A multi-voltage inverter welding machine control circuit power supply method and inverter welding machine

Abstract

The application discloses a kind of multi-voltage inverter welding machine control circuit power supply method and inverter welding machine, it is related to welding technical field, design successively connected power supply circuit, drive circuit, inverter circuit and power transformer, comprising: using power supply circuit, high-voltage alternating current is stepped down into low-voltage alternating current, low-voltage alternating current is rectified and filtered, BUCK voltage reduction and BUCK-BOOST conversion in turn, generate stable positive and negative power supply voltage, power supply for drive circuit;Using drive circuit, the operation of inverter circuit is driven using the PWM control strategy based on phase-shifted driving, inverter circuit converts stable DC in the main circuit of multi-voltage inverter welding machine into stable AC according to PWM control strategy;Converted stable AC is connected to power transformer primary side, and the control circuit of multi-voltage inverter welding machine and machine auxiliary are powered by power transformer secondary side.The application realizes the stable power supply for multi-voltage inverter welding machine by only adding a kind of power supply circuit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of welding, and particularly relates to a multi-voltage inverter welding machine control circuit power supply method and an inverter welding machine. BACKGROUND

[0002] The principle of the inverter welding machine is to convert the power frequency alternating current into direct current, and then convert it into high-frequency alternating current through the inverter circuit, and then supply it for welding after rectification. Due to the characteristics of high efficiency and low cost, the application scene and range of the inverter welding machine are becoming more and more extensive. Considering that the power supply voltage is not uniform between different regions, different power supply voltages are considered, and the inverter welding machine needs to be designed separately. In order to avoid this diversified design, the inverter welding machine is currently designed to be able to adapt to multiple voltage inputs at the same time, that is, a multi-voltage inverter welding machine is proposed, which allows input of multiple voltage levels, for example, it can allow alternating current 220V-575V input. Through this design, the inverter welding machine can be applied to different power supply voltage occasions, facilitating popularization and use.

[0003] The circuit composition of the inverter welding machine is generally divided into a control circuit and a power circuit, wherein the control circuit can perform the functions of feedback and adjusting the power circuit, and the power circuit is used to output the current and voltage for welding. Under normal circumstances, the inverter welding machine is powered by a control circuit after the voltage is reduced by a power transformer, wherein the primary and secondary voltages of the power transformer are in proportional relationship, and the proportional coefficient is determined by the number of turns of the winding. The change of the primary voltage will cause the corresponding change of the secondary voltage. Since the multi-voltage inverter welding machine can input alternating current with a wide range of voltages, the power supply of the control circuit is also a wide range of voltages, which needs to be stabilized before the control circuit is powered. This can ensure the stability of the subsequent operation.

[0004] In the prior art, switching power supply or magnetic saturation transformer stabilization technology is usually used, but these technologies have certain problems:

[0005] (1) The switching power supply or other DC power supply form allowing wide range input is used to stabilize the wide range of AC power. However, in the design of the switching power supply, on the one hand, the reliability of the high-voltage input switching power supply is low, and the loss of high-voltage devices used in the high-voltage switching power supply circuit is large, which makes it difficult to design a high-power high-voltage switching power supply. On the other hand, the design of the switching power supply allowing more than 2 times wide range input is complex and has high cost, especially in the case of more than 2 times wide range input high voltage. In addition, various components in the inverter welding machine need to be powered by AC power, such as the wire feeder, the auxiliary heating of the gas meter, the AC cooling fan, and various electric tools that may be used in welding. Using switching power supply and other DC power supply forms for power supply cannot meet the actual application requirements.

[0006] (2) Considering that magnetic saturation transformers are a type of power transformer, they allow multiple input voltages. However, the allowable input voltage range of magnetic saturation transformers is relatively narrow. They are generally designed to allow voltage fluctuations of ±15%. Voltage fluctuations exceeding ±15% will lead to design difficulties, and designs with voltage fluctuations exceeding ±30% are basically difficult to achieve. Therefore, it is not practical to use magnetic saturation transformers to solve the power supply problem of control circuits. Moreover, high-power magnetic saturation transformers are very large, which places high demands on the structural design of inverter welding machines. Magnetic saturation transformers also have many disadvantages, such as output voltage distortion which is not conducive to the design of subsequent control circuit power supplies, high losses, electromagnetic interference during operation, and the need to use them with resonant capacitors, which leads to higher costs.

