Energy efficiency optimization control method and system for crystal furnace

Abstract

The invention provides an energy efficiency optimization control method and system for a crystal furnace, and relates to the field of crystal furnaces, and the control method comprises the steps: obtaining the alternating current information of an alternating current and the induced magnetic field information of an induced magnetic field in real time after a first starting signal of an induction heating power supply is received; if the intensity of the induced magnetic field is larger than the first preset intensity, compensation current information is obtained according to the alternating current information, and the compensation current information comprises a compensation current value and a compensation current direction of compensation current; and the compensation current information is sent to the power driving module, so that the compensation current corresponding to the compensation current information is input to the compensation coil. According to the scheme, the compensation current corresponding to the alternating current is input into the compensation coil, interference of the induced magnetic field on the heating magnetic field is effectively offset, it is ensured that the heating magnetic field can stably and intensively act on the crucible, energy loss caused by magnetic field distortion is reduced, and energy consumption optimization is achieved.

Description

Technical Field

[0001] This application relates to the technical field of crystal furnaces, and particularly to an energy efficiency optimization control method and system for a crystal furnace. Background Art

[0002] In the field of modern crystal material preparation, a crystal furnace is a key device for achieving high-quality crystal growth. With the continuous progress of technology, the requirements for the quality and performance of crystals are increasing day by day, which makes the energy utilization efficiency and magnetic field stability during the crystal growth process important issues that need to be solved urgently.

[0003] When a traditional crystal furnace uses induction heating technology for crystal growth, after an alternating current is passed through the induction coil, although heat can be generated in the crucible to melt the growth raw materials, at the same time, due to the electromagnetic induction phenomenon, strong eddy currents will be generated in the crucible. These strong eddy currents then form an induced magnetic field, which is always opposite to the alternating magnetic field.

[0004] The existence of the induced magnetic field seriously affects the heating efficiency during the crystal growth process. On the one hand, it will change the direction of the heating magnetic field, causing the heating magnetic field to twist or even bypass the crucible, and unable to effectively pass through the crucible to heat the raw materials. This not only results in a large amount of energy being wasted during transmission, but also significantly increases the energy consumption required for crystal growth and the production cost. On the other hand, the unstable magnetic field environment will also have a negative impact on the growth quality of the crystal, easily causing defects inside the crystal and reducing the quality and performance of the crystal. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, this application aims to provide an energy efficiency optimization control method and system for a crystal furnace to achieve energy efficiency optimization of the crystal furnace.

[0006] In a first aspect, this application proposes an energy efficiency optimization control method for a crystal furnace, where the crystal furnace includes: A furnace body, which has a growth space inside. A support assembly is provided at the bottom of the growth space inside the furnace body, and a crucible for accommodating growth raw materials is provided on the support assembly; A heating assembly, which includes an induction coil surrounding the outer periphery of the crucible. The induction coil is connected to an induction heating power supply, and the induction heating power supply is used to provide an alternating current into the induction coil. The alternating magnetic field formed by the alternating current can be used as the heating magnetic field for the growth raw materials; A compensation coil, which is provided on the side of the induction coil close to the crucible. The compensation coil is connected to a compensation power supply, and the compensation power supply includes a power driving module, and the power driving module is used to adjust the compensation current input to the compensation coil; The monitoring component is arranged around the crucible and is used to monitor the induced magnetic field in the crucible. The induced magnetic field is formed by a strong eddy current generated in the crucible under the action of an alternating magnetic field generated after an alternating current is passed through the induction coil. The control method includes the following steps: After receiving the first start signal of the induction heating power supply, the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field are obtained in real time. The alternating current information includes the alternating current value and the alternating current direction, and the induced magnetic field information includes the induced magnetic field intensity. If the induced magnetic field intensity is greater than the first preset intensity, corresponding compensation current information is obtained according to the alternating current information. The compensation current information includes the compensation current value and the compensation current direction of the compensation current. Among them, the compensation current corresponding to the compensation current information can cancel the interference of the induced magnetic field on the heating magnetic field. The compensation current information is sent to the power drive module to input the compensation current corresponding to the compensation current information into the compensation coil.

[0007] According to the technical solution provided by the present application, the compensation current value is the same as the alternating current value, and the compensation current direction is opposite to the alternating current direction.

[0008] According to the technical solution provided by the present application, obtaining the compensation current information according to the alternating current information specifically includes the following steps: Obtain the current crystal growth stage, and the crystal growth stage includes a heating and melting stage, a crystallization stage, and a cooling stage. If the current crystal growth stage is the heating and melting stage, the product of the first coefficient and the alternating current value is used as the compensation current value, and the direction opposite to the alternating current direction is used as the compensation current direction. The first coefficient is greater than 1. If the current crystal growth stage is the cooling stage, the product of the second coefficient and the alternating current value is used as the compensation current value, and the second coefficient is greater than or equal to 0 and less than 1.

[0009] According to the technical solution provided by the present application, after obtaining the current crystal growth stage, the following steps are further included: If the current crystal growth stage is the crystallization stage, the temperature gradient and the magnetic field gradient are obtained in real time, and the compensation current information is obtained according to the temperature gradient, the magnetic field gradient, and the alternating current information. The temperature gradient is the temperature difference at different positions in the crucible, and the magnetic field gradient is the magnetic field intensity difference at different positions in the furnace body.

[0010] According to the technical solution provided by the present application, obtaining the compensation current information according to the temperature gradient, the magnetic field gradient, and the alternating current information specifically includes the following steps: Retrieve and traverse the marginal benefit database to obtain alternative current information corresponding to the growth parameter combination corresponding to the temperature gradient, the magnetic field gradient, and the alternating current information, and use this alternative current information as the compensation current information; Among them, the marginal benefit database includes multiple groups of growth parameter combinations and alternative current information corresponding to each group of growth parameter combinations. The growth parameter combination is a combination formed by a preset temperature gradient, a preset magnetic field gradient, and preset alternating current information. The alternative current information is the current information that maximizes the marginal benefit under the growth parameter combination. The marginal benefit is comprehensively obtained from the crystal furnace energy efficiency index and the crystal growth quality index.

