CN112077406B - Micro-energy pulse power supply for high-speed reciprocating wire-moving electric spark wire cutting processing - Google Patents

Abstract

The invention discloses a micro-energy pulse power supply for high-speed reciprocating wire EDM wire cutting, comprising a main power circuit, a back-voltage circuit, a detection circuit, an FPGA control circuit and a drive circuit, wherein the main power circuit is used for Charge the gap to provide discharge energy; the back-voltage circuit is used to increase the voltage on the line impedance in the electrical discharge machining stage and improve the current drop rate; the detection circuit is used to collect the voltage and current of the gap in real time, and transmit after sampling and conditioning into the FPGA; the FPGA control circuit generates corresponding control signals according to the voltage and current changes in the gap; the drive circuit is used to amplify the control signal, and generate the drive signal to drive the on and off of the switch in the main power circuit. break. The invention adds a back-voltage circuit after the main power circuit, improves the falling slope of the gap current in the process of machining gap discharge, reduces the pulse width of the discharge current, realizes processing with small energy, and improves the surface quality of the finished product.

Description

Micro-energy pulse power supply for high-speed reciprocating wire EDM

technical field

The invention relates to a micro-processing pulse power supply, in particular to a micro-energy pulse power supply used for high-speed reciprocating wire EDM wire cutting.

Background technique

The high-speed reciprocating wire EDM wire EDM processing mode (commonly known as "fast wire EDM") is a unique WEDM processing mode created in my country. Wire”), which has the characteristics of low electrode wire loss and low processing cost. In the field of industrial manufacturing, my country has applied the improvement of the high-speed reciprocating wire EDM processing mode to the actual WEDM process, creating a new processing mode, which mainly adopts the processing of "cutting one and repairing two". The first rough machining and cutting, followed by finishing trimming and micro-energy machining, are also based on the machining method and characteristics of high-speed reciprocating wire EDM. It also has high machining efficiency, high precision, low cost and good surface quality. Etc.

Pulse power supply is an important part of WEDM machine tool, and its performance directly affects processing efficiency, processing accuracy, surface roughness, cutting stability, etc. The circuit topology used by most of the current pulse power supplies has the problems of large discharge pulse width and too high discharge energy in a single cycle in high-speed reciprocating wire EDM wire cutting, especially when using high-speed reciprocating wire EDM The discharge pulse width is maintained at about 1 μs for a long time in the process of trimming the tool in the wire cutting mode, so that the surface quality and accuracy of the workpiece will be low.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a micro-energy pulse power supply for high-speed reciprocating wire EDM wire cutting.

The technical solution to achieve the purpose of the present invention is: a micro-energy pulse power supply for high-speed reciprocating wire EDM wire cutting, including a main power circuit, a back-voltage circuit, a detection circuit, an FPGA control circuit and a drive circuit, wherein the The main power circuit is used to charge the gap and provide discharge energy; the back-voltage circuit is used to increase the voltage on the line impedance in the discharge machining stage, and improve the current drop rate; the detection circuit is used to collect the voltage and current of the gap in real time The FPGA control circuit generates corresponding control signals according to the voltage and current changes of the gaps; the drive circuit is used to amplify the control signals and generate the drive signals to drive the switches in the main power circuit. turn-on and turn-off of the tube.

The main power circuit includes a first DC power supply, a first switch tube, a second switch tube, a first diode, a second diode, a third diode and an inductor, wherein the positive electrode of the first DC power supply It is connected to one end of the first switch tube, the negative pole of the first DC power supply is grounded, the other end of the first switch tube is connected to the inductor, the other end of the inductor is connected to the second switch tube, and the anode of the first diode is connected to the first switch tube. The negative pole of the DC power supply is connected, the cathode of the first diode and the first switch tube are connected to the connection point of the inductor, the anode of the second diode and the inductor are connected to the connection point of the second switch tube, the second two The cathode of the pole tube and the first DC power supply are connected to the connection point of the first switch tube, the anode of the third diode is connected to one end of the second switch tube, and the cathode and inductance of the third diode are connected to the second switch tube. The connection points of the pipes are connected. The connection point of the second switch tube and the anode of the third diode and the cathode of the first DC power supply are respectively connected to both ends of the reverse voltage circuit.

