CN203164815U - Accelerating power supply for electron beam rapid prototyping manufacturing equipment - Google Patents

Abstract

The utility model discloses an accelerating power supply device for electron beam rapid prototyping manufacturing equipment, which adopts power frequency AC input→power frequency transformer step-up→high-voltage rectification and filtering→high-voltage electron tube series adjustment and adjustment→zinc dioxide piezoresistor or voltage-stabilizing diode. The technical route of parallel voltage regulator output controls the equivalent resistance of the high-voltage tube by outputting high-voltage negative feedback signals and the current signal of the parallel branch of the voltage regulator element, automatically stabilizes the voltage, and limits the current of the parallel branch of the voltage regulator element. The utility model provides a DC high-voltage power supply and its control method, which are composed of high-voltage electronic tubes as series adjustment tubes and zinc dioxide piezoresistors or voltage-stabilizing diodes as parallel-connected voltage-stabilizing elements, and have the advantages of fast adjustment speed and small output high-voltage ripple And the characteristics of high voltage regulation accuracy.

Description

Electron Beam Rapid Prototyping Manufacturing Equipment Accelerates Power Units

technical field

The utility model relates to electron beam rapid prototyping manufacturing equipment, in particular to an accelerating power supply device for electron beam rapid prototyping manufacturing equipment.

Background technique

Electron beam rapid prototyping manufacturing technology uses electron beams to selectively melt metal powder according to the information of the cross-sectional profile of the part under the control of the computer, and accumulates it layer by layer until the entire part is completely melted, and finally removes the excess powder to obtain the product. 3D products required. Compared with laser and plasma beam rapid prototyping, electron beam rapid prototyping has very obvious advantages, such as high energy utilization rate, wide range of processing materials, no reflection, fast processing speed, no pollution in vacuum environment and low operating cost. Electron beam rapid prototyping is an ideal rapid prototyping manufacturing technology for high-performance complex metal parts, and has broad development prospects in aerospace, automotive and biomedical fields. Electron beam rapid prototyping manufacturing equipment is a high-tech product that integrates vacuum physics, precision machinery, electronic technology, electron optics, high voltage technology, computer and control technology, and the accelerating power supply is its key component. Electron beam rapid prototyping manufacturing equipment requires high control precision for the accelerating power supply, small output high voltage ripple coefficient, fast adjustment speed, and small dynamic fluctuation of output voltage.

Utility model content

The technical problem to be solved by the utility model is to provide a high-performance acceleration power supply device for electron beam rapid prototyping manufacturing equipment, which has the advantages of fast adjustment speed, small output high voltage ripple and stable The characteristics of high pressure precision.

In order to solve the above problems, the utility model is achieved through the following technical solutions:

The utility model relates to an accelerating power supply device for electron beam rapid prototyping manufacturing equipment, comprising a power grid filter, a thyristor soft start unit, a high-voltage transformer, a twelve-pulse high-voltage rectification unit, a high-voltage rectification filter capacitor, a high-voltage rectification filter capacitor discharge resistor, and an output high voltage Filter inductor, output high-voltage filter capacitor, output high-voltage filter capacitor discharge current-limiting resistor, voltage stabilizing component parallel branch, accelerating voltage sampling circuit, voltage stabilizing component parallel branch current sampling resistor, electron beam current sampling resistor, high-voltage electron tube, central control unit and the accelerating voltage regulator.

The input end of the grid filter is connected with the external power supply, and the output end is connected with the primary winding of the high voltage transformer through the thyristor soft start unit. The secondary winding of the high-voltage transformer is connected to the input end of the twelve-pulse high-voltage rectification unit, and the high-voltage rectification filter capacitor and the discharge resistor of the high-voltage rectification filter capacitor are connected in parallel to the output end of the twelve-pulse high-voltage rectification unit.

The output high-voltage filter inductor and the output high-voltage filter capacitor form an LC filter circuit. One end of the output high-voltage filter inductor connected to the output high-voltage filter capacitor is connected to the cathode of the electron gun after the output high-voltage filter capacitor discharges the current-limiting resistor, and the other end of the output high-voltage filter inductor is connected to the negative output end of the twelve-pulse high-voltage rectifier unit The other end of the output high-voltage filter capacitor is connected to the ground and the anode of the electron gun after passing through the electron beam current sampling resistor.

The parallel branch of the voltage stabilizing element is composed of a plurality of zinc dioxide varistors or voltage stabilizing diodes connected in series. After the parallel branch of the voltage stabilizing element is connected in series with the current sampling resistor of the parallel branch of the voltage stabilizing element, it is then connected in parallel with the accelerating voltage sampling circuit. Connected to the earth.

The anode of the high-voltage electron tube is connected to the positive output terminal of the twelve-pulse high-voltage rectifier unit, and the cathode of the high-voltage electron tube is connected to the ground through the electron beam current sampling resistor. Both ends of the filament of the high-voltage electron tube are connected to an external constant-current power supply, and the curtain grid of the high-voltage electron tube and its cathode are connected to an external constant-voltage power supply. The grid of the high-voltage electron tube is connected to the output terminal of the accelerating voltage regulator.

The two analog input terminals of the central control unit are respectively connected to the sampling signal output terminal of the acceleration voltage sampling circuit and the sampling signal output terminal of the electron beam current sampling resistor. One output terminal of the central control unit is connected with the thyristor soft start unit.

