Method for preventing over-voltage impact of collector during power-on and power-off and electric vacuum tube transmitter

Abstract

A method for preventing overvoltage impact of a collector in the power-on and power-off process of an electric vacuum tube transmitter comprises the steps that S01, it is guaranteed that a collector power source Uc and a cathode power source Uk of the electric vacuum tube transmitter are powered on and powered off synchronously, shutdown is conducted in a fault chain mode, and the situation that only one power source works is prevented; s02, the collector power supply voltage Vc and the cathode power supply voltage Vk of the electric vacuum tube transmitter are guaranteed to be synchronously adjusted and decreased in the power-off process, through the step S01, when power is off, two power supplies do not output at the same time, energy storage capacitors of a collector C and a cathode K automatically discharge at the same time, a resistance-capacitance circuit is designed, the automatic discharge time rate of the energy storage capacitors of the collector C and the cathode K is controlled, and the self-discharge time rate of the energy storage capacitors of the collector C and the cathode K is controlled. The collector C is ensured not to be over-voltage to the ground in the discharging process; and S03, during high-voltage power-on, charging the energy storage capacitor by the collector power supply Uc and the cathode power supply Uk, determining a collector working delay circuit according to the charging speed of the two power supplies to the energy storage capacitor, and ensuring that the voltage to ground of the collector C in the power-on process is within a safe range. According to the invention, power-on and power-off impact of the electric vacuum tube can be avoided, and the vacuum tube can be timely and effectively protected when a power grid is powered off, a transmitter is ignited and an accidental power failure occurs.

Description

Technical Field

[0001] The present invention relates to the field of transmitters, especially to the technical field of the core device of transmitters, i.e., the electro-vacuum tube technology. Background Art

[0002] In large-scale scientific projects, the demand for high-power transmitters has been continuously increasing. High-power electro-vacuum tubes are the core devices of common high-power transmitters. Their stability and service life have always been the weaknesses of high-power transmitters. A reliable high-voltage power supply system is the key to preventing the electro-vacuum tube from arcing and ensuring its service life. When the transmitter powers on, powers off, or experiences a power failure under special circumstances (such as arcing or grid power failure), if the instantaneous voltage amplitude and current intensity cannot be effectively limited, resulting in voltage and current surges, multiple small surges will also affect the service life of the vacuum tube. Large surges will often cause direct damage to the electro-vacuum tube or the modulation circuit of the transmitter. In the worst case, it will cause high-voltage arcing, which not only damages the electro-vacuum tube transmitter but also may cause a large load traction on the power grid or power station, resulting in instantaneous interference to the power station and power grid and causing a power trip. Therefore, a reliable power protection system and a timely and orderly high-voltage power-on, power-off, and power-failure protection process are crucial for the long-term reliable operation of high-power electro-vacuum tube transmitters.

[0003] First, introduce the circuit principle of the electro-vacuum tube transmitter, as Figure 1 shown, the high-power electro-vacuum tube transmitter includes a collector C, a cathode K, a grid G, a filament F, and a tube body B. The tube body B is grounded. The power supply system of the high-power electro-vacuum tube transmitter includes a cathode power supply Uk, a collector power supply Uc, a filament power supply Uf, and a grid pulse modulation.

[0004] Among them, the filament power supply Uf and the grid pulse modulation are low-voltage and low-power power supplies, floating above the high voltage of the cathode power supply Uk, with little potential difference from the cathode K. Both the cathode power supply Uk and the collector power supply Uc are high-voltage and high-power power supplies, and are both negatively high voltages with respect to the ground during operation. For high-power electro-vacuum tube transmitters, when the requirements are not high, the cathode power supply Uk and the collector power supply Uc are often designed uniformly, and the cathode power supply Uk with higher precision requirements is closed-loop. However, this will cause the collector voltage Uc to have large voltage fluctuations and poor stability. For high-power transmitters with high cathode voltage and higher system stability requirements, the collector power supply Uc and the cathode power supply Uk cannot be designed with a single closed-loop linkage. They need to be sampled and closed-loop designed separately to ensure the stability of the collector voltage.

