An adjustable PWM signal generation circuit and a welding machine

Abstract

This invention discloses an adjustable PWM signal generation circuit and a welding machine, including a first waveform modulation module, a second waveform modulation module, and a PWM modulation module. The first waveform modulation module can output a first square wave signal and is provided with a first modulation section, which can modulate a first property of the first square wave signal. The second waveform modulation module can output a second square wave signal and is connected to the first waveform modulation module so that the second square wave signal has the same period as the first square wave signal. The second waveform modulation module is provided with a second modulation section, which can modulate a second property of the second square wave signal. The PWM modulation module is connected to the first waveform modulation module and the second waveform modulation module respectively to modulate multiple PWM signals according to the first property and the second property. This design utilizes a modular structure that is easy to adjust according to actual conditions and is flexible in use.

Description

Technical Field

[0001] This invention relates to the field of welding machine technology, and in particular to an adjustable PWM signal generation circuit and a welding machine. Background Technology

[0002] Traditional welding machine drive circuits typically include a PWM signal modulation chip and an inverter circuit. The inverter circuit consists of four switching transistors. The PWM signal modulation chip modulates the corresponding PWM signal according to the requirements and outputs it to each switching transistor to control the switching transistors to turn on and off, thereby adjusting the frequency and voltage of the power supply that powers the welding torch of the welding machine.

[0003] In the past, PWM signal modulation chips were all integrated chips. When PWM signal modulation was required, corresponding control logic needed to be set for software control. When the PWM signal modulation chip failed, the entire chip needed to be replaced, which was costly and inflexible. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an adjustable PWM signal generation circuit and a welding machine. The modular structure is easy to adjust according to actual conditions, making it flexible in use and reducing construction costs.

[0005] An adjustable PWM signal generating circuit according to a first aspect of the present invention includes: a first waveform modulation module capable of outputting a first square wave signal, the first waveform modulation module being provided with a first modulation section, the first modulation section being capable of modulating a first property of the first square wave signal, wherein the first property includes at least one of pulse width and period; a second waveform modulation module capable of outputting a second square wave signal, the second waveform modulation module being connected to the first waveform modulation module such that the second square wave signal has the same period as the first square wave signal, the second waveform modulation module being provided with a second modulation section, the second modulation section being capable of modulating a second property of the second square wave signal, wherein the second property includes the interval time between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal; and a PWM modulation module being connected to the first waveform modulation module and the second waveform modulation module respectively to modulate a plurality of PWM signals according to the first property and the second property.

[0006] An adjustable PWM signal generating circuit according to an embodiment of the present invention has at least the following beneficial effects: This invention discloses an adjustable PWM signal generation circuit, constructed using modular combinations of a first waveform modulation module, a second waveform modulation module, and a PWM modulation module. The first modulation unit modulates the pulse width or period of the first square wave signal output by the first waveform modulation module, forming a first property. The second waveform modulation module generates a second square wave signal and simultaneously acquires the first square wave signal. Utilizing the first property of the first square wave signal, the second square wave signal is made to have the same period as the first square wave signal. The second modulation unit can phase-shift the second square wave signal output by the second waveform modulation module, thereby adjusting the period of the second square wave signal. The time interval between edge triggering and edge triggering of the first square wave signal forms the second property. Both the first and second square wave signals are input into the PWM modulation module. The PWM modulation module can generate one set of PWM signals according to the first property. By using the second property to phase-shift one set of PWM signals, another set of PWM signals can be generated. The two sets of PWM signals have the same period and can be used to drive the inverter module of the welding machine. Both the first and second properties are adjustable, thereby controlling the operation of the inverter module. This design utilizes a modular structure that is easy to adjust according to actual conditions, making it flexible to use and reducing construction costs.

[0007] According to some embodiments of the present invention, the first modulation unit includes a first energy storage unit and a first given port, and the first waveform modulation module further includes a first energy dissipation unit, a trigger unit, and a first contact level converter. The first given port is used to connect to a first given input source. The first energy storage unit is connected to the first given port, the input terminal of the first energy dissipation unit, and the contact terminal of the first contact level converter. The first contact level converter can change the level of the output signal of the first contact level converter to form a first square wave signal according to the input signal received by the contact terminal of the first contact level converter. The output terminal of the first contact level converter is connected to the input terminal of the trigger unit and the PWM modulation module. The output terminal of the trigger unit is connected to the controlled terminal of the first energy dissipation unit to control the first energy dissipation unit to dissipate the energy of the first energy storage unit.