The five input terminals of the accelerating voltage regulator are respectively connected to the output terminal of the given acceleration voltage signal of the central control unit, the output terminal of the given signal of the electron beam current of the central control unit, the output terminal of the sampling signal of the acceleration voltage sampling circuit, and the parallel connection of the voltage stabilizing element The sampling signal output terminal of the branch current sampling resistor and the sampling signal output terminal of the electron beam current sampling resistor.

As an improvement, the acceleration power supply device of the above-mentioned electron beam rapid prototyping manufacturing equipment further includes a fault discrimination circuit, the input end of the fault discrimination circuit is connected to the sampling signal output end of the electron beam current sampling resistor, the sampling signal of the parallel branch current sampling resistor of the voltage stabilizing element The signal output terminal and the sampling signal output terminal of the acceleration voltage sampling circuit. The output terminal of the fault discrimination circuit is connected with the acceleration voltage regulator and the central control unit.

In the above solution, the accelerating voltage regulator is mainly composed of two transport amplifiers IC1 and IC2, three diodes D1-D3, one voltage regulator diode Z1, eleven resistors R1-R11, and one voltage amplifier. Among them, the electron beam current given signal output terminal of the central control unit is connected to the non-inverting input terminal of the operational amplifier IC2 through the resistor R6, the non-inverting input terminal of the transport amplifier IC2 is connected to the ground through the resistor R7, and the sampling signal output of the electron beam current sampling resistor The terminal is connected to the inverting input terminal of the transport amplifier IC2 through the resistor R5. Both ends of the resistor R8 are respectively connected to the inverting input terminal and the output terminal of the transport amplifier IC2, and the output terminal of the transport amplifier IC2 is connected to the inverting input terminal of the operational amplifier IC1 successively through the Zener diode Z1, the diode D2 and the resistor R4. The acceleration voltage given signal output terminal of the central control unit is connected to the operational amplifier through the resistor R1, the sampling signal output terminal of the acceleration voltage sampling circuit is connected to the operational amplifier through the resistor R2 and the sampling signal output terminal of the parallel branch current sampling resistor of the voltage stabilizing element Inverting input of IC1. The non-inverting input terminal of the operational amplifier IC1 is connected to the ground through R9. The output terminal of the fault discrimination circuit is connected to the non-inverting input terminal of the operational amplifier IC1 through the diode D3. After the diode D2 is connected in parallel with the resistor R10, the cathode of the diode D2 is connected to the inverting input terminal of the operational amplifier IC1, and the anode of the diode D2 is connected to the output terminal of the operational amplifier IC1. The output terminal of the operational amplifier IC1 is connected to the input terminal of the voltage amplifier through the resistor R11, and the output terminal of the voltage amplifier is connected to the gate of the high-voltage tube for accelerating the output of the voltage regulator.

As a further improvement, the sampling signal output end of the above-mentioned electron beam current sampling resistor, the electron beam current given signal output end of the central control unit and the output end of the fault discrimination circuit are also connected with the electron beam current regulator in the electron beam rapid prototyping manufacturing equipment input connection.

In the above solution, the primary winding of the high-voltage transformer is connected in delta or star. One set of secondary windings of the high-voltage transformer is delta connected, the other set of secondary windings is star connected, and the line voltage values of the two sets of secondary windings are the same.

In the above solution, the twelve-pulse high-voltage rectifier unit is composed of two three-phase high-voltage rectifier bridges connected in series, or composed of two three-phase high-voltage rectifier bridges connected in parallel through a balance reactor.

The utility model aims at the high-performance requirements of the electron beam rapid prototyping manufacturing equipment on the accelerating power supply, and provides a DC high-voltage power supply composed of high-voltage electron tubes as series adjustment tubes and zinc dioxide varistors or voltage-stabilizing diodes as parallel-connected voltage-stabilizing elements. and its control method, which have the advantages of fast adjustment speed of the control system, small output high voltage ripple, and high precision of voltage regulation;

Compared with the prior art, the innovation of the utility model is as follows:

1. The structure of the DC high-voltage power supply composed of high-voltage electronic tubes as series adjustment tubes and zinc dioxide varistors or Zener diodes as parallel voltage stabilizing elements;

2. The high-voltage regulator is a proportional regulator structure, and the feedback signal is the acceleration voltage sampling signal and the current sampling signal of the branch of the parallel voltage stabilizing element;

3. The high-voltage regulator plays a role in stabilizing the output voltage when the output voltage of the accelerating power supply does not reach the total voltage regulation value of the branch circuit of the parallel voltage stabilizing element. Finally, it plays the role of limiting the branch current of the shunt voltage stabilizing element;

4. Using the electron beam current sampling signal as the feedback signal, the maximum output current of the accelerating power supply is limited by means of cut-off negative feedback to achieve the over-current protection function.

