Magnetic levitation temperature-controlled weighing stirrer and control method

Abstract

The application discloses a magnetic suspension temperature control weighing stirrer and a control method. The magnetic suspension temperature control weighing stirrer comprises a stirring barrel assembly, a magnetic suspension motor temperature control assembly, a base, a weighing sensor and a control system. The stirring barrel assembly comprises a stirring barrel and a stirring paddle. The bottom center of the stirring barrel is inwardly recessed to form a positioning portion with an internal cavity. The stirring paddle is sleeved on the positioning portion. The magnetic suspension motor temperature control assembly comprises a heat exchange plate abutting against the bottom of the stirring barrel, a magnetic suspension motor arranged at the center of the heat exchange plate and extending into the cavity at one end, and a ceramic refrigerating fin array arranged on the lower surface of the heat exchange plate. The weighing sensor is installed between the magnetic suspension motor and the base. The control system is electrically connected with the magnetic suspension motor, the ceramic refrigerating fin array and the weighing sensor. The application has the advantages of simultaneously realizing magnetic suspension pollution-free stirring, small-sized heating and cooling bidirectional precise temperature control based on the ceramic refrigerating fin array and real-time weighing.

Description

Technical Field

[0001] This invention relates to the field of mixing and stirring technology, specifically to a magnetically levitated temperature-controlled weighing stirrer and its control method. Background Technology

[0002] In experimental and industrial applications such as biomedicine, chemical synthesis, and precision materials preparation, stirring, temperature control, and weighing are three core and often coordinated basic operations. To achieve these functions, various types of equipment have been developed, but none have achieved efficient integration of these three elements.

[0003] 1. In terms of mixing technology

[0004] Existing stirring technologies are mainly divided into three categories: traditional magnetic stirring, insertion mechanical stirring, and magnetic levitation stirring. Chinese patent CN208742450U discloses a traditional magnetic stirrer, which drives a stirring paddle at the bottom of the container to rotate via a rotating magnetic field within the base. This design is simple in structure, but friction between the stirring paddle and the bottom of the container can easily generate particulate contamination. Chinese patent CN205659629U discloses an insertion stirrer, which uses a stirring paddle inserted from above the container for stirring. Although the stirring force is strong, the introduction of the stirring paddle also poses a risk of external contamination. Chinese patents CN204619879U and CN208130898U disclose stirrers based on the principle of magnetic levitation, where the stirring paddle is suspended in the liquid to achieve contactless rotation, effectively avoiding contamination problems. However, these devices are functionally limited, only providing stirring and failing to meet the comprehensive needs of complex processes for temperature control and quality monitoring.

[0005] 2. Temperature control technology

[0006] Existing temperature control solutions mainly include heating type, compressor refrigeration type, and circulating liquid temperature control type. Chinese patent CN208742450U discloses a solution integrating a heating plate within the base, but this solution only provides heating functionality. Chinese patent CN107469724A discloses a solution using a compressor refrigeration system, but its structure is complex, bulky, and noisy, making it unsuitable for miniaturized tabletop equipment. Chinese patent CN119727182A discloses a solution using an external circulating liquid bath for temperature control, but this solution also suffers from system complexity and the need for additional auxiliary equipment.

[0007] In recent years, thermoelectric coolers (TECs) based on the Peltier effect have been increasingly used in small temperature control devices due to their compact structure and ability to achieve bidirectional temperature control. However, existing TEC temperature control technologies have significant shortcomings: on the one hand, they mostly use simple ON / OFF switch control, which frequently starts and stops when approaching the target temperature. Furthermore, when shutting down, heat from the hot end is transferred back to the cold end, resulting in a "heating instead of cooling" phenomenon, causing significant temperature fluctuations and poor temperature control accuracy. On the other hand, existing TEC devices generally use a single temperature feedback loop and fixed PID parameters, which cannot effectively cope with the nonlinear characteristics of the TEC itself, changes in material load (such as different volumes and specific heat capacities), and environmental disturbances (such as power grid voltage fluctuations and stirring vibrations). This single control architecture not only makes it difficult to achieve high-precision (e.g., ±0.5℃) constant temperature control, but also fails to solve the temperature oscillation problem caused by frequent TEC starts and stops and heat transfer, making it difficult to meet the needs of high-end applications that are extremely sensitive to temperature, such as enzyme reactions, cell culture, and nanomaterial synthesis.

[0008] 3. Weighing function

[0009] Regarding weighing functionality, existing mixing equipment rarely integrates a weighing module. Researchers typically need to use separate balances to weigh items before and after mixing, which is cumbersome, inefficient, and prevents real-time quality monitoring during the reaction process, hindering precise control and optimization of the process. Summary of the Invention

[0010] The technical problem to be solved by this invention is to provide a magnetic levitation temperature-controlled weighing stirrer that can simultaneously achieve magnetic levitation pollution-free stirring, miniaturized bidirectional precise temperature control for heating and cooling based on a ceramic cooling plate array, and real-time weighing. The stirrer employs a dual closed-loop control algorithm with temperature and current loops. The current loop has a fast response speed, which can quickly suppress current interference caused by grid voltage fluctuations and ceramic cooling plate characteristic drift, stabilizing the power of the ceramic cooling plate. The temperature loop uses dynamic PID regulation, adjusting parameters in real time according to temperature deviation and rate of change, balancing response speed and stability, and avoiding overshoot and oscillation.

[0011] To solve the above-mentioned technical problems, the present invention provides a magnetic levitation temperature-controlled weighing stirrer, comprising:

[0012] A mixing tank assembly includes a mixing tank and a mixing paddle. The bottom center of the mixing tank is recessed inward to form a positioning part with an internal cavity, and the mixing paddle is sleeved on the positioning part.

[0013] The magnetic levitation motor temperature control assembly includes a heat exchange plate whose upper surface abuts against the bottom of the mixing tank, a magnetic levitation motor disposed at the center of the heat exchange plate and with one end extending into the cavity for suspending the stirring paddle by electromagnetic force and for driving the stirring paddle to rotate, and a ceramic cooling plate array disposed on the lower surface of the heat exchange plate for heating or cooling the mixing tank.

[0014] The base and a weighing sensor installed between the magnetic levitation motor and the base for real-time measurement of the total mass of the mixing tank assembly and the magnetic levitation motor temperature control assembly;

[0015] The control system is electrically connected to the magnetic levitation motor, the ceramic cooling array, and the weighing sensor.

[0016] In a preferred embodiment, a heat dissipation component is further included, which is disposed below the ceramic cooling chip array and is used to dissipate heat generated at the hot end of the ceramic cooling chip array.