[0007] (3) The output stability of the power transformer can also be achieved by switching transformer taps. However, multiple switches and control circuits are required when multiple voltage inputs are used. Whether the switch is switched manually or the switch is automatically switched with a matching control circuit, there is a risk of switching errors or mis-switching. Moreover, the switching process is usually energized, which may cause the switch contacts to arc, thus affecting the reliability of the switch. Therefore, this method has the problem of low power supply reliability. Summary of the Invention

[0008] To address the shortcomings of the prior art, this invention provides a power supply method for the control circuit of a multi-voltage inverter welding machine and an inverter welding machine. Addressing the difficulty in designing the power supply for the inverter welding machine control circuit, this invention considers the stable voltage obtained by converting different input voltages in a multi-voltage inverter welding machine. A method for powering the control circuit using this stable voltage is developed. Specifically, by designing an inverter circuit and a corresponding phase-shifting drive strategy, this stable voltage is converted into stable AC power. This AC power, after being converted by a power transformer, can provide AC power to the welding machine control circuit and other components, auxiliary tools, etc., thereby achieving a simpler design and smaller size for wide-range AC voltage regulation and AC power supply.

[0009] In a first aspect, the present invention provides a power supply method for a multi-voltage inverter welding machine control circuit.

[0010] A power supply method for a multi-voltage inverter welding machine control circuit, comprising a power supply circuit, a drive circuit, an inverter circuit, and a power transformer connected in sequence, including:

[0011] The high-voltage AC power is stepped down to low-voltage AC power using a power supply circuit. The low-voltage AC power is then rectified, filtered, stepped down by BUCK, and converted by BUCK-BOOST to generate a stable positive and negative power supply voltage to power the drive circuit.

[0012] The driving circuit is used to drive the operation of the inverter circuit by using a PWM control strategy based on phase shift driving, and the inverter circuit converts the stable direct current in the main circuit of the multi-voltage inverter welding machine into stable alternating current according to the PWM control strategy.

[0013] The converted stable alternating current is connected to the primary side of the power transformer, and the control circuit and auxiliary equipment of the multi-voltage inverter welding machine are powered by the secondary side of the power transformer.

[0014] In the second aspect, the application further provides an inverter welding machine, which is powered by the multi-voltage inverter welding machine control circuit power supply method in the first aspect.

[0015] The above one or more technical solutions have the following beneficial effects:

[0016] 1. The application provides a multi-voltage inverter welding machine control circuit power supply method and an inverter welding machine. In order to solve the problem of difficult design of the power supply of the inverter welding machine control circuit, in the multi-voltage inverter welding machine, in order to achieve optimal welding performance, a boost or buck mode (or a boost-buck mode) is usually used to convert different input voltages into a stable voltage. Therefore, the application uses the stable voltage to design a power supply method for the control circuit, converts the stable voltage into stable alternating current by designing an inverter circuit and a corresponding phase shift driving strategy, and the alternating current can provide alternating current power supply for the welding machine control circuit and other components and auxiliary equipment after being converted by a power transformer. In this way, a wide range of AC voltage stabilization and AC power supply with simpler design and smaller size are achieved, the disadvantages of using high-voltage wide-range switching power supply, magnetic saturation transformer or switching transformer tap power supply mode in the multi-voltage welding machine are avoided, the power supply reliability and stability are effectively improved, the interference is reduced, and optimal welding performance is achieved.

[0017] 2. The application designs a power supply circuit and a power transformer combination to supply power. The power supply circuit converts the stable voltage converted based on different input voltages into alternating current (such as AC square wave or sine wave, etc.), and the alternating current provides alternating current power supply for the welding machine control circuit and other components and auxiliary equipment after being converted by the power transformer, solving the problem of alternating current power supply required by related circuits and components. The application can meet the power supply application of the multi-voltage welding machine, and the output is alternating current, which can meet the application of other tools requiring alternating current power supply. Compared with the single-voltage power supply welding machine, only one power supply circuit is added, the design is simple, the size is small, and the use is convenient.

