Power supply device of space additive manufacturing electron gun and forming process control method

Abstract

The invention relates to a power supply device of a space additive manufacturing electron gun and a forming process control method, is suitable for an on-orbit additive manufacturing cold cathode electron gun, and is a device capable of providing cathode negative high voltage, pulse current and electrostatic field voltage, regulating and controlling the working voltage of a filament bundle coaxial cold cathode electron gun and promoting droplet transition in a microgravity environment. Aiming at the defects in the prior art and the particularity of a microgravity additive manufacturing environment, an electrostatic field terminal is arranged at a beam output end of a filament bundle coaxial cold cathode electron gun, electrostatic field voltage is provided for the electrostatic field terminal, molten drops are subjected to electrostatic field force, and molten drop transition is accelerated. In order to enable the metal molten drops to be deposited and formed orderly and controllably in a microgravity environment, pulse current is introduced to further promote molten drop transition. Through the method, the power supply device of the space additive manufacturing electron gun and the forming process control method provided by the invention meet the high-efficiency, high-quality and rapid manufacturing requirements of the coaxial cold cathode electron gun for the tow in the space environment.

Description

Technical Field

[0001] The present application relates to the technical field of electron beam additive manufacturing, and in particular to a power supply device and a forming process control method for an electron gun for space additive manufacturing. Background Art

[0002] Manned spacecraft, space stations, etc. are important aircraft for human exploration of space. In order to improve the long-term working stability and reliability of on-orbit aircraft, it is usually necessary to reserve a large number of spare parts in a limited space, which seriously compresses the living and experimental space of astronauts; at the same time, the ground needs to reserve the same number of spare parts that can be launched at any time. However, only a very small number of spare parts will be actually used for replacement, less than 5%. In order to deal with all potential failures of on-orbit aircraft, various types of spare parts need to be prepared to deal with random failures. The reserve of spare parts is far greater than the number of parts that may be used in the future. Providing protection for deep space manned spaceflight in this way will inevitably cause a lot of resource waste. In future space exploration, space trusses required for ultra-large area antennas, on-orbit service platforms, etc. are indispensable. Their geometric dimensions often need to reach hundreds or even tens of kilometers, and the mass will reach 10,000 tons. If a structure of this scale follows the conventional "ground manufacturing, rocket transportation, and space application" model, it is almost impossible to implement.

[0003] Additive manufacturing technology makes it possible for astronauts to manufacture aircraft maintenance parts and large trusses on orbit. However, not all additive manufacturing technologies are applicable in the extreme environment of space. Compared with other additive manufacturing technologies, electron beam fuse additive manufacturing technology has become an important direction for the development of on-orbit additive manufacturing technology due to its advantages such as high electron beam energy conversion efficiency, suitability for vacuum environment, and easy constraint of wire materials. It has good application prospects. The National Aeronautics and Space Administration (NASA) regards on-orbit additive manufacturing technology as one of the key technologies to support deep space exploration missions. The electron beam free forming (EBF3) system developed by NASA Langley Research Center has been tested in a microgravity environment simulated by a jet aircraft. At present, the common axial wire feeding mode of electron beam fuse additive manufacturing technology in a microgravity environment has shortcomings such as difficulty in wire bundle centering, heating shadow area, and excessive heat input, which limits its future development space. Summary of the invention

[0004] The present application provides a power supply device and a forming process control method for a space additive manufacturing electron gun, which meet the requirements of long-term stable operation of the space additive manufacturing electron gun and effectively improve the forming quality and forming efficiency.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] The present application provides a power supply device for a space additive manufacturing electron gun, comprising:

[0007] High voltage power supply, pulse power supply, electrostatic field power supply, DSP control system, gas flow controller, host computer;

[0008] The negative electrode of the high-voltage power supply is connected to the annular cathode, and the positive electrode of the high-voltage power supply is connected to the metal substrate through the beam sampling resistor; the negative electrode of the pulse power supply is connected to the metal wire disc support, and the positive electrode of the pulse power supply is grounded; the negative electrode of the electrostatic field power supply is connected to the electrostatic field terminal, and the positive electrode of the electrostatic field power supply is grounded; the DSP control system is respectively connected to the high-voltage power supply, the pulse power supply, the electrostatic field power supply, the gas flow controller, and the host computer; the gas flow controller is connected to the electron gun chamber;

[0009] The DSP control system is used to: receive the start instruction of the upper computer; control the output voltage of the high-voltage power supply to adjust the beam size in the electron beam energy convergence area; control the output pulse current of the pulse power supply to regulate the droplet transition rate; control the output voltage of the electrostatic field power supply to accelerate the transition of the droplet to the substrate; control the gas flow output by the gas flow controller to adjust the beam size.

[0010] Further, the high-voltage power supply includes: a high-voltage power supply anti-reverse connection unit, a high-voltage power supply first inverter unit, a high-voltage power supply first transformer unit, a high-voltage power supply first rectifier circuit, a high-voltage power supply second inverter unit, a high-voltage power supply second transformer unit, a high-voltage power supply second rectifier circuit, a high-voltage power supply voltage sensor, a high-voltage DC power supply control circuit, a high-voltage power supply first inverter drive circuit, a high-voltage inverter power supply control circuit, and a high-voltage power supply second inverter drive circuit;

[0011] The input of the high-voltage power supply reverse connection protection unit is a DC power supply. The high-voltage power supply reverse connection protection unit includes a diode D0, a diode D1, an inductor L0, and a capacitor C0, wherein the anode of the diode D0 is connected to the positive end of the DC power supply, and the cathode of the diode D0 is connected to one end of the inductor L0; the cathode of the diode D1 is connected to the negative end of the DC power supply, the anode of the diode D1 is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to the end of the inductor L0 that is not connected to the diode D0;

[0012] The output end of the high-voltage power supply anti-reverse connection unit is connected to the first inverter unit of the high-voltage power supply, which is a full-bridge circuit composed of power switching devices; the output end of the first inverter unit of the high-voltage power supply is connected to the power transformer T of the first transformer unit of the high-voltage power supply 10 The primary side of the power transformer T 10 The secondary side is connected to the input end of the first rectifier circuit of the high-voltage power supply; the output end of the first rectifier circuit of the high-voltage power supply is connected in parallel with the high-voltage power supply voltage sensor; the high-voltage power supply voltage sensor detects the output voltage signal U of the first rectifier circuit of the high-voltage power supply f , will U f Feedback to the high voltage DC power supply control circuit;

[0013] The output end of the first rectifier circuit of the high-voltage power supply is connected to the second inverter unit of the high-voltage power supply; the second inverter unit of the high-voltage power supply is also a full-bridge circuit composed of power switching devices, and the gates of each power switching device are respectively connected to the second inverter drive circuit of the high-voltage power supply, and the second inverter drive circuit of the high-voltage power supply receives a PWM signal from the high-voltage inverter power supply control circuit to control each power switching device to be turned on at full frequency and full pulse width;

[0014] The second rectifier circuit of the high voltage power supply includes a high voltage diode D 11 , D 12 , D 13 , D 14 The rectifier bridge and high voltage diode D 15 , D 16 , D 17 , D 18 The rectifier bridge consists of a high voltage diode D 11 , D 12 , D 13 , D 14 The positive end of the rectifier bridge and the high voltage diode D 15 , D 16 , D 17 , D 18 The negative terminal of the rectifier bridge is connected;

[0015] The output end of the second inverter unit of the high-voltage power supply is connected to the second transformer unit of the high-voltage power supply. The second transformer unit of the high-voltage power supply includes two high-voltage transformers T 11 , T 12 , high voltage transformer T 11 , T 12 The primary side is connected in parallel to the output end of the second inverter unit of the high-voltage power supply, and the high-voltage transformer T 11 The two ends of the secondary side are connected to the high voltage diode D 11 , D 12 , D 13 , D 14 Rectifier bridge composed of; high voltage transformer T 12 The two ends of the secondary side are connected to the high voltage diode D 15 , D 16 , D 17 , D 18 The rectifier bridge is composed of

[0016] The negative output terminal of the second rectifier circuit of the high-voltage power supply is connected to the annular cathode; the positive output terminal of the second rectifier circuit of the high-voltage power supply is connected to one end of the beam sampling resistor R1, and the beam sampling signal I bf Take it out from this end of the beam current sampling resistor R1, and the other end of the beam current sampling resistor R1 is connected to the reference ground.

