Parallel vacuum sintering control system

Abstract

This invention discloses a parallel vacuum sintering control system, relating to the field of sintering furnace technology. The parallel vacuum sintering control system includes a furnace body, a vacuum pump, a furnace temperature controller, and multiple heating containers. Each heating container is located in a hollow common cavity inside the furnace body, and each heating container has a heating chamber surrounded by insulating material, which is connected to the common cavity. The vacuum pump is used to create a vacuum environment in the common cavity. Each heating container's heating chamber is equipped with a heater and a temperature acquisition device. The furnace temperature controller is connected to the heater and temperature acquisition device of each heating container. The furnace temperature controller acquires the temperature setpoint for each heating container and, based on the difference between the actual temperature value acquired by the temperature acquisition device within the heating container and the temperature setpoint, controls the heating power of the heater within the heating container to make the actual temperature value of the heating container approach the temperature setpoint. This solution can improve the efficiency of rare earth vacuum sintering experiments.

Description

Technical Field

[0001] This invention relates to the field of sintering furnace technology, and in particular to a parallel vacuum sintering control system. Background Technology

[0002] Currently, the sintering technology of magnetic materials in China has reached a relatively high level. However, with the increasing scarcity of rare earth resources, how to improve the utilization efficiency of rare earth elements while ensuring or even improving product performance has become an important issue in the field of materials research and development. To this end, researchers need to conduct vacuum sintering experiments on rare earths to systematically investigate the influence of different sintering temperatures on material properties under the same vacuum or atmospheric conditions, in order to optimize process parameters.

[0003] Currently, existing industrial vacuum sintering furnaces typically employ a single-chamber structure, allowing sintering experiments to be conducted only at a uniform temperature. If sintering experiments at multiple temperatures under the same vacuum level are required, they must be performed in batches. This not only prolongs the experimental cycle but also leads to low efficiency in sintering experiments, significantly impacting the efficiency of vacuum sintering experiments for rare earth materials. Summary of the Invention

[0004] In view of this, this application provides a parallel vacuum sintering control system, the main purpose of which is to solve the technical problem of low efficiency in vacuum sintering experiments on rare earths.

[0005] According to a first aspect of the present invention, a parallel vacuum sintering control system is provided, the parallel vacuum sintering control system comprising a furnace body, a vacuum pump, a furnace temperature controller, and multiple heating containers;

[0006] Each of the heating containers is disposed in a hollow common cavity inside the furnace body. Each heating container has a heating cavity surrounded by heat-insulating material for holding the material to be heated. A through hole is provided on one side of the heating container so that the heating cavity of the heating container communicates with the common cavity.

[0007] The air inlet of the vacuum pump is connected to the common cavity and is used to extract gas from the common cavity to create a vacuum environment in the common cavity.

[0008] Each of the heating containers is equipped with a heater and a temperature acquisition device in its heating chamber, and the furnace temperature controller is connected to the heater and temperature acquisition device of each of the heating containers.

[0009] The furnace temperature controller is used to acquire the temperature setpoint corresponding to each of the heating containers, and to control the heating power of the heater in the heating container based on the difference between the actual temperature value collected by the temperature acquisition device in the heating container and the temperature setpoint, so that the actual temperature value of the heating container approaches the temperature setpoint.

[0010] In an optional embodiment, the furnace temperature controller includes a central controller and multiple temperature controllers, each corresponding to one of the heating containers. The central controller acquires a temperature setpoint for each heating container and sends the setpoint to the corresponding temperature controller. Each temperature controller is connected to a heater and a temperature collector within one of the heating containers. It acquires the setpoint, acquires the actual temperature value collected by the temperature collector in real time, and controls the heating power of the heater based on the temperature difference between the actual temperature value and the setpoint, so that the actual temperature value inside the heating chamber of the heating container approaches the setpoint.

[0011] In an optional embodiment, the temperature controller obtains the temperature setpoint by: obtaining a temperature value curve, wherein the horizontal axis of the temperature value curve is time and the vertical axis of the temperature value curve is temperature value; determining the current time point, and determining the temperature value corresponding to the time point in the temperature value curve based on the time point, and determining the temperature value as the temperature setpoint.

[0012] In an optional embodiment, the heating chamber of the heating container includes a front heating chamber and a rear heating chamber that communicate with each other; the heater inside the heating container includes two sub-heaters, each sub-heater being a first sub-heater and a second sub-heater, the first sub-heater being disposed in the front heating chamber and the second sub-heater being disposed in the rear heating chamber; the temperature acquisition device inside the heating container includes a front temperature acquisition device and a rear temperature acquisition device, the front temperature acquisition device being used to acquire the actual temperature value of the front heating chamber and the rear temperature acquisition device being used to acquire the actual temperature value of the rear heating chamber; the temperature controller includes two sub-temperature controllers, each sub-temperature controller being a first sub-temperature controller. The device comprises a first sub-temperature controller and a second sub-temperature controller. The first sub-temperature controller is used to acquire the temperature setpoint and acquire the actual temperature value collected by the front temperature collector in real time. Based on the temperature difference between the actual temperature value and the temperature setpoint, the controller controls the heating power of the first sub-heater so that the actual temperature value of the front heating chamber of the heating container approaches the temperature setpoint. The second sub-temperature controller is used to acquire the temperature setpoint and acquire the actual temperature value collected by the rear temperature collector in real time. Based on the temperature difference between the actual temperature value and the temperature setpoint, the controller controls the heating power of the second sub-heater so that the actual temperature value of the rear heating chamber of the heating container approaches the temperature setpoint.

[0013] In an optional embodiment, the sub-temperature controller is configured to perform the following processes: the sub-temperature controller acquires the temperature setpoint and the actual temperature value; calculates the temperature difference between the temperature setpoint and the actual temperature value, and performs PID adjustment on the temperature difference to obtain a power indication signal; and sends the power indication signal to the sub-heater to control the heating power of the sub-heater.

[0014] In an optional embodiment, each of the sub-heaters includes a voltage regulator and a heating unit; the voltage regulator is connected to the sub-temperature controller, an external power supply, and the heating unit respectively, and is used to receive a power supply voltage of a preset voltage value from the external power supply and to supply power to the heating unit; the voltage regulator is also used to receive the power indication signal, and to perform voltage conversion on the power supply voltage based on the power indication signal to obtain a supply voltage, and to supply power to the heating unit through the supply voltage.

