A composite coil ohmic drive method and system for a copper conductor tokamak

Abstract

The present application discloses a composite coil ohmic driving method for a copper conductor tokamak, belonging to the technical field of tokamak magnetic field control. Based on the magnetic field distribution generated by each shaping field coil and the central solenoid in the vacuum chamber region, a discharge scheme for the shaping field coil for zero-field matching is given with the poloidal magnetic field at the geometric center being zero as the benchmark; an array composed of multiple single turns is used to measure the ring voltage distribution on the vacuum chamber wall during breakdown, and with the principle of the lowest weighted ring voltage, the shaping field coil is used to compensate for the eddy current on the wall, ultimately achieving a zero-field state in the vacuum chamber during the breakdown period; during the plasma current drive, compensation is carried out by measuring the influence of the external coil current and the eddy current on the vacuum chamber wall on the plasma current measurement; combined with the distribution matrix of the coil drive current, the original current distribution is not destroyed when driving the current, and decoupling is achieved through the mutual inductance matrix between different coils, realizing the coordinated control of multiple coils.

Description

Technical Field

[0001] This application relates to the technical field of Tokamak magnetic field control, and specifically relates to a composite coil ohmic drive method and system for a copper conductor Tokamak. Background Technique

[0002] Magnetic confinement fusion is to use a magnetic field to confine high-energy plasma, so that the ions inside it overcome the Coulomb potential energy under the action of high temperature and high pressure and then undergo fusion. It is the most promising method for the peaceful use of thermonuclear fusion energy. Among the various types of magnetic confinement fusion devices, the Tokamak device is the type of device closest to commercial fusion. The Tokamak device is mainly used for obtaining future clean energy. The magnetic field of this device is composed of a toroidal magnetic field and a poloidal magnetic field. The toroidal magnetic field is mainly generated by toroidal field coils, while the poloidal magnetic field is jointly generated by the plasma current in the plasma and the poloidal field coils outside the plasma. The plasma current is the basis for the confinement of Tokamak magnetic confinement fusion plasma. The poloidal field coils are composed of ohmic coils and shaping field coils. The entire discharge process of the Tokamak is as follows: First, by rapidly changing the current in the ohmic coil and the shaping field coil, a very strong toroidal voltage is formed in the vacuum chamber area to break down the working gas, and a plasma is formed through the "avalanche effect". This stage is the plasma breakdown stage. During this stage, not only a very strong toroidal electric field needs to be generated in the vacuum chamber through electromagnetic induction, but also it is necessary to ensure that the area where the plasma exists in the vacuum chamber is in a zero-field state during the "avalanche effect", that is, the poloidal magnetic field is almost zero, so as to greatly reduce the loss of plasma during the "avalanche effect"; then is the plasma current drive stage. During this stage, the plasma current needs to be accurately measured and effectively controlled. When measuring the plasma current, the magnetic field generated by external coils, vacuum chamber wall eddy currents, etc. around it will seriously interfere with the measurement results. Therefore, to accurately measure the current of the conductive gas in the vacuum chamber, the influence caused by the external coil current and the vacuum chamber wall eddy current needs to be effectively deducted. In addition, the plasma current distribution has a crucial impact on the operating state of the device and the macroscopic parameters of the plasma. Therefore, when driving the plasma current, not only the driving ability of the total current needs to be considered, but also the influence of the current drive process on the plasma current distribution needs to be considered, or in other words, it is necessary to try to keep this current distribution unchanged.

[0003] Such as Figure 1As shown in the figure, in a traditional copper conductor tokamak, the ohmic coil consists of a central solenoid coil and multiple coils. The ohmic field coil is in a natural zero-field state, that is, this coil does not generate a poloidal magnetic field in the central region of the vacuum chamber, and the ohmic coil and the shaping field coil are decoupled and can work independently. The ohmic coil is dedicated to driving the plasma current, and the shaping field coil is dedicated to controlling parameters such as the configuration of the plasma. The traditional ohmic coil driving technology has the following disadvantages: First, the number of coils is large, increasing the costs of device design, manufacturing, and installation, and thus bringing about complex coil / lead / cooling / support structures and great maintenance difficulties; Second, there are often position conflicts between the scattered ohmic coils and the shaping field coils, resulting in a very close distance between them, which not only brings problems of electrical insulation between the coils, but also the electromagnetic forces between these coils are huge. For a device with a megaampere plasma current, the electromagnetic forces between them often reach thousands of tons, further deteriorating the implementation of coil support and posing a huge challenge to the safe operation of the coils; Third, due to the increase in the actual number of turns and inductance of the ohmic coil, the control response rate of the coil power supply decreases, the voltage level of the power supply increases, and at the same current, due to the scattered coils providing negative volt-seconds, the driving ability of the plasma current is reduced instead.

[0004] To address the above engineering problems faced by the shaping field coil of the traditional copper conductor tokamak, the HL-3 tokamak device adopts a layout design of a composite coil, that is, only the central solenoid is retained for the ohmic field coil to efficiently drive the plasma current; the shaping field coil needs to perform multiple tasks such as forming a zero field, compensating for eddy currents, and assisting in driving the plasma current. Therefore, this design layout is called a composite coil layout, as Figure 2 shown in the figure. The poloidal field coil of this device consists only of the central solenoid 2 and multiple shaping field coils 3. Among them, the central solenoid 2 is installed at the position closest to the high-field side inside the toroidal field coil 5, which is beneficial to improving the driving ability of the plasma current. The shaping field coils 3 are distributed in the cavity of the toroidal field coil 5 and are very close to the vacuum chamber 4 in structure, having a strong control ability over key parameters such as the configuration and position of the plasma, and also providing a certain degree of plasma driving ability to some extent; the vacuum chamber 4 occupies as much of the remaining space inside the toroidal field coil 5 as possible on the basis of ensuring the coil position to obtain a higher-parameter plasma; the toroidal field coil 5 provides the most important magnetic field for the confinement of the plasma inside the device. The overall number of coils of the tokamak device with a composite coil layout is reduced, making it easier to implement the engineering of the poloidal field coil, and the localization of the magnetic field generated by the poloidal field coil is better, which is more conducive to implementing plasma control, thus making the tokamak device have a compact structure, high operating parameters, and great potential for improving plasma quality.