[0017] Furthermore, a high-voltage power supply high-voltage sampling circuit is connected in parallel between the negative output terminal and the positive output terminal of the second rectifier circuit of the high-voltage power supply, and the high-voltage power supply high-voltage sampling circuit includes a plurality of voltage-dividing resistors and a high-voltage sampling resistor R0; the plurality of voltage-dividing resistors and the high-voltage sampling resistor R0 are sequentially connected in series, and a high-voltage feedback signal U is collected at a connection point between the plurality of voltage-dividing resistors and the high-voltage sampling resistor R0. hvf , the other end of the high-voltage sampling resistor R0 is connected to the positive output end of the second rectifier circuit of the high-voltage power supply;

[0018] High voltage feedback signal U hvf Feedback to the DSP control system, DSP control system according to the high voltage given signal U hvg With the high voltage feedback signal U hvf Perform PID adjustment and output U hvgg The high-voltage DC power supply control circuit receives the output voltage signal U from the high-voltage power supply first rectifier circuit detected by the high-voltage power supply voltage sensor. f ;

[0019] U f with U hvgg After PID adjustment by the high-voltage DC power supply control circuit, the output PWM signal pulse width is adjusted, and then after passing through the first inverter drive circuit of the high-voltage power supply, four PWM signals are output to the gates of each power switch device in the full-bridge circuit of the first inverter unit of the high-voltage power supply, and the conduction time of the corresponding power switch device is adjusted, thereby adjusting the output voltage of the first rectifier circuit of the high-voltage power supply and the output voltage of the second rectifier circuit of the high-voltage power supply, so as to adjust the negative high voltage output by the high-voltage power supply to the annular cathode.

[0020] Furthermore, the pulse power supply includes: a pulse power supply anti-reverse connection unit, a pulse power supply inverter unit, a pulse power supply transformer unit, a pulse power supply rectifier circuit, a pulse power supply discharge switch, a pulse power supply discharge switch drive circuit, a pulse power supply current sensor, a filter inductor L 202 , charging capacitor C 202 , pulse power supply control circuit, pulse power supply inverter drive circuit;

[0021] The pulse power supply reverse connection protection unit input is a DC power supply, and the pulse power supply reverse connection protection unit includes a diode D 201 、Diode D 202 、Inductance L 201 , capacitor C 201 , where diode D 201 The anode of the diode D is connected to the positive terminal of the DC power supply. 201 The cathode connection inductance L 201 One end of the diode D 202 The cathode of the diode D is connected to the negative terminal of the DC power supply. 202The anode connection capacitance C 201 One end of the capacitor C 201 The other end of the inductor L 201 Not with diode D 201 One end of the connection;

[0022] The output end of the pulse power supply anti-reverse connection unit is connected to the pulse power supply inverter unit, which is a bridge circuit composed of power switching devices; the output end of the pulse power supply inverter unit is connected to the transformer T of the pulse power supply transformer unit 20 The primary side of the transformer T 20 The two ends of the secondary side are connected to the diode D 21 , D 22 , D 23 , D 24 The input end of the pulse power supply rectifier circuit composed of the pulse power supply;

[0023] The negative output terminal of the pulse power rectifier circuit is connected to the filter inductor L 202 One end of the filter inductor L 202 The other end is connected in series with the pulse power supply current sensor and then connected to the charging capacitor C 202 One end of the charging capacitor C 202 The other end is connected to the positive output end of the pulse power rectifier circuit; the positive output end of the pulse power rectifier circuit is also connected to the current limiting resistor R 201 One end of the current limiting resistor R 201 The other end is grounded;

[0024] Filter inductor L 202 With charging capacitor C 202 The common point of connection is connected to the emitter of the pulse power supply discharge switch, which is composed of a single high-power IGBT or multiple IGBTs connected in parallel. The collector of the pulse power supply discharge switch is connected to the wire coil support; the wire coil support is insulated from the ground.

[0025] Furthermore, the charging capacitor C 202 The pulse power supply voltage sensor is connected in parallel at both ends. When the pulse power supply discharge switch is not turned on, the pulse power supply voltage sensor collects the charging voltage signal U pf Feedback to the pulse power supply control circuit, the pulse power supply control circuit gives the DSP control system a charging voltage signal U pgg with U pf Make comparisons;

[0026] If U pgg >U pf The pulse power supply control circuit collects the charging current signal I from the pulse power supply current sensor. pfAdjust the PWM pulse width, change the on / off time of the power switch device in the pulse power inverter unit through the pulse power inverter drive circuit, so that the charging capacitor C 202 Perform constant current charging; if U pgg =U pf The pulse power supply control circuit collects the charging voltage signal U from the pulse power supply voltage sensor. pf Adjust the PWM pulse width to charge the capacitor C 202 Perform constant voltage charging to make the charging capacitor C 202 The stored electrical energy is stable.

[0027] Furthermore, the DSP control system also receives a molten droplet morphology state signal obtained by the host computer through machine vision. When the host computer determines that the molten droplet can be separated from the wire end and transferred to the metal substrate, the host computer outputs a molten droplet transfer enable signal to the DSP control system.

[0028] The DSP control system detects the charging voltage signal U fed back pf Whether the set charging voltage U is reached pgg If it reaches, the DSP control system will give the pulse power supply discharge switch opening signal I pIO , transmitted to the base of the pulse power supply discharge switch through the pulse power supply discharge switch driving circuit, so that the pulse power supply discharge switch is turned on;

[0029] During the period when the pulse power supply discharge switch is turned on, the DSP control system makes the charging voltage U pgg When the signal is zero, the pulse power supply control circuit does not output the PWM signal, and the power switch device in the pulse power supply inverter unit does not work; when the discharge is completed, the DSP control system makes the charging voltage U pgg The signal returns to the set value.

[0030] Further, the electrostatic field power supply includes: an electrostatic field power supply anti-reverse connection unit, an electrostatic field power supply inverter unit, an electrostatic field power supply transformer unit, an electrostatic field power supply rectifier circuit, an electrostatic field power supply control circuit, and an electrostatic field power supply inverter drive circuit;

[0031] The input of the anti-reverse connection unit of the electrostatic field power supply is a DC power supply. The anti-reverse connection unit of the electrostatic field power supply includes a diode D 301 、Diode D 302 、Inductance L 301 , capacitor C 301 , where diode D 301 The anode of the diode D is connected to the positive terminal of the DC power supply. 301 The cathode connection inductance L 301 One end of the diode D 302 The cathode of the diode D is connected to the negative terminal of the DC power supply. 302 The anode connection capacitance C301 One end of the capacitor C 301 The other end of the inductor L 301 Not with diode D 301 One end of the connection;

[0032] The output end of the electrostatic field power supply anti-reverse connection unit is connected to the electrostatic field power supply inverter unit, which is a bridge circuit composed of power switching devices; the output end of the electrostatic field power supply inverter unit is connected to the transformer T of the electrostatic field power supply transformer unit 30 The primary side of the transformer T 30 The two ends of the secondary side are connected to the diode D 31 , D 32 , D 33 , D 34 The input end of the electrostatic field power rectifier circuit composed of;

[0033] The positive output terminal of the electrostatic field power rectifier circuit is grounded; the negative output terminal of the electrostatic field power rectifier circuit is connected to the filter inductor L 302 One end of the filter inductor L 302 The other end of the filter inductor L 303 One end of the filter inductor L 303 The other end of the 301 Connected to the electrostatic field terminal; filter inductor L 302 Connected with filter inductor L 303 The common connection point is connected to the filter capacitor C 302 One end of the filter capacitor C 302 The other end is grounded.