[0008] According to some embodiments of the present invention, the first energy storage unit includes a first variable resistor assembly and a capacitor. One end of the first variable resistor assembly is connected to a first given port, and one end of the capacitor is connected to the other end of the first variable resistor assembly, the input terminal of the first energy dissipation unit, and the contact terminal of the first contact level converter. The other end of the capacitor is grounded.

[0009] According to some embodiments of the present invention, the triggering unit includes a second contact level converter, the output terminal of the first contact level converter is connected to the contact terminal of the second contact level converter, the second contact level converter can change the level of the output signal of the output terminal of the second contact level converter according to the input signal received by the contact terminal of the second contact level converter, and the output terminal of the second contact level converter is connected to the controlled terminal of the first energy dissipation unit.

[0010] According to some embodiments of the present invention, the second modulation unit includes a second energy storage unit, a second given port, and a third given port. The second given port is used to connect to a second given input source, and the third given port is used to connect to a third given input source. The second waveform modulation module includes a comparison unit and a second energy dissipation unit. The second energy storage unit is connected to the second given port, the first input terminal of the comparison unit, and the input terminal of the second energy dissipation unit, respectively. The second input terminal of the comparison unit is connected to the third given port. The comparison unit can compare the input signals received by the first and second input terminals of the comparison unit to change the level of the output signal of the comparison unit. The output terminal of the comparison unit is connected to the PWM modulation module. The controlled terminal of the second energy dissipation unit is connected to the first waveform modulation module to control the second energy dissipation unit to dissipate the energy of the second energy storage unit.

[0011] According to some embodiments of the present invention, the second waveform modulation module further includes a third contact level converter, the contact terminal of the third contact level converter is connected to the output terminal of the comparison unit, the third contact level converter can change the level of the output signal of the third contact level converter to form a second square wave signal according to the input signal received by the contact terminal of the third contact level converter, and the output terminal of the third contact level converter is connected to the PWM modulation module.

[0012] According to some embodiments of the present invention, a current detection module and a switch module are further included. The current detection module is used to sample the output current of the output terminal of the inverter module of the welding machine. The input terminal of the switch module is connected to the second input terminal of the comparison unit and the third given port, respectively. The output terminal of the switch module is grounded. The current detection module is connected to the switch module to control the switching module to turn on and off.

[0013] According to some embodiments of the present invention, the PWM modulation module includes a first PWM modulation unit and a second PWM modulation unit. Both the first and second PWM modulation units include a trigger terminal, a first output terminal, and a second output terminal. The first waveform modulation module is connected to the trigger terminal of the first PWM modulation unit. The first output terminal of the first PWM modulation unit outputs a first PWM signal, and the second output terminal of the second PWM modulation unit outputs a second PWM signal. The first and second PWM signals are complementary, and the first PWM modulation unit controls the first and second PWM signals to flip according to the first property. The second waveform modulation module is connected to the trigger terminal of the second PWM modulation unit. The first output terminal of the second PWM modulation unit outputs a third PWM signal, and the second output terminal of the second PWM modulation unit outputs a fourth PWM signal. The third and fourth PWM signals are complementary, and the second PWM modulation unit controls the third and fourth PWM signals to flip according to the second property.

[0014] According to some embodiments of the present invention, an isolation module is further included, wherein the output terminal of the PWM modulation module is connected to the input terminal of the isolation module, and the output terminal of the isolation module is used to connect to the controlled terminal of the inverter module of the welding machine.

[0015] According to a second aspect of the present invention, the welding machine includes an adjustable PWM signal generating circuit disclosed in any of the above embodiments.

