Circuit for realizing bus voltage stabilization through superposition of power factor correction and secondary feedback of electric welding machine

Abstract

The utility model discloses a circuit for realizing bus voltage stabilization through superposition of power factor correction and secondary feedback of an electric welding machine. The circuit comprises a PFC chip, an input protection circuit, a PFC correction circuit, a topological structure circuit, a load resistor and a secondary voltage feedback circuit, the input protection circuit is connected with the PFC chip, an external alternating current zero line and an alternating current live wire; the PFC correction circuit is connected with the PFC core, the AC zero line and the AC live line. The topological structure circuit is connected with the PFC correction circuit; one end of the load resistor is connected with the topological structure circuit, and the other end is grounded; and the secondary voltage feedback circuit is connected with the topological structure circuit and the PFC chip. According to the utility model, at the moment of sudden change of a load, an arc is disconnected, a load resistor becomes an open circuit, a no-load voltage enters through a fifth capacitor and a voltage-regulator tube, and then a feedback voltage is superposed on a pin 6 of a PFC chip through an optocoupler, that is, VCC passes through a ninth resistor, and at the moment, the chip can rapidly adjust the duty ratio, so that the output voltage is stabilized at VDC and is not changed.

Description

TECHNICAL FIELD

[0001] The utility model relates to electric welding machine circuit technical field especially relates to a kind of bus voltage stabilizing circuit of electric welding machine power factor correction superimposed secondary feedback implementation. BACKGROUND

[0002] In order to reduce power grid harmonic interference, more and more countries and regions have put forward the requirement of power factor for electrical products, and there are various power factor correction chips on the market.

[0003] But in the use scene of electric welding machine, load RL is actually an arc, since the process of welding is intermittent, so there is a big load to small load or no-load switching constantly;When user is welding, output current is very large, at the moment of stopping welding, machine will enter no-load state, at this time, due to the energy storage of transformer, reflected voltage is generated, bus voltage VDC will suddenly rise, the rising voltage can damage diode D1, capacitors C3, C4 and full-bridge inverter circuit, in order to reduce the influence, a kind of bus voltage stabilizing circuit of electric welding machine power factor correction superimposed secondary feedback implementation is designed. SUMMARY

[0004] According to the utility model embodiment, a kind of bus voltage stabilizing circuit of electric welding machine power factor correction superimposed secondary feedback implementation is provided, include: PFC chip, input protection circuit, PFC correction circuit, topology structure circuit, load resistance and secondary voltage feedback circuit;

[0005] Input protection circuit is connected with the pin 5 of PFC chip, external AC neutral line, AC live wire, for input voltage signal to PFC chip;

[0006] PFC correction circuit is connected with the pin 1 of PFC chip, 8 and AC neutral line, AC live wire, for correcting input current;

[0007] Topology structure circuit is connected with PFC correction circuit;

[0008] One end of load resistance is connected with topology structure circuit, and the other end is grounded;

[0009] Secondary voltage feedback circuit is connected with topology structure circuit, the pin 6 of PFC chip, for superimposing a feedback voltage in the pin of PFC chip.

[0010] Further, input protection circuit includes: first diode, second diode, first resistance, second resistance, third resistance and first capacitor;

[0011] The anode of first diode is connected with AC neutral line;

[0012] Anode of the second diode is connected with the AC live wire, and the cathode of the second diode is connected with the cathode of the first diode, then sequentially passes through the first resistor, the second resistor and is connected with the pin 5 of the PFC chip;

[0013] One end of the third resistor is connected between the second resistor and the pin 5 of the PFC chip;

[0014] One end of the first capacitor is connected between one end of the third resistor and the pin 5 of the PFC chip, and the other end of the first capacitor is connected with the other end of the third resistor, and then is connected with the pin 2 of the PFC chip.

[0015] Further, it further comprises a fourth resistor and a second capacitor;

[0016] One end of the fourth resistor is connected with the pin 3 of the PFC chip, and the other end is connected with the other end of the third resistor, the other end of the first capacitor and the pin 2 of the PFC chip;

[0017] One end of the second capacitor is connected with the pin 3 of the PFC chip, and the other end is connected with the pin 2 of the PFC chip.