[0005] When the collector power supply Uc and the cathode power supply Uk are designed independently, the cathode power supply Uk forms a current loop between the cathode K and the tube body ground. The cathode power supply Uk outputs negative high voltage, and the cathode power supply voltage Vk is higher than the collector power supply voltage Vc. The collector power supply Uc forms a loop between the collector C and the cathode K and is a positive high voltage power supply floating on the cathode power supply voltage Vk. When the transmitter is working normally, the potential of the collector C with respect to the ground is the difference between the cathode power supply voltage Vk and the collector power supply voltage Vc, i.e., Vc(Vk - Vc), which is usually lower than the cathode power supply voltage Vk and the collector power supply voltage Vc. In the production design of the electron tube, the withstand voltage of the collector C with respect to the ground is not only much lower than the cathode power supply voltage Vk but also usually lower than the collector power supply voltage Vc. Therefore, when the difference between the cathode power supply voltage Vk and the collector power supply voltage Vc, Vk - Vc, is greater than the withstand voltage of the collector with respect to the ground, it will cause a high voltage impact on the collector C and even cause the collector C to spark due to insufficient withstand voltage, damaging the electron tube. This situation often occurs at the moment of high voltage power-on, power-off of the transmitter, as well as when the cathode power supply Uk fails and the collector power supply Uc fails. To prevent this from happening, it is necessary to optimize the synchronous operation, startup boost process, power-down step-down process, and fault interlock of the collector power supply Uc and the cathode power supply Uk. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to limit the instantaneous voltage amplitude and current intensity of the electron tube transmitter to avoid voltage and current shocks.

[0007] The present invention solves the above technical problems through the following technical means: A method for preventing overvoltage shock of the collector during the power-on and power-off processes of an electron tube transmitter, including the following three steps:

[0008] S01. Ensure that the collector power supply Uc and the cathode power supply Uk of the electron tube transmitter are synchronized during startup and shutdown, and shut down in case of a fault interlock to prevent the situation where only one power supply works.

[0009] S02. Ensure that the collector power supply voltage Vc and the cathode power supply voltage Vk of the electron tube transmitter decrease synchronously during the power-off process. After step S01, when powering off, both power supplies will have no output at the same time, and the energy storage capacitors of the collector C and the cathode K will discharge independently. Design a resistor-capacitor circuit to control the independent discharge time rate of the energy storage capacitors of the collector C and the cathode K to ensure that the voltage of the collector C with respect to the ground does not exceed the voltage during the discharge process.

[0010] S03. When powering on with high voltage, the collector power supply Uc and the cathode power supply Uk charge the energy storage capacitor. Determine the collector working delay circuit according to the charging speed of the two power supplies to the energy storage capacitor to ensure that the voltage of the collector C with respect to the ground is within a safe range during the power-on process.

[0011] As a further optimized technical solution, in the step S01, it is necessary to synchronously control the power-on enable signals of the collector power supply Uc and the cathode power supply Uk.

[0012] As a further optimized technical solution, a synchronous control circuit for the power-on enable signals of the collector power supply and the cathode power supply is designed, including optocouplers V1, V2, V3, V4, resistors R1, R2, R3, capacitors C1, C2;