[0011] According to the technical solution provided by the present application, the method further includes constructing the marginal benefit database; the constructing of the marginal benefit database specifically includes the following steps: Obtain a finite element model corresponding to the crystal furnace and a test sample set. The test sample set includes multiple groups of the growth parameter combinations and multiple test current information corresponding to each group of the growth parameter combinations; Input each group of the growth parameter combinations and the multiple test current information corresponding to each group of the growth parameter combinations into the finite element model in sequence to obtain the marginal effect value corresponding to each test current information in each group of the growth parameter combinations. The marginal effect value is obtained from the energy consumption and the crystal quality index. The crystal quality index at least includes dislocation density and impurity content; Use the test current information with the maximum marginal effect value in the growth parameter combination as the alternative current information corresponding to this group of the growth parameter combinations to obtain the marginal benefit database.

[0012] According to the technical solution provided by the present application, the compensation coil is formed by connecting a plurality of sub-coils. Each sub-coil is connected in parallel to the same compensation power supply; the induced magnetic field intensity is obtained from the point magnetic field intensities read at multiple positions corresponding to the orientations of the respective sub-coils; Before the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field are obtained in real time, the following steps are further included: Obtain the point magnetic field intensities read at positions corresponding to the orientations of the respective sub-coils, and obtain the average value of the first point magnetic field intensities; Judge whether the difference between all the point magnetic field intensities and the average value of the first point magnetic field intensities is less than a first preset deviation; Obtaining the induced magnetic field information of the induced magnetic field includes the following steps: If so, use the average value of the magnetic field intensity at the first point as the induced magnetic field intensity.

[0013] According to the technical solution provided by the present application, each of the sub-coils has an adjustable resistor connected in series therewith; After determining whether the difference between the magnetic field intensity at all points and the average value of the magnetic field intensity at the points is less than a first preset deviation, the following steps are further included: If not, use the sub-coil corresponding to the azimuth of the magnetic field intensity at the point whose difference from the average value of the magnetic field intensity at the first point is greater than or equal to the first preset deviation as the target sub-coil; Use the average value of the magnetic field intensity at the second point of the sub-coils other than the target sub-coil as the induced magnetic field intensity; Based on the average value of the magnetic field intensity at the second point and the magnetic field intensity at the azimuth corresponding to the target sub-coil, obtain an adjusted resistance value; Adjust the adjustable resistor connected in series with the target sub-coil with the adjusted resistance value to optimize the magnetic field distribution in the crystal furnace.

[0014] According to the technical solution provided by the present application, the induced magnetic field information further includes an induced magnetic field change rate; After obtaining the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field in real time, the following steps are further included: If the induced magnetic field intensity is less than or equal to a first preset intensity and the induced magnetic field change rate is less than or equal to a first preset change rate, turn off the compensation power supply and obtain the current crystal growth stage; If the current crystal growth stage is the heating and melting stage, retrieve a preset heating curve, increase the heating temperature corresponding to the next heating moment adjacent to the current moment to obtain an updated heating curve; the preset heating curve is a curve composed of the heating temperatures corresponding to each heating moment within the heating and melting stage.

[0015] In a second aspect, the present application proposes an energy efficiency optimization control system for a crystal furnace, which is used to implement the energy efficiency optimization control method for a crystal furnace as described above; including the following steps: An acquisition module, configured to, after receiving a first start signal of the induction heating power supply, obtain the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field in real time; the alternating current information includes an alternating current value and an alternating current direction, and the induced magnetic field information includes an induced magnetic field intensity; A judgment module, configured to obtain corresponding compensation current information according to the alternating current information if the induced magnetic field intensity is greater than a first preset intensity, where the compensation current information includes the compensation current value and the compensation current direction of the compensation current; wherein, the compensation current corresponding to the compensation current information can cancel the interference of the induced magnetic field on the heating magnetic field. A control module, configured to send the compensation current information to the power drive module to input the compensation current corresponding to the compensation current information into the compensation coil.

[0016] Compared with the prior art, the beneficial effects of the present application are as follows: When it is monitored that the induced magnetic field intensity is greater than the first preset intensity, the present application generates compensation current information according to the alternating current information. By inputting the compensation current corresponding to the alternating current into the compensation coil, the interference of the induced magnetic field on the heating magnetic field can be effectively canceled. This ensures that the heating magnetic field can act on the crucible stably and concentratedly, reduces the energy loss caused by magnetic field distortion, improves the efficiency of induction heating, and thus realizes energy consumption optimization. For example, originally, due to the interference of the induced magnetic field, part of the energy was wasted in the area deviating from the crucible during the heating process, while the reverse magnetic field generated by the compensation current can correct the magnetic field distribution, making the energy more effectively used for heating the raw materials in the crucible. At the same time, the alternating current information and the induced magnetic field information are obtained in real time, and a quick response is made according to the actual situation. As the situation in the crucible changes during the crystal growth process, the induced magnetic field intensity will also change dynamically. This method can capture these changes in time and adjust the compensation current accordingly, always maintaining an effective cancellation of the induced magnetic field and maintaining the high efficiency of the heating process, avoiding an increase in energy consumption caused by magnetic field instability. Description of the Drawings

[0017] Figure 1 It is a flowchart of the steps of the energy efficiency optimization control method for a crystal furnace provided by the present application; Figure 2 It is a schematic structural diagram of a crystal furnace provided by the present application; Figure 3 It is a schematic cross-sectional view of a crystal furnace provided by the present application.

[0018] The text labels in the figure are indicated as: 1. Furnace body; 2. Seed crystal rod; 3. Crucible; 4. Induction coil; 5. Compensation coil; 6. Support assembly. Detailed Embodiments

[0019] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention, rather than limiting the invention. It should be noted that, for the sake of description, only the parts related to the invention are shown in the drawings.