[0015] In an optional embodiment, the power indication signal is a current signal; the voltage regulator performs voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage, including: determining the current value of the current signal and determining a current ratio between the current value and a preset current value; proportionally reducing the voltage value of the power supply voltage based on the current ratio to obtain the supply voltage, such that the voltage ratio between the supply voltage and the power supply voltage is equal to the current ratio; and supplying power to the heating unit through the supply voltage.

[0016] In an optional embodiment, the power indication signal is a pulse width modulation signal; the method by which the voltage regulator performs voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage further includes: determining the duty cycle value of the pulse width modulation signal; proportionally reducing the voltage value of the power supply voltage based on the duty cycle value to obtain the supply voltage, such that the voltage ratio between the supply voltage value and the power supply voltage value is equal to the duty cycle value; and supplying power to the heating unit through the supply voltage.

[0017] In an optional embodiment, the front temperature acquisition unit includes a front temperature sensor, a first local temperature sensor, and multiple second local temperature sensors; wherein, the front temperature sensor is used to acquire the central temperature value of the front heating cavity, the first local temperature sensor is disposed at the junction of the front heating cavity and the rear heating cavity, and is used to acquire a first local temperature value, and each second local temperature sensor is disposed at a different position at the end of the front heating cavity away from the rear heating cavity, and is used to acquire a second local temperature value at a different position; the first sub-temperature controller is connected to the front temperature sensor and the first local temperature sensor respectively. The device is connected to each of the second local temperature sensors to obtain the central temperature value, the first local temperature value, and the second local temperature value. The method by which the first sub-temperature controller obtains the actual temperature value collected by the front temperature sensor in real time includes: determining whether the first local temperature value is equal to the temperature setpoint; if the first local temperature value is equal to the temperature setpoint, calculating the second local temperature average of all the second local temperature values, and calculating the temperature difference between the second local temperature average and the temperature setpoint; compensating the central temperature value based on the temperature difference to obtain the actual temperature value.

[0018] In an optional embodiment, the rear temperature acquisition unit includes a rear temperature sensor, a third local temperature sensor, and multiple fourth local temperature sensors; wherein, the rear temperature sensor is used to acquire the central temperature value of the rear heating cavity, the third local temperature sensor is disposed at the junction of the front heating cavity and the rear heating cavity, and is used to acquire a third local temperature value, and each of the fourth local temperature sensors is disposed at a different position at the end of the rear heating cavity away from the front heating cavity, and is used to acquire fourth local temperature values ​​at different positions; the second sub-temperature controller is connected to the rear temperature sensor and the third local temperature sensor respectively. The device and each of the fourth local temperature sensors are connected to obtain the central temperature value, the third local temperature value, and the fourth local temperature value; the second sub-temperature controller obtains the actual temperature value collected by the rear temperature acquisition device in real time by: determining whether the third local temperature value is equal to the temperature set value; if the third local temperature value is equal to the temperature set value, calculating the fourth local temperature average of all the fourth local temperature values, and calculating the temperature difference between the fourth local temperature average and the temperature set value; correcting the central temperature value based on the temperature difference value to obtain the actual temperature value.

[0019] This invention provides a parallel vacuum sintering control system that enables simultaneous experiments at multiple different sintering temperatures under the same vacuum or atmosphere environment. This solves the problem of conventional equipment being unable to compare the temperatures of multiple processes in the same environment, significantly improving R&D efficiency and the comparability of experimental data. Specifically, by setting up multiple independent heating containers side-by-side in a common cavity and sharing a single vacuum pump system, not only is the vacuum or atmosphere condition of each temperature zone highly consistent, but the utilization rate of the vacuum unit is also improved, reducing equipment costs and maintenance expenses. Each heating container is enclosed by insulating material, has a small heat capacity, requires less loading, has a fast heating response, and low energy consumption, making it suitable for small-batch, multi-parameter process exploration, effectively reducing the consumption of valuable rare earth materials. Furthermore, each heating cavity is equipped with a heater and a temperature acquisition device. The furnace temperature controller independently adjusts the power of each heater based on the difference between the acquired actual temperature and the set value, achieving precise closed-loop temperature control. This ensures that the actual temperature of each temperature zone stably approaches the set value, resulting in high temperature control accuracy and good temperature uniformity, greatly improving the efficiency of vacuum sintering experiments on rare earths.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 A schematic diagram of a parallel vacuum sintering control system provided in an embodiment of the present invention is shown;

[0023] Figure 2 A schematic diagram of a furnace temperature controller provided in an embodiment of the present invention is shown;

[0024] Figure 3 A schematic diagram of a heating cavity provided in an embodiment of the present invention is shown;

[0025] Figure 4 A schematic diagram of another parallel vacuum sintering control system provided in an embodiment of the present invention is shown;

[0026] Figure 5 The diagram illustrates a logic diagram of a sub-temperature controller generating a power indication signal according to an embodiment of the present invention.

[0027] Figure 6 A schematic diagram of a sub-heater provided in an embodiment of the present invention is shown;

[0028] Figure 7 This diagram illustrates one of the configurations of a temperature sensor in a heating cavity according to an embodiment of the present invention.

[0029] Figure 8 This is a second schematic diagram showing the arrangement of a temperature sensor in a heating chamber according to an embodiment of the present invention. Detailed Implementation

[0030] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present application can be combined with each other.

[0031] Currently, existing industrial vacuum sintering furnaces typically employ a single-chamber structure, allowing sintering experiments to be conducted only at a uniform temperature. If sintering experiments at multiple temperatures under the same vacuum level are required, they must be performed in batches. This not only prolongs the experimental cycle but also leads to low efficiency in sintering experiments, significantly impacting the efficiency of vacuum sintering experiments for rare earth materials.

[0032] To address the above problems, in one embodiment, such as Figure 1 As shown, a parallel vacuum sintering control system is provided. Taking the application of this system in vacuum sintering experiments on rare earths as an example, the parallel vacuum sintering control system includes a furnace body 100, a vacuum pump 200, a furnace temperature controller 300, and multiple heating containers 400. The furnace temperature controller 300 may include a serial port touch screen and a programmable logic controller (PLC). Relevant personnel can operate and control the programmable logic controller based on the serial port touch screen.

