Intelligent frequency conversion circuit applied to welding equipment

Abstract

The application discloses an intelligent frequency conversion circuit applied to a welding device, and contains a PWM control chip and a frequency control circuit; the frequency control circuit is connected with the PWM control chip and is used for controlling the frequency of the PWM control chip. The frequency control circuit contains a filter circuit, a comparator, a voltage dividing circuit, a fourteenth resistor, a fifteenth resistor, an eighth capacitor, a fourth resistor, a fifth resistor and a MOS tube. The application proposes an intelligent frequency conversion scheme, so that the machine can change the frequency according to itself, and the effect is improved.

Description

Technical Field

[0001] This invention relates to the field of welding machine technology, and in particular to an intelligent frequency conversion circuit for welding equipment. Background Technology

[0002] Currently, in the welding machine industry, because a welding machine needs to change its own inverter frequency to meet different current requirements, the traditional method is to manually control the frequency, which is very inconvenient. Summary of the Invention

[0003] According to an embodiment of the present invention, an intelligent frequency conversion circuit for welding equipment is provided, comprising: a PWM control chip and a frequency control circuit; The frequency control circuit is connected to the PWM control chip and is used to control the frequency of the PWM control chip.

[0004] Furthermore, the frequency control circuit includes: a filter circuit, a comparator, a voltage divider circuit, a fourteenth resistor, a fifteenth resistor, an eighth capacitor, a fourth resistor, a fifth resistor, and a MOSFET; The input terminal of the filter circuit is connected to the PWM control chip to receive the PWM output signal from the PWM control chip and convert the PWM output signal into DC voltage. The inverting input of the comparator is connected to the output of the filter circuit. The voltage divider circuit is connected to the non-inverting input of the PWM control chip and the comparator to provide a fixed reference voltage threshold for the comparator. One end of the fourteenth resistor is connected to the voltage divider circuit, and the other end of the fourteenth resistor is connected to the output of the comparator. One end of the fifteenth resistor and one end of the eighth capacitor are connected to the output of the comparator. The other end of the fifteenth resistor is connected to the VCC voltage, and the other end of the eighth capacitor is grounded. One end of the fourth resistor and one end of the fifth resistor are connected to pin 9 of the PWM control chip, the other end of the fifth resistor is connected to pin 3 of the PWM control chip, and the other end of the fourth resistor is connected to the drain of the MOSFET. The gate of the MOSFET is connected to the output of the comparator, and the source of the MOSFET is grounded.

[0005] Furthermore, the filter circuit includes: a tenth resistor, a sixth capacitor, an eleventh resistor, and a seventh capacitor; One end of the tenth resistor is connected to the PWM control chip, and the other end of the tenth resistor is connected to one end of the sixth capacitor and one end of the eleventh resistor. The other end of the sixth capacitor is grounded; The other end of the eleventh resistor is connected to the inverting input of the comparator and one end of the seventh capacitor; The other end of the seventh capacitor is grounded.

[0006] Furthermore, the voltage divider circuit includes: a twelfth resistor and a thirteenth resistor; One end of the twelfth resistor is connected to pin 2 of the PWM control chip, and the other end of the twelfth resistor is connected to one end of the thirteenth resistor and the non-inverting input of the comparator. One end of the thirteenth resistor is connected to one end of the fourteenth resistor, and the other end of the thirteenth resistor is grounded.

[0007] Furthermore, it also includes a current detection circuit, which is connected to the PWM control chip for current detection.

[0008] Furthermore, the current detection circuit includes: a transistor, a ninth capacitor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a current detection signal output interface; The collector of the transistor is connected to pin 2 of the PWM control chip, the base of the transistor is connected to pin 8 of the PWM control chip and one end of the sixth capacitor, and the emitter of the transistor is connected to one end of the sixth resistor. The other end of the ninth capacitor is grounded; The other end of the sixth resistor is connected to one end of the seventh resistor, one end of the eighth resistor, and pin 4 of the PWM control chip; The other end of the seventh resistor is connected to the current detection signal output interface; One end of the ninth resistor is connected between one end of the eighth resistor and pin 4 of the PWM control chip, while the other ends of the ninth resistor and the other end of the eighth resistor are grounded.

[0009] According to an embodiment of the present invention, an intelligent frequency conversion circuit for welding equipment is proposed, which enables the machine to change its frequency according to its own needs, thereby improving the efficiency.

[0010] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0011] Figure 1 This is a circuit diagram of an intelligent frequency conversion circuit applied to welding equipment according to an embodiment of the present invention. Detailed Implementation

[0012] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, further illustrating the present invention.

[0013] First, combine Figure 1 This invention describes an intelligent frequency conversion circuit for use in welding equipment, applicable to a wide range of welding equipment.