[0020] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] Embodiment 1 As mentioned in the background art, in view of the problems in the prior art, the present application proposes an energy efficiency optimization control method for a crystal furnace. Please refer to Figure 1 、 2 As shown, the crystal furnace includes: A furnace body 1, within which there is a growth space. Inside the growth space and at the bottom of the furnace body 1, there is a support assembly 6, and on the support assembly 6, there is a crucible 3 for accommodating the growth raw material. Specifically, the support assembly 6 is used to support and rotate the crucible 3, and at the top of the furnace body 1, there is a seed crystal rod 2 perpendicular to the crucible 3 and inserted into the crucible 1.

[0022] A heating assembly, the heating assembly includes an induction coil 4 disposed around the outer periphery of the crucible 3. The induction coil 4 is connected to an induction heating power supply, and the induction heating power supply is used to provide an alternating current to the induction coil 4. The alternating magnetic field formed by the alternating current can be used as the heating magnetic field for the growth raw material. Specifically, the induction coil 4 is made of a metal material with good electrical conductivity (such as copper). Its parameters such as the number of turns, wire diameter, and coil shape are designed according to the power requirements of the crystal furnace, the size of the crucible 3, and the characteristics of the required heating magnetic field, etc. Exemplarily, the number of turns and wire diameter of the induction coil 4 are proportional to the size of the crucible 3 and the required heating power. For a larger-sized crucible 3 and higher heating power requirements, an induction coil 4 with more turns and a thicker wire diameter may be used.

[0023] When the induction heating power supply provides an alternating current to the induction coil 4, according to the law of electromagnetic induction, the alternating current will generate an alternating magnetic field around the induction coil 4. This alternating magnetic field will pass through the crucible 3. Since the growth raw material (generally a conductor or semiconductor material) in the crucible 3 is in the magnetic field, an induced electromotive force will be generated inside the raw material. When the raw material forms a closed loop (for example, the crucible 3 itself can be part of the closed loop), eddy currents will be generated. The eddy currents flow inside the raw material, and due to the resistance effect of the raw material, Joule heat will be generated, thereby realizing the heating of the growth raw material.

[0024] A compensation coil 5, the compensation coil 5 is disposed on the side of the induction coil 4 close to the crucible 3. The compensation coil 5 is connected to a compensation power supply, and the compensation power supply includes a power drive module. The power drive module is used to adjust the compensation current input to the compensation coil 5. Specifically, when an induced magnetic field is generated in the crucible 3 and interferes with the heating magnetic field, the compensation coil 5 generates a magnetic field by passing a compensation current. The direction of this compensation magnetic field is opposite to that of the induced magnetic field, and its magnitude is adjusted as needed, so as to cancel the interference of the induced magnetic field on the heating magnetic field. For example, if the induced magnetic field enhances the heating magnetic field in a certain direction, the magnetic field generated by the compensation coil 5 weakens the heating magnetic field in that direction, restoring the heating magnetic field to an ideal state.

[0025] Among them, the power drive module includes a power amplifier circuit and a drive circuit. The power amplifier circuit can amplify the control signal to a sufficient power level to drive the compensation coil 5 to generate the required compensation current. The drive circuit controls the working state of the power amplifier circuit according to the received compensation current information. After receiving the compensation current information (including the compensation current value and the compensation current direction) sent by the control unit, the drive circuit processes the signal, and then controls the power amplifier circuit to convert the input power supply signal into a compensation current with appropriate value and direction, and inputs it into the compensation coil 5.

[0026] Specifically, a heat insulation layer made of high-temperature resistant and low-thermal conductivity materials such as ceramic fiber is provided in the furnace body 1. It surrounds the crucible 3, the heating component and the compensation coil 5, playing a role in reducing heat dissipation, concentrating the heat in the growth space, and ensuring that the growth raw materials stably crystallize in a high-temperature environment. A good heat insulation structure can keep the temperature in the furnace within a suitable range, reduce energy consumption, and at the same time ensure the stability of the crystal growth rate.

[0027] Furthermore, electromagnetic shielding materials can be used to properly isolate the induction coil 4 and the compensation coil 5. Electromagnetic shielding materials (such as metals like copper and aluminum) can absorb and reflect electromagnetic fields, reducing the electromagnetic coupling between the coils. A metal shielding cover with a high magnetic permeability can be placed between the induction coil 4 and the compensation coil 5 to separate the induction coil 4 and the compensation coil 5. For example, a copper shielding cover with a thickness of 2 mm is used to surround the induction coil 4 and the compensation coil 5 to form an electromagnetic isolation area. At the same time, ensure that the shielding cover is grounded to guide the induced current to the ground and reduce the impact on other components.

[0028] A monitoring component, the monitoring component is arranged around the crucible 3 and is used to monitor the induced magnetic field in the crucible 3. The induced magnetic field is formed by strong eddy currents generated in the crucible 3 under the action of an alternating magnetic field generated after an alternating current is passed through the induction coil 4. Specifically, the monitoring components can be selected as Hall sensors or magnetoresistive sensors for monitoring magnetic field information, and current sensors for monitoring alternating current information. These sensors are installed at appropriate positions around the crucible 3. The magnetic field sensor should be installed at a position where it can accurately sense the magnetic field changes inside the crucible 3 and be protected from other magnetic field interferences. It can be fixed inside the furnace body 1 near the crucible 3 through a bracket. The current sensor is installed in the circuit of the induction coil 4 and is connected in series with the induction coil 4 or through electromagnetic coupling. The sensors transmit the monitored signals (magnetic field intensity signal, alternating current signal) to the control unit through signal lines. The signal lines should use shielded wires to reduce the impact of external electromagnetic interference on signal transmission.