[0033] Specifically, each heating container 400 is disposed within a hollow common cavity 110 inside the furnace body 100. Each heating container 400 has a heating chamber 410, surrounded by heat-insulating material, for holding the material to be heated. One side of each heating container 400 has a through hole, while the other parts of the heating container 400 are closed, allowing the heating chamber 410 of the heating container 400 to communicate with the common cavity 110. The furnace body 100 may be equipped with a furnace door, which can be opened by personnel to place materials such as rare earth elements into the heating chamber 410 of the heating container 400. Furthermore, the furnace body 100 may be equipped with an exhaust valve, an inflation valve, and a deflation valve communicating with the common cavity 110, facilitating adjustment of the vacuum level in the common cavity 110.

[0034] Here, the heating container 400 can be a cuboid enclosed by heat-insulating material to reduce the mutual temperature influence between different heating containers 400. Furthermore, the heating container 400 can be fixed within the common cavity 110 by a support frame. The cuboid has a through-hole on the side facing the furnace door, allowing personnel to place rare earth elements into the heating container 400 through the through-hole. As an example, the number of heating containers 400 can be three, with each heating container 400 serving as a heating zone.

[0035] Furthermore, the air inlet of the vacuum pump 200 is connected to the common cavity 110 to extract gas from the common cavity 110, thereby creating a vacuum environment in the common cavity 110. Here, the vacuum pump 200 is used to evacuate the common cavity 110 to ensure that the rare earth elements in each heating container 400 are in the same vacuum level or atmosphere.

[0036] Furthermore, each of the heating containers 400 is provided with a heater 420 and a temperature acquisition device 430 in its heating chamber 410. The furnace temperature controller 300 is connected to the heater 420 and the temperature acquisition device 430 of each of the heating containers 400 to communicate with the heater 420 and the temperature acquisition device 430.

[0037] Furthermore, the furnace temperature controller 300 is used to acquire the temperature setpoint corresponding to each of the heating containers 400. Here, relevant personnel can input the temperature setpoint corresponding to each heating container 400 into the furnace temperature controller 300 via a serial port touchscreen. The furnace temperature controller 300 can also be connected to a remote computer terminal to acquire the temperature setpoint corresponding to each heating container 400 from the computer terminal. Here, the temperature setpoint can be the target temperature for the sintering experiment of rare earth elements.

[0038] Furthermore, the furnace temperature controller 300 is also used to control the heating power of the heater 420 in the heating container 400 based on the difference between the actual temperature value collected by the temperature acquisition device 430 in the heating container 400 and the temperature set value, so that the actual temperature value of the heating container 400 approaches the temperature set value.

[0039] Here, for each heating container 400, the furnace temperature controller 300 obtains the actual temperature value collected by the temperature acquisition device 430 of the heating container 400, subtracts the actual temperature value from the corresponding temperature setpoint of the heating container 400 to obtain the temperature difference, and performs PID regulation on the temperature difference. By calculating the deviation between the temperature setpoint and the actual temperature value in real time, the heating power is dynamically adjusted using the coordinated action of proportional (P), integral (I), and derivative (D) components to change the average power of the heater. When the actual temperature value is too low, the heating intensity is increased; when the actual temperature value is close to the setpoint, the heater power is reduced to avoid overheating of the material; when the actual temperature value is too high, the heater power is reduced or heating is stopped. This process is executed cyclically, so that the actual temperature in the heating chamber 410 of the heating container 400 quickly and smoothly approaches and stabilizes at the temperature setpoint, achieving high-precision temperature control.

[0040] Specifically, the heater 420 in each heating container 400 is connected to an external power source via a switching transistor to obtain electrical energy. During operation, for each heating container 400, the temperature acquisition device 430 collects the actual temperature value of its heating chamber 410 in real time. The furnace temperature controller 300 compares the actual temperature value with the preset temperature setpoint to obtain the temperature difference, and performs PID regulation on the difference to generate a pulse width modulation (PWM) signal with a specific duty cycle. Subsequently, the PWM signal is output to the control terminal of the switching transistor to control the switching transistor to periodically turn on and off: when the PWM signal is high, the switching transistor is on, and the heater 420 is powered on; when the PWM signal is low, the switching transistor is off, and the heater 420 is powered off. By adjusting the duty cycle of the PWM signal, the proportion of the energized time of the heater 420 per unit time is changed, thereby continuously adjusting its average heating power so that the actual temperature value of the heating container 400 dynamically approaches and stabilizes at the temperature setpoint.

[0041] The parallel vacuum sintering control system provided in this embodiment can simultaneously carry out multiple experiments at different sintering temperatures under the same vacuum or atmosphere environment, solving the problem that conventional equipment cannot achieve multi-process temperature comparison under the same environment, and improving the efficiency of vacuum sintering experiments on rare earths.

[0042] In an optional embodiment, such as Figure 2 As shown, the furnace temperature controller includes a central controller 310 and multiple temperature controllers 320, each of which corresponds to a heating container 400. Here, the central controller 310 can be a PLC device and may be equipped with a serial port touch screen. The temperature controllers 320 can be computer devices with certain computing capabilities.

[0043] Specifically, the central controller 310 is used to obtain the temperature setpoint corresponding to each of the heating containers 400 and send the temperature setpoint to the temperature controller 320 corresponding to the heating container 400.

[0044] Furthermore, the temperature controller 320 is connected to a heater (not shown in the figure) inside the heating container 400 and a temperature acquisition device (not shown in the figure) to obtain the temperature setpoint, and to obtain the actual temperature value collected by the temperature acquisition device in real time. Based on the temperature difference between the actual temperature value and the temperature setpoint, the heating power of the heater is controlled so that the actual temperature value of the heating chamber of the heating container 400 approaches the temperature setpoint.

[0045] The embodiments provided in this application enable temperature control of each heating container based on multiple temperature controllers, realizing centralized management and decentralized control of the multi-temperature zone sintering process. The central controller uniformly configures the temperature setpoints of each temperature zone, realizing centralized management of heating parameters, which facilitates operation and coordination. At the same time, each temperature controller corresponds one-to-one with the heating container, independently completing temperature acquisition, deviation calculation and heating power adjustment, ensuring fast temperature control response and high accuracy in each temperature zone.