[0034] Furthermore, the filter capacitor C 302 The two ends of the electrostatic field power supply voltage sensor are connected in parallel, and the electrostatic field power supply voltage sensor collects the electrostatic field voltage signal U dcf Transmitted to the electrostatic field power control circuit;

[0035] The electrostatic field power supply control circuit converts the U given by the DSP control system into dcgg with U dcf Perform PID regulation to adjust the output PWM pulse width, and control the on / off time of the power switch device in the electrostatic field power inverter unit through the electrostatic field power inverter drive circuit, so as to maintain a stable voltage at the electrostatic field terminal; U dcgg is the given signal U of the electrostatic field voltage from the external circuit dcg The signal obtained after digital filtering.

[0036] The present application also provides a forming process control method for a space additive manufacturing electron gun, comprising:

[0037] The host computer receives the start command of additive manufacturing and transmits the start command to the DSP control system. The DSP control system starts the operation according to the high voltage given signal U hvg With the high voltage feedback signal U hvf Perform PID adjustment and output U hvgg The signal is sent to the high-voltage DC power supply control circuit, so that the working voltage of the annular cathode connected to the output end of the high-voltage power supply reaches the set value;

[0038] The DSP control system is based on the beam current given by I bg and beam feedback I bf Perform PID adjustment and convert it into a gas flow given signal U ggas Transmitted to the gas flow controller, the gas flow controller converts the gas flow signal U gas The gas is transmitted to the gas flow meter, which transmits the working gas to the electron gun chamber through the gas guide tube to adjust the beam size;

[0039] DSP control system turns on the pulse power supply discharge switch signal I pIO The pulse power supply discharge switch is not turned on; the DSP control system is based on the pulse current given signal I pg , by querying the current-voltage conversion parameter table, the corresponding charging voltage signal U pgg , the DSP control system transmits it to the pulse power supply control circuit to control the charging capacitor C 202 Maximum charging voltage;

[0040] The DSP control system receives the electrostatic field voltage given signal U from the external circuit dcg , after digital filtering, the output is U dcgg To the electrostatic field power control circuit, so that the voltage of the electrostatic field terminal reaches the set value;

[0041] The host computer controls the wire feeding mechanism to feed the metal wire at a preset speed. The metal wire is heated and melted at the convergence point of the annular electron beam. The molten metal forms droplets under the action of surface tension. The droplet morphology state signal obtained by machine vision is transmitted to the host computer.

[0042] If the host computer determines that the three-dimensional size of the molten droplet reaches the preset value, it outputs a molten droplet transition enable signal to the DSP control system. The DSP control system detects the feedback charging voltage signal U pf Whether the set charging voltage U is reached pgg ;

[0043] If U pf When the set value is reached, the DSP control system gives a pulse power supply discharge switch opening signal I pIO The signal is high level, making the pulse power supply discharge switch conduction; at the same time, the DSP control system makes the charging voltage Upgg The signal is zero until the discharge is finished, and the DSP control system gives the pulse power supply discharge switch opening signal I pIO The signal is low level, so that the pulse power supply discharge switch is turned off; the DSP control system makes the charging voltage U pgg The signal returns to the set value;

[0044] After the molten droplet transfers to the metal substrate, the host computer moves the electron gun to the next deposition point according to the preset trajectory and repeats the above steps until the formation is completed according to the preset model.

[0045] Furthermore, it also includes:

[0046] The host computer sends a stop signal to the wire feeding mechanism to stop feeding the metal wire. The host computer sends an end command to the DSP control system, and the DSP control system outputs U hvgg The signal is low level, making the high voltage power supply output zero;

[0047] DSP control system enables U ggas The gas flow controller is turned off, and the DSP control system turns on the pulse power supply discharge switch. pIO The pulse power supply discharge switch is not turned on, and the DSP control system makes the charging voltage signal U pgg is zero, so that the pulse power supply does not work, and the DSP control system makes U dcgg is zero, making the electrostatic field power supply inoperative.

[0048] The power supply device and forming process control method of the space additive manufacturing electron gun provided in the present application, under microgravity conditions, since the metal molten droplet is negatively charged, the electrostatic field terminal is negatively charged, and there is a negative electric field between the electrostatic field terminal and the substrate, the molten droplet is constrained by the electrostatic field force and can grow controllably, and will not climb in the opposite direction along the wire or float around; at the same time, under the action of the electric field force, the transition of the metal molten droplet to the metal substrate can be accelerated; when the molten droplet contacts the substrate, a loop is formed between the metal substrate-molten droplet-wire-metal wire reel-metal wire reel support-pulse current source, and the large pulse current applied to the wire generates an electromagnetic force from a small cross-section to a large cross-section at the necking point where the wire and the molten droplet are connected, which can further promote the molten droplet transition, and the molten droplet transition rate can be controlled by adjusting the pulse current amplitude. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 A schematic diagram of a power supply device for an electron gun for space additive manufacturing provided for this application;

[0051] Figure 2 A schematic diagram of a high voltage power supply provided for this application;

[0052] Figure 3 A schematic diagram of a pulse power supply provided for this application;

[0053] Figure 4 A schematic diagram of an electrostatic field power supply provided for this application;

[0054] Figure 5 A flow chart of the forming process control method of the space additive manufacturing electron gun provided in this application.

[0055] Figure numerals: 1. high voltage power supply; 101. high voltage power supply anti-reverse connection unit; 102. high voltage power supply first inverter unit; 103. high voltage power supply first transformer unit; 104. high voltage power supply first rectifier circuit; 105. high voltage power supply second inverter unit; 106. high voltage power supply second transformer unit; 107. high voltage power supply second rectifier circuit; 108. high voltage power supply high voltage sampling circuit; 109. high voltage power supply voltage sensor; 110. high voltage DC power supply control circuit; 111. high voltage power supply first inverter drive circuit; 112. high voltage inverter power supply control circuit; 113. high voltage power supply second inverter drive circuit; 2. pulse power supply; 201. pulse power supply anti-reverse connection unit; 202. pulse power supply inverter unit; 203. pulse power supply transformer unit; 204. pulse power supply rectifier circuit; 205. pulse power supply discharge switch; 206. pulse power supply Discharge switch driving circuit; 207, pulse power supply voltage sensor; 208, pulse power supply current sensor; 209, pulse power supply control circuit; 210, pulse power supply inverter driving circuit; 3, electrostatic field power supply; 301, electrostatic field power supply anti-reverse connection unit; 302, electrostatic field power supply inverter unit; 303, electrostatic field power supply transformer unit; 304, electrostatic field power supply rectifier circuit; 305, electrostatic field power supply voltage sensor; 306, electrostatic field power supply control circuit; 307, electrostatic field power supply inverter driving circuit; 4, DSP control system; 5, gas flow controller; 51, gas flow meter; 6, annular cathode; 7, electrostatic field terminal; 8, electron gun chamber; 9, metal substrate; 10, metal wire coil bracket; 11, metal wire coil; 12, metal wire material; 13, electron beam; 14, metal droplet; 15, anode; 16, air guide tube; 17, host computer. DETAILED DESCRIPTION

[0056] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0057] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0058] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0059] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0060] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0061] like Figure 1 As shown, this embodiment provides a power supply device for a space additive manufacturing electron gun, which mainly includes: a high-voltage power supply 1, a pulse power supply 2, an electrostatic field power supply 3, a DSP control system 4, a gas flow controller 5, and a host computer 17.

