A high-efficiency, low-voltage, micro-arc processing power supply and control method

Abstract

The present invention discloses a high-efficiency low-voltage micro-arc processing power supply and control method, including a DC power supply module, a high-voltage arc striking module, a low-voltage processing module, a discharge gap, a variable polarity continuous current module and a control and feedback module, wherein the input end of the high-voltage arc striking module and the low-voltage processing module are connected in parallel with the DC power supply module, the output end of the high-voltage arc striking module and the low-voltage processing module are connected in parallel with the discharge gap and the variable polarity continuous current module, the output voltage directions of the high-voltage arc striking module and the low-voltage processing module are the same in the same processing cycle, and the control and feedback module is electrically connected to the high-voltage arc striking module, the low-voltage processing module, the variable polarity continuous current module and the discharge gap, respectively. The high-efficiency low-voltage micro-arc processing power supply and control method described in the present invention solve the problem of processing accuracy, are suitable for fine processing, and improve surface processing quality.

Description

Technical Field

[0001] The present invention relates to the technical field of arc machining, and in particular to a high-efficiency low-voltage micro-arc machining special power supply and a control method. Background Art

[0002] Short arc machining technology is a cutting method that uses a short arc generated by electrode discharge to erode the workpiece material. It belongs to the category of electrical machining technology in the special machining industry. Compared with traditional contact machining, short arc machining can be used to process special materials such as high strength, high hardness, and high brittleness, as well as some complex surface processing. As an important component of the short arc machining system, the short arc power supply is used to provide pulse voltage to form discharge. Its performance has a great influence on the technical and economic indicators of short arc machining, such as accuracy, efficiency, electrode loss, and power utilization. The voltage provided by the general power supply is controlled at 20V-30V, which is suitable for rough machining. The surface quality after machining is poor. In order to solve the problem of machining accuracy, a high-efficiency, low-voltage micro-arc machining power supply specially used for fine machining is developed. Summary of the invention

[0003] The purpose of the present invention is to provide a high-efficiency, low-voltage micro-arc machining dedicated power supply and control method in order to solve the above-mentioned problems, so as to solve the technical problems that the existing short arc power supply in the prior art is not suitable for fine machining and the surface quality after machining is poor, and is used to provide machining energy and discharge gap breakdown voltage during low-voltage micro-arc machining.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a high-efficiency low-voltage micro-arc processing power supply, including a DC power supply module, a high-voltage arc-starting module, a low-voltage processing module, a discharge gap, a variable polarity continuous current module and a control and feedback module. The DC power supply module is obtained by rectifying and filtering the mains electricity, and provides electric energy for the high-voltage arc-starting module and the low-voltage processing module, and can be regarded as a constant voltage source. The input end of the high-voltage arc-starting module and the low-voltage processing module is connected in parallel with the DC power supply module, and the output end of the high-voltage arc-starting module and the low-voltage processing module is connected in parallel with the discharge gap and the variable polarity continuous current module. The output voltage directions of the high-voltage arc-starting module and the low-voltage processing module are the same in the same processing cycle, and the control and feedback module is electrically connected to the high-voltage arc-starting module, the low-voltage processing module, the variable polarity continuous current module and the discharge gap, respectively.

[0006] Further, the control and feedback module includes a power controller, a first voltage sensor, a second voltage sensor, a third voltage sensor and a current sensor;

[0007] The power supply controller transmits drive signals and feedback signals to the switching devices of the high-voltage arc ignition module and the low-voltage processing module. The drive signals include a first drive signal, a second drive signal, a third drive signal, a fourth drive signal, a fifth drive signal, and a sixth drive signal. The feedback signals include a first voltage sensor signal, a second voltage sensor signal, a third voltage sensor signal, and a current sensor signal.

[0008] Furthermore, the high-voltage arc-starting module includes a boost module and a high-voltage polarity-changing module, and its function is to provide high-voltage breakdown energy for the discharge gap to form a discharge channel. The input end of the boost module is connected to the DC power supply module, and the output end of the boost module is connected to the high-voltage polarity-changing module to provide power for the high-voltage polarity-changing module; the boost module is an isolated DC-DC converter, which can change the output voltage within a certain range according to the instructions of the power supply controller.

