A boost circuit and working method suitable for high voltage input
By using alternate working power switch tubes and common inductors and diodes in the inverter welding machine, the problem that semiconductor devices with high voltage inputs are difficult to withstand high switching frequency, and an efficient and low-cost circuit design is achieved, which improves the performance and portability of the system.
Patent Information
- Application Number
- CN202411831203.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-04-04
AI Technical Summary
When existing inverter welding machines face high voltage input, semiconductor devices are difficult to withstand high switching frequency, resulting in complex design, high cost and increased number of components, affecting the reliability and portability of the system.
The boost circuit design is adopted, including a power supply module, a power conversion module and a filter output module, and the first power switch tube and the second power switch tube are alternately operated to increase the switching frequency, and reduce the number of components by a shared boost inductor and freewheeling diode.
It realizes the increase in switching frequency under high voltage input conditions, reduces the number of inductors and costs, simplifies circuit design, improves system performance and adaptability, and reduces failure rate and production costs.
Smart Images
Figure CN119765919A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of welding technology, and in particular to a boost circuit and a working method suitable for high voltage input. Background Art
[0002] In the field of welding technology, inverter welding machines are widely used. Its working principle is to first rectify the industrial frequency AC power to convert it into DC power, then convert the DC power into high-frequency AC power through the inverter circuit, and finally rectify it again to provide the required power for the welding operation. However, there are significant differences in the power supply voltage. This inconsistency poses a huge challenge to the versatility of inverter welding machines. When the inverter welding machine needs to be used in occasions with different power supply voltages, in order to avoid the cumbersomeness and high cost of separate design for each voltage, it is usually designed to be compatible with multiple voltage inputs.
[0003] In inverter welding machines with multi-voltage power supply, in order to ensure the best welding performance and highest efficiency under various input voltages, boost technology is generally used to convert different input voltages into a stable voltage output. Among them, the staggered parallel boost circuit is a more commonly used circuit form. However, as the input voltage continues to increase, the design difficulty of the boost circuit increases exponentially. On the one hand, high-voltage semiconductor devices are unable to cope with high switching frequencies and are difficult to bear. This is because high switching frequencies can have a serious impact on the performance and life of semiconductor devices, such as higher switching losses, increased heating problems, and possible electromagnetic interference. In order to overcome these problems, circuit design needs to take a series of complex measures, such as adding heat dissipation devices, optimizing circuit layout to reduce electromagnetic interference, etc., which undoubtedly makes circuit design extremely complicated. On the other hand, these additional design requirements and measures will inevitably lead to a significant increase in costs, including the cost of the semiconductor devices themselves, the cost of heat dissipation equipment, and the labor cost during research and development and debugging. Moreover, if Figure 1 As shown in the figure, although the staggered parallel circuit can cope with the challenge of high voltage input to a certain extent, it also has obvious defects, namely, the number of components increases significantly. A large number of components not only increases the volume and weight of the circuit, which is not conducive to the miniaturization and portability of the welding machine, but also increases the failure rate of the circuit, because each component may become a failure point, thereby reducing the reliability and stability of the entire system. In addition, more components also mean that more assembly processes and quality inspection links are required in the manufacturing process, further increasing production costs and production cycles. Summary of the invention
[0004] In view of the deficiencies in the prior art, the present invention provides a boost circuit and a working method suitable for high voltage input. The present invention solves the problem that high-voltage semiconductor devices cannot withstand high switching frequencies, reduces the number and inductance of inductors, and reduces costs and circuit complexity.
[0005] In order to achieve the above object, the present invention adopts the following technical solution:
[0006] In a first aspect, the present invention provides a boost circuit suitable for high voltage input, comprising: a power module, a power conversion module and a filter output module; wherein the output end of the power module is connected to the input end of the power conversion module, and the output end of the power conversion module is connected to the input end of the filter output module;
[0007] The power conversion module includes a boost inductor, a power switch tube and a freewheeling diode, wherein the boost inductor is connected in series with the power switch tube, and the power switch tube is also connected in series with the freewheeling diode. Two power switch tubes are provided, namely a first power switch tube and a second power switch tube, and the first power switch tube and the second power switch tube are connected in parallel. After being connected in parallel, the collectors of the first power switch tube and the second power switch tube are connected to the anode of the freewheeling diode together.
[0008] As a further technical solution, the power supply module includes an AC power supply and a rectifier and filter circuit, the rectifier and filter circuit includes a rectifier bridge and a first capacitor; the output end of the power supply module is the output end of the rectifier and filter circuit, specifically: one end of the first capacitor is connected to one end of the boost inductor, and the other end of the first capacitor is respectively connected to the emitters of the first power switch tube and the second power switch tube.