[0016] The welding machine according to embodiments of the present invention has at least the following beneficial effects: The welding machine of this invention utilizes an adjustable PWM signal generation circuit to control the operation of the inverter module of the welding machine, and can modulate the PWM signal used to control the inverter module. This design utilizes a modular structure that is easy to adjust according to actual conditions, making it flexible to use and reducing construction costs.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic block diagram of one embodiment of the PWM signal generation circuit of the present invention; Figure 2 This is the circuit diagram of the first waveform modulation module; Figure 3This is the circuit diagram of the second waveform modulation module; Figure 4 This is the circuit diagram of the PWM modulation module; Figure 5 This is the circuit diagram for the current detection module and the switching module; Figure 6 This is a circuit diagram of the inverter module of the welding machine of the present invention; Figure 7 The waveforms for each node of AF and QA-QD are shown.

[0019] Figure label: The system comprises: a first waveform modulation module 100, a first energy dissipation unit 110, a first contact level converter 120, a trigger unit 130, a second contact level converter 131, a first modulation unit 200, a first energy storage unit 210, a first given port 220, a second waveform modulation module 300, a comparison unit 310, a second energy dissipation unit 320, a third contact level converter 330, a second modulation unit 400, a second energy storage unit 410, a second given port 420, a third given port 430, a PWM modulation module 500, a first PWM modulation unit 510, a second PWM modulation unit 520, an isolation module 600, a current detection module 710, a switching module 720, and an inverter module 800. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be understood that the orientation descriptions, such as the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer", indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1-7 As shown, an adjustable PWM signal generating circuit according to a first aspect embodiment of the present invention includes a first waveform modulation module 100, a second waveform modulation module 300, and a PWM modulation module 500. The first waveform modulation module 100 is capable of outputting a first square wave signal and is provided with a first modulation section 200, which can modulate a first property of the first square wave signal, wherein the first property includes at least one of pulse width and period. The second waveform modulation module 300 is capable of outputting a second square wave signal and is connected to the first waveform modulation module 100 such that the second square wave signal has the same period as the first square wave signal. The second waveform modulation module 300 is provided with a second modulation section 400, which can modulate a second property of the second square wave signal, wherein the second property includes the interval time between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal. The PWM modulation module 500 is connected to the first waveform modulation module 100 and the second waveform modulation module 300 respectively to modulate multiple PWM signals according to the first property and the second property.

[0025] It should be noted that the adjustable PWM signal generation circuit in this design can provide a PWM signal for control of the welding machine, such as... Figure 6 As shown, a typical welding machine includes a first rectifier module, an inverter module 800, a transformer module, a second rectifier module, and a welding torch connected in sequence. The inverter module 800 consists of... Figure 6 The inverter module 800 is composed of switching transistors Qa, Qb, Qc, and Qd. The multiple PWM signals output by the PWM modulation module 500 can be output to the switching transistors Qa, Qb, Qc, and Qd respectively, controlling the on / off state of the switching transistors Qa, Qb, Qc, and Qd, thereby controlling the operation of the inverter module 800.

[0026] The adjustable PWM signal generation circuit of this invention is constructed using a modular combination of a first waveform modulation module 100, a second waveform modulation module 300, and a PWM modulation module 500. The first modulation unit 200 modulates the pulse width or period of the first square wave signal output by the first waveform modulation module 100, forming a first property. The second waveform modulation module 300 generates a second square wave signal. Simultaneously, the second waveform modulation module 300 acquires the first square wave signal and utilizes the first property of the first square wave signal to ensure that the period of the second square wave signal is the same as that of the first square wave signal. The second modulation unit 400 can phase-shift the second square wave signal output by the second waveform modulation module 300, thereby adjusting the pulse width or period of the second square wave signal. The time interval between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal forms the second property. Both the first and second square wave signals are input into the PWM modulation module 500. The PWM modulation module 500 can generate one set of PWM signals according to the first property. By using the second property to phase-shift one set of PWM signals, another set of PWM signals can be generated. The two sets of PWM signals have the same period and can be used to drive the inverter module 800 of the welding machine. Both the first and second properties are adjustable, thereby controlling the operation of the inverter module 800. This design utilizes a modular structure that is easy to adjust according to actual conditions, making it flexible to use and reducing construction costs.

[0027] In some embodiments of the present invention, such as Figure 4 As shown, it also includes an isolation module 600. The output terminal of the PWM modulation module 500 is connected to the input terminal of the isolation module 600. The output terminal of the isolation module 600 is used to connect to the controlled terminal of the inverter module 800 of the welding machine.

