Thermal load management method and system for multi-tube ECRH system operating on low power basis

Abstract

The application provides a multi-tube ECRH system thermal load management method based on low-power foundation operation, belongs to the field of electron cyclotron resonance heating systems, and sequentially starts the gyrotron to the foundation power; when the target total power and operation duration are received, a time period is determined, one gyrotron is scheduled as a rest tube in turn, and the rest gyrotrons are working tubes; the operation power and collector temperature of each gyrotron are periodically collected, the cumulative thermal load of each gyrotron is calculated, at the end of each time window, the thermal load relative deviation of each gyrotron is calculated based on the average thermal load of all gyrotrons, the gyrotron with the thermal load relative deviation exceeding a threshold value is marked as a to-be-adjusted gyrotron, the adjustment amount is calculated according to the thermal load relative deviation of the to-be-adjusted gyrotron, the operation power of the to-be-adjusted gyrotron is adjusted, and the operation power of all working tubes is dynamically adjusted; and the thermal load management system is also provided; the contradiction between fast response and thermal management, power stability and thermal balance is broken through.

Description

Technical Field

[0001] This invention relates to the field of electron cyclotron resonance heating (ECRH) system technology, and in particular to a method and system for heat load management of multi-tube ECRH systems based on low-power operation. Background Technology

[0002] Electron cyclotron resonance heating is an important auxiliary heating method in magnetic confinement fusion devices, heating electrons through resonance between high-frequency electromagnetic waves and plasma. As fusion research moves towards longer pulses, modern fusion devices generally employ multi-tube coordinated operation to achieve high power output. For example, the International Thermonuclear Experimental Reactor (ITER) plans to use 24 170 GHz cyclotrons with a total power of 24 MW; the Experimenta Advanced Superconducting Tokamak (EAST) is equipped with 4 140 GHz cyclotrons with a total power of 4 MW; and the W7-X is equipped with 10 140 GHz cyclotrons with a total power of 10 MW. While providing high power, multi-tube coordinated operation also brings complex control and thermal management challenges.

[0003] The existing technologies mainly operate in the following modes:

[0004] (1) Standby-start operation mode: The gyrotube remains in standby mode during the plasma discharge gap and is activated only when needed. The drawbacks of this operation mode are: the cold start process requires 30 to 60 seconds to preheat the cathode to the operating temperature (1800K-2000K), which cannot meet the plasma control requirement for rapid response (less than 5 seconds). The abrupt change from zero power to rated power (0.8MW-1MW) generates severe thermal shock, and components such as the collector electrode and output window are subjected to huge thermal stress instantly, accelerating the fatigue aging of the components. The inconsistent start-up time of each tube in the multi-tube system leads to fluctuations in the total power, affecting plasma stability.

[0005] (2) Constant power operation mode: All gyroscopes operate continuously at a preset power, which is simple to control. However, during long pulse operation, the heat load of key components accumulates continuously, and due to differences in cooling conditions, component characteristics, and initial state of each tube, the heat load distribution gradually becomes uneven. After 1000 seconds of constant power operation of the EAST device's 4-tube system, the heat load deviation of each tube reaches 30%-40%, and some tubes approach the thermal limit of 400°C in advance, forcing them to reduce power or shut down, thus limiting the ability to operate continuously. In addition, this operation mode lacks a dynamic modulation mechanism, and when a tube overheats, the system power can only be reduced as a whole.

[0006] (3) Intermittent operation strategy: thermal load is controlled by periodically starting and stopping the gyrotron. For example, EAST uses a strategy of running for 500 seconds, then shutting down for cooling and restarting in long-pulse simulation. This method alleviates heat accumulation, but each restart requires a complete cold start (30-60 seconds), resulting in a slow response speed. The drastic power changes during the start-up and shutdown process (e.g., 0→0.8 MW→0) introduce additional thermal shock, accelerating component fatigue. In addition, the total power fluctuation during switching can reach ±20%, affecting plasma control and potentially leading to rupture.

[0007] (4) Off-peak start-up sequence: The 10-tube system of W7-X starts up sequentially, with intervals of several seconds to tens of seconds, to disperse the thermal transients and power surges during the start-up phase. This strategy only solves the start-up problem and lacks system management for the accumulation and uneven distribution of heat load during steady-state long-pulse operation. Each tube still needs a cold start, and the total start-up time of the system actually increases. During operation, it is impossible to make dynamic adjustments according to the actual heat load status.

[0008] It is evident that existing technologies suffer from the following common problems: (1) contradiction between rapid response and thermal management: standby mode has low energy consumption but slow response, while continuous operation has a fast response but severe heat accumulation; (2) contradiction between power stability and thermal balance: constant power mode has stable total power but uneven heat load, while intermittent operation attempts to balance the heat load but has large power fluctuations; (3) lack of systematic solutions: most optimizations are localized for single problems without comprehensively considering rapid response, thermal load balance, and power stability; (4) poor scalability: designed for a specific number of tubes, the control complexity increases sharply when expanded to a large-scale system (e.g., 24 tubes). These problems significantly restrict the performance of multi-tube ECRH systems in long-pulse operation. Summary of the Invention

[0009] The technical problem to be solved by this invention is: how to solve the problem that multi-tube ECRH systems cannot simultaneously achieve fast response, thermal load balance and power stability during long pulse operation.

[0010] This invention solves the above-mentioned technical problems through the following technical solution: a method for heat load management of a multi-tube ECRH system based on low-power operation, the method comprising:

[0011] The gyrotubes in the multi-tube ECRH system are sequentially started up to base power, and each gyrotube continues to operate at base power.

[0012] When the target total power and running time required for plasma heating are received, the time period is determined according to the running time and time window. During all time periods, one cyclotron is rotated as the resting tube and the remaining cyclotrons are the working tubes. The resting tube runs continuously at the base power and the working tubes run continuously at the working power. During the transition period between adjacent time periods, the power change rate of the resting tube from the base power to the working power is the same as the power change rate of the working tube from the working power to the base power.

[0013] The operating power and collector temperature of each gyroscope are periodically collected, and the cumulative heat load of each gyroscope is calculated. At the end of each time window, based on the average heat load of all gyroscopes, the relative deviation of the heat load of each gyroscope is calculated. Gyroscopes with a relative heat load deviation exceeding the threshold are marked as gyroscopes to be adjusted. The adjustment amount is calculated based on the relative heat load deviation of the gyroscopes to be adjusted, and the operating power of the gyroscopes to be adjusted is adjusted based on the adjustment amount. The operating power of all working tubes is dynamically adjusted according to the time period to keep the target total power constant.

[0014] This invention aims to overcome the contradictions between rapid response and thermal management, and between power stability and thermal balance in existing technologies through the coordinated design of low-power base operation and time-sharing thermal load management. Low-power base operation solves the rapid response problem, keeping the gyrotrons in a hot standby state, significantly reducing cold start delay and achieving rapid power response. Low-power base operation can also reduce thermal shock caused by power surges and extend component life. Time-sharing scheduling solves the thermal load balance problem, ensuring fair distribution by having each gyrotron experience the same operating mode, avoiding overheating of some gyrotrons. Symmetrical synchronous transition solves the power stability problem, ensuring a constant total power during switching. Dynamic balance control solves the actual deviation problem, achieving precise balance in long-term operation.

[0015] Preferably, the time period is determined based on runtime and time window as follows:

[0016]

[0017] in, For time period, This indicates the floor function. For runtime, For time windows.

[0018] Preferably, one rotary tube is rotated as a resting tube throughout all time periods. for:

[0019]

[0020] in, For time period, The number of rotary tubes, Modulo operation.

[0021] Preferably, each gyrotube is a first gyrotube to a second gyrotube. Rotary tube, The number of gyrotubes, with all time periods including the first time period in sequence. To the Time period , For time period, The time window is defined as follows: each time period includes a power regulation phase and a steady-state operation phase. During the power regulation phase of the first time period, the first gyrotron maintains its base power, while the second gyrotron... The gyrotron increases from base power to operating power at a rate of power change. During the steady-state operation phase of the first time period, the first gyrotron operates continuously at base power, while the second gyrotron... The gyrotubes operate continuously at their operating power; during the power adjustment phase of the second time period, the first gyrotube increases from its base power to its operating power at a rate of power change, the second gyrotube decreases from its operating power to its base power at a rate of power change, and the third gyrotube... The gyrotron operates continuously at its operating power. During the steady-state operation phase of the second time period, the second gyrotron operates continuously at its base power, while the first, third, and subsequent gyrotrons operate continuously at their base power. The gyrotron operates continuously at its working power; and so on, in the... During the power regulation phase of the time period, the first The gyrotron increases from base power to operating power at a rate of power change. The gyrotron decreases from its operating power to its base power at a rate of power change, from the first gyrotron to the second. The gyrotron operates continuously at its working power, in the first... During the steady-state operation phase of the time period, the first The gyrotron operates continuously at base power, from the first gyrotron to the second. The gyrotube operates continuously at its working power.

