Single-chip microcomputer regulated flyback power supply circuit for electric spark auxiliary milling

Abstract

The flyback power supply circuit comprises an input unit, an MOS (Metal Oxide Semiconductor) tube control unit, an output unit, a boosting unit, a DC-DC (Direct Current-Direct Current) unit, a single chip microcomputer control unit, a screen unit, a key detection unit and a short-circuit discharge unit, the input unit is connected with the MOS tube control unit to realize voltage reduction of the flyback power supply transformer under the matching action; most of the energy is transmitted to the output unit connected with the power supply; charging and discharging of the capacitor bank are matched with a workpiece to generate electric sparks. The DC-DC unit is connected with the MOS tube control unit through the boost unit and supplies power to the MOS tube control unit in a boost The single-chip microcomputer control unit is powered by a DC-DC unit and is externally connected with a screen unit, a key detection unit and a short-circuit discharge unit. The screen unit is used for displaying discharge voltage and current values; the key detection unit is responsible for adjusting the output end voltage; and the short-circuit discharge unit ensures that the capacitor bank is short-circuited to normally charge and discharge. Various experimental working conditions and safety protection are provided for electric spark auxiliary milling.

Description

Technical Field

[0001] This invention generally relates to the field of auxiliary milling technology, and more specifically, to a flyback power supply circuit for single-chip microcomputer-controlled electrical discharge-assisted milling. Background Technology

[0002] With the rapid development of electronic technology, flyback power supplies have been widely used in numerous electronic devices due to their simple structure, low cost, and ability to achieve electrical isolation. These include common consumer electronics such as mobile phone chargers and tablet power adapters, as well as various small power modules in industrial control. Among the applications of flyback power supplies, there are scenarios requiring the machining of difficult-to-machine materials, especially in electrical discharge milling. This process necessitates generating electrical sparks when the cutting tool cuts difficult-to-machine materials such as nickel-based alloys, demanding higher stability, reliability, and dynamic response capabilities from the power supply system.

[0003] Currently, flyback power supplies, as the core energy supply for EDM (Electrical Discharge Machining), still have shortcomings in areas such as frequent abnormal discharge states and intelligent closed-loop control. For example, Chinese Patent Publication No. CN106513877A discloses a method for controlling the gap of electrical pulse spark discharge. This method aims to maintain the spark discharge state and avoid short circuits, indirectly confirming that short circuits are a common problem that interferes with stable machining and affects efficiency. Another example is Chinese Patent Publication No. CN120460824A, which discloses a high-efficiency precision machining equipment and method for multiple discharges of milling cutters. This method aims to achieve monitoring and control of the machining process, reflecting the industry's urgent need to improve process monitoring and intelligent control capabilities. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, this application provides a flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling with low cost, simple circuitry, good adjustability and adaptability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a flyback power supply circuit for EDM-assisted milling controlled by a microcontroller includes an input unit, a MOSFET control unit, an output unit, a boost unit, a DC-DC unit, a microcontroller control unit, a screen unit, a button detection unit, and a short-circuit discharge unit; the input unit is connected to both the output unit and the MOSFET control unit, the DC-DC unit is connected to the MOSFET control unit through the boost unit to boost its power supply, the microcontroller control unit is connected to the DC-DC unit for power supply, and is externally connected to the screen unit, the button detection unit, and the short-circuit discharge unit.

[0006] Furthermore, the input unit includes a fuse, a rectifier bridge, an anti-backflow diode, and a flyback transformer; one terminal of the fuse is connected to the input neutral line, and the other terminal is connected to the second terminal of the rectifier bridge. The second and third terminals of the rectifier bridge are connected to the input terminal, and the first and fourth terminals are connected to the sixth terminal at the upper end of the flyback transformer. The positive terminal of the anti-backflow diode is connected to the MOSFET control unit, and the negative terminal is connected to the filter circuit at the input terminal of the flyback transformer. The flyback transformer is connected to the MOSFET control unit via its primary side.