[0005] In the case of the layout of the composite coil, there are complex situations such as the central solenoid greatly interfering with the formation of the zero field, the eddy current generated by the toroidal voltage on the vacuum chamber wall during plasma breakdown also destroying the zero field, and the strong coupling state between the central solenoid and the shaping field coils. Therefore, conventional control techniques are not applicable to the collaborative control scenario of such composite coils. Therefore, it is urgent to study a collaborative control applicable to such composite coils to quickly and effectively achieve the ohmic drive of the composite coil on the copper conductor tokamak device. Summary of the Invention

[0006] For the plasma control on the copper conductor tokamak with a composite coil layout, there are difficult problems such as the need for each poloidal field coil (composed of a central solenoid and multiple shaping field coils) to generate a zero field collaboratively during the discharge breakdown stage, accurately measuring the plasma current during plasma current drive, decoupling the strongly coupled poloidal field coils and driving the plasma current collaboratively, and maintaining the current distribution of the conductive gas in the vacuum chamber unchanged. This application proposes a method and system for ohmic drive of the composite coil of a copper conductor tokamak. Based on the magnetic field distribution generated by each shaping field coil and the central solenoid in the vacuum chamber region, a discharge scheme for the shaping field coil with a zero field is given with the poloidal magnetic field at the geometric center being zero as the benchmark; an array composed of multiple single turns is used to measure the toroidal voltage distribution on the vacuum chamber wall during breakdown, and with the principle of the lowest weighted toroidal voltage, the shaping field coil is used to compensate for the eddy current on the wall, ultimately achieving a zero field state in the vacuum chamber during the breakdown period; during plasma current drive, this application measures the influence of the composite coil current and the eddy current on the vacuum chamber wall on the plasma current measurement, and after deducting the above factors, an accurate value of the plasma current is obtained; based on the distribution of the plasma current, a distribution matrix of the driving current of the poloidal field coil is constructed to ensure that the original current distribution is not destroyed when driving the current, and decoupling is achieved through the mutual inductance matrix between different poloidal field coils, realizing effective control of the poloidal field coil and further driving the plasma current.

[0007] This application is realized through the following technical solutions:

[0008] A method for ohmic drive of a composite coil of a copper conductor tokamak, comprising:

[0009] According to the pre-configured current ratio of each shaping field coil and the central solenoid, the central solenoid and each shaping field coil are collaboratively controlled to ensure that the vacuum chamber is in a zero field state during plasma breakdown;

[0010] During plasma current drive, a plasma current measurement signal is obtained in real time, and the plasma current measurement signal is compensated by using the toroidal field coil current, the shaping field coil current, and the vacuum chamber eddy current to obtain a true plasma current signal;

[0011] Based on the deviation value between the true plasma current signal and the desired plasma current signal, the total feedback control amount of the toroidal voltage required for the plasma region is obtained through feedback control based on the deviation value, and in combination with the distribution matrix and the decoupling matrix, the feedback control amounts of the central solenoid and each shaping field coil are determined;

[0012] Based on the desired plasma current signal, the total feedforward control amount of the toroidal voltage required for the plasma region is calculated, and in combination with the distribution matrix and the decoupling matrix, the feedforward control amounts of the central solenoid and each shaping field coil are determined;

[0013] The feedback control amounts of the central solenoid and each shaping field coil are linearly superimposed with their corresponding feedforward control amounts to obtain the control amounts of the central solenoid and each shaping field coil, and based on this, the central solenoid and each shaping field coil are coordinately controlled to achieve stable driving of the plasma current;

[0014] Wherein, the distribution matrix is used to ensure that the distribution of the plasma current does not change when realizing the coordinated control of the central solenoid and each shaping field coil; the decoupling matrix contains the decoupling information of the central solenoid and each shaping field coil.

[0015] In a second aspect, the present application proposes a composite coil ohmic drive system for a copper conductor tokamak, including:

[0016] A zero-field module configured to: according to the pre-configured current ratios of the central solenoid and each shaping field coil, coordinately control the central solenoid and each shaping field coil to ensure that the vacuum chamber is in a zero-field state during plasma breakdown;

[0017] A measurement compensation module configured to: during plasma current drive, real-time acquire the plasma current measurement signal, and compensate the plasma current measurement signal by using the toroidal field coil current, the shaping field coil current, and the vacuum chamber eddy current to obtain the true plasma current signal;

[0018] A feedback control module configured to: according to the deviation value between the true plasma current signal and the desired plasma current signal, obtain the total feedback control amount of the toroidal voltage required for the plasma region through feedback control based on the deviation value, and in combination with the distribution matrix and the decoupling matrix, determine the feedback control amounts of the central solenoid and each shaping field coil;

[0019] A feedforward control module configured to: according to the desired plasma current signal, calculate the total feedforward control amount of the toroidal voltage required for the plasma region, and in combination with the distribution matrix and the decoupling matrix, determine the feedforward control amounts of the central solenoid and each shaping field coil;

[0020] And, an execution module configured to linearly superimpose the feedback control amounts of the central solenoid and each shaping field coil with their corresponding feedforward control amounts to obtain the control amounts of the central solenoid and each shaping field coil, and accordingly perform coordinated control on the central solenoid and each shaping field coil to achieve stable driving of the plasma current;

[0021] Wherein, the distribution matrix is used to ensure that the distribution of the plasma current does not change when realizing the coordinated control of the central solenoid and each shaping field coil; the decoupling matrix contains the decoupling information of the central solenoid and each shaping field coil.

[0022] In a third aspect, the present application provides an electronic device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the steps of the above method are implemented.

[0023] A method and system for ohmic driving of a composite coil of a copper conductor tokamak proposed by the present application. The ohmic driving mainly relies on the central solenoid, and at the same time, the shaping field coil can also provide ohmic driving ability to a certain extent. Compared with the traditional method of driving a copper conductor tokamak using an ohmic coil, when an abnormality or failure occurs in a certain coil in the present application, the control weight can be transferred to other coils with ohmic driving ability, and stable driving of the plasma current can still be achieved within a certain time range, leaving enough time for taking soft landing shutdown measures and ensuring the safe operation of the device;

[0024] For the method and system for ohmic driving of a composite coil of a copper conductor tokamak proposed by the present application, the central solenoid and the shaping field coil with ohmic driving ability can all be located inside the toroidal field coil, making the control of the plasma more flexible. Description of the Drawings

[0025] The drawings described herein are used to provide a further understanding of the embodiments of the present application, form a part of the present application, and do not limit the embodiments of the present application. In the drawings:

[0026] Figure 1 It is a schematic diagram of the layout of a traditional plasma current driving coil;

[0027] Figure 2 It is a flowchart of the plasma current driving method according to an embodiment of the present application;

[0028] Figure 3 It is a schematic diagram of the layout of the plasma current driving coil adopted in an embodiment of the present application;

[0029] Figure 4 It is a schematic block diagram of the plasma current driving system according to an embodiment of the present application;

[0030] Figure 5 To achieve the driving effect of a plasma current of 1 MA by using the plasma current driving method proposed in the embodiments of the present application.

[0031] Reference numerals and corresponding component names:

[0032] 1 - Ohmic coil, 2 - central solenoid, 3 - shaping field coil, 4 - vacuum vessel wall, 5 - toroidal field coil, 6 - divertor, 7 - sector adapter. Specific embodiments

[0033] To make the objectives, technical solutions, and advantages of the present application more clearly understood, the present application will be further described in detail below with reference to the embodiments and the accompanying drawings. The illustrative embodiments of the present application and their descriptions are only used to explain the present application and are not intended to limit the present application.