[0022] This invention proposes a power-level switching mechanism, distinct from the start-stop switching (complete shutdown) of existing technologies. It proposes a design principle where the number of time windows equals the number of transistors (N), ensuring that each transistor experiences the same working-rest ratio. A method for selecting the time window length based on the thermal time constant is also proposed. Furthermore, a symmetrical synchronous power transition design is introduced, where the power of the boost and deboost transistors changes synchronously according to a linear law at the switching moment, and the sum of the power of the two transistors remains constant, transforming the total power stability problem into a problem of power complementarity between the two transistors.

[0023] Preferably, the cumulative heat load of each rotary tube for:

[0024]

[0025] in, For a moment The first collection The operating power of each gyrotube The collection period, The total number of data collections within a time window. For a moment The first collection Temperature of the gyrotube The corresponding temperature weighting function, , For reference temperature, For parameters.

[0026] This invention incorporates temperature factors into the heat load calculation, and the temperature weighting function adopts an exponential form to better reflect the nonlinear acceleration effect of high-temperature damage. Existing technologies usually only consider power integrals and ignore the influence of temperature.

[0027] Preferably, the process of calculating the relative deviation of the heat load of each gyro tube based on the average heat load of all gyro tubes includes:

[0028] Calculate the average heat load of all rotary tubes. :

[0029]

[0030] in, For the first The cumulative heat load of each rotary tube at the end of the current time window The number of rotary tubes;

[0031] Calculate the first Relative deviation of heat load of each rotary tube :

[0032] .

[0033] Preferably, the process of calculating the adjustment amount based on the relative deviation of the heat load of the rotary tube to be adjusted, and adjusting the operating power of the rotary tube to be adjusted based on the adjustment amount includes:

[0034] The adjustment amount is calculated based on the relative deviation of the heat load of the rotary tube to be adjusted. :

[0035]

[0036] in, For the rotary tube to be adjusted The relative deviation of heat load, , The number of rotary tubes, This is the gain coefficient. Operating power;

[0037] If the gyro tube to be adjusted is the working tube within the current time window, adjust the operating power of the gyro tube to be adjusted. for: If the gyro tube to be adjusted is in a resting state within the current time window, adjust the operating power of the gyro tube to be adjusted. for: Rest power It equals the base power.

[0038] Preferably, the process of dynamically adjusting the operating power of all working tubes according to the time period includes:

[0039] Calculate the total adjustment amount :

[0040]

[0041] in, For the rotary tube to be adjusted The adjustment amount, The number of rotary tubes to be adjusted;

[0042] Based on the total adjustment amount Calculate the compensation amount based on the number of working pipes. for: , The number of rotary tubes;

[0043] The operating power of the gyrotube to be adjusted during the current time period. Adjusted to The power of the operating transistor at its operating power. Adjusted to The rest tube maintains its base power unchanged;

[0044] Determine whether the operating power of the adjusted working tube exceeds the upper limit of the operating power. If the working tube exceeds the upper limit of the operating power, it will operate at the upper limit of the operating power. If the working tube does not exceed the upper limit of the operating power, it will share the remaining power equally. The remaining power is the operating power of the adjusted working tube minus the upper limit of the operating power.

[0045] This invention proposes a normalized dynamic adjustment mechanism based on the relative deviation of heat load. Calculate adjustment amount Then, normalization is performed to ensure that the sum of the adjustments is zero, maintaining a constant total power. This mechanism allows the heat load deviation to converge from 20-30% to within 5% within 2-3 operating cycles, and the algorithm complexity supports linear expansion.

[0046] Preferably, the cumulative heat load of any one rotary tube within a running time is... for:

[0047]

[0048] in, The operating time of a gyrotube within one operating cycle. , The rest time for a rotary tube during one operating cycle. Time window , Working power, resting power Equal to base power, This represents the number of rotary tubes.

[0049] This invention achieves complete balance through time-sharing heat load management by periodically rotating each rotary tube to experience the same operating mode.

[0050] This invention also provides a heat load management system for a multi-tube ECRH system based on low-power operation, the system comprising:

[0051] The initialization module is used to sequentially start the gyrotrons in the multi-tube ECRH system to base power, and each gyrotron continues to operate at base power.

[0052] The time-sharing scheduling module is used to determine the time period based on the running time and time window when the target total power and running time required for plasma heating are received. During all time periods, one cyclotron is scheduled as the rest tube and the rest tubes are the working tubes. The rest tube runs continuously at the base power and the working tubes run continuously at the working power. During the transition period between adjacent time periods, the power change rate of the rest tube from the base power to the working power is the same as the power change rate of the working tube from the working power to the base power.

[0053] The heat load balancing control module is used to periodically collect the operating power and collector temperature of each gyroscope, calculate the cumulative heat load of each gyroscope, and at the end of each time window, calculate the relative heat load deviation of each gyroscope based on the average heat load of all gyroscopes. Gyroscopes with a relative heat load deviation exceeding a threshold are marked as gyroscopes to be adjusted. The adjustment amount is calculated based on the relative heat load deviation of the gyroscopes to be adjusted, and the operating power of the gyroscopes to be adjusted is adjusted based on the adjustment amount. The operating power of all working tubes is dynamically adjusted according to the time period to keep the target total power constant. Attached Figure Description

[0054] Figure 1 A flowchart illustrating the thermal load management method for a multi-tube ECRH system based on low-power base operation, provided in Embodiment 1 of the present invention;

[0055] Figure 2 This is a schematic diagram of a 4-tube ECRH system that adopts the heat load management method for a multi-tube ECRH system based on low-power operation in Example 1, as described in Example 2.

[0056] Figure 3 This is the time-sharing heat load management operation sequence diagram of a 4-tube ECRH system that adopts the heat load management method for a multi-tube ECRH system based on low-power operation in Example 1 in Example 2;

[0057] Figure 4 This is a schematic diagram of the smooth power transition during time period switching of a 4-tube ECRH system using the heat load management method for a multi-tube ECRH system based on low-power operation in Example 1, as described in Example 2.

[0058] Figure 5 This is a schematic diagram of a multi-tube ECRH system heat load management system based on low-power operation, provided for Embodiment 3 of the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0060] Example 1

[0061] like Figure 1 As shown, this embodiment provides a method for heat load management of a multi-tube ECRH system operating on a low-power basis, including the following steps:

[0062] Step 1: Sequentially start the gyrotrons in the multi-tube ECRH system to base power, and each gyrotron will continue to operate at base power. For example, in a multi-tube ECRH system, there are a total of Taking a gyrotron with a base power of 0.2MW as an example, in actual operation, a staggered peak-shifting strategy is adopted to start it up sequentially. The gyrotron is started up to a base power of 0.2MW, with a 10-second start-up interval between adjacent gyrotrons to avoid power surges. The specific process for starting the gyrotron to the base power of 0.2MW is as follows: the predicted heating power of the gyrotron cathode is 10kW, the prediction time is 60 seconds, and the cathode temperature is designed to rise to approximately 1400K. The gyrotron anode voltage is gradually increased from 0 to 20kV, with a beam current of 0.5A. A PI controller can be used to adjust the gyrotron cathode voltage to stabilize the output power at the base power of 0.2MW. At this point, the gyrotron collector temperature is approximately 150℃, and the output window temperature is 100℃. Once all gyrotubes have started up, the multi-tube ECRH system enters hot standby mode. Each gyrotron operates continuously at a base power of 0.2MW, with a total system power of 0.8MW. The cathode temperature of each gyrotron is maintained at 1400K-1500K to preserve electron emission capability, and the collector and output windows are in thermal equilibrium. The system is in hot standby mode awaiting a plasma start-up signal.