[0028] The isolation module 600 isolates the adjustable PWM signal generation circuit of this design from the inverter module 800 of the welding machine, preventing interference generated in the inverter module 800 from affecting the operation of the adjustable PWM signal generation circuit of this design. Specifically, the isolation module 600 can be composed of multiple optocouplers, and the output terminal of the PWM modulation module 500 is connected to each switching transistor through each optocoupler.

[0029] The isolation module 600 can also be a pulse isolation transformer, a magnetic coupler isolator, etc.

[0030] In some embodiments of the present invention, such as Figure 4As shown, the PWM modulation module 500 includes a first PWM modulation unit 510 and a second PWM modulation unit 520. Both the first PWM modulation unit 510 and the second PWM modulation unit 520 include a trigger terminal, a first output terminal, and a second output terminal. The first waveform modulation module 100 is connected to the trigger terminal of the first PWM modulation unit 510. The first output terminal of the first PWM modulation unit 510 outputs a first PWM signal, and the second output terminal of the second PWM modulation unit 520 outputs a second PWM signal. The first PWM signal and the second PWM signal are complementary, and the first PWM modulation unit 510 controls the first PWM signal and the second PWM signal to flip according to a first property. The second waveform modulation module 300 is connected to the trigger terminal of the second PWM modulation unit 520. The first output terminal of the second PWM modulation unit 520 outputs a third PWM signal, and the second output terminal of the second PWM modulation unit 520 outputs a fourth PWM signal. The third PWM signal and the fourth PWM signal are complementary, and the second PWM modulation unit 520 controls the third PWM signal and the fourth PWM signal to flip according to a second property.

[0031] The first PWM modulation unit 510 can generate one set of PWM signals based on the first property, namely, the first PWM signal (i.e., point QA) and the second PWM signal (i.e., point QB). The second PWM modulation unit 520 can generate another set of PWM signals using the second property, namely, the third PWM signal (i.e., point QC) and the fourth PWM signal (i.e., point QD). Specifically, both the first PWM modulation unit 510 and the second PWM modulation unit 520 can be D flip-flops, such as... Figure 4 As shown, taking the first PWM modulation unit 510 as an example, the trigger terminal of the first PWM modulation unit 510 is connected to the output terminal of the first waveform modulation module 100 (i.e., point A), thereby receiving the first square wave signal. The first output terminal and the second output terminal of the first PWM modulation unit 510 respectively output two complementary first PWM signals and second PWM signals, both of which are square waves. When the first square wave signal is edge-triggered (specifically, it can be a rising edge trigger), the first PWM signal and the second PWM signal are simultaneously controlled to flip. Specifically, the signal at point QA corresponds to the switch Qa, the signal at point QB corresponds to the switch Qb, the signal at point QC corresponds to the switch Qc, and the signal at point QD corresponds to the switch Qd.

[0032] In some embodiments of the present invention, such as Figure 2 , 7As shown, the first modulation unit 200 includes a first energy storage unit 210 and a first given port 220. The first waveform modulation module 100 also includes a first energy dissipation unit 110, a trigger unit 130, and a first contact level converter 120. The first given port 220 is used to connect to a first given input source. The first energy storage unit 210 is connected to the first given port 220, the input terminal of the first energy dissipation unit 110, and the contact terminal of the first contact level converter 120. The first contact level converter 120 can change the level of the output signal of the first contact level converter 120 to form a first square wave signal according to the input signal received by the contact terminal of the first contact level converter 120. The output terminal of the first contact level converter 120 is connected to the input terminal of the trigger unit 130 and the PWM modulation module 500. The output terminal of the trigger unit 130 is connected to the controlled terminal of the first energy dissipation unit 110 to control the first energy dissipation unit 110 to dissipate the energy of the first energy storage unit 210.