[0017] In a preferred embodiment, the ceramic cooling chip array is arranged in a two-stage series structure, including a first ceramic cooling chip array, a heat-conducting plate, and a second ceramic cooling chip array;

[0018] The cold end of the first ceramic cooling chip array abuts against the lower surface of the heat exchange plate, and the hot end abuts against the upper surface of the heat-conducting plate;

[0019] The cold end of the second ceramic cooling chip array abuts against the lower surface of the heat-conducting plate, and the hot end abuts against the heat dissipation component.

[0020] In a preferred embodiment, the ceramic cooling chip array adopts a single-stage structure, with the cold end of the ceramic cooling chip array abutting against the lower surface of the heat exchange plate and the hot end abutting against the upper surface of the heat-conducting plate.

[0021] The lower surface of the heat-conducting plate abuts against the heat dissipation component.

[0022] In a preferred embodiment, the stirring impeller includes an annular magnet and a covered blade covering the outside of the annular magnet. The covered blade is provided with an annular inner surface adapted to the outer periphery of the positioning part, and a plurality of evenly distributed blades are provided on the outer periphery.

[0023] In a preferred embodiment, the control system includes:

[0024] A temperature detection module is used to obtain the temperature of the material inside the mixing tank;

[0025] A PWM voltage regulation module is electrically connected to the ceramic cooling array and is used to adjust the power supply voltage of the ceramic cooling array through pulse width modulation.

[0026] The PID control module is electrically connected to the temperature detection module and the PWM voltage regulation module. It is used to obtain the temperature deviation through the material temperature and the preset temperature, and based on the temperature deviation, drive the PWM voltage regulation module to adjust the cooling or heating power of the ceramic cooling array through the PID control algorithm.

[0027] In a preferred embodiment, the temperature detection module includes a temperature sensor, which is installed on the outside of the heat exchange plate and is used to collect the temperature of the outer wall of the mixing tank.

[0028] The control system is also used to obtain the temperature of the heat exchange plate based on the temperature of the outer wall of the mixing tank through a heat conduction model. If the temperature of the heat exchange plate is less than a preset threshold, the upper limit of the output duty cycle of the PWM voltage regulation module is limited.

[0029] The present invention also provides a control method for a magnetically levitated temperature-controlled weighing stirrer, applied to the magnetically levitated temperature-controlled weighing stirrer as described in any of the preceding claims, specifically including the following steps:

[0030] Real-time monitoring of material temperature inside the mixing tank;

[0031] The temperature deviation is obtained based on the material temperature and the preset temperature. The PID parameters are adjusted in real time based on the temperature deviation to obtain the current setpoint.

[0032] The actual operating current of the ceramic cooling array is obtained, and the current deviation is obtained based on the actual operating current and the current setting value.

[0033] Based on the current deviation, a PWM voltage regulation command is output through a PI control algorithm;

[0034] The power supply voltage of the ceramic cooling array is adjusted based on the PWM voltage regulation command to control its cooling or heating power.

[0035] In a preferred embodiment, the real-time acquisition of the material temperature inside the mixing tank specifically includes the following steps:

[0036] The temperature data set is formed by repeatedly collecting the temperature of the material inside the mixing tank.

[0037] Based on the temperature difference between any two adjacent materials in the temperature data set, if the difference is less than or equal to a preset difference threshold, the temperature data set is determined to be valid data. The temperature data set is then subjected to low-pass filtering to obtain the real-time material temperature.

[0038] If the difference is greater than a preset difference threshold, the temperature data set is determined to be invalid data, the temperature data set is deleted, and the above steps are repeated until the real-time material temperature is obtained.

[0039] A preferred embodiment further includes:

[0040] Obtain the stirring speed and / or material weight of the magnetic levitation temperature-controlled weighing stirrer;

[0041] Based on the stirring speed and / or the material weight, the PID parameters are optimized, and based on the optimized PID parameters, the current setpoint is corrected.

[0042] The magnetic levitation temperature-controlled weighing stirrer and control method disclosed in this invention have the following advantages compared with the prior art:

[0043] (1) A magnetic levitation temperature-controlled weighing stirrer of the present invention includes a stirring tank assembly, a magnetic levitation motor temperature control assembly, a base, a weighing sensor, and a control system. The stirring tank assembly includes a stirring tank and a stirring paddle. The stirring tank, as the core container, provides a physical carrier for the integration of the three functions of stirring, temperature control, and weighing, enabling the stirrer to have three core functions at the same time. This avoids the cumbersome operation of switching between multiple devices by the experimental personnel, effectively saves laboratory space, and improves work efficiency. The bottom center of the mixing tank is recessed inward to form a hollow positioning section. The stirring paddle is fitted onto this positioning section. This design achieves precise coaxial positioning of the stirring paddle, the central axis of the mixing tank, and the magnetic levitation motor, ensuring that the mixing tank and the magnetic levitation motor remain coaxial, maximizing magnetic coupling efficiency, and avoiding problems such as instability, energy loss, or stirring paddle jamming caused by eccentricity. Furthermore, the recessed design allows the magnetic levitation motor to be partially embedded in the bottom of the mixing tank, making full use of vertical space and effectively reducing the overall height of the equipment. This miniaturization allows the heat exchange plate to be tightly attached to the bottom of the mixing tank, forming a large thermal contact interface, shortening the heat conduction path, significantly improving heat exchange efficiency, and ensuring rapid temperature control response. This structural design simultaneously achieves positioning, drive coupling, and optimized heat conduction paths, demonstrating a high degree of structural integration.

[0044] The magnetic levitation motor temperature control assembly includes a heat exchange plate whose upper surface abuts against the bottom of the mixing tank; a magnetic levitation motor located at the center of the heat exchange plate with one end extending into a cavity, used to suspend the stirring paddle via electromagnetic force and drive the rotation of the stirring paddle; and an array of ceramic cooling plates located on the lower surface of the heat exchange plate for heating or cooling the mixing tank. The magnetic levitation motor simultaneously performs the dual functions of levitation and rotation of the stirring paddle. On one hand, the stirring paddle is suspended above the bottom of the mixing tank by the electromagnetic force generated by the magnetic levitation motor, with no direct mechanical contact with the container wall or bottom, completely eliminating particulate contamination caused by stirring paddle friction. This is particularly suitable for high-cleanliness experimental scenarios such as biopharmaceutical and cell culture. On the other hand, the magnetic levitation motor enables the stirring paddle to rotate smoothly in a suspended state, ensuring both the cleanliness of non-contact stirring and the uniformity and efficiency of the stirring. The structure of the ceramic cooling chip array has two advantages. First, it uses solid-state refrigeration technology, eliminating the need for large components such as compressors, condensers, and circulating fluids. The structure is compact, small in size, and noiseless, making it very suitable for use on laboratory benchtops and solving the problem of the large size of existing refrigeration solutions. Second, the array structure, compared with a single large-area cooling chip, can achieve a more uniform temperature distribution, avoid local overcooling or overheating, and improve temperature control uniformity.