[0063] Low-power base operation keeps each gyrotron continuously operating at base power, ensuring that key components of each gyrotron are always kept warm. The cathode temperature of each gyrotron is maintained at a specific temperature—above the electron emission threshold but below the rated operating temperature—ensuring the electron gun is in a warm, stable operating state. The collector and output window are expected to be in thermal equilibrium. This expected thermal state allows the gyrotron to accelerate from base power to operating power with only minor adjustments to the cathode voltage or anode current, eliminating the need for a full startup process involving cathode preheating, component thermal expansion and contraction, and space charge establishment. This significantly reduces cold-start delay and enables rapid power response. Furthermore, taking a base power of 0.2MW as an example, during base power operation, the gyrotron collector temperature is approximately 150°C. Compared to the existing standby-start operation mode (where the gyrotron collector temperature is approximately room temperature, around 20°C), in low-power base operation, the collector temperature rises from 150°C to 350°C with a temperature gradient of only 200K. This significantly reduces thermal stress during startup, and the smaller temperature gradient further reduces localized stress concentration.

[0064] Step 2: When the target total power required for plasma heating is received... and runtime At that time, based on runtime and time window Judgment period During all time periods, one rotary tube is rotated as the resting tube, and the remaining rotary tubes are the working tubes. The resting tube operates at its base power. Continuous operation, operating power During continuous operation, and the transition period between adjacent time slots, the rest tube operates from base power. Increase to operating power power change rate With working power Reduced to base power power change rate same.

[0065] Among them, based on runtime and time window Judgment period for:

[0066]

[0067] in, This indicates the floor function. For runtime, For time windows.

[0068] Rotate one rotary tube as the resting tube in all time periods. for:

[0069]

[0070] in, For time period, The number of rotary tubes, Modular operation. Based on the number of gyrotubes. 4. Runtime 1000 seconds, time window Taking 250 seconds as an example, the time period The value can be 0, 1, 2, or 3. When the value is 0, it corresponds to the first time period, at which point the resting tube is the first spiral tube. When the value is 1, it corresponds to the second time period, at which time the resting tube is the second spiral tube. When the value is 2, it corresponds to the third time period, at which point the resting tube is the third spiral tube. When the value is 3, it corresponds to the fourth time period, and at this time the rest tube is the fourth spiral tube.

[0071] Each gyrotube is from the first gyrotube to the second gyrotube. Rotary tube, all time periods including the first time period in sequence To the Time period Each time period corresponds to a time window, and the number of time windows equals the total number of cyclotrons, ensuring that each cyclotron experiences the same working-rest ratio. The length of the time window is determined based on the thermal time constant. Each time period includes a power regulation phase and a steady-state operation phase. The power regulation phase is the transition period between adjacent time periods. During the power regulation phase of the first time period, the first cyclotron maintains its base power, while the second cyclotron... The gyrotube changes power at a rate of From base power Increase to operating power During the steady-state operation phase of the first time period, the first gyrotron operates at its base power. Continuing operation, from the second gyro to the first The gyrotube operates at power Continuous operation; during the power regulation phase of the second time period, the first gyrotube operates at a power change rate From base power Increase to operating power The second gyrotron changes power at a rate of From operating power Reduced to base power The third gyrotube to the first The gyrotube operates at power During continuous operation, in the steady-state operation phase of the second time period, the second gyrotron operates at its base power. Continuing operation, the first gyrotube, the third gyrotube, and so on... The gyrotube operates at power Continue running; and so on, until the... During the power regulation phase of the time period, the first The gyrotube changes power at a rate of From base power Increase to operating power , No. The gyrotube changes power at a rate of From operating power Reduced to base power The first gyrotube to the first The gyrotube operates at power Continuously running, in the During the steady-state operation phase of the time period, the first gyrotron at base power Continuous operation, from the first gyro to the second The gyrotube operates at power Continuous operation. During the transition period between adjacent time slots, a symmetrical synchronous power transition design is adopted, that is, the resting tube switches from the base power... Increase to operating power power change rate With working power Reduced to base power power change rate Similarly, the power of the power-up gyroscope and the power-down gyroscope changes synchronously according to a linear law at the switching moment, and the sum of the power of the two gyroscopes remains constant, thereby maintaining the stability of the total power.

[0072] Step 3: Periodically collect the operating power and collector temperature of each gyrotron, and calculate the cumulative heat load of each gyrotron. At the end of each time window, based on the average heat load of all cyclotrons Calculate the relative deviation of heat load for each rotary tube. The relative deviation of heat load Rotary tubes exceeding the threshold are marked as rotary tubes to be adjusted, and the adjustment amount is calculated based on the relative deviation of the heat load of the rotary tubes to be adjusted. Based on adjustment amount Adjust the operating power of the gyrotube to be adjusted. The operating power of all working tubes is dynamically adjusted according to the time period to keep the target total power constant.

[0073] Step 3.1: Cumulative heat load of each rotary tube for:

[0074]

[0075] in, For a moment The first collection The operating power of each gyrotube The collection period, The total number of data collections within a time window. For a moment The first collection Temperature of the gyrotube The corresponding temperature weighting function, , For reference temperature, For parameters.

[0076] Step 3.2: Based on the average heat load of all rotary tubes Calculate the relative deviation of heat load for each rotary tube. The process includes:

[0077] Step 3.2.1: Calculate the average heat load of all rotary tubes. :

[0078]

[0079] in, For the first The cumulative heat load of each rotary tube at the end of the current time window This represents the number of rotary tubes.

[0080] Step 3.2.2, calculate the first... Relative deviation of heat load of each rotary tube :

[0081]

[0082] Step 3.3: Calculate the adjustment amount based on the relative deviation of the heat load of the rotary tube to be adjusted. Based on adjustment amount Adjust the operating power of the gyrotube to be adjusted. The process includes:

[0083] Step 3.3.1: Based on the relative deviation of the heat load of the rotary tube to be adjusted. Calculate the adjustment amount :

[0084]

[0085] in, For the rotary tube to be adjusted The relative deviation of heat load, , This is the gain coefficient. This refers to the operating power.

[0086] Step 3.3.2: If the gyro tube to be adjusted is the working tube within the current time window, adjust the operating power of the gyro tube to be adjusted. for: If the gyro tube to be adjusted is in a resting state within the current time window, adjust the operating power of the gyro tube to be adjusted. for: ; This is the resting power, which is equal to the base power, in order to maintain the system in a hot standby state.

[0087] Step 3.4, the process of dynamically adjusting the operating power of all working tubes according to the time period, includes:

[0088] Step 3.4.1: Calculate the total adjustment amount :

[0089]

[0090] in, For the rotary tube to be adjusted The adjustment amount, The number of rotary tubes to be adjusted;

[0091] Step 3.4.2: Based on the total adjustment amount Calculate the compensation amount based on the number of working pipes. for:

[0092]

[0093] in, This represents the number of rotary tubes.

[0094] Step 3.4.3: Adjust the operating power of the gyrotube to be adjusted within the current time period. Adjusted to The power of the operating transistor at its operating power. Adjusted to The rest tube maintains its base power unchanged;

[0095] Step 3.4.4: Determine whether the operating power of the adjusted working tube exceeds the upper limit of the working power. If it exceeds the upper limit of the working power, a limiting process is required. The limiting process is as follows: the working tube that exceeds the upper limit of the working power operates at the upper limit of the working power, and the working tube that does not exceed the upper limit of the working power shares the remaining power equally. The remaining power is the operating power of the adjusted working tube minus the upper limit of the working power.

[0096] By periodically rotating each rotary tube to experience the same operating mode, time-sharing heat load management of all rotary tubes in a multi-tube ECRH system can be achieved. Ideally, The operating time of each gyrotube Divided into Each time window for:

[0097]

[0098] Within each time window, one cyclotron rests, and the rest... One gyrotron operates, during one operating time Inside, neglecting temperature differences, the cumulative heat load of any rotary tube for:

[0099]

[0100] in, The operating time of a gyrotube within one operating cycle. , The rest time for a rotary tube during one operating cycle. .