[0034] Embodiment:

[0035] The ohmic field coils on traditional copper - conductor tokamaks generate a natural zero - field in the central region, and this zero - field is largely decoupled from other shaping field coils. Therefore, there is no need to consider the zero - field problem during the breakdown stage. However, in the case of the composite coil layout, the central solenoid will interfere with the formation of the zero - field to a great extent. For this reason, multiple shaping field coils need to work together with the central solenoid to form and maintain the zero - field. At the same time, the currents in each coil change synchronously, which generates a toroidal electric field. When the plasma breaks down, the toroidal voltage reaches dozens of volts. The toroidal voltage can drive eddy currents on the vacuum chamber wall in the order of hundreds of kilo - amperes, which is sufficient to destroy the zero - field. Therefore, the eddy currents on the vacuum chamber wall must be compensated. Even more complex is that although the magnetic field at the vacuum chamber can be regarded as quasi - toroidally symmetric, the poloidal distribution is very asymmetric. This leads to an uneven poloidal distribution of the eddy currents on the vacuum chamber wall. In addition, the eddy currents on the vacuum chamber wall are driven by the toroidal voltage, but the differences in different poloidal positions of the vacuum chamber result in a non - linear time - constant in the above - mentioned current distribution, which poses a great challenge to the measurement and compensation of eddy currents. Moreover, in the composite coil layout, the various shaping field coils and the central solenoid are in a strongly coupled state. The allocation and decoupling control of the functions of each coil are difficult problems faced by the plasma control system of the composite - coil tokamak device. Based on this, this embodiment proposes a composite - coil ohmic driving method for a copper - conductor tokamak. The composite - coil ohmic driving method proposed in this embodiment uses the central solenoid and multiple shaping field coils to jointly achieve plasma current driving, specifically including: First, during the plasma breakdown, based on the magnetic - field distribution generated by each shaping field coil and the central solenoid in the vacuum chamber region, a discharge scheme for the shaping field coils for zero - field matching is given with the poloidal magnetic field at the geometric center being zero as the benchmark. An array composed of multiple single - turns is used to measure the toroidal voltage distribution on the vacuum chamber wall during breakdown. Taking the minimum weighted toroidal voltage as the principle, the shaping field coils are used to compensate the eddy currents on the vacuum chamber wall, and finally, the vacuum chamber is in a zero - field state during breakdown; Then, during the plasma current driving, by using the shaping - field current and the compensation of the measurement signal by the eddy currents on the vacuum chamber wall, an accurate plasma current value is obtained. Based on the accurate plasma current value and the current expected value, after feedback control, the total feedback control amount is obtained. Based on the total feedback control amount and combined with the distribution matrix and the decoupling matrix, the feedback control amounts on the central solenoid and each shaping field coil are obtained. At the same time, according to the current expected value, the total feed - forward control amount is calculated. Based on this total feed - forward control amount and combined with the distribution matrix and the decoupling matrix, the feed - forward control amounts on the central solenoid and each shaping field coil are obtained. Finally, according to the feedback control amounts and the corresponding feed - forward control amounts on the central solenoid and each shaping field coil, the control amounts on the central solenoid and each shaping field coil are determined, and accordingly, the coordinated control of the central solenoid and each shaping field coil is carried out.

[0036] As Figure 3 shown, the plasma current driving method proposed in this embodiment specifically includes the following steps:

[0037] Step 100: According to the pre-configured current ratio of each shaping field coil to the central solenoid, the central solenoid and each shaping field coil are controlled collaboratively to ensure that the vacuum chamber is in a zero-field state during plasma breakdown.

[0038] The breakdown process of the plasma requires that the poloidal magnetic field in the plasma formation region be very small, that is, a zero-field region is formed. Otherwise, the breakdown plasma will be quickly lost, resulting in breakdown failure. Therefore, in the case of the layout of the composite coil, it is necessary to consider how to control the central solenoid and each shaping field coil collaboratively to ensure that the vacuum chamber is in a zero-field state during plasma breakdown.

[0039] An optional implementation manner: Considering the interference of the central solenoid to the zero-field formation and the destruction of the zero-field by eddy currents in the case of the layout of the composite coil, in this embodiment, first, multiple shaping field coils are used to compensate the central solenoid, and then the current waveforms of each shaping field coil are adjusted to compensate the eddy currents, so as to determine the optimal current ratio of the central solenoid and each shaping field coil to achieve a zero-field state in the vacuum chamber during plasma breakdown. The specific process includes:

[0040] Step 101: Based on the magnetic field distribution generated by the central solenoid and each shaping field coil in the vacuum chamber region, an initial shaping field coil discharge scheme for zero-field matching is given with the poloidal magnetic field at the geometric center of the vacuum chamber region being zero as the reference. The specific process is as follows: Use a magnetic probe array to measure the magnetic field distribution when the single-pass central solenoid and each shaping field coil are energized; Based on the Biot-Savart law, use the finite element analysis method to calculate the magnetic field distribution generated by the central solenoid and each shaping field coil; Use the measured magnetic field distribution to verify whether the calculated magnetic field distribution meets the requirements (that is, the magnetic field distribution calculated by the finite element analysis method is consistent with the actual situation or the deviation is within an acceptable range); If so, use the magnetic field distribution of each shaping field coil calculated to compensate the poloidal magnetic field generated by the central solenoid, and configure the ratio (ratio) of the current in each shaping field coil to the current in the central solenoid with the poloidal magnetic field in the geometric center region of the vacuum chamber being zero as the judgment basis to form an initial shaping field coil discharge scheme for zero-field matching;

[0041] Step 102: Measure the toroidal voltage distribution on the vacuum chamber wall during breakdown using an array of multiple single-turn coils. With the principle of minimizing the weighted toroidal voltage, adjust the discharge scheme of the shaping field coils for the initial null field to compensate for the eddy current on the vacuum chamber wall and determine the optimal discharge scheme of the shaping field coils for the null field. The specific process is as follows: First, measure the toroidal voltage in a certain poloidal region of the vacuum chamber during plasma breakdown using a single-turn coil. Calculate the self-inductance of the vacuum chamber wall in this region based on the spatial characteristic information of the single-turn coil. Fit the decay curve of the toroidal voltage after breakdown using an exponential function to obtain the characteristic time of this region, and then obtain the resistance of this region. The poloidal distributions of the inductance and resistance on the vacuum chamber wall can be measured using multiple single-turn coils. Calculate the mutual inductance generated by the shaping field coil on the vacuum chamber wall in its adjacent region based on the spatial dimensions of the shaping field coil. Based on the measured eddy current distribution on the vacuum chamber wall, inversely calculate the poloidal magnetic flux distribution and time evolution curve required to compensate for the eddy current, and thus obtain the current evolution curve in each shaping field coil. Weight the single-turn coils according to the density of the single-turn coils, and the weighting coefficient is the reciprocal of the distance between two adjacent single-turn coils. With the minimum weighted average value of the single-turn coils as the index, adjust the current waveforms of each shaping field coil to obtain the best eddy current compensation effect, and thus determine the optimal discharge scheme of the shaping field coils for the null field (i.e., the ratio of the shaping field coil current to the central solenoid current). In the subsequent actual application process, the determined current ratio of the central solenoid and the shaping field coil can be directly used to control them synergistically to achieve a zero-field state of the vacuum chamber during plasma breakdown.