[0033] The first given port 220 can be connected to an external first given input source, such as a +15V voltage. The first given input source charges the first energy storage unit 210 through the first given port 220. When the stored energy of the first energy storage unit 210 increases to a certain level, the input signal voltage received by the contact terminal of the first contact level converter 120 increases (i.e., point C), which can change the level of the output signal at the output terminal of the first contact level converter 120. For example, when the input signal voltage received by the contact terminal of the first contact level converter 120 increases, the first contact level converter... The output of converter 120 is low (i.e., point A), triggering unit 130, which generates a signal to control the on / off state of first energy dissipation unit 110. When first energy dissipation unit 110 is on, it can dissipate the energy of first energy storage unit 210. When the energy of first energy storage unit 210 is dissipated, the input signal voltage received by the contact terminal of first contact level converter 120 decreases, and the output of first contact level converter 120 outputs a high level. Thus, cyclic operation can generate a first square wave signal at point A. This structure is simple, operates stably, and can generate an accurate first square wave signal. The specific waveform is as follows: Figure 7 As shown.

[0034] In some embodiments of the present invention, such as Figure 2 As shown, the first energy storage unit 210 includes a first variable resistor assembly and a capacitor. One end of the first variable resistor assembly is connected to the first given port 220. One end of the capacitor is connected to the other end of the first variable resistor assembly, the input terminal of the first energy dissipation unit 110, and the contact terminal of the first contact level converter 120. The other end of the capacitor is grounded.

[0035] The first variable resistor component here can change its resistance value, thereby changing the charging time of the capacitor so that the voltage at point C reaches the threshold time that triggers the first contact level converter 120 to change the level of the output signal at the output terminal of the first contact level converter 120. In conjunction with the function of the trigger unit 130, the pulse width or period of the first square wave signal can be adjusted.

[0036] In addition, based on the circuit architecture of this design, different specifications of capacitors can be replaced, which can also be used to adjust the pulse width or period of the first square wave signal.

[0037] Of course, changing the voltage input to the first given input source can also achieve the effect of adjusting the pulse width or period of the first square wave signal.

[0038] Specifically, the capacitor can be capacitor C42, and the first variable resistor assembly can include an adjustable resistor W1 and a resistor R62. The adjustable end of the adjustable resistor W1 is connected to the first given port 220, and the fixed end of the adjustable resistor W1 is connected to one end of the resistor R62. The other end of the resistor R62 is connected to one end of the capacitor C42 and the contact end of the first contact level converter 120, respectively. The other end of the capacitor C42 is grounded. Adjusting the resistance value of the adjustable resistor W1 or changing the resistance value of the resistor R62 based on the circuit architecture of this design can also achieve the function of adjusting the pulse width or period of the first square wave signal.

[0039] This structure is simple and provides users with multiple ways to change the output PWM signal, making it more flexible compared to previous integrated chip control.

[0040] In some embodiments of the present invention, the triggering unit 130 includes a second contact level converter 131, the output terminal of the first contact level converter 120 is connected to the contact terminal of the second contact level converter 131, the second contact level converter 131 can change the level of the output signal of the output terminal of the second contact level converter 131 according to the input signal received by the contact terminal of the second contact level converter 131, and the output terminal of the second contact level converter 131 is connected to the controlled terminal of the first energy dissipation unit 110.

[0041] Both the first contact level converter 120 and the second contact level converter 131 can be Schmitt triggers. Specifically, the trigger unit 130 can also include a resistor R74. One end of the resistor R74 is connected to the output terminal of the first contact level converter 120, and the other end of the resistor R74 is connected to the contact terminal of the second contact level converter 131. When the output terminal of the first contact level converter 120 outputs a high level, and the input signal voltage received by the contact terminal of the second contact level converter 131 increases, the output terminal of the first contact level converter 120 outputs a low level (i.e., point B), and the first energy dissipation unit 110 is disconnected. The first given input source charges the capacitor C42 through the first given port 220. When the output terminal of the first contact level converter 120 outputs a low level, the output terminal of the first contact level converter 120 outputs a high level (i.e., point B), and the first energy dissipation unit 110 is closed. At this time, the capacitor C42 discharges.

[0042] Specifically, the first energy dissipation unit 110 can be a switching transistor Q6, which can be a transistor, MOSFET, IGBT, etc.