Description of drawings

Fig. 1 is the schematic diagram of an embodiment of the accelerating power supply device of the electron beam rapid prototyping manufacturing equipment of the present invention;

Fig. 2 is a schematic diagram of a twelve-pulse high-voltage rectifier unit;

FIG. 3 is a schematic diagram of another twelve-pulse high-voltage rectifier unit;

Figure 4 is a schematic diagram of the accelerating voltage regulator;

The labels in the figure are: 1. Grid filter; 2. Thyristor soft start unit; 3. High voltage transformer; 4. Twelve pulse high voltage rectifier unit; 4-1. Balance reactor; 5. High voltage rectifier filter capacitor; 6. High-voltage rectifier filter capacitor discharge resistor; 7. Output high-voltage filter inductor; 8. Output high-voltage filter capacitor; 9. Output high-voltage filter capacitor discharge current-limiting resistor; 10. Parallel branch of voltage stabilizing components; 13. Electronic beam current sampling resistor; 14. High-voltage electron tube; 15. Central control unit; 16. Acceleration voltage regulator; 16-1. Voltage amplifier; 17. Fault discrimination circuit.

Detailed ways

An accelerating power supply device for electron beam rapid prototyping manufacturing equipment, as shown in Figure 1, it is mainly composed of a power grid filter 1, a thyristor soft start unit 2, a high voltage transformer 3, a twelve-pulse high voltage rectification unit 4, and a high voltage rectification filter capacitor 5 , high-voltage rectification filter capacitor discharge resistor 6, output high-voltage filter inductor 7, output high-voltage filter capacitor 8, output high-voltage filter capacitor discharge current-limiting resistor 9, voltage stabilizing element parallel branch 10, accelerating voltage sampling circuit 11, voltage stabilizing element parallel branch Circuit current sampling resistor 12, electron beam current sampling resistor 13, high voltage electron tube 14, central control unit 15, acceleration voltage regulator 16, fault discrimination circuit 17.

The input end of the power grid filter 1 is connected to the external power supply, and the output end is connected to the input end of the thyristor soft start unit 2 . It is used to cut off the propagation path of electromagnetic interference EMI.

The output terminal of the thyristor soft start unit 2 is connected with the primary winding of the high voltage transformer 3 . The thyristor soft-start unit 2 is used as an incoming switch of the high-voltage transformer 3 to suppress the starting current of the high-voltage transformer 3 . When the high-voltage transformer 3 is started, the conduction angle of the thyristor gradually increases to full conduction. In the event of a fault or shutdown, the thyristor is in the off state.

The primary winding of the high-voltage transformer 3 is connected in delta or star; one set of secondary windings of the high-voltage transformer 3 is connected in delta, and the other set of secondary windings is connected in star, and the line voltage values of the two sets of secondary windings same. The primary of the high-voltage transformer 3 is connected to the output of the thyristor soft-start unit 2 , and the secondary is connected to the input of the twelve-pulse high-voltage rectification unit 4 .

The twelve-pulse high-voltage rectifier unit 4 can be composed of two three-phase high-voltage rectifier bridges in series (as shown in Figure 2), or can be composed of two three-phase high-voltage rectifier bridges connected in parallel through a balance reactor 4-1 (as shown in Figure 3 shown).

The high-voltage rectification filter capacitor 5 and the high-voltage rectification filter capacitor discharge resistor 6 are connected in parallel to the output end of the twelve-pulse high-voltage rectification unit 4 . Wherein, the function of the discharge resistor 6 of the high-voltage rectification filter capacitor is to provide a discharge circuit for the high-voltage rectifier filter capacitor 5 after shutdown.

The output high voltage filter inductor 7 and the output high voltage filter capacitor 8 form an LC filter circuit. One end of the output high-voltage filter inductor 7 connected to the output high-voltage filter capacitor 8 is connected to the cathode of the electron gun after the output high-voltage filter capacitor discharges the current-limiting resistor 9, and the other end of the output high-voltage filter inductor 7 is connected to the twelve-pulse high-voltage rectifier unit On the negative output end of 4, the other end of the output high voltage filter capacitor 8 is then connected to the earth and the anode of the electron gun after passing through the electron beam current sampling resistor 13.

The voltage stabilizing element parallel branch 10 is composed of a plurality of zinc dioxide varistors or voltage stabilizing silicon stacks (i.e. Zener diodes) in series, and the highest output voltage of the acceleration power supply is regulated in series by the voltage stabilizing element parallel connecting branch 10 Value decides.

The current sampling resistor 12 of the parallel branch of the voltage stabilizing element is connected in series with the parallel branch of the voltage stabilizing element 10 . It is used to measure the current value flowing through the parallel branch 10 of the voltage stabilizing element, and output a voltage signal U _y proportional to the current value.

The parallel branch of the voltage stabilizing element 10 is connected in series with the current sampling resistor 12 of the parallel branch of the voltage stabilizing element, and connected to the output end of the accelerating power supply, that is, the high voltage end and the output end of the output high voltage filter capacitor discharge current limiting resistor 9, which is the cathode of the electron gun Connected, the low-voltage side is connected to the earth.

The accelerating voltage sampling circuit 11 is connected in parallel with the output end of the accelerating power supply, that is, the high voltage end is connected with the output end of the output high voltage filter capacitor discharge current limiting resistor 9, that is, the cathode of the electron gun, and the low voltage end is connected with the ground. It is used to measure the acceleration voltage value and output a voltage signal U _a proportional to the acceleration voltage.

The electron beam current sampling resistor 13 is used to detect the electron beam current value, and the two ends of this resistor output a voltage signal U _e proportional to the magnitude of the electron beam current (including the parallel branch of the voltage stabilizing element and the current of the accelerating voltage sampling circuit).