[0042] Step 200: During plasma current drive, obtain the plasma current measurement signal in real time, and compensate the plasma current measurement signal using the toroidal field coil current, the shaping field coil current, and the vacuum chamber eddy current to obtain the true plasma current signal.

[0043] In the case of the layout of the composite coil, considering that the shaping field coil is arranged inside the toroidal field coil and is very close to the vacuum chamber wall, the eddy current on the vacuum chamber wall will seriously affect the measurement of the plasma current. Therefore, in order to obtain an accurate plasma current value, in this embodiment, the plasma current measurement value is compensated to eliminate the influence of external interference on the measurement.

[0044] Specifically, this step 200 further includes the following sub-steps:

[0045] Step 201: Obtain the plasma current measurement signal in real time. In a tokamak device, the plasma current is usually measured by Rogowski coils. The Rogowski coils are distributed along the toroidal direction of the tokamak device, either inside or outside the vacuum chamber. The two ends of the Rogowski coils are connected to the input end of an integrator. The original signal measured by the Rogowski coils is integrated to obtain the plasma current measurement signal. Connecting the output end of the integrator to a data acquisition card can obtain the plasma current measurement signal. This plasma current measurement signal is the integral value of the toroidal magnetic field along the direction of the Rogowski coils, multiplied by the number of turns of the Rogowski coils, multiplied by the cross-sectional area of the Rogowski coils, and divided by the integration time.

[0046] Step 202: Obtain the toroidal field coil current and the currents of each shaping field coil in real time, and perform a primary compensation on the plasma current measurement signal by combining the toroidal field coil and the influence factors corresponding to each shaping field coil to obtain the compensated plasma current measurement signal.

[0047] This step uses Rogowski coils and an integrator to measure the toroidal field coil current and the currents of each shaping field coil in real time, that is, a circle of Rogowski coils is arranged along the circumferential direction of the toroidal field coil and each shaping field coil. The two ends of the Rogowski coils are connected to the input end of the integrator. The original signal measured by the Rogowski coils is integrated to obtain the corresponding toroidal field coil or shaping field coil current. Its measurement principle is the same as that described in Step 101 above and will not be elaborated here.

[0048] After obtaining the toroidal field coil current and the currents of each shaping field coil in real time, the product of the toroidal field coil current and its influence factor is used as the interference current of the toroidal field coil, and the product of the shaping field coil current and its influence factor is used as the interference current of the shaping field coil. It should be noted that there are multiple shaping field coils, and of course, there are also multiple corresponding influence factors. Therefore, the product of the shaping field coil current and its influence factor is actually the sum of the products of the currents of multiple shaping field coils and their corresponding influence factors as the interference current of the shaping field coil. Subtract (linearly add or subtract) the above-mentioned interference currents of the toroidal field coil and the shaping field coil from the plasma current measurement signal to obtain the compensated plasma current measurement signal.

[0049] Among them, the determination method of the influence factors of the toroidal field coil and the shaping field coil is specifically as follows: By separately passing a long-term stable current through the toroidal field coil and the shaping field coil, that is, under the conditions of a stable field experiment (at this time, the central solenoid is not working, and the plasma current measurement value only represents the current generated in the vacuum chamber by the mutual inductance of the toroidal field coil or the shaping field coil), by obtaining the ratio between the plasma current measurement value and the corresponding coil current, the corresponding influence factor can be obtained.

[0050] Step 203: Obtain the eddy current on the vacuum chamber wall in real time, and perform secondary compensation on the compensated plasma current measurement signal in combination with the influence factor of the eddy current to obtain the true plasma current signal.

[0051] This step uses multiple single-turn loops to measure the loop voltage at different poloidal positions on the vacuum chamber wall. According to the loop voltage measured in real time by the single-turn loops and in combination with the LR circuit model, the eddy current at the corresponding poloidal position can be calculated. Among them, the LR circuit model is expressed as:

[0052]

[0053] Among them, is the resistance of the eddy current, is the self-inductance of the eddy current, is the eddy current, is the time, is the loop voltage.

[0054] After obtaining the eddy currents at different poloidal positions, the sum of the products of the eddy currents and the corresponding influence factors is used as the interference current of the eddy current, and this interference current of the eddy current is subtracted (linearly added or subtracted) from the compensated plasma current measurement signal to obtain the true plasma current signal.

[0055] An optional implementation manner: The determination method of the LR circuit model is specifically as follows: Use multiple single-turn loops to measure the loop voltage at different poloidal positions on the vacuum chamber wall. Under the assumption of quasi-toroidal symmetry, use the Biot-Savart law to calculate the self-inductance of the eddy current at each poloidal position. In the experiment of rapidly reducing the current of the shaping field coil, the loop voltage measured by the single-turn loop decreases exponentially. Perform exponential fitting on the curve of the measured value of the single-turn loop after the current of each shaping field coil drops to zero to obtain the exponent and amplitude of this curve. The self-inductance at different poloidal positions is multiplied by the corresponding exponent to obtain the resistance of the eddy current in the area of this poloidal position, and the LR circuit model of the eddy current is constructed based on the self-inductance and resistance:

[0056] An optional implementation manner: The determination method of the influence factor of the eddy current is specifically as follows: Pass an oscillating current through multiple shaping field coils (that is, in the oscillating field experiment, at this time the central solenoid is not working, that is, the plasma current measurement value only represents the current generated in the vacuum chamber due to the mutual inductance of the toroidal field coil and multiple shaping field coils), and measure the plasma current, toroidal field current, shaping field current, and eddy current. The specific measurement method is as described above and will not be elaborated here; then subtract (linearly add or subtract) the corresponding shaping field current measurement value and toroidal field current measurement value from the plasma current measurement value to obtain the plasma current only affected by the eddy current; finally, according to the plasma current only affected by the eddy current and the measured eddy current, use high-dimensional linear fitting to obtain the influence factor of the eddy current. It can be specifically expressed as:

[0057]

[0058] Among them, is the eddy current factor at different poloidal positions, is the plasma current affected only by eddy currents at different time points, is the eddy current at different poloidal positions and different time points.

[0059] Step 300: According to the deviation value between the true signal of the plasma current and the desired signal of the plasma current, based on this deviation value, the total amount of feedback control of the toroidal voltage required for the plasma region is obtained through feedback control, and in combination with the distribution matrix and the decoupling matrix, the feedback control amounts of the central solenoid and each shaping field coil are determined. Among them, the distribution matrix is used to ensure that the distribution of the plasma current does not change when realizing the coordinated control of the central solenoid and each shaping field coil; and the decoupling matrix contains the decoupling information of the central solenoid and each shaping field coil.