[0029] As Figure 3 shown, the control method includes the following steps: After receiving the first start signal of the induction heating power supply, the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field are obtained in real time; the alternating current information includes the alternating current value and the alternating current direction, and the induced magnetic field information includes the induced magnetic field intensity; If the induced magnetic field intensity is greater than the first preset intensity, the corresponding compensation current information is obtained according to the alternating current information. The compensation current information includes the compensation current value and the compensation current direction of the compensation current; wherein, the compensation current corresponding to the compensation current information can cancel the interference of the induced magnetic field on the heating magnetic field; optionally, the first preset intensity is 0.5 T (Tesla).

[0030] The compensation current information is sent to the power drive module to input the compensation current corresponding to the compensation current information into the compensation coil 5.

[0031] In a preferred embodiment, the compensation current value is the same as the alternating current value, and the compensation current direction is opposite to the alternating current direction.

[0032] Describe the working principle: When the magnetic field interference is effectively cancelled, the heating magnetic field can act on the growth raw materials more uniformly and stably. In the absence of interference, the eddy current distribution generated by the alternating magnetic field in the crucible 3 is more regular, enabling the raw materials to absorb the magnetic field energy more fully and convert it into heat energy. For example, during crystal growth, for high-purity materials such as single-crystalline silicon, uniform and stable heating helps the atoms to be arranged orderly in the molten state, reducing the energy loss caused by local overheating or overcooling. Originally, due to the interference of the induced magnetic field, only 70% of the electromagnetic energy might be effectively used for heating the raw materials. After the magnetic field is cancelled, this ratio can be increased to 90%, thereby reducing the energy input required to achieve the same heating effect. At the same time, the stable heating magnetic field helps to precisely control the temperature of crystal growth. By cancelling the magnetic field interference, the temperature fluctuation range can be controlled within a smaller interval. For example, for the growth of some optical crystals, the temperature fluctuation is required to be controlled within ±1°C. When the magnetic field interference is effectively controlled, the output power of the induction heating power supply can be adjusted more precisely, thereby achieving high-precision control of the crystal growth temperature, reducing the waste of raw materials and the generation of defective products caused by temperature runaway, and further optimizing the energy efficiency of crystal growth. Magnetic field interference will cause the heating components and other related components to bear uneven electromagnetic forces and thermal stresses. When these interferences are cancelled, the stress on the components is more uniform, reducing the damage of the components caused by factors such as local overheating and electromagnetic force concentration. For example, the induction coil 4 works in a stable magnetic field environment, and the current distribution inside it is more uniform, reducing the risk of aging and damage of the coil insulation layer caused by local overheating. The extension of the equipment service life means reducing the frequency of equipment replacement and maintenance, and reducing the equipment maintenance cost. At the same time, the long-term stable operation of the equipment also helps to ensure the continuity and stability of crystal production, improving the energy efficiency and economy of the entire crystal growth system.

[0033] In a preferred embodiment, obtaining the compensation current information according to the alternating current information specifically includes the following steps: Obtain the current crystal growth stage, where the crystal growth stage includes a heating and melting stage, a crystallization stage, and a cooling stage; Specifically, set the judgment criteria for the crystal growth stage and the corresponding coefficients for different stages in the control unit. Optionally, monitor the temperature in the crucible 3 through a temperature sensor, and judge the current crystal growth stage according to the preset temperature range.

[0034] Exemplarily, according to the set judgment rule, obtain the current crystal growth stage. The set judgment rule is: if the temperature in the crucible 3 is lower than the melting point of the growth raw materials, it is determined to be in the heating and melting stage; if the temperature in the crucible 3 reaches the melting point of the growth raw materials and remains for the first preset duration, it is determined to be in the crystallization stage; if the temperature in the crucible 3 continues to drop for the second preset duration, it is determined to be in the cooling stage.

[0035] If the current crystal growth stage is the heating and melting stage, then the product of the first coefficient and the value of the alternating current is used as the value of the compensation current, and the direction opposite to the direction of the alternating current is used as the direction of the compensation current, where the first coefficient is greater than 1; if the current crystal growth stage is the cooling stage, then the product of the second coefficient and the value of the alternating current is used as the value of the compensation current, where the second coefficient is greater than or equal to 0 and less than 1.

[0036] Exemplarily, the first coefficient k1 is 1.2, and the second coefficient k2 is 0.8. When it is determined to be the heating and melting stage, the value of the compensation current is k1*I, where I is the value of the alternating current. If I is 10 A, it is 12 A; when it is determined to be the cooling stage, the value of the compensation current is k2*I, which is 8 A.

[0037] Specifically, in the heating and melting stage, rapid heating is required to change the growth raw material from solid state to liquid state. During the heating process, a large induced magnetic field interference may be generated. And in order to accelerate the heating rate, by passing a compensation current stronger than the alternating current and in the opposite direction through the compensation coil 5, the induced magnetic field interference can be more effectively cancelled, and at the same time, the heating magnetic field can be strengthened, so that the raw material can absorb heat faster to reach the melting point, thereby optimizing the energy efficiency. At the same time, in the cooling stage, the crystal has basically grown, and slow cooling is required to ensure the quality of the crystal. By passing a relatively small compensation current through the compensation coil 5, on the one hand, the induced magnetic field interference can continue to be cancelled, and on the other hand, the magnetic field environment during the cooling process can be finely adjusted to avoid affecting the crystal structure due to sudden changes in the magnetic field. The relatively small compensation current can maintain a relatively stable magnetic field environment to a certain extent, preventing stress or defects from being generated inside the crystal due to sudden changes in the magnetic field during the cooling process.

[0038] Further, after obtaining the current crystal growth stage, the following steps are further included: If the current crystal growth stage is the crystallization stage, the temperature gradient and the magnetic field gradient are obtained in real time, and based on the temperature gradient, the magnetic field gradient, and the alternating current information, the compensation current information is obtained; the temperature gradient is the temperature difference at different positions in the crucible 3, and the magnetic field gradient is the magnetic field strength difference at different positions in the furnace body 1.