[0045] The weighing sensor is installed between the magnetic levitation motor and the base to measure the total mass of the stirring tank assembly and the magnetic levitation motor temperature control assembly in real time. On the one hand, it eliminates the need for operators to use a separate balance to weigh the samples before and after stirring, improving work efficiency and avoiding the risk of sample loss or contamination during transfer. On the other hand, it enables continuous monitoring of material quality during the reaction process, providing real-time data support for process control.

[0046] (2) The magnetic levitation temperature-controlled weighing stirrer disclosed in this invention adopts a two-stage series structure for the ceramic cooling plate array, including a first ceramic cooling plate array, a heat-conducting plate, and a second ceramic cooling plate array. On the one hand, the two-stage series structure achieves a larger cooling temperature difference through the first-stage pre-cooling and the second-stage deep cooling. The two-stage array can be configured differently according to the cooling requirements (such as different power and different models) to achieve optimized matching of cooling capacity and improve energy utilization efficiency. On the other hand, heat is transferred from the heat exchange plate → cold end of the first ceramic cooling plate array → hot end of the first ceramic cooling plate array → heat-conducting plate → cold end of the second ceramic cooling plate array → hot end of the second ceramic cooling plate array → heat dissipation component, forming an orderly heat transfer path and avoiding the efficiency reduction caused by heat backflow. Ceramic thermoelectric cooler arrays can also be configured in a single-stage structure. The cold end of the array abuts against the lower surface of the heat exchange plate, the hot end against the upper surface of the heat-conducting plate, and the lower surface of the heat-conducting plate against the heat dissipation component. This single-stage structure features a short heat transfer path (heat exchange plate → ceramic thermoelectric cooler array → heat-conducting plate → heat dissipation component), low thermal inertia, and fast temperature response, allowing for rapid attainment of the set temperature. It also reduces the need for a second-stage ceramic thermoelectric cooler array, decreasing the number of components and assembly steps, thus lowering manufacturing costs. This design is suitable for general applications where high temperature difference requirements for cooling are not critical. Regardless of whether it's a two-stage or single-stage structure, it utilizes a PWM voltage regulation module and PID control algorithm to achieve continuous adjustment of the ceramic thermoelectric cooler's operating power, avoiding the frequent start-stop drawbacks of traditional ON / OFF control. In continuous adjustment mode, the ceramic thermoelectric cooler remains operational (only its power changes), eliminating the problem of heat flowing back from the hot end to the cold end when the array is turned off, thus resolving the "heat generation instead of cooling" phenomenon. The PID algorithm adjusts the PWM duty cycle in real time and continuously based on the temperature deviation, so that the output power of the ceramic cooling array is precisely matched with the heat load, achieving high-precision (±0.5℃) constant temperature control.

[0047] (3) The present invention discloses a control method for a magnetic levitation temperature-controlled weighing stirrer, comprising: real-time acquisition of the material temperature in the stirring tank; obtaining the temperature deviation based on the material temperature and the preset temperature; adjusting the PID parameters in real time based on the temperature deviation to obtain the current set value; acquiring the actual working current of the ceramic cooling array; obtaining the current deviation based on the actual working current and the current set value; outputting a PWM voltage regulation command through a PI control algorithm based on the current deviation; and adjusting the power supply voltage of the ceramic cooling array based on the PWM voltage regulation command to control its cooling or heating power. On the one hand, a dual closed-loop control architecture of "temperature loop (outer loop) + current loop (inner loop)" is introduced into the magnetic levitation temperature-controlled weighing stirrer. The temperature loop is responsible for dynamically adjusting the PID parameters and outputting the current setpoint according to the material temperature deviation, while the current loop is responsible for quickly adjusting the PWM output according to the current deviation. The inner and outer loops have clear division of labor and work together, which solves the problem that traditional single temperature loop control cannot take into account both temperature stability and response speed. On the other hand, current fluctuations are suppressed and the power of the ceramic cooling array is stabilized. By adding a current loop, the actual working current of the ceramic cooling array is monitored and adjusted in real time. This can quickly suppress current fluctuations caused by factors such as grid voltage fluctuations and the drift of the ceramic cooling characteristics, ensuring the stability of the output power of the ceramic cooling array and providing a stable execution basis for the temperature loop. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a magnetic levitation temperature-controlled weighing stirrer according to the present invention;

[0049] Figure 2 This is a schematic diagram of the stirring tank structure of an embodiment of the magnetic levitation temperature-controlled weighing stirrer of the present invention;

[0050] Figure 3 This is a cross-sectional view of the stirring paddle structure of an embodiment of a magnetic levitation temperature-controlled weighing stirrer according to the present invention;

[0051] Figure 4 This is a schematic diagram of a two-stage series structure of a ceramic cooling plate array according to an embodiment of a magnetic levitation temperature-controlled weighing stirrer of the present invention;

[0052] Figure 5 This is a schematic diagram of a single-stage structure of a ceramic cooling plate array according to an embodiment of a magnetic levitation temperature-controlled weighing stirrer of the present invention;

[0053] Figure 6 This is a flowchart illustrating the anti-icing protection technology of an embodiment of a magnetic levitation temperature-controlled weighing stirrer according to the present invention.

[0054] Figure 7 This is a flowchart illustrating the dual closed-loop control technology of an embodiment of a magnetic levitation temperature-controlled weighing stirrer according to the present invention.

[0055] Figure 8This is a flowchart illustrating the working condition adaptation and adjustment technology of an embodiment of the magnetic levitation temperature-controlled weighing stirrer of the present invention.

[0056] Figure 9 This is a technical flowchart illustrating the real-time acquisition of material temperature inside the mixing tank, according to an embodiment of a magnetic levitation temperature-controlled weighing stirrer of the present invention.