[0060] After obtaining the true signal of the plasma current, it is compared with the desired signal of the plasma current to obtain the deviation value between the two, and a PID controller is used to perform feedback control on this deviation value to obtain the total amount of toroidal voltage control required for the plasma region. It should be noted that this PID controller can adopt a conventional PID controller, and the optimal control amount output can be achieved by adjusting the parameters.

[0061] According to the plasma current drive principle, it can be known that by changing the currents of the central solenoid and each shaping field coil, the magnetic flux in the vacuum chamber will change, so as to achieve the purpose of driving the plasma current. The relationship between the total amount of toroidal voltage control of the plasma and the voltage control amounts of the central solenoid and each shaping field coil can be expressed as:

[0062]

[0063] Among them, is the total amount of toroidal voltage control of the plasma; is the inverse matrix of, representing the distribution matrix; are the voltage control amounts of the central solenoid and each shaping field coil.

[0064] An optional implementation manner, the calculation method of the distribution matrix specifically includes:

[0065] Step 301: Discretize the plasma region into a number of current loops. For example, discretize the plasma region into a 129×129 grid, and each grid represents a current loop. For the convenience of description, it will be simply referred to as Example 1 hereinafter.

[0066] Step 302: Analyze and obtain the mutual inductance matrix between the central solenoid, each shaping field coil, and the plasma current loop through the Biot-Savart law. Taking the above Example 1 as an example, a 17×16641 mutual inductance matrix can be obtained, where 16641 is the number of discrete current loops in the plasma region, and 17 is the number of the central solenoid and shaping field coils.

[0067] Step 303: Calculate the inverse matrix of the mutual inductance matrix between the central solenoid, each shaping field coil, and the plasma current loop through an asymmetric inversion algorithm. That is, taking the above Example 1 as an example, a 16641×17 inverse matrix can be obtained.

[0068] Step 304: Multiply the plasma current distribution by the inverse matrix to calculate the distribution matrix. This distribution matrix can ensure that when the plasma current changes, the distribution of the plasma current will not change. The calculation and execution of this distribution matrix reflect the coordination when the central solenoid and each shaping field coil drive the plasma. Among them, the acquisition method of the plasma current distribution is as follows: Based on the measurement results of the boundary poloidal magnetic field obtained under the steady-state discharge experiment conditions, and using the high-order polynomial fitting of the plasma equilibrium, the plasma current distribution is obtained. Specifically, the measurement results of the boundary poloidal magnetic field can be obtained through multiple boundary magnetic probes. Taking the above Example 1 as an example, the plasma current distribution can be obtained as a 1×16641 row vector.

[0069] Since there is a very strong coupling between the central solenoid and the shaping field coils, it is necessary to realize the decoupling control between the central solenoid and the shaping field coils. That is, when applying voltage to conduct coordinated control of the central solenoid and each shaping field coil, it is necessary to consider not only the changes in the resistance and inductance values of the coil itself, but also the influence of the current changes of other coils on it. An optional implementation manner, the decoupling control process specifically includes:

[0070] Step 305: Calculate the mutual inductance matrix between the central solenoid and each shaping field coil through the Biot-Savart law as the decoupling matrix;

[0071] Step 306: According to the total amount of loop voltage feedback control, the distribution matrix, and the decoupling matrix, the feedback control amounts of the central solenoid and each shaping field coil can be obtained. Specifically, multiply the total amount of loop voltage feedback control by the distribution matrix and the decoupling matrix, and the feedback control amount can be obtained. It should be noted that the feedback control amount here is the voltage control amount.

[0072] Step 400: According to the plasma current desired signal, calculate the total amount of loop voltage feedforward control required for the plasma region, and combine the distribution matrix and the decoupling matrix to determine the feedforward control amounts of the central solenoid and each shaping field coil.

[0073] The plasma circuit equation is expressed as:

[0074]

[0075] Among them, is the toroidal voltage of the plasma region; is the self-inductance of the plasma. The self-inductance of the plasma will vary due to different discharge conditions. However, since its variation range is generally small, the self-inductance of the plasma can be obtained by pre-estimation; is the true signal of the plasma current; is the internal resistance of the plasma; is the mutual inductance matrix from the plasma region to the poloidal field coils, and this matrix can be obtained by analyzing through the Biot-Savart law; is the current of the poloidal field coils.

[0076] Based on the above equations, according to the desired signal of the plasma current and the self-inductance and internal resistance of the plasma region, the total amount of feedforward control of the toroidal voltage required for the plasma region can be obtained. According to this total amount of feedforward control, and combined with the distribution matrix and decoupling matrix obtained in step 300 above (that is, multiplying the total amount of feedforward control by the distribution matrix and decoupling matrix), the feedforward control amounts of the central solenoid and each shaping field coil can be calculated. It should be noted that the feedforward control amount is also the voltage control amount.

[0077] An optional implementation manner, the estimation method of the plasma self-inductance specifically includes:

[0078] Step 401, calculate the self-inductance of each current loop of the plasma and the mutual inductance between other current loops through the Biot-Savart law to form a mutual inductance matrix. For example, taking the above Example 1 as an example, a 16641×16641 mutual inductance matrix can be obtained, where the diagonal terms are the self-inductances of each current loop, and the non-diagonal terms are the mutual inductances between different current loops.

[0079] Step 402, use the parallel inductance model to calculate the self-inductance of the plasma region. Among them, the calculation equation of the self-inductance of the conductive gas region is expressed as:

[0080]

[0081] Among them, is the current distribution of the conductive gas, is the mutual inductance matrix, represents an n×1 column vector (all values are 1), and n is the number of the central solenoid and the shaping field coils.

[0082] In an alternative embodiment, the internal resistance of the plasma region can be determined by the ratio of the loop voltage of the plasma region measured to the plasma current. Under the conditions of a steady-state discharge experiment, the resistance mainly plays a role in the plasma region. Therefore, the internal resistance of the plasma region can be directly determined by the above method.

[0083] Step 500: Linearly superimpose the feedback control amounts of the central solenoid and each shaping field coil with their corresponding feedforward control amounts to obtain the control amounts of the central solenoid and each shaping field coil, and accordingly, perform coordinated control on the central solenoid and each shaping field coil to achieve smooth driving of the plasma current.

[0084] It should be noted that there is no sequential execution relationship between Step 400 and Steps 100 - 300, but a parallel relationship, that is, Step 400 can be executed first, or later, or simultaneously.