[0101] This invention aims to overcome the contradictions between rapid response and thermal management, and between power stability and thermal balance in existing technologies through the coordinated design of low-power base operation and time-sharing thermal load management. Low-power base operation solves the rapid response problem, keeping the gyrotrons in a hot standby state, significantly reducing cold start delay and achieving rapid power response. Low-power base operation also reduces thermal shock caused by power surges, extending component lifespan. Time-sharing scheduling solves the thermal load balance problem, ensuring fair distribution by having all gyrotrons experience the same operating mode, preventing overheating of some gyrotrons. Symmetrical synchronous transition solves the power stability problem, ensuring a constant total power during switching. Dynamic balance control solves the actual deviation problem, achieving precise balance in long-term operation. These four elements support each other to form a complete system solution.

[0102] Low-power base operating mode: This invention proposes that all gyrotrons continuously operate at base power. Basic power equal to rest power Maintain hot standby status, based on base power. Taking 0.2 MW as an example, the base power is 20-30% of the rated power, maintaining the thermal state of key components, which differs from the standby mode (zero power) and rated power operation of existing technologies. The cathode temperature is designed to be maintained at 1400-1500 K, higher than the electron emission threshold of 1200 K, and the collector temperature is maintained at 150-180℃ to achieve thermal equilibrium, reducing the power regulation response time from 30-60 seconds to less than 5 seconds, improving the response speed by more than 80%. This invention clarifies the basis for selecting the base power and quantifies its relationship with the temperature of key components, providing a theoretical basis for parameter configuration. Although this mode increases the base power consumption by 0.8 MW, it eliminates cold start delay and reduces thermal shock caused by power surges, extending component life (temperature gradient reduced from 330 K to 200 K), laying the foundation for the entire thermal load management scheme.

[0103] Coordinated Design of Time-Sharing Scheduling and Symmetrical Synchronous Power Transition: This invention proposes a power tiered rotation system (rest power equals the base power of 0.2 MW for hot standby), distinct from the start-stop rotation system (complete shutdown) of existing technologies. It proposes a design principle where the number of time windows equals the number of tubes N, ensuring that each tube experiences the same working-rest ratio, and proposes a method for selecting the time window length based on the thermal time constant. More importantly, it proposes a symmetrical synchronous power transition design, where the power of the boosting and deboosting tubes changes synchronously according to a linear law at the switching moment, and the sum of the power of the two tubes, PA(t) + PB(t) = Pbase + Pwork, remains constant, transforming the total power stability problem into a problem of complementary power between the two tubes. A linear slope limit of dP / dt ≤ 100 MW / s is used to ensure a transition time of 3-5 seconds, with the expected total power fluctuation during switching being less than 0.5%. This design achieves an effective unification of thermal load balance and power stability.

[0104] Heat load calculation and normalization dynamic adjustment mechanism based on temperature weighting function: This invention incorporates temperature factors into heat load calculation and defines cumulative heat load. The temperature weighting function An exponential form is used to better reflect the nonlinear acceleration effect of high-temperature damage, while existing technologies typically only consider power integrals and neglect the temperature effect. This paper proposes for the first time a normalized dynamic adjustment mechanism based on the relative deviation of the heat load. Calculate adjustment amount : Then, normalization is performed to adjust the operating power of the gyrotron to be adjusted. for: This ensures that the sum of the adjustments is zero, maintaining a constant total power. This mechanism allows the heat load deviation to converge from 20-30% to within 5% within 2-3 operating cycles, and the algorithm complexity of O(N) supports linear expansion.

[0105] The core differences between this invention and existing technologies lie in three aspects:

[0106] First, a shift in operating philosophy: Existing technologies employ discrete state switching (abrupt transitions between standby and operation or between shutdown and operation), while this invention employs continuous state regulation (smooth transition between base power and operating power, always maintaining hot standby), reducing the delay and impact of state switching.

[0107] Second, the innovation of heat load management strategy: existing technologies adopt static allocation (constant power operation) or coarse rotation (start-stop intermittent), while the present invention adopts fine rotation plus dynamic balancing (power level rotation plus closed-loop feedback adjustment), which achieves heat load balancing and maintains total power stability.

[0108] Third, the collaborative design concept: existing technologies focus on local optimization for single problems, while this invention considers the three major objectives of rapid response, balanced heat load, and stable power at the system level. Low-power basic operation and time-sharing heat load management support and promote each other, striving to balance the contradictions between various performance indicators and achieve multi-objective optimization.

[0109] Example 2

[0110] This embodiment uses a 4-tube 170 GHz ECRH system to illustrate the heat load management method of the multi-tube ECRH system based on low-power operation in Embodiment 1:

[0111] In this embodiment, the multi-tube ECRH system includes four gyrotubes. , , , Each gyrotron operates at a frequency of 170 GHz, with a rated power of 0.8 MW to 1.0 MW per tube, and an adjustable power range of 0.2 MW to 1.0 MW. See also... Figure 2 Each gyrotube is equipped with a single-tube controller. Equipped with a single-tube controller gyro Equipped with a single-tube controller gyro Equipped with a single-tube controller gyro Equipped with a single-tube controller Each single-tube controller includes a microcontroller, specifically an ARM Cortex-M7 microcontroller with a clock frequency of 200 MHz. Each controller also includes a PI power control module, a temperature monitoring module, a power measurement module, a safety protection module, and a CAN communication module, all connected to the microcontroller. The design control cycle is 10 milliseconds. The PI power control module adjusts the operating power of the gyrotron, the temperature monitoring module collects the gyrotron's temperature, the power measurement module collects the gyrotron's operating power, and the CAN communication module connects to the CAN bus to transmit the collected temperature and power data to the central dispatch controller. The central dispatch controller uses an industrial computer running the Linux-RT real-time operating system, with a design control cycle of 50 milliseconds. It includes four main functional modules: rotation scheduling, power coordination, thermal load balancing, and data management. The communication network uses a star topology CAN bus with a baud rate of 1 Mbps and a time synchronization accuracy of less than 1 millisecond.

[0112] Step 1: After the multi-tube ECRH system is powered on, the central dispatch controller loads the configuration parameters. In this embodiment, the configuration parameters are shown in Table 1. The central dispatch controller establishes a connection with the single-tube controller. to CAN communication, detecting 4 gyrotrons , , , The state is synchronized with the system clock. The gyrotrons are started sequentially. , , , With a base power of 0.2MW, and a 10-second start-up interval between adjacent gyrotrons, a staggered start-up strategy is employed to sequentially start the four gyrotrons, thus avoiding power surges. (Gyrotrons...) For example, the cathode preheating power is 10kW, the preheating time is 60 seconds, and the cathode temperature is designed to rise to approximately 1400K. The anode voltage is gradually increased from 0 to 20kV, and the beam current is 0.5A. The cathode voltage is adjusted through a PI power control module to stabilize the output power of the gyrotron at 0.2MW. At this point, the collector temperature is approximately 150℃, and the output window temperature is 100℃. Gyrotron , , , After startup, the system enters hot standby mode, with all four rotary tubes... , , , Operating continuously at a base power of 0.2MW, with a total system power of 0.8MW, the cathode temperature of each cyclotron is maintained at 1400K-1500K to preserve electron emission capability. The collector and output window are expected to be in thermal equilibrium. The PI power control module is operational, with a power tracking accuracy designed to be ±2%. In this state, the multi-tube ECRH system awaits a plasma activation signal, which may last from several minutes to several hours. No manual intervention is required, and a rapid response is possible at any time.

[0113] Table 1. Parameter Configuration of Multi-Pipe ECRH System

[0114]

[0115] Step 2: When a plasma heating request is received, the plasma heating request includes the target total power and operating time required for plasma heating. The target total power is the target total power in Table 1. The runtime is the total runtime in Table 1. In this implementation, the target total power The capacity is 2.0MW, and the runtime is 1000 seconds. The central dispatch controller initiates the time-sharing scheduling algorithm. The algorithm first determines the time period, specifically based on the runtime and time window. for:

[0116]

[0117] in, This represents the floor function, which rounds down to the nearest integer, where the given value is the largest integer not greater than or equal to the given value. . For runtime, For time windows.

[0118] In this embodiment, runtime The time window is 1000 seconds. The duration is 250 seconds, therefore the time period The value can be 0, 1, 2, or 3, which correspond to four time windows. Corresponding to the first time period , Corresponding to the second period , Corresponding to the third time period , Corresponding to the fourth period Throughout all time periods, one cyclotron is rotated as the resting cyclotron, while the remaining cyclotrons operate continuously at base power, and the operating cyclotrons operate continuously at working power. This cyclical rotation ensures that all four cyclotrons rest in turn. (The last sentence appears to be a repetition and can be omitted.) for:

[0119]

[0120] in, For time period, The number of rotary tubes, Modulo operation.