[0062] like Figure 2As shown, the high-voltage power supply 1 includes: a high-voltage power supply anti-reverse connection unit 101, a high-voltage power supply first inverter unit 102, a high-voltage power supply first transformer unit 103, a high-voltage power supply first rectifier circuit 104, a high-voltage power supply second inverter unit 105, a high-voltage power supply second transformer unit 106, a high-voltage power supply second rectifier circuit 107, a high-voltage power supply high-voltage sampling circuit 108, a high-voltage power supply voltage sensor 109, a high-voltage power supply control circuit 110, a high-voltage power supply first inverter drive circuit 111, a high-voltage inverter power supply control circuit 112, and a high-voltage power supply second inverter drive circuit 113.

[0063] The input of the high-voltage power supply reverse connection protection unit 101 is DC 100V. The high-voltage power supply reverse connection protection unit 101 is composed of a diode D0, a diode D1, an inductor L0, and a capacitor C0, wherein the anode of the diode D0 is connected to the positive end of the DC 100V, and the cathode of the diode D0 is connected to one end of the inductor L0; the cathode of the diode D1 is connected to the negative end of the DC 100V, the anode of the diode D1 is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to the end of the inductor L0 that is not connected to the diode D0, and the inductor L0 and the capacitor C0 form an LC filter circuit; the connection method of the diode D0, the diode D1 and the positive and negative ends of the DC 100V power supply of the high-voltage power supply reverse connection protection unit 101 can avoid damage to the DC 100V power supply due to operational errors.

[0064] The output end of the high-voltage power supply reverse connection protection unit 101 is connected to the high-voltage power supply first inverter unit 102, which is a full-bridge circuit composed of power switching devices; the output end of the high-voltage power supply first inverter unit 102 is connected to the power transformer T of the high-voltage power supply first transformer unit 103. 10 The primary side of the power transformer T 10 The primary-to-secondary transformation ratio is 1:6, and the power transformer T of the first transformer unit 103 of the high-voltage power supply is 10 The secondary side is connected to the input end of the high-voltage power supply first rectifier circuit 104; the output end of the high-voltage power supply first rectifier circuit 104 is connected in parallel with the high-voltage power supply voltage sensor 109. The high-voltage power supply voltage sensor 109 detects that the high-voltage power supply first rectifier circuit 104 outputs a voltage signal U f , will U f Feedback to the high voltage power supply control circuit 110.

[0065] The output end of the first rectifier circuit 104 of the high-voltage power supply is connected to the second inverter unit 105 of the high-voltage power supply, which is also a full-bridge circuit composed of power switching devices; the gates of each power switching device in the full-bridge circuit are respectively connected to the second inverter drive circuit 113 of the high-voltage power supply, which receives the PWM signal from the high-voltage inverter control circuit 112 to control each power switching device in the full-bridge circuit of the second inverter unit 105 of the high-voltage power supply to be turned on at full frequency and full pulse width.

[0066] The output end of the high-voltage power supply second inverter unit 105 is connected to the high-voltage power supply second transformer unit 106. The high-voltage power supply second transformer unit 106 is composed of two high-voltage transformers T 11 、T 12 Composition, high voltage transformer T 11 、T 12 The primary side of the high voltage transformer T is connected in parallel to the output end of the second inverter unit 105 of the high voltage power supply; 11 、T 12 The transformation ratio of the primary side to the secondary side is 1:27. The high-voltage transformer T 11 The two ends of the secondary side are connected to the high voltage diode D 11 , D 12 , D 13 , D 14 Points A and B that make up the rectifier bridge; high-voltage transformer T 12 The two ends of the secondary side are connected to the high voltage diode D 15 , D 16 , D 17 , D 18 Points E and F form the rectifier bridge.

[0067] High voltage diode D 11 , D 12 , D 13 , D 14 The positive end of the rectifier bridge and the high-voltage diode D 15 , D 16 , D 17 , D 18 The negative end of the rectifier bridge is connected to point O; the high voltage diode D 11 , D 12 , D 13 , D 14 The rectifier bridge and high voltage diode D 15 , D 16 , D 17 , D 18 The composed rectifier bridge together constitutes the second rectifier circuit 107 of the high voltage power supply.

[0068] The negative output terminal of the second rectifier circuit 107 of the high-voltage power supply is connected to the annular cathode 6; the positive output terminal of the second rectifier circuit 107 of the high-voltage power supply is connected to one end of the beam sampling resistor R1, and the beam sampling signal I bf Take it out from this end of the beam current sampling resistor R1, and the other end of the beam current sampling resistor R1 is connected to the reference ground.

[0069] A high-voltage power supply high-voltage sampling circuit 108 is connected in parallel between the negative output terminal and the positive output terminal of the high-voltage power supply second rectifier circuit 107. The high-voltage power supply high-voltage sampling circuit 108 is composed of a voltage dividing resistor R a1 , R a2 , ... and high-voltage sampling resistor R0; voltage divider resistor R a1 , R a2 , ... are connected in series with the high-voltage sampling resistor R0, and the voltage divider resistor R a1 , R a2 , ... and the high-voltage sampling resistor R0 connection point to collect the high-voltage feedback signal U hvf The other end of the high-voltage sampling resistor R0 is connected to the positive output end of the second rectifier circuit 107 of the high-voltage power supply.

[0070] High voltage feedback signal U hvf Feedback to the DSP control system 4, DSP control system 4 according to the high voltage given signal U hvg With the high voltage feedback signal U hvf Perform PID adjustment and output U hvgg The signal is sent to the high-voltage DC power supply control circuit 110, and the high-voltage DC power supply control circuit 110 simultaneously receives the output voltage signal U from the high-voltage power supply voltage sensor 109 detecting that the high-voltage power supply first rectifier circuit 104 outputs the voltage signal U f , U f with U hvgg After PID adjustment by the high-voltage DC power supply control circuit 110, the output PWM signal pulse width is adjusted, and then after passing through the high-voltage power supply first inverter drive circuit 111, four PWM signals are output to the gates of each power switch device in the full-bridge circuit of the high-voltage power supply first inverter unit 102, and the conduction time of the corresponding power switch device is adjusted, thereby adjusting the output voltage of the high-voltage power supply first rectifier circuit 104; and then adjusting the output voltage of the high-voltage power supply second rectifier circuit 107, that is, adjusting the negative high voltage output by the high-voltage power supply 1 to the annular cathode 6.

[0071] like Figure 3 As shown, the pulse power supply 2 is mainly composed of a pulse power supply anti-reverse connection unit 201, a pulse power supply inverter unit 202, a pulse power supply transformer unit 203, a pulse power supply rectifier circuit 204, a pulse power supply discharge switch 205, a pulse power supply discharge switch drive circuit 206, a pulse power supply voltage sensor 207, a pulse power supply current sensor 208, and a filter inductor L 202, charging capacitor C 202 , a pulse power supply control circuit 209, and a pulse power supply inverter drive circuit 210.

[0072] The pulse power supply reverse connection protection unit 201 input is DC 100V, and the pulse power supply reverse connection protection unit 201 is composed of a diode D 201 、Diode D 202 、Inductance L 201 , capacitor C 201 Composition, where diode D 201 The anode of the diode D is connected to the positive terminal of the DC 100V. 201 The cathode connection inductance L 201 One end of the diode D 202 The cathode of the diode D is connected to the negative end of the DC 100V. 202 The anode connection capacitance C 201 One end of the capacitor C 201 The other end of the inductor L 201 Not with diode D 201 Connect one end of the inductor L 201 , capacitor C 201 Composed of LC filter circuit; diode D of pulse power supply anti-reverse connection unit 201 201 、Diode D 202 The connection method with the positive and negative terminals of the DC 100V power supply can avoid damage to the DC 100V power supply due to operating errors.