[0085] The traditional copper-conductor tokamak plasma drive completely relies on a complex-structured ohmic coil, and the ohmic coils at different positions are in series. Any abnormality in any link cannot achieve smooth driving of the plasma current, and may even instantaneously induce a disruption, threatening the safe operation of the device. However, for the plasma current drive method proposed in this embodiment, the central solenoid and the shaping field coil are independently controlled and cooperate to maintain a zero-field state during plasma breakdown and achieve smooth driving of the plasma current, that is, both the central solenoid and the shaping field coil can provide a certain degree of ohmic drive ability. Therefore, even if a certain coil fails, the control weight can be transferred to other coils with ohmic drive ability, and smooth driving of the plasma current can still be achieved within a certain time range, which can reserve sufficient time for taking soft-landing shutdown measures and ensure the safe operation of the device.

[0086] Based on the same technical concept as above, this embodiment also proposes a composite coil ohmic drive system for a copper-conductor tokamak, as Figure 4 shown. The composite coil ohmic drive system proposed in this embodiment specifically includes:

[0087] A zero-field module, which is configured to: according to the pre-configured current ratio of each shaping field coil and the central solenoid, perform coordinated control on the central solenoid and each shaping field coil to ensure that the vacuum chamber is in a zero-field state during plasma breakdown. Among them, the configuration process of the current ratio of the central solenoid and each shaping field coil is as described in Step 100 above, and will not be elaborated here.

[0088] A measurement compensation module, which is configured to: during the plasma current drive, obtain the plasma current measurement signal in real time, and compensate the plasma current measurement signal by using the toroidal field coil current, the shaping field coil current, and the vacuum chamber eddy current to obtain the true plasma current signal.

[0089] A feedback control module, which is configured to: based on the deviation value between the true plasma current signal and the desired plasma current signal, feedback control to obtain the total amount of feedback control of the toroidal voltage required for the plasma region based on the deviation value, and combine the distribution matrix and the decoupling matrix to determine the feedback control amounts of the central solenoid and each shaping field coil. Among them, the distribution matrix is used to ensure that the distribution of the plasma current does not change when realizing the coordinated control of the central solenoid and each shaping field coil; and the decoupling matrix contains the decoupling information of the central solenoid and each shaping field coil. It should be noted that the specific implementation process of this feedback control module is as described in step 300 above, and will not be elaborated here.

[0090] A feedforward control module, which is configured to: according to the desired plasma current signal, calculate the total amount of feedforward control of the toroidal voltage required for the plasma region, and combine the distribution matrix and the decoupling matrix to determine the feedforward control amounts of the central solenoid and each shaping field coil. It should be noted that the specific implementation process of this feedforward control module is as described in step 400 above, and will not be elaborated here.

[0091] And an execution module, which is configured to: linearly superimpose the feedback control amounts of the central solenoid and each shaping field coil with their corresponding feedforward control amounts to obtain the control amounts of the central solenoid and each shaping field coil, and accordingly perform coordinated control on the central solenoid and each shaping field coil to achieve stable drive of the plasma current.

[0092] An alternative implementation, the above measurement compensation module further includes:

[0093] A signal acquisition unit, which is configured to: obtain the plasma current measurement signal, the toroidal field coil current, the current of each shaping field coil, and the eddy current in real time.

[0094] A first compensation unit, which is configured to: according to the toroidal field coil current and the current of each shaping field coil, and combine the influence factors corresponding to the toroidal field coil and each shaping field coil to perform a primary compensation on the plasma current measurement signal to obtain the compensated plasma current measurement signal.

[0095] And a second compensation unit, which is configured to: according to the eddy current on the vacuum chamber wall, and combine the influence factor of the eddy current to perform a secondary compensation on the compensated plasma current measurement signal to obtain the true plasma current signal.

[0096] It should be noted that the specific implementation processes of the module units in the compensation module are as described in the above steps 201 - 203, and will not be elaborated here.

[0097] The plasma current drive of the HL - 3 device is completed by using the plasma current drive method proposed in this embodiment, and Figure 5 the obtained discharge experimental results of the 4077 - shot of the HL - 3 device are shown. During the 4077 - shot discharge experiment of the HL - 3 device, through the central solenoid and the shaping field coils, and by using the composite coil drive technology, breakdown, plasma current formation, and early climb are realized. In the figure, IP_VV_2M represents the true value of the plasma current, Vloop_2M represents the toroidal voltage applied to the plasma, I_CS1_2M represents the discharge current of the central solenoid, I_PF6B_1 and I_PF6A_1 respectively represent the discharge currents of a set of shaping field coils PF6B and PF6A, and I_PF8B_1 and I_PF8A_1 respectively represent the discharge currents of a set of shaping field coils PF8B and PF8A.

[0098] It can be seen from the figure that the technology of realizing plasma current drive by the coordinated control of the central solenoid and the shaping field coils can achieve the stable drive of a plasma current of one million amperes, and keep the poloidal magnetic field voltage zero during the drive process. Thus, it can be known that the plasma current drive method proposed in this embodiment reduces the overall number of coils of the tokamak device and the difficulty of engineering implementation compared with the ohmic drive technology used in traditional copper - conductor tokamak devices, and can effectively achieve the stable drive of the plasma current. In addition, the central solenoid is mainly used to provide ohmic drive, and its current change range is the largest, dropping from +60 kA all the way to about - 40 kA. And in the time period of 0.6 - 0.8 s, the current of the central solenoid is always zero and it does not provide ohmic drive ability. If it is the ohmic coil drive method of a traditional copper - conductor tokamak, the plasma current will drop rapidly or even break at this time. However, by using the plasma current drive method proposed in this embodiment, when the central solenoid cannot provide ohmic drive ability, the control weight of ohmic drive is transferred to the other two sets of shaping field coils. By changing the current magnitude of the shaping field coils in the time period of 0.6 - 0.8 s, not only the smooth climb of the plasma current is maintained, but also a stable discharge with a divertor configuration of one million amperes is realized.

[0099] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0100] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0101] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0103] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present application. It should be understood that the above are only specific embodiments of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for ohmic driving of a composite coil of a copper conductor tokamak, characterized in that, Including: According to the pre-configured current ratio of each shaping field coil and the central solenoid, the central solenoid and each shaping field coil are coordinately controlled to ensure that the vacuum chamber is in a zero-field state during plasma breakdown; During plasma current drive, a plasma current measurement signal is acquired in real time, and the plasma current measurement signal is compensated by using the toroidal field coil current, the shaping field coil current, and the vacuum chamber eddy current to obtain a true plasma current signal; According to the deviation value between the true plasma current signal and the desired plasma current signal, based on the deviation value feedback control, the total amount of feedback control of the toroidal voltage required in the plasma region is obtained, and in combination with the distribution matrix and the decoupling matrix, the feedback control amounts of the central solenoid and each shaping field coil are determined; According to the desired plasma current signal, the total amount of feedforward control of the toroidal voltage required in the plasma region is calculated, and in combination with the distribution matrix and the decoupling matrix, the feedforward control amounts of the central solenoid and each shaping field coil are determined; The feedback control amounts of the central solenoid and each shaping field coil are linearly superimposed with their corresponding feedforward control amounts to obtain the control amounts of the central solenoid and each shaping field coil, and based on this, the central solenoid and each shaping field coil are coordinately controlled to achieve stable drive of the plasma current; Wherein, the distribution matrix is used to ensure that the distribution of the plasma current does not change when the central solenoid and each shaping field coil are coordinately controlled; the decoupling matrix contains the decoupling information of the central solenoid and each shaping field coil.