[0046] In an optional embodiment, the temperature controller acquires the temperature setpoint by means of:

[0047] First, the temperature controller acquires a temperature value curve, wherein the horizontal axis of the temperature value curve represents time, and the vertical axis of the temperature value curve represents the temperature value.

[0048] Specifically, a set of temperature value curves can be set for each heating container, and the central controller sends the corresponding temperature value curves to the corresponding temperature controller. Here, relevant personnel can set the temperature value curves according to the production process requirements through the heating curve setting screen displayed on the serial port touch screen; furthermore, 20 different temperature value curves can be set for each heating container, and each temperature value curve can have temperature values ​​for multiple time periods.

[0049] Then, the current time point is determined, and the temperature value corresponding to the time point is determined in the temperature value curve based on the time point, and the temperature value is determined as the temperature setpoint.

[0050] Specifically, the temperature controller can determine the coordinate point corresponding to the current time point on the temperature value curve, determine the temperature value corresponding to that coordinate point, and then set that temperature value as the temperature setpoint. Here, when only one or two products are sintered, the temperature value curve can be reasonably edited, and one or two zones can be selected for heating rare earth elements to save energy.

[0051] The embodiments provided in this application achieve programmed temperature rise control by introducing a temperature-time curve, allowing the temperature setpoint to change dynamically over time, thus meeting the requirements of complex temperature rise and fall curves in the sintering process. Furthermore, the temperature controller can retrieve the real-time setpoint from a preset curve based on the current moment, enabling precise execution of process steps such as segmented temperature control and constant temperature maintenance, thereby improving the automation and accuracy of the temperature control process.

[0052] In an optional embodiment, such as Figure 3 As shown, each of the heating containers 400 has a heating chamber 410 including a front heating chamber 440 and a rear heating chamber 450 that are connected to each other; here, the front heating chamber 440 can be the area near the through hole 460, and the front heating chamber 440 and the rear heating chamber 450 are just spatial divisions of the heating chamber 410, and there are no physical dividing parts between them.

[0053] Furthermore, such as Figure 4 As shown, each of the heating containers includes two sub-heaters, namely a first sub-heater 421 and a second sub-heater 422. The first sub-heater 421 is disposed in the front heating chamber to heat the front heating chamber, and the second sub-heater 422 is disposed in the rear heating chamber to heat the rear heating chamber. Figure 4 The example uses three heating containers, but other numbers of heating containers are also applicable to this embodiment.

[0054] Furthermore, each of the heating containers includes a front temperature collector 431 and a rear temperature collector 432. The front temperature collector 431 is disposed in the front heating cavity and is used to collect the actual temperature value of the front heating cavity. The rear temperature collector 432 is disposed in the rear heating cavity and is used to collect the actual temperature value of the rear heating cavity.

[0055] Furthermore, the temperature controller includes two sub-temperature controllers, namely a first sub-temperature controller 321 and a second sub-temperature controller 322. Here, the first sub-temperature controller 321 is electrically connected to the central controller 310, the second sub-temperature controller 322, a first sub-heater 421 in a heating container, and a front temperature acquisition unit 431. The first sub-temperature controller 321 can obtain a temperature setpoint from the central controller 310 and send the temperature setpoint to the second sub-temperature controller 322. The first sub-temperature controller 321 and the second sub-temperature controller 322 can be temperature controllers, respectively.

[0056] Furthermore, the first sub-temperature controller 321 is used to acquire the temperature setpoint and acquire the actual temperature value collected by the front temperature collector 431 in real time, and control the heating power of the first sub-heater 421 according to the temperature difference between the actual temperature value and the temperature setpoint, so that the actual temperature value of the front heating chamber of the heating container approaches the temperature setpoint.

[0057] Here, the first sub-temperature controller 321 can obtain the temperature setpoint from the central controller 310 and the actual temperature value of the front heating chamber from the front temperature acquisition unit 431, and calculate the temperature difference between the temperature setpoint and the actual temperature value; further, the heating power of the first sub-heater 421 is controlled according to the temperature difference so that the actual temperature value of the front heating chamber of the heating container approaches the temperature setpoint.

[0058] Furthermore, the second sub-temperature controller 322 is used to acquire the temperature setpoint and acquire the actual temperature value collected by the rear temperature collector 432 in real time, and control the heating power of the second sub-heater 422 according to the temperature difference between the actual temperature value and the temperature setpoint, so that the actual temperature value of the rear heating chamber of the heating container approaches the temperature setpoint.

[0059] Here, the second sub-temperature controller 322 can obtain the temperature setpoint from the first sub-temperature controller 321 and obtain the actual temperature value of the rear heating chamber from the rear temperature acquisition unit 432 of the corresponding heating container, and calculate the temperature difference between the temperature setpoint and the actual temperature value; further, the heating power of the second sub-heater 422 is controlled according to the temperature difference so that the actual temperature value of the rear heating chamber of the heating container approaches the temperature setpoint.

[0060] The embodiments provided in this application achieve precise zoned control of the internal temperature field of the heating container by setting up front and rear dual heating chambers, dual heaters, and dual temperature acquisition devices within the heating container, and equipping it with independent sub-temperature controllers. This effectively improves the uniformity of the temperature zone, avoids local overheating or underheating, ensures consistent heating of the sample, and improves sintering quality and process reliability.

[0061] In an optional embodiment, the sub-temperature controller is configured to perform the following processes:

[0062] First, the sub-temperature controller acquires the temperature setpoint and the actual temperature value. Here, if the sub-temperature controller is a first sub-temperature controller corresponding to a heating container, then the sub-temperature controller can acquire the temperature setpoint corresponding to the heating container from the central controller and obtain the actual temperature value from the front temperature sensor inside the heating container; similarly, if the sub-temperature controller is a second sub-temperature controller corresponding to a heating container, then the sub-temperature controller can acquire the temperature setpoint corresponding to the heating container from the central controller and obtain the actual temperature value from the rear temperature sensor inside the heating container.

