Abnormal voltage control method in pulse welding process

Abstract

An abnormal voltage control method in a pulse welding process comprises: determining that an abnormal voltage occurs; filtering the pulse output voltage to output a filtered voltage; determining a pulse output average voltage by taking the filtered voltage as the pulse output voltage; and adjusting a pulse period of a next pulse according to the pulse output average voltage. In the abnormal voltage control method in the pulse welding process according to the embodiment of the present disclosure, the influence of the abnormal voltage on the pulse average voltage is excluded by filtering the abnormal voltage, so that the pulse period of the next pulse can be adjusted based on the pulse average voltage, and the problem of unstable arc length caused by the abnormal voltage in the stainless steel pulse welding process is solved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the field of welding, and in particular, to an abnormal voltage control method in a pulse welding process. BACKGROUND

[0002] With the successful application of refining technologies such as AOD, VOD and SS-VOD in the stainless steel smelting process, the modern stainless steel steel system is becoming more and more perfect, meeting the needs of the automobile manufacturing, rail passenger cars and stainless steel product industries, and the pulse MIG welding technology suitable for stainless steel plate has been widely applied.

[0003] Due to the particularity of stainless steel material itself, such as: magnetic, high content of alloying elements, small thermal conductivity coefficient, large linear expansion coefficient, etc., the stainless steel arc control faces many problems. SUMMARY

[0004] At least one embodiment of the present disclosure provides an abnormal voltage control method in a pulse welding process, comprising:

[0005] determining that an abnormal voltage occurs;

[0006] filtering the pulse output voltage to output a filtered voltage;

[0007] determining a pulse output average voltage by taking the filtered voltage as the pulse output voltage; and

[0008] adjusting a pulse period of a next pulse according to the pulse output average voltage.

[0009] In an embodiment of the present disclosure, determining that an abnormal voltage occurs comprises:

[0010] continuously sampling the pulse output voltage;

[0011] in a case where a rate of change of the pulse output voltage is less than or equal to a first voltage change rate threshold and the pulse output voltage is less than or equal to a first voltage threshold, determining a short circuit;

[0012] after the short circuit, determining to start an arc in a case where the rate of change of the pulse output voltage is greater than or equal to a second voltage change rate threshold and the pulse output voltage is greater than or equal to a second voltage threshold;

[0013] in a case where the arc is started, if the rate of change of the pulse output voltage is greater than or equal to a third voltage change rate threshold, determining a first average voltage and a second average voltage of the pulse output voltage in two consecutive first time intervals; and

[0014] In a case where the first average voltage is greater than or equal to the pulse peak actual voltage or the first reference voltage, and the second average voltage is greater than or equal to the pulse peak actual voltage or the first reference voltage, it is determined that the abnormal voltage occurs.

[0015] In one embodiment of the present disclosure, the filtering processing on the pulse output voltage comprises:

[0016] a difference between the pulse base value average voltage of the last cycle and the first voltage compensation amount is taken as the filtering voltage; and

[0017] In a case where the pulse output voltage is less than or equal to the third voltage threshold, the pulse output voltage is taken as the filtering voltage.

[0018] In one embodiment of the present disclosure, the abnormal voltage control method in the pulse welding process further comprises:

[0019] In a case where the pulse output voltage is less than or equal to the third voltage threshold, a first current pulse is output within a first time length, a peak current of the first current pulse is a sum of the pulse base value current and the first compensation current, and a base value current of the first current pulse is the pulse base value current.

[0020] In one embodiment of the present disclosure, the determination of the abnormal voltage comprises:

[0021] the pulse output voltage is continuously sampled; and

[0022] In a case where a change rate of the pulse output voltage is greater than or equal to a fourth voltage change rate threshold, and the pulse output voltage is greater than or equal to a fourth voltage threshold or greater than or equal to the pulse peak actual voltage, it is determined that the abnormal voltage occurs.

[0023] In one embodiment of the present disclosure, the filtering processing on the pulse output voltage comprises:

[0024] a difference between the pulse base value average voltage of the last cycle and the second voltage compensation amount is taken as the filtering voltage;

[0025] In a case where the pulse output voltage is less than the fourth voltage threshold, the pulse output voltage is taken as the filtering voltage.