[0039] Specifically, a plurality of temperature sensors are arranged at different positions in the crucible 3 to accurately measure the temperature distribution in the crucible 3. The installation of the sensors needs to ensure that their probes can accurately contact or be close to the growth raw materials in the crucible 3 to accurately measure the temperature of the raw materials. For example, temperature sensors can be arranged at different height positions along the wall of the crucible 3, or a plurality of temperature sensors can be circumferentially arrayed along the transverse center line of the crucible 3. For a typical cylindrical crucible 3, temperature sensors can be arranged at a certain interval (such as one every 5 cm along the height direction) to form a temperature sensor network. The temperature gradient can be represented by a one-dimensional temperature gradient or a multi-dimensional temperature gradient. The one-dimensional temperature gradient is the ratio of the temperature reading difference between two temperature sensors to the distance between the two temperature sensors, and the multi-dimensional temperature gradient is calculated using partial derivatives.

[0040] Specifically, for the furnace body 1, a plurality of magnetic field sensors are circumferentially arrayed along the transverse center line of the crucible 3 to form a three-dimensional magnetic field sensor array. For example, a sensor is arranged at different radius positions (such as 5 cm, 10 cm, 15 cm, etc. from the central axis), and the calculation method of the magnetic field gradient is the same as that of the temperature gradient.

[0041] Further, obtaining the compensation current information according to the temperature gradient, the magnetic field gradient, and the alternating current information specifically includes the following steps: Retrieve and traverse the marginal benefit database to obtain alternative current information corresponding to the growth parameter combination corresponding to the temperature gradient, the magnetic field gradient, and the alternating current information, and use the alternative current information as the compensation current information; Wherein, the marginal benefit database includes multiple groups of growth parameter combinations and alternative current information corresponding to each group of the growth parameter combinations. The growth parameter combination is a combination formed by a preset temperature gradient, a preset magnetic field gradient, and preset alternating current information. The alternative current information is the current information that maximizes the marginal benefit under the growth parameter combination, and the marginal benefit is comprehensively obtained from the crystal furnace energy efficiency index and the crystal growth quality index.

[0042] Further, the method further includes constructing the marginal benefit database; the constructing the marginal benefit database specifically includes the following steps: Obtain a finite element model corresponding to the crystal furnace and a test sample set. The test sample set includes multiple groups of the growth parameter combinations and multiple test current information corresponding to each group of the growth parameter combinations; Input the combinations of the growth parameters of each group and the multiple test current information corresponding to each combination of the growth parameters into the finite element model in sequence, to obtain the marginal effect value corresponding to each test current information in each combination of the growth parameters, where the marginal effect value is obtained from the energy consumption and the crystal quality index, and the crystal quality index includes at least the dislocation density and the impurity content; Use the test current information with the maximum marginal effect value in the combination of the growth parameters as the alternative current information corresponding to this combination of the growth parameters, so as to obtain the marginal benefit database.

[0043] Specifically, use finite element analysis software (such as COMSOL Multiphysics) to construct a physical model corresponding to the crystal furnace. This model includes the main components of the crystal furnace, such as the furnace body 1, the crucible 3, the induction coil 4, the compensation coil 5, etc. At the same time, material properties (such as conductivity, permeability, thermal conductivity, etc.) and their interactions need to be considered. Obtain the test sample set through experimental design or historical data collection, and determine multiple combinations of growth parameters. For example, preset different temperature gradient ranges (such as 0.1 - 1.0 °C / mm), magnetic field gradient ranges (such as 0.01 - 0.1 T / mm), and alternating current information ranges (such as 10 - 100 A). For each combination of growth parameters, set multiple test current information (such as under a certain combination of growth parameters, the test current information can be 10 A, 20 A, 30 A, etc.), and input each combination of growth parameters and the corresponding test current information into the finite element model. The finite element model will calculate crystal quality indexes such as energy consumption, dislocation density, and impurity content under different conditions according to physical principles such as electromagnetics and heat conduction. The marginal effect value comprehensively considers the energy consumption and the crystal quality index. By calculating the reciprocal of the energy consumption (the lower the energy consumption, the better) and combining the crystal quality index (the lower the dislocation density and the impurity content, the better), find a test current information with the optimal comprehensive performance as the alternative current information.

[0044] Exemplarily, the following combinations of growth parameters are set: temperature gradient range: 0.1 - 1.0 °C / mm, magnetic field gradient range: 0.01 - 0.1 T / mm, alternating current information range: 10 - 100 A. For a specific set of growth parameter combinations, such as a temperature gradient of 0.5 °C / mm, a magnetic field gradient of 0.05 T / mm, and an alternating current information of 30 A, simulations are performed for multiple test current information: When the test current information is 20 A, the simulation results are an energy consumption of 1000 J, a dislocation density of 0.1, and an impurity content of 0.05. When the test current information is 30 A, the simulation results are an energy consumption of 800 J, a dislocation density of 0.08, and an impurity content of 0.03. When the test current information is 40 A, the simulation results are an energy consumption of 900 J, a dislocation density of 0.05, and an impurity content of 0.02. Calculate the marginal effect value: For 20 A: Marginal effect value = (1 / 1000) * ((1 - 0.1) * 0.5 + (1 - 0.05) * 0.5) = 0.000425. For 30 A: Marginal effect value = (1 / 800) * ((1 - 0.08) * 0.5 + (1 - 0.03) * 0.5) = 0.00057875. For 40 A: Marginal effect value = (1 / 900) * ((1 - 0.05) * 0.5 + (1 - 0.02) * 0.5) = 0.00053889. Select 30 A as the alternative current information for this set of growth parameter combinations and store it in the database. During the crystal growth process, when it is real-time monitored that the temperature gradient is 0.5 °C / mm, the magnetic field gradient is 0.05 T / mm, and the alternating current information is 30 A, the compensated current information of 40 A is queried from the database and input into the compensation coil 5 to optimize the crystal growth.