[0057] Explanation of reference numerals in the attached figures:

[0058] 1-Stirring tank; 11-Cavity; 12-Positioning part; 2-Stirring paddle; 21-Annular magnet; 22-Covered blade; 221-Annular inner surface; 222-Blade; 3-Heat exchange plate; 4-Magnetic levitation motor; 5-Ceramic cooling plate array; 51-First ceramic cooling plate array; 52-Heat-conducting plate; 53-Second ceramic cooling plate array; 6-Base; 7-Weighing sensor; 8-Heat dissipation component; 9-Temperature sensor. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0061] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0062] Example 1

[0063] This embodiment describes a magnetically levitated temperature-controlled weighing stirrer, such as... Figure 1As shown, the system includes a stirring tank assembly, a magnetic levitation motor temperature control assembly, a base 6, a weighing sensor 7, a heat dissipation assembly 8, and a control system. The stirring tank assembly includes a stirring tank 1 and a stirring paddle 2. The stirring tank, as the core container, provides the physical carrier for the integration of stirring, temperature control, and weighing functions, enabling the stirrer to simultaneously perform these three core functions. This avoids the cumbersome process of switching between multiple devices, effectively saves laboratory space, and improves work efficiency. Specifically, the stirring tank 1 is used to hold the materials to be stirred and reacted. Its material can be stainless steel or corrosion-resistant plastic, and its capacity can be set from 500mL to 5L according to experimental needs. Figure 2 As shown, a positioning part 12 with an internal cavity 11 is formed by an inward recess at the bottom center of the mixing tank, and the stirring paddle is fitted onto the positioning part. In this embodiment, the positioning part 12 adopts a cylindrical protrusion structure, which is recessed into the mixing tank 1, thereby forming a receiving space on the outer side of the bottom of the mixing tank 1. The stirring paddle 2 is disposed inside the mixing tank 1 and fitted onto the outer periphery of the positioning part 12. The structural design of the positioning unit 12 achieves "one form, three uses": First, its internal cavity 11 accommodates the stator of the magnetic levitation motor 4, achieving coaxial positioning of the mixing tank 1 and the drive motor, ensuring magnetic coupling efficiency, and avoiding problems such as unstable stirring, energy loss, or impeller jamming caused by eccentricity; second, it shortens the magnetic distance between the motor and the impeller 2, enhancing the drive coupling effect; finally, the flat area at the bottom of the mixing tank 1 can fit tightly with the heat exchange plate 3 below, making full use of vertical space, effectively reducing the overall height of the equipment, achieving miniaturization, and allowing the heat exchange plate to fit tightly against the bottom of the mixing tank, forming a large-area thermal contact interface, shortening the heat conduction path, significantly improving heat exchange efficiency, and ensuring rapid response of temperature control. This structural design simultaneously achieves positioning, drive coupling, and optimized heat conduction paths, demonstrating a high degree of structural integration.

[0064] Agitator 2, such as Figure 3 As shown, the impeller includes an annular magnet 21 and a covered impeller 22 covering the outer side of the annular magnet 21. The covered impeller has an annular inner surface 221 that matches the outer periphery of the positioning part, and multiple evenly distributed impeller blades 222 are arranged on the outer periphery. This structural design allows the impeller 2 to maintain a small and uniform gap between its annular inner surface 221 and the outer periphery of the positioning part 12 when suspended, avoiding wear and particulate contamination caused by mechanical contact and ensuring the high efficiency of magnetic coupling. The evenly distributed impeller blades 222 can generate good axial and radial flow when rotating, eliminating dead zones in the mixing and improving the uniformity of material mixing. In this embodiment, the covered impeller 22 is usually made of corrosion-resistant polymer material (such as PP) and is integrally injection molded to completely cover the annular magnet 21, which protects the magnet from material corrosion and ensures the overall chemical stability of the impeller.

[0065] The magnetic levitation motor temperature control assembly includes a heat exchange plate 3 whose upper surface abuts against the bottom of the mixing tank; a magnetic levitation motor 4 located at the center of the heat exchange plate and extending one end into the cavity, used to levitate the stirring paddle via electromagnetic force and drive the stirring paddle to rotate; and a ceramic cooling plate array 5 located on the lower surface of the heat exchange plate for heating or cooling the mixing tank. In this embodiment, the heat exchange plate 3, as the intermediate medium for heat transfer, is typically made of aluminum alloy or copper with high thermal conductivity. Its upper surface is designed as a flat plane, closely fitting the flat area at the bottom of the mixing tank 1 to ensure a smooth heat conduction path, enabling rapid transfer of the cold or heat generated by the ceramic cooling plate array 5 to the mixing tank 1. The magnetic levitation motor 4 is located at the center of the heat exchange plate 3, with its stator extending upward into the cavity 11 at the bottom of the mixing tank 1. The generated rotating magnetic field penetrates the cavity wall and couples with the magnets inside the stirring paddle 2, thereby achieving contactless levitation and rotational drive of the stirring paddle 2, avoiding the wear and material contamination problems associated with traditional mechanical stirring. The ceramic cooling plate array 5 is located on the lower surface of the heat exchange plate 3. Based on the Peltier effect, cooling or heating functions can be achieved by changing the direction of the current, thereby enabling precise temperature control of the materials in the mixing tank 1. The magnetic levitation motor serves a dual function of suspending and rotating the stirring paddle. On the one hand, the stirring paddle is suspended above the bottom of the mixing tank by the electromagnetic force generated by the magnetic levitation motor, without direct mechanical contact with the container wall and bottom, completely eliminating particulate matter contamination caused by stirring paddle friction. This is particularly suitable for experimental scenarios with high cleanliness requirements, such as biopharmaceuticals and cell culture. On the other hand, the magnetic levitation motor enables the stirring paddle to rotate smoothly in a suspended state, ensuring both the cleanliness of non-contact stirring and the uniformity and efficiency of stirring. The structure of the ceramic cooling plate array, through solid-state refrigeration technology, eliminates the need for large components such as compressors, condensers, and circulating fluids. The structure is compact, small in size, and noiseless, making it ideal for use on laboratory benchtops and solving the problem of the bulkiness of existing refrigeration solutions. Furthermore, the array structure, compared to a single large-area cooling plate, can achieve a more uniform temperature distribution, avoiding localized overcooling or overheating and improving temperature control uniformity.

[0066] A weighing sensor 7 is installed between the magnetic levitation motor and the base to measure the total mass of the stirring tank assembly and the magnetic levitation motor temperature control assembly in real time. Specifically, the base 6 serves as the supporting carrier for the entire device, bearing all the aforementioned components. The weighing sensor 7 is cleverly positioned directly below the magnetic levitation motor 4, with its upper end fixedly connected to the magnetic levitation motor temperature control assembly (including the heat dissipation assembly and other integrated modules), and its lower end fixedly connected to the base 6. This arrangement allows the weighing sensor 7 to sense and measure the total mass change of all components above it (including the stirring tank assembly and the magnetic levitation motor temperature control assembly) in real time. On the one hand, during the experiment, the operator does not need to use a separate balance for weighing before and after stirring, improving work efficiency and avoiding the risk of sample loss or contamination during transfer; on the other hand, it enables continuous monitoring of material quality during the reaction process, providing real-time data support for process control.