[0073] The output end of the pulse power supply anti-reverse connection unit 201 is connected to the pulse power supply inverter unit 202, which is a bridge circuit composed of power switching devices; the output end of the pulse power supply inverter unit 202 is connected to the transformer T of the pulse power supply transformer unit 203 20 The primary side of the transformer T 20 The primary-to-secondary ratio is 1:12, and the transformer T of the pulse power transformer unit 203 20 The two ends of the secondary side are connected to the diode D 21 , D 22 , D 23 , D 24 The A1 and B1 input terminals of the electrostatic field power rectifier circuit 204 are composed.

[0074] The negative output terminal of the pulse power rectifier circuit 204 is connected to the filter inductor L 202 One end of the filter inductor L 202 The other end is connected in series with the pulse power supply current sensor 208 and then connected to the charging capacitor C 202 One end of the charging capacitor C 202The other end is connected to the positive output end of the pulse power rectifier circuit 204; the positive output end of the pulse power rectifier circuit 204 is also connected to the current limiting resistor R 201 One end of the current limiting resistor R 201 The other end is connected to the reference ground.

[0075] Filter inductor L 202 With charging capacitor C 202 The common point of connection is connected to the emitter of the pulse power supply discharge switch 205, which is composed of a single high-power IGBT or multiple IGBTs connected in parallel. The collector of the pulse power supply discharge switch 205 is connected to the wire coil support 10; the wire coil support 10 is insulated from the reference ground.

[0076] Charging capacitor C 202 The two ends of the pulse power supply are also connected in parallel to the pulse power supply voltage sensor 207. When the pulse power supply discharge switch 205 is not turned on, the pulse power supply voltage sensor 207 collects the charging voltage signal U pf Feedback to the pulse power supply control circuit 209, the pulse power supply control circuit 209 gives the DSP control system 4 a charging voltage signal U pgg with U pf For comparison, if U pgg >U pf The pulse power supply control circuit 209 generates a charging current signal I according to the pulse power supply current sensor 208. pf Adjust the PWM pulse width, change the on / off time of the power switch device in the pulse power inverter unit 202 through the pulse power inverter drive circuit 210, so that the charging capacitor C 202 Perform constant current charging; if U pgg =U pf The pulse power supply control circuit 209 generates a charging voltage signal U according to the pulse power supply voltage sensor 209. pf Adjust the PWM pulse width to charge the capacitor C 202 Perform constant voltage charging to make the charging capacitor C 202 The stored electrical energy is stable.

[0077] Charging capacitor C 202 The capacity is not less than 2000μF, and the withstand voltage level is not less than 2000V; the current limiting resistor R 201 The resistance value is not greater than 1Ω.

[0078] When the pulse power supply discharge switch 205 is turned on, the pulse current flows from the charging capacitor C 202 One end of the pulse power supply discharge switch 205, the metal wire disc support 10, the metal wire disc 11, the metal wire material 12, the molten drop 14, the metal substrate 9, the current limiting resistor R 201 After that, it flows to the charging capacitor C 202At the other end, the pulse current generates an electromagnetic force from a small cross section to a large cross section at the necking point where the metal wire 12 and the molten droplet 14 are connected, which will promote the transition of the molten droplet 14.

[0079] The charging capacitor C 202 When the capacitance value is determined, the internal resistance of the pulse power supply discharge switch 205, the resistance of the metal wire disc support 10 and the metal wire disc 11, the resistance of the metal wire material 12 and the molten droplet 14, the metal substrate 9 and the current limiting resistor R 201 When the resistance value remains unchanged, the pulse current is determined by the charging capacitor C 202 The maximum charging voltage is determined by a series of tests to obtain the pulse current and charging capacitor C 202 The voltage corresponds to the current-voltage conversion parameter table, which is stored in the DSP control system 4. The DSP control system 4 generates a pulse current given signal I pg , by querying the current-voltage conversion parameter table, the corresponding charging voltage signal U pgg , the DSP control system 4 transmits it to the pulse power supply control circuit 209, which determines the charging capacitor C 202 The maximum charging voltage determines the pulse current size.

[0080] The DSP control system 4 also receives a molten droplet morphology state signal obtained by the host computer 17 through machine vision. When the host computer 17 determines that the molten droplet 14 can be separated from the wire end and transferred to the metal substrate 9, the host computer 17 outputs a molten droplet transfer enable signal to the DSP control system 4. The DSP control system 4 detects the feedback charging voltage signal U pf Whether the set charging voltage U is reached pgg If not reached, wait for U pf Reach the set charging voltage U pgg ; U pf When the set value is reached, the DSP control system 4 gives a pulse power supply discharge switch 205 opening signal I pIO , transmitted to the base of the pulse power supply discharge switch 205 through the pulse power supply discharge switch driving circuit 206, so that the pulse power supply discharge switch 205 is turned on, and the conduction time t>1 / 2(RC), R is the internal resistance of the pulse power supply discharge switch 205, the resistance of the metal wire coil support 10 and the metal wire coil 11, the resistance of the metal wire material 12 and the molten droplet 14, the metal substrate 9 and the current limiting resistor R 201 The sum of resistance values; C is the charging capacitor C 202 Capacitance value.

[0081] During the period when the pulse power supply discharge switch 205 is turned on, the DSP control system 4 makes the charging voltage U pggThe signal is zero, then the pulse power supply control circuit 209 does not output the PWM signal, and the power switch device in the pulse power supply inverter unit 202 does not work; when the discharge is completed, the DSP control system 4 makes the charging voltage U pgg The signal returns to the set value.

[0082] like Figure 4 As shown, the electrostatic field power supply 3 is mainly composed of an electrostatic field power supply anti-reverse connection unit 301, an electrostatic field power supply inverter unit 302, an electrostatic field power supply transformer unit 303, an electrostatic field power supply rectifier circuit 304, an electrostatic field power supply voltage sensor 305, an electrostatic field power supply control circuit 306, and an electrostatic field power supply inverter drive circuit 307.

[0083] The input of the electrostatic field power supply reverse connection protection unit 301 is a DC 100V, and the electrostatic field power supply reverse connection protection unit 301 is composed of a diode D 301 、Diode D 302 、Inductance L 301 , capacitor C 301 Composition, where diode D 301 The anode of the diode D is connected to the positive terminal of the DC 100V. 301 The cathode connection inductance L 301 One end of the diode D 302 The cathode of the diode D is connected to the negative end of the DC 100V. 302 The anode connection capacitance C 301 One end of the capacitor C 301 The other end of the inductor L 301 Not with diode D 301 Connect one end of the inductor L 301 , capacitor C 301 Composed of LC filter circuit; diode D of pulse power supply anti-reverse connection unit 301 301 、Diode D 302 The connection method with the positive and negative terminals of the DC 100V power supply can avoid damage to the DC 100V power supply due to operating errors.

[0084] The output end of the electrostatic field power supply anti-reverse connection unit 301 is connected to the electrostatic field power supply inverter unit 302, which is a bridge circuit composed of power switching devices; the output end of the electrostatic field power supply inverter unit 302 is connected to the transformer T of the electrostatic field power supply transformer unit 303 30 The primary side of the transformer T 30 The primary-to-secondary ratio of the transformer is 5:6. 30 The two ends of the secondary side are connected to the diode D 31 , D 32 , D 33 , D 34The A2 and B2 input terminals of the electrostatic field power rectifier circuit 304 are composed of the electrostatic field power rectifier circuit 304; the positive output terminal of the electrostatic field power rectifier circuit 304 is also connected to the reference ground; the negative output terminal of the electrostatic field power rectifier circuit 304 is connected to the filter inductor L 302 One end of the filter inductor L 302 The other end of the filter inductor L 303 One end of the filter inductor L 303 The other end of the 301 Connected to the electrostatic field terminal 7; filter inductor L 302 Connected with filter inductor L 303 The common connection point is connected to the filter capacitor C 302 One end of the filter capacitor C 302 The other end is connected to the reference ground; the filter inductor L 302 、Filter inductor L 303 、Filter capacitor C 302 Form a "T" type filter circuit.