[0014] like Figure 1 As shown, an intelligent frequency conversion circuit for welding equipment according to an embodiment of the present invention includes a PWM control chip U1 and a frequency control circuit.

[0015] Specifically, such as Figure 1 As shown, the frequency control circuit is connected to the PWM control chip U1 and is used to control the frequency of the PWM control chip U1. The frequency control circuit includes: a filter circuit, a comparator U2B, a voltage divider circuit, a fourteenth resistor R14, a fifteenth resistor R15, an eighth capacitor C8, a fourth resistor R4, a fifth resistor R5, and a MOSFET T1; the input terminal of the filter circuit is connected to the PWM control chip U1 and is used to receive the PWM output signal of the PWM control chip U1 and convert the PWM output signal into a DC voltage; the inverting input terminal of the comparator U2B is connected to the output terminal of the filter circuit; the voltage divider circuit is connected to the non-inverting input terminal of the PWM control chip U1 and the comparator U2B and is used to provide a fixed reference voltage threshold for the comparator U2B; one end of the fourteenth resistor R14 is connected to... The voltage divider circuit is connected, with the other end of the fourteenth resistor R14 connected to the output of comparator U2B; one end of the fifteenth resistor R15 and one end of the eighth capacitor C8 are connected to the output of comparator U2B, the other end of the fifteenth resistor R15 is connected to VCC voltage, and the other end of the eighth capacitor C8 is grounded; one end of the fourth resistor R4 and one end of the fifth resistor R5 are connected to pin 9 of the PWM control chip U1, the other end of the fifth resistor R5 is connected to pin 3 of the PWM control chip U1, and the other end of the fourth resistor R4 is connected to the drain of MOSFET T1; the gate of MOSFET T1 is connected to the output of comparator U2B, and the source of MOSFET T1 is grounded. Among these, the fourteenth resistor R14 is a positive feedback resistor, introducing hysteresis to prevent frequent jittering of the comparator U2B output near the threshold, improving stability; the fifteenth resistor R15 is a pull-up resistor, pulling the comparator U2B output to VCC to ensure high-level drive capability; and the eighth capacitor C8 is an output filter capacitor, smoothing the Fre_Ctrl signal output by comparator U2B and reducing noise.

[0016] Furthermore, such as Figure 1 As shown, the filter circuit includes: a tenth resistor R10, a sixth capacitor C6, an eleventh resistor R11, and a seventh capacitor C7. One end of the tenth resistor R10 is connected to the PWM control chip U1, and the other end of the tenth resistor R10 is connected to one end of the sixth capacitor C6 and one end of the eleventh resistor R11. The other end of the sixth capacitor C6 is grounded. The other end of the eleventh resistor R11 is connected to the inverting input of comparator U2B and one end of the seventh capacitor C7. The other end of the seventh capacitor C7 is grounded. The tenth resistor R10, the sixth capacitor C6, the eleventh resistor R11, and the seventh capacitor C7 form an RC low-pass filter, converting the PWM signal into a DC voltage proportional to its duty cycle.

[0017] Furthermore, such as Figure 1 As shown, the voltage divider circuit includes: a twelfth resistor R12 and a thirteenth resistor R13; one end of the twelfth resistor R12 is connected to pin 2 of the PWM control chip U1, and the other end of the twelfth resistor R12 is connected to one end of the thirteenth resistor R13 and the non-inverting input of comparator U2B; one end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14, and the other end of the thirteenth resistor R13 is grounded. The twelfth resistor R12 and the thirteenth resistor R13 are voltage divider resistors, providing a fixed reference voltage threshold for the non-inverting input of comparator U2B.

[0018] Furthermore, such as Figure 1 As shown, an intelligent frequency conversion circuit for welding equipment according to an embodiment of the present invention further includes: a current detection circuit, which is connected to a PWM control chip U1 and is used for current detection. The current detection circuit includes: a transistor Q1, a ninth capacitor C9, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a current detection signal output interface CT; the collector of transistor Q1 is connected to pin 2 of the PWM control chip U1, the base of transistor Q1 is connected to pin 8 of the PWM control chip U1 and one end of the ninth capacitor C9, and the emitter of transistor Q1 is connected to one end of the sixth resistor R6; the other end of the ninth capacitor C9 is grounded; the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7, one end of the eighth resistor R8, and pin 4 of the PWM control chip U1; the other end of the seventh resistor R7 is connected to the current detection signal output interface CT; one end of the ninth resistor R9 is connected between one end of the eighth resistor R8 and pin 4 of the PWM control chip U1, and the other ends of the ninth resistor R9 and the other ends of the eighth resistor R8 are grounded. In this circuit, transistor Q1 serves as the current sensing or driving amplifier; resistors R6, R7, R8, and R9 form the current sensing network. Resistor R6 is the main current sampling resistor, while R7, R8, and R9 form a voltage divider and filter network, sending the sampled voltage to the PWM control chip U1 for current sensing and overcurrent protection; capacitor C6 is the filter capacitor to remove high-frequency noise from the current sensing signal; and the current sensing signal output interface CT can be used for external monitoring or protection circuits.