[0043] In some embodiments of the present invention, such as Figure 2 , 3 As shown in Figure 7, the second modulation unit 400 includes a second energy storage unit 410, a second given port 420, and a third given port 430. The second given port 420 is used to connect to a second given input source, and the third given port 430 is used to connect to a third given input source. The second waveform modulation module 300 includes a comparison unit 310 and a second energy dissipation unit 320. The second energy storage unit 410 is connected to the second given port 420, the first input terminal of the comparison unit 310, and the input terminal of the second energy dissipation unit 320, respectively. The second input terminal of the comparison unit 310 is connected to the third given port 430. The comparison unit 310 can compare the input signals received by the first input terminal and the second input terminal of the comparison unit 310 to change the level (i.e., point D) of the output signal of the output terminal of the comparison unit 310. The output terminal of the comparison unit 310 is connected to the PWM modulation module 500. The controlled terminal of the second energy dissipation unit 320 is connected to the first waveform modulation module 100 to control the second energy dissipation unit 320 to dissipate the energy of the second energy storage unit 410.

[0044] The third given input source provides a reference voltage to the second input terminal of the comparison unit 310 through the third given port 430. The second given input source charges the second energy dissipation unit 320 through the second given terminal. When the stored energy of the second energy storage unit 410 increases to a certain level (i.e., point E), the voltage of the first input terminal of the comparison unit 310 is higher than the voltage of the second input terminal of the comparison unit 310, and the output terminal of the comparison unit 310 outputs a low level.

[0045] The controlled terminal of the second energy dissipation unit 320 is controlled by the first waveform modulation module 100. Specifically, the controlled terminal of the second energy dissipation unit 320 is connected to the output terminal of the second contact level converter 131 (i.e., point B). When the first energy dissipation unit 110 is turned on, the second energy dissipation unit 320 will also be turned on. When the second energy dissipation unit 320 is turned on, the second energy storage unit 410 discharges, which lowers the voltage of the first input terminal of the comparison unit 310, thereby causing the output terminal of the comparison unit 310 (i.e., point D) to output a high level.

[0046] In some embodiments of the present invention, the second waveform modulation module 300 further includes a third contact level converter 330. The contact terminal of the third contact level converter 330 is connected to the output terminal of the comparison unit 310. The third contact level converter 330 can change the level of the output signal of the output terminal of the third contact level converter 330 to form a second square wave signal according to the input signal received by the contact terminal of the third contact level converter 330. The output terminal of the third contact level converter 330 is connected to the PWM modulation module 500.

[0047] The third contact level converter 330 can flip the level output by the output terminal of the comparison unit 310, thereby forming a second square wave signal.

[0048] Therefore, the first waveform modulation module 100 modulates the first square wave signal (i.e., the output waveform at point A), and the second waveform modulation module 300 modulates the second square wave signal (i.e., the output waveform at point F). Since the controlled terminal of the second energy dissipation unit 320 is connected to the output terminal of the second contact level converter 131, the second square wave signal and the first square wave signal have the same period, specifically as follows: Figure 7 As shown, the period is T. During period T, the first square wave signal and the second square wave signal are triggered simultaneously. The first square wave signal changes from low level to high level, and the second square wave signal changes from high level to low level. Then, according to the specific settings of the second energy storage unit 410, the second given port 420, and the third given port 430, as the stored energy of the second energy storage unit 410 increases to a certain level (i.e., point E), the voltage at the first input terminal of the comparison unit 310 is higher than the voltage at the second input terminal of the comparison unit 310. The second square wave signal flips from low level to high level. Finally, at the end of the same period, the second square wave signal and the first square wave signal are triggered synchronously again, and the second square wave signal flips from high level to low level.

[0049] Specifically, the third contact level converter 330 can be a Schmitt trigger, the comparison unit 310 can be selected from a conventional comparator, and the second energy dissipation unit 320 can be a switching transistor Q1, which can be a transistor, MOSFET, IGBT, etc.

[0050] The specific settings of the second energy storage unit 410, the second given port 420, and the third given port 430 can adjust the interval between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal. Specifically, it is the difference between the time point at the beginning of period T when the first square wave signal changes from low level to high level and the time point in the middle of period T when the second square wave signal changes from low level to high level.