[0009] The high-voltage polarity conversion module includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube connected in a bridge type; the first switch tube and the fourth switch tube are connected to a first drive signal, and the second switch tube and the third switch tube are connected to a second drive signal; the input end of the high-voltage polarity conversion module is connected to a boost module, and the smooth high-voltage direct current is converted into a high-voltage pulse or direct current voltage with a positive voltage or a negative voltage by controlling the high-frequency switches of the four switch tubes; the output end of the high-voltage polarity conversion module is connected to a discharge gap, and a high-voltage pulse or direct current voltage is output to the discharge gap.

[0010] Furthermore, the low-voltage processing module includes a step-down module and a low-voltage polarity changing module, and its function is to provide low-voltage micro-arc processing energy for the discharge gap. The input end of the step-down module is connected to the DC power supply module, and the output end of the step-down module is connected to the low-voltage polarity changing module to provide power for the low-voltage polarity changing module; the step-down module is an isolated DC-DC converter, which can change the output voltage or current within a certain range according to the instructions of the power controller. During the discharge process, constant voltage output or constant current output can be selected according to the instructions of the power controller.

[0011] The low-voltage polarity conversion module includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube connected in a bridge type; the fifth switch tube is connected in series with a third diode, and the sixth switch tube is connected in series with a fourth diode; the fifth switch tube and the eighth switch tube are connected with a third drive signal, and the sixth switch tube and the seventh switch tube are connected with a fourth drive signal; the input end of the low-voltage polarity conversion module is connected to the step-down module, and the smooth low-voltage direct current is converted into a low-voltage pulse or direct current voltage with a positive voltage or a negative voltage by controlling the high-frequency switches of the four switch tubes; the output end of the low-voltage polarity conversion module is connected to the discharge gap, and a low-voltage pulse or direct current voltage is output to the discharge gap.

[0012] Furthermore, the variable polarity freewheeling module includes a ninth switch tube and a tenth switch tube; the ninth switch tube is connected in series with a first diode, the ninth switch tube is connected in parallel with a discharge gap and a freewheeling resistor, and the cathode of the first diode is connected to the workpiece electrode; the tenth switch tube is connected in series with a second diode in the same phase, the tenth switch tube is connected in parallel with a discharge gap and a freewheeling resistor, and the cathode of the second diode is connected to the tool electrode; the ninth switch tube is connected to a fifth drive signal, and the tenth switch tube is connected to a sixth drive signal.

[0013] Further, the signal input end of the first voltage sensor is connected to the signal output end of the boost module, the signal output end of the first voltage sensor is connected to the signal input end of the power controller, the signal input end of the second voltage sensor is connected to the signal output end of the step-down module, the signal output end of the second voltage sensor is connected to the signal input end of the power controller, the signal input end of the third voltage sensor is connected to the signal output end of the discharge gap, the signal output end of the third voltage sensor is connected to the signal input end of the power controller, the signal input end of the current sensor is connected to the signal output end of the discharge gap, and the signal output end of the current sensor is connected to the signal input end of the power controller

[0014] A control method for a high-efficiency low-voltage micro-arc machining power supply is provided, wherein the direction in which current flows from a workpiece electrode to a tool electrode is defined as the positive direction of current and voltage, and comprises the following steps:

[0015] S1: The power supply is started, and the voltage across the DC power supply module is U; all driving signals are at low level, and all switch tubes in the power supply are in the cut-off state; the first voltage sensor, the second voltage sensor, the third voltage sensor, and the current sensor detect the voltage and current values ​​in real time and feed them back to the power supply controller;

[0016] S2: The boost module outputs voltage according to the instruction of the power controller, and the power controller adjusts the instruction to the boost module according to the feedback value of the first voltage sensor to output a stable voltage; the buck module outputs voltage according to the instruction of the power controller, and the power controller adjusts the instruction to the buck module according to the feedback value of the second voltage sensor to output a stable voltage;

[0017] S3: The discharge cycle starts, the power controller outputs a drive signal, and selects positive voltage output or negative voltage output;

[0018] S4: When the tool electrode approaches the workpiece electrode, the discharge gap is broken down by the high voltage output by the high-voltage arc ignition module. At this time, the current sensor detects the current value and feeds it back to the power controller. The power controller stops the output of the first drive signal or the second drive signal, and the high-voltage arc ignition module stops outputting voltage.