[0018] Further, the PFC correction circuit comprises a rectifier bridge, an inductor, a third diode, an IGBT device, a third capacitor, a fourth capacitor, a shunt resistor, a fifth resistor, a sixth resistor and a seventh resistor;

[0019] Two input ends of the rectifier bridge are connected with the AC live wire and the AC zero line respectively;

[0020] One end of the inductor is connected with one output end of the rectifier bridge;

[0021] Anode of the third diode is connected with the other end of the inductor, and the cathode of the third diode is connected with the topology structure circuit;

[0022] The third capacitor and the fourth capacitor are connected in parallel, and one end of the third capacitor and the fourth capacitor is connected between the cathode of the third diode and the topology structure circuit;

[0023] One end of the shunt resistor is connected with the other output end of the rectifier bridge, and the other end of the shunt resistor is sequentially connected with one end of the fifth resistor, the emitter of the IGBT device, the other end of the third capacitor, the other end of the fourth capacitor, and then is connected with the topology structure circuit;

[0024] The collector of the IGBT device is connected between the other end of the inductor and the anode of the third diode, and the gate of the IGBT device is connected with the pin 8 of the PFC chip through the sixth resistor;

[0025] The other end of the fifth resistor is connected between the gate of the IGBT device and the sixth resistor;

[0026] One end of the seventh resistor is connected between the other output end of the rectifier bridge and one end of the shunt resistor, and the other end of the seventh resistor is connected with the pin 1 of the PFC chip.

[0027] Further, the topology circuit comprises: a full-bridge inverter, a main transformer, a fourth diode and a fifth diode;

[0028] The full-bridge inverter is connected with the PFC correction circuit;

[0029] The pins 1 and 2 of the main transformer are connected with the full-bridge inverter, the pin 3 of the main transformer is connected with the anode of the fourth diode, the pin 4 of the main transformer is connected with the other end of the load resistor and then grounded, and the pin 5 of the main transformer is connected with the anode of the fifth diode;

[0030] The cathode of the fourth diode is connected with the cathode of the fifth diode and then connected with the other end of the load resistor and the secondary voltage feedback circuit.

[0031] Further, the secondary voltage feedback circuit comprises: a fifth capacitor, a voltage stabilizing diode, an eighth resistor, an optical coupler, a ninth resistor and a tenth resistor;

[0032] One end of the fifth capacitor is connected with the topology circuit and one end of the load resistor;

[0033] The cathode of the voltage stabilizing diode is connected with the other end of the fifth capacitor, and the other end of the voltage stabilizing diode is connected with the pin 1 of the optical coupler through the eighth resistor;

[0034] The pin 4 of the optical coupler is connected with the VCC terminal through the ninth resistor, the pin 2 of the optical coupler is connected with one end of the tenth resistor and then grounded, and the pin 3 of the optical coupler is connected with the pin 6 of the PFC chip;

[0035] The other end of the tenth resistor is connected between the pin 1 of the optical coupler and the ninth resistor.

[0036] Further, it further comprises: an eleventh resistor, a twelfth resistor and a thirteenth resistor;

[0037] One end of the eleventh resistor is connected between the topology circuit and the PFC correction circuit;

[0038] One end of the twelfth resistor is connected with the other end of the eleventh resistor;

[0039] One end of the thirteenth resistor is grounded, and the other end of the thirteenth resistor and the other end of the twelfth resistor are both connected between the pin 3 of the optical coupler and the pin 6 of the PFC chip.

[0040] According to the circuit for realizing bus voltage stabilization by power factor correction superimposed secondary feedback of the welding machine, in the moment of load mutation, the electric arc is disconnected, the load resistance becomes open circuit, the no-load voltage enters the feedback loop through the fifth capacitor and the voltage stabilizing tube, the feedback loop superimposes a feedback voltage through the optical coupling at the pin 6 of the PFC chip, namely VCC through the ninth resistance, at this time the chip will quickly adjust the duty cycle, so that the output voltage is stabilized at VDC unchanged.

[0041] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the subject technology claimed. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the subject technology claimed. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present application will be described below in detail with reference to the accompanying drawings, and the present application will be further described.

[0044] Firstly, the circuit for realizing bus voltage stabilization by power factor correction superimposed secondary feedback of the welding machine according to the embodiments of the present application will be described in combination with Figure 1 The circuit for realizing bus voltage stabilization by power factor correction superimposed secondary feedback of the welding machine according to the embodiments of the present application is used in the welding machine, and has a wide application scenario.

[0045] As shown in Figure 1 The circuit for realizing bus voltage stabilization by power factor correction superimposed secondary feedback of the welding machine according to the embodiments of the present application has a PFC chip U1, an input protection circuit, a PFC correction circuit in BOOST mode, a topology structure circuit, a load resistance RL and a secondary voltage feedback circuit.