[0009] As a further technical solution, the filter output module includes a second capacitor, one end of which is connected to the cathode of the freewheeling diode, and the other end of the second capacitor is respectively connected to the emitters of the first power switch tube and the second power switch tube.
[0010] As a further technical solution, in the power conversion module, specifically: one end of the boost inductor is connected to one end of the power module, and the other end of the boost inductor is respectively connected to the collectors of the first power switch tube and the second power switch tube; the emitters of the first power switch tube and the second power switch tube are connected to the other end of the power module.
[0011] As a further technical solution, the power conversion module is further connected to a drive circuit, and the output end of the drive circuit is respectively connected to the first power switch tube and the second power switch tube for driving the first power switch tube and the second power switch tube.
[0012] As a further technical solution, the drive circuit includes a PWM controller, a full-bridge circuit, and a transformer connected in sequence; the full-bridge circuit consists of a first bridge arm and a second bridge arm, and two switching tubes are connected in series on the first bridge arm and the second bridge arm; the input ends of the first bridge arm and the second bridge arm are respectively connected to the output ends of the PWM controller, and the output ends of the first bridge arm and the second bridge arm are respectively connected to the two ends of the primary winding of the transformer, and the primary winding of the transformer is coupled with a secondary winding.
[0013] As a further technical solution, the transformer is provided with two secondary windings, namely a first secondary winding and a second secondary winding; the first secondary winding is connected to a first switch tube drive circuit, and the second secondary winding is connected to a second switch tube drive circuit; the output end of the first switch tube drive circuit is connected to a first power switch tube, and the output end of the second switch tube drive circuit is connected to a second power switch tube; the drive signals output by the first switch tube drive circuit and the second switch tube drive circuit are complementary, and a suitable dead time is reserved to avoid the first power switch tube and the second power switch tube being turned on at the same time.
[0014] As a further technical solution, the first switch tube driving circuit includes a first shutdown module, a first turn-on module and a first filtering module, wherein the first shutdown module includes a first diode and a first shutdown discharge resistor connected in series, the first turn-on module includes a first turn-on resistor connected in parallel at both ends of the first shutdown module, and the first filtering module includes a third capacitor. Specifically: the first end of the first secondary winding is respectively connected to the cathode of the first diode and one end of the first turn-on resistor, the anode of the first diode is connected to one end of the first turn-off discharge resistor, the other end of the first turn-off discharge resistor and the other end of the first turn-on resistor are commonly connected to one end of the third capacitor, and the other end of the third capacitor is connected to the second end of the first secondary winding.
[0015] As a further technical solution, the second switch tube driving circuit includes a second shutdown module, a second turn-on module and a second filtering module, wherein the second shutdown module includes a second diode and a second shutdown discharge resistor connected in series, the second turn-on module includes a second turn-on resistor connected in parallel at both ends of the second shutdown module, and the second filtering module includes a fourth capacitor. Specifically: the first end of the second secondary winding is respectively connected to the cathode of the second diode and one end of the second turn-on resistor, the anode of the second diode is connected to one end of the second turn-off discharge resistor, the other end of the second turn-off discharge resistor and the other end of the second turn-on resistor are commonly connected to one end of the fourth capacitor, and the other end of the fourth capacitor is connected to the second end of the second secondary winding.
[0016] In a second aspect, the present invention provides a working method of a boost circuit suitable for high voltage input, based on a boost circuit suitable for high voltage input described in any one of the first aspects, comprising: when the first power switch tube is turned on, the boost inductor is charged, the current of the boost inductor increases linearly, the boost inductor stores energy, and the current flows through one end of the first capacitor, the boost inductor, the first power switch tube, and the other end of the first capacitor in sequence; when the first power switch tube is turned off, the boost inductor generates an induced electromotive force with a polarity of negative on the left and positive on the right, charging the second capacitor, and the current flows through the boost inductor, the freewheeling diode, and the second capacitor in sequence; the first power switch tube and the second power switch tube work alternately, and when the second power switch tube is turned on, the boost inductor is charged again, and the current flows through one end of the first capacitor, the boost inductor, the second power switch tube, and the other end of the first capacitor in sequence; when the second power switch tube is turned off, the boost inductor is discharged.