[0013] Among them, the port 1 of the optocoupler V1 is connected to the resistor R1, the other end of the resistor R1 is used as the power-on enable signal input terminal, the port 2 of the optocoupler V1 is connected to the port 1 of the optocoupler V2, the port 3 of the optocoupler V1 is used as the cathode power supply enable signal output terminal, and the port 4 of the optocoupler V1 is used as the +15V power supply input terminal; the port 2 of the optocoupler V2 is connected to the port 4 of the optocoupler V3, the port 3 of the optocoupler V2 is used as the collector power supply enable signal output terminal, and the port 4 of the optocoupler V2 is used as the +15V power supply input terminal; the port 1 of the optocoupler V3 is connected to the resistor R2, the other end of the resistor R2 is used as the cathode power supply fault input terminal, the port 2 of the optocoupler V3 is grounded, a capacitor C1 is connected between the port 1 and 2 of the optocoupler V3, and the port 3 of the optocoupler V3 is connected to the port 4 of the optocoupler V4; the port 1 of the optocoupler V4 is connected to the resistor R3, the other end of the resistor R3 is used as the collector power supply fault input terminal, the port 2 of the optocoupler V4 is grounded, a capacitor C2 is connected between the port 1 and 2 of the optocoupler V4, and the port 3 of the optocoupler V4 is grounded.

[0014] As a further optimized technical solution, in this embodiment, the models of the optocouplers V1, V2, V3, and V4 are TLP281-1.

[0015] As a further optimized technical solution, all levels are normal with high levels, and the cathode power supply enable signal and the collector power supply enable signal can be disconnected when the circuit or other devices are disconnected.

[0016] As a further optimized technical solution, in the step S02, the designed resistor-capacitor circuit includes resistors R11, R12, impedance R13, capacitors C11, C12, C13. The resistor R11 and the capacitor C11 are connected in parallel between the cathode K and the tube body ground, the resistor R12 and the capacitor C12 are connected in parallel between the cathode K and the collector C, and an impedance R13 and a ground capacitor C13 are formed between the collector C and the tube body ground;

[0017] The resistor R11 and the capacitor C11 are the energy storage capacitor and the sampling resistor for the cathode power supply Uk, and the resistor R12 and the capacitor C12 are the energy storage capacitor and the sampling resistor for the collector power supply Uc. The collector C forms an impedance R13 to the ground, and the capacitance to the ground is C13, which participates in the discharge process. During the power-off process, due to the interlock of step S01, the collector power supply Uc and the cathode power supply Uk are shut down synchronously, the power supply has no output, and the decrease in the high voltage between the collector C and the cathode K is the process of discharging the capacitance of the capacitors C11, C12, and C13.

[0018] As a further optimized technical solution, the capacitance of the capacitor C12 is the largest, much larger than C11, the capacitance of C11 is much larger than C13, and the capacitance of the capacitor C13 can be ignored. The time constant of the cathode discharge is: C11×(R12 + R13)×R11 / (R11 + R12 + R13), and the time constant of the collector discharge is: C12(R11 + R13)×R12 / (R11 + R12 + R13). To achieve the purpose of synchronous discharge, the two time constants are equal, that is:

[0019] C11×(R12 + R13)×R11 / (R11 + R12 + R13) = C12(R11 + R13)×R12 / (R11 + R12 + R13)

[0020] That is: C11×(R12 + R13)×R11 = C12(R11 + R13)×R12

[0021] The values of C11 and C12 are determined according to the operating parameters of the transmitter. To satisfy the above formula, appropriate resistance values are selected for R11, R12, and R13.

[0022] As a further optimized technical solution, in step S03, the output of the cathode power supply Uk is started in advance. After its energy storage capacitor C11 is charged to a certain potential, the collector power supply Uc is then turned on to charge the collector energy storage capacitor C12.

[0023] As a further optimized technical solution, the delay amount for turning on the collector power supply needs to satisfy the following:

[0024] Assume that the charging rate is approximately a linear function within a certain period of time. The cathode charging rate is K1, the collector charging rate is k2, the collector charging delay amount is T0, and the end time of the collector charging is T1. Then:

[0025] The peak negative voltage of the collector to the ground at time T0 is K1×T0

[0026] At time T1, the peak positive voltage of the collector to the ground is K2×(T1 - T0) - K1×T1

[0027] During the charging process, the potential of the collector to the ground is ensured to be less than the potential to the ground during normal operation, that is:

[0028] K1×T0 < Vk - Vc

[0029] K2×(T1 - T0) - K1×T1 < Vk - Vc

[0030] That is: T0 < (Vk - Vc) / K1

[0031] T1 < (K1 + K2)(Vk - Vc) / K1(K2 - K1)

[0032] The time of T1 is mainly determined by the output characteristics of the collector power supply Uc and the peripheral resistor-capacitor circuit. Adjust the initial delay time T0 to make the positive and negative voltage peaks of the collector with respect to the ground equal, that is, the peak potential with respect to the ground is the lowest.