[0085] The filter capacitor C 302 The two ends of the electrostatic field power supply voltage sensor 305 are connected in parallel, and the electrostatic field power supply voltage sensor 305 collects the electrostatic field voltage signal U dcf The U signal received from the DSP control system 4 is transmitted to the electrostatic field power supply control circuit 306, which receives the U signal received from the DSP control system 4. dcgg with U dcf PID regulation is performed to adjust the output PWM pulse width, and the on / off time of the power switch device in the electrostatic field power inverter unit 302 is controlled by the electrostatic field power inverter drive circuit 307, so that the electrostatic field terminal 7 maintains a stable voltage.

[0086] The electrostatic field terminal 7 is negatively charged. When the molten droplet 14 has not yet transitioned to the substrate, the surface of the molten droplet 14 carries a large amount of negative charge. The electrostatic field terminal 7 repels the molten droplet 14, preventing the molten droplet 14 from climbing up along the metal wire 12 in the reverse direction and promoting the controllable deposition of the molten droplet 14 toward the metal substrate 9. dcgg is the given signal U of the electrostatic field voltage from the external circuit dcg The signal obtained after digital filtering.

[0087] like Figure 5 As shown, this embodiment also provides a forming process control method for a space additive manufacturing electron gun, which is detailed as follows:

[0088] Step 1 S001, multi-parameter presetting: The host computer 17 receives the additive manufacturing start instruction according to the human-computer interaction interface, and transmits the operation start instruction to the DSP control system 4. The DSP control system 4 hvg With the high voltage feedback signal U hvfPerform PID adjustment and output U hvgg The signal is sent to the high-voltage DC power supply control circuit 110, so that the working voltage of the annular cathode 6 connected to the output end of the high-voltage power supply 1 reaches a set value.

[0089] DSP control system 4 is based on the beam current given I bg and beam feedback I bf Perform PID adjustment and convert it into a gas flow given signal U ggas The gas flow controller 5 transmits the gas flow signal Ugas to the gas flow meter 51, and the gas flow meter 51 transmits the working gas to the electron gun chamber 8 through the gas guide tube 16, and adjusts the amount of working gas entering the electron gun chamber 8, so as to achieve the purpose of adjusting the beam size.

[0090] DSP control system 4 turns on pulse power supply discharge switch 205 signal I pIO is low level, the pulse power supply discharge switch 205 is not turned on; the DSP control system 4 is based on the pulse current given signal I pg , by querying the current-voltage conversion parameter table, the corresponding charging voltage signal U pgg , the DSP control system 4 transmits it to the pulse power supply control circuit 209 to control the charging capacitor C 202 The maximum charging voltage; change the pulse current given signal I pg , that is, the charging capacitor C is changed 202 The maximum charging voltage changes the pulse current accordingly.

[0091] The DSP control system 4 receives the electrostatic field voltage given signal U from the external circuit dcg , after digital filtering, the output is U dcgg To the electrostatic field power supply control circuit 306, so that the voltage of the electrostatic field terminal 7 reaches the set value.

[0092] Step 2 S002, directional melting of wire: the upper computer 17 controls the wire feeding mechanism to feed the metal wire 12 at a preset speed. The metal wire 12 is heated and melted at the convergence point of the annular electron beam, and the molten metal forms a molten droplet 14 under the action of surface tension. As the metal wire 12 is fed and melted, the molten droplet 14 gradually grows within the constraint range of the electric field force under the action of the electrostatic field force, thereby avoiding the uncontrollable phenomenon of the molten droplet 14 climbing in the opposite direction along the metal wire 12 and being disturbed and drifting.

[0093] Step 3 S003, molten droplet transition determination: The molten droplet morphology state signal obtained by machine vision is transmitted to the host computer 17, and the host computer 17 determines whether the three-dimensional size of the molten droplet has reached a transition state. If the three-dimensional size of the molten droplet has not reached the preset value, the detection and determination will continue.

[0094] Step 4 S004, controlled droplet transition: The host computer 17 determines that the three-dimensional size of the droplet reaches a preset value, and the host computer 17 outputs a droplet transition enable signal to the DSP control system 4. The DSP control system 4 detects the feedback charging voltage signal U pf Whether the set charging voltage U is reached pgg If not reached, wait for U pf Reach the set charging voltage U pgg ; U pf When the set value is reached, the DSP control system 4 gives a pulse power supply discharge switch 205 opening signal I pIO The signal is high level, so that the pulse power supply discharge switch 205 is turned on and maintained for the on time t; at the same time, the DSP control system 4 makes the charging voltage U pgg The signal is zero until the discharge is finished, and the DSP control system 4 gives the pulse power supply discharge switch 205 an opening signal I pIO The signal is at a low level, so that the pulse power supply discharge switch 205 is turned off; the DSP control system 4 makes the charging voltage U pgg The signal returns to the set value.

[0095] Step 5 S005, forming according to a preset trajectory: After the molten droplet 14 transitions to the metal substrate 9, the host computer 17 moves the electron gun to the next deposition point according to the preset trajectory, and repeats steps 2 to 5 until the forming is completed according to the preset model.

[0096] Step 6 S006, end of operation: the host computer 17 sends a stop signal to the wire feeding mechanism to stop feeding the metal wire 12; the host computer 17 sends an end of operation command to the DSP control system 4, and the DSP control system 4 outputs U hvgg The signal is low level, making the output of high voltage power supply 1 zero; DSP control system 4 makes U ggas is zero, the gas flow controller 5 is turned off; the DSP control system 4 turns on the pulse power supply discharge switch 205 signal I pIO is low level, the pulse power supply discharge switch 205 is not turned on; the DSP control system 4 makes the charging voltage signal U pgg is zero, so that the pulse power supply 2 does not work; the DSP control system 4 makes U dcgg is zero, making the electrostatic field power supply 3 inoperative.

[0097] The power supply device and forming process control method of the space additive manufacturing electron gun provided in the embodiment of the present application can provide a negative high voltage of -20kV to -10kV to the cathode to excite and accelerate secondary electrons, thereby melting the wire located in the electron beam energy convergence area; according to the wire end status information provided by the wire end position monitoring closed-loop control system, the pulse current source connected to the wire is controlled to operate, and a peak pulse current of 100A to 1000A is input to regulate the droplet transition rate; at the same time, a DC voltage of -100V to -24V is provided for the electrostatic field at the end of the electron gun to accelerate the transition of the droplet to the substrate; through the above method, the requirements for efficient, high-quality and rapid manufacturing of a wire bundle coaxial cold cathode electron gun in a space environment can be met.

[0098] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0099] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A power supply device for an electron gun for space additive manufacturing, characterized in that: include: High voltage power supply, pulse power supply, electrostatic field power supply, DSP control system, gas flow controller, host computer; The negative electrode of the high-voltage power supply is connected to the annular cathode, and the positive electrode of the high-voltage power supply is connected to the metal substrate through the beam sampling resistor; the negative electrode of the pulse power supply is connected to the metal wire coil support, and the positive electrode of the pulse power supply is grounded; the negative electrode of the electrostatic field power supply is connected to the electrostatic field terminal, and the positive electrode of the electrostatic field power supply is grounded; the DSP control system is respectively connected to the high-voltage power supply, the pulse power supply, the electrostatic field power supply, the gas flow controller, and the host computer; the gas flow controller is connected to the electron gun chamber; The DSP control system is used to: receive the operation start instruction of the host computer; control the output voltage of the high-voltage power supply to adjust the beam size in the electron beam energy convergence area; control the output pulse current of the pulse power supply to regulate the droplet transition rate; control the output voltage of the electrostatic field power supply to accelerate the transition of the droplet to the substrate; control the gas flow output by the gas flow controller to adjust the beam size.