[0018] 3、In the application, the power supply circuit design and power transformer are combined into a power supply scheme, by adjusting the number of turns of the power transformer design, the power transformer can be designed to have the same voltage output as the single voltage power supply welding machine transformer, so that the control circuit and the components that need AC power in the multi-voltage welding machine can directly use the design scheme of the single voltage welding machine, and no additional multi-voltage welding machine design is needed, which can further simplify the design scheme. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings accompanying the specification of the application form a part of the application and serve to further understand the application. The illustrative embodiments of the application and their description serve to explain the application without forming an improper limitation of the application.

[0020] Figure 1 The connection frame schematic diagram of the power supply circuit provided in the multi-voltage inverter welding machine control circuit power supply method of the embodiment of the application;

[0021] Figure 2 The connection frame diagram of the power supply circuit in the embodiment of the application;

[0022] Figure 3 The circuit diagram of the power supply circuit in the embodiment of the application;

[0023] Figure 4 The circuit diagram of the inverter circuit and its driving circuit in the embodiment of the application;

[0024] Figure 5 The schematic diagram of the output square wave AC power generation distortion when the traditional full-bridge drive is adopted;

[0025] Figure 6 The driving waveform schematic diagram generated by the phase shift driving strategy in the embodiment of the application;

[0026] Figure 7 The schematic diagram of a circuit for generating a driving signal in the embodiment of the application;

[0027] Figure 8 The schematic diagram of another circuit for generating a driving signal in the embodiment of the application;

[0028] Figure 9 The main circuit schematic diagram of the multi-voltage inverter welding machine in the embodiment of the application. DETAILED DESCRIPTION

[0029] It should be noted that the following detailed description is exemplary only and is intended to provide further description of the present application in order to provide further explanation of the exemplary embodiments according to the present application and is not intended to limit the exemplary embodiments according to the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Furthermore, it should be understood that the use of the term "including", as well as other like terms, in this specification is intended to mean "including, but not limited to" and not intended to limit the exemplary embodiments according to the present application.

[0030] In view of the difficulty in designing the power supply of the inverter welding machine control circuit, in order to obtain optimal welding performance, a boost or buck mode (or boost-buck mode) is usually used to convert different input AC voltages into stable DC voltages in a multi-voltage inverter welding machine. On this basis, the present application proposes a multi-voltage inverter welding machine control circuit power supply method. By designing a corresponding circuit (including a power supply circuit, a driving circuit, an inverter circuit, and a power supply transformer), the inverter circuit in the circuit is used to convert the stabilized DC voltage in the main circuit of the inverter welding machine into AC power. The frequency of the AC power is the power frequency, which is generally 50Hz or 60Hz, which is different from the high inverter frequency (several tens of kHz) of the inverter welding machine. Since the input DC power of the inverter circuit is a stable voltage, the AC power after inversion is also a stable voltage, thereby realizing the voltage stabilization of a wide range of AC power.

[0031] Embodiment one

[0032] The present embodiment provides a multi-voltage inverter welding machine control circuit power supply method, which designs a power supply circuit, a driving circuit, an inverter circuit, and a power supply transformer connected in sequence, as shown in Figure 1 , including:

[0033] The power supply circuit is used to step down the high-voltage AC power to low-voltage AC power. The low-voltage AC power is rectified, filtered, BUCK stepped down, and BUCK-BOOST converted in sequence to generate stable positive and negative power supply voltages to power the driving circuit.

[0034] The driving circuit is used to drive the operation of the inverter circuit by using a PWM control strategy based on phase-shifted driving. The inverter circuit converts the stable DC power in the main circuit of the multi-voltage inverter welding machine into stable AC power according to the PWM control strategy.

[0035] The converted stable AC power is connected to the primary side of the power supply transformer, and the secondary side of the power supply transformer supplies power to the control circuit and auxiliary equipment of the multi-voltage inverter welding machine.