[0033] Benfeng also provides a vacuum tube transmitter that adopts the method for preventing overvoltage impact on the collector during the power-on and power-off processes of a vacuum tube transmitter as described in any one of the above solutions.

[0034] The advantages of the present invention are as follows: In the case of a separate closed-loop design of the collector and cathode power supplies of a high-power vacuum tube transmitter, through the synchronous enabling of the cathode power supply and the collector power supply, fault interlocking, discharge time constant control, and charging delay design during the normal power-on, normal shutdown, and accidental power-off processes of the high-power vacuum tube transmitter, the collector power supply voltage and the cathode power supply voltage are kept synchronized to decrease during the shutdown or power-off process of the transmitter, and the collector power supply voltage and the cathode power supply voltage rise synchronously during the normal power-on process of the transmitter, avoiding the impact of power-on and power-off of the vacuum tube. When the power grid is powered off, the transmitter arcs, or there is an accidental power supply failure, the vacuum tube can be protected in a timely and effective manner, ensuring that the collector of the vacuum tube does not exceed the rated withstand voltage, improving the safety protection of the high-power transmitter, and increasing the service life of the vacuum tube and the long-term reliable operation of the high-power transmitter. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a circuit schematic diagram of an existing high-power vacuum tube;

[0036] Figure 2 is a schematic diagram of the synchronous control circuit for the collector power supply and the cathode power supply startup enable signal;

[0037] Figure 3 is a schematic diagram of the peripheral circuit of the high-power vacuum tube of the present invention;

[0038] Figure 4 is a schematic diagram of the process of the collector potential with respect to the ground decreasing during the power-off process;

[0039] Figure 5 is a schematic diagram of the process of the collector potential with respect to the ground rising during the power-on process. DETAILED DESCRIPTION OF THE INVENTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] Meanwhile, referring to Figure 1 and Figure 2 , the method for preventing overvoltage impact on the collector during the power-on and power-off processes of an electron tube transmitter of the present invention includes the following three steps:

[0042] S01. Ensure that the collector power supply Uc and the cathode power supply Uk of the electron tube transmitter are synchronized during startup and shutdown, and shut down in case of a fault in a chained manner, mainly to prevent the situation where only one power supply works.

[0043] S02. Ensure that the collector power supply voltage Vc and the cathode power supply voltage Vk of the electron tube transmitter decrease synchronously during the power-off process. With the guarantee of step S01, when powering off, the two power supplies will have no output simultaneously, and the energy storage capacitors of the collector C and the cathode K will discharge independently. It is necessary to design a suitable resistor-capacitor circuit to control the independent discharge time rate of the energy storage capacitors of the collector C and the cathode K to ensure that the collector C does not have overvoltage to the ground during the discharge process.

[0044] S03. When powering on at high voltage, the collector power supply Uc and the cathode power supply Uk charge the energy storage capacitors. After determining the resistor and capacitor in step S02, according to the charging speed of the two power supplies to the energy storage capacitors, determine the collector working delay circuit to ensure that the voltage of the collector C to the ground is within a safe range during the power-on process.

[0045] The following elaborates on each of the above steps.