The back-voltage circuit includes a second DC power supply, a resistor, a capacitor, a fourth diode and a fifth diode, wherein one end of the capacitor and the connection point of the second switch tube and the anode of the third diode are connected, and the first The anode of the fifth diode is connected to the negative electrode of the first DC power supply, the cathode of the fifth diode is connected to the other end of the capacitor, one end of the resistor is connected to one end of the capacitor, and the other end of the resistor is connected to the other end of the capacitor. The negative pole of the second DC power supply and the second switch tube are connected to the connection point of the anode of the third diode, the positive pole of the second DC power supply is connected to the anode of the fourth diode, and the cathode and capacitance of the fourth diode are connected to The connection point of the fifth diode is connected, the connection point of the capacitor and the resistor to the negative electrode of the second DC power supply is connected to one end of the line inductance, and the other end of the line inductance and the negative electrode of the first DC power supply are respectively connected to both ends of the gap.

The first switch tube and the second switch tube are made of silicon carbide metal-oxide semiconductor field effect transistor SiCMOSFET, which is made of SiC.

The driving circuit selects a driving chip with high- and low-end dual-channel driving and isolation characteristics.

A processing method based on the above-mentioned micro-energy pulse power supply, comprising the following steps:

Step 1: Before starting processing, control the first switch tube and the second switch tube of the main power circuit to turn off. At this time, the second DC power supply in the reverse voltage circuit charges the capacitor through the fourth diode, and the capacitor on the capacitor is charged. The energy rises until the voltage on the capacitor rises to be equal to the voltage across the second DC power supply;

Step 2: Control the first switch tube and the second switch tube to be turned on. At this time, the first DC power supply in the main power circuit charges the line inductance and the gap. When the gap voltage reaches the breakdown voltage, the gap is broken down and starts perform electrical discharge machining;

Step 3: When the gap current rises to a given peak current, control the first switch tube and the second switch tube to turn off. At this time, the first DC power supply no longer supplies power to the gap, the gap current drops, and the circuit is divided into two parts. In this part, the inductor in the main power circuit feeds back the accumulated energy to the first DC power supply through the second diode; the conduction of the fifth diode in the back-voltage circuit raises the voltage across the line inductor, making the gap current The descending slope increases;

Step 4: After the current discharge is completed, enter between the processing pulses for deionization;

Step 5: Repeat steps 1-4 for the next machining cycle.

A computer device, comprising a memory, a processor and a computer program stored in the memory and running on the processor, the processor implements the following steps when executing the computer program:

Step 1: Before starting processing, control the first switch tube and the second switch tube of the main power circuit to turn off. At this time, the second DC power supply in the reverse voltage circuit charges the capacitor through the fourth diode, and the capacitor on the capacitor is charged. The energy rises until the voltage on the capacitor rises to be equal to the voltage across the second DC power supply;

Step 2: Control the first switch tube and the second switch tube to be turned on. At this time, the first DC power supply in the main power circuit charges the line inductance and the gap. When the gap voltage reaches the breakdown voltage, the gap is broken down and starts perform electrical discharge machining;

Step 3: When the gap current rises to a given peak current, control the first switch tube and the second switch tube to turn off. At this time, the first DC power supply no longer supplies power to the gap, the gap current drops, and the circuit is divided into two parts. In this part, the inductor in the main power circuit feeds back the accumulated energy to the first DC power supply through the second diode; the conduction of the fifth diode in the reverse voltage circuit raises the voltage across the line inductor, making the gap current The descending slope increases;

Step 4: After the current discharge is completed, enter between the processing pulses for deionization;

Step 5: Repeat steps 1-4 for the next machining cycle.

A computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

Step 1: Before starting processing, control the first switch tube and the second switch tube of the main power circuit to turn off. At this time, the second DC power supply in the reverse voltage circuit charges the capacitor through the fourth diode, and the capacitor on the capacitor is charged. The energy rises until the voltage on the capacitor rises to be equal to the voltage across the second DC power supply;

Step 2: Control the first switch tube and the second switch tube to be turned on. At this time, the first DC power supply in the main power circuit charges the line inductance and the gap. When the gap voltage reaches the breakdown voltage, the gap is broken down and starts perform electrical discharge machining;

Step 3: When the gap current rises to a given peak current, control the first switch tube and the second switch tube to turn off. At this time, the first DC power supply no longer supplies power to the gap, the gap current drops, and the circuit is divided into two parts. In this part, the inductor in the main power circuit feeds back the accumulated energy to the first DC power supply through the second diode; the conduction of the fifth diode in the back-voltage circuit raises the voltage across the line inductor, making the gap current The descending slope increases;

Step 4: After the current discharge is completed, enter between the processing pulses for deionization;

Step 5: Repeat steps 1-4 for the next machining cycle.

Compared with the prior art, the present invention has the following significant advantages: 1) A back-voltage circuit is added after the main power circuit, which improves the falling slope of the gap current during the machining gap discharge process, reduces the discharge current pulse width, and realizes low energy consumption. 2) In the main power circuit, diodes are connected in reverse parallel at both ends of the inductor and the switch tube, which can feed back the energy stored in the inductor to the DC power supply during the processing, improving the Power utilization; 3) The control circuit part adopts FPGA, which can programmatically control the parameters of different processing stages, change the peak current size, and meet the needs of different processing.

Description of drawings

FIG. 1 is a frame diagram of a micro-energy pulse power supply used for high-speed reciprocating wire EDM wire cutting according to the present invention.

FIG. 2 is a circuit topology diagram of a micro-energy pulse power supply used for high-speed reciprocating wire EDM wire cutting according to the present invention.

FIG. 3 is a frame diagram of the detection circuit of the present invention.

FIG. 4 is a schematic diagram of the application of the driver chip of the present invention.

Figure 5 is a schematic diagram of the gap voltage and gap current waveforms in the high-speed reciprocating wire EDM process.

Detailed ways

The solution of the present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in FIG. 1 , the micro-energy pulse power supply used for high-speed reciprocating wire EDM wire cutting according to the present invention includes a main power circuit, a back-voltage circuit, a detection circuit, an FPGA control circuit and a drive circuit, wherein the main power circuit It is used to charge the gap and provide discharge energy; the back-voltage circuit is used to increase the voltage on the line impedance in the discharge machining stage, and to improve the current drop rate; the detection circuit is used to collect the voltage and current of the gap in real time; the FPGA The control circuit generates corresponding control signals according to the voltage and current changes of the gap; the driving circuit is used for amplifying the control signals, and generating the driving signals to drive the switching on and off of the main power circuit.

As shown in FIG. 2 , the topological components of the micro-energy pulse power supply for high-speed reciprocating wire EDM processing include a first DC power supply V ₁ , a second DC power supply V ₂ , a resistor R, a capacitor C, and an inductor L , line inductance L _m , first switch tube Q ₁ , second switch tube Q ₂ , first diode D ₁ , second diode D ₂ , third diode D ₃ , fourth diode D ₄ and the fifth diode D ₅ , wherein the first DC power supply V ₁ , the inductor L, the first switch tube Q ₁ , the second switch tube Q ₂ , the first diode D ₁ , the second diode D ₂ and the third diode D ₃ form the main power circuit, the second DC power supply V ₂ , the resistor R, the capacitor C, the fourth diode D ₄ and the fifth diode D ₅ form the reverse voltage circuit. The positive pole of the _first DC power supply V1 in the main power circuit is connected to _one end of the first switch tube Q1, the negative pole of the _first DC power supply V1 is grounded, and the other end of the _first switch tube Q1 is connected to the inductor L, The other end of the inductor L is connected to the second switch tube Q ₂ , the anode of the first diode D ₁ is connected to the cathode of the first DC power supply V ₁ , and the cathode of the first diode D ₁ is connected to the first switch tube Q ₁ is connected to the connection point of the inductor L, the anode of the second diode D ₂ and the inductor L are connected to the connection point of the second switch tube Q ₂ , and the cathode of the second diode D ₂ is connected to the first DC power supply V1 is connected to the connection point _of the _first switch tube Q1, the anode of the third diode _D3 is connected to one end of the second switch tube _Q2 , and the cathode of the _third diode D3 and the inductance L are connected to the second switch tube Q2. The connection point of the switch tube _Q2 is connected. The connection point between the second switch tube Q ₂ and the anode of the third diode D ₃ and the cathode of the first DC power supply V ₁ are respectively connected to both ends of the reverse voltage circuit.