[0046] Specifically, as shown in Figure 1 The VSENSE pin of the PFC chip U1 is a voltage feedback pin, collects VDC voltage as feedback, and controls VDC voltage at a constant value.

[0047] Specifically, as shown in Figure 1As shown, the input protection circuit is connected with pin 5 of PFC chip U1, external AC neutral line AC-N and AC live line AC-L, for inputting voltage signal to PFC chip U1. The input protection circuit comprises first diode D3, second diode D2, first resistor R1, second resistor R2, third resistor R3 and first capacitor C2. The anode of first diode D3 is connected with AC neutral line AC-N; the anode of second diode D2 is connected with AC live line AC-L, and the cathode of second diode D2 is connected with the cathode of first diode D3, then connected with pin 5 of PFC chip U1 through first resistor R1 and second resistor R2 in sequence; one end of third resistor R3 is connected between second resistor R2 and pin 5 of PFC chip U1; one end of first capacitor C2 is connected between one end of third resistor R3 and pin 5 of PFC chip U1, and the other end of first capacitor C2 is connected with the other end of third resistor R3 and then connected with pin 2 of PFC chip U1.

[0048] Specifically, as shown in the figure, Figure 1 The PFC correction circuit is connected with pin 1, 8 of PFC chip and AC neutral line AC-N, AC live line AC-L, for correcting input current. The PFC correction circuit comprises rectifier bridge, inductor L1, third diode D1, IGBT device T1, third capacitor C3, fourth capacitor C4, shunt resistor Rshunt, fifth resistor R7, sixth resistor R6 and seventh resistor R4. Two input ends of rectifier bridge are connected with AC live line AC-L and AC neutral line AC-N respectively; one end of inductor L1 is connected with one output end of rectifier bridge; the anode of third diode D1 is connected with the other end of inductor L1, and the cathode of third diode D1 is connected with topology structure circuit; third capacitor C3 and fourth capacitor C4 are connected in parallel, and one end of third capacitor C3 and fourth capacitor C4 is connected between the cathode of third diode D1 and topology structure circuit; one end of shunt resistor Rshunt is connected with the other output end of rectifier bridge, and the other end of shunt resistor Rshunt is connected with one end of fifth resistor R7, emitter of IGBT device T1, the other end of third capacitor C3, the other end of fourth capacitor C4 in sequence and then connected with topology structure circuit; the collector of IGBT device T1 is connected between the other end of inductor L1 and the anode of third diode D1, and the gate of IGBT device T1 is connected with pin 8 of PFC chip U1 through sixth resistor R6; the other end of fifth resistor R7 is connected between the gate of IGBT device T1 and sixth resistor R6; one end of seventh resistor R4 is connected between the other output end of rectifier bridge and one end of shunt resistor Rshunt, and the other end of seventh resistor R4 is connected with pin 1 of PFC chip U1.

[0049] Specifically, as shown in the figure, Figure 1As shown in the figure, the topology circuit is connected with the PFC correction circuit. The topology circuit comprises a full-bridge inverter, a main transformer TR1, a fourth diode D4 and a fifth diode D5. The full-bridge inverter is connected with the PFC correction circuit; a pin 1 and a pin 2 of the main transformer TR1 are connected with the full-bridge inverter, a pin 3 of the main transformer TR1 is connected with an anode of the fourth diode D4, a pin 4 of the main transformer TR1 is connected with the other end of the load resistor RL and then grounded, a pin 5 of the main transformer TR1 is connected with an anode of the fifth diode D5; a cathode of the fourth diode D4 and a cathode of the fifth diode D5 are connected and then connected with the other end of the load resistor RL and a secondary voltage feedback circuit.

[0050] Specifically, as shown in the figure, one end of the load resistor RL is connected with the topology circuit, and the other end is grounded. Figure 1

[0051] Specifically, as shown in the figure, the secondary voltage feedback circuit is connected with the topology circuit and a pin 6 of the PFC chip U1, and is used for superimposing a feedback voltage on the pin of the PFC chip U1. The secondary voltage feedback circuit comprises a fifth capacitor C5, a first zener diode Z1, an eighth resistor R12, an optical coupler EL1, a ninth resistor R11 and a tenth resistor R13; one end of the fifth capacitor C5 is connected with the topology circuit and one end of the load resistor RL; a cathode of the zener diode is connected with the other end of the fifth capacitor C5, and the other end of the zener diode is connected with a pin 1 of the optical coupler EL1 through the eighth resistor R12; a pin 4 of the optical coupler EL1 is connected with a VCC terminal through the ninth resistor R11, a pin 2 of the optical coupler EL1 is connected with the other end of the tenth resistor R13 and then grounded, a pin 3 of the optical coupler EL1 is connected with the pin 6 of the PFC chip U1; the other end of the tenth resistor R13 is connected between the pin 1 of the optical coupler EL1 and the ninth resistor R11. Figure 1