[0067] The control system is electrically connected to the magnetic levitation motor, the ceramic cooling array 5, and the weighing sensor 7. Specifically, the control system is typically integrated into the main control circuit board inside the base 6, and is electrically connected to the magnetic levitation motor 4, the ceramic cooling array 5, and the weighing sensor 7 via wires. The control system is responsible for coordinating the work of each component, such as adjusting the stirring speed based on feedback from the weighing sensor 7, or adjusting the power of the ceramic cooling array 5 based on temperature feedback, to achieve coordinated operation of stirring, temperature control, and weighing functions. Through the above structural layout, this embodiment achieves a high degree of integration of the three major functions of stirring, temperature control, and weighing. The positioning part 12 at the bottom of the stirring tank 1 not only simplifies the structure but also simultaneously meets the triple requirements of positioning, drive coupling, and heat conduction. The application of the magnetic levitation motor 4 enables contactless stirring, avoiding material contamination. The lower structural layout of the weighing sensor 7 ensures the accuracy of weighing. The overall structure is compact, occupies little space, and is very suitable for use on laboratory benchtops.

[0068] A heat dissipation component is positioned below the ceramic cooling chip array to dissipate heat generated at the hot end of the array. Preferably, the ceramic cooling chip array 5 employs a two-stage series structure, such as... Figure 4 As shown, it includes a first ceramic cooling chip array 51, a heat-conducting plate 52, and a second ceramic cooling chip array 53;

[0069] The cold end of the first ceramic cooling plate array abuts against the lower surface of the heat exchange plate, and the hot end abuts against the upper surface of the heat-conducting plate.

[0070] The cold end of the second ceramic thermoelectric array abuts against the lower surface of the heat-conducting plate, while the hot end abuts against the heat dissipation component. On one hand, the two-stage series structure, through first-stage pre-cooling and second-stage deep cooling, achieves a larger temperature difference for cooling. The two arrays can be configured differently according to cooling requirements (e.g., different power levels, different models) to optimize cooling capacity and improve energy efficiency. On the other hand, heat flows from the heat exchange plate → cold end of the first ceramic thermoelectric array → hot end of the first ceramic thermoelectric array → heat-conducting plate → cold end of the second ceramic thermoelectric array → hot end of the second ceramic thermoelectric array → heat dissipation component, forming an orderly heat transfer path and avoiding efficiency loss due to heat recirculation.

[0071] Preferably, the ceramic cooling array 5 adopts a single-stage structure. The cold end of the ceramic cooling array abuts against the lower surface of the heat exchange plate, the hot end abuts against the upper surface of the heat-conducting plate, and the lower surface of the heat-conducting plate abuts against the heat dissipation component. The single-stage structure has a short heat transfer path (heat exchange plate → ceramic cooling array → heat-conducting plate → heat dissipation component), low thermal inertia, and fast temperature response, enabling it to quickly reach the set temperature. This reduces the need for a second-stage ceramic cooling array, decreases the number of parts and assembly steps, and lowers the equipment manufacturing cost, making it suitable for conventional applications where the temperature difference requirement for cooling is not high. Regardless of whether it is a two-stage or single-stage structure, it is equipped with a PWM voltage regulation module and PID control algorithm to achieve continuous adjustment of the ceramic cooling power, avoiding the drawbacks of frequent start-stop in traditional ON / OFF control. In continuous adjustment mode, the ceramic cooling element always remains in working state (only the power changes), and there is no problem of heat being transferred from the hot end to the cold end when it is turned off, solving the phenomenon of "heat generation instead of cooling". The PID algorithm adjusts the PWM duty cycle in real time and continuously based on the temperature deviation, so that the output power of the ceramic cooling array is precisely matched with the heat load, achieving high-precision (±0.5℃) constant temperature control.

[0072] In this embodiment, the control system includes:

[0073] The temperature detection module is used to obtain the temperature of the material inside the mixing tank 1;

[0074] A PWM voltage regulation module is electrically connected to the ceramic cooling array and is used to adjust the power supply voltage of the ceramic cooling array through pulse width modulation.

[0075] The PID control module, electrically connected to the temperature detection module and the PWM voltage regulation module, is used to obtain the temperature deviation between the material temperature and the preset temperature. Based on the temperature deviation, it drives the PWM voltage regulation module to adjust the cooling or heating power of the ceramic cooling array using a PID control algorithm. Specifically, the temperature detection module is responsible for sensing the material temperature in the mixing tank 1 in real time, serving as the feedback input for the temperature control closed loop. The PWM voltage regulation module, electrically connected to the ceramic cooling array 5, converts the control signal into a power signal to drive the ceramic cooling array 5. It adjusts the supply voltage using pulse width modulation (PWM) technology, thereby achieving continuous and precise adjustment of the cooling or heating power, avoiding the temperature shocks and fluctuations caused by traditional relay ON / OFF control. The PID control module, acting as the "brain" of the entire control system, is electrically connected to both the temperature detection module and the PWM voltage regulation module. It receives the real-time material temperature uploaded by the temperature detection module, compares it with the user-preset target temperature to calculate the temperature deviation, and then, based on this temperature deviation, uses the built-in PID control algorithm to calculate the required adjustment amount, driving the PWM voltage regulation module to adjust the power output of the ceramic cooling array 5 accordingly. This PID-based closed-loop control architecture can effectively eliminate steady-state errors and improve the system's response speed and stability. In this embodiment, the PID control algorithm is implemented using the following calculation method:

[0076] ,

[0077] in, To control the PWM duty cycle of the adjustment quantity, For temperature deviation, This is the proportionality coefficient. The integral coefficient is... is the differential coefficient.

[0078] Regarding the specific configuration of the temperature detection module, in a preferred embodiment, the temperature detection module includes a temperature sensor 9. The temperature sensor 9 is installed on the outside of the heat exchange plate 3 and is used to collect the temperature of the outer wall of the mixing tank 1 through non-contact acquisition. Since the mixing tank 1 is typically made of stainless steel or other metal materials, which have good thermal conductivity, the outer wall temperature can indirectly reflect the temperature of the material inside the tank. This temperature measurement method avoids the sealing hazards and cleaning difficulties caused by opening holes in the mixing tank 1 to install the sensor, and is particularly suitable for experimental scenarios requiring sterility or high cleanliness. It should be understood that in other embodiments, for example, a thermocouple or thermistor can be inserted into the material from the top of the mixing tank 1 to obtain more accurate direct temperature data, or as a calibration supplement to external temperature measurement.