[0063] Then, the temperature difference between the setpoint and the actual temperature is calculated, and the temperature difference is adjusted using a PID controller to obtain a power indication signal; specifically, as shown... Figure 5 As shown, the sub-temperature controller acquires the temperature setpoint r(t) and subtracts the temperature setpoint r(t) from the real-time acquired actual temperature value PV to obtain the temperature difference e(t). Here, the temperature difference e(t) between the temperature setpoint r(t) and the real-time acquired actual temperature value PV can be calculated in real time, and the temperature difference e(t) is subjected to PID regulation, including proportional coefficient regulation using the proportional coefficient regulation module P, time integral regulation using the time integral module I, and differential time regulation using the differential time regulation module D. The results of the proportional coefficient regulation, time integral regulation, and differential time regulation are added together to obtain the real-time power indication signal u(t).

[0064] Here, the power indication signal u(t) output after PID regulation can be a physical quantity (such as a current signal) or a PWM signal with a specific duty cycle. The greater the temperature setpoint r(t) exceeds the actual temperature value PV, the higher the amplitude of the power indication signal u(t) and the larger its duty cycle. When the actual temperature value PV exceeds the temperature setpoint r(t), the sub-temperature controller C can cut off the power supply voltage to the sub-heater H.

[0065] Finally, the power indication signal u(t) is sent to the sub-heater H to control the heating power of the sub-heater H. Here, if the sub-temperature controller is a first sub-temperature controller corresponding to a heating container, the first sub-temperature controller can obtain the actual temperature value PV from the front temperature sensor of the heating container and send the power indication signal u(t) to the first sub-heater of the heating container. Similarly, if the sub-temperature controller is a second sub-temperature controller corresponding to a heating container, the second sub-temperature controller can obtain the actual temperature value PV from the rear temperature sensor of the heating container and send the power indication signal u(t) to the second sub-heater of the heating container.

[0066] The embodiments provided in this application can use a sub-temperature controller to perform PID adjustment on the temperature difference, generate a precise power indication signal, realize closed-loop dynamic control of the heating power of the sub-heater, improve the response speed of the heater, achieve high-precision temperature control, effectively suppress temperature fluctuations and overshoot, ensure that the temperature in the heating chamber stably approaches the set value, significantly improve the stability and uniformity of temperature control, and meet the requirements of rare earth sintering experiments for precise temperature control.

[0067] In an optional embodiment, such as Figure 6 As shown, each of the sub-heaters H includes a voltage regulator H01 and a heating unit H02. Specifically, the voltage regulator H01 is connected to the sub-temperature controller C, the external power supply E, and the heating unit H02, respectively, and is used to receive a preset voltage value from the external power supply E and supply power to the heating unit H02. The voltage value of the power supply can be 380V.

[0068] Among them, the voltage regulator H01 can be a power controller, and the heating unit H02 can include a transformer (not shown in the figure) connected in series and a heating device. The power controller is a device used to regulate and control the output power of electrical equipment. It precisely controls the power input of loads such as heaters, motors, and lights by adjusting voltage, current, or energizing time, thereby achieving stable control of physical quantities such as temperature, speed, and brightness. Furthermore, the heating device can be an induction heater or an arc heater. Furthermore, the voltage ratio of the transformer is a fixed value, which can be less than 1, to step down the supply voltage. This is used to convert the supply voltage in the range of 0 to 380V to the supply voltage in the range applicable to the heating device. For example, it can convert the supply voltage in the range of 0 to 380V to a voltage in the range of 0 to 38V to power the heating device.

[0069] Furthermore, the control terminal of the voltage regulator H01 is connected to the control terminal of the sub-temperature controller C, the power input terminal of the voltage regulator H01 is connected to the power output terminal of the external power supply E, the power output terminal of the voltage regulator H01 is connected to the primary winding of the transformer, and the secondary winding of the transformer is connected to the power supply terminal of the heating device.

[0070] Furthermore, the voltage regulator H01 is also used to receive the power indication signal, and to perform voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage, and to supply power to the heating unit H02 through the supply voltage.

[0071] Here, when the power indication signal is a current signal, the voltage regulator H01 performs voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage in the following ways:

[0072] First, the voltage regulator H01 determines the current value of the current signal and the current ratio between the current value and the preset current value; here, the preset current value is the benchmark for determining the magnitude of the current signal, and its value can be determined according to the actual situation.

[0073] As an example, if the current signal has a current value of 1A and the preset current value is 2A, then the current ratio is the current value divided by the preset current value, which equals 0.5.

[0074] Then, based on the current ratio value, the power supply voltage is stepped down proportionally to obtain the supply voltage, so that the voltage ratio value obtained by dividing the supply voltage value by the power supply voltage value is equal to the current ratio value.

[0075] As an example, if the current ratio is 0.5 and the power supply voltage is 380V, then by proportionally reducing the power supply voltage, the resulting supply voltage will be 190V.

[0076] Finally, the heating unit is powered by the supply voltage. Here, the voltage regulator H01 delivers the supply voltage to the transformer, which steps down the supply voltage according to a fixed voltage ratio to obtain the voltage value applicable to the heating device and then supplies power to the heating device.

[0077] As an example, the voltage regulator H01 delivers a 190V supply voltage to the transformer, which then steps down the supply voltage by a fixed voltage ratio to obtain a 19V supply voltage, which then powers the heating device.

[0078] Furthermore, when the power indication signal is a pulse width modulation signal, the voltage regulator H01 performs voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage in the following ways:

[0079] First, the voltage regulator H01 determines the duty cycle value of the pulse width modulation signal.

[0080] Then, based on the duty cycle value, the power supply voltage is stepped down proportionally to obtain the supply voltage, so that the voltage ratio obtained by dividing the supply voltage value by the power supply voltage value is equal to the current ratio value.

[0081] As an example, if the duty cycle of the pulse width modulation signal is 0.5 and the power supply voltage is 380V, then by proportionally reducing the power supply voltage, the resulting supply voltage is 190V.

[0082] Finally, the heating unit is powered by the supply voltage. As an example, the voltage regulator H01 delivers a 190V supply voltage to the transformer, which then steps down the supply voltage by a fixed ratio to obtain a 19V supply voltage, which is then used to power the heating device. The embodiments provided in this application achieve precise adjustment of the supply voltage to the heating unit by incorporating a voltage regulator in the sub-heater. The regulator dynamically adjusts the amplitude of the supply voltage based on the power indication signal output by the sub-temperature controller, thereby continuously and smoothly controlling the heating power and improving the accuracy and response speed of temperature regulation.