[0045] In a preferred embodiment, the compensation coil 5 is formed by connecting a plurality of sub-coils, and each of the sub-coils is connected in parallel to the same compensation power supply; the induced magnetic field intensity is obtained from the point magnetic field intensities read at multiple positions corresponding to the orientations of the respective sub-coils; Specifically, each sub-coil can be a plurality of coils divided along the height direction of the crucible 3. In this scenario, each sub-coil is circular, or it can be a plurality of coils separated along the circumferential direction of the crucible 3. In this scenario, each sub-coil is fan-shaped. Each sub-coil is connected in parallel to the same compensation power supply to ensure that they are in a parallel state in the circuit. In this way, the voltage across each sub-coil is equal, and the current will be distributed according to the characteristics such as the resistance of the sub-coil. A magnetic field sensor is installed at the center position of each sub-coil.

[0046] Before obtaining the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field in real time, the following steps are further included: Obtain the magnetic field intensity at the position readings corresponding to the orientations of the respective sub-coils, and obtain the average value of the first position magnetic field intensity; Judge whether the differences between all the position magnetic field intensities and the average value of the first position magnetic field intensity are all less than a first preset deviation; Obtaining the induced magnetic field information of the induced magnetic field includes the following steps: If so, use the average value of the first position magnetic field intensity as the induced magnetic field intensity.

[0047] Specifically, in this case, it shows that the magnetic field intensities at each position are relatively uniform. Within the allowable deviation range, the average value can be directly taken as the overall induced magnetic field intensity.

[0048] In a preferred embodiment, each of the sub-coils has an adjustable resistor connected in series therewith; After judging whether the differences between all the position magnetic field intensities and the average value of the position magnetic field intensity are all less than the first preset deviation, the following steps are further included: If not, take the sub-coil corresponding to the position where the magnetic field intensity with a difference greater than or equal to the first preset deviation from the average value of the first position magnetic field intensity as the target sub-coil; Use the average value of the second position magnetic field intensity of the sub-coils other than the target sub-coil as the induced magnetic field intensity; Based on the average value of the second position magnetic field intensity and the magnetic field intensity at the position corresponding to the target sub-coil, obtain an adjustment resistance value; Adjust the adjustable resistor connected in series with the target sub-coil with the adjustment resistance value to optimize the magnetic field distribution in the crystal furnace.

[0049] Specifically, the goal of obtaining the adjustment resistance value is to optimize the magnetic field distribution by adjusting the adjustable resistor connected in series with the target sub-coil, so that the magnetic field intensity at the position where the target sub-coil is located is close to the average value of the second position magnetic field intensity. After obtaining the adjustment resistance value, it needs to be applied to the adjustable resistor connected in series with the target sub-coil. For an actual adjustable resistor, it can be a potentiometer or a digital adjustable resistor. The specific adjustment method depends on the type of resistor used. If it is a potentiometer, the resistance value can be changed by mechanical rotation or electronic control. For example, for a mechanical potentiometer, a motor can be used to drive the rotating shaft to rotate a certain angle, and this angle can be converted according to the resistance adjustment characteristics of the potentiometer and the adjustment resistance value. If it is a digital adjustable resistor (such as a digital potentiometer using the I²C or SPI interface), the resistance value can be adjusted to the original resistance plus the adjustment resistance value by sending corresponding control commands to it.

[0050] Specifically, an implementation manner of calculating the adjusted resistance value is given. If the average magnetic field intensity at the second point is , the initial resistance of the adjustable resistor connected in series with each sub-coil is , the original magnetic field intensity generated by a sub-coil is , where B is the initial magnetic field intensity of the sub-coil, k is a coefficient related to the coil structure and physical constants, N is the number of turns of the coil, and I is the current passing through the coil. Therefore, formula one is obtained , and the target sub-coil after adjustment should satisfy formula two . Substituting formula one into formula two gives: , where is the target resistance value. Therefore , so the adjusted resistance value . After adjusting the resistance value of the adjustable resistor on the target sub-coil, the magnetic field intensity generated by this sub-coil will also change, thereby optimizing the magnetic field distribution in the crystal furnace and making the overall magnetic field distribution more uniform.

[0051] Based on the structure of the compensation coil 5, obtaining the compensation current information according to the temperature gradient, the magnetic field gradient, and the alternating current information specifically includes the following steps: Obtain the temperature gradient and the magnetic field gradient corresponding to each of the sub-coils; According to the temperature gradient, the magnetic field gradient, and the alternating current information corresponding to each of the sub-coils, obtain the regional current information of each of the sub-coils; According to the regional current information of each of the sub-coils, obtain the first adjustable resistance value of each of the sub-coils; all the first adjustable resistance values form the compensation current information.

[0052] In a preferred embodiment, the induced magnetic field information further includes the induced magnetic field change rate; After the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field are obtained in real time, the following steps are further included: If the induced magnetic field intensity is less than or equal to a first preset intensity and the induced magnetic field change rate is less than or equal to a first preset change rate, turn off the compensation power supply and obtain the current crystal growth stage; Specifically, when the induced magnetic field intensity is less than or equal to the first preset intensity and the induced magnetic field change rate is less than or equal to the first preset change rate, it is considered that the current induced magnetic field is weak enough and its change rate is also small enough, and the compensation power supply no longer needs to work to save energy or avoid unnecessary influences.

[0053] If the current crystal growth stage is the heating and melting stage, retrieve the preset heating curve, increase the heating temperature corresponding to the next heating moment adjacent to the current moment to obtain an updated heating curve; the preset heating curve is a curve composed of the heating temperatures corresponding to each heating moment within the heating and melting stage.

[0054] Specifically, the heating temperature corresponding to the next heating moment adjacent to the current moment will be increased, thereby obtaining an updated heating curve. This means that when the above-mentioned induced magnetic field conditions are met, the temperature planning for the heating and melting stage will be adjusted, which can accelerate the heating and melting process and accelerate the crystal growth process while ensuring the crystal quality.