2. The composite coil ohmic driving method of a copper conductor Tokamak according to claim 1, characterized in that The configuration process of the current ratio of the central solenoid and each shaping field coil specifically includes: Based on the magnetic field distribution generated by the central solenoid and each shaping field coil in the vacuum chamber region, an initial shaping field coil discharge scheme with zero-field matching is given based on the principle that the poloidal magnetic field at the geometric center of the vacuum chamber region is zero; An array composed of multiple single-turn loops is used to measure the toroidal voltage distribution on the vacuum chamber wall during breakdown. Based on the principle of minimizing the weighted toroidal voltage, the initial shaping field coil discharge scheme with zero-field matching is adjusted to correct the eddy current on the vacuum chamber wall to determine the optimal shaping field coil discharge scheme with zero-field matching.

3. A composite coil ohmic driving method for a copper conductor tokamak according to claim 2, characterized in that, The formation process of the initial shaping field coil discharge scheme with zero-field matching specifically includes: A magnetic probe array is used to measure the magnetic field distribution when the single-pass central solenoid and each shaping field coil are energized; Based on the Biot-Savart law, the finite element analysis method is used to calculate the magnetic field distribution generated by the central solenoid and each shaping field coil; The measured magnetic field distribution is used to verify whether the calculated magnetic field distribution meets the requirements. If so, the subsequent steps are continued; otherwise, the previous step is returned to recalculate; The magnetic field distribution of each shaping field coil obtained by calculation is used to compensate the poloidal magnetic field generated by the central solenoid obtained by calculation. Based on the principle that the poloidal magnetic field in the geometric center region is zero, the current ratio of each shaping field coil and the central solenoid current is configured to form an initial shaping field coil discharge scheme with zero-field matching.

4. A composite coil ohmic driving method for a copper conductor tokamak according to claim 2, characterized in that, The formation process of the optimal shaping field coil discharge scheme with zero-field matching specifically includes: Measure the loop voltage in a certain poloidal region of the vacuum chamber during plasma breakdown through a single-turn loop, calculate the self-inductance of the vacuum chamber wall in this region based on the spatial characteristic information of the single-turn loop, fit the decay curve of the toroidal voltage after breakdown using an exponential function to obtain the characteristic time of this region, and then obtain the resistance of this region; the poloidal distributions of the inductance and resistance on the vacuum chamber wall can be measured using multiple single-turn loops; Calculate the mutual inductance generated by the shaped field coil on the vacuum chamber wall in its adjacent region using the spatial dimensions of the shaped field coil; Based on the measured eddy current distribution on the vacuum chamber wall, inversely calculate the poloidal magnetic flux distribution and time evolution curve required to compensate for the eddy current, and accordingly obtain the evolution curve of the current in each shaped field coil; Weight the single-turn loops according to the density of the single-turn loops, and the weighting coefficient is the reciprocal of the distance between two adjacent single-turn loops. Taking the minimum of the weighted average value of the single-turn loops as the index, adjust the current waveforms of each shaped field coil to obtain the best eddy current compensation effect, thereby determining the discharge scheme of the shaped field coil for the optimal null field.

5. A method for ohmic driving of a composite coil of a copper conductor tokamak according to claim 1, characterized in that, The specific calculation method of the distribution matrix includes: Discretize the plasma region into several current loops; Analytically obtain the first mutual inductance matrix between the central solenoid, each shaped field coil and several current loops through the Biot-Savart law; Calculate the inverse matrix of the first mutual inductance matrix through an asymmetric inversion algorithm; Multiply the plasma current distribution by the inverse matrix to calculate the distribution matrix.

6. A method for ohmic driving of a composite coil of a copper conductor Tokamak according to claim 5, characterized in that The decoupling matrix is specifically the mutual inductance matrix between the central solenoid and each shaped field coil calculated through the Biot-Savart law; Multiply the total loop voltage feedback control amount by the distribution matrix and the decoupling matrix to obtain the feedback control amounts of the central solenoid and each shaped field coil.

7. A composite coil ohmic drive method for a copper conductor tokamak according to claim 5, characterized in that, The decoupling matrix is specifically the mutual inductance matrix between the central solenoid and each shaped field coil calculated through the Biot-Savart law; Multiply the total loop voltage feedforward control amount by the distribution matrix and the decoupling matrix to obtain the feedforward control amounts of the central solenoid and each shaped field coil.

8. A method for ohmic driving of a composite coil of a copper conductor Tokamak according to claim 7, characterized in that, The specific calculation method of the total loop voltage feedforward control amount includes: Calculate the total loop voltage feedforward control amount required for the plasma region according to the plasma current desired signal and the self-inductance and internal resistance of the plasma region; Among them, the estimation method of the self-inductance of the plasma region specifically includes: Calculate the self-inductance of each current loop and the mutual inductance with other current loops through the Biot-Savart law to form a second mutual inductance matrix. The diagonal terms of the second mutual inductance matrix are the self-inductances of each current loop, and the non-diagonal terms are the mutual inductances between different current loops; Calculate the self-inductance of the plasma region using the parallel inductance model; The estimation method of the internal resistance of the plasma region specifically includes: Under stable discharge experimental conditions, measure the loop voltage and the plasma current of the plasma region; Obtain the ratio of the loop voltage to the plasma current of the plasma region, which is the internal resistance of the plasma region.

9. A method for ohmic driving of a composite coil of a copper-conductor tokamak according to any one of claims 1-8, characterized in that, Compensating the plasma current measurement signal by using the toroidal field coil current, the shaping field coil current, and the vacuum vessel eddy current specifically includes: Obtaining the plasma current measurement signal in real time; Obtaining the toroidal field coil current and each shaping field coil current in real time, and performing a primary compensation on the plasma current measurement signal by combining the influence factors corresponding to the toroidal field coil and each shaping field coil to obtain a compensated plasma current measurement signal; Obtaining the eddy current on the vacuum vessel wall in real time, and performing a secondary compensation on the compensated plasma current measurement signal by combining the influence factor of the eddy current to obtain the true plasma current signal.

10. A method for ohmic driving of a composite coil of a copper conductor Tokamak according to claim 9, characterized in that, The primary compensation for the plasma current measurement signal specifically includes: Measuring the toroidal field coil current and each shaping field coil current in real time; Taking the product of the toroidal field coil current and its influence factor as the interference current of the toroidal field coil, and taking the sum of the products of each shaping field coil current and its corresponding influence factor as the interference current of the shaping field coil; Subtracting the interference current of the toroidal field coil and the interference current of the shaping field coil from the plasma current measurement signal to obtain a compensated plasma current measurement signal; The method for determining the influence factors of the toroidal field coil and each shaping field coil is: By separately passing a stable current through the toroidal field coil and each shaping field coil, and measuring the corresponding toroidal field coil current, each shaping field coil current, and their corresponding plasma current values; Taking the ratio between the plasma current value and the corresponding coil current as the influence factor of this coil.