[0026] In one embodiment of the present disclosure, the abnormal voltage control method in the pulse welding process further comprises:

[0027] In a case where the pulse output voltage is less than or equal to the fourth voltage threshold, a second current pulse is output within a second time length, a peak current of the second current pulse is a sum of the pulse base value current and the second compensation current, and a base value current of the second current pulse is the pulse base value current.

[0028] At least one embodiment of the present disclosure further provides a non-volatile storage medium having stored thereon a computer program executable by a processor, in response to the processor executing the computer program, the processor is configured to implement the operations in the abnormal voltage control method in any one of the pulse welding processes described above.

[0029] At least one embodiment of the present disclosure further provides a computer program product comprising a processor executable program computer program, when the computer program is executed by a processor, the processor is configured to implement the operations in the abnormal voltage control method in any one of the pulse welding processes described above.

[0030] In the method and device for controlling abnormal voltage according to the embodiments of the present disclosure, by filtering the abnormal voltage, the influence of the abnormal voltage on the pulse average voltage is excluded, so that the pulse period of the next pulse can be adjusted based on the pulse average voltage, and the problem of unstable arc length caused by abnormal voltage in the stainless steel pulse welding process is solved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The situation of abnormal voltage after short circuit in the pulse output process is shown;

[0032] Figure 2 The situation of abnormal voltage without short circuit in the pulse output process is shown;

[0033] Figure 3 The flow chart of the method for controlling abnormal voltage according to an embodiment of the present disclosure is shown;

[0034] Figure 4 The flow chart of determining abnormal voltage in the method for controlling abnormal voltage according to an embodiment of the present disclosure is shown;

[0035] Figure 5 The flow chart of filtering in the method for controlling abnormal voltage according to another embodiment of the present disclosure is shown;

[0036] Figure 6 The flow chart of determining abnormal voltage in the method for controlling abnormal voltage according to another embodiment of the present disclosure is shown; and

[0037] Figure 7 The flow chart of filtering in the method for controlling abnormal voltage according to another embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0038] The present disclosure will be further described in detail by the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present disclosure will become clearer and more explicit.

[0039] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The disclosure can lie in various sub-combinations of the various features described herein.

[0040] In addition, the technical features involved in different embodiments of the disclosure described below can be combined with each other as long as there is no conflict.

[0041] Pulse MIG welding technology is very suitable for welding stainless steel products. However, due to the characteristics of stainless steel materials, such as magnetism, high alloy element content, small thermal conductivity coefficient, and large linear expansion coefficient, many problems are encountered in arc control during welding of stainless steel, one of which is how to determine the pulse arc length during welding.

[0042] Whether the arc length is stable during welding will directly affect the welding quality. The traditional pulse arc control is to use the pulse average voltage AvgV of a pulse cycle as the basis for determining the arc length. Generally, when the pulse average voltage AvgV is greater than the set voltage SetV, it is determined that the arc length is increased, and the pulse cycle T will be increased in the next pulse cycle to adjust to the appropriate arc length; otherwise, when the pulse average voltage AvgV is lower than the set voltage SetV, it is determined that the arc length is reduced, and the pulse cycle T will be reduced in the next pulse cycle to adjust to the appropriate arc length.

[0043] However, it is found in a large number of welding practices that when there is an abnormal voltage in the pulse, the pulse average voltage AvgV of a pulse cycle cannot reflect the true arc length. Especially in the process of welding stainless steel materials, when there is an abnormal voltage in the pulse, the pulse cycle average voltage AvgV will be significantly increased. However, due to the existence of abnormal voltage, the arc is unstable, the amount of wire melting is reduced, and thus the arc length is shortened and the droplet transfer is difficult in the next pulse. At this time, if the pulse cycle is continued to be reduced in the next pulse process, it will lead to difficulty in droplet detachment, thereby affecting the stability of the arc. In view of the above situation, a new pulse arc control method needs to be researched.