[0017] One or more technical solutions of the present invention have the following beneficial effects:
[0018] (1) The present invention cleverly achieves an increase in switching frequency by alternately operating the first power switch tube and the second power switch tube. The switching frequencies of the first power switch tube and the second power switch tube in the circuit are both set to fsw. When the two switches are connected in parallel, the equivalent switching frequency can be doubled to 2fsw. This high-frequency switching working mode brings many advantages. During the power conversion process, a higher switching frequency can make the conversion of electric energy more efficient and smooth, reducing the loss and fluctuation of energy during the conversion process. At the same time, it effectively solves the problem that high-voltage semiconductor devices cannot withstand high switching frequencies in traditional designs, allowing the circuit to operate stably at a higher frequency, thereby improving the performance and adaptability of the entire boost circuit.
[0019] (2) In the circuit provided by the present invention, the first power switch tube and the second power switch tube use a boost inductor. This design innovation enables the inductance to be significantly reduced. As the switching frequency increases, the inductance is reduced a lot. Smaller inductance has many advantages. First, in terms of physical size, the volume of the inductor is greatly reduced, which is of great significance for achieving miniaturization and lightweight of equipment, especially in equipment such as inverter welding machines that need to be frequently moved and operated. Reducing the volume can improve the portability and flexibility of the equipment. From a cost perspective, the reduction in inductance means that smaller and lower-cost inductor components can be used, which directly reduces material costs. In addition, the smaller inductor has a faster energy storage and release process in the circuit, which can better match the rhythm of high-frequency switching, reduce the energy retention time in the inductor, further improve the overall efficiency of the circuit, reduce energy loss, and help extend the battery life of the equipment or reduce energy consumption.
[0020] (3) In the circuit provided by the present invention, the first power switch tube and the second power switch tube share a freewheeling diode. This design directly reduces the number of diodes used. As one of the key components in the circuit, the cost of the diode accounts for a certain proportion of the total circuit cost. By reducing the use of diodes, not only the component procurement cost is reduced, but also space is saved in the circuit board layout, the area and number of layers of the circuit board are reduced, and thus the manufacturing cost of the circuit board is reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.
[0022] Figure 1 A circuit diagram of an interleaved parallel circuit in the prior art;
[0023] Figure 2 is a circuit diagram of a voltage boost circuit of the present invention;
[0024] Figure 3 is a circuit diagram of a driving circuit of the present invention;
[0025] Figure 4 This is a driving strategy diagram of the first power switch tube and the second power switch tube of the present invention. DETAILED DESCRIPTION
[0026] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.
[0027] Embodiment 1
[0028] This embodiment provides a boost circuit suitable for high voltage input, such as Figure 2As shown, the boost circuit includes a power module, a power conversion module and a filter output module; wherein the output end of the power module is connected to the input end of the power conversion module, and the output end of the power conversion module is connected to the input end of the filter output module; the power conversion module includes a boost inductor RA1, a power switch tube and a freewheeling diode RB1, wherein in the power conversion module, the boost inductor RA1 is connected in series with the power switch tube, and the power switch tube is also connected in series with the freewheeling diode RB1, specifically: two power switch tubes are provided, namely the first power switch tube Q1 and the second power switch tube Q2, and the first power switch tube and the second power switch tube are connected in parallel, and after being connected in parallel, the collectors of the first power switch tube and the second power switch tube are connected to the anode of the freewheeling diode together. The principle of the boost circuit is: when the first power switch tube Q1 is turned on, the input power supply (rectified direct current) charges the boost inductor RA1, at which time the inductor current increases linearly, the inductor stores energy, and the current path is: the positive electrode of the input power supply (one end of the first capacitor) → RA1 → Q1 → the negative electrode of the input power supply (the other end of the first capacitor). When the first power switch tube Q1 is turned off, since the inductor current cannot change suddenly, the inductor generates an induced electromotive force with a polarity of negative on the left and positive on the right. At this time, the inductor is connected in series with the input power supply to supply power to the load and charge the second capacitor C1. The current path is: boost inductor RA1→freewheeling diode RB1→second capacitor C1→load→negative pole of input power supply. Q2 and Q1 work alternately. When Q2 is turned on, the input power supply charges the inductor again. The current path is: positive pole of input power supply→boost inductor RA1→Q2→negative pole of input power supply; when Q2 is turned off, the inductor discharges to supply power to the load. The current path is similar to when Q1 is turned off, except that the switch tube through which the current flows becomes Q2. It can be seen that the first power switch tube and the second power switch tube use a boost inductor. This design innovation enables the inductance to be significantly reduced. As the switching frequency increases, the inductance can be reduced a lot. Smaller inductance has many advantages. First, in terms of physical size, the volume of the inductor is greatly reduced, which is of great significance for achieving miniaturization and lightweight of the equipment, especially in equipment such as inverter welding machines that need to be frequently moved and operated. Reducing the volume can improve the portability and flexibility of the equipment. From a cost perspective, the reduction in inductance means that smaller and lower-cost inductor components can be used, which directly reduces the material cost. In addition, the smaller inductor has a faster energy storage and release process in the circuit, which can better match the rhythm of high-frequency switching, reduce the energy retention time in the inductor, further improve the overall efficiency of the circuit, reduce energy loss, and help extend the battery life of the equipment or reduce energy consumption. In this embodiment, the first power switch tube and the second power switch tube share a freewheeling diode. This design directly reduces the number of diodes used. As one of the key components in the circuit, the cost of the diode accounts for a certain proportion of the total circuit cost.By reducing the use of diodes, not only the component procurement cost is reduced, but also space is saved on the circuit board layout, the area and number of layers of the circuit board are reduced, thereby reducing the manufacturing cost of the circuit board.