[0007] Furthermore, the MOS transistor control unit includes an NMOS flyback switch, an NPN driver transistor, a PNP driver transistor, an optocoupler, an isolation capacitor, and a current detection chip. The first control terminal of the NMOS flyback switch is connected to the second control terminals of the NPN and PNP driver transistors, and the second control terminal is connected to the primary side of the flyback transformer. The first control terminal of the NPN driver transistor is connected to the fourth connection terminal of the optocoupler, and the third control terminal is connected to the output terminal of the boost unit. The second control terminal is connected to the second control terminal of the PNP driver transistor, and the second control terminal of the PNP driver transistor is connected to the NMOS flyback switch. The second control terminal of the PN driving transistor is connected, the third control terminal is grounded, the first control terminal is connected to the fourth connection terminal of the optocoupler, the first connection terminal of the optocoupler is connected to the twenty-ninth connection terminal of the microcontroller control unit, the fourth connection terminal is connected to the first control terminals of the NPN driving transistor and the PNP driving transistor, the second connection terminal and the third connection terminal are grounded and power ground respectively, one connection terminal of the isolation capacitor is connected to power ground, and the other connection terminal is connected to ground, the first connection terminal and the second connection terminal of the current detection chip are connected to the NMOS flyback switch, and the seventh connection terminal is connected to the microcontroller control unit through several capacitors and resistors.

[0008] Furthermore, the output unit includes a rectifier diode, a voltage divider resistor, a voltage detection chip, a first discharge capacitor, a second discharge capacitor, a first absorption peak capacitor, a second absorption peak capacitor, a third absorption peak capacitor, a fourth absorption peak capacitor, a fifth absorption peak capacitor, a sixth absorption peak capacitor, a seventh absorption peak capacitor, and a rotary switch; the rectifier diode is connected to the output terminal of the flyback transformer, one end of the voltage divider resistor is connected to ground, and the other end is connected to the voltage detection chip, the voltage detection chip is connected to the voltage divider resistor and several capacitors and resistors, and the first discharge capacitor and the second discharge capacitor are connected in parallel to the output terminal of the flyback transformer. One connection terminal is connected to the output rectified circuit, and the other connection terminal is grounded. The first, second, third, fourth, fifth, sixth, and seventh absorption peak capacitors are independently connected in parallel across the output port. One connection terminal of the rotary switch is connected to the output circuit through a current-limiting resistor, and the other connection terminal is connected to the first, second, third, fourth, fifth, sixth, and seventh absorption peak capacitors respectively via seven terminals.

[0009] Furthermore, the boost unit includes an isolated power supply module; the input side of the isolated power supply module is connected to the input side of the DC-DC unit, and the output side is connected to the NPN driver transistor.

[0010] Furthermore, the DC-DC unit includes a USB connector and a voltage regulator chip; the USB connector is connected to several capacitors and resistors, and its surface is grounded; the voltage regulator chip is connected to several capacitors and resistors; and a third connection terminal is connected to the USB connector.

[0011] Furthermore, the microcontroller control unit includes an STM32F103C8T6 microcontroller chip and a programming port; the STM32F103C8T6 microcontroller chip is connected to several capacitors, resistors, crystal oscillators, and multiple unit circuits; the fourth connection terminal of the programming port is connected to the DC-DC unit, the second and third connection terminals are connected to the microcontroller control unit, and the first connection terminal is grounded.

[0012] Furthermore, the screen unit includes an OLED display screen; the OLED display screen is connected to several capacitors and resistors to filter the current provided by the DC-DC unit, and the third and fourth connection terminals are both connected to the microcontroller control unit.

[0013] Furthermore, the button detection unit includes a first button and a second button; the first button is connected to the twenty-sixth connection terminal of the microcontroller control unit, and the second button is connected to the twenty-fifth connection terminal of the microcontroller control unit.