[0051] In some embodiments of the present invention, the user can adjust the output voltage of the third given input source according to the actual situation, thereby adjusting the magnitude of the reference voltage provided to the first input terminal of the comparison unit 310 through the third given port 430. When the reference voltage is larger, the energy storage capacity of the second energy storage unit 410 increases to the point that the voltage of the first input terminal of the comparison unit 310 is higher than the voltage of the second input terminal of the comparison unit 310 under the same charging efficiency, which prolongs the time interval between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal.

[0052] Alternatively, the user can change the output voltage of the second given input source, which charges the second energy storage unit 410 through the second given port 420. When the output voltage of the second given input source is larger, and the specifications of the second energy storage unit 410 remain unchanged, the energy storage capacity of the second energy storage unit 410 increases to a level that shortens the time when the voltage at the first input terminal of the comparison unit 310 is higher than the voltage at the second input terminal of the comparison unit 310, thereby shortening the interval between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal.

[0053] In some embodiments of the present invention, the second energy storage unit 410 includes a capacitor C25 and a resistor R45. One end of the resistor R45 is connected to the second given port 420, and one end of the capacitor C25 is connected to the other end of the resistor R45, the first input terminal of the comparison unit 310 and the input terminal of the second energy dissipation unit 320, respectively. The other end of the capacitor C25 is grounded.

[0054] Based on the circuit architecture of this design, capacitor C25 and resistor R45 with different specifications can also be replaced, which can also adjust the interval between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal.

[0055] This design has a simple structure and provides users with multiple ways to change the output PWM signal, making it more flexible than previous integrated chip control.

[0056] In some embodiments of the present invention, such as Figure 5 , 6As shown, it also includes a current detection module 710 and a switch module 720. The current detection module 710 is used to sample the output current of the output terminal of the inverter module 800 of the welding machine. The input terminal of the switch module 720 is connected to the second input terminal and the third given port 430 of the comparison unit 310, respectively. The output terminal of the switch module 720 is grounded. The current detection module 710 is connected to the switch module 720 to control the switching module 720 to turn on and off.

[0057] Specifically, the current detection module 710 may include a resistor voltage divider sampling circuit composed of sampling resistors R92 and R83 to sample the primary current of the main transformer T1. When an overcurrent occurs, it can control the switching module 720 to conduct, thereby pulling down the voltage at the second input terminal of the comparison unit 310, raising the level at point F, and thus causing the levels of QC and QD to flip. Based on the H-bridge structure of the inverter module 800, it can control the output to decrease, thereby limiting the current. Specifically, as shown... Figure 5 As shown, the current detection module 710 may also include components such as a comparator and a Schmitt trigger, and the switching module 720 may include a switching transistor Q2, specifically, the switching transistor Q2 may be a transistor, a MOSFET, an IGBT, etc.

[0058] According to a second aspect of the present invention, the welding machine includes an adjustable PWM signal generating circuit disclosed in any of the above embodiments.

[0059] The welding machine of this invention utilizes an adjustable PWM signal generation circuit to control the operation of the inverter module 800 of the welding machine, and can modulate the PWM signal used to control the inverter module 800. This design utilizes a modular combination structure that is easy to adjust according to actual conditions, making it flexible to use and reducing construction costs.

[0060] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An adjustable PWM signal generation circuit, characterized in that, include: The first waveform modulation module is capable of outputting a first square wave signal. The first waveform modulation module is provided with a first modulation section, which can modulate a first property of the first square wave signal, wherein the first property includes at least one of pulse width and period. The second waveform modulation module is capable of outputting a second square wave signal. The second waveform modulation module is connected to the first waveform modulation module so that the second square wave signal and the first square wave signal have the same period. The second waveform modulation module is provided with a second modulation section, which can modulate a second property of the second square wave signal. The second property includes the interval time between the edge triggering of the second square wave signal and the edge triggering of the first square wave signal. A PWM modulation module is connected to the first waveform modulation module and the second waveform modulation module respectively to modulate multiple PWM signals according to the first property and the second property; The second modulation unit includes a second energy storage unit, a second given port, and a third given port. The second given port is used to connect to a second given input source, and the third given port is used to connect to a third given input source. The second waveform modulation module includes a comparison unit and a second energy dissipation unit. The second energy storage unit is connected to the second given port, the first input terminal of the comparison unit, and the input terminal of the second energy dissipation unit. The second input terminal of the comparison unit is connected to the third given port. The comparison unit can compare the input signals received by the first and second input terminals of the comparison unit to change the level of the output signal of the comparison unit. The output terminal of the comparison unit is connected to the PWM modulation module. The controlled terminal of the second energy dissipation unit is connected to the first waveform modulation module to control the second energy dissipation unit to dissipate the energy of the second energy storage unit. The adjustable PWM signal generation circuit also includes a current detection module and a switching module. The current detection module is used to sample the output current of the inverter module of the welding machine. The input terminal of the switching module is connected to the second input terminal of the comparison unit and the third given port, respectively. The output terminal of the switching module is grounded. The current detection module is connected to the switching module to control the switching module to turn on and off.