11. A method for ohmic driving of a composite coil of a copper conductor Tokamak according to claim 9, characterized in that, The secondary compensation for the compensated plasma current measurement signal specifically includes: Measuring the toroidal voltage at different poloidal positions on the vacuum vessel wall in real time, and calculating the eddy current at the corresponding poloidal positions by combining the LR circuit model; wherein, the LR circuit model characterizes the relationship between the toroidal voltage and the self-inductance and resistance of the eddy current; Taking the sum of the products of the toroidal voltage at each poloidal position and its corresponding influence factor as the interference current of the eddy current; Subtracting the interference current of the eddy current from the compensated plasma current measurement signal to obtain the true plasma current signal; The determination method of the influence factor of the eddy current is: By passing an oscillating current through multiple shaping field coils, and measuring the corresponding plasma current, toroidal field current, shaping field current, and eddy current; Subtracting the corresponding shaping field current measurement value and toroidal field current measurement value from the plasma current measurement value to obtain the plasma current only affected by the eddy current; According to the plasma current only affected by the eddy current and the eddy current measurement value, using high-dimensional linear fitting to obtain the influence factor of the eddy current.

12. A composite coil ohmic drive system for a copper conductor tokamak, characterized in that, Including: A zero-field module, which is configured to: according to the pre-configured current ratio of the central solenoid and each shaping field coil, perform coordinated control on the central solenoid and each shaping field coil to ensure that the vacuum vessel is in a zero-field state during plasma breakdown; Measurement compensation module, which is configured to: during plasma current drive, acquire the plasma current measurement signal in real time, and compensate the plasma current measurement signal by using the toroidal field coil current, the shaping field coil current, and the vacuum vessel eddy current to obtain the true plasma current signal; Feedback control module, which is configured to: based on the deviation value between the true plasma current signal and the desired plasma current signal, feedback control to obtain the total amount of feedback control of the toroidal voltage required in the plasma region based on the deviation value, and determine the feedback control amounts of the central solenoid and each shaping field coil in combination with the distribution matrix and the decoupling matrix; Feedforward control module, which is configured to: calculate the total amount of feedforward control of the toroidal voltage required in the plasma region according to the desired plasma current signal, and determine the feedforward control amounts of the central solenoid and each shaping field coil in combination with the distribution matrix and the decoupling matrix; And an execution module, which is configured to: linearly superimpose the feedback control amounts of the central solenoid and each shaping field coil with their corresponding feedforward control amounts to obtain the control amounts of the central solenoid and each shaping field coil, and perform coordinated control on the central solenoid and each shaping field coil accordingly to achieve stable drive of the plasma current; Wherein, the distribution matrix is used to ensure that the distribution of the plasma current does not change when realizing the coordinated control of the central solenoid and each shaping field coil; the decoupling matrix contains the decoupling information of the central solenoid and each shaping field coil; The configuration process of the current ratio of the central solenoid and each shaping field coil specifically includes: Based on the magnetic field distribution generated by the central solenoid and each shaping field coil in the vacuum vessel region, a discharge scheme of the shaping field coil for the initial zeroing field is given with the poloidal magnetic field at the geometric center of the vacuum vessel region being zero as the reference; Use an array composed of multiple single-turn loops to measure the toroidal voltage distribution on the vacuum vessel wall during breakdown, and adjust the discharge scheme of the shaping field coil for the initial zeroing field to correct the eddy current on the vacuum vessel wall with the principle of minimizing the weighted toroidal voltage, and determine the optimal discharge scheme of the shaping field coil for the zeroing field.

13. A composite coil ohmic drive system for a copper conductor tokamak according to claim 12, characterized in that, The compensation module further includes: Signal acquisition unit, which is configured to: acquire the plasma current measurement signal, the toroidal field coil current, the current of each shaping field coil, and the eddy current on the vacuum vessel wall in real time; First compensation unit, which is configured to: perform a first compensation on the plasma current measurement signal according to the toroidal field coil current and the current of each shaping field coil, and in combination with the influence factors corresponding to the toroidal field coil and each shaping field coil, to obtain the compensated plasma current measurement signal; And a second compensation unit, which is configured to: perform a second compensation on the compensated plasma current measurement signal according to the eddy current on the vacuum vessel wall and in combination with the influence factor of the eddy current to obtain the true plasma current signal.

14. A composite coil ohmic drive system for a copper conductor Tokamak according to claim 12, characterized in that, The calculation method of the distribution matrix specifically includes: Discretize the plasma region into several current loops; The first mutual inductance matrix between the central solenoid, each shaping field coil and several of the current loops is analytically obtained through the Biot-Savart law; The inverse matrix of the first mutual inductance matrix is calculated through an asymmetric inversion algorithm; The plasma current distribution is multiplied by the inverse matrix to calculate the distribution matrix.

15. A composite coil ohmic drive system for a copper conductor tokamak according to claim 14, characterized in that, The decoupling matrix is specifically the mutual inductance matrix between the central solenoid and each shaping field coil obtained by calculating through the Biot-Savart law; The total amount of loop voltage feedback control is multiplied by the distribution matrix and the decoupling matrix to obtain the feedback control amounts of the central solenoid and each shaping field coil.

16. A composite coil ohmic drive system for a copper conductor Tokamak according to claim 14, characterized in that, The decoupling matrix is specifically the mutual inductance matrix between the central solenoid and each shaping field coil obtained by calculating through the Biot-Savart law; The total amount of loop voltage feedforward control is multiplied by the distribution matrix and the decoupling matrix to obtain the feedforward control amounts of the central solenoid and each shaping field coil.

17. A composite coil ohmic drive system for a copper conductor tokamak according to claim 16, characterized in that, The calculation method of the total amount of loop voltage feedforward control specifically includes: According to the plasma current desired signal and the self-inductance and internal resistance of the plasma region, the total amount of loop voltage feedforward control required for the plasma region is calculated; Among them, the estimation method of the self-inductance of the plasma region specifically includes: The self-inductance of each current loop and the mutual inductance between other current loops are calculated through the Biot-Savart law to form a second mutual inductance matrix, where the diagonal terms of the second mutual inductance matrix are the self-inductances of each current loop, and the non-diagonal terms are the mutual inductances between different current loops; The self-inductance of the plasma region is calculated using a parallel inductance model; The estimation method of the internal resistance of the plasma region specifically includes: Under the stable discharge experimental conditions, the loop voltage and the plasma current of the plasma region are measured; The ratio of the loop voltage to the plasma current of the plasma region is obtained, which is the internal resistance of the plasma region.

18. An electronic device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1-11 are implemented.

Images