[0019] When the power supply is in constant voltage output mode: the power supply controller adjusts the instruction to the step-down module according to the feedback value of the third voltage sensor to output a stable voltage;

[0020] When the power supply is in constant current output mode: the power supply controller adjusts the instruction to the buck module according to the feedback value of the current sensor to output a stable current;

[0021] S5: the voltage controller stops outputting the third drive signal or the fourth drive signal, and the low-voltage processing module stops outputting voltage;

[0022] S6: After one cycle of discharge is completed, steps S3, S4, and S5 are repeated to start the next cycle of discharge.

[0023] Furthermore, the method for the power controller to select the voltage output in step S3 includes the following steps:

[0024] When the positive voltage is output: the power controller outputs the first drive signal, the fourth drive signal, and the fifth drive signal, and the other drive signals are all at low level; wherein the first drive signal and the fourth drive signal are DC signals or pulse signals, and the fifth drive signal is a DC signal; at this time, the first switch tube and the fourth switch tube output high-voltage pulses or DC voltages according to the first drive signal; the sixth switch tube and the seventh switch tube output low-voltage pulses or DC voltages according to the second drive signal; the ninth switch tube is turned on, and forms a freewheeling loop with the freewheeling resistor, and the tenth switch tube is disconnected at the same time;

[0025] When the negative voltage is output: the power controller outputs the second drive signal, the third drive signal, and the sixth drive signal, and the other drive signals are all low level; the second drive signal and the third drive signal are DC signals or pulse signals, and the sixth drive signal is a DC signal; at this time, the second switch tube and the third switch tube output high-voltage pulses or DC voltage according to the second drive signal; the fifth switch tube and the eighth switch tube output low-voltage pulses or DC voltage according to the third drive signal; the tenth switch tube is turned on, and forms a freewheeling loop with the freewheeling resistor, and the ninth switch tube is disconnected at the same time.

[0026] Furthermore, the forward withstand voltage values ​​of the seventh switch tube and the eighth switch tube and the reverse withstand voltage values ​​of the first diode, the second diode, the third diode and the fourth diode need to be greater than the maximum output voltage value of the high-voltage arc striking module.

[0027] Furthermore, steps S3, S4, and S5 constitute a processing cycle; in unipolar processing, the voltage directions of multiple processing cycles are the same; in variable polarity processing, after a processing cycle ends, the voltage direction of the next processing cycle is determined by a preset program to be the same as or different from the previous processing cycle.

[0028] The beneficial effects are:

[0029] It adopts an integrated structural design, fully utilizes the internal space of the device, integrates the functions of water spraying and wiping, has a good cleaning ability for stubborn impurities attached to photovoltaic panels, and can realize automatic replenishment of water and electricity, thereby improving the endurance of the device and reducing the labor intensity of maintenance personnel. It is suitable for large-scale photovoltaic applications, can significantly reduce production costs, and is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a schematic diagram of a high-efficiency, low-voltage, micro-arc processing power supply of the present invention;

[0032] Figure 2 This is the principle diagram of the high-efficiency low-voltage micro-arc processing special power supply of the present invention.