In the reverse voltage circuit, one end of the capacitor C is connected to the connection point of the second switch tube _Q2 and the anode of the third diode _D3 , and the anode of the _fifth diode D5 is connected to the negative electrode of the _first DC power supply V1. , the cathode of the _fifth diode D5 is connected to the other end of the capacitor C, one end of the resistor R is connected to one end of the capacitor C, the other end of the resistor R is connected to the other end of the capacitor C, and the negative electrode of the _second DC power supply V2 and the connection point of the second switch tube _Q2 and the anode of the third diode _D3 , the anode of the _second DC power supply V2 is connected to the anode of the _fourth diode D4, and the anode of the _fourth diode D4 The cathode and the capacitor C are connected to the connection point of the _fifth diode D5, the connection point of the capacitor C, the resistor R and the negative electrode of the _second DC power supply V2 is connected to one end of the line inductance _Lm , and the other end of the line inductance _Lm and the negative pole of the first DC power supply V ₁ are respectively connected to both ends of the gap.

In addition, there is a line inductance _Lm on the line connecting the back-voltage circuit and the gap. For the convenience of description, the connection point between the capacitor C and the line inductance _Lm is defined as node a, and the connection point between the capacitor C and the negative electrode of the _fifth diode D5 is defined as node a. The node is node b, and the node at the anode of the _fifth diode D5 is node c.

As a specific example, for the switch tube in the circuit topology, a silicon carbide metal-oxide semiconductor field effect transistor (SiC MOSFET) can be selected. Since this circuit topology is mainly used as a pulse power supply for high-speed reciprocating wire EDM, the present invention selects a SiCMOSFET with the model IMW120R090M1H from Infineon, whose drain-source voltage V _DS is as high as 250V, and the drain-source voltage V DS is as high as 250V. The current I _D is 19A, which can be applied to the pulse power supply occasions of high-speed reciprocating wire EDM with high working frequency.

For the detection circuit, it is used to accurately detect and collect the gap current and voltage in real time, and then transfer it to the FPGA control circuit for analysis and drive control after digital-to-analog conversion. Figure 3 shows an example of the detection circuit. After the signal is sampled and conditioned, the gap voltage and the gap current will be converted into a standard measured signal. After passing through the unified interface, the measured signal will pass through the attenuation circuit to conform to the digital-to-analog conversion. The input requirements of the chip, and finally the converted data is transferred to the corresponding interface of the FPGA in parallel.

For the FPGA control circuit, FPGA (ie field programmable gate array) is mainly used for control. Since the corresponding control circuit structure has been integrated inside, the driving signal of the corresponding switch tube can be automatically obtained through program operation, and the program control can be used at the same time. To meet the current needs of different processing stages. As a specific example, the Cyclone IV series chip EP4CE6F17C8 of ALTERA Company can be selected.

For the driver circuit, a driver chip with high- and low-end dual-channel driver and isolation characteristics can be selected. In the present invention, the driver chip of the Texas Instruments (Texas Electronics) company whose model is UCC21520 can be selected. As shown in Figure 4, the chip has The high- and low-end dual-channel driver is an isolated dual-channel gate driver chip, which can be applied to high-frequency switching tubes, and has high stability and high efficiency at the same time.

During the machining process, the main power circuit, back-voltage circuit, detection circuit, FPGA control circuit, and drive circuit in the pulse power supply are combined into a whole, acting on both ends of the workpiece and the tool to control the gap current. The gap current waveform during machining is shown in Figure 5. In the stage of 0～ _t1 , the first DC power supply charges the gap, the voltage on the gap keeps rising, and there is a certain leakage current in the gap; in the stage _t1 ～ _t2 , the gap is broken down, and electrical discharge machining starts, and the gap The voltage drops rapidly from the breakdown voltage to the spark sustaining voltage, and the current rises to a certain peak current at a certain slope; in the t ₂ ~ t ₃ stage, the pulse voltage is turned off, and as the pulse voltage drops to zero, the pulse current also decreases. It quickly drops to zero, and the existence of the back-voltage circuit makes the pulse current drop faster; after time _t3 , it enters the deionization stage until the end of one processing cycle.