The anode of the high-voltage electron tube 14 is connected to the positive output terminal of the twelve-pulse high-voltage rectification unit 4, the cathode of the high-voltage electron tube 14 is connected to the earth through the electron beam current sampling resistor 13; the two ends of the filament of the high-voltage electron tube 14 are connected to an external constant current power supply , the curtain grid and the cathode of the high-voltage electron tube 14 are connected to an external constant voltage power supply. The grid of the high-voltage electron tube 14 is connected to the output terminal of the accelerating voltage regulator 16 . The working state of the high-voltage electron tube 14 is controlled by the grid voltage _Uc .

The central control unit has two analog input terminals, which are respectively connected to the sampling signal output terminal 11 of the acceleration voltage sampling circuit and the sampling signal output terminal of the electron beam current sampling resistor 13 . One output end of the central control unit 15 is connected with the thyristor soft start unit 2 . The central control unit 15 is composed of an industrial computer or a programmable logic controller PLC. The functions of the central control unit 15 in the acceleration power supply system are: 1. Control the soft start of the high-voltage transformer 3; The given voltage signal U _a ^* is sent to the accelerating voltage regulator 16, which is used to generate the setting waveform of the accelerating voltage, including the setting of the rising and falling slope and the working voltage; The fixed signal U _e ^* is sent to the accelerating voltage regulator 16 and the electron beam current regulator, which is used to generate the setting waveform of the electron beam current, including the setting of the rising and falling slope and the working electron beam current; 4. Receive the accelerating voltage sampling circuit 11 The acceleration voltage sampling signal U _a sent is used for indication, etc.; 5. Receive the electron beam current sampling signal U _e sent by the electron beam current sampling resistor 13 for indication, etc.; 6. Receive the output signal of the fault discrimination circuit 17 U _er is used for multiple fault protection, chain protection of other parts of the equipment and fault prompt.

The five input terminals of the acceleration voltage regulator 16 respectively receive the acceleration voltage given signal U _a ^* of the central control unit 15, the electron beam current given signal U _e ^* of the central control unit 15, and the sampling signal U of the acceleration voltage sampling circuit 11. _a . The sampling signal U _y of the current sampling resistor 12 in the parallel branch of the voltage stabilizing element and the sampling signal U _e of the electron beam current sampling resistor 13 . During normal operation, when the accelerating voltage is lower than the stabilizing value of the voltage stabilizing element, the given signal U _a ^* of the accelerating voltage is compared with the sampling signal U _a of the accelerating voltage, and the deviation is amplified to control the grid of the high-voltage electron tube 14; when When the accelerating voltage reaches the voltage stabilizing value of the voltage stabilizing element, the acceleration voltage given signal U _a ^* is compared with the sampling signal U _{a of the accelerating voltage, and then compared with the current sampling signal U y of} the parallel branch of the voltage stabilizing element, and the total deviation is passed Amplified to control the grid of the high-voltage electron tube 14. In addition, when the fault discrimination circuit 17 has an output, the output of the acceleration voltage regulator 16 will be blocked, so that the high-voltage electronic tube 14 is cut off.

In the present utility model, the acceleration voltage regulator 16 is as shown in Figure 4, which is mainly composed of 2 transport amplifiers IC1, IC2, 3 diodes D1～D3, voltage regulator diode Z1, 11 resistors R1～R11, and The voltage amplifier 16-1 is composed. Wherein the electron beam current given signal _Ue ^* of the central control unit 15 is connected to the non-inverting input terminal of the operational amplifier IC2 through the resistor R6, the non-inverting input terminal of the transport amplifier IC2 is connected to the earth through the resistor R7, and the electron beam current sampling resistor 13 The sampling signal _Ue is connected to the inverting input terminal of the transport amplifier IC2 through the resistor R5. Both ends of the resistor R8 are respectively connected to the inverting input terminal and the output terminal of the transport amplifier IC2, and the output terminal of the transport amplifier IC2 is connected to the inverting input terminal of the operational amplifier IC1 successively through the Zener diode Z1, the diode D2 and the resistor R4. The acceleration voltage given signal U _a ^* of the central control unit 15 passes through the resistor R1, the sampling signal U _a of the acceleration voltage sampling circuit 11 passes through the resistor R2, and the sampling signal U _y of the parallel branch current sampling resistor 12 of the voltage stabilizing element passes through the resistor R3 Connect together to the inverting input of operational amplifier IC1. The output signal U _er of the fault discrimination circuit 17 is connected to the non-inverting input terminal of the operational amplifier IC1 through the diode D3. The non-inverting input terminal of the operational amplifier IC1 is connected to the ground through R9. After the diode D2 is connected in parallel with the resistor R10, the cathode of the diode D2 is connected to the inverting input terminal of the operational amplifier IC1, and the anode of the diode D2 is connected to the output terminal of the operational amplifier IC1. The output signal _U1 of the operational amplifier IC1 is connected to the input terminal of the voltage amplifier 16-1 through the resistor R11, and the output voltage _Uc of the voltage amplifier 16-1 is sent to the gate of the high-voltage electron tube 14.