[0052] Further, as shown in the figure, the circuit for realizing bus voltage stabilization by power factor correction superimposition secondary feedback of the electric welding machine further comprises a fourth resistor R3 and a second capacitor C2; one end of the fourth resistor R3 is connected with a pin 3 of the PFC chip U1, the other end of the fourth resistor R3 is connected with the other end of the third resistor R3, the other end of the first capacitor C2 and a pin 2 of the PFC chip U1; one end of the second capacitor C2 is connected with the pin 3 of the PFC chip U1, and the other end of the second capacitor C2 is connected with the pin 2 of the PFC chip U1. Figure 1

[0053] Further, as shown in the figure, the circuit for realizing bus voltage stabilization by power factor correction superimposition secondary feedback of the electric welding machine further comprises a fourth resistor R3 and a second capacitor C2; one end of the fourth resistor R3 is connected with a pin 3 of the PFC chip U1, the other end of the fourth resistor R3 is connected with the other end of the third resistor R3, the other end of the first capacitor C2 and a pin 2 of the PFC chip U1; one end of the second capacitor C2 is connected with the pin 3 of the PFC chip U1, and the other end of the second capacitor C2 is connected with the pin 2 of the PFC chip U1. Figure 1 ​​​The utility model discloses a welding machine power factor correction superimposed secondary feedback realizes bus voltage stabilizing circuit still contain: eleventh resistance R8, twelfth resistance R9 and thirteenth resistance R10, the resistance one end of eleventh is connected between topology structure circuit and PFC correction circuit, one end of twelfth resistance R9 is connected with the other end of eleventh resistance R8, one end of thirteenth resistance R10 is grounded, and the other end of thirteenth resistance R10 and the other end of twelfth resistance R9 are all connected between the pin 3 of photoelectric coupler EL1 and the pin 6 of PFC chip U1.

[0054] The application focuses on designing a secondary voltage feedback circuit, in the moment of load mutation, arc is disconnected, load resistance RL becomes open circuit, no-load voltage passes through fifth capacitor C5, first voltage stabilizing tube Z1 and enters feedback loop, and the feedback loop superimposes a feedback voltage through photoelectric coupler EL1 at the pin 6 of PFC chip U1, that is, VCC passes through ninth resistance R11, at this moment, the chip will quickly adjust duty ratio, and makes output voltage stable at VDC unchanged.

[0055] It should be noted that in the present specification, the terms "comprising", "containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0056] Although the content of the utility model has been introduced in detail through the above preferred embodiment, it should be recognized that the above description should not be considered as the limitation of the utility model. After the above content is read by the person skilled in the art, various modifications and substitutions of the utility model will be obvious. Therefore, the protection scope of the utility model should be limited by the attached claims.

Claims

1. A circuit for achieving bus voltage stabilization by superimposing power factor correction and secondary feedback in an electric welding machine, characterized in that, Includes: PFC chip, input protection circuit, PFC correction circuit, topology circuit, load resistor and secondary voltage feedback circuit; The input protection circuit is connected to pin 5 of the PFC chip, the external AC neutral wire, and the AC live wire, and is used to input voltage signals to the PFC chip. The PFC correction circuit is connected to pins 1 and 8 of the PFC core, as well as the AC neutral wire and the AC live wire, and is used to correct the input current. The topology circuit is connected to the PFC correction circuit; One end of the load resistor is connected to the topology circuit, and the other end is grounded; The secondary voltage feedback circuit is connected to the topology circuit and pin 6 of the PFC chip, and is used to superimpose a feedback voltage on the pin of the PFC chip.

2. The circuit for achieving bus voltage stabilization by superimposing power factor correction and secondary feedback in a welding machine as described in claim 1, characterized in that, The input protection circuit includes: a first diode, a second diode, a first resistor, a second resistor, a third resistor, and a first capacitor; The anode of the first diode is connected to the AC neutral wire; The anode of the second diode is connected to the AC live wire, and the cathode of the second diode is connected to the cathode of the first diode. Then, the second diode is connected to pin 5 of the PFC chip in sequence through the first resistor and the second resistor. One end of the third resistor is connected between the second resistor and pin 5 of the PFC chip. One end of the first capacitor is connected between one end of the third resistor and pin 5 of the PFC chip, and the other end of the first capacitor is connected to the other end of the third resistor and then connected to pin 2 of the PFC chip.