2. The adjustable PWM signal generating circuit according to claim 1, characterized in that: The first modulation unit includes a first energy storage unit and a first given port. The first waveform modulation module further includes a first energy dissipation unit, a trigger unit, and a first contact level converter. The first given port is used to connect to a first given input source. The first energy storage unit is connected to the first given port, the input terminal of the first energy dissipation unit, and the contact terminal of the first contact level converter. The first contact level converter can change the level of the output signal of the first contact level converter to form a first square wave signal according to the input signal received by the contact terminal of the first contact level converter. The output terminal of the first contact level converter is connected to the input terminal of the trigger unit and the PWM modulation module. The output terminal of the trigger unit is connected to the controlled terminal of the first energy dissipation unit to control the first energy dissipation unit to dissipate the energy of the first energy storage unit.

3. The adjustable PWM signal generating circuit according to claim 2, characterized in that: The first energy storage unit includes a first variable resistor assembly and a capacitor. One end of the first variable resistor assembly is connected to a first given port. One end of the capacitor is connected to the other end of the first variable resistor assembly, the input terminal of the first energy dissipation unit, and the contact terminal of the first contact level converter. The other end of the capacitor is grounded.

4. The adjustable PWM signal generating circuit according to claim 2, characterized in that: The triggering unit includes a second contact level converter. The output terminal of the first contact level converter is connected to the contact terminal of the second contact level converter. The second contact level converter can change the level of the output signal of the second contact level converter according to the input signal received by the contact terminal of the second contact level converter. The output terminal of the second contact level converter is connected to the controlled terminal of the first energy dissipation unit.

5. The adjustable PWM signal generating circuit according to claim 1, characterized in that: The second waveform modulation module further includes a third contact level converter. The contact terminal of the third contact level converter is connected to the output terminal of the comparison unit. The third contact level converter can change the level of the output signal of the third contact level converter to form a second square wave signal according to the input signal received by the contact terminal of the third contact level converter. The output terminal of the third contact level converter is connected to the PWM modulation module.

6. The adjustable PWM signal generating circuit according to claim 1, characterized in that: The PWM modulation module includes a first PWM modulation unit and a second PWM modulation unit. Both the first PWM modulation unit and the second PWM modulation unit include a trigger terminal, a first output terminal, and a second output terminal. The first waveform modulation module is connected to the trigger terminal of the first PWM modulation unit. The first output terminal of the first PWM modulation unit outputs a first PWM signal, and the second output terminal of the second PWM modulation unit outputs a second PWM signal. The first PWM signal and the second PWM signal are complementary, and the first PWM modulation unit controls the first PWM signal and the second PWM signal to flip according to the first property. The second waveform modulation module is connected to the trigger terminal of the second PWM modulation unit. The first output terminal of the second PWM modulation unit outputs a third PWM signal and the second output terminal of the second PWM modulation unit outputs a fourth PWM signal. The third PWM signal and the fourth PWM signal are complementary, and the second PWM modulation unit controls the third PWM signal and the fourth PWM signal to flip according to the second property.

7. The adjustable PWM signal generating circuit according to claim 1, characterized in that: It also includes an isolation module, the output of the PWM modulation module is connected to the input of the isolation module, and the output of the isolation module is used to connect to the controlled end of the inverter module of the welding machine.

8. An electric welding machine, characterized in that, Includes an adjustable PWM signal generating circuit as described in any one of claims 1-7.

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