[0083] In an optional embodiment, such as Figure 7 As shown, the front temperature acquisition unit includes a front temperature sensor Tf, a first local temperature sensor T1, and multiple second local temperature sensors T2; wherein, the front temperature sensor Tf can be located at the center inside the front heating cavity 440. Figure 7 The position of the front temperature sensor Tf is only illustrative; it can be set in other locations to collect the central temperature value at the center of the front heating chamber 440.

[0084] Furthermore, the front temperature sensor Tf is used to collect the central temperature value of the front heating cavity 440. The first local temperature sensor T1 is disposed at the junction of the front heating cavity 440 and the rear heating cavity 450, and is used to collect the first local temperature value at its location. Each second local temperature sensor T2 is disposed at a different position at the end of the front heating cavity 440 away from the rear heating cavity 450, and is used to collect the second local temperature value at its location. Here, if the cross-section of the front heating cavity 440 at the through hole 460 is rectangular, then multiple second local temperature sensors T2 can be disposed at the four corners of this cross-section.

[0085] Furthermore, the first sub-temperature controller (not shown in the figure) is connected to the front temperature sensor Tf, the first local temperature sensor T1, and each of the second local temperature sensors T2 to obtain the central temperature value, the first local temperature value, and the second local temperature value.

[0086] Furthermore, after the heating phase of the heating container 400 ends and the heating container 400 is in a heat preservation state, the first sub-temperature controller acquires the actual temperature value collected by the front temperature acquisition device in real time in the following ways:

[0087] First, the first sub-temperature controller determines whether the first local temperature value is equal to the temperature setpoint.

[0088] Then, if the first local temperature value is equal to the temperature setpoint, the second local temperature average of all the second local temperature values ​​is calculated, and the temperature difference between the second local temperature average and the temperature setpoint is calculated.

[0089] Specifically, if the first local temperature value equals the set temperature value, then the second local temperature value is obtained from each second local temperature sensor T2, and the average second local temperature value of all second local temperature values ​​is calculated. The temperature difference between the average second local temperature value and the set temperature value is also calculated. Here, if the first local temperature value equals the set temperature value, it indicates that the center temperature of the heating cavity meets the requirements, and temperature correction only needs to consider the temperatures on both sides of the heating cavity.

[0090] For example, if the temperature setting is 1000 degrees Celsius and the calculated average second local temperature is 997 degrees Celsius, then the temperature difference is the second local temperature value minus the temperature setting, which is -3 degrees Celsius. If the temperature setting is 1000 degrees Celsius and the average second local temperature is 1003 degrees Celsius, then the temperature difference is 3 degrees Celsius.

[0091] Furthermore, the central temperature value is compensated based on the temperature difference value to obtain the actual temperature value. Specifically, the central temperature value can be obtained from the front thermometer Tf, and the actual temperature value is obtained by adding the temperature difference value to the central temperature value. As an example, if the central temperature value is 1000 degrees Celsius and the temperature difference value is -3 degrees Celsius, then the actual temperature value is 1000 + (-3) = 997 degrees Celsius. Similarly, if the central temperature value is 1000 degrees Celsius and the temperature difference value is 3 degrees Celsius, then the actual temperature value is 1000 + 3 = 1003 degrees Celsius.

[0092] Furthermore, if the first local temperature value is not equal to the set temperature value, the second local temperature value is obtained from each second local temperature sensor T2, and the average result of the sum of all second local temperature values ​​and the first local temperature values ​​is calculated to obtain the first global temperature average value. The temperature difference between the first global temperature average value and the set temperature value is then calculated. Here, if the first local temperature value is not equal to the set temperature value, it indicates that the center temperature value of the heating cavity does not meet the requirements, and temperature correction needs to comprehensively consider the temperatures on both sides and the center of the heating cavity.

[0093] As an example, if the temperature setpoint is 1000 degrees Celsius, and there are 4 second local temperature sensors T2, the second local temperature values ​​they collect are 997 degrees Celsius, 997 degrees Celsius, 996 degrees Celsius, and 998 degrees Celsius respectively. If the first local temperature is 996 degrees Celsius, then the first global average temperature is 996.8 degrees Celsius. The temperature difference is the first global average temperature minus the temperature setpoint, which is -3.2 degrees Celsius.

[0094] Furthermore, the central temperature value is compensated based on the temperature difference value to obtain the actual temperature value. As an example, if the central temperature value is 999 degrees Celsius and the temperature difference value is -3.2 degrees Celsius, then the actual temperature value is 999 + (-3.2) = 995.8 degrees Celsius.

[0095] Furthermore, such as Figure 7 As shown, the rear temperature acquisition unit includes a rear temperature sensor Tb, a third local temperature sensor T3, and multiple fourth local temperature sensors T4; wherein, the rear temperature sensor Tb can be located at the center inside the rear heating cavity 450. Figure 7 The position of the rear temperature sensor Tb is only illustrative; it can be set in other locations to collect the central temperature value at the center of the rear heating chamber 450.

[0096] The rear temperature sensor Tb is used to collect the central temperature value of the rear heating cavity 450. The third local temperature sensor T3 is located at the junction of the front heating cavity 440 and the rear heating cavity 450 and is used to collect the third local temperature value. Each fourth local temperature sensor T4 is located at a different position in the rear heating cavity 450 away from the front heating cavity 440 and is used to collect the fourth local temperature value at different positions. Here, if the cross-section of the bottom of the rear heating cavity 450 away from the front heating cavity 440 is rectangular, then multiple fourth local temperature sensors T4 can be set at the four corners of this cross-section.

[0097] Furthermore, the second sub-temperature controller is connected to the rear temperature sensor Tb, the third local temperature sensor T3, and each of the fourth local temperature sensors T4 to obtain the central temperature value, the third local temperature value, and the fourth local temperature value.

[0098] Furthermore, after the heating phase of the heating container 400 ends and the heating container 400 is in a heat preservation state, the second sub-temperature controller acquires the actual temperature value collected by the rear temperature acquisition device in real time in the following ways:

[0099] First, the second sub-temperature controller determines whether the third local temperature value is equal to the temperature setpoint;

[0100] Then, if the third local temperature value is equal to the temperature set value, the fourth local temperature average of all the fourth local temperature values ​​is calculated, and the temperature difference between the fourth local temperature average and the temperature set value is calculated.