[0055] Further, the step of increasing the heating temperature corresponding to the next heating moment adjacent to the current moment to obtain an updated heating curve specifically includes the following steps: Calculate the first target temperature, obtain the index of the current moment in the preset heating curve, and determine the index of the next heating moment adjacent to the current moment; Specifically, calculate the first target temperature through a temperature calculation model. The inputs of the temperature calculation model are crystal type, current temperature, heating power, and thermal field distribution information, and the output is the first target temperature.

[0056] Exclude the original heating temperature of the next heating moment adjacent to the current moment, calculate the absolute value of the difference between the other original heating temperatures and the first target temperature, and find the original heating temperature closest to it as the second target temperature; the heating moment corresponding to the closest original heating temperature is the target heating moment; Update the original heating temperature of the next heating moment adjacent to the current moment to the second target temperature, and shift the part of the preset heating curve after the target heating moment forward according to the time interval to obtain an updated heating curve.

[0057] Exemplarily, assume that the original heating curve is [(0, 100), (10, 200), (20, 300), (30, 400), (40, 500), (50, 600), (60, 700), (70, 800)], the current time is 20 minutes, and the first target temperature is 430 degrees. The original temperature closest to 430 degrees is 400 degrees at 30 minutes. Therefore, the updated heating curve will be [(0, 100), (10, 200), (20, 400), (30, 500), (40, 600), (50, 700), (60, 800)]. Update the heating temperature at 20 minutes to 400, and shift the curve after 20 minutes forward by 10 minutes. Without changing the final temperature reached, shortening the time means that more heat needs to be provided per unit time, thus accelerating the conversion rate of the growth raw material from solid state to liquid state, improving the heating efficiency, effectively shortening the duration of the heating and melting stage, and optimizing the energy efficiency of the crystal furnace. Moreover, when adjusting the heating curve, although the overall process is accelerated, when shifting the heating curve, the first temperature gradient between the second target temperature and the previous temperature is ensured to be less than the preset temperature gradient, so that the local physical and chemical equilibrium can still be maintained, ensuring that the subsequent crystal growth quality will not be adversely affected.

[0058] Embodiment 2 Based on Embodiment 1, this embodiment proposes an energy efficiency optimization control system for a crystal furnace, which is used to implement the energy efficiency optimization control method for a crystal furnace as described in Embodiment 1; it includes the following steps: A collection module, which is configured to, after receiving the first start signal of the induction heating power supply, acquire the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field in real time; the alternating current information includes the alternating current value and the alternating current direction, and the induced magnetic field information includes the induced magnetic field intensity; A judgment module, which is configured to, if the induced magnetic field intensity is greater than the first preset intensity, obtain the corresponding compensation current information according to the alternating current information, and the compensation current information includes the compensation current value and the compensation current direction of the compensation current; wherein, the compensation current corresponding to the compensation current information can cancel the interference of the induced magnetic field on the heating magnetic field; A control module, which is configured to send the compensation current information to the power drive module to input the compensation current corresponding to the compensation current information into the compensation coil 5.

[0059] In this text, specific examples are used to illustrate the principles and implementation manners of the present application. The description of the above embodiments is only for helping to understand the method and its core idea of the present application. The above description is only the preferred implementation manner of the present application. It should be noted that due to the limited nature of written expression and objectively infinite specific structures, for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements, embellishments or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, embellishments, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, shall all be regarded as the protection scope of the present application.

Claims

1. A method for optimizing the energy efficiency of a crystal furnace, characterized in that: Crystal furnace includes: A furnace body (1), wherein the furnace body (1) has a growth space therein, a support assembly (6) is provided in the growth space and at the bottom of the furnace body (1), and a crucible (3) for accommodating growth raw materials is provided on the support assembly (6); A heating component, the heating component comprising an induction coil (4) arranged around the outer periphery of the crucible (3), the induction coil (4) being connected to an induction heating power supply, the induction heating power supply being used to provide an alternating current to the induction coil (4), the alternating magnetic field formed by the alternating current being used as a heating magnetic field for the growing raw material; a compensation coil (5), the compensation coil (5) being arranged on a side of the induction coil (4) close to the crucible (3), the compensation coil (5) being connected to a compensation power supply, the compensation power supply comprising a power drive module, the power drive module being used to adjust a compensation current input to the compensation coil (5); A monitoring component, the monitoring component being arranged around the crucible (3) and used for monitoring an induced magnetic field in the crucible (3), the induced magnetic field being formed by strong eddy currents generated in the crucible (3) under the action of the alternating magnetic field generated by the induction coil (4) after an alternating current is passed through the induction coil (4); The control method comprises the following steps: After receiving the first start signal of the induction heating power supply, the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field are acquired in real time; the alternating current information includes the alternating current value and the alternating current direction, and the induced magnetic field information includes the induced magnetic field intensity; If the induced magnetic field strength is greater than the first preset strength, corresponding compensation current information is obtained according to the alternating current information, wherein the compensation current information includes a compensation current value and a compensation current direction of the compensation current; wherein the compensation current corresponding to the compensation current information can offset the interference of the induced magnetic field on the heating magnetic field; The compensation current information is sent to the power driving module, so that the compensation current corresponding to the compensation current information is input into the compensation coil (5).

2. The energy efficiency optimization control method for a crystal furnace according to claim 1, characterized in that: The value of the compensation current is the same as the value of the alternating current, and the direction of the compensation current is opposite to the direction of the alternating current.

3. The energy efficiency optimization control method for a crystal furnace according to claim 1, characterized in that: The step of obtaining the compensation current information according to the alternating current information specifically includes the following steps: Obtaining the current crystal growth stage, wherein the crystal growth stage includes a heating and melting stage, a crystallization stage, and a cooling stage; If the current crystal growth stage is the heating and melting stage, the product of the first coefficient and the alternating current value is used as the compensation current value, and the direction opposite to the alternating current direction is used as the compensation current direction, and the first coefficient is greater than 1; if the current crystal growth stage is the cooling stage, the product of the second coefficient and the alternating current value is used as the compensation current value, and the second coefficient is greater than or equal to 0 and less than 1.