[0019] In this scheme, a Schmitt trigger is mainly implemented based on comparator U2B. When the output duty cycle is lower than the low threshold voltage VL, the Fre_Ctrl signal is high, shorting the fourth resistor R4 to ground, thereby reducing the frequency resistance of the PWM control chip U1 and thus increasing the frequency. When the output duty cycle is higher than the high threshold voltage VH, the Fre_Ctrl signal is low, connecting the fourth resistor R4 in parallel across the fifth resistor R5, thereby increasing the frequency resistance of the PWM control chip U1 and thus decreasing the frequency.

[0020] Above, refer to Figure 1 An intelligent frequency conversion circuit for welding equipment according to an embodiment of the present invention is described, and an intelligent frequency conversion scheme is proposed, which enables the machine to change its frequency according to its own needs and improve the efficiency.

[0021] It should be noted that, in this specification, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0022] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. An intelligent frequency conversion circuit for use in welding equipment, characterized in that, Includes: PWM control chip, frequency control circuit and current detection circuit; The frequency control circuit is connected to the PWM control chip and is used to control the frequency of the PWM control chip. The current detection circuit is connected to the PWM control chip and is used for current detection; The frequency control circuit includes: a filter circuit, a comparator, a voltage divider circuit, a fourteenth resistor, a fifteenth resistor, an eighth capacitor, a fourth resistor, a fifth resistor, and a MOSFET; The input terminal of the filter circuit is connected to the PWM control chip, and is used to receive the PWM output signal of the PWM control chip and convert the PWM output signal into DC voltage; The inverting input of the comparator is connected to the output of the filter circuit. The voltage divider circuit is connected to the PWM control chip and the non-inverting input of the comparator, and is used to provide a fixed reference voltage threshold for the comparator. One end of the fourteenth resistor is connected to the voltage divider circuit, and the other end of the fourteenth resistor is connected to the output terminal of the comparator. One end of the fifteenth resistor and one end of the eighth capacitor are connected to the output terminal of the comparator, the other end of the fifteenth resistor is connected to VCC voltage, and the other end of the eighth capacitor is grounded. One end of the fourth resistor and one end of the fifth resistor are connected to pin 9 of the PWM control chip, the other end of the fifth resistor is connected to pin 3 of the PWM control chip, and the other end of the fourth resistor is connected to the drain of the MOS transistor. The gate of the MOS transistor is connected to the output of the comparator, and the source of the MOS transistor is grounded.

2. The intelligent frequency conversion circuit for welding equipment as described in claim 1, characterized in that, The filter circuit includes: a tenth resistor, a sixth capacitor, an eleventh resistor, and a seventh capacitor; One end of the tenth resistor is connected to the PWM control chip, and the other end of the tenth resistor is connected to one end of the sixth capacitor and one end of the eleventh resistor; The other end of the sixth capacitor is grounded; The other end of the eleventh resistor is connected to the inverting input of the comparator and one end of the seventh capacitor; The other end of the seventh capacitor is grounded.

3. The intelligent frequency conversion circuit for welding equipment as described in claim 1, characterized in that, The voltage divider circuit includes: a twelfth resistor and a thirteenth resistor; One end of the twelfth resistor is connected to pin 2 of the PWM control chip, and the other end of the twelfth resistor is connected to one end of the thirteenth resistor and the non-inverting input of the comparator. One end of the thirteenth resistor is connected to one end of the fourteenth resistor, and the other end of the thirteenth resistor is grounded.

4. The intelligent frequency conversion circuit for welding equipment as described in claim 1, characterized in that, The current detection circuit includes: a transistor, a ninth capacitor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a current detection signal output interface; The collector of the transistor is connected to pin 2 of the PWM control chip, the base of the transistor is connected to pin 8 of the PWM control chip and one end of the ninth capacitor, and the emitter of the transistor is connected to one end of the sixth resistor. The other end of the ninth capacitor is grounded. The other end of the sixth resistor is connected to one end of the seventh resistor, one end of the eighth resistor, and pin 4 of the PWM control chip; The other end of the seventh resistor is connected to the current detection signal output interface; One end of the ninth resistor is connected between one end of the eighth resistor and pin 4 of the PWM control chip, and the other end of the ninth resistor and the other end of the eighth resistor are grounded.

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