[0044] Generally, in the pulse welding process, the abnormal voltage can be divided into two types according to the timing of the abnormal voltage: ① the abnormal voltage is generated when the arc is ignited after the short circuit occurs; ② the abnormal voltage is suddenly generated in the base current stage, although no short circuit occurs. The timing, frequency, size and duration of the abnormal voltage in the stainless steel MIG pulse welding process will directly affect the stability of the welding arc and the welding quality. The traditional pulse arc control is based on the average voltage AvgV of a pulse cycle as the basis for determining the arc length. When the average voltage AvgV of a pulse cycle is higher than the set voltage SetV, it is determined that the arc length is increased, and the pulse cycle T is increased in the next pulse cycle to adjust to the appropriate arc length. Conversely, when the average voltage AvgV of a pulse cycle is lower than the set voltage SetV, it is determined that the arc length is decreased, and the pulse cycle T is decreased in the next pulse cycle to adjust to the appropriate arc length. However, through a large number of welding verifications, it is found that when the abnormal voltage occurs in the pulse cycle, the average voltage of a pulse cycle cannot reflect the true arc length, especially when the abnormal voltage exists in the stainless steel welding process, the average voltage of a pulse cycle will increase significantly. However, due to the existence of the abnormal voltage, the arc is unstable, the amount of wire melting decreases, and then the arc length becomes shorter and the droplet transfer is difficult in the next pulse, at this time, if the cycle is further reduced, it will lead to the difficulty of droplet detachment, thereby affecting the stability of the arc.

[0045] Figure 1 and Figure 2 respectively show two situations of the abnormal voltage. As shown in Figure 1 , a short circuit occurs in the T4 time period, and after the short circuit, an abnormal voltage V2 occurs when the arc is ignited. As shown in Figure 2 , no short circuit occurs in the process of outputting the pulse, but an abnormal voltage V3 occurs when the base voltage is output.

[0046] In order to detect and control the abnormal voltage that occurs in different situations, at least one embodiment of the present disclosure provides an abnormal voltage control method in a pulse welding process.

[0047] At least one embodiment of the present disclosure provides an abnormal voltage control method in a pulse welding process, as shown in Figure 3 , the abnormal voltage control method in the pulse welding process comprises:

[0048] S01, determining that the abnormal voltage occurs;

[0049] S02, filtering the pulse output voltage to output a filtered voltage;

[0050] S03, determining the pulse output average voltage by taking the filtered voltage as the pulse output voltage; and

[0051] S04, adjusting the pulse period of the next pulse according to the average voltage of the pulse output.

[0052] In one embodiment of the present disclosure, as shown in Figure 4 Determining whether an abnormal voltage occurs in the pulse output voltage includes:

[0053] S0101, continuously sampling the pulse output voltage;

[0054] S0102, in the case that the rate of change of the pulse output voltage is less than or equal to a first voltage rate threshold and the pulse output voltage is less than or equal to a first voltage threshold, determining a short circuit;

[0055] S0103, after the short circuit, determining to start an arc in the case that the rate of change of the pulse output voltage is greater than or equal to a second voltage rate threshold and the pulse output voltage is greater than or equal to a second voltage threshold;

[0056] S0104, in the case that the arc starts, if the rate of change of the pulse output voltage is greater than or equal to a third voltage rate threshold, determining a first average voltage and a second average voltage of the pulse output voltage in two consecutive first time intervals; and

[0057] S0105, in the case that the first average voltage is greater than or equal to a pulse peak actual voltage or a first reference voltage and the second average voltage is greater than or equal to the pulse peak actual voltage or the first reference voltage, determining that an abnormal voltage occurs.

[0058] As shown in Figure 1 One pulse output period is divided into four stages, T1, T2, T3 and T4, wherein T1 is an arc starting stage, T2 is a pulse peak voltage output stage, T3 is an arc ending stage, and T4 is a pulse base value output stage. In the arc starting stage, the pulse output voltage and the pulse output current start to rise rapidly, in the pulse peak voltage output stage, the pulse peak voltage and the pulse peak current are output, in the arc ending stage, the pulse output voltage and the pulse output current rapidly decrease, and in the pulse base value output stage, the pulse base value voltage and the pulse base value current are output.