[0033] The following are the descriptions of the reference numerals:

[0034] 1. DC power supply module; 2. High-voltage arc ignition module; 21. Boost module; 22. High-voltage polarity conversion module; TR1. First switch tube; TR2. Second switch tube; TR3. Third switch tube; TR4. Fourth switch tube; 3. Low-voltage processing module; 31. Step-down module; 32. Low-voltage polarity conversion module; TR5. Fifth switch tube; TR6. Sixth switch tube; TR7. Seventh switch tube; TR8. Eighth switch tube; D3. Third diode; D4. Fourth diode; 4. Discharge gap; 5. Polarity conversion freewheeling module; T R9, the ninth switch tube; TR10, the tenth switch tube; D1, the first diode; D2, the second diode; R1, the freewheeling resistor; 6, the control and feedback module; 61, the power controller; S1, the first voltage sensor; S2, the second voltage sensor; S3, the third voltage sensor; S4, the current sensor; Q1, the first drive signal; Q2, the second drive signal; Q3, the third drive signal; Q4, the fourth drive signal; Q5, the fifth drive signal; Q6, the sixth drive signal; 7, the workpiece electrode; 8, the tool electrode. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0036] See also Figure 1-Figure 2 As shown, the present invention provides a high-efficiency low-voltage micro-arc processing power supply, including a DC power supply module 1, a high-voltage arc-starting module 2, a low-voltage processing module 3, a discharge gap 4, a variable polarity continuous current module 5 and a control and feedback module 6. The DC power supply module 1 is obtained by rectifying and filtering the mains electricity, and provides power for the high-voltage arc-starting module 2 and the low-voltage processing module 3, and can be regarded as a constant voltage source. The input ends of the high-voltage arc-starting module 2 and the low-voltage processing module 3 are connected in parallel with the DC power supply module 1, and the output ends of the high-voltage arc-starting module 2 and the low-voltage processing module 3 are connected in parallel with the discharge gap 4 and the variable polarity continuous current module 5. The output voltage directions of the high-voltage arc-starting module 2 and the low-voltage processing module 3 are the same in the same processing cycle, and the control and feedback module 6 is electrically connected to the high-voltage arc-starting module 2, the low-voltage processing module 3, the variable polarity continuous current module 5 and the discharge gap 4, respectively.

[0037] In another embodiment of the present invention, the control and feedback module 6 includes a power controller 61, a first voltage sensor S1, a second voltage sensor S2, a third voltage sensor S3 and a current sensor S4;

[0038] The power controller 61 transmits drive signals and feedback signals to the switch devices of the boost module 21 and the buck module 31; the drive signals include the first drive signal Q1, the second drive signal Q2, the third drive signal Q3, the fourth drive signal Q4, the fifth drive signal Q5, and the sixth drive signal Q6, and the feedback signals include the first voltage sensor S1 signal, the second voltage sensor S2 signal, the third voltage sensor S3 signal, and the current sensor S4 signal. The signal input end of the first voltage sensor S1 is connected to the signal output end of the boost module 21, and the signal output end of the first voltage sensor S1 is connected to the signal input end of the power controller 61. After the power is started, the voltage UH at the output ends C and D of the boost module 21 is detected in real time, and the voltage value is fed back to the power controller 61. The signal input end of the second voltage sensor S2 is connected to the signal output end of the buck module 31, and the signal output end of the second voltage sensor S2 is connected to the signal input end of the power controller 61. After the power is started, the voltage UL at the output ends E and F of the buck module 31 is detected in real time, and the voltage value is fed back to the power controller 61. The signal input end of the third voltage sensor S3 is connected to the signal output end of the discharge gap 4, and the signal output end of the third voltage sensor S3 is connected to the signal input end of the power controller 61. After the power is started, the voltage UO at points G and H at both ends of the discharge gap 4 is detected in real time, and the voltage value is fed back to the power controller 61. The signal input end of the current sensor S4 is connected to the signal output end of the discharge gap 4, and the signal output end of the current sensor S4 is connected to the signal input end of the power controller 61. After the power is started, the current IO flowing through the discharge gap 4, i.e., point G or H, is detected in real time, and the current value is fed back to the power controller 61.