[0014] Furthermore, the short-circuit discharge unit includes a high-frequency NMOS switch and a protection resistor; the first control terminal of the high-frequency NMOS switch is connected to the microcontroller control unit and is connected in parallel across the first, second, third, fourth, fifth, sixth, and seventh absorption spike capacitors; one terminal of the protection resistor is grounded, and the other terminal is connected to the first control terminal of the high-frequency NMOS switch.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention includes an input unit, a MOSFET control unit, an output unit, a boost unit, a DC-DC unit, a microcontroller control unit, a screen unit, a button detection unit, and a short-circuit discharge unit. The input unit, connected to the MOSFET control unit, works in conjunction with the flyback power transformer to step down the voltage. Most of the energy is transferred to the connected output unit; the charging and discharging of its capacitor bank interacts with the workpiece to generate an electrical spark. The DC-DC unit, connected to the MOSFET control unit via the boost unit, provides boost power. The microcontroller control unit, powered by the DC-DC unit, is externally connected to the screen unit, button detection unit, and short-circuit discharge unit. The screen unit displays the discharge voltage and current values. The button detection unit adjusts the output voltage. The short-circuit discharge unit ensures the capacitor bank can charge and discharge normally even when short-circuited. This invention provides various experimental working conditions and safety protections for electrical discharge-assisted milling.

[0016] The short-circuit discharge unit includes a high-frequency NMOS switch and a protection resistor. The first control terminal of the high-frequency NMOS switch is connected to the microcontroller control unit and is connected in parallel across the first, second, third, fourth, fifth, sixth, and seventh absorption peak capacitors. When the workpiece is working, the current detection chip detects the output current. When the output current is abnormally high and lasts for a long time, the microcontroller program automatically determines that a short circuit has occurred and disconnects the high-frequency NMOS switch. At this time, the circuit stops discharging. One connection terminal of the protection resistor is grounded, and the other connection terminal is connected to the first control terminal of the high-frequency NMOS switch to prevent the output voltage from being directly applied to the high-frequency NMOS switch, which could cause a high voltage difference and damage the device.

[0017] The first, second, third, fourth, fifth, sixth, and seventh peak absorption capacitors are connected independently in parallel across the output port. They absorb abnormal voltage spikes during work to ensure stable voltage output. Each capacitor has a different capacitance value, providing a wide selection range. When a larger output voltage is required, a larger capacitance value can be selected to absorb abnormal spikes, while when a smaller output voltage is required, a smaller capacitance value can be selected to absorb abnormal spikes. This avoids damaging the workpiece and reducing work efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The circuit schematic diagram of the present invention is provided for an embodiment of the present invention.

[0020] Figure 2 The circuit schematic diagram of the input unit provided by the present invention.

[0021] Figure 3 The circuit schematic diagram of the MOS transistor control unit provided by the present invention.

[0022] Figure 4 The circuit schematic diagram of the output unit provided by the present invention. Figure 5 The circuit diagram of the boost unit provided by the present invention.

[0023] Figure 6 The circuit schematic diagram of the DC-DC unit provided by the present invention.

[0024] Figure 7 The circuit schematic diagram of the microcontroller control unit provided by this invention.

[0025] Figure 8 The circuit schematic diagram of the screen unit provided by the present invention.

[0026] Figure 9 The circuit diagram of the key detection unit provided by the present invention.

[0027] Figure 10 The circuit diagram of the short-circuit discharge unit provided by the present invention. Detailed Implementation

[0028] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] like Figure 1-10 As shown, it includes an input unit 1, a MOSFET control unit 2, an output unit 3, a boost unit 4, a DC-DC unit 5, a microcontroller control unit 6, a screen unit 7, a button detection unit 8, and a short-circuit discharge unit 9. The input unit 1 is connected to both the output unit 3 and the MOSFET control unit 2. The DC-DC unit 5 is connected to the MOSFET control unit 2 through the boost unit 4 to boost its power supply. The microcontroller control unit 6 is powered by the DC-DC unit 5 and is externally connected to the screen unit 7, the button detection unit 8, and the short-circuit discharge unit 9.

[0030] The input unit 1 includes a fuse 11, a rectifier bridge 12, an anti-backflow diode 13, and a flyback transformer 14.

[0031] One connection terminal of the fuse 11 is connected to the input neutral line, and the other connection terminal is connected to the second connection terminal of the rectifier bridge 12 to prevent excessive current in the input unit 1 from damaging the device.

[0032] The second and third connection terminals of the rectifier bridge 12 are connected to the input terminal, and the first and fourth connection terminals are connected to the sixth connection terminal at the upper end of the flyback transformer 14. The alternating current is converted into direct current by switching the internal diodes on and off.