[0079] The control system also reuses temperature sensor 9 to implement anti-icing protection. Specifically, when the equipment is in cryogenic operating mode (e.g., the target temperature is set below 0℃), the surface temperature of heat exchange plate 3 is extremely low. If the ambient humidity is high at this time, condensation and icing are very likely to occur at the contact surface or edge between heat exchange plate 3 and stirring tank 1. The thermal conductivity of ice is much lower than that of metal. Once formed, it will severely hinder heat transfer, leading to temperature control failure and even damage to the equipment. To solve this problem, the control system obtains the temperature of heat exchange plate 3 based on the outer wall temperature of stirring tank 1 through a preset heat conduction model. In this embodiment, the heat conduction model is established based on Fourier's law of thermal conductivity and can inversely calculate the temperature distribution on the surface of heat exchange plate 3 based on the outer wall temperature measured by temperature sensor 9. The heat conduction model is specifically implemented using the following calculation method:

[0080] ,

[0081] in, The temperature of the surface of heat exchange plate 3. The temperature of the outer wall of mixing tank 1. The heat flux density at the current moment, For total thermal resistance, Thermal inertia coefficient This represents the rate of temperature change of the outer wall of the mixing tank.

[0082] like Figure 6 As shown, based on the outer wall temperature of the mixing tank 1, the temperature of the heat exchange plate 3 is obtained through a heat conduction model. If the temperature of the heat exchange plate is less than a preset threshold, the upper limit of the output duty cycle of the PWM voltage regulation module is limited. When the control system calculates through the above model that the temperature of the heat exchange plate 3 is less than the preset threshold (e.g., set to 2℃ or a safety margin value close to the freezing point), the system determines that there is a risk of icing and triggers the anti-icing protection logic, limiting the upper limit of the output duty cycle of the PWM voltage regulation module. Specifically, the system will forcibly reduce the maximum cooling power of the ceramic cooling array 5, so that the temperature of the heat exchange plate 3 no longer continues to drop or slowly rises, thereby preventing the surface temperature from falling below the freezing point. This control strategy is not a simple shutdown protection, but dynamically adjusts the power output boundary while ensuring the cooling effect, preventing the risk of icing and maintaining the continuous operation capability of the system. This function is achieved by reusing the temperature sensor 9, eliminating the need to add an additional temperature sensor to specifically monitor the temperature of the heat exchange plate 3, effectively reducing hardware costs, simplifying the equipment structure, and demonstrating the advantages of hardware and software co-design.

[0083] Example 2

[0084] This embodiment presents a control method for a magnetically levitated temperature-controlled weighing stirrer. This method is applied to the magnetically levitated temperature-controlled weighing stirrer described in Embodiment 1 above, aiming to solve the problems of delayed response and weak anti-interference capability of a single temperature loop control through a dual-closed-loop control architecture. For example... Figure 7 As shown, the specific steps include the following:

[0085] Step S1 involves real-time acquisition of the material temperature inside the mixing tank. Specifically, this step is performed by the temperature detection module described in Example 1 above. For example, the temperature can be obtained by acquiring the temperature of the outer wall of the mixing tank through a temperature sensor and then calculated, or it can be directly measured by a temperature sensor inserted into the material. The acquired temperature data serves as the feedback input signal for the entire control system.

[0086] Step S2 involves obtaining the temperature deviation based on the material temperature and the preset temperature, and adjusting the PID parameters in real time based on the temperature deviation to obtain the current setpoint. This step constitutes the "temperature loop," or outer loop, in the control circuit. Specifically, the control system compares the real-time collected material temperature with the user-set target temperature and calculates the difference between the two, which is the temperature deviation. Unlike traditional fixed-parameter PID controllers, this embodiment employs a dynamic PID adjustment strategy, adjusting the proportional, integral, and derivative coefficients in real time according to the magnitude of the temperature deviation and its rate of change (i.e., the change in temperature deviation per unit time). For example, when the temperature deviation is large, the proportional coefficient is appropriately increased to accelerate the response speed, while the integral coefficient is decreased to avoid overshoot caused by integral saturation; when the temperature deviation is small and changes gradually, the integral coefficient is increased to eliminate static error. After PID calculation, a target current value, or current setpoint, is output, which represents the target operating current required by the ceramic cooling array to eliminate the temperature deviation. It should be understood that the temperature loop operation frequency is usually low, for example, set to 10Hz, to match the gradual change characteristics of temperature.

[0087] Step S3: Obtain the actual operating current of the ceramic cooler array and calculate the current deviation based on the actual operating current and the current setpoint. This step is the "current loop," the preparation stage of the inner loop. Specifically, the actual current value flowing through the ceramic cooler array is acquired in real time through a current sampling circuit (such as a Hall sensor or sampling resistor) connected in series in the power supply circuit of the ceramic cooler array. The control system calculates the difference between this actual current value and the current setpoint output by the temperature loop to obtain the current deviation.

[0088] Step S4: Based on the current deviation, a PWM voltage regulation command is output through a PI control algorithm. This step constitutes the "current loop," or inner loop, in the control circuit. Specifically, the current loop uses a PI (Proportional-Integral) control algorithm to process the current deviation. Because the current signal changes much faster than the temperature signal, the operating frequency of the current loop is much higher than that of the temperature loop, for example, set to 1000Hz. This high-frequency regulation can quickly respond to current fluctuations caused by grid voltage fluctuations or load transients. When the actual current deviates from the set value, the PI algorithm quickly calculates and outputs a PWM voltage regulation command, which corresponds to a specific PWM duty cycle value.

[0089] Step S5 involves adjusting the supply voltage of the ceramic cooling array based on PWM voltage regulation commands to control its cooling or heating power. Specifically, the PWM voltage regulation module receives the aforementioned commands and changes the average voltage applied across the ceramic cooling array by adjusting the conduction time of the switching transistor, thereby precisely controlling its operating current and achieving precise adjustment of the cooling or heating power. Through the above dual closed-loop control method, this embodiment achieves fine-grained temperature control. Its core advantage lies in the introduction of a current loop as the inner loop: In traditional single temperature loop control, when the mains voltage fluctuates or the ceramic cooling element's own characteristics drift, causing changes in the operating current, the temperature loop must wait for this change to cause temperature fluctuations before reacting. This lag can easily lead to temperature oscillations. In this embodiment, the current loop can directly and quickly lock the operating current, suppressing current fluctuations before they cause significant temperature changes, thus eliminating internal disturbances. Simultaneously, the temperature loop is responsible for outputting the current target based on the macroscopic temperature deviation, ensuring that the final temperature stabilizes at the set value. This collaborative mechanism of "outer loop setting target and inner loop resisting interference" effectively solves the common problems of "not cooling but heating" and temperature overshoot in ceramic refrigeration temperature control, and achieves high-precision temperature control of ±0.5℃.