[0039] In another embodiment of the present invention, Figure 1-Figure 2 As shown, the high-voltage arc striking module 2 includes a boost module 21 and a high-voltage polarity changing module 22, and its function is to provide high-voltage breakdown energy for the discharge gap 4 to form a discharge channel. The input end of the boost module 21 is connected to the DC power supply module 1, and the output end of the boost module 21 is connected to the high-voltage polarity changing module 22 to provide electric energy for the high-voltage polarity changing module 22; the boost module 21 is an isolated DC-DC converter, which can change the output voltage within a certain range according to the instruction of the power supply controller 61.

[0040] The high-voltage polarity conversion module 22 includes a first switch tube TR1, a second switch tube TR2, a third switch tube TR3, and a fourth switch tube TR4 connected in a bridge type; the first switch tube TR1 and the fourth switch tube TR4 are connected to a first drive signal Q1, and the second switch tube TR2 and the third switch tube TR3 are connected to a second drive signal Q2; the input end of the high-voltage polarity conversion module 22 is connected to the boost module 21, and the smooth high-voltage direct current with a voltage of UH is converted into a high-voltage pulse with a pulse amplitude of UH positive voltage or -UH negative voltage, or a direct current voltage with a voltage of UH or a direct current voltage with a voltage of -UH by controlling the high-frequency switches of the four switch tubes; the output end of the high-voltage polarity conversion module 22 is connected to the discharge gap 4, and outputs a high-voltage pulse with an amplitude of UH or -UH, or a direct current voltage with a voltage of UH or -UH for the discharge gap 4.

[0041] In another embodiment of the present invention, Figure 1-Figure 2 As shown, the low-voltage processing module 3 includes a step-down module 31 and a low-voltage polarity changing module 32, and its function is to provide low-voltage micro-arc processing energy for the discharge gap 4. The input end of the step-down module 31 is connected to the DC power supply module 1, and the output end of the step-down module 31 is connected to the low-voltage polarity changing module 32 to provide electrical energy for the low-voltage polarity changing module 32; Figure 2 As shown, the buck module 31 is a full-bridge DC-DC converter, and its feedback voltage signal is provided by the second voltage sensor S2, the third voltage sensor S3, and the current sensor S4. It can change the output voltage UL or current I within a certain range according to the instructions of the power controller 61. During the discharge process, it can select a constant voltage output UL or a constant current output I according to the instructions of the power controller 61.

[0042] The low voltage polarity conversion module 32 includes a fifth switch tube TR5, a sixth switch tube TR6, a seventh switch tube TR7 and an eighth switch tube TR8 connected in a bridge type; the fifth switch tube TR5 is connected in series with a third diode D3, and the sixth switch tube TR6 is connected in series with a fourth diode D4; the fifth switch tube TR5 and the eighth switch tube TR8 are connected to a third drive signal Q3, and the sixth switch tube TR6 and the seventh switch tube TR7 are connected to a fourth drive signal Q4; the input end of the low voltage polarity conversion module 32 is connected to the step-down module 31, and the smooth low voltage direct current with a voltage of UL is converted into a low voltage pulse with a positive voltage of UL or a negative voltage of -UL, or a direct current voltage of UL or a direct current voltage of -UL by controlling the high frequency switches of the four switch tubes; the output end of the low voltage polarity conversion module 32 is connected to the discharge gap 4, and outputs a low voltage pulse with an amplitude of UL or -UL, or a direct current voltage of UL or -UL, or a current I or -I for the discharge gap 4.

[0043] In another embodiment of the present invention, Figure 1-Figure 2As shown, the variable polarity freewheeling module 5 includes a ninth switch tube TR9 and a tenth switch tube TR10; the ninth switch tube TR9 is connected in series with a first diode D1, the ninth switch tube TR9 is connected in parallel with a discharge gap 4 and a freewheeling resistor R1, and the cathode of the first diode D1 is connected to a workpiece electrode 7; the tenth switch tube TR10 is connected in series with a second diode D2 in the same phase, the tenth switch tube TR10 is connected in parallel with a discharge gap 4 and a freewheeling resistor R1, and the cathode of the second diode D2 is connected to a tool electrode 8; the ninth switch tube TR9 is connected to a fifth drive signal Q5, and the tenth switch tube TR10 is connected to a sixth drive signal Q6.