[0033] The positive terminal of the anti-backflow diode 13 is connected to the MOS transistor control unit 2, and the negative terminal is connected to the filter circuit of the input terminal of the flyback transformer 14, which can prevent the current flowing from the MOS transistor control unit 2 to the input terminal through the diode from flowing back.

[0034] The flyback transformer 14 steps down the high voltage generated by the pulsed DC excitation from the MOS transistor control unit 2 connected to the primary side to the expected voltage value.

[0035] The MOS transistor control unit 2 includes an NMOS flyback switch 21, an NPN driver transistor 22, a PNP driver transistor 23, an optocoupler 24, an isolation capacitor 25, and a current detection chip 26.

[0036] The first control terminal of the NMOS flyback switch 21 is connected to the second control terminals of the NPN driver transistor 22 and the PNP driver transistor 23. The second control terminal is connected to the primary side of the flyback transformer 14. When the NPN driver transistor 22 is turned on, it provides current to the NMOS flyback switch 21. When the PNP driver transistor 23 is turned on, the current can flow to ground for discharge. The two work alternately to realize signal amplification and driving.

[0037] The first control terminal of the NPN driving transistor 22 is connected to the fourth connection terminal of the optocoupler 24, the third control terminal is connected to the output terminal of the boost unit 4, and the second control terminal is connected to the second control terminal of the PNP driving transistor 23. After the NPN driving transistor 22 is turned on, the second control terminal provides current to the subsequent circuit.

[0038] The second control terminal of the PNP driving transistor 23 is connected to the second control terminal of the NPN driving transistor 22, the third control terminal is grounded, and the first control terminal is connected to the fourth connection terminal of the optocoupler 24. After the PNP driving transistor 23 is turned on, the current provided by the NPN driving transistor 22 is discharged through the grounded third control terminal of the PNP driving transistor 23.

[0039] The first connection terminal of the optocoupler 24 is connected to the twenty-ninth connection terminal of the microcontroller control unit 6, the fourth connection terminal is connected to the first control terminal of the NPN driving transistor 22 and the PNP driving transistor 23, the second connection terminal and the third connection terminal are grounded and power ground respectively, and the optocoupler 24 is used to control the NMOS flyback switch 21 to cut off the electrical connection between the right side and the left side.

[0040] One terminal of the isolation capacitor 25 is connected to the power ground, and the other terminal is connected to ground, isolating the connection between the two grounds and preventing damage to the device caused by direct connection between the two grounds.

[0041] The first and second connection terminals of the current detection chip 26 are connected to the NMOS flyback switch 21, and the seventh connection terminal is connected to the microcontroller control unit 6 through several capacitors and resistors. The detected current magnitude is fed back to the microcontroller chip and displayed on the OLED display screen 71.

[0042] The output unit 3 includes a rectifier diode 31, a voltage divider resistor 32, a voltage detection chip 33, a first discharge capacitor 34, a second discharge capacitor 34, a first absorption peak capacitor 36, a second absorption peak capacitor 37, a third absorption peak capacitor 38, a fourth absorption peak capacitor 39, a fifth absorption peak capacitor 310, a sixth absorption peak capacitor 311, a seventh absorption peak capacitor 312, and a rotary switch 313.

[0043] The rectifier diode 31 is connected to the output terminal of the flyback transformer 14 to rectify the output AC power into DC power.

[0044] One end of the voltage divider resistor 32 is connected to ground, and the other end is connected to the voltage detection chip 33. The voltage divided is the same as the output voltage, which makes it easy for the voltage detection chip 33 to detect the output voltage.

[0045] The voltage detection chip 33 is connected to the voltage divider resistor 32 and several capacitors and resistors, and detects the output voltage and displays it on the display screen of the screen unit 7.

[0046] The first discharge capacitor 34 and the second discharge capacitor 34 are connected in parallel at the output terminal of the flyback transformer 14. One connection terminal is connected to the output rectified circuit, and the other connection terminal is grounded. The output voltage charges the capacitors, and the stored charge is released when the workpiece is working.