2. The power supply device for the electron gun for space additive manufacturing according to claim 1, characterized in that: The high-voltage power supply includes: a high-voltage power supply anti-reverse connection unit, a high-voltage power supply first inverter unit, a high-voltage power supply first transformer unit, a high-voltage power supply first rectifier circuit, a high-voltage power supply second inverter unit, a high-voltage power supply second transformer unit, a high-voltage power supply second rectifier circuit, a high-voltage power supply voltage sensor, a high-voltage DC power supply control circuit, a high-voltage power supply first inverter drive circuit, a high-voltage inverter power supply control circuit, and a high-voltage power supply second inverter drive circuit; The input of the high-voltage power supply reverse connection protection unit is a DC power supply, and the high-voltage power supply reverse connection protection unit includes a diode D0, a diode D1, an inductor L0, and a capacitor C0, wherein the anode of the diode D0 is connected to the positive end of the DC power supply, and the cathode of the diode D0 is connected to one end of the inductor L0; the cathode of the diode D1 is connected to the negative end of the DC power supply, the anode of the diode D1 is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to the end of the inductor L0 that is not connected to the diode D0; The output end of the high-voltage power supply anti-reverse connection unit is connected to the first inverter unit of the high-voltage power supply, and the first inverter unit of the high-voltage power supply is a full-bridge circuit composed of power switching devices; the output end of the first inverter unit of the high-voltage power supply is connected to the power transformer T of the first transformer unit of the high-voltage power supply 10 The primary side of the power transformer T 10 The secondary side is connected to the input end of the first rectifier circuit of the high-voltage power supply; the output end of the first rectifier circuit of the high-voltage power supply is connected in parallel with a high-voltage power supply voltage sensor; the high-voltage power supply voltage sensor detects the output voltage signal U of the first rectifier circuit of the high-voltage power supply f , will U f Feedback to the high voltage DC power supply control circuit; The output end of the first rectifier circuit of the high-voltage power supply is connected to the second inverter unit of the high-voltage power supply; the second inverter unit of the high-voltage power supply is also a full-bridge circuit composed of power switching devices, and the gates of each power switching device are respectively connected to the second inverter drive circuit of the high-voltage power supply, and the second inverter drive circuit of the high-voltage power supply receives a PWM signal from the high-voltage inverter power supply control circuit to control each power switching device to be turned on at full frequency and full pulse width; The second rectifier circuit of the high voltage power supply includes a high voltage diode D 11 , D 12 , D 13 , D 14 The rectifier bridge and high voltage diode D 15 , D 16 , D 17 , D 18 The rectifier bridge consists of the high voltage diode D 11 , D 12 , D 13 , D 14 The positive end of the rectifier bridge and the high voltage diode D 15 , D 16 , D 17 , D 18 The negative terminal of the rectifier bridge is connected; The output end of the second inverter unit of the high-voltage power supply is connected to the second transformer unit of the high-voltage power supply, and the second transformer unit of the high-voltage power supply includes two high-voltage transformers T 11 , T 12 , the high voltage transformer T 11 , T 12 The primary side is connected in parallel to the output end of the second inverter unit of the high-voltage power supply, and the high-voltage transformer T 11 The two ends of the secondary side are connected to the high voltage diode D 11 , D 12 , D 13 , D 14 The rectifier bridge is composed of the high voltage transformer T 12 The two ends of the secondary side are connected to the high voltage diode D 15 , D 16 , D 17 , D 18 The rectifier bridge is composed of The negative output end of the second rectifier circuit of the high-voltage power supply is connected to the annular cathode; the positive output end of the second rectifier circuit of the high-voltage power supply is connected to one end of the beam sampling resistor R1, and the beam sampling signal I bf Take it out from this end of the beam current sampling resistor R1, and the other end of the beam current sampling resistor R1 is connected to the reference ground.

3. The power supply device for the electron gun for space additive manufacturing as claimed in claim 2, characterized in that: A high-voltage power supply high-voltage sampling circuit is connected in parallel between the negative output terminal and the positive output terminal of the second rectifier circuit of the high-voltage power supply, and the high-voltage power supply high-voltage sampling circuit includes a plurality of voltage-dividing resistors and a high-voltage sampling resistor R0; the plurality of voltage-dividing resistors and the high-voltage sampling resistor R0 are sequentially connected in series, and a high-voltage feedback signal U is collected at the connection point between the plurality of voltage-dividing resistors and the high-voltage sampling resistor R0. hvf , the other end of the high-voltage sampling resistor R0 is connected to the positive output end of the second rectifier circuit of the high-voltage power supply; The high voltage feedback signal U hvf Feedback to the DSP control system, DSP control system according to the high voltage given signal U hvg With the high voltage feedback signal U hvf Perform PID adjustment and output U hvgg The high-voltage DC power supply control circuit receives the output voltage signal U of the first rectifier circuit of the high-voltage power supply detected by the high-voltage power supply voltage sensor. f ; The U f with U hvgg After PID adjustment by the high-voltage DC power supply control circuit, the output PWM signal pulse width is adjusted, and then after passing through the first inverter drive circuit of the high-voltage power supply, four PWM signals are output to the gates of each power switch device in the full-bridge circuit of the first inverter unit of the high-voltage power supply, and the conduction time of the corresponding power switch device is adjusted, thereby adjusting the output voltage of the first rectifier circuit of the high-voltage power supply and the output voltage of the second rectifier circuit of the high-voltage power supply, so as to adjust the negative high voltage output by the high-voltage power supply to the annular cathode.

4. The power supply device for the electron gun for space additive manufacturing according to claim 1, characterized in that: The pulse power supply comprises: a pulse power supply anti-reverse connection unit, a pulse power supply inverter unit, a pulse power supply transformer unit, a pulse power supply rectifier circuit, a pulse power supply discharge switch, a pulse power supply discharge switch drive circuit, a pulse power supply current sensor, a filter inductor L 202 , charging capacitor C 202 , pulse power supply control circuit, pulse power supply inverter drive circuit; The pulse power supply reverse connection protection unit input is a DC power supply, and the pulse power supply reverse connection protection unit includes a diode D 201 、Diode D 202 、Inductance L 201 , capacitor C 201 , where diode D 201 The anode of the diode D is connected to the positive terminal of the DC power supply. 201 The cathode connection inductance L 201 One end of the diode D 202 The cathode of the diode D is connected to the negative terminal of the DC power supply. 202 The anode connection capacitance C 201 One end of the capacitor C 201 The other end of the inductor L 201 Not with diode D 201 One end of the connection; The output end of the pulse power supply anti-reverse connection unit is connected to the pulse power supply inverter unit, and the pulse power supply inverter unit is a bridge circuit composed of power switching devices; the output end of the pulse power supply inverter unit is connected to the transformer T of the pulse power supply transformer unit 20 The primary side of the transformer T 20 The two ends of the secondary side are connected to the diode D 21 , D 22 , D 23 , D 24 The input end of the pulse power supply rectifier circuit composed of the pulse power supply; The negative output end of the pulse power rectifier circuit is connected to the filter inductor L 202 One end of the filter inductor L 202 The other end is connected in series with the pulse power supply current sensor and then connected to the charging capacitor C 202 One end of the charging capacitor C 202 The other end is connected to the positive output end of the pulse power rectifier circuit; the positive output end of the pulse power rectifier circuit is also connected to the current limiting resistor R 201 One end of the current limiting resistor R 201 The other end is grounded; The filter inductor L 202 With charging capacitor C 202 The common point of connection is connected to the emitter of the pulse power supply discharge switch, which is composed of a single high-power IGBT or multiple IGBTs connected in parallel. The collector of the pulse power supply discharge switch is connected to the wire coil support; the wire coil support is insulated from the ground.