[0101] Specifically, if the third local temperature value equals the set temperature value, then the fourth local temperature value is obtained from each fourth local temperature sensor T4, and the average fourth local temperature value of all fourth local temperature values ​​is calculated. The temperature difference between the average fourth local temperature value and the set temperature value is also calculated. Here, if the third local temperature value equals the set temperature value, it indicates that the center temperature of the heating cavity meets the requirements, and temperature correction only needs to consider the temperatures on both sides of the heating cavity.

[0102] For example, if the temperature setting is 1000 degrees Celsius and the calculated average fourth local temperature is 997 degrees Celsius, then the temperature difference is the fourth local temperature value minus the temperature setting value, which is -3 degrees Celsius. If the temperature setting is 1000 degrees Celsius and the fourth local temperature is 1003 degrees Celsius, then the temperature difference is 3 degrees Celsius.

[0103] Furthermore, the central temperature value is corrected based on the temperature difference value to obtain the actual temperature value. Specifically, the central temperature value can be obtained from the rear thermometer Tb, and the actual temperature value is obtained by adding the temperature difference value to the central temperature value. As an example, if the central temperature value is 1000 degrees Celsius and the temperature difference value is -3 degrees Celsius, then the actual temperature value is 1000 + (-3) = 997 degrees Celsius. Similarly, if the central temperature value is 1000 degrees Celsius and the temperature difference value is 3 degrees Celsius, then the actual temperature value is 1000 + 3 = 1003 degrees Celsius.

[0104] Furthermore, if the third local temperature value is not equal to the set temperature value, the fourth local temperature value is obtained from each fourth local temperature sensor T4, and the average result of the sum of all fourth local temperature values ​​and the third local temperature values ​​is calculated to obtain the second global temperature average value. The temperature difference between the second global temperature average value and the set temperature value is then calculated. Here, if the third local temperature value is not equal to the set temperature value, it indicates that the center temperature value of the heating cavity does not meet the requirements, and temperature correction needs to comprehensively consider the temperatures on both sides and the center of the heating cavity.

[0105] As an example, if the temperature setpoint is 1000 degrees Celsius, and there are four fourth local temperature sensors T4, the fourth local temperature values ​​they collect are 997 degrees Celsius, 997 degrees Celsius, 996 degrees Celsius, and 998 degrees Celsius, respectively. The third local temperature value is 996 degrees Celsius. Then the average second global temperature is 996.8 degrees Celsius, and the temperature difference is the average second global temperature minus the temperature setpoint, which is -3.2 degrees Celsius.

[0106] Furthermore, the central temperature value is compensated based on the temperature difference value to obtain the actual temperature value. As an example, if the central temperature value is 999 degrees Celsius and the temperature difference value is -3.2 degrees Celsius, then the actual temperature value is 999 + (-3.2) = 995.8 degrees Celsius.

[0107] Here, the front temperature sensor Tf and the rear temperature sensor Tb can be thermocouples, and the first local temperature sensor T1, the second local temperature sensor T2, the third local temperature sensor T3 and the fourth local temperature sensor T4 can be type K thermocouples.

[0108] Furthermore, such as Figure 8 As shown, the first local temperature sensor T1 and the third local temperature sensor T3 can be replaced by a central temperature sensor T0, which is located between the front heating cavity 440 and the rear heating cavity 450. It is connected to both the first and second sub-temperature controllers, collects the temperature value at its location, and sends this temperature value as the first local temperature value to the first sub-temperature controller, and as the third local temperature value to the second sub-temperature controller. The embodiments provided in this application improve the accuracy and representativeness of temperature acquisition through multi-point distributed temperature measurement and intelligent compensation mechanisms. Based on the matching judgment between local temperatures and set values, the central temperature sensor value is dynamically corrected, effectively reflecting the true heating state of the heating cavity, enhancing temperature control accuracy, ensuring a uniform and stable temperature field during sintering, and thus improving the sintering quality of the material.

[0109] The parallel vacuum sintering control system provided in this application enables simultaneous experiments at multiple sintering temperatures under the same vacuum or pressure environment. This solves the problem of traditional equipment being unable to compare multiple process parameters within the same environment, significantly improving the efficiency and data comparability of rare earth sintering experiments. Specifically, multiple independent heating containers are arranged in parallel within a common cavity, sharing a vacuum system to ensure a high degree of environmental consistency across temperature zones, while simultaneously increasing equipment utilization and reducing energy consumption and costs. Furthermore, each heating container is isolated from the others and employs a segmented heating chamber design, coupled with a multi-point distributed temperature measurement structure and PID-based power closed-loop control, achieving precise compensation and dynamic regulation of the temperature in each region. Moreover, the overall system possesses advantages such as uniform temperature field, low energy consumption, low material consumption, and flexible control, making it suitable for research on multi-condition sintering processes for high-performance materials such as rare earth magnetic materials.

[0110] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing this application. Those skilled in the art will understand that the modules in the apparatus of the embodiment can be distributed within the apparatus of the embodiment as described, or can be modified to be located in one or more apparatuses different from this embodiment. The modules of the above-described embodiment can be combined into one module, or further divided into multiple sub-modules.