The input terminal of fault discrimination circuit 17 receives the sampling signal U _e of electron beam current sampling resistance 13, the sampling signal U _y of voltage stabilizing element parallel branch current sampling resistance 12 and the sampling signal U _a of acceleration voltage sampling circuit 11; fault discrimination circuit The output signal U _er of 17 is sent to the accelerating voltage regulator 16, the central control unit 15 and the electron beam regulator. The fault discrimination circuit 17 detects the voltage signal U _e on the electron beam current sampling resistor 13, and if it exceeds the set upper limit, it is judged as the electron beam current overcurrent fault; the fault discrimination circuit 17 detects the parallel branch current sampling resistor 12 of the voltage stabilizing element On the voltage signal U _y , if it exceeds the set upper limit, it is judged as an overcurrent fault of the voltage stabilizing element; the fault discrimination circuit 17 detects the output voltage signal U _a of the accelerated high-voltage sampling circuit 11, and if it exceeds the set upper limit, it is judged For the acceleration voltage overvoltage fault, if a negative sudden change occurs, it is judged that the acceleration power supply produces a high-voltage discharge fault; the output signal U _er of the fault discrimination circuit 17 of any of the above faults becomes a high level, and immediately blocks the acceleration voltage regulator 16 and the output of the electron beam current regulator; if a high-voltage discharge fault occurs, after the output U _a ^* and U _e ^* signals of the acceleration voltage regulator 16, the electron beam current regulator and the central control unit 15 are blocked for 1-3 milliseconds, Automatically release the blockade and realize high-voltage automatic restart; if the number of high-voltage discharge faults exceeds the set number within a set period of time, it will be judged as a "permanent fault". At this time, cut off the grid power supply and accelerate the voltage to the Set the signal, and restart the high voltage manually after the fault is eliminated.

In addition, the sampling signal U _e of the electron beam current sampling resistor 13, the electron beam current given signal U _e ^* of the central control unit 15, and the output signal U _er of the fault discrimination circuit 17 are also respectively sent to the electron beam rapid prototyping manufacturing equipment. Input to the beam modulator.

Based on the acceleration power supply device mentioned above, a control method for the acceleration power supply device of the electron beam rapid prototyping manufacturing equipment adopts power frequency AC input → power frequency transformer step-up → high voltage rectification and filtering → high voltage electron tube 14 series adjustment adjustment → zinc dioxide pressure Sensitive resistors or voltage stabilizing diodes are the technical route of parallel voltage stabilizing output, and the equivalent resistance of high voltage electronic tube 14 is controlled by outputting high-voltage negative feedback signal U _a and the current signal U _y of the parallel branch circuit 10 of the voltage stabilizing element to perform automatic stabilizing voltage, and limit the current of the parallel branch 10 of the voltage stabilizing element.

The power frequency AC input is under the control of the central control unit 15, and the conduction angle of the thyristor in the thyristor soft start unit 2 gradually increases from 0 to full conduction, and enters normal operation.

If the acceleration voltage given value Ua* is low, and the output voltage value of the acceleration power supply is lower than the total stable voltage value of the parallel branch 10 of the voltage stabilizing element, no current flows through the parallel branch 10 of the voltage stabilizing element, and the parallel connection of the stabilizing element If the current sampling signal U _y of the branch 10 is zero, then only the acceleration voltage given signal U _a ^* is compared with the acceleration voltage sampling signal U _a , and the deviation is amplified to control the grid of the high-voltage electron tube 14 to accelerate the output voltage value of the power supply It is proportional to the given value of the acceleration voltage; if the given value of the acceleration voltage U _a ^* exceeds a certain critical value, and the acceleration voltage reaches the voltage stabilizing value of the voltage stabilizing element, at this time there is current passing through the parallel branch of the voltage stabilizing element, Then, the acceleration voltage given signal U _a ^* is compared with the acceleration voltage sampling signal U _{a, and then compared with the current sampling signal U y of} the parallel branch 10 of the voltage stabilizing element, and the total deviation is amplified to control the grid of the high-voltage electron tube 14 , the output voltage value of the acceleration power supply is stabilized at the total regulated value of the parallel branch 10 of the voltage stabilizing element, and the current value of the parallel branch 10 of the voltage stabilizing element is proportional to the acceleration voltage given value U _a ^* and the critical value U _aN ^* difference; if the acceleration voltage given value U _a ^* is equal to the critical value U _aN ^* , the output voltage value of the acceleration power supply is equal to the total stable voltage value of the parallel branch 10 of the voltage stabilizing element, but there is still no current passing through the parallel branch of the voltage stabilizing element . The above-mentioned high pressure regulator adopts proportional adjustment, has simple structure and fast adjustment speed. Abnormal operation: 1. The electron beam current exceeds its given value, and the deviation exceeds the set upper limit value, the negative feedback effect is cut off through the electron beam current sampling signal, and the output of the high voltage regulator 16 is reduced, thereby limiting the electron beam current; 2. When the fault discrimination circuit 17 has an output, the output of the acceleration voltage regulator 16 will be blocked, so that the high-voltage electronic tube 14 is cut off.