[0029] Specifically in this embodiment: the power module includes an AC power supply and a simple rectifier filter circuit. The function of the rectifier filter circuit is to convert the input AC power into DC power and filter it. Figure 2 As shown, the rectifier filter circuit includes a rectifier bridge and a first capacitor, the output end of the power module is the output end of the rectifier filter circuit, one end of the first capacitor is connected to one end of the boost inductor, and the other end of the first capacitor is respectively connected to the emitters of the first power switch tube and the second power switch tube. After the AC passes through the rectifier filter circuit, it becomes DC power, and the low-voltage DC power is converted into high-voltage DC power through the power conversion module composed of the boost inductor RA1, the first power switch tube Q1, the second power switch tube Q2, and the freewheeling diode RB1. In the power conversion module, one end of the boost inductor RA1 is connected to one end of the power module, that is, one end of the boost inductor RA1 is connected to one end of the first capacitor, and the other end of the boost inductor is respectively connected to the collectors of the first power switch tube and the second power switch tube; the emitters of the first power switch tube and the second power switch tube are connected to the other end of the power module, that is, the emitters of the first power switch tube and the second power switch tube are connected to the other end of the first capacitor. The filter output module includes a second capacitor. Specifically, one end of the second capacitor is connected to the cathode of the freewheeling diode, and the other end of the second capacitor is connected to the emitter of the first power switch tube and the emitter of the second power switch tube respectively.
[0030] In order to improve the switching frequency in this embodiment, Figure 4 As shown in the driving strategy diagram, this embodiment designs the first power switch tube and the second power switch tube to work alternately, and the power conversion module is also connected to a driving circuit, and the output end of the driving circuit is respectively connected to the first power switch tube Q1 and the second power switch tube Q2, for driving the first power switch tube and the second power switch tube to work alternately. In this embodiment, as Figure 3As shown, the driving circuit includes a PWM controller, a full-bridge circuit, and a transformer connected in sequence, wherein the PWM controller can be selected from the existing technology, and the full-bridge circuit is composed of a first bridge arm and a second bridge arm, and two switching tubes are connected in series on the first bridge arm and the second bridge arm, and the entire full-bridge circuit is composed of four switching tubes. In this embodiment, the switching tube is MOSFET, which has a fast switching speed and low loss. The input ends of the first bridge arm and the second bridge arm are respectively connected to the output ends of the PWM controller, and the output ends of the first bridge arm and the second bridge arm are respectively connected to the two ends of the primary winding of the transformer, and the primary winding of the transformer is coupled and connected with the secondary winding. Specifically: since the structures of the first bridge arm and the second bridge arm are the same, the first bridge arm is taken as an example in this embodiment, and the first bridge arm is composed of a first switch tube and a second switch tube connected in series. One output end of the PWM controller is connected to the gate of the first switch tube and the second switch tube through a resistor, respectively, the drain of the first switch tube is connected to the power supply, the source of the first switch tube is connected to the drain of the second switch tube, and the source of the second switch tube is grounded. The on and off of the circuit is controlled by controlling the conduction and cutoff of the first switch tube and the second switch tube. The source of the first switch tube is connected to the drain of the second switch tube as an output and connected to one end of the primary winding of the transformer. The structure of the second bridge arm is similar. The transformer is provided with two secondary windings, namely a first secondary winding and a second secondary winding, wherein the first secondary winding is connected to a first switch tube driving circuit, the second secondary winding is connected to a second switch tube driving circuit, the output end of the first switch tube driving circuit is connected to the first power switch tube, and the output end of the second switch tube driving circuit is connected to the second power switch tube; specifically: the first switch tube driving circuit includes a first shutdown module, a first turn-on module and a first filter module, wherein the first shutdown module includes a first diode and a first shutdown discharge resistor connected in series, the first turn-on module includes a first turn-on resistor connected in parallel at both ends of the first shutdown module, and the first filter module includes a third capacitor, specifically: