the cumulative integral error of the i-th IGBT inverter branch.

6. The welding current balance optimization module according to claim 1, characterized in that, The gate driving unit includes: an adjustable gate driving power supply and a gate driving circuit. The input terminal of the adjustable gate drive power supply in each IGBT inverter branch is electrically connected to the central control processing unit, the output terminal of each adjustable gate drive power supply is electrically connected to the power supply input terminal of the gate drive circuit in the corresponding IGBT inverter branch, the controlled terminal of each gate drive circuit is electrically connected to the PWM output pin of the central control processing unit, and the output terminal of each gate drive circuit is electrically connected to the gate of the IGBT power device in the corresponding IGBT inverter branch. The central control processing unit is used to transmit each voltage adjustment signal to the adjustable gate drive power supply in the corresponding IGBT inverter branch, so that each adjustable gate drive power supply adjusts the output voltage of each gate drive circuit according to the received voltage adjustment signal, so as to control each gate drive circuit to adjust the gate drive voltage amplitude of its corresponding IGBT inverter branch based on the output voltage.

7. A welding current balance optimization module according to claim 6, characterized in that, Each gate drive circuit is also equipped with a fault output pin, and each gate drive circuit is electrically connected to the central control processing unit through the fault output pin. Specifically, when the central control processing unit detects that the real-time current corresponding to any IGBT inverter branch is greater than the overcurrent threshold, or when the central control processing unit receives a fault signal sent by the fault output pin of any gate drive circuit, it stops the PWM output of all IGBT inverter branches and adjusts the output voltage of the adjustable gate drive power supply in each IGBT inverter branch to the minimum safe voltage.

8. The welding current balance optimization module according to claim 1, characterized in that, The current sampling unit includes a Hall current sensor; wherein, the Hall current sensor in each IGBT inverter branch is used to collect the output current on the IGBT full bridge in its corresponding IGBT inverter branch, and convert the collected output current into an analog voltage signal as a detection signal to be output to the central control processing unit.

9. A welding current balance optimization module according to claim 1, characterized in that, The central control processing unit is used to perform moving average or first-order low-pass filtering on each real-time current to obtain the processed current, so as to calculate the current imbalance of each IGBT inverter branch based on the processed current.

10. A method for optimizing welding current balance, characterized in that, The method is executed based on the welding current balance optimization module according to any one of claims 1 to 9, wherein the method includes: The current sampling unit in each IGBT inverter branch collects the output current on the IGBT full bridge in its corresponding IGBT inverter branch and generates a detection signal to be output to the central control processing unit. The central control processing unit synchronously samples the detection signals output by each current sampling unit to obtain the real-time current of each IGBT inverter branch. Based on the real-time current, it calculates the current imbalance of each IGBT inverter branch. When the current imbalance of any IGBT inverter branch is greater than the imbalance threshold, it calculates the gate drive voltage of each IGBT inverter branch based on the real-time current corresponding to each IGBT inverter branch. The central control processing unit generates voltage regulation signals for each IGBT inverter branch based on each gate drive voltage, and transmits each voltage regulation signal to the gate drive unit in the corresponding IGBT inverter branch, so that each gate drive unit adjusts the gate drive voltage amplitude of its corresponding IGBT full bridge based on the received voltage regulation signal, so that after adjustment, the current imbalance of each IGBT inverter branch is less than or equal to the imbalance threshold.

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