The structure of the high-voltage regulator 16 is shown in Figure 4. The electron beam current given signal U _e ^* is sent to the non-inverting input terminal of the operational amplifier IC2 through the resistor R6, and the non-inverting input terminal of the operational amplifier IC2 is connected to the ground through the resistor R7. The current sampling signal U _e is sent to the inverting input terminal of the operational amplifier IC2 through the resistor R5, and the two ends of the resistor R8 are respectively connected to the inverting input terminal and the output terminal of the operational amplifier IC2, and the output signal _U2 of the operational amplifier IC2 passes through the voltage regulator successively. Diode Z1, diode D2 and resistor R4 are sent to the inverting input of operational amplifier IC1. The output of the operational amplifier IC2 For the convenience of analysis, let R7=R8, R5=R6, then When working normally, the electron beam current will not exceed the set value under the action of the electron beam current regulator, that is, U _e ≤ _{U e} ^* , so U ₂ is positive, and diode D2 is under the back pressure to block U ₂ from being sent to the operation The inverting input terminal of the amplifier IC1; if the electron beam current exceeds the set value due to abnormal reasons, that is, U _e > U _e ^* , _{U 2} becomes negative. The voltage drop V _Z1 , that is, the (U ₂ -V _Z1 ) signal is sent to the inverting input of the operational amplifier IC1 through the resistor R4.

式中U_a ^*、U_a和U_y以绝对值计算，为了便于分析令R1=R2=R3，则

如果加速电压给定值U_a ^*较低，而加速电源输出电压值低于稳压元件的总稳压值时，稳压元件并联支路10无电流通过，即U_y=0，那么

U₁为可变负电压，高压调节器3中只有加速电压给定信号U_a ^*和加速电压取样信号U_a进行比较，偏差通过放大后去控制高压电子管14的栅极，加速电源的输出电压值与加速电压给定值U_a ^*成比例关系。如果加速电压给定值U_a ^*超过某一个临界值U_aN ^*，而加速电压达到稳压元件的总稳压值，此时稳压元件并联支路10中有电流通过，即U_y≠0，那么U₁为可变负电压，加速电压给定信号U_a ^*和加速电压取样信号U_a进行比较后，再与稳压元件并联支路电流取样信号U_y进行比较，总偏差通过放大后去控制高压电子管14的栅极，加速电源的输出电压值稳定在稳压元件并联支路的总稳压值，加速电压取样信号U_a为固定值U_aN，稳压元件并联支路10的电流值正比于加速电压给定值U_a ^*与临界值U_aN ^*的差值。如果加速电压给定值U_a ^*等于临界值U_aN ^*，加速电源的输出电压值等于稳压元件并联支路的总稳压值，但稳压元件并联支路10仍无电流通过，

U₁为可变负电压；如果U₂为负且已达Z1的稳压值，此时 $U_1=-\frac{R11}{R1}(U_a^{*}-U_a-U_y)+\frac{R11}{R4}(U_2-V_{Z1})$ 或 $U_1=-\frac{R11}{R1}(U_a^{*}-U_a)+\frac{R11}{R4}(U_2-V_{Z1}),$ 式中U_a ^*、U_a、U_y、U₂和V_Z1用绝对值计算，U₁为可变负电压，由于电阻R4远小于电阻R1、R2和R3，信号（U₂-V_Z1）形成截止负反馈，使得U₂负最大值被限制在V_Z1附近；一旦故障信号有效，U_er为正电平，U_er即通过D3送至IC1的同相输入端，在D2的作用下，IC1变成电压跟随器而输出正电平，U₁为正时，电压放大器16-1输出负最大电压信号，高压电子管14被截止。Acceleration voltage given signal U _a ^* passes through resistor R1, acceleration voltage sampling signal U _a passes through resistor R2, and current sampling signal U _y of the parallel branch of the voltage stabilizing element is sent to the inverting input terminal of operational amplifier IC1 through resistor R3. The non-inverting input terminal of the operational amplifier IC1 is connected to the ground through the resistor R9, and the fault signal U _er is sent to the non-inverting input terminal of the operational amplifier IC1 through the diode D3. After the diode D2 and the resistor R10 are connected in parallel, the cathode of the diode D2 is connected to the inverting input terminal of the operational amplifier IC1, the anode of the diode D2 is connected to the output terminal of the operational amplifier IC1, and the output signal _U1 of the operational amplifier IC1 is sent to the voltage amplifier 16 through the resistor R11 -1 control terminal, the output signal _Uc of the voltage amplifier 16-1 is sent to the gate of the high-voltage electron tube 14. When the fault signal is invalid, U _er is at low level, the blocking effect of diode D3 U _er has no effect on the acceleration voltage regulator, and the Zener diode Z1 and/or diode D1 are in the blocking state, the output signal of the operational amplifier IC1

In the formula, U _a ^* , U _a and U _y are calculated by absolute value, for the convenience of analysis, let R1=R2=R3, then

If the acceleration voltage given value U _a ^* is low, and the output voltage value of the acceleration power supply is lower than the total regulated value of the voltage stabilizing element, the parallel branch 10 of the stabilizing element has no current passing through, that is, U _y =0, then