[0044] A control method for a high-efficiency low-voltage micro-arc machining power supply is provided, wherein the direction in which the current flows from the workpiece electrode 7 to the tool electrode 8 is defined as the positive direction of the current and the voltage, and comprises the following steps:

[0045] S1: The power supply is started, and the voltage between points A and B at both ends of the DC power supply module 1 is U; all driving signals are at low level, and all switch tubes in the power supply are in the cut-off state; the first voltage sensor S1, the second voltage sensor S2, the third voltage sensor S3, and the current sensor S4 detect the voltage value and the current value in real time and feed them back to the power supply controller 61;

[0046] S2: The boost module 21 outputs the voltage U according to the instruction of the power controller 61 H The power controller 61 adjusts the duty cycle of the full-bridge DC-DC converter switch of the boost module 21 according to the feedback value of the first voltage sensor S1 to output a stable voltage U H The step-down module 31 outputs the voltage U according to the instruction of the power controller 61 L The power controller 61 adjusts the duty cycle of the full-bridge DC-DC converter switch of the step-down module 31 according to the feedback value of the second voltage sensor S2 to output a stable voltage U L ;

[0047] S3: The discharge cycle starts, the power controller 61 outputs a driving signal, and selects positive voltage output or negative voltage output;

[0048] S4: When the tool electrode 8 approaches the workpiece electrode 7, the discharge gap 4 is connected to the high voltage U output by the high voltage arc striking module 2. H The current sensor S4 detects the current value and feeds it back to the power controller 61, which stops the output of the first drive signal Q1 or the second drive signal Q2, and the high-voltage arc ignition module 2 stops outputting the voltage U H ;

[0049] When the power supply is in constant voltage output mode: the power supply controller 61 adjusts the instruction to the voltage reduction module 31 according to the feedback value of the third voltage sensor S3 to output a stable voltage U O =U L ;

[0050] When the power supply is in constant current output mode: the power supply controller 61 adjusts the instruction to the step-down module 31 according to the feedback value of the current sensor S4 to output a stable current I O =I;

[0051] S5: the voltage controller stops outputting the third drive signal Q3 or the fourth drive signal Q4, and the low-voltage processing module 3 stops outputting voltage;

[0052] S6: After one cycle of discharge is completed, steps S3, S4, and S5 are repeated to start the next cycle of discharge.

[0053] In another embodiment of the present invention, the method for the power controller 61 to select the voltage output in step S3 includes the following steps:

[0054] When the positive voltage is output: the power controller 61 outputs the first drive signal Q1, the fourth drive signal Q4, and the fifth drive signal Q5, and the other drive signals are all low level; the first drive signal Q1 and the fourth drive signal Q4 are DC signals or pulse signals, and the fifth drive signal Q5 is a DC signal; at this time, the first switch tube TR1 and the fourth switch tube TR4 output an amplitude of U according to the first drive signal Q1 H The high voltage pulse or voltage is U H The sixth switch tube TR6 and the seventh switch tube TR7 output an amplitude of U according to the second drive signal Q2 L The low voltage pulse or voltage is U L The ninth switch tube TR9 is turned on to form a freewheeling loop with the freewheeling resistor R1, and the tenth switch tube TR10 is turned off;

[0055] When the negative voltage is output: the power controller 61 outputs the second drive signal Q2, the third drive signal Q3, and the sixth drive signal Q6, and the other drive signals are all low level; the second drive signal Q2 and the third drive signal Q3 are DC signals or pulse signals, and the sixth drive signal Q6 is a DC signal; at this time, the second switch tube TR2 and the third switch tube TR3 output an amplitude of U according to the second drive signal Q2. H The high voltage pulse or voltage is U H The fifth switch tube TR5 and the eighth switch tube TR8 output an amplitude of U according to the third drive signal Q3 L The low voltage pulse or voltage is U L The tenth switch tube TR10 is turned on to form a freewheeling loop with the freewheeling resistor R1, while the ninth switch tube TR9 is turned off.