[0059] In the pulse output process, an abnormal voltage occurs in two cases, one of which occurs after the arc starts after a short circuit, and the other of which occurs in the base value current stage, although no short circuit occurs, but an abnormal voltage is suddenly generated.

[0060] As shown in Figure 1 In the T4 time period, the case that an abnormal voltage occurs after a short circuit occurs. In actual welding, the pulse output voltage is usually continuously sampled every 12.5us. When a short circuit occurs, the voltage rate of change is less than or equal to the first voltage rate threshold, and the voltage is less than or equal to the first voltage threshold, as shown in Figure 1As shown, in the T4 time period, the short circuit occurs, the voltage rate of change is less than or equal to the first voltage rate of change threshold, that is, dv / dt≤K0, and the pulse output voltage also drops to less than or equal to the first voltage threshold, that is, V≤V0. After the short circuit occurs, the arc burning starts, at this time, the pulse output voltage starts to rise rapidly, and the voltage rate of change is less than or equal to the second voltage rate of change threshold, and the pulse output voltage is greater than the second voltage threshold, that is, dv / dt≥K1 and V≥V1. When the arc is burning, if the voltage rate of change is greater than or equal to the third voltage rate of change threshold, that is, dv / dt≥K2, the first average voltage and the second average voltage of the pulse output voltage in the continuous two first time intervals are determined, and if the first average voltage is greater than or equal to the pulse peak actual voltage or the first reference voltage, and the second average voltage is greater than or equal to the pulse peak actual voltage or the first reference voltage, it is determined that the abnormal voltage occurs.

[0061] Generally, the abnormal voltage is that the pulse output voltage exceeds the pulse peak actual voltage. However, in many cases, for example, when welding aluminum or stainless steel materials, the pulse peak actual voltage is much smaller, at this time, if the pulse peak voltage is greater than the first reference voltage, the abnormal voltage also occurs.

[0062] After it is determined that the abnormal voltage occurs, the pulse output voltage is filtered to output a filtered voltage.

[0063] In an embodiment of the present disclosure, as shown in Figure 5 The filtering of the pulse output voltage includes:

[0064] S0201, the difference between the pulse base value average voltage of the last period and the first voltage compensation amount is taken as the filtered voltage; and

[0065] S0202, in the case where the pulse output voltage is less than or equal to the third voltage threshold, the pulse output voltage is taken as the filtered voltage.

[0066] As shown in Figure 1 After the abnormal voltage occurs in the arc burning stage after the short circuit, the filtering of the pulse output voltage is performed, first, the difference between the pulse base value average voltage of the last period and the first voltage compensation amount AV1 is taken as the pulse output voltage, after the abnormal voltage occurs, the pulse output voltage gradually decreases, in the case where the pulse output voltage decreases to less than the third voltage threshold, the pulse output voltage is taken as the pulse output voltage.

[0067] After the abnormal voltage occurs, the average voltage of the pulse in the pulse period is determined by filtering the abnormal voltage and replacing the abnormal voltage with the filtered voltage. The average voltage of the pulse thus determined and the set voltage are compared as the basis for determining the arc length, which can reflect the actual arc length, and thus the pulse period of the next pulse can be accurately adjusted.

[0068] In one embodiment of the present disclosure, in order to compensate for the decrease in output energy caused by reducing the pulse output voltage, when the pulse output voltage is less than or equal to the third voltage threshold, a first current pulse is output within a first time length, the peak current of the first current pulse is the sum of the pulse base current and the first compensation current, and the base current of the first current pulse is the pulse base current corresponding to the set welding current. By outputting the current pulse, the problem of output energy reduction caused by filtering the pulse output voltage is compensated for, the amount of welding wire melting can be increased, and poor welding can be avoided.

[0069] In Figure 2 It is shown that the abnormal voltage occurs in the T4 time period when there is no short circuit. As Figure 2 shown, when the voltage rate of change is greater than or equal to the fourth voltage rate of change threshold K3, and the pulse output voltage is greater than or equal to the fourth voltage threshold V c or greater than or equal to the pulse peak actual voltage, i.e., dv / dt≥K3 and V≥V c , the abnormal voltage occurs.