U ₁ is a variable negative voltage. In the high-voltage regulator 3, only the acceleration voltage given signal U _a ^* is compared with the acceleration voltage sampling signal U _a , and the deviation is amplified to control the grid of the high-voltage electron tube 14 to accelerate the output voltage of the power supply. The value is proportional to the acceleration voltage given value U _a ^* . If the acceleration voltage given value U _a ^* exceeds a certain critical value U _aN ^* , and the acceleration voltage reaches the total stable voltage value of the voltage stabilizing element, at this time there is current in the parallel branch 10 of the voltage stabilizing element, that is, U _y ≠0 ,So U ₁ is a variable negative voltage. After comparing the acceleration voltage given signal U _a ^* with the acceleration voltage sampling signal U _a , it is compared with the current sampling signal U _y of the parallel branch of the voltage stabilizing element, and the total deviation is controlled after being amplified. The grid of the high-voltage electron tube 14, the output voltage value of the acceleration power supply is stable at the total voltage stabilization value of the parallel branch of the voltage stabilizing element, the acceleration voltage sampling signal U _a is a fixed value U _aN , and the current value of the parallel connection branch 10 of the voltage stabilizing element is proportional to It is based on the difference between the acceleration voltage given value U _a ^* and the critical value U _aN ^* . If the acceleration voltage given value U _a ^* is equal to the critical value U _aN ^* , the output voltage value of the acceleration power supply is equal to the total stable voltage value of the parallel branch of the voltage stabilizing element, but the parallel branch 10 of the stabilizing element still has no current passing through,

U ₁ is a variable negative voltage; if U ₂ is negative and has reached the regulated value of Z1, then $u_1=-\frac{R11}{R1}(u_a^{*}-u_a-u_{\mathrm{the\; y}})+\frac{R11}{R4}(u_2-V_{Z1})$ or $u_1=-\frac{R11}{R1}(u_a^{*}-u_a)+\frac{R11}{R4}(u_2-V_{Z1}),$ In the formula, U _a ^* , U _a , U _y , U ₂ and V _Z1 are calculated by absolute value, and U ₁ is a variable negative voltage. Since the resistance R4 is much smaller than the resistance R1, R2 and R3, the signal (U ₂ -V _Z1 ) A cut-off negative feedback is formed, so that the negative maximum value of U ₂ is limited near V _Z1 ; once the fault signal is valid, U _er is at a positive level, and U _er is sent to the non-inverting input terminal of IC1 through D3. Under the action of D2, IC1 Become a voltage follower and output positive level, when _U1 is positive, the voltage amplifier 16-1 outputs a negative maximum voltage signal, and the high-voltage electron tube 14 is cut off.

As an improvement, the control method for accelerating the power supply device of the above-mentioned electron beam rapid prototyping manufacturing equipment further includes fault protection control, that is, the fault discrimination circuit 17 detects the voltage signal U _e on the electron beam current sampling resistor 13, if it exceeds the set upper limit The value is judged as the electron beam current overcurrent fault. The fault discrimination circuit 17 detects the voltage signal U _y on the current sampling resistor 12 of the parallel branch of the voltage stabilizing element, and if it exceeds the set upper limit, it is determined that the parallel branch of the voltage stabilizing element 10 has an overcurrent fault. The fault discrimination circuit 17 detects the output voltage signal of the accelerating high-voltage sampling circuit 11. If it exceeds the set upper limit, it is judged as an overvoltage fault of the accelerating voltage. If a negative sudden change occurs, it is judged as a high-voltage discharge fault of the accelerating power supply. When any of the above faults occurs, the output signal U _er of the fault discrimination circuit becomes high level, and immediately blocks the output of the accelerating voltage regulator 16 and the electron beam current regulator. The output signal of the fault discrimination circuit 17 is simultaneously sent to the central control unit 15 for fault display and chain protection of other control units of the electron beam rapid prototyping manufacturing equipment. If a high-voltage discharge fault occurs, the output of the acceleration voltage regulator 16 and the electron beam current regulator, and the output signals U _a ^* and U _e ^* of the central control unit 15 are simultaneously blocked for 1-2 milliseconds, and then the block is automatically released to realize high-voltage automatic discharge. reboot. If the number of high-voltage discharge faults within the set period of time exceeds the set number, it will be judged as a "permanent fault". At this time, the same as the measures to deal with other fault types, cut off the grid power supply and the given signal, and restart it manually after the fault is eliminated. high pressure.

Claims (6)

1. electron beam rapid shaping manufacturing equipment accelerating power source device is characterized in that: comprise line filter (1), thyristor soft start unit (2), high-tension transformer (3), 12 pulsating wave high-voltage rectifying unit (4), high-voltage rectifying filter capacitor (5), high-voltage rectifying filter capacitor discharge resistance (6), output hv filtering inductance (7), output high-voltage filtering capacitor (8), output high-voltage filtering capacitor discharge current-limiting resistance (9), voltage stabilizing element parallel branch (10), accelerating potential sample circuit (11), voltage stabilizing element parallel branch current sampling resistor (12), electronic beam current sample resistance (13), high-voltage electrical tube (14), central control unit (15) and accelerating potential regulator (16);

The input end of line filter (1) links to each other with external power source, and the elementary winding with high-tension transformer (3) links to each other output terminal through thyristor soft start unit (2); High-tension transformer (3) secondary winding connects the input end of 12 pulsating wave high-voltage rectifying unit (4), is connected on the output terminal of 12 pulsating wave high-voltage rectifying unit (4) after high-voltage rectifying filter capacitor (5) and high-voltage rectifying filter capacitor discharge resistance (6) parallel connection;

Output hv filtering inductance (7) and output high-voltage filtering capacitor (8) are formed the LC filtering circuit; Wherein export hv filtering inductance (7) and the end that links to each other of output high-voltage filtering capacitor (8) by output high-voltage filtering capacitor discharge current-limiting resistance (9) after and the negative electrode of electron gun join, the other end of output hv filtering inductance (7) is connected on the negative output terminal of 12 pulsating wave high-voltage rectifying unit (4), and the anode that the other end of output high-voltage filtering capacitor (8) then passes through electronic beam current sample resistance (13) back and the earth and electron gun joins;