Based on the above processing method of micro-energy pulse power supply, the specific process is as follows:

Step 1: Before starting processing, control the first switch tube and the second switch tube of the main power circuit to turn off. At this time, the second DC power supply in the reverse voltage circuit charges the capacitor through the fourth diode, and the capacitor on the capacitor is charged. The energy rises until the voltage on the capacitor rises to be equal to the voltage across the second DC power supply;

Step 2: Control the first switch tube and the second switch tube to be turned on. At this time, the first DC power supply in the main power circuit charges the line inductance and the gap. When the gap voltage reaches the breakdown voltage, the gap is broken down and starts perform electrical discharge machining;

Step 3: When the gap current rises to a given peak current, control the first switch tube and the second switch tube to turn off. At this time, the first DC power supply no longer supplies power to the gap, the gap current drops, and the circuit is divided into two parts. In this part, the inductor in the main power circuit feeds back the accumulated energy to the first DC power supply through the second diode; the conduction of the fifth diode in the reverse voltage circuit raises the voltage across the line inductor, making the gap current The descending slope increases;

Step 4: After the current discharge is completed, enter between the processing pulses for deionization;

Step 5: Repeat steps 1-4 for the next machining cycle.

The present invention also proposes a computer device, comprising a memory, a processor, and a computer program stored on the memory and running on the processor, wherein the processor implements the following steps when executing the computer program:

Step 1: Before starting processing, control the first switch tube and the second switch tube of the main power circuit to turn off. At this time, the second DC power supply in the reverse voltage circuit charges the capacitor through the fourth diode, and the capacitor on the capacitor is charged. The energy rises until the voltage on the capacitor rises to be equal to the voltage across the second DC power supply;

Step 2: Control the first switch tube and the second switch tube to be turned on. At this time, the first DC power supply in the main power circuit charges the line inductance and the gap. When the gap voltage reaches the breakdown voltage, the gap is broken down and starts perform electrical discharge machining;

Step 3: When the gap current rises to a given peak current, control the first switch tube and the second switch tube to turn off. At this time, the first DC power supply no longer supplies power to the gap, the gap current drops, and the circuit is divided into two parts. In this part, the inductor in the main power circuit feeds back the accumulated energy to the first DC power supply through the second diode; the conduction of the fifth diode in the back-voltage circuit raises the voltage across the line inductor, making the gap current The descending slope increases;

Step 4: After the current discharge is completed, enter between the processing pulses for deionization;

Step 5: Repeat steps 1-4 for the next machining cycle.

A computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

Step 1: Before starting processing, control the first switch tube and the second switch tube of the main power circuit to turn off. At this time, the second DC power supply in the reverse voltage circuit charges the capacitor through the fourth diode, and the capacitor on the capacitor is charged. The energy rises until the voltage on the capacitor rises to be equal to the voltage across the second DC power supply;

Step 2: Control the first switch tube and the second switch tube to be turned on. At this time, the first DC power supply in the main power circuit charges the line inductance and the gap. When the gap voltage reaches the breakdown voltage, the gap is broken down and starts perform electrical discharge machining;

Step 3: When the gap current rises to a given peak current, control the first switch tube and the second switch tube to turn off. At this time, the first DC power supply no longer supplies power to the gap, the gap current drops, and the circuit is divided into two parts. In this part, the inductor in the main power circuit feeds back the accumulated energy to the first DC power supply through the second diode; the conduction of the fifth diode in the back-voltage circuit raises the voltage across the line inductor, making the gap current The descending slope increases;

Step 4: After the current discharge is completed, enter between the processing pulses for deionization;

Step 5: Repeat steps 1-4 for the next machining cycle.