[0036] Firstly, for the power supply circuit, the power supply circuit is used for reducing the input high-voltage alternating current to low-voltage alternating current, and the low-voltage alternating current is converted to direct current after rectification and filtering, and the direct current is converted to stable positive and negative power supply voltages after BUCK voltage reduction and BUCK-BOOST conversion, to supply power for the driving circuit of the inverter circuit. In the embodiment, the power supply circuit includes a voltage reduction circuit, a rectification circuit, a BUCK voltage reduction circuit, a PWM control circuit, a BUCK-BOOST conversion circuit, a pulse generation circuit, a positive power supply linear voltage stabilizer and a negative power supply linear voltage stabilizer, and the working principle is as follows:

[0037] (1) The input high-voltage alternating current is reduced to low-voltage alternating current by a transformer, which can better ensure the reliability of the power supply circuit and also make the circuit design simpler;

[0038] (2) The low-voltage alternating current is converted to smooth direct current after rectification and filtering;

[0039] (3) The direct current is reduced to a positive power supply voltage by the BUCK voltage reduction circuit;

[0040] (4) The positive power supply voltage is converted to a negative power supply voltage after polarity reversal and voltage conversion by the BUCK-BOOST conversion circuit. Preferably, in order to make the positive and negative power supplies more stable, a positive and negative power supply linear voltage stabilizer is added in the output loop.

[0041] In the embodiment, the specific circuit structure of the power supply circuit is shown in Figure 3 , wherein the positive power supply is generated by PWM control, the BUCK voltage reduction circuit includes a switching tube KF4, the PWM control circuit includes a current-mode PWM controller K3 (3842), the pulse output pin (i.e. OUTP pin) of the PWM controller K3 is connected to the switching tube KF4, and the switching tube KF4 is controlled to turn on and turn off by the generated pulse to perform voltage conversion. Further, the voltage conversion principle is that a smooth direct current is input to the input end of the switching tube KF4, and since the KF4 is in a switching state, the output end of the KF4 is a pulsed direct current, and the effective value of the output end is smaller than that of the input end. The effective value of the output end can be calculated by the product of the input end voltage and the KF4 conduction duty ratio.

[0042] The above-mentioned positive power supply linear voltage stabilizer includes a linear voltage stabilizer K4, and the output of the BUCK voltage reduction circuit is input to the linear voltage stabilizer K4 for voltage stabilization to generate a positive power supply voltage.

[0043] Further, the source of the switch tube KF4 is connected with the current detection resistor R22, the current signal detected by the current detection resistor R22 is input to the ISE pin of the PWM controller K3, the ISE pin of the PWM controller K3 is connected with the current slope compensation circuit composed of the resistor R23 and the diode KF3, so that the feedback current in the full range can be detected, and the feedback current is the current flowing through the switch tube KF4, which has two functions, one is that the diode K3 is a current type PWM controller, and the current needs to be introduced as the input of the PWM control comparator, so that the PWM control is more stable; the other is that the overcurrent protection of the switch tube KF4 and other components in the loop can be realized by detecting the current, and when the current exceeds the limit of the components, the protection measures are started.

[0044] Further, the voltage feedback circuit is composed of the voltage regulator K7, the optocoupler KF6 and the peripheral circuit thereof, in the embodiment, the K7 is a voltage regulator, and the voltage at the REF pin of the K7 is stabilized at 2.5V; the voltage feedback circuit is connected to the COMP pin of the PWM controller K3, when the voltage at the REF pin of the voltage regulator K7 fluctuates, the current flowing through the K7 changes, and then the current in the light emitting diode in the optocoupler KF6 changes, and the current in the transistor in the KF6 after the transmission through the optocoupler changes, so that the voltage at the COMP pin end of the voltage comparator COMP of the PWM controller K3 changes, so as to adjust the PWM.