[0111] The serial numbers in this application are for descriptive purposes only and do not represent the superiority or inferiority of any particular implementation scenario. The above disclosures are merely a few specific implementation scenarios of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A parallel vacuum sintering control system, characterized in that, The parallel vacuum sintering control system includes a furnace body, a vacuum pump, a furnace temperature controller, and multiple heating containers. The furnace temperature controller includes a central controller and multiple temperature controllers, and each temperature controller corresponds to one of the heating containers. Each of the heating containers is disposed in a hollow common cavity inside the furnace body. Each heating container has a heating cavity surrounded by heat-insulating material for holding the material to be heated. A through hole is provided on one side of the heating container so that the heating cavity of the heating container communicates with the common cavity. The air inlet of the vacuum pump is connected to the common cavity and is used to extract gas from the common cavity to create a vacuum environment in the common cavity. Each of the heating containers is equipped with a heater and a temperature acquisition device in its heating chamber. The heater and temperature acquisition device of each heating container are connected to the temperature controller corresponding to the heating container. The central controller is used to acquire the temperature setpoint corresponding to each of the heating containers and send the temperature setpoint to the temperature controller corresponding to the heating container; The temperature controller is connected to a heater inside the heating container and a temperature acquisition device to obtain the temperature setpoint, and to obtain the actual temperature value collected by the temperature acquisition device in real time. Based on the temperature difference between the actual temperature value and the temperature setpoint, the controller controls the heating power of the heater so that the actual temperature value inside the heating chamber of the heating container approaches the temperature setpoint. The heating chamber of the heating container includes a front heating chamber and a rear heating chamber that are connected to each other; The heater inside the heating container includes two sub-heaters, which are a first sub-heater and a second sub-heater. The first sub-heater is disposed in the front heating chamber, and the second sub-heater is disposed in the rear heating chamber. The temperature acquisition device inside the heating container includes a front temperature acquisition device and a rear temperature acquisition device. The front temperature acquisition device is used to acquire the actual temperature value of the front heating cavity, and the rear temperature acquisition device is used to acquire the actual temperature value of the rear heating cavity. The temperature controller includes two sub-temperature controllers, which include a first sub-temperature controller and a second sub-temperature controller. The first sub-temperature controller is used to acquire the temperature setpoint and acquire the actual temperature value collected by the front temperature collector in real time. Based on the temperature difference between the actual temperature value and the temperature setpoint, the controller controls the heating power of the first sub-heater so that the actual temperature value of the front heating chamber of the heating container approaches the temperature setpoint. The second sub-temperature controller is used to acquire the temperature setpoint and the actual temperature value collected by the rear temperature collector in real time. Based on the temperature difference between the actual temperature value and the temperature setpoint, the controller controls the heating power of the second sub-heater so that the actual temperature value of the rear heating chamber of the heating container approaches the temperature setpoint.

2. The parallel vacuum sintering control system according to claim 1, characterized in that, The temperature controller obtains the temperature setpoint in the following ways: Obtain a temperature value curve, wherein the horizontal axis of the temperature value curve is time, and the vertical axis of the temperature value curve is temperature value; Determine the current time point, and based on the time point, determine the temperature value corresponding to the time point in the temperature value curve, and set the temperature value as the temperature setpoint.

3. The parallel vacuum sintering control system according to claim 2, characterized in that, The sub-temperature controller is configured to perform the following processes: The sub-temperature controller acquires the temperature setpoint and the actual temperature value; Calculate the temperature difference between the set temperature value and the actual temperature value, and perform PID adjustment on the temperature difference to obtain a power indication signal; The power indication signal is sent to the sub-heater to control the heating power of the sub-heater.

4. The parallel vacuum sintering control system according to claim 3, characterized in that, Each of the sub-heaters includes a voltage regulator and a heating unit; The voltage regulator is connected to the sub-temperature controller, the external power supply and the heating unit respectively, and is used to receive a preset voltage value from the external power supply and supply power to the heating unit. The voltage regulator is also used to receive the power indication signal, and to perform voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage, and to supply power to the heating unit through the supply voltage.

5. The parallel vacuum sintering control system according to claim 4, characterized in that, The power indication signal is a current signal; the voltage regulator performs voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage in the following ways: Determine the current value of the current signal, and determine the current ratio between the current value and a preset current value; Based on the current ratio value, the voltage value of the power supply voltage is proportionally reduced to obtain the supply voltage, so that the voltage ratio between the supply voltage value and the power supply voltage value is equal to the current ratio value. The heating unit is powered by the aforementioned supply voltage.

6. The parallel vacuum sintering control system according to claim 4, characterized in that, The power indication signal is a pulse width modulation signal; the method by which the voltage regulator performs voltage conversion on the power supply voltage based on the power indication signal to obtain the supply voltage further includes: Determine the duty cycle value of the pulse width modulation signal; Based on the duty cycle value, the voltage value of the power supply voltage is proportionally reduced to obtain the supply voltage, so that the voltage ratio between the supply voltage value and the power supply voltage value is equal to the duty cycle value. The heating unit is powered by the aforementioned supply voltage.

7. The parallel vacuum sintering control system according to claim 3, characterized in that, The front temperature acquisition unit includes a front temperature sensor, a first local temperature sensor, and multiple second local temperature sensors. The front temperature sensor is used to collect the central temperature value of the front heating cavity. The first local temperature sensor is set at the junction of the front heating cavity and the rear heating cavity to collect the first local temperature value. Each second local temperature sensor is set at a different position in the front heating cavity away from the rear heating cavity to collect the second local temperature value at different positions. The first sub-temperature controller is connected to the front temperature sensor, the first local temperature sensor, and each of the second local temperature sensors to obtain the central temperature value, the first local temperature value, and the second local temperature value. The first sub-temperature controller acquires the actual temperature value collected by the front temperature acquisition unit in real time in the following ways: Determine whether the first local temperature value is equal to the temperature set value; If the first local temperature value is equal to the temperature set value, then calculate the second local temperature average of all the second local temperature values, and calculate the temperature difference between the second local temperature average and the temperature set value. The actual temperature value is obtained by compensating the central temperature value based on the temperature difference value.

8. The parallel vacuum sintering control system according to claim 3, characterized in that, The rear temperature acquisition unit includes a rear temperature sensor, a third local temperature sensor, and multiple fourth local temperature sensors. The rear temperature sensor is used to collect the central temperature value of the rear heating cavity. The third local temperature sensor is set at the junction of the front heating cavity and the rear heating cavity to collect the third local temperature value. Each of the fourth local temperature sensors is set at a different position in the rear heating cavity away from the front heating cavity to collect the fourth local temperature value at different positions. The second sub-temperature controller is connected to the rear temperature sensor, the third local temperature sensor, and each of the fourth local temperature sensors to obtain the central temperature value, the third local temperature value, and the fourth local temperature value. The second sub-temperature controller acquires the actual temperature value collected by the rear temperature acquisition unit in real time in the following ways: Determine whether the third local temperature value is equal to the temperature set value; If the third local temperature value is equal to the temperature set value, then calculate the fourth local temperature average of all the fourth local temperature values, and calculate the temperature difference between the fourth local temperature average and the temperature set value. The central temperature value is corrected based on the temperature difference value to obtain the actual temperature value.

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