[0070] In one embodiment of the present disclosure, as Figure 6 shown, determining that the abnormal voltage occurs includes:

[0071] S0111, continuously sampling the pulse output voltage; and

[0072] S0112, determining that the abnormal voltage occurs when the rate of change of the pulse output voltage is greater than or equal to the fourth voltage rate of change threshold and the pulse output voltage is greater than or equal to the fourth voltage threshold or greater than or equal to the pulse peak actual voltage.

[0073] After it is determined that the abnormal voltage occurs, the pulse output voltage is filtered and a filtered voltage is output.

[0074] In one embodiment of the present disclosure, as Figure 7 shown, filtering the pulse output voltage includes:

[0075] S0211, when the abnormal voltage occurs, the difference between the pulse base average voltage of the last cycle and the second voltage compensation amount is taken as the filtered voltage; and

[0076] S0212, when the pulse output voltage is less than or equal to the fourth voltage threshold, the pulse output voltage is used as the filter voltage.

[0077] like Figure 2 As shown, when an abnormal voltage is determined to occur, that is, when the voltage change rate is greater than or equal to the fourth voltage change rate threshold K3, and the pulse output voltage is greater than or equal to the fourth voltage threshold V, the abnormal voltage is determined to occur. c Or when it is greater than or equal to the actual voltage of the pulse peak, that is, when dv / dt≥K3 and V≥V c When an abnormal voltage occurs, the difference between the average voltage of the pulse base value of the previous cycle and the second voltage compensation amount is used as the filter voltage. After an abnormal voltage occurs, the pulse output voltage will gradually return to normal. When the pulse output voltage is less than or equal to the fourth voltage threshold, the pulse output voltage is used as the filter voltage.

[0078] After an abnormal voltage occurs, the abnormal voltage is filtered and replaced with the filtered voltage to determine the average pulse voltage within the pulse cycle. This determined average pulse voltage is compared with the set voltage as the basis for determining the arc length, reflecting the true arc length and allowing for accurate adjustment of the pulse cycle of the next pulse.

[0079] In one embodiment of this disclosure, to compensate for the reduction in output energy caused by lowering the pulse output voltage, a second current pulse is output within a second time period when the pulse output voltage is less than or equal to a fourth voltage threshold. The peak current of the second current pulse is the sum of the pulse base current and the second compensation current, and the base current of the second current pulse is the pulse base current. By outputting a current pulse, the problem of reduced output energy caused by filtering the pulse output voltage is compensated for, thereby increasing the amount of welding wire melting and avoiding poor welding.

[0080] In the abnormal voltage control method during pulse welding according to this disclosure, the values ​​of the first voltage change rate threshold, second voltage change rate threshold, third voltage change rate threshold, fourth voltage change rate threshold, first voltage threshold, second voltage threshold, third voltage threshold, fourth voltage threshold, first compensation voltage, second compensation voltage, first compensation current, second compensation current, pulse base current, pulse peak current, pulse base voltage, and pulse peak voltage will vary depending on the welding material, wire diameter, shielding gas, and welding current value. Appropriate parameters need to be determined according to the specific circumstances.

[0081] In the abnormal voltage control method during pulse welding according to the embodiments of the present disclosure, the abnormal voltage is filtered to eliminate the influence of the abnormal voltage on the average pulse voltage. This allows the pulse period of the next pulse to be adjusted based on the average pulse voltage, thus solving the problem of arc length instability caused by abnormal voltage during stainless steel pulse welding.

[0082] At least one embodiment of the present disclosure also provides a non-volatile storage medium having stored thereon a processor-executable computer program, in response to the processor executing the computer program, the processor is configured to implement the operations in the abnormal voltage control method in any one of the above pulse welding processes.

[0083] At least one embodiment of the present disclosure also provides a computer program product, the computer program product comprising a processor-executable program computer program, when the computer program is executed by the processor, the processor is configured to implement the operations in the abnormal voltage control method in any one of the above pulse welding processes.

[0084] In the description of the present disclosure, it should be explained that the terms “upper”, “lower”, “inner”, “outer”, “front”, “back”, “left”, “right” and the like indicate the orientation or positional relationship based on the working state of the present disclosure, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation to the present disclosure.