The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, all It is considered to be the range described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims (7)

1. A micro-energy pulse power supply for high-speed reciprocating wire-moving electric spark wire cutting machining is characterized by comprising a main power circuit, a counter-voltage circuit, a detection circuit, an FPGA control circuit and a driving circuit, wherein the main power circuit is used for charging a gap and providing discharge energy; the back-pressure circuit is used for increasing the voltage on the line impedance in the discharge machining stage and improving the current reduction rate; the detection circuit is used for acquiring voltage and current of the gap in real time, sampling and conditioning the voltage and current and transmitting the sampled and conditioned voltage and current to the FPGA; the FPGA control circuit generates corresponding control signals according to the voltage and current changes of the gap; the driving circuit is used for amplifying the control signal and generating a driving signal to drive the switch tube in the main power circuit to be switched on and off;

The main power circuit comprises a first direct current power supply (V)₁) A first switch tube (Q)₁) A second switch tube (Q)₂) A first diode (D)₁) A second diode (D)₂) And a third diode (D)₃) And an inductance (L), wherein the first direct current source (V)₁) Positive electrode and first switching tube (Q)₁) ToEnd-connected, first direct current source (V)₁) Is grounded, the first switching tube (Q)₁) Is connected with an inductor (L), and the other end of the inductor (L) is connected with a second switch tube (Q)₂) Connected, a first diode (D)₁) And a first direct current power supply (V)₁) Is connected to the negative pole of the first diode (D)₁) And a first switching tube (Q)₁) A second diode (D) connected to the junction of the inductor (L)₂) And an inductor (L) and a second switching tube (Q)₂) Is connected to the connection point of a second diode (D)₂) And a first direct current power supply (V)₁) And a first switch tube (Q)₁) Is connected to the connection point of the third diode (D)₃) And a second switching tube (Q)₂) Is connected to one terminal of a third diode (D)₃) And a second switch tube (Q) and an inductor (L)₂) Is connected to the second switching tube (Q)₂) And a third diode (D)₃) And a first direct current power supply (V)₁) Respectively connected to both ends of the counter voltage circuit.

2. Micro-energy pulse power supply for high-speed reciprocating wire-cut electrical discharge machining according to claim 1, characterized in that the counter-voltage circuit comprises a second direct current power supply (V)₂) A resistor (R), a capacitor (C) and a fourth diode (D)₄) And a fifth diode (D)₅) Wherein one end of the capacitor (C) and the second switch tube (Q)₂) And a third diode (D)₃) Is connected to the connection point of the anode of a fifth diode (D)₅) And a first direct current power supply (V)₁) Is connected to the negative pole of a fifth diode (D)₅) Is connected with the other end of the capacitor (C), one end of the resistor (R) is connected with one end of the capacitor (C), the other end of the resistor (R) is connected with the other end of the capacitor (C), and a second direct current power supply (V)₂) Negative pole of (1) and second switching tube (Q)₂) And a third diode (D)₃) Is connected to the anode of a second direct current power supply (V)₂) And a fourth diode (D)₄) Is connected to the anode of a fourth diode (D)₄) And a capacitor (C) and a fifth diode (D)₅) Is connected with the capacitor (C), the resistor (R) and a second direct current power supply (V)₂) And line inductance (L) of the negative pole of_m) Is connected to a line inductance (L)_m) And a first direct current power supply (V)₁) The negative electrodes of the two electrodes are respectively connected with the two ends of the gap.

3. Micro-energy pulse power supply for high-speed reciprocating wire-cut electrical discharge machining according to claim 1, characterized in that the first switching tube (Q) ₁) A second switch tube (Q)₂) The SiC metal-oxide semiconductor field effect transistor SiC MOSFET is adopted, and the manufacturing material is SiC.

4. The micro-energy pulse power supply for high-speed reciprocating wire-cut electric discharge machine according to claim 1, wherein the driving circuit selects a driving chip with high-low end two-way driving and isolation characteristics.