[0121] In this embodiment, the first time period Inside, rotary tube Continuous operation at base power, gyrotron , , Continuous operation at operating power; second period Inside, rotary tube Continuous operation at base power, gyrotron , , Continuous operation at operating power; third period Inside, rotary tube Continuous operation at base power, gyrotron , , Continuous operation at operating power; fourth period Inside, rotary tube Continuous operation at base power, gyrotron , , Continuous operation at working power. Resting tube power. Power of the working tube Verify the total power constraint, total power .

[0122] Each time period includes a power regulation phase and a steady-state operation phase. During the power regulation phase of the first time period, the gyrotube... Maintain base power, gyro , , The power is increased from the base power to the operating power at the rate of power change. During the steady-state operation phase of the first period, the gyro... Continuous operation at base power, gyrotron , , It operates continuously at its operating power; during the power regulation phase of the second period, the gyrotube... To transform the resting tube into a working tube, a rotary tube. To change from a working tube to a resting tube, a rotary tube. The gyrotube increases from base power to operating power at a rate of power change. The gyrotube decreases from operating power to base power at a rate of power change. , During the steady-state operation phase of the second time period, the gyrotube operates continuously at its operating power. Continuous operation at base power, gyrotron , , It operates continuously at its operating power; during the power regulation phase of the third period, the gyrotube... To transform the resting tube into a working tube, a rotary tube. To change from a working tube to a resting tube, a rotary tube. The gyrotube increases from base power to operating power at a rate of power change. The gyrotube decreases from operating power to base power at a rate of power change. , Operating continuously at working power, during the steady-state operation phase of the third time period, the gyro... Continuous operation at base power, gyrotron , , It operates continuously at its operating power; during the power regulation phase of the fourth period, the gyrotube... To transform the resting tube into a working tube, a rotary tube. To change from a working tube to a resting tube, a rotary tube. The gyrotube increases from base power to operating power at a rate of power change. The gyrotube decreases from operating power to base power at a rate of power change. , Operating continuously at working power, during the steady-state operation phase of the fourth time period, the gyro... Continuous operation at base power, gyrotron , , It operates continuously at its operating power.

[0123] See Figure 3 and Figure 4 , Figure 3 This diagram illustrates the power distribution timing of a 4-tube system over a 1000-second operating cycle. Each line represents the power status of one cyclotron. The operating range is 0.6 MW, and the rest range is 0.2 MW. The operating cycle is divided into four 250-second time windows, with each tube sequentially entering the rest state: Cyclotron 1 rests in time window 1, Cyclotron 2 rests in time window 2, Cyclotron 3 rests in time window 3, and Cyclotron 4 rests in time window 4. The total system power remains constant at 2.0 MW. The rest range uses low-power baseline operation (0.2 MW instead of shutdown) to ensure rapid switching and thermal recovery. Figure 4 This demonstrates the smooth power transition at the time-switching point (t=250 seconds). Gyroscope 1 (solid line) linearly increases from the rest position (0.2 MW) to the operating position (0.6 MW), gyroscope 2 (dashed line) linearly decreases from the operating position to the rest position, while gyroscopes 3 and 4 remain at their operating positions. The power change is limited by a linear slope (100 MW / s), with a transition time of 4 seconds. The sum of the power outputs of gyroscopes 1 and 2 remains constant at 0.8 MW, ensuring a stable total system power of 2.0 MW throughout the transition.

[0124] The following is a detailed description of the operation of the four rotary tubes during the four time periods:

[0125] During the first period (0-250 seconds): at t=0, the heating command is received, the period is determined to be n=0, and the resting tube is identified as a rotary tube. Power distribution is gyro Maintain 0.2 MW, gyrotube Rotary tube Rotary tube The power output increased from 0.2 MW to 0.6 MW. The power regulation process used a linear slope dP / dt = 100 MW / s, with a regulation time of 4 seconds. The power evolution was Pi(t) = 0.2 + 0.1×t (t in seconds, 0 ≤ t ≤ 4). The total power was designed to linearly increase from 0.8 MW to 2.0 MW. During the steady-state operation phase (4-250 seconds), the gyrotron... Sustained operation at 0.2 MW, with the collector temperature designed to be maintained at 150℃-180℃ for thermal recovery; gyrotube Rotary tube Rotary tube The system operates at a sustained power of 0.6 MW, with the collector temperature rising to 320℃-350℃ to handle the main heating. The total system power remains stable at 2.0 MW, with fluctuations less than ±20 kW (less than 1%). The system collects and stores power, temperature, cumulative energy, and cumulative heat load data for each rotary tube every second.

[0126] The second time period, from 250 to 500 seconds, involves switching and operation: The switching occurs during the 250-second time period (t=250 seconds), with time period determination n=1, and the rest tube is switched to a rotary tube. Power distribution is gyro From 0.2 MW to 0.6 MW, cyclotron From 0.6 MW to 0.2 MW, cyclotron Rotary tube Maintain 0.6 MW. To avoid power step jumps, a symmetrical synchronous power transition design is adopted.

[0127] During the transition period of 250-254 seconds, the rotary tube Power P1(t') = 0.2 + 0.1×t' increases linearly (t'=t-250, 0≤t'≤4), gyrotube The power P2(t') = 0.6 - 0.1×t' decreases linearly, and the sum of the power of the two tubes, P1(t') + P2(t') = 0.8 MW, remains constant, plus the power of the gyrotube. Rotary tube The initial power output is 1.2 MW, with a constant total power output of 2.0 MW. Single-tube controller. and The PI controller synchronously performs power point tracking, updating the target power every 10 milliseconds. Simulated power tracking of the target power achieves a tracking accuracy of ±2%. After the transition is complete, it runs in steady state for 500 seconds, then the gyrotron... Upon entering working condition, the collecting electrode temperature rises from 170℃ to 340℃, and the gyrotube... Entering resting state, the collecting electrode temperature drops from 350℃ to 180℃, and the gyrotube... Rotary tube Maintaining operational status, the total power is stabilized at 2.0 MW, with power fluctuations during the transition period designed to be less than ±10 kW (less than 0.5%).

[0128] The third time slot (500-750 seconds) and the fourth time slot (750-1000 seconds) alternate according to the same rules, with the rotary tube... and gyro The tubes sequentially enter the rest mode. After a complete 1000-second cycle, each rotary tube has undergone 750 seconds of operation (3 periods × 250 seconds, power 0.6 MW) and 250 seconds of rest mode operation (1 period × 250 seconds, power 0.2 MW), with the designed cumulative output energy... =750×0.6 + 250×0.2 = 500 MJ, total system output energy = 4 × 500 = 2000 MJ, equivalent to 2 MW × 1000 seconds. Each rotary tube experiences the same operating mode, achieving a balanced distribution of heat load.

[0129] Step 3: During the rotation scheduling process, the central dispatch controller synchronously executes heat load balancing control. Step 3 specifically includes the following steps:

[0130] Step 3.1: Each individual tube controller periodically collects the operating power of each gyrotron. and collection temperature The data is transmitted to the central control unit via the CAN bus. The central control unit then calculates the cumulative heat load of each rotary tube. for:

[0131]

[0132] in, For a moment The first collection The operating power of each gyrotube The data acquisition period is 5 seconds in this embodiment. The total number of data collections within a time window. For a moment The first collection Temperature of the gyrotube The corresponding temperature weighting function, , For reference temperature, For parameters, in this embodiment, the parameters are... It is 1.8, reference temperature The temperature is 300℃. The temperature weighting function reflects the nonlinear acceleration effect of high-temperature damage. For example, when T=150℃, f(150)≈0.41, and when T=350℃, f(350)≈1.35. Under the same power, the contribution of operating at 350℃ to the heat load is 35% higher than that of operating at 300℃.

[0133] Step 3.2: At the end of each time window, in this embodiment the time points corresponding to the end of the time window are 250 seconds, 500 seconds, and 750 seconds, the central dispatch controller performs deviation evaluation.