[0056] In another embodiment of the present invention, Figure 1-Figure 2As shown, the forward withstand voltage of the seventh switch tube TR7 and the eighth switch tube TR8 and the reverse withstand voltage of the first diode, the second diode D2, the third diode D3, and the fourth diode D4 must be greater than the maximum output voltage value U of the high-voltage arc striking module 2. H .

[0057] In another embodiment of the present invention, Figure 1-Figure 2 As shown, steps S3, S4, and S5 constitute a processing cycle; in unipolar processing, the voltage directions of multiple processing cycles are the same; in variable polarity processing, after a processing cycle ends, the voltage direction of the next processing cycle is determined by a preset program to be the same as or different from the previous processing cycle.

[0058] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A control method for a high-efficiency low-voltage micro-arc processing power supply, using a high-efficiency low-voltage micro-arc processing power supply, comprising a DC power supply module, a high-voltage arc striking module, a low-voltage processing module, a discharge gap, a variable polarity freewheeling module and a control and feedback module, wherein the input end of the high-voltage arc striking module and the low-voltage processing module are connected in parallel with the DC power supply module, the output end of the high-voltage arc striking module and the low-voltage processing module are connected in parallel with the discharge gap and the variable polarity freewheeling module, the output voltage directions of the high-voltage arc striking module and the low-voltage processing module are the same in the same processing cycle, and the control and feedback module is electrically connected to the high-voltage arc striking module, the low-voltage processing module, the variable polarity freewheeling module and the discharge gap respectively; The control and feedback module includes a power controller, a first voltage sensor, a second voltage sensor, a third voltage sensor and a current sensor; the power controller transmits a drive signal and a feedback signal to the switch devices of the high-voltage arc ignition module and the low-voltage processing module, and the drive signal includes a first drive signal, a second drive signal, a third drive signal, a fourth drive signal, a fifth drive signal and a sixth drive signal; The high-voltage arc striking module includes a boost module and a high-voltage polarity changing module; the input end of the boost module is connected to the DC power supply module, and the output end of the boost module is connected to the high-voltage polarity changing module; The high-voltage polarity conversion module includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube connected in a bridge type; the first switch tube and the fourth switch tube are connected to a first drive signal, and the second switch tube and the third switch tube are connected to a second drive signal; the input end of the high-voltage polarity conversion module is connected to the boost module, and the output end of the high-voltage polarity conversion module is connected to the discharge gap; The low-voltage processing module includes a step-down module and a low-voltage polarity conversion module; the input end of the step-down module is connected to the DC power supply module, and the output end of the step-down module is connected to the low-voltage polarity conversion module; the low-voltage polarity conversion module includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube connected in a bridge type; the fifth switch tube is connected in series with a third diode, and the sixth switch tube is connected in series with a fourth diode; the fifth switch tube and the eighth switch tube are connected with a third drive signal, and the sixth switch tube and the seventh switch tube are connected with a fourth drive signal; the input end of the low-voltage polarity conversion module is connected to the step-down module, and the output end of the low-voltage polarity conversion module is connected to the discharge gap; The polarity-changing freewheeling module includes a ninth switch tube and a tenth switch tube; the ninth switch tube is connected in series with a first diode, the ninth switch tube is connected in parallel with a discharge gap and a freewheeling resistor, and the cathode of the first diode is connected to a workpiece electrode; the tenth switch tube is connected in series with a second diode in phase, the tenth switch tube is connected in parallel with a discharge gap and a freewheeling resistor, and the cathode of the second diode is connected to a tool electrode; the ninth switch tube is connected to a fifth drive signal, and the tenth switch tube is connected to a sixth drive signal; The signal input end of the first voltage sensor is connected to the signal output end of the boost module, the signal output end of the first voltage sensor is connected to the signal input end of the power controller, the signal input end of the second voltage sensor is connected to the signal output end of the step-down module, the signal output end of the second voltage sensor is connected to the signal input end of the power controller, the signal input end of the third voltage sensor