5. The power supply device for the electron gun for space additive manufacturing as claimed in claim 4, characterized in that: The charging capacitor C 202 The two ends of the pulse power supply voltage sensor are connected in parallel. When the pulse power supply discharge switch is not turned on, the pulse power supply voltage sensor collects the charging voltage signal U pf Feedback to the pulse power supply control circuit, the pulse power supply control circuit gives the DSP control system a charging voltage signal U pgg with U pf Make comparisons; If U pgg >U pf The pulse power supply control circuit is based on the charging current signal I collected by the pulse power supply current sensor pf Adjust the PWM pulse width, change the on / off time of the power switch device in the pulse power inverter unit through the pulse power inverter drive circuit, so that the charging capacitor C 202 Carry out constant current charging; If U pgg =U pf The pulse power supply control circuit collects the charging voltage signal U from the pulse power supply voltage sensor. pf Adjust the PWM pulse width to charge the capacitor C 202 Perform constant voltage charging to make the charging capacitor C 202 The stored electrical energy is stable.

6. The power supply device for the electron gun for space additive manufacturing as claimed in claim 5, characterized in that: The DSP control system also receives a molten droplet morphology state signal obtained by the host computer through machine vision. When the host computer determines that the molten droplet can be separated from the wire end and transferred to the metal substrate, the host computer outputs a molten droplet transfer enable signal to the DSP control system. The DSP control system detects the charging voltage signal U fed back pf Whether the set charging voltage U is reached pgg If it reaches, the DSP control system will give the pulse power supply discharge switch opening signal I pIO , transmitted to the base of the pulse power supply discharge switch through the pulse power supply discharge switch driving circuit, so that the pulse power supply discharge switch is turned on; During the period when the pulse power supply discharge switch is turned on, the DSP control system makes the charging voltage U pgg When the signal is zero, the pulse power supply control circuit does not output the PWM signal, and the power switch device in the pulse power supply inverter unit does not work; when the discharge is completed, the DSP control system makes the charging voltage U pgg The signal returns to the set value.

7. The power supply device for the electron gun for space additive manufacturing as claimed in claim 1, characterized in that: The electrostatic field power supply comprises: an electrostatic field power supply anti-reverse connection unit, an electrostatic field power supply inverter unit, an electrostatic field power supply transformer unit, an electrostatic field power supply rectifier circuit, an electrostatic field power supply control circuit, and an electrostatic field power supply inverter drive circuit; The input of the electrostatic field power supply reverse connection protection unit is a DC power supply, and the electrostatic field power supply reverse connection protection unit includes a diode D 301 、Diode D 302 、Inductance L 301 , capacitor C 301 , where diode D 301 The anode of the diode D is connected to the positive terminal of the DC power supply. 301 The cathode connection inductance L 301 One end of the diode D 302 The cathode of the diode D is connected to the negative terminal of the DC power supply. 302 The anode connection capacitance C 301 One end of the capacitor C 301 The other end of the inductor L 301 Not with diode D 301 One end of the connection; The output end of the electrostatic field power supply anti-reverse connection unit is connected to the electrostatic field power supply inverter unit, and the electrostatic field power supply inverter unit is a bridge circuit composed of power switching devices; the output end of the electrostatic field power supply inverter unit is connected to the transformer T of the electrostatic field power supply transformer unit 30 The primary side of the transformer T 30 The two ends of the secondary side are connected to the diode D 31 , D 32 , D 33 , D 34 The input end of the electrostatic field power rectifier circuit composed of; The positive output terminal of the electrostatic field power rectifier circuit is grounded; the negative output terminal of the electrostatic field power rectifier circuit is connected to the filter inductor L 302 One end of the filter inductor L 302 The other end of the filter inductor L 303 One end of the filter inductor L 303 The other end of the 301 Connected to the electrostatic field terminal; the filter inductor L 302 Connected with filter inductor L 303 The common connection point is connected to the filter capacitor C 302 One end of the filter capacitor C 302 The other end is grounded.

8. The power supply device for the electron gun for space additive manufacturing as claimed in claim 7, characterized in that: The filter capacitor C 302 The two ends of the electrostatic field power supply voltage sensor are connected in parallel, and the electrostatic field power supply voltage sensor collects the electrostatic field voltage signal U dcf Transmitted to the electrostatic field power control circuit; The electrostatic field power supply control circuit converts the U given by the DSP control system into dcgg with U dcf Perform PID regulation to adjust the output PWM pulse width, and control the on / off time of the power switch device in the electrostatic field power inverter unit through the electrostatic field power inverter drive circuit, so that the electrostatic field terminal maintains a stable voltage; the U dcgg is the given signal U of the electrostatic field voltage from the external circuit dcg The signal obtained after digital filtering.

9. A forming process control method for an electron gun for space additive manufacturing, characterized in that: include: The host computer receives the additive manufacturing start command and transmits the operation start command to the DSP control system. The DSP control system starts the operation according to the high voltage given signal U hvg With the high voltage feedback signal U hvf Perform PID adjustment and output U hvgg The signal is sent to the high-voltage DC power supply control circuit, so that the working voltage of the annular cathode connected to the output end of the high-voltage power supply reaches the set value; The DSP control system is based on the beam current given by I bg and beam feedback I bf Perform PID adjustment and convert it into a gas flow given signal U ggas Transmitted to the gas flow controller, the gas flow controller converts the gas flow signal U gas The gas is transmitted to the gas flow meter, which transmits the working gas to the electron gun chamber through the gas guide tube to adjust the beam size; DSP control system turns on the pulse power supply discharge switch signal I pIO It is low level, and the pulse power supply discharge switch is not turned on; The DSP control system is based on the pulse current given signal I pg , by querying the current-voltage conversion parameter table, the corresponding charging voltage signal U pgg , the DSP control system transmits it to the pulse power supply control circuit to control the charging capacitor C 202 Maximum charging voltage; The DSP control system receives the electrostatic field voltage given signal U from the external circuit dcg , after digital filtering, the output is U dcgg To the electrostatic field power control circuit, so that the voltage of the electrostatic field terminal reaches the set value; The host computer controls the wire feeding mechanism to feed the metal wire at a preset speed. The metal wire is heated and melted at the convergence point of the annular electron beam. The molten metal forms droplets under the action of surface tension. The droplet morphology state signal obtained by machine vision is transmitted to the host computer. If the host computer determines that the three-dimensional size of the molten droplet reaches the preset value, it outputs a molten droplet transition enable signal to the DSP control system. The DSP control system detects the feedback charging voltage signal U pf Whether the set charging voltage U is reached pgg ; If U pf When the set value is reached, the DSP control system gives a pulse power supply discharge switch opening signal I pIO The signal is high level, making the pulse power supply discharge switch conduction; at the same time, the DSP control system makes the charging voltage U pgg The signal is zero until the discharge is finished, and the DSP control system gives the pulse power supply discharge switch opening signal I pIO The signal is low level, so that the pulse power supply discharge switch is turned off; the DSP control system makes the charging voltage U pgg The signal returns to the set value; After the molten droplet transfers to the metal substrate, the host computer moves the electron gun to the next deposition point according to the preset trajectory and repeats the above steps until the formation is completed according to the preset model.

10. The forming process control method of the space additive manufacturing electron gun according to claim 9, characterized in that: Also includes: The host computer sends a stop signal to the wire feeding mechanism to stop feeding the metal wire. The host computer sends an end command to the DSP control system, and the DSP control system outputs U hvgg The signal is low level, making the high voltage power supply output zero; DSP control system enables U ggas The gas flow controller is turned off, and the DSP control system turns on the pulse power supply discharge switch. pIO The pulse power supply discharge switch is not turned on, and the DSP control system makes the charging voltage signal U pgg is zero, so that the pulse power supply does not work, and the DSP control system makes U dcgg is zero, making the electrostatic field power supply inoperative.

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