[0134] Step 3.2.1: Calculate the average heat load of all rotary tubes. :

[0135]

[0136] in, For the first The cumulative heat load of each rotary tube at the end of the current time window The number of rotary tubes;

[0137] Step 3.2.2, calculate the first... Relative deviation of heat load of each rotary tube :

[0138]

[0139] Rotary gyroscopes with a relative heat load deviation exceeding a threshold are marked as gyroscopes requiring adjustment; in this embodiment, the threshold is 10%. For example, assuming t=500 seconds... =292 MJ, =220 MJ, =298 MJ, =302 MJ, calculated to =278MJ, gyrotube deviation =+5%, Rotary tube deviation =-21%, gyrotube deviation =+7%, Rotary tube deviation =+9%. Rotary tube The deviation of -21% exceeds the threshold, triggering dynamic adjustment.

[0140] Step 3.3: Calculate the adjustment amount based on the relative deviation of the heat load of the rotary tube to be adjusted. Based on adjustment amount Adjust the operating power of the gyrotube to be adjusted. .

[0141] Step 3.3.1: Calculate the adjustment amount based on the relative deviation of the heat load of the rotary tube to be adjusted. :

[0142]

[0143] in, For the rotary tube to be adjusted The relative deviation of heat load, , This refers to the gain coefficient, specifically the gain coefficient in this embodiment. It is 0.8. This refers to the operating power; following the example in step 3.2, for a gyrotube... , .

[0144] Step 3.3.2: If the gyro tube to be adjusted is the working tube within the current time window, adjust the operating power of the gyro tube to be adjusted. for: If the gyro tube to be adjusted is in a resting state within the current time window, adjust the operating power of the gyro tube to be adjusted. for: ; For resting power. For example, in the third time period, the cyclone... In working condition (gyrotube) (Rest), adjusted power is gyrotube 0.6 MW, gyrotron The gyrotube is 0.6 + 0.101 = 0.701 MW. 0.2 MW (rest), rotary tube It is 0.6 MW.

[0145] Step 3.4: To maintain a constant total power, the operating power of all working tubes is dynamically adjusted according to the time period.

[0146] Step 3.4.1: Calculate the total adjustment amount using normalization. ,

[0147] Step 3.4.2: The number of working tubes is 3. Calculate the compensation amount. for:

[0148]

[0149] Step 3.4.3: Final adjustment to rotary tube It is 0.566 MW, gyrotron It is 0.667 MW, gyrotron 0.2 MW, gyrotube It is 0.566 MW.

[0150] Step 3.4.4: Since 0.667MW exceeds the upper limit of the operating power of 0.65MW, the gyrotron is subjected to limiting treatment. 0.65MW, gyrotron and gyro After dividing the remaining power equally, each becomes 0.575 MW, maintaining a total power of 2.0 MW. Through dynamic adjustment, the gyrotron... In the third period, higher power distribution is obtained, accelerating the accumulation of heat load and gradually approaching the average value.

[0151] Convergence verification: Define system heat load deviation for:

[0152]

[0153] in, For the first The relative deviation of the heat load of each rotary tube It is a statistical measure of the overall deviation of the system.

[0154] Under the dynamic adjustment mechanism It decays exponentially over time. Theoretical convergence rate constant Approximately 0.001 Theoretical convergence time constant Approximately 1000 seconds. Theoretical analysis shows that the heat load deviation in the first cycle (0-1000 seconds) is... The heat load deviation decreased from 25% to 15% during the second cycle (1000-2000 seconds). The heat load deviation decreased from 15% to 8% during the third cycle (2000-3000 seconds). The deviation decreased from 8% to 5%. According to theoretical analysis, after 2-3 complete operating cycles, the system heat load deviation converged from the initial 20-30% to within 5%, indicating that the equilibrium control is feasible.

[0155] Working principle: This invention is based on the synergistic effect of two core mechanisms: low-power base operation and time-sharing heat load management.

[0156] The working principle of low-power base operation: Low-power base operation maintains the thermal state of key components by keeping the gyrotron running continuously at 0.2 MW, significantly altering the system's response characteristics. The gyrotron requires a complete preheating process from cold start-up to operating state, and heating the cathode from room temperature to 1800-2000 K consumes a significant amount of energy and time. A base power of 0.2 MW corresponds to a cathode heating power of approximately 8-10 kW, keeping the cathode temperature designed to be maintained at 1400-1500 K, above the electron emission threshold of 1200 K but below the rated operating temperature, in a "warm" state where the electron gun can operate stably at any time. The collector temperature at 0.2 MW power is approximately 150-180℃, which is 45% of the rated operating temperature of 350-400℃, indicating that thermal equilibrium has been reached and the temperature distribution is uniform. This thermal state is expected to allow the gyrotube to be adjusted from 0.2 MW to 0.6-0.8 MW with only minor adjustments to the cathode voltage or anode current, without having to go through the complete startup process of cathode preheating, component thermal expansion and contraction, and space charge establishment, reducing the response time from 30-60 seconds to less than 5 seconds.

[0157] The reduction in thermal shock stems from the decrease in the temperature gradient. Thermal stress σth is proportional to the temperature gradient ΔT. In conventional mode, the collector electrode is instantly heated from room temperature (20°C) to 350°C, resulting in a ΔT of 330 K and generating enormous thermal stress. In low-power baseline operation mode, the collector electrode is heated from 150°C to 350°C, with a ΔT of only 200 K, and the thermal stress is expected to decrease by approximately 40%. More importantly, the initial temperature distribution is already relatively uniform, and the temperature gradient is smaller, further reducing local stress concentration. A large power regulation margin (0.6 MW per tube, 2.4 MW for a 4-tube system) provides fault tolerance and flexibility. When the power of one tube fluctuates or fails, other tubes can quickly compensate, and the heating power can be adjusted in real time according to changes in plasma state without starting or stopping the gyrotubes.

[0158] The working principle of time-of-use heat load management: The core of time-of-use heat load management is to ensure that each pipe experiences the same operating mode through periodic rotation. Ideally, N Total root canal operation time Divided into N A time window, each window One rotary tube rests in each window (power is the resting power). N-1 root canal operation (power is operating power) ).

[0159] For gyrotube i, the working time for:

[0160]

[0161] rest time Cumulative heat load (ignoring temperature differences) for:

[0162]

[0163] This formula applies to all gyrotubes. The same, achieving complete equilibrium. In actual operation, due to temperature differences (higher temperature during operation, lower temperature during rest), the accumulated heat load... There will be deviations, but they can be further optimized through dynamic adjustments.

[0164] Total power stability is achieved through clever power allocation. At any given moment, the system's total power... The operating power is determined by the total power constraint. Substituting, we get:

[0165]

[0166] Total power remains constant. A symmetrical synchronous design is used during switching to maintain stable total power. Assume gyrotube A transitions from rest to operation, and gyrotube B transitions from operation to rest. During the transition period… Linear increase, The slope is linear. Indicates the duration of the transition period. The power decreases linearly, and the sum of the power of the two transistors is:

[0167]

[0168] The sum of the power of the two tubes is constant, and the power of the other tubes remains unchanged, so the total power Ptotal is constant.

[0169] Thermal recovery depends on the cooling process following power reduction. The evolution of the collector temperature follows a first-order differential equation:

[0170]

[0171] in, For heat capacity, Input thermal power (proportional to the power of the gyrotron) This represents the cooling power (proportional to temperature). In steady state... .have to:

[0172]

[0173] in, To collect the extremely steady-state temperature, This refers to the cooling water temperature (typically 20-30℃). The equivalent heat transfer coefficient, expressed in W / (m²·K), reflects the heat dissipation capacity of the cooling system.

[0174] From operating power Reduced to resting power At that time, the temperature from Down to Among them, temperature and temperature They are respectively:

[0175]

[0176]

[0177] in, The power-to-heat conversion efficiency (or thermal coupling coefficient) represents the proportion of the output power of the gyrotron that is converted into the heat load of the collector electrode. A typical value is 0.3-0.5 (i.e., 30%-50% of the microwave power is lost at the collector electrode).

[0178] Temperature drop for:

[0179]

[0180] Regarding the parameters of this invention: =0.6 MW, =0.2 MW, ΔT approximately 170℃. After approximately 250 seconds (approximately one thermal time constant) (seconds), the collecting electrode temperature is expected to drop from about 350°C to about 180°C, effectively mitigating heat accumulation.