[0046] Step S01. Ensure that the collector power supply Uc and the cathode power supply Uk of the electron tube transmitter are synchronized during startup and shutdown, and shut down in case of a fault in a chained manner:

[0047] According to the above analysis, when any one of the collector power supply Uc and the cathode power supply Uk works alone, it will cause the withstand voltage of the collector C to be insufficient. Therefore, it is necessary to synchronously control the startup enable signals of the collector power supply Uc and the cathode power supply Uk. As Figure 2 shown, a synchronous control circuit for the startup enable signals of the collector power supply and the cathode power supply is designed.

[0048] The synchronization control circuit for the collector power supply and the cathode power supply startup enable signal includes optocouplers V1, V2, V3, V4, resistors R1, R2, R3, and capacitors C1, C2. In this embodiment, the models of optocouplers V1, V2, V3, and V4 are TLP281-1.

[0049] Among them, port 1 of optocoupler V1 is connected to resistor R1, and the other end of resistor R1 serves as the startup enable signal input terminal. Port 2 of optocoupler V1 is connected to port 1 of optocoupler V2. Port 3 of optocoupler V1 serves as the cathode power supply enable signal output terminal, and port 4 of optocoupler V1 serves as the +15V power supply input terminal. Port 2 of optocoupler V2 is connected to port 4 of optocoupler V3. Port 3 of optocoupler V2 serves as the collector power supply enable signal output terminal, and port 4 of optocoupler V2 serves as the +15V power supply input terminal. Port 1 of optocoupler V3 is connected to resistor R2, and the other end of resistor R2 serves as the cathode power supply fault input terminal. Port 2 of optocoupler V3 is grounded. A capacitor C1 is connected between port 1 and port 2 of optocoupler V3. Port 3 of optocoupler V3 is connected to port 4 of optocoupler V4. Port 1 of optocoupler V4 is connected to resistor R3, and the other end of resistor R3 serves as the collector power supply fault input terminal. Port 2 of optocoupler V4 is grounded. A capacitor C2 is connected between port 1 and port 2 of optocoupler V4. Port 3 of optocoupler V4 is grounded.

[0050] The collector power supply Uc and the cathode power supply Uk use the same startup enable signal input. The cathode power supply startup enable, the collector power supply startup enable, the cathode power supply fault signal, and the collector power supply fault signal are connected in series through optocouplers V1, V2, V3, and V4. In this way, when any optocoupler is disconnected, the cathode power supply enable signal and the collector power supply enable signal will disappear simultaneously, ensuring the synchronous operation of the collector power supply Uc and the cathode power supply Uk. All levels are normal in the high level state, and the cathode power supply enable signal and the collector power supply enable signal can also be effectively disconnected when the circuit or other components are disconnected, ensuring the safety of power supply startup.

[0051] Through the above synchronization control circuit for the collector power supply and the cathode power supply startup enable signal, the synchronous startup and shutdown of the collector power supply Uc and the cathode power supply Uk can be achieved. When any one of the collector power supply Uc and the cathode power supply Uk fails, fast synchronous shutdown can be achieved, thereby preventing the situation where only a single power supply works.

[0052] S02. Ensure that during the power-off process, the collector power supply voltage Vc and the cathode power supply voltage Vk decrease synchronously. With the guarantee of step S01, when power is off, both power supplies will have no output simultaneously, and the energy storage capacitors of the collector C and the cathode K will discharge independently. It is necessary to design a suitable resistor-capacitor circuit to control the independent discharge time rate of the energy storage capacitors of the collector C and the cathode K to ensure that the collector C does not have overvoltage to the ground during the discharge process;

[0053] As Figure 3 shown, the designed resistor-capacitor circuit includes resistors R11, R12, impedance R13, and capacitors C11, C12, C13. Resistor R11 and capacitor C11 are connected in parallel between the cathode K and the tube body ground. Resistor R12 and capacitor C12 are connected in parallel between the cathode K and the collector C. An impedance R13 and a ground capacitance C13 are formed between the collector C and the tube body ground.