[0047] One end of the first peak-absorbing capacitor 36, the second peak-absorbing capacitor 37, the third peak-absorbing capacitor 38, the fourth peak-absorbing capacitor 39, the fifth peak-absorbing capacitor 310, the sixth peak-absorbing capacitor 311, and the seventh peak-absorbing capacitor 312 are connected to the rotary switch 313, and the other end is grounded. They are connected independently in parallel across the output port. When the workpiece is working, they absorb abnormal voltage spikes to ensure stable voltage output. Each capacitor has a different capacitance value, which provides a wide selection range. When the required output voltage is large, a capacitor with a larger capacitance value can be selected to absorb abnormal spikes. When the required output voltage is small, a capacitor with a smaller capacitance value can be selected to absorb abnormal spikes, which can avoid damaging the workpiece and reducing work efficiency.

[0048] One connection terminal of the rotary switch 313 is connected to the output circuit through a current-limiting resistor, and the other connection terminal is connected to the first peak absorption capacitor 36, the second peak absorption capacitor 37, the third peak absorption capacitor 38, the fourth peak absorption capacitor 39, the fifth peak absorption capacitor 310, the sixth peak absorption capacitor 311, and the seventh peak absorption capacitor 312 by seven terminals respectively, and they are independent of each other. By rotating the switch, an appropriate capacitor size can be selected to absorb abnormal voltage spikes.

[0049] The boost unit 4 includes an isolated power supply module 41.

[0050] The input side of the isolated power supply module 41 is connected to the input side of the DC-DC unit 5, and the output side is connected to the NPN driver transistor 22 to provide a suitable voltage for the subsequent circuit.

[0051] The DC-DC unit 5 includes a USB connector 51 and a voltage regulator chip 52.

[0052] The USB connector 51 is connected to several capacitors and resistors, its surface is grounded, and a fixed voltage is input to the input terminal to power the boost unit 4 and the voltage regulator chip 52.

[0053] The voltage regulator chip 52 is connected to several capacitors and resistors, and the third connection terminal is connected to the USB connector 51 to provide a fixed voltage to the chip. The output terminal outputs the expected voltage to power multiple unit circuits.

[0054] The microcontroller control unit 6 includes an STM32F103C8T6 microcontroller chip 61 and a programmable port 62.

[0055] The STM32F103C8T6 microcontroller chip 61 is connected to several capacitors, resistors, crystal oscillators, and multiple unit circuits. Through program control, it detects the magnitude of the output voltage and current, as well as the magnitude of the PWM signal sent to the MOS transistor control unit 2, so as to realize the adjustable output voltage to adapt to various working environments.

[0056] The fourth connection terminal of the program burning port 62 is connected to the DC-DC unit 5, the second and third connection terminals are connected to the microcontroller control unit 6, and the first connection terminal is grounded for burning programs.

[0057] The screen unit 7 includes an OLED display screen 71.

[0058] The OLED display screen 71 is connected to several capacitors and resistors to filter the current provided by the DC-DC unit 5. The third and fourth connection terminals are both connected to the microcontroller control unit 6 to display the detected target parameters.

[0059] The button detection unit 8 includes a first button 81 and a second button 82.

[0060] The first button 81 is connected to the twenty-sixth connection terminal of the microcontroller control unit 6. Pressing and holding the first button 81 increases the target output voltage, and double-clicking drives the microcontroller control unit 6 to send a PWM signal.

[0061] The second button 82 is connected to the twenty-fifth connection terminal of the microcontroller control unit 6. Pressing and holding the second button 82 reduces the target output voltage, and double-clicking stops the microcontroller control unit 6 from sending PWM signals.

[0062] The short-circuit discharge unit 9 includes a high-frequency NMOS switch 91 and a protection resistor 92.

[0063] The first control terminal of the high-frequency NMOS switch 91 is connected to the microcontroller control unit 6 and is connected in parallel across the first absorption peak capacitor 36, the second absorption peak capacitor 37, the third absorption peak capacitor 38, the fourth absorption peak capacitor 39, the fifth absorption peak capacitor 310, the sixth absorption peak capacitor 311, and the seventh absorption peak capacitor 312. When the workpiece is working, the current detection chip 26 detects the output current. When the output current is abnormally large and lasts for a long time, the microcontroller program automatically determines that the circuit has short-circuited and disconnects the high-frequency NMOS switch 91. At this time, the circuit stops discharging.