[0045] In the above design, the COMP pin of the K3 is used in the voltage feedback circuit, and the internal voltage error amplifier is skipped, so that the feedback is more timely. Specifically, there is a comparator unit in the PWM controller K3, the comparator has two inputs and one output, one of the inputs is the VFB pin, and the other input is the internal reference voltage source, and the output of the comparator unit is connected with the COMP pin. Under normal circumstances, the voltage feedback signal is processed and connected to the VFB pin, so that the voltage feedback signal (i.e. +VCC) and the voltage reference source in the K3 are compared, the comparator outputs different voltages, and then the output state of the OUTP pin is affected, and then the turn-on and turn-off time of the KF4 switch tube is adjusted. Considering that in this case the voltage feedback needs to pass through the voltage comparator in the device before affecting the output, there is a certain delay, therefore, in the embodiment, the voltage feedback signal is directly processed and connected to the COMP pin (i.e. the output end of the voltage comparator in the K3), which is equivalent to not using the voltage comparator, so that the delay can be reduced.

[0046] Furthermore, the switching transistors in the BUCK buck circuit are driven by floating ground and require a separate power supply. In this embodiment, a capacitor bootstrap circuit is designed as an isolated driving circuit. Since the driving reference GND of the switching transistor KF4 in the BUCK buck circuit is not the same as the reference GND of the control circuit (i.e., the K3 part of the PWM controller circuit), when the driving circuit is not isolated, the reference grounds of the two parts of the circuit are different, which will lead to problems such as overheating. By designing an isolated driving circuit, the reliability of the circuit can be guaranteed. In this design, the drain of the switching transistor KF4 is connected to a bootstrap capacitor circuit. This bootstrap capacitor circuit includes a diode RB3, a voltage regulator RC5, a bootstrap capacitor CE5, and a capacitor C13. The key components are RB3 and CE5. The reverse voltage of diode RB3 is greater than the DC voltage at which the switching transistor KF4 is turned on and off. This prevents the high voltage of the switching transistor KF4 from backflowing into the +V terminal, causing voltage fluctuations at the +V terminal. Simultaneously, RB3 needs to have sufficient current carrying capacity to drive the PWM controller and the switching transistor. In this embodiment, a fast recovery diode with low leakage current is selected. The bootstrap capacitor CE5 provides a charge no less than that required for the gate charge of the switching transistor KF4 to turn on and maintains its voltage during the switching transistor's conduction period. This design achieves isolated drive, eliminating the need for an additional isolation power supply and reducing costs.

[0047] Since the input and output voltages of the negative power supply circuit are stable and have a very small adjustment range, the negative power supply BUCK-BOOST circuit uses a fixed pulse width driven switching transistor KF5 in its design. The pulse generation circuit includes a multivibrator composed of a 555 timer K6 and its peripheral circuits. The multivibrator generates a fixed pulse width pulse signal and inputs this pulse signal to the switching transistor KF5. The switching transistor KF5 is turned on and off according to the pulse signal, thereby performing polarity reversal and voltage conversion. The output of the switching transistor KF5 is regulated and then input to the linear regulator K5 to generate a more stable negative power supply voltage.

[0048] Secondly, such as Figure 4 The inverter circuit and its drive circuit shown are a full-bridge inverter circuit. The output of the full-bridge inverter circuit is connected to the power transformer. However, due to the leakage inductance of the primary winding of the power transformer and the influence of the parasitic parameters of the switching transistors, when using a traditional full-bridge drive, LC resonance will occur after the IGBT is turned off, causing distortion of the output square wave AC current. Figure 5 As shown. Therefore, this embodiment proposes a phase-shifting driving strategy, and the driving waveform generated by this strategy is as follows. Figure 6 As shown, specifically, the full-bridge inverter includes four switching transistors Q1 to Q4. Switches Q1 and Q2 form the leading arm, and switches Q3 and Q4 form the lagging arm. The drive circuit includes a circuit for generating a drive signal, which is generated based on a phase-shifting drive strategy. This phase-shifting drive strategy is as follows:

[0049] The leading bridge arm opens in advance and turns off in advance; the lagging bridge arm opens in a lagging manner and turns off in a lagging manner.