[0181] The working principle of dynamic adjustment: Heat load deviation stems from non-ideal factors in actual operation. Differences of ±5-10% in cooling water flow rate, pipe resistance, and heat exchanger efficiency across pipes lead to varying cooling efficiencies. Inconsistent preheating temperatures and start-up times across pipes result in differences in initial conditions. Power measurement accuracy is ±1-2%, accumulating over time. Batch variations exist in the thermal conductivity and heat capacity of the collector electrode material. These factors cause cumulative heat load deviations even under the same operating mode.

[0182] Dynamic adjustment employs proportional feedback control, based on heat load deviation. Calculate adjustment amount The gain coefficient k is set to 0.8. Physically, this means the heat load is too high. When the power is reduced, heat accumulation is slowed down, and the heat load is lower. Increasing power accelerates heat accumulation. The deviation evolves over time as follows: , The solution is a constant. The exponential decay eventually approaches zero. To maintain a constant total power, the sum of the adjustments must be zero. Normalization is applied, and the adjusted operating power of the gyrotron is then calculated. for:

[0183]

[0184] in, Based on adjustment amount The operating power of the gyrotron to be adjusted If the gyrotube to be adjusted is in operation within the current time window, the adjusted operating power will be used accordingly. If the gyro tube to be adjusted is in rest mode within the current time window, . This indicates the number of work tubes within the current time window. As a compensation term, the compensation term is evenly distributed among all working tubes, which will reduce the power of the working tubes operating at their operating power. Adjusted to The resting tube maintains its base power. Since only the operating tube is involved in the adjustment, the total power is verified. for:

[0185]

[0186] It achieves both heat load compensation and ensures that the total power remains unchanged.

[0187] Compared with the prior art, the present invention has the following beneficial effects:

[0188] First, it significantly reduces cold start delay and improves response speed. This invention maintains key components of the gyrotron at a constant temperature through low-power operation, with the cathode temperature designed to be maintained at 1400-1500 K above the electron emission threshold, and the collector and output window expected to be in thermal equilibrium. Theoretical analysis suggests that the power regulation response time can be shortened from the traditional 30-60 seconds to approximately 5 seconds, representing an expected improvement in response speed of over 80%. Theoretical analysis indicates that the design response time for adjusting from 0.2 MW to 0.6 MW is approximately 4 seconds, and the design response time for adjusting from 0.2 MW to 0.8 MW is approximately 5 seconds, while the traditional cold start to 0.8 MW requires approximately 45-60 seconds. This rapid response capability is expected to meet the requirements of modern tokamak device plasma control systems for rapid auxiliary heating response. Simultaneously, this invention reduces the maximum power surge amplitude from 0-0.8 MW to 0.2-0.8 MW, a reduction of 25%, and the collector temperature gradient from 330 K to 200 K, with an expected reduction in thermal stress of approximately 40%.

[0189] Second, it achieves balanced heat load and improves system stability. This invention uses time-sharing scheduling to ensure each tube experiences the same operating mode: 750 seconds of operation and 250 seconds of rest per tube. This periodic thermal recovery reduces the expected collector temperature from approximately 350°C to approximately 180°C. This is combined with a temperature weighting function. By calculating the cumulative heat load and implementing a dynamic adjustment mechanism, the cumulative heat load deviation of each tube is reduced from 30-40% in constant power operation to less than 10%, and can be further optimized to less than 5% after 2-3 operating cycles. Simulation analysis of a 4-tube system over 1000 seconds shows that the heat load deviation in constant power mode can reach 35-40%, causing the peak temperature of some tubes to approach the 400℃ limit at approximately 395℃. The heat load deviation of this invention is expected to be approximately 9%, and the peak temperature is expected to be approximately 350℃, with a safety margin of approximately 12%. Heat load balancing allows the system to better utilize the capacity of all cyclotron tubes, and the continuous operation capability is expected to increase from 600-800 seconds to over 1000 seconds, an expected improvement of approximately 40%. The overall system efficiency is expected to be about 25-30% higher than that of constant power mode.

[0190] Third, maintaining stable total power is expected to meet plasma control requirements. This invention achieves high stability of total power through a triple guarantee mechanism: the operating power is strictly determined by the total power constraint. Theoretically, this design ensures a constant total power at any given time. A symmetrical synchronous power transition design is used during switching, maintaining a constant sum of power from the boost and deboost transistors, with a transition time of 4 seconds. Dynamic adjustments employ normalization to ensure the total adjustment sum is zero. The expected standard deviation of the total power during a 1000-second simulation is approximately 12 kW, with a relative fluctuation of approximately 0.6%. The maximum deviation during the switching transition is expected to be approximately 8 kW (approximately 0.4%), better than the ±5% requirement of the plasma control system. Based on theoretical model analysis, the expected electron temperature fluctuation of plasma parameters is less than 3%, which is expected to avoid rupture events caused by power fluctuations. Compared to the ±20% power fluctuation of intermittent operation and the ±2% of constant power operation, this invention controls the total power fluctuation within ±1%, achieving a good balance between thermal load management and power stability in its design, providing a theoretical basis for stable plasma control and long-pulse high-parameter discharge.

[0191] Example 3

[0192] See Figure 5 This embodiment provides a heat load management system for a multi-pipe ECRH system operating on a low-power basis. The system includes:

[0193] The initialization module is used to sequentially start the gyrotrons in the multi-tube ECRH system to base power, and each gyrotron continues to operate at base power.

[0194] The time-sharing scheduling module is used to determine the time period based on the running time and time window when it receives the target total power and running time required for plasma heating. During all time periods, one cyclotron is scheduled as the rest tube and the rest tubes are the working tubes. The rest tube runs continuously at the base power and the working tubes run continuously at the working power. During the transition period between adjacent time periods, the power change rate of the rest tube from the base power to the working power is the same as the power change rate of the working tube from the working power to the base power.

[0195] Among them, the time period is determined based on the runtime and time window. for:

[0196]

[0197] in, This indicates the floor function. For runtime, For time windows.

[0198] Rotate one rotary tube as the resting tube in all time periods. for:

[0199]

[0200] in, For time period, The number of rotary tubes, Modulo operation.

[0201] Each gyrotube is from the first gyrotube to the second gyrotube. Rotary tube, all time periods including the first time period in sequence To the Time period Each time period includes a power regulation phase and a steady-state operation phase. During the power regulation phase of the first time period, the first gyrotron maintains its base power, while the second gyrotron and the third gyrotron maintain their base power. The gyrotron increases from base power to operating power at a rate of power change. During the steady-state operation phase of the first time period, the first gyrotron operates continuously at base power, while the second gyrotron... The gyrotubes operate continuously at their operating power; during the power adjustment phase of the second time period, the first gyrotube increases from its base power to its operating power at a rate of power change, the second gyrotube decreases from its operating power to its base power at a rate of power change, and the third gyrotube... The gyrotron operates continuously at its operating power. During the steady-state operation phase of the second time period, the second gyrotron operates continuously at its base power, while the first, third, and subsequent gyrotrons operate continuously at their base power. The gyrotron operates continuously at its working power; and so on, in the... During the power regulation phase of the time period, the first The gyrotron increases from base power to operating power at a rate of power change. The gyrotron decreases from its operating power to its base power at a rate of power change, from the first gyrotron to the second. The gyrotron operates continuously at its working power, in the first... During the steady-state operation phase of the time period, the first The gyrotron operates continuously at base power, from the first gyrotron to the second. The gyrotube operates continuously at its working power.

[0202] The heat load balancing control module is used to periodically collect the operating power and collector temperature of each gyroscope, calculate the cumulative heat load of each gyroscope, and at the end of each time window, calculate the relative heat load deviation of each gyroscope based on the average heat load of all gyroscopes. Gyroscopes with a relative heat load deviation exceeding a threshold are marked as gyroscopes to be adjusted. The adjustment amount is calculated based on the relative heat load deviation of the gyroscopes to be adjusted, and the operating power of the gyroscopes to be adjusted is adjusted based on the adjustment amount. The operating power of all working tubes is dynamically adjusted according to the time period to keep the target total power constant.