4. The energy efficiency optimization control method for a crystal furnace according to claim 3, characterized in that: After obtaining the current crystal growth stage, the following steps are also included: If the current crystal growth stage is the crystallization stage, the temperature gradient and the magnetic field gradient are acquired in real time, and the compensation current information is obtained based on the temperature gradient, the magnetic field gradient and the alternating current information; the temperature gradient is the temperature difference at different positions in the crucible (3), and the magnetic field gradient is the magnetic field intensity difference at different positions in the furnace body (1).

5. The energy efficiency optimization control method for a crystal furnace according to claim 4, characterized in that: The step of obtaining the compensation current information according to the temperature gradient, the magnetic field gradient and the alternating current information specifically includes the following steps: Retrieving and traversing a marginal benefit database to obtain candidate current information corresponding to a growth parameter combination corresponding to the temperature gradient, the magnetic field gradient, and the alternating current information, and using the candidate current information as the compensation current information; Among them, the marginal benefit database includes multiple groups of growth parameter combinations and alternative current information corresponding to each group of the growth parameter combinations, the growth parameter combination is a combination formed by a preset temperature gradient, a preset magnetic field gradient and a preset alternating current information, the alternative current information is the current information that maximizes the marginal benefit under the growth parameter combination, and the marginal benefit is obtained by combining the crystal furnace energy efficiency index and the crystal growth quality index.

6. The energy efficiency optimization control method for a crystal furnace according to claim 5, characterized in that: The method further includes constructing the marginal benefit database; the constructing the marginal benefit database specifically includes the following steps: Acquire a finite element model and an experimental sample set corresponding to the crystal furnace, wherein the experimental sample set includes a plurality of groups of growth parameter combinations and a plurality of experimental current information corresponding to each group of growth parameter combinations; Inputting each group of the growth parameter combination and a plurality of test current information corresponding to each group of the growth parameter combination into the finite element model in sequence, obtaining a marginal effect value corresponding to each of the test current information in each group of the growth parameter combination, wherein the marginal effect value is obtained from energy consumption and crystal quality index, and the crystal quality index at least includes dislocation density and impurity content; The test current information having the maximum marginal effect value in the growth parameter combination is used as the candidate current information corresponding to the group of growth parameter combinations to obtain the marginal benefit database.

7. The energy efficiency optimization control method for a crystal furnace according to claim 6, characterized in that: The compensation coil (5) is formed by a plurality of interconnected sub-coils, each of which is connected in parallel to the same compensation power supply; the induced magnetic field strength is obtained by reading the magnetic field strength at a plurality of points corresponding to the positions of each of the sub-coils; Before the real-time acquisition of the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field, the following steps are also included: Obtaining the magnetic field strength at the point corresponding to the position of each sub-coil, and obtaining the average value of the magnetic field strength at the first point; Determine whether the difference between the magnetic field strength at all the points and the average value of the magnetic field strength at the first point is less than a first preset deviation; Acquiring the induced magnetic field information of the induced magnetic field comprises the following steps: If so, the average value of the magnetic field strength at the first point is used as the induced magnetic field strength.

8. The energy efficiency optimization control method for a crystal furnace according to claim 7, characterized in that: Each of the sub-coils has an adjustable resistor connected in series therewith; After determining whether the differences between the magnetic field strengths at all the points and the average value of the magnetic field strengths at the points are all less than the first preset deviation, the following steps are also included: If not, taking the sub-coil at the position corresponding to the magnetic field strength of the point whose difference with the average magnetic field strength of the first point is greater than or equal to the first preset deviation as the target sub-coil; Taking the average value of the magnetic field strength at the second point of the sub-coil except the target sub-coil as the induced magnetic field strength; Based on the average value of the magnetic field strength at the second point and the magnetic field strength at the point corresponding to the orientation of the target sub-coil, an adjustment resistance value is obtained; The adjustable resistor connected in series with the target sub-coil is adjusted according to the adjustment resistance value to optimize the magnetic field distribution in the crystal furnace.

9. The energy efficiency optimization control method for a crystal furnace according to claim 1, characterized in that: The induced magnetic field information also includes the induced magnetic field change rate; After the real-time acquisition of the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field, the following steps are also included: If the induced magnetic field strength is less than or equal to the first preset strength, and the induced magnetic field change rate is less than or equal to the first preset change rate, then turning off the compensation power supply and obtaining the current crystal growth stage; If the current crystal growth stage is the heating and melting stage, the preset heating curve is called up to increase the heating temperature corresponding to the next heating moment adjacent to the current moment to obtain an updated heating curve; the preset heating curve is a curve composed of the heating temperatures corresponding to each heating moment in the heating and melting stage.

10. An energy efficiency optimization control system for a crystal furnace, used to implement the energy efficiency optimization control method for a crystal furnace as described in any one of claims 1 to 9; characterized in that: The following steps are involved: A collection module, wherein the collection module is configured to obtain, in real time, the alternating current information of the alternating current and the induced magnetic field information of the induced magnetic field after receiving the first start signal of the induction heating power supply; the alternating current information includes the alternating current value and the alternating current direction, and the induced magnetic field information includes the induced magnetic field intensity; A judgment module, wherein the judgment module is configured to obtain corresponding compensation current information according to the alternating current information if the induced magnetic field strength is greater than a first preset strength, wherein the compensation current information includes a compensation current value and a compensation current direction of the compensation current; wherein the compensation current corresponding to the compensation current information can offset the interference of the induced magnetic field on the heating magnetic field; A control module, the control module being configured to send the compensation current information to the power driving module, so as to input the compensation current corresponding to the compensation current information into the compensation coil (5).

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