[0050] When the upper bridge arm turns off, the diagonally opposite switch tube does not turn off, and the lower bridge arm is turned on after a small dead time is set, so that the parasitic capacitance of the upper and lower bridge arm and the primary leakage inductance of the power transformer do not resonate in the dead time. Further, the principle that it does not resonate is that when LC resonates, a kind of sinusoidal oscillation is generated, and the oscillation period can be simply described as T=2πLC. When the designed dead time is much smaller than T, the oscillation just enters another working state of the circuit, and at this time the oscillation does not continue. The small dead time is set to be less than 500uS, and at this time the resonance can be effectively avoided.

[0051] In this embodiment, the driving signal generated by the phase shift driving strategy is as shown in Figure 6 The driving circuit for generating the phase shift driving strategy is as shown in Figure 7 The UCC3895 is a dedicated phase shift PWM controller, and the working process is that the given voltage signal and the internal reference source are compared, an adjustable pulse voltage is output, and the pulse voltage is output through four OUT pins to drive the four switch tubes in the full-bridge inverter. In addition, the frequency of the pulse voltage can be adjusted through the clock oscillation circuit.

[0052] As another embodiment, the microprocessor (MCU), DSP and the like as shown in Figure 8 can be used to generate the phase shift driving strategy.

[0053] Through the above design, the full-bridge inverter circuit is driven by the driving signal to output a square wave alternating current, and the effective value of the square wave alternating current can be adjusted by adjusting the duty cycle.

[0054] Based on the above design, the principle diagram of the main circuit of the multi-voltage inverter welding machine proposed in this embodiment is as shown in Figure 9 The voltage stabilizing circuit can be a BOOST circuit, a BUCK circuit or a BUCK-BOOST circuit. As long as the inverter welding machine can generate stable direct current when multiple voltages are input, the above-described circuit can be used to realize stable power supply.

[0055] Embodiment two

[0056] The embodiment also provides an inverter welding machine, which is powered by the power supply method suitable for the multi-voltage inverter welding machine proposed in embodiment one.

[0057] The steps and methods involved in the above embodiment two correspond to embodiment one, and the specific implementation can be referred to the related description part of embodiment one, which will not be described in detail here.

[0058] Those skilled in the art should understand that the modules or steps of the present application described above can be realized by a general computer device, or alternatively, they can be realized by program codes executable by a computing device, so that they can be stored in a storage device and executed by a computing device, or they can be respectively manufactured into individual integrated circuit modules, or a plurality of modules or steps among them can be manufactured into a single integrated circuit module. The present application is not limited to any specific combination of hardware and software.

[0059] The above description is only the preferred embodiments of the present application, and the specific embodiments of the present application are described in conjunction with the drawings, but are not intended to limit the scope of protection of the present application. Those skilled in the art should understand that various modifications or variations made on the basis of the technical solutions of the present application without creative labor are still within the scope of protection of the present application.

Claims

1. A method for powering a multi-voltage inverter welder control circuit, comprising: The power supply circuit, the driving circuit, the inverter circuit and the power transformer are connected in sequence, comprising: The high-voltage alternating current is converted into low-voltage alternating current by the power supply circuit, and the low-voltage alternating current is rectified, filtered, BUCK voltage-reduced and BUCK-BOOST converted in sequence to generate stable positive and negative power supply voltages for the driving circuit; The driving circuit is used to drive the operation of the inverter circuit by adopting a PWM control strategy based on phase shift driving, and the inverter circuit converts the stable direct current in the main circuit of the multi-voltage inverter welding machine into stable alternating current according to the PWM control strategy; The converted stable alternating current is connected to the primary side of the power transformer, and the secondary side of the power transformer supplies power to the control circuit and auxiliary equipment of the multi-voltage inverter welding machine; The inverter circuit adopts a full-bridge inverter circuit, wherein the full-bridge inverter includes four switching tubes Q1-Q4, the switching tube Q1 and the switching tube Q2 form a leading bridge arm, and the switching tube Q3 and the switching tube Q4 form a lagging bridge arm; the PWM control strategy based on phase shift driving is as follows: The leading bridge arm is opened in advance and turned off in advance; the lagging bridge arm is opened with a delay and turned off with a delay; After the upper bridge arm is turned off, the switching tube on the diagonal is not turned off, and the lower bridge arm is opened after a small dead time is set; The full-bridge inverter circuit converts the stable direct current in the main circuit of the multi-voltage inverter welding machine into stable alternating current under the PWM control strategy based on phase shift driving, and outputs undistorted square wave alternating current; wherein the effective value of the square wave alternating current is adjusted by adjusting the duty cycle.