5. The machining method of micro-energy pulse power supply for high-speed reciprocating wire-cut electric discharge machining according to any one of claims 1 to 4, characterized by comprising the steps of:

step 1: before starting the machining, the first switch tube (Q) of the main power circuit is controlled₁) And a second switching tube (Q)₂) Is turned off when the second DC power supply (V) in the back-voltage circuit₂) Through a fourth diode (D)₄) Charging the capacitor (C) and increasing the energy on the capacitor (C) until the voltage on the capacitor (C) rises to a level corresponding to the second DC power supply (V)₂) The voltages at the two ends are equal;

step 2: controlling the first switching tube (Q)₁) And a second switching tube (Q)₂) Is turned on when the first DC power supply (V) in the main power circuit is turned on₁) For line inductance (L)_m) And gap charging, when the gap voltage reaches the breakdown voltage, the gap is broken down, and the discharge machining is started;

And 3, step 3: when the gap current rises to a given peak current, the first switch tube (Q) is controlled₁) And a second switchClosing pipe (Q)₂) Is turned off when the first direct current power supply (V) is turned off₁) The gap current drops when the gap is no longer supplied, the circuit is divided into two parts, and the inductor (L) in the main power circuit passes the accumulated energy through the second diode (D)₂) Fed back to the first DC power supply (V)₁) The above step (1); fifth diode (D) in the counter-voltage circuit₅) The conduction raises the line inductance (L)_m) The voltage at the two ends enables the gap current to decrease with an increased slope;

and 4, step 4: after the current discharge is finished, the current enters between processing pulses to carry out deionization;

and 5: and (5) repeating the steps 1-4, and carrying out the next processing period.

6. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the following steps when executing the computer program:

step 1: before starting the machining, the first switch tube (Q) of the main power circuit is controlled₁) And a second switching tube (Q)₂) Is turned off when the second DC power supply (V) in the back-voltage circuit₂) Through a fourth diode (D)₄) Charging the capacitor (C) and increasing the energy on the capacitor (C) until the voltage on the capacitor (C) rises to a level corresponding to the second DC power supply (V) ₂) The voltages at both ends are equal;

and 2, step: control the first switch tube (Q)₁) And a second switching tube (Q)₂) Is turned on when the first DC power supply (V) in the main power circuit is turned on₁) For line inductance (L)_m) And gap charging, when the gap voltage reaches the breakdown voltage, the gap is broken down, and the electric discharge machining is started;

and step 3: when the gap current rises to a given peak current, the first switching tube (Q) is controlled₁) And a second switching tube (Q)₂) Is turned off when the first direct current power supply (V) is turned off₁) The gap current drops when the gap is no longer supplied, the circuit is divided into two parts, and the inductor (L) in the main power circuit passes the accumulated energy through the second diode (D)₂) Fed back to the first DC power supply (V)₁) The above step (1); back-voltage circuitMiddle fifth diode (D)₅) The conduction raises the line inductance (L)_m) The voltage at the two ends enables the gap current to decrease with an increased slope;

and 4, step 4: after the current discharge is finished, the current enters between processing pulses to carry out deionization;

and 5: and (5) repeating the steps 1-4, and carrying out the next processing period.

7. A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, carries out the steps of:

step 1: before starting the machining, the first switch tube (Q) of the main power circuit is controlled ₁) And a second switching tube (Q)₂) Is turned off when the second DC power supply (V) in the back-voltage circuit₂) Through a fourth diode (D)₄) Charging the capacitor (C) and increasing the energy on the capacitor (C) until the voltage on the capacitor (C) rises to a level corresponding to the second DC power supply (V)₂) The voltages at the two ends are equal;

step 2: controlling the first switching tube (Q)₁) And a second switching tube (Q)₂) Is turned on when the first DC power supply (V) in the main power circuit is turned on₁) Supply line inductance (L)_m) And gap charging, when the gap voltage reaches the breakdown voltage, the gap is broken down, and the discharge machining is started;

and step 3: when the gap current rises to a given peak current, the first switching tube (Q) is controlled₁) And a second switching tube (Q)₂) Is turned off when the first direct current power supply (V) is turned off₁) The gap current drops when the gap is no longer supplied, the circuit is divided into two parts, and the inductor (L) in the main power circuit passes the accumulated energy through the second diode (D)₂) Fed back to the first DC power supply (V)₁) The above step (1); fifth diode (D) in the counter-voltage circuit₅) The conduction raises the line inductance (L)_m) The voltage at the two ends enables the gap current to decrease with an increased slope;

and 4, step 4: after the current discharge is finished, the current enters between processing pulses to carry out deionization;

and 5: and (5) repeating the steps 1-4, and carrying out the next processing period.

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