[0064] One terminal of the protection resistor 92 is grounded, and the other terminal is connected to the first control terminal of the high-frequency NMOS switch 91.

[0065] The method of using this invention is as follows: When the invention starts working, the voltage is rectified by the rectifier bridge 12 of the input unit 1 and transmitted to the sixth connection terminal of the flyback transformer 14. The first connection terminal of the flyback transformer 14 is connected to the MOS transistor control unit 2. After the NPN drive transistor 22 of the MOS transistor control unit 2 is turned on by the input voltage of the boost unit 4, its second control terminal provides current to the subsequent circuit. At the same time, the PNP drive transistor 23 is also turned on. Then, the current provided by the NPN drive transistor 22 is discharged to ground through the third control terminal of the PNP drive transistor 23. The first connection terminal of the optocoupler 24 transmits the PWM signal sent by the microcontroller control unit 6 to control the on and off of the NMOS flyback switch 21 and send pulsed DC to the flyback transformer 14. The voltage after rectification at the sixth connection terminal of the flyback transformer 14, combined with the pulsed DC signal sent by the MOSFET control unit 2, achieves voltage reduction of the flyback power transformer 14. Most of the energy at the output terminal of the flyback transformer 14 is transferred to the connected output unit 3. The charging and discharging action of the first and second discharge capacitors 34 in the output unit 3, in conjunction with the workpiece, generates an electric spark. Simultaneously, one end of each of the following capacitors—the first absorption spike capacitor 36, the second absorption spike capacitor 37, the third absorption spike capacitor 38, the fourth absorption spike capacitor 39, the fifth absorption spike capacitor 310, the sixth absorption spike capacitor 311, and the seventh absorption spike capacitor 312—is connected to the rotary switch 313, and the other end is grounded. They are independently connected in parallel across the output port. During operation, the capacitors absorb abnormal voltage spikes to ensure stable voltage output. Each capacitor has a different capacitance value, offering a wide selection range. When a larger output voltage is required, a larger capacitance value can be selected to absorb abnormal spikes; when a smaller output voltage is required, a smaller capacitance value can be selected. This prevents damage to the workpiece and reduces work efficiency. The DC-DC unit 5 receives voltage from the USB connector 51, and then connects to the MOSFET control unit 2 via the boost unit 4 to boost its power. The microcontroller control unit 6 is powered by the output port of the DC-DC unit 5 and is externally connected to the screen unit 7, button detection unit 8, and short-circuit discharge unit 9. The microcontroller control unit 6 processes the information fed back from the current detection chip 26, voltage detection chip 33, and short-circuit discharge unit 9. After processing, the data is displayed on the OLED display screen 71. The screen unit 7 displays the discharge voltage, current values, and the pulse width ratio of the PWM signal sent by the microcontroller control unit 6 to the MOS transistor control unit 2. The button detection unit 8 adjusts the output voltage and controls the start and stop of the circuit through different operation modes of the first button 81 and the second button 82. The short-circuit discharge unit 9 is connected in parallel across the first absorption peak capacitor 36, the second absorption peak capacitor 37, the third absorption peak capacitor 38, the fourth absorption peak capacitor 39, the fifth absorption peak capacitor 310, the sixth absorption peak capacitor 311, and the seventh absorption peak capacitor 312. When the workpiece is working, the current detection chip 26 detects the output current. When the output current is abnormally high and lasts for a long time,The microcontroller program automatically detects a short circuit and disconnects the high-frequency NMOS switch 91. At this point, the circuit stops discharging, protecting the system.

[0066] The above is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A flyback power supply circuit for EDM-assisted milling controlled by a microcontroller, comprising an input unit (1), a MOS transistor control unit (2), an output unit (3), a boost unit (4), a DC-DC unit (5), a microcontroller control unit (6), a screen unit (7), a button detection unit (8), and a short-circuit discharge unit (9); the input unit (1) is connected to both the output unit (3) and the MOS transistor control unit (2), the DC-DC unit (5) is connected to the MOS transistor control unit (2) through the boost unit (4) to boost its power supply, the microcontroller control unit (6) is connected to the DC-DC unit (5) for power supply, and is externally connected to the screen unit (7), the button detection unit (8), and the short-circuit discharge unit (9).

2. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The input unit (1) includes a fuse (11), a rectifier bridge (12), an anti-backflow diode (13), and a flyback transformer (14). One connection terminal of the fuse (11) is connected to the input neutral line, and the other connection terminal is connected to the second connection terminal of the rectifier bridge (12) to prevent the input unit (1) from being damaged by excessive current; The second and third connection terminals of the rectifier bridge (12) are connected to the input terminal, and the first and fourth connection terminals are connected to the sixth connection terminal at the upper end of the flyback transformer (14). The alternating current is converted into direct current by switching the internal diodes on and off. The positive terminal of the anti-backflow diode (13) is connected to the MOS transistor control unit (2), and the negative terminal is connected to the filter circuit of the input terminal of the flyback transformer (14), which can prevent the current flowing from the MOS transistor control unit (2) to the input terminal through the diode from flowing back; The flyback transformer (14) is stepped down to the expected voltage value by the high voltage generated by the pulse DC excited by the MOS transistor control unit (2) connected to the primary side.

3. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The MOS transistor control unit (2) includes an NMOS flyback switch (21), an NPN driver transistor (22), a PNP driver transistor (23), an optocoupler (24), an isolation capacitor (25), and a current detection chip (26). The first control terminal of the NMOS flyback switch (21) is connected to the second control terminals of the NPN drive transistor (22) and the PNP drive transistor (23). The second control terminal is connected to the primary side of the flyback transformer (14). When the NPN drive transistor (22) is turned on, it provides current to the NMOS flyback switch (21). When the PNP drive transistor (23) is turned on, the current can flow to ground for discharge. The two work alternately to realize signal amplification and driving. The first control terminal of the NPN driving transistor (22) is connected to the fourth connection terminal of the optocoupler (24), the third control terminal is connected to the output terminal of the boost unit (4), and the second control terminal is connected to the second control terminal of the PNP driving transistor (23). After the NPN driving transistor (22) is turned on, the second control terminal provides current to the subsequent circuit. The second control terminal of the PNP driving transistor (23) is connected to the second control terminal of the NPN driving transistor (22), the third control terminal is grounded, the first control terminal is connected to the fourth connection terminal of the optocoupler (24), and the current provided by the NPN driving transistor (22) after the PNP driving transistor (23) is turned on is discharged through the ground of the third control terminal of the PNP driving transistor (23). The first connection terminal of the optocoupler (24) is connected to the twenty-ninth connection terminal of the single-chip microcomputer control unit (6), the fourth connection terminal is connected to the first control terminal of the NPN driving transistor (22) and the PNP driving transistor (23), the second connection terminal and the third connection terminal are grounded and power ground respectively, and the optocoupler (24) is used to control the NMOS flyback switch (21) to cut off the electrical connection between the right side and the left side; One terminal of the isolation capacitor (25) is connected to the power ground, and the other terminal is connected to ground, isolating the connection between the two grounds and preventing direct connection between the two grounds from causing damage to the device; The first and second connection terminals of the current detection chip (26) are connected to the NMOS flyback switch (21), and the seventh connection terminal is connected to the microcontroller control unit (6) through several capacitors and resistors. The detected current magnitude is fed back to the microcontroller chip and displayed on the OLED display screen (71).

4. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The output unit (3) includes a rectifier diode (31), a voltage divider resistor (32), a voltage detection chip (33), a first discharge capacitor (34), a second discharge capacitor (35), a first absorption peak capacitor (36), a second absorption peak capacitor (37), a third absorption peak capacitor (38), a fourth absorption peak capacitor (39), a fifth absorption peak capacitor (310), a sixth absorption peak capacitor (311), a seventh absorption peak capacitor (312), and a rotary switch (313). The rectifier diode (31) is connected to the output terminal of the flyback transformer (14) to rectify the output AC power into DC power; One end of the voltage divider resistor (32) is connected to ground, and the other end is connected to the voltage detection chip (33). The voltage divided is the same as the output voltage, which makes it easier for the voltage detection chip (33) to detect the output voltage. The voltage detection chip (33) is connected to the voltage divider resistor (32) and several capacitors and resistors to detect the output voltage and display it on the display screen of the screen unit (7); The first discharge capacitor (34) and the second discharge capacitor (35) are connected in parallel at the output terminal of the flyback transformer (14). One connection terminal is connected to the rectified output circuit, and the other connection terminal is grounded. The output voltage charges the capacitor and releases the stored charge when the workpiece is working. The first peak absorption capacitor (36), the second peak absorption capacitor (37), the third peak absorption capacitor (38), the fourth peak absorption capacitor (39), the fifth peak absorption capacitor (310), the sixth peak absorption capacitor (311), and the seventh peak absorption capacitor (312) are connected in parallel to each other at both ends of the output port to absorb abnormal voltage spikes when the workpiece is working and ensure stable voltage output. One connection terminal of the rotary switch (313) is connected to the output circuit through a current-limiting resistor, and the other connection terminal is connected to the first peak absorption capacitor (36), the second peak absorption capacitor (37), the third peak absorption capacitor (38), the fourth peak absorption capacitor (39), the fifth peak absorption capacitor (310), the sixth peak absorption capacitor (311), and the seventh peak absorption capacitor (312) by seven terminals respectively, and they are independent of each other. By rotating the switch, a capacitor of appropriate size can be selected to absorb abnormal voltage spikes.

5. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The boost unit (4) includes an isolated power supply module (41). The input side of the isolated power supply module (41) is connected to the input side of the DC-DC unit (5), and the output side is connected to the NPN driving transistor (22) to provide a suitable voltage for the subsequent circuit.

6. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The DC-DC unit (5) includes a USB connector (51) and a voltage regulator chip (52). The USB connector (51) is connected to several capacitors and resistors, its surface is grounded, and a fixed voltage is input at the input terminal to power the boost unit (4) and the voltage regulator chip (52). The voltage regulator chip (52) is connected to several capacitors and resistors, and the third connection terminal is connected to the USB connector (51) to provide a fixed voltage to the chip. The output terminal outputs the expected voltage to power multiple unit circuits.

7. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The microcontroller control unit (6) includes an STM32F103C8T6 microcontroller chip (61) and a program programming port (62). The STM32F103C8T6 microcontroller chip (61) is connected to several capacitors, resistors, crystal oscillators and multiple unit circuits. The output voltage and current are detected and the PWM signal sent by the MOS transistor control unit (2) are displayed through the program, so as to realize the adjustable output voltage to adapt to various working environments. The fourth connection terminal of the program burning port (62) is connected to the DC-DC unit (5), the second connection terminal and the third connection terminal are connected to the microcontroller control unit (6), and the first connection terminal is grounded for burning programs.

8. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The screen unit (7) includes an OLED display (71); The OLED display screen (71) is connected to several capacitors and resistors to filter the current provided by the DC-DC unit (5). The third and fourth connection terminals are both connected to the microcontroller control unit (6) to display the detected target parameters.

9. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The button detection unit (8) includes a first button (81) and a second button (82); The first button (81) is connected to the twenty-sixth connection terminal of the microcontroller control unit (6). Pressing and holding the first button (81) increases the target output voltage, and double-clicking drives the microcontroller control unit (6) to send a PWM signal. The second button (82) is connected to the twenty-fifth connection terminal of the microcontroller control unit (6). Pressing and holding the second button (82) reduces the target output voltage, and double-clicking stops the microcontroller control unit (6) from sending PWM signals.

10. The flyback power supply circuit for single-chip microcomputer-controlled EDM-assisted milling as described in claim 1, characterized in that, The short-circuit discharge unit (9) includes a high-frequency NMOS switch (91) and a protection resistor (92). The first control terminal of the high-frequency NMOS switch (91) is connected to the single-chip microcomputer control unit (6) and is connected in parallel across the first absorption peak capacitor (36), the second absorption peak capacitor (37), the third absorption peak capacitor (38), the fourth absorption peak capacitor (39), the fifth absorption peak capacitor (310), the sixth absorption peak capacitor (311), and the seventh absorption peak capacitor (312). One terminal of the protection resistor (92) is grounded, and the other terminal is connected to the first control terminal of the high-frequency NMOS switch (91).

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