[0085] In the description of the present disclosure, it should be explained that the terms “mounting”, “connecting”, “connection” should be understood in a broad sense unless otherwise specifically defined and limited. For those skilled in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0086] The above describes the present disclosure in combination with the preferred embodiments, but these embodiments are only exemplary and are only for illustrative purposes. On this basis, various substitutions and improvements can be made to the present disclosure, which all fall within the protection scope of the present disclosure.

Claims

1. An abnormal voltage control method in a pulse welding process, comprising: determining that an abnormal voltage occurs; filtering the pulse output voltage to output a filtered voltage; determining a pulse output average voltage using the filtered voltage as the pulse output voltage; and adjusting a pulse period of a next pulse according to the pulse output average voltage; wherein the determining that the abnormal voltage occurs includes determining whether the abnormal voltage occurs in a short circuit condition and determining whether the abnormal voltage occurs in a non-short circuit condition; the determining whether the abnormal voltage occurs in the short circuit condition includes: continuously sampling the pulse output voltage; in a case where a rate of change of the pulse output voltage is less than or equal to a first voltage rate threshold and the pulse output voltage is less than or equal to a first voltage threshold, determining that a short circuit occurs; after the short circuit, in a case where the rate of change of the pulse output voltage is greater than or equal to a second voltage rate threshold and the pulse output voltage is greater than or equal to a second voltage threshold, determining that an arc strike starts; in the case where the arc strike starts, if the rate of change of the pulse output voltage is greater than or equal to a third voltage rate threshold, determining a first average voltage and a second average voltage of the pulse output voltage in two consecutive first time intervals; and in a case where the first average voltage is greater than or equal to a pulse peak actual voltage or a first reference voltage and the second average voltage is greater than or equal to the pulse peak actual voltage or the first reference voltage, determining that the abnormal voltage occurs; the determining whether the abnormal voltage occurs in the non-short circuit condition includes: continuously sampling the pulse output voltage; and in a case where the rate of change of the pulse output voltage is greater than or equal to a fourth voltage rate threshold and the pulse output voltage is greater than or equal to a fourth voltage threshold or a pulse peak actual voltage, determining that the abnormal voltage occurs. if it is determined that the abnormal voltage occurs in the short circuit condition, the filtering the pulse output voltage includes:

2. The method of abnormal voltage control in a pulsed welding process of claim 1, wherein, using a difference between a pulse base value average voltage of a previous cycle and a first voltage compensation amount as the filtered voltage; and in a case where the pulse output voltage is less than or equal to a third voltage threshold, using the pulse output voltage as the filtered voltage.

3. The abnormal voltage control method in a pulse welding process according to claim 2, further comprising: in a case where the pulse output voltage is less than or equal to the third voltage threshold, outputting a first current pulse in a first time length, a peak current of the first current pulse being a sum of a pulse base value current and a first compensation current, a base value current of the first current pulse being the pulse base value current. if it is determined that the abnormal voltage occurs in the non-short circuit condition, the filtering the pulse output voltage includes:

4. The method of abnormal voltage control in a pulsed welding process of claim 1, wherein, using a difference between a pulse base value average voltage of a previous cycle and a second voltage compensation amount as the filtered voltage; and in a case where the pulse output voltage is less than a fourth voltage threshold, using the pulse output voltage as the filtered voltage.

5. The abnormal voltage control method in a pulse welding process according to claim 4, further comprising: in a case where the pulse output voltage is less than or equal to the fourth voltage threshold, outputting a second current pulse in a second time length, a peak current of the second current pulse being a sum of the pulse base value current and a second compensation current, a base value current of the second current pulse being the pulse base value current. ​ 6. A non-transitory storage medium having stored thereon a processor executable computer program, in response to execution of the computer program by a processor, the processor is configured to implement the operations in the abnormal voltage control method in the pulsed welding process of any one of claims 1 to 5.

7. A computer program product comprising a processor executable computer program, in response to execution of the computer program by a processor, the processor is configured to implement the operations in the abnormal voltage control method in the pulsed welding process of any one of claims 1 to 5.

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