the first end of the first secondary winding is respectively connected to the cathode of the first diode and one end of the first turn-on resistor, the anode of the first diode is connected to one end of the first turn-off discharge resistor, the other end of the first turn-off discharge resistor and the other end of the first turn-on resistor are commonly connected to one end of the third capacitor, and the other end of the third capacitor is connected to the second end of the first secondary winding.The structure of the second switch tube driving circuit is the same as that of the first switch tube driving circuit. The second switch tube driving circuit includes a second shut-down module, a second turn-on module and a second filter module, wherein the second shut-down module includes a second diode and a second shut-down discharge resistor connected in series, the second turn-on module includes a second turn-on resistor connected in parallel at both ends of the second shut-down module, and the second filter module includes a fourth capacitor. Specifically, the first end of the second secondary winding is respectively connected to the cathode of the second diode and one end of the second turn-on resistor, the anode of the second diode is connected to one end of the second shut-down discharge resistor, the other end of the second shut-down discharge resistor and the other end of the second turn-on resistor are commonly connected to one end of the fourth capacitor, and the other end of the fourth capacitor is connected to the second end of the second secondary winding. The PWM controller generates a complementary pulse waveform, drives the full-bridge circuit to be converted into two complementary outputs after passing through the transformer, and finally drives the first power switch tube Q1 and the second power switch tube Q2 to work alternately through the first rectifier shunt filter circuit and the second rectifier shunt filter circuit, respectively. The two drive signals are 180° out of phase (complementary), and a suitable dead time is left, so that Q1 and Q2 will not be turned on at the same time.
[0031] Embodiment 2
[0032] In the present embodiment, a working method of a boost circuit suitable for high voltage input is provided, based on a boost circuit suitable for high voltage input in embodiment 1, comprising: when the first power switch tube is turned on, the boost inductor is charged, the current of the boost inductor increases linearly, the boost inductor stores energy, and the current flows through one end of the first capacitor, the boost inductor, the first power switch tube, and the other end of the first capacitor in sequence; when the first power switch tube is turned off, the boost inductor generates an induced electromotive force with a polarity of negative on the left and positive on the right, and charges the second capacitor, and the current flows through the boost inductor, the freewheeling diode, and the second capacitor in sequence; the first power switch tube and the second power switch tube work alternately, and when the second power switch tube is turned on, the boost inductor is charged again, and the current flows through one end of the first capacitor, the boost inductor, the second power switch tube, and the other end of the first capacitor in sequence; when the second power switch tube is turned off, the boost inductor is discharged.
[0033] In this embodiment, the voltage boosted by the boost circuit is inverted and used for welding. Specifically, the output end of the boost circuit can be connected to a full-bridge inverter or other forms of inverter circuits.
[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A boost circuit suitable for high voltage input, characterized in that: include: A power supply module, a power conversion module and a filter output module; wherein the output end of the power supply module is connected to the input end of the power conversion module, and the output end of the power conversion module is connected to the input end of the filter output module; The power conversion module includes a boost inductor, a power switch tube and a freewheeling diode, wherein the boost inductor is connected in series with the power switch tube, and the power switch tube is also connected in series with the freewheeling diode. Two power switch tubes are provided, namely a first power switch tube and a second power switch tube, and the first power switch tube and the second power switch tube are connected in parallel. After being connected in parallel, the collectors of the first power switch tube and the second power switch tube are connected to the anode of the freewheeling diode together.
2. A boost circuit suitable for high voltage input as claimed in claim 1, characterized in that: The power module includes an AC power supply and a rectifier and filter circuit, and the rectifier and filter circuit includes a rectifier bridge and a first capacitor; the output end of the power module is the output end of the rectifier and filter circuit, specifically: one end of the first capacitor is connected to one end of the boost inductor, and the other end of the first capacitor is respectively connected to the emitters of the first power switch tube and the second power switch tube.