[0090] Example 3

[0091] This embodiment, based on Embodiment 2, provides a detailed explanation of the anti-interference processing logic during temperature acquisition and the PID parameter adaptation adjustment for different operating conditions. In actual fully suspended mixing processes, the high-speed rotation of the mixing paddle, the slight vibration of the magnetic levitation bearing, and signal fluctuations from the weighing sensor all generate high-frequency interference to temperature acquisition; simultaneously, different material weights and mixing speeds alter the system's thermodynamic characteristics. Without processing, this will lead to distorted temperature data or mismatched control parameters, affecting temperature control accuracy. Regarding anti-interference processing for temperature acquisition, such as… Figure 9 As shown, the real-time temperature of the material inside the mixing tank is collected, specifically including the following steps:

[0092] Step S101 involves continuously collecting the temperature of the material inside the mixing tank multiple times to form a temperature data set. Specifically, the control system continuously collects temperature data N times at a preset sampling frequency (e.g., 10Hz), where N is preferably 3 or 5 times, forming a temperature data set. This grouped acquisition method provides a data basis for subsequent outlier detection.

[0093] Step S102: Based on the temperature difference between any two adjacent material temperatures in the temperature data set, if the difference is less than or equal to a preset difference threshold, the temperature data set is determined to be valid. Specifically, considering that temperature is a thermodynamic quantity with large inertial characteristics, it is unlikely to undergo drastic changes in a very short time. The system calculates the absolute value of the difference between any two adjacent collected values ​​within the data set and compares it with a preset difference threshold (e.g., 0.5℃). If all adjacent differences are less than or equal to this threshold, it indicates that the acquisition process is stable and there is no sudden interference, and the data set is determined to be valid. Conversely, if the difference is greater than the preset difference threshold, the temperature data set is determined to be invalid, the temperature data set is deleted, and the above steps are repeated until the real-time material temperature is obtained. This logic can effectively eliminate abnormal values ​​caused by electromagnetic interference, poor contact, or instantaneous vibration, ensuring that the feedback signal entering the control loop is true and reliable.

[0094] Step S103: The temperature data set is low-pass filtered to obtain the real-time material temperature. Specifically, for data sets deemed valid, the system further employs a first-order low-pass filtering algorithm, implemented using the following calculation method:

[0095] ,

[0096] in, This is the real-time material temperature after filtering. This represents the average of the current valid data set. This is the temperature value after the previous filtering. The filter coefficient (preferably ranging from 0.2 to 0.3).

[0097] This step filters out high-frequency random noise superimposed on the temperature signal, making the temperature feedback curve smoother and avoiding frequent fluctuations in control output caused by signal jitter. Through the dual processing of "outlier removal + low-pass filtering" described above, the temperature acquisition error can be controlled within a very small range (e.g., ±0.03℃), laying the foundation for high-precision temperature control.

[0098] Preferably, adjustments are made to adapt to different operating conditions, such as... Figure 8 As shown, the method in this embodiment further includes the following steps:

[0099] Step S201: Obtain the stirring speed and / or material weight of the magnetic levitation temperature-controlled weighing agitator. Specifically, the stirring speed can be directly read from the driver of the magnetic levitation motor, and the material weight can be obtained in real time from the weighing sensor. These two parameters directly reflect the current thermal load and fluid dynamics state of the system.

[0100] Step S202: Optimize the PID parameters based on the stirring speed and / or the material weight. Specifically, the PID parameters ( proportionality coefficient Integral coefficient, The differential coefficients are not fixed values, but variables that are dynamically adjusted according to the operating conditions.

[0101] As a specific implementation method, when the stirring speed is high (e.g., greater than 200 r / min), the fluid turbulence intensifies, the convective heat transfer coefficient between the material and the tank wall and heat exchange plates increases, the heat dissipation rate accelerates, and the temperature change rate also accelerates. At this time, the control system automatically increases the proportional gain. (For example, increase by 10%-15%) to accelerate the system's response to temperature deviations; at the same time, appropriately reduce the integral coefficient. (For example, reduce it by 5%-10%) to avoid integral saturation or temperature overshoot caused by rapid heat dissipation. Conversely, when the stirring speed is low, the fluid mixing uniformity deteriorates, and temperature distribution is prone to stratification. In this case, appropriately reducing the stirring speed is advisable. and increase This is to eliminate static errors caused by local temperature differences.

[0102] As another specific implementation, when the material weight is large (e.g., greater than 500g), the system's heat capacity increases, and the temperature change caused by the same heating or cooling power becomes smaller, meaning the system's thermal inertia increases. In this case, the control system automatically increases the proportional gain. (e.g., increase by 15%-20%) and integral coefficient (For example, increasing it by 10%-15%) provides greater control and overcomes the hysteresis effect caused by high heat capacity. Conversely, when the material weight is small, the system heat capacity is small, and the temperature is easily affected by disturbances and fluctuations. In this case, appropriately reducing the heat capacity is appropriate. and This is to prevent excessive control actions from causing temperature fluctuations.

[0103] Step S203: Based on the optimized PID parameters, the current setpoint is corrected. Specifically, the PID parameters optimized for the above-mentioned operating conditions are substituted into the calculation formula of the temperature loop, making the output current setpoint more closely match the current actual operating conditions. This ensures that the system's temperature control accuracy can be stably maintained within ±0.5℃ across the entire speed range and scale range. This adaptive adjustment mechanism solves the problem of decreased temperature control performance of traditional fixed-parameter PID algorithms when operating conditions change, demonstrating a deep integration of the algorithm and the structural characteristics of the equipment.

[0104] Example 4

[0105] To more clearly illustrate the technical effects of the magnetic levitation temperature-controlled weighing stirrer and its control method provided by this invention, this embodiment uses a pharmaceutical intermediate synthesis reaction as an example for detailed explanation. This reaction is extremely sensitive to temperature, requiring the reaction temperature to be controlled at 4℃±0.5℃, and the reaction process is accompanied by exothermic phenomena, requiring the addition of solid raw materials in stages.