[0203] Among them, the cumulative heat load of each rotary tube for:

[0204]

[0205] in, For a moment The first collection The operating power of each gyrotube The collection period, The total number of data collections within a time window. For a moment The first collection Temperature of the gyrotube The corresponding temperature weighting function, , For reference temperature, For parameters.

[0206] The process of calculating the relative deviation of the heat load of each gyro tube based on the average heat load of all gyro tubes includes:

[0207] Calculate the average heat load of all rotary tubes. :

[0208]

[0209] in, For the first The cumulative heat load of each rotary tube at the end of the current time window The number of rotary tubes;

[0210] Calculate the first Relative deviation of heat load of each rotary tube :

[0211]

[0212] The process of calculating the adjustment amount based on the relative deviation of the heat load of the rotary tube to be adjusted, and adjusting the operating power of the rotary tube based on the adjustment amount, includes:

[0213] The adjustment amount is calculated based on the relative deviation of the heat load of the rotary tube to be adjusted. :

[0214]

[0215] in, For the rotary tube to be adjusted The relative deviation of heat load, , This is the gain coefficient. Operating power;

[0216] If the gyro tube to be adjusted is the working tube within the current time window, adjust the operating power of the gyro tube to be adjusted. for: If the gyro tube to be adjusted is in a resting state within the current time window, adjust the operating power of the gyro tube to be adjusted. for: ; Based on base power.

[0217] The process of dynamically adjusting the operating power of all working tubes according to the time period includes:

[0218] Calculate the total adjustment amount :

[0219]

[0220] in, For the rotary tube to be adjusted The adjustment amount, The number of rotary tubes to be adjusted;

[0221] Based on the total adjustment amount Calculate the compensation amount based on the number of working pipes. for: , The number of rotary tubes;

[0222] The operating power of the gyrotube to be adjusted during the current time period. Adjusted to The power of the operating transistor at its operating power. Adjusted to The rest tube maintains its base power unchanged;

[0223] Determine whether the operating power of the adjusted working tube exceeds the upper limit of the operating power. If the working tube exceeds the upper limit of the operating power, it will operate at the upper limit of the operating power. If the working tube does not exceed the upper limit of the operating power, it will share the remaining power equally. The remaining power is the operating power of the adjusted working tube minus the upper limit of the operating power.

[0224] The cumulative heat load of any rotary tube over a period of time. for:

[0225]

[0226] in, The operating time of a gyrotube within one operating cycle. , The rest time for a rotary tube during one operating cycle. Time window .

[0227] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for thermal load management of a multi-tube ECRH system operating on a low-power basis, characterized by: The method comprises: The method comprises: When the target total power required for plasma heating and the operation duration are received, time periods are determined according to the operation duration and a time window, one gyrotron is scheduled as a rest gyrotron and the rest gyrotrons are scheduled as working gyrotrons in all time periods, the rest gyrotron continuously operates at the basic power, the working gyrotrons continuously operate at the working power, and the power change rate of the rest gyrotron from the basic power to the working power is the same as the power change rate of the working gyrotron from the working power to the basic power in a transition period of adjacent time period switching; The process of calculating the relative deviation of the heat load of each gyrotron based on the average heat load of all gyrotrons comprises:

2. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. The process of calculating the adjustment amount according to the relative deviation of the heat load of the gyrotron to be adjusted and adjusting the operation power of the gyrotron to be adjusted based on the adjustment amount comprises: wherein, is a time period, denotes a floor operation, is a running time, is a time window.

3. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. scheduling a gyrotron on duty for a rest gyrotron in all time periods to be: wherein, is a time period, is a number of gyrotrons, is a modulo operation.

4. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. Each gyrotube is from the first gyrotube to the second gyrotube. Rotary tube, The number of gyrotubes, with all time periods including the first time period in sequence. To the Time period , For time period, The time window is defined as follows: each time period includes a power regulation phase and a steady-state operation phase. During the power regulation phase of the first time period, the first gyrotron maintains its base power, while the second gyrotron... The gyrotron increases from base power to operating power at a rate of power change. During the steady-state operation phase of the first time period, the first gyrotron operates continuously at base power, while the second gyrotron... The gyrotubes operate continuously at their operating power; during the power adjustment phase of the second time period, the first gyrotube increases from its base power to its operating power at a rate of power change, the second gyrotube decreases from its operating power to its base power at a rate of power change, and the third gyrotube... The gyrotron operates continuously at its operating power. During the steady-state operation phase of the second time period, the second gyrotron operates continuously at its base power, while the first, third, and subsequent gyrotrons operate continuously at their base power. The gyrotron operates continuously at its working power; and so on, in the... During the power regulation phase of the time period, the first The gyrotron increases from base power to operating power at a rate of power change. The gyrotron decreases from its operating power to its base power at a rate of power change, from the first gyrotron to the second. The gyrotron operates continuously at its working power, in the first... During the steady-state operation phase of the time period, the first The gyrotron operates continuously at base power, from the first gyrotron to the second. The gyrotube operates continuously at its working power.

5. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. Cumulative heat load of each gyrotron Is: wherein, is the time of day, is the number of the acquisition, is the operating power of the cyclotron, is the acquisition period, is the total number of acquisitions within a time window, is the time of day, is the number of the acquisition, is the temperature of the cyclotron, is the corresponding temperature weight function, , is the reference temperature, is the parameter.

6. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. The process of dynamically adjusting the operation power of all working gyrotrons according to the time period comprises: calculating an average thermal load of all gyrotrons : wherein, is the cumulative heat load of the th gyrotron at the end of the current time window, is the number of gyrotrons; Computing relative deviations of thermal loads of a tubes : 。 7. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. The process of dynamically adjusting the operation power of all working gyrotrons according to the time period comprises: The adjustment amount is calculated according to the relative deviation of the heat load of the gyrotron to be adjusted : wherein, is the relative deviation of the thermal load of the gyrotron to be adjusted, is the relative deviation of the thermal load of the gyrotron to be adjusted, , is the number of gyrotrons, is the gain coefficient, is the operating power; if the to-be-adjusted gyrotron is a working gyrotron in the current time window, adjusting the operating power of the to-be-adjusted gyrotron is: ; if the to-be-adjusted gyrotron is a resting gyrotron in the current time window, adjusting the operating power of the to-be-adjusted gyrotron is: ; the resting power is equal to the basic power.

8. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. The process of dynamically adjusting the operation power of all working gyrotrons according to the time period comprises: calculating the sum of the adjustment amounts : wherein, is an adjustment amount of the gyrotron to be adjusted, is the number of gyrotrons to be adjusted; According to the total of the adjustment amounts and the number of working tubes, the compensation amount is calculated is: , is the number of gyro tubes; adjusting the operating power of the working tube in the current period to , the power of the working tube operating at working power to , the rest tube keeps the basic power unchanged; The process of dynamically adjusting the operation power of all working gyrotrons according to the time period comprises:

9. The method of claim 1, wherein the multi-tube ECRH system thermal load management method is operated based on low power basis. The cumulative heat load of any one gyrotron over a length of operation is: wherein, is the working time of a gyrotron for a length of operation, , is the resting time of a gyrotron for a length of operation, is the time window, , is the working power, the resting power is equal to the base power, is the number of gyrotrons.

10. A thermal load management system for a multi-tube ECRH system operating on a low-power basis, characterized in that: The system comprises: The initialization module is configured to sequentially start the gyrotrons in the multi-gyrotron ECRH system to the basic power, and each gyrotron continuously operates at the basic power. The time-sharing rotation scheduling module is configured to, when the target total power required for plasma heating and the operation duration are received, determine time periods according to the operation duration and a time window, schedule one gyrotron as a rest gyrotron and the rest gyrotrons as working gyrotrons in all time periods, and make the rest gyrotron continuously operate at the basic power and the working gyrotrons continuously operate at the working power. The heat load balancing control module is configured to periodically collect the operation power and the collector temperature of each gyrotron, calculate the cumulative heat load of each gyrotron, calculate the relative deviation of the heat load of each gyrotron based on the average heat load of all gyrotrons at the end of each time window, mark the gyrotron with the relative deviation of the heat load exceeding a threshold as a gyrotron to be adjusted, calculate an adjustment amount according to the relative deviation of the heat load of the gyrotron to be adjusted, adjust the operation power of the gyrotron to be adjusted based on the adjustment amount, and dynamically adjust the operation power of all working gyrotrons according to the time period to keep the target total power constant.

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