is connected to the signal output end of the discharge gap, the signal output end of the third voltage sensor is connected to the signal input end of the power controller, the signal input end of the current sensor is connected to the signal output end of the discharge gap, and the signal output end of the current sensor is connected to the signal input end of the power controller; the direction of current flowing from the workpiece electrode to the tool electrode is defined as the positive direction of current and voltage, characterized in that The following steps are involved: S1: The power supply is started, and the voltage across the DC power supply module is U; all driving signals are at low level, and all switch tubes in the power supply are in the cut-off state; the first voltage sensor, the second voltage sensor, the third voltage sensor, and the current sensor detect the voltage and current values ​​in real time and feed them back to the power supply controller; S2: The boost module outputs voltage according to the instruction of the power controller, and the power controller adjusts the instruction to the boost module according to the feedback value of the first voltage sensor to output a stable voltage; the buck module outputs voltage according to the instruction of the power controller, and the power controller adjusts the instruction to the buck module according to the feedback value of the second voltage sensor to output a stable voltage; S3: The discharge cycle starts, the power controller outputs a drive signal, and selects positive voltage output or negative voltage output; S4: When the tool electrode approaches the workpiece electrode, the discharge gap is broken down by the high voltage output by the high-voltage arc ignition module. At this time, the current sensor detects the current value and feeds it back to the power controller. The power controller stops the output of the first drive signal or the second drive signal, and the high-voltage arc ignition module stops outputting voltage. When the power supply is in constant voltage output mode: the power supply controller adjusts the instruction to the step-down module according to the feedback value of the third voltage sensor to output a stable voltage; When the power supply is in constant current output mode: the power supply controller adjusts the instruction to the buck module according to the feedback value of the current sensor to output a stable current; S5: the voltage controller stops outputting the third drive signal or the fourth drive signal, and the low-voltage processing module stops outputting voltage; S6: After one cycle of discharge is completed, steps S3, S4, and S5 are repeated to start the next cycle of discharge; The method for the power controller to select the voltage output in step S3 comprises the following steps: When the positive voltage is output: the power controller outputs the first drive signal, the fourth drive signal, and the fifth drive signal, and the other drive signals are all at low level; wherein the first drive signal and the fourth drive signal are DC signals or pulse signals, and the fifth drive signal is a DC signal; at this time, the first switch tube and the fourth switch tube output high-voltage pulses or DC voltages according to the first drive signal; the sixth switch tube and the seventh switch tube output low-voltage pulses or DC voltages according to the second drive signal; the ninth switch tube is turned on, and forms a freewheeling loop with the freewheeling resistor, and the tenth switch tube is disconnected at the same time; When the negative voltage is output: the power controller outputs the second drive signal, the third drive signal, and the sixth drive signal, and the other drive signals are all low level; the second drive signal and the third drive signal are DC signals or pulse signals, and the sixth drive signal is a DC signal; at this time, the second switch tube and the third switch tube output high-voltage pulses or DC voltage according to the second drive signal; the fifth switch tube and the eighth switch tube output low-voltage pulses or DC voltage according to the third drive signal; the tenth switch tube is turned on, and forms a freewheeling loop with the freewheeling resistor, and the ninth switch tube is disconnected at the same time.

2. The control method of the high-efficiency low-voltage micro-arc machining dedicated power supply according to claim 1 is characterized in that: The forward withstand voltage values ​​of the seventh switch tube and the eighth switch tube and the reverse withstand voltage values ​​of the first diode, the second diode, the third diode and the fourth diode need to be greater than the maximum output voltage value of the high-voltage arc striking module.

3. The control method of the high-efficiency low-voltage micro-arc machining dedicated power supply according to claim 2 is characterized in that: Steps S3, S4 and S5 constitute a processing cycle. In unipolar processing, the voltage direction of multiple processing cycles is the same. In variable polarity processing, after one processing cycle is completed, the voltage direction of the next processing cycle is determined by a preset program to be the same as or different from the previous processing cycle.

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