3. The circuit for achieving bus voltage stabilization by superimposing secondary feedback with power factor correction in an electric welding machine as described in claim 2, characterized in that, It also includes: a fourth resistor and a second capacitor; One end of the fourth resistor is connected to pin 3 of the PFC chip, and the other end is connected to the other end of the third resistor, the other end of the first capacitor, and pin 2 of the PFC chip. One end of the second capacitor is connected to pin 3 of the PFC chip, and the other end is connected to pin 2 of the PFC chip.

4. The circuit for achieving bus voltage stabilization by superimposing secondary feedback with power factor correction in an electric welding machine as described in claim 1, characterized in that, The PFC correction circuit includes: a rectifier bridge, an inductor, a third diode, an IGBT device, a third capacitor, a fourth capacitor, a shunt resistor, a fifth resistor, a sixth resistor, and a seventh resistor; The two input terminals of the rectifier bridge are respectively connected to the AC live wire and the AC neutral wire; One end of the inductor is connected to one of the output terminals of the rectifier bridge; The anode of the third diode is connected to the other end of the inductor, and the cathode of the third diode is connected to the topology circuit. The third capacitor is connected in parallel with the fourth capacitor, and one end of each of the third capacitor and the fourth capacitor is connected between the cathode of the third diode and the topology circuit. One end of the shunt resistor is connected to the other output terminal of the rectifier bridge. The other end of the shunt resistor is connected in sequence to one end of the fifth resistor, the emitter of the IGBT device, the other end of the third capacitor, and the other end of the fourth capacitor, and then connected to the topology circuit. The collector of the IGBT device is connected between the other end of the inductor and the anode of the third diode, and the gate of the IGBT device is connected to pin 8 of the PFC chip through the sixth resistor. The other end of the fifth resistor is connected between the gate of the IGBT device and the sixth resistor; One end of the seventh resistor is connected between the other output terminal of the rectifier bridge and one end of the shunt resistor, and the other end of the seventh resistor is connected to pin 1 of the PFC chip.

5. The circuit for achieving bus voltage stabilization by superimposing secondary feedback with power factor correction of an electric welding machine as described in claim 1, characterized in that, The topology circuit includes: a full-bridge inverter, a main transformer, a fourth diode, and a fifth diode; The full-bridge inverter is connected to the PFC correction circuit. Pins 1 and 2 of the main transformer are connected to the full-bridge inverter, pin 3 of the main transformer is connected to the anode of the fourth diode, pin 4 of the main transformer is connected to the other end of the load resistor and then grounded, and pin 5 of the main transformer is connected to the anode of the fifth diode. After the cathode of the fourth diode is connected to the cathode of the fifth diode, it is connected to the other end of the load resistor and the secondary voltage feedback circuit.

6. The circuit for achieving bus voltage stabilization by superimposing secondary feedback with power factor correction in an electric welding machine as described in claim 1, characterized in that, The secondary voltage feedback circuit includes: a fifth capacitor, a Zener diode, an eighth resistor, an optocoupler, a ninth resistor, and a tenth resistor; One end of the fifth capacitor is connected to the topology circuit and one end of the load resistor; The cathode of the Zener diode is connected to the other end of the fifth capacitor, and the other end of the Zener diode is connected to pin 1 of the optocoupler through the eighth resistor; The optocoupler's pin 4 is connected to the VCC terminal through the ninth resistor, the optocoupler's pin 2 is connected to one end of the tenth resistor and then grounded, and the optocoupler's pin 3 is connected to the PFC chip's pin 6. The other end of the tenth resistor is connected between pin 1 of the optocoupler and the ninth resistor.

7. The circuit for achieving bus voltage stabilization by superimposing secondary feedback with power factor correction in an electric welding machine as described in claim 6, characterized in that, It also includes: the eleventh resistor, the twelfth resistor, and the thirteenth resistor; One end of the eleventh resistor is connected between the topology circuit and the PFC correction circuit; One end of the twelfth resistor is connected to the other end of the eleventh resistor; One end of the thirteenth resistor is grounded, and the other end of the thirteenth resistor and the other end of the twelfth resistor are both connected between pin 3 of the optocoupler and pin 6 of the PFC chip.

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