Voltage stabilizing element parallel branch (10) is composed in series by a plurality of zinc oxide voltage dependent resistor (VDR)s or voltage stabilizing diode, voltage stabilizing element parallel branch (10) is with after voltage stabilizing element parallel branch current sampling resistor (12) is connected, in parallel with accelerating potential sample circuit (11) again, one of two parallel branches terminate at the output terminal of output high-voltage filtering capacitor discharge current-limiting resistance (9), and the other end links to each other with the earth;

The positive output end of the anode of high-voltage electrical tube (14) and 12 pulsating wave high-voltage rectifying unit (4) joins, and the negative electrode of high-voltage electrical tube (14) joins by electronic beam current sample resistance (13) and the earth; The outside constant-current supply of filament two terminations of high-voltage electrical tube (14), the indirect outside constant voltage source of the screen grid of high-voltage electrical tube (14) and its negative electrode; The grid of high-voltage electrical tube (14) connects on the output terminal of accelerating potential regulator (16);

Central control unit has 2 road analog input ends to connect the sampled signal output terminal of accelerating potential sample circuit (11) and the sampled signal output terminal (13) of electronic beam current sample resistance respectively; An output terminal of central control unit (15) connects thyristor soft start unit (2);

5 road input ends of accelerating potential regulator (16) connect the given signal output part of accelerating potential of central control unit (15), the given signal output part of electronic beam current of central control unit (15), the sampled signal output terminal of accelerating potential sample circuit (11), the sampled signal output terminal of voltage stabilizing element parallel branch current sampling resistor (12) and the sampled signal output terminal of electronic beam current sample resistance (13) respectively.

2. electron beam rapid shaping manufacturing equipment accelerating power source device according to claim 1, it is characterized in that: also further comprise fault distinguishing circuit (17), the input end of this fault distinguishing circuit (17) connects sampled signal output terminal, the sampled signal output terminal of voltage stabilizing element parallel branch current sampling resistor (12) and the sampled signal output terminal of accelerating potential sample circuit (11) of electronic beam current sample resistance (13); The output terminal of fault distinguishing circuit (17) connects accelerating potential regulator (16) and central control unit (15).

3. electron beam rapid shaping manufacturing equipment accelerating power source device according to claim 2, it is characterized in that: described accelerating potential regulator (16) is mainly by 2 transportation amplifier IC1, IC2,3 diode D1～D3, voltage stabilizing diode Z1,11 resistance R 1～R11, and voltage amplifier (16-1) is formed; Wherein

The given signal output part of electronic beam current of central control unit (15) is connected to the in-phase input end of operational amplifier IC2 by resistance R 6, the in-phase input end of transportation amplifier IC2 joins by resistance R 7 and the earth, and the sampled signal output terminal of electronic beam current sample resistance (13) connects the inverting input of transportation amplifier IC2 by resistance R 5; Resistance R 8 two ends are connected to inverting input and the output terminal of transportation amplifier IC2 respectively, and the output terminal of transportation amplifier IC2 successively is connected to the inverting input of operational amplifier IC1 by voltage stabilizing diode Z1, diode D2 and resistance R 4;

The given signal output part of accelerating potential of central control unit (15) is connected to the inverting input of operational amplifier IC1 together by resistance R 3 by the sampled signal output terminal of resistance R 2 and voltage stabilizing element parallel branch current sampling resistor (12) by the sampled signal output terminal of resistance R 1, accelerating potential sample circuit (11); The in-phase input end of operational amplifier IC1 joins by R9 and the earth; The output terminal of fault distinguishing circuit (17) is connected to the in-phase input end of operational amplifier IC1 through diode D3; After diode D2 and resistance R 10 were in parallel, the negative electrode of diode D2 connect the inverting input of operational amplifier IC1, and the anode of diode D2 connects the output terminal of operational amplifier IC1; The output terminal of operational amplifier IC1 is connected to the input end of voltage amplifier (16-1) by resistance R 11, and the output terminal of voltage amplifier (16-1) is the grid that the output terminal of accelerating potential regulator (16) is connected to high-voltage electrical tube.

4. according to the described electron beam rapid shaping of claim 2 manufacturing equipment accelerating power source device, it is characterized in that: the given signal output part of electronic beam current of the sampled signal output terminal of electronic beam current sample resistance (13), central control unit (15) and the output terminal of fault distinguishing circuit (17) also are connected with the input end of electronic beam current regulator (19) in the electron beam rapid shaping manufacturing equipment.

5. electron beam rapid shaping manufacturing equipment accelerating power source device according to claim 1, it is characterized in that: the elementary winding of described high-tension transformer (3) is triangle or star connection; One group of secondary winding of high-tension transformer (3) is delta connection, and another group secondary winding is star connection, and the line magnitude of voltage of two groups of secondary winding is identical.

6. electron beam rapid shaping manufacturing equipment accelerating power source device according to claim 1, it is characterized in that: described 12 pulsating wave high-voltage rectifying unit (4) is composed in series by two three-phase high-voltage rectifier bridges, or is composed in parallel by paralleing reactor (4-1) by two three-phase high-voltage rectifier bridges.

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