[0054] Resistor R11 and capacitor C11 are the energy storage capacitor and sampling resistor of the cathode power supply Uk. Resistor R12 and capacitor C12 are the energy storage capacitor and sampling resistor of the collector power supply Uc. Additionally, due to the reasons of collector sampling and distribution parameters, an impedance R13 is formed between the collector C and the ground, and the ground capacitance is C13, which also participates in the discharge process. Considering the system working principle of the transmitter, the working current of the collector C (provided by the collector power supply Uc) is much larger than the working current of the tube body B (provided by the cathode power supply Uk). Therefore, the capacitance C12 has the largest capacity, much larger than C11, and the capacity of C11 is much larger than C13.

[0055] During the power-off process, due to the interlock of step S01, the collector power supply Uc and the cathode power supply Uk can achieve synchronous shutdown, that is, the power supply has no output. The decrease in the high voltage of the collector C and the cathode K is the process of discharging the capacitor charges on the above capacitors C11, C12, and C13. Here, the capacitance C13 is too small and can be basically ignored. Thus, it is approximately considered that the time constant of the cathode discharge is: C11×(R12 + R13)×R11 / (R11 + R12 + R13), and the time constant of the collector discharge is: C12(R11 + R13)×R12 / (R11 + R12 + R13); To achieve the purpose of synchronous discharge, the two time constants should be basically equal, that is:

[0056] C11×(R12 + R13)×R11 / (R11 + R12 + R13) = C12(R11 + R13)×R12 / (R11 + R12 + R13)

[0057] That is: C11×(R12 + R13)×R11 = C12(R11 + R13)×R12

[0058] Here, the values of C11 and C12 are usually determined according to the operating parameters of the transmitter. Therefore, to satisfy the above equation, appropriate resistance values can be selected for R11, R12, and R13. In particular, the resistance value of R13 can have a relatively large adjustment range.

[0059] By the above method, the discharge times of C11 and C12 are made consistent. Then, the voltage of the collector electrode with respect to the ground gradually changes from the value of Vk - Vc during operation to 0, as Figure 4 shown, and the phenomenon of overvoltage of the collector electrode tube body with respect to the ground will not occur during the power-off process.

[0060] Step S03: When high voltage is powered on, the collector power supply Uc and the cathode power supply Uk charge the energy storage capacitor. After determining the resistance and capacitance in step S02, according to the charging speeds of the two power supplies to the energy storage capacitor, the collector working delay circuit is determined to ensure that the voltage of the collector C with respect to the ground is within a safe range during the power-on process.

[0061] After completing the control of the voltage drop process during power-off and determining the resistance and capacitance values, the design of the voltage rise control during startup can be carried out. During the power-on process, since the working current of the collector power supply Uc is much larger than that of the cathode power supply Uk, the charging speed of the collector power supply Uc output to the energy storage capacitor C12 is very fast. If the collector power supply Uc and the cathode power supply Uk output simultaneously, the energy storage capacitor C12 of the collector voltage will be quickly filled, while the energy storage capacitor C11 of the cathode voltage does not increase sufficiently at the same time. This also leads to an excessive Vc - Vk, that is, the reverse positive voltage of the collector C with respect to the ground is too high, and there is a possibility of exceeding the breakdown voltage of the collector K with respect to the ground.

[0062] Therefore, the output of the cathode power supply Uk is started in advance. After charging its energy storage capacitor C11 to a certain potential (lower than the breakdown voltage of the collector with respect to the ground), the collector power supply Uc is then turned on to charge the energy storage capacitor C12 of the collector. After it is quickly filled, although the potential of the collector with respect to the ground may also be a reverse positive voltage, the amplitude will be greatly reduced. And as the potential of the energy storage capacitor C11 of the cathode voltage slowly increases, it begins to gradually decrease and finally stabilizes at the potential during normal operation, as Figure 5 shown.