3. A boost circuit suitable for high voltage input as claimed in claim 1, characterized in that: The filter output module includes a second capacitor, one end of which is connected to the cathode of the freewheeling diode, and the other end of which is connected to the emitters of the first power switch tube and the second power switch tube respectively.
4. A boost circuit suitable for high voltage input as claimed in claim 1, characterized in that: In the power conversion module, specifically: one end of the boost inductor is connected to one end of the power module, and the other end of the boost inductor is respectively connected to the collectors of the first power switch tube and the second power switch tube; the emitters of the first power switch tube and the second power switch tube are connected to the other end of the power module.
5. A boost circuit suitable for high voltage input as claimed in claim 1, characterized in that: The power conversion module is also connected to a driving circuit, and the output end of the driving circuit is respectively connected to the first power switch tube and the second power switch tube for driving the first power switch tube and the second power switch tube.
6. A boost circuit suitable for high voltage input as claimed in claim 5, characterized in that: The driving circuit includes a PWM controller, a full-bridge circuit, and a transformer connected in sequence; the full-bridge circuit consists of a first bridge arm and a second bridge arm, and two switching tubes are connected in series on the first bridge arm and the second bridge arm; the input ends of the first bridge arm and the second bridge arm are respectively connected to the output ends of the PWM controller, and the output ends of the first bridge arm and the second bridge arm are respectively connected to the two ends of the primary winding of the transformer, and the primary winding of the transformer is coupled and connected with the secondary winding.
7. A boost circuit suitable for high voltage input as claimed in claim 6, characterized in that: The transformer has two secondary windings, namely a first secondary winding and a second secondary winding; the first secondary winding is connected to a first switch tube drive circuit, and the second secondary winding is connected to a second switch tube drive circuit; the output end of the first switch tube drive circuit is connected to a first power switch tube, and the output end of the second switch tube drive circuit is connected to a second power switch tube; the drive signals output by the first switch tube drive circuit and the second switch tube drive circuit are complementary, and a suitable dead time is reserved to avoid the first power switch tube and the second power switch tube being turned on at the same time.
8. A boost circuit suitable for high voltage input as claimed in claim 7, characterized in that: The first switch tube driving circuit includes a first shutdown module, a first turn-on module and a first filtering module, wherein the first shutdown module includes a first diode and a first shutdown discharge resistor connected in series, the first turn-on module includes a first turn-on resistor connected in parallel at both ends of the first shutdown module, and the first filtering module includes a third capacitor. Specifically: the first end of the first secondary winding is respectively connected to the cathode of the first diode and one end of the first turn-on resistor, the anode of the first diode is connected to one end of the first turn-off discharge resistor, the other end of the first turn-off discharge resistor and the other end of the first turn-on resistor are commonly connected to one end of the third capacitor, and the other end of the third capacitor is connected to the second end of the first secondary winding.
9. A boost circuit suitable for high voltage input as claimed in claim 7, characterized in that: The second switch tube driving circuit includes a second shutdown module, a second turn-on module and a second filtering module, wherein the second shutdown module includes a second diode and a second shutdown discharge resistor connected in series, the second turn-on module includes a second turn-on resistor connected in parallel at both ends of the second shutdown module, and the second filtering module includes a fourth capacitor. Specifically: the first end of the second secondary winding is respectively connected to the cathode of the second diode and one end of the second turn-on resistor, the anode of the second diode is connected to one end of the second turn-off discharge resistor, the other end of the second turn-off discharge resistor and the other end of the second turn-on resistor are commonly connected to one end of the fourth capacitor, and the other end of the fourth capacitor is connected to the second end of the second secondary winding.
10. A working method of a boost circuit suitable for high voltage input, based on a boost circuit suitable for high voltage input according to any one of claims 1 to 9, characterized in that: include: When the first power switch tube is turned on, the boost inductor is charged, the current of the boost inductor increases linearly, the boost inductor stores energy, and the current flows through one end of the first capacitor, the boost inductor, the first power switch tube, and the other end of the first capacitor in sequence; when the first power switch tube is turned off, the boost inductor generates an induced electromotive force with a polarity of negative on the left and positive on the right, charging the second capacitor, and the current flows through the boost inductor, the freewheeling diode, and the second capacitor in sequence; the first power switch tube and the second power switch tube work alternately, and when the second power switch tube is turned on, the boost inductor is charged again, and the current flows through one end of the first capacitor, the boost inductor, the second power switch tube, and the other end of the first capacitor in sequence; when the second power switch tube is turned off, the boost inductor is discharged.