2. A method of providing power to a multi-voltage inverter welder control circuit as defined in claim 1, wherein, The power supply circuit includes a voltage-reduction circuit, a rectifier circuit, a BUCK voltage-reduction circuit, a PWM control circuit, a BUCK-BOOST conversion circuit, a pulse generation circuit, a positive power supply linear voltage stabilizer and a negative power supply linear voltage stabilizer; The high-voltage alternating current is input into the power supply circuit, is reduced in voltage by the voltage-reduction circuit to become low-voltage alternating current, and is converted into direct current after rectification and filtering; The direct current is voltage-reduced to become a positive power supply voltage by the BUCK voltage-reduction circuit controlled by the PWM control circuit; The positive power supply voltage is polarity-inverted and voltage-converted by the BUCK-BOOST conversion circuit to generate a negative power supply voltage.

3. A method of providing power to a multi-voltage inverter welder control circuit as defined in claim 2, wherein, The BUCK voltage-reduction circuit includes a switching tube KF4, and the PWM control circuit includes a PWM controller K3, the pulse output pin of the PWM controller K3 is connected to the switching tube KF4, the conduction and turn-off time of the switching tube KF4 are controlled by the generated pulse, and voltage conversion is performed in this way; The positive power supply linear voltage stabilizer includes a linear voltage stabilizer K4, and the output of the BUCK voltage-reduction circuit is input into the linear voltage stabilizer K4 for voltage stabilization to generate a positive power supply voltage.

4. A method of providing power to a multi-voltage inverter welder control circuit as defined in claim 2, wherein, The BUCK-BOOST conversion circuit includes a fixed pulse width driven switching tube KF5, the pulse generation circuit includes a multivibrator composed of a 555 timer K6 and its peripheral circuit, the multivibrator generates a fixed pulse width pulse signal, and the generated pulse signal is input into the switching tube KF5, the conduction and turn-off time of the switching tube KF5 are controlled according to the pulse signal, and polarity inversion and voltage conversion are performed in this way; The negative power linear voltage stabilizing circuit comprises a linear voltage stabilizer K5, and the output of the BUCK-BOOST conversion circuit is input to the linear voltage stabilizer K5 for voltage stabilization to generate a negative power voltage.

5. A method of providing power to a multi-voltage inverter welder control circuit as defined in claim 3, wherein, The COMP pin of the PWM controller K3 is connected to a voltage feedback circuit, and the voltage feedback circuit comprises a voltage stabilizer K7, a photoelectric coupler KF6 and a peripheral circuit thereof; when the voltage of the REF pin of the voltage stabilizer K7 fluctuates, the current in the light-emitting diode of the photoelectric coupler KF6 changes, the current in the transistor of the photoelectric coupler KF6 changes after transmission, and the voltage at the COMP pin end of the voltage comparator of the PWM controller K3 changes, so as to perform PWM adjustment.

6. A method of providing power to a multi-voltage inverter welder control circuit as defined in claim 3 wherein, The drain of the switch tube KF4 is connected to a capacitor bootstrap circuit, and the capacitor bootstrap circuit comprises a diode RB3, a voltage stabilizer RC5, a bootstrap capacitor CE5 and a capacitor C13, wherein the reverse voltage of the diode RB3 is greater than the direct current voltage when the switch tube KF4 is turned on and turned off, and the bootstrap capacitor CE5 is used to provide the charge required for the gate charge of the switch tube KF4 to be turned on.

7. A method for supplying power to a multi-voltage inverter welder control circuit as defined in claim 1 wherein, The small dead zone time is set to be less than 500uS.

8. An inverter welder characterized by, The power supply method is used for the power supply of the multi-voltage inverter welder control circuit according to any one of claims 1-7.

Images