[0063] The delay amount for turning on the collector power supply needs to satisfy the following:

[0064] Assume that the charging rate is approximately a linear function within a certain period of time. The cathode charging rate is K1, the collector charging rate is k2, the collector charging delay amount is T0, and the end time of collector charging is T1. Then:

[0065] The peak value of the negative voltage of the collector with respect to the ground at time T0 is K1 × T0

[0066] At time T1, the peak value of the positive voltage of the collector with respect to the ground is K2 × (T1 - T0) - K1 × T1

[0067] Generally, it is only necessary to consider that the potential of the collector with respect to the ground is within the safe withstand voltage range. However, in order to minimize voltage surges and extend the service life of the electron tube, during the charging process, the potential of the collector with respect to the ground can be designed to be less than the potential with respect to the ground during normal operation. That is:

[0068] K1×T0<Vk - Vc

[0069] K2×(T1 - T0)-K1×T1<Vk - Vc

[0070] That is: T0<(Vk - Vc) / K1

[0071] T1<(K1 + K2)(Vk - Vc) / K1(K2 - K1)

[0072] Here, the time of T1 is mainly determined by the output characteristics of the collector power supply Uc and the resistive-capacitive circuit determined by the periphery. The initial delay time T0 is mainly adjusted so that the positive and negative voltage peaks of the collector with respect to the ground are basically equal, that is, the peak potential with respect to the ground is the lowest.

[0073] The embodiments of the present invention are directed to single-collector electron tubes, and this protection method is also of reference significance for multi-collector ones.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter, characterized in that: It includes the following three steps: S01, ensure that the collector power supply Uc and cathode power supply Uk of the vacuum tube transmitter are turned on and off synchronously, and the fault chain shutdown is carried out to prevent the situation where only one power supply is working; S02, ensuring that the collector power supply voltage Vc and the cathode power supply voltage Vk of the electric vacuum tube transmitter are synchronously adjusted down during the power-off process. After step S01, when the power is off, the two power supplies will have no output at the same time, and the energy storage capacitors of the collector C and the cathode K will discharge autonomously at the same time. The resistor-capacitor circuit is designed to control the autonomous discharge time rate of the energy storage capacitors of the collector C and the cathode K to ensure that the collector C is not over-pressurized to the ground during the discharge process; S03. When the high voltage is powered on, the collector power supply Uc and the cathode power supply Uk charge the energy storage capacitor. According to the charging speed of the two power supplies to the energy storage capacitor, the collector working delay circuit is determined to ensure that the collector C voltage to ground is within a safe range during the power-on process.

2. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 1, characterized in that: In the step S01, it is necessary to synchronously control the power-on enable signals of the collector power supply Uc and the cathode power supply Uk.

3. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 2, characterized in that: Design a collector power supply and cathode power supply start-up enable signal synchronization control circuit, including photoelectric couplers V1, V2, V3, V4, resistors R1, R2, R3, capacitors C1, C2; Port 1 of the photoelectric coupler V1 is connected to the resistor R1, and the other end of the resistor R1 is used as the power-on enable signal input terminal, port 2 of the photoelectric coupler V1 is connected to port 1 of the photoelectric coupler V2, port 3 of the photoelectric coupler V1 is used as the cathode power enable signal output terminal, and port 4 of the photoelectric coupler V1 is used as the +15V power input terminal; port 2 of the photoelectric coupler V2 is connected to port 4 of the photoelectric coupler V3, port 3 of the photoelectric coupler V2 is used as the collector power enable signal output terminal, and port 4 of the photoelectric coupler V2 is used as the +15V power input terminal; Port 1 of the coupler V3 is connected to the resistor R2, the other end of the resistor R2 serves as a cathode power supply fault input terminal, port 2 of the photoelectric coupler V3 is grounded, capacitor C1 is connected between ports 1 and 2 of the photoelectric coupler V3, and port 3 of the photoelectric coupler V3 is connected to port 4 of the photoelectric coupler V4; port 1 of the photoelectric coupler V4 is connected to the resistor R3, the other end of the resistor R3 serves as a collector power supply fault input terminal, port 2 of the photoelectric coupler V4 is grounded, capacitor C2 is connected between ports 1 and 2 of the photoelectric coupler V4, and port 3 of the photoelectric coupler V4 is grounded.

4. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 3, characterized in that: In this embodiment, the model of the photoelectric couplers V1, V2, V3, and V4 is TLP281-1.

5. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 3, characterized in that: All levels are normally high, and the cathode power enable signal and the collector power enable signal can be disconnected when the line or other devices are disconnected.

6. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 1, characterized in that: In the step S02, the designed resistance-capacitance circuit includes resistors R11, R12, impedance R13, capacitors C11, C12, and C13, the resistor R11 and the capacitor C11 are connected in parallel between the cathode K and the tube body ground, the resistor R12 and the capacitor C12 are connected in parallel between the cathode K and the collector C, and the collector C and the tube body ground form an impedance R13 and a capacitor C13 to ground; Resistor R11 and capacitor C11 are energy storage capacitors and sampling resistors of the cathode power supply Uk, resistor R12 and capacitor C12 are energy storage capacitors and sampling resistors of the collector power supply Uc, the collector C forms an impedance R13 to the ground, and the capacitance to the ground is C13, which participates in the discharge process. During the power-off process, due to the interlocking of step S01, the collector power supply Uc and the cathode power supply Uk are shut down synchronously, the power supply has no output, and the drop in the high voltage of the collector C and the cathode K is the release process of the capacitive charge on capacitors C11, C12, and C13.

7. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 6, characterized in that: The capacity of capacitor C12 is the largest, much larger than C11. The capacity of C11 is much larger than C13. The capacity of capacitor C13 is negligible. The time constant of cathode discharge is: C11×(R12+R13)×R11 / (R11+R12+R13), and the time constant of collector discharge is: C12(R11+R13)×R12 / (R11+R12+R13). To achieve the purpose of synchronous discharge, the two time constants are equal, that is: C11×(R12+R13)×R11 / (R11+R12+R13)=C12(R11+R13)×R12 / (R11+R12+R13) That is: C11×(R12+R13)×R11=C12(R11+R13)×R12 The values ​​of C11 and C12 are determined according to the operating parameters of the transmitter. To satisfy the above formula, appropriate resistance values ​​are selected for R11, R12, and R13.

8. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 1, characterized in that: In step S03, the cathode power supply Uk is started to output in advance, and after its energy storage capacitor C11 is charged to a certain potential, the collector power supply Uc is turned on to charge the collector energy storage capacitor C12.

9. A method for preventing collector overvoltage shock during power-on and power-off of a vacuum tube transmitter as claimed in claim 8, characterized in that: The collector power on delay must meet the following requirements: Assume that the charging rate over a period of time is approximately a linear function, the cathode charging rate is K1, the collector charging rate is k2, the collector charging delay is T0, and the collector charging is completed at T1, then: The peak negative pressure of the collector to the ground at time T0 is K1×T0 At T1, the peak positive voltage of the collector to ground is K2×(T1-T0)-K1×T1 During the charging process, the potential of the collector electrode to the ground is guaranteed to be less than the potential to the ground during normal operation, that is: K1×T0 <Vk-Vc K2×(T1-T0)-K1×T1 <Vk-Vc That is: T0 < (Vk-Vc) / K1 T1<(K1+K2)(Vk-Vc) / K1(K2-K1) The time of T1 is mainly determined by the output characteristics of the collector power supply Uc and the peripheral resistance and capacitance circuit. The initial delay time T0 is adjusted to make the peak values ​​of the positive and negative voltages of the collector to the ground equal, that is, the peak potential to the ground is the lowest.

10. A vacuum tube transmitter using the method for preventing collector overvoltage shock during power-on and power-off of the vacuum tube transmitter as claimed in any one of claims 1 to 9.

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