[0106] Before the reaction begins, the operator adds the reactants to the mixing tank 1 and sets the target temperature to 4°C via the control panel. After the control system starts, it first performs a temperature acquisition and anti-interference processing step. The temperature sensor 9 continuously acquires the temperature of the outer wall of the mixing tank 1 at a frequency of 10Hz, and the control system performs differential judgment on the continuously acquired temperature data sets. Since the material temperature is close to the ambient temperature at the beginning of the reaction, the acquired data is stable, the system determines the data to be valid, and performs low-pass filtering to obtain accurate initial temperature feedback.

[0107] Subsequently, the dual-loop control algorithm kicks in. The temperature loop calculates the required current setpoint based on the deviation between the real-time temperature and the target temperature. Due to the large initial temperature difference, the temperature loop's dynamic PID control module automatically increases the proportional gain. To accelerate the cooling rate while reducing the integral coefficient To avoid integral saturation, the current loop outputs a PWM voltage regulation command via a PI algorithm based on the current setpoint, driving the ceramic cooling array 5 to operate at rated power. Meanwhile, the magnetic levitation motor 4 drives the stirring paddle 2 to rotate at low speed, ensuring uniform mixing of materials. Thanks to the rapid response of the current loop, minor fluctuations in the grid voltage are promptly suppressed, and the operating current of the ceramic cooling array 5 remains stable near the setpoint, guaranteeing a constant output of cooling power.

[0108] After the reaction has proceeded for a certain period, the operator increases the stirring speed to enhance mixing, according to process requirements. This change in operating condition is immediately detected by the operating condition adaptation and adjustment module. Because the increased speed leads to a higher convective heat transfer coefficient between the material and the tank wall, and a faster heat dissipation rate, using the original PID parameters might result in temperature control lag. Based on the change in stirring speed, the control system automatically optimizes the PID parameters, appropriately increasing the proportional gain. (For example, increase by 12%) and decrease the integral coefficient. (For example, reducing it by 8%), thereby accelerating the response speed of the temperature loop and offsetting the effect of increased heat dissipation. Simultaneously, the operator slowly adds solid raw materials through the feed port, gradually increasing the weight of the material in mixing tank 1. Weighing sensor 7 monitors the weight change in real time and feeds the data back to the control system. Because the material's heat capacity increases with weight, the inertia of temperature changes increases. The control system then corrects the PID parameters again, increasing the proportional and integral coefficients to provide greater adjustment power and ensure that the temperature does not fluctuate significantly due to the increased heat capacity.

[0109] During the cryogenic reaction, the anti-icing protection function is constantly monitored. Temperature sensor 9 continuously collects the temperature of the outer wall of the mixing tank 1, and the system's built-in heat conduction model uses this temperature to calculate the surface temperature of the heat exchange plate 3. When the calculated temperature approaches the preset icing risk threshold (e.g., 2℃), although the material temperature is still above 4℃, the system anticipates a potential icing risk on the surface of the heat exchange plate 3 and triggers the anti-icing protection logic, limiting the upper limit of the PWM voltage regulation module's output duty cycle and appropriately reducing the cooling power. This intervention keeps the temperature of the heat exchange plate 3 above the freezing point, effectively preventing condensation and ensuring unobstructed heat conduction.

[0110] Throughout the reaction process, despite the increase in rotation speed and the addition of materials, the material temperature inside the mixing tank 1 remained stable within the range of 4℃±0.5℃, without any significant overshoot or oscillation. After the reaction, the purity of the product was tested and found to be as expected, proving that the present invention can still achieve high-precision and high-stability temperature control under complex working conditions.

[0111] In summary, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetically levitated temperature-controlled weighing stirrer, characterized in that, include: The mixing tank assembly includes a mixing tank (1) and a stirring paddle (2). The bottom center of the mixing tank is recessed inward to form a positioning part (12) with an internal cavity (11). The stirring paddle is sleeved on the positioning part. The magnetic levitation motor temperature control assembly includes a heat exchange plate (3) whose upper surface abuts against the bottom of the mixing tank, a magnetic levitation motor (4) located at the center of the heat exchange plate and with one end extending into the cavity for levitizing the stirring paddle by electromagnetic force and for driving the stirring paddle to rotate, and a ceramic cooling plate array (5) located on the lower surface of the heat exchange plate for heating or cooling the mixing tank. The base (6) and the weighing sensor (7) installed between the magnetic levitation motor and the base for real-time measurement of the total mass of the mixing tank assembly and the magnetic levitation motor temperature control assembly. The control system is electrically connected to the magnetic levitation motor, the ceramic cooling array, and the weighing sensor.

2. A magnetically levitated temperature-controlled weighing stirrer according to claim 1, characterized in that: It also includes a heat dissipation component (8), which is disposed below the ceramic cooling chip array and is used to dissipate heat generated at the hot end of the ceramic cooling chip array.

3. A magnetically levitated temperature-controlled weighing stirrer according to claim 2, characterized in that, The ceramic cooling chip array (5) is arranged in a two-stage series structure, including a first ceramic cooling chip array (51), a heat-conducting plate (52), and a second ceramic cooling chip array (53). The cold end of the first ceramic cooling chip array abuts against the lower surface of the heat exchange plate, and the hot end abuts against the upper surface of the heat-conducting plate; The cold end of the second ceramic cooling chip array abuts against the lower surface of the heat-conducting plate, and the hot end abuts against the heat dissipation component.

4. A magnetically levitated temperature-controlled weighing stirrer according to claim 2, characterized in that, The ceramic cooling chip array (5) adopts a single-stage structure. The cold end of the ceramic cooling chip array abuts against the lower surface of the heat exchange plate, and the hot end abuts against the upper surface of the heat-conducting plate. The lower surface of the heat-conducting plate abuts against the heat dissipation component.

5. A magnetically levitated temperature-controlled weighing stirrer according to any one of claims 1-4, characterized in that: The stirring paddle (2) includes an annular magnet (21) and a covered blade (22) covering the outside of the annular magnet (21). The covered blade is provided with an annular inner surface (221) adapted to the outer periphery of the positioning part, and a plurality of evenly distributed blades (222) are provided on the outer periphery.

6. A magnetically levitated temperature-controlled weighing stirrer according to any one of claims 1-4, characterized in that, The control system includes: A temperature detection module is used to obtain the temperature of the material inside the mixing tank (1); A PWM voltage regulation module is electrically connected to the ceramic cooling array and is used to adjust the power supply voltage of the ceramic cooling array through pulse width modulation. The PID control module is electrically connected to the temperature detection module and the PWM voltage regulation module. It is used to obtain the temperature deviation through the material temperature and the preset temperature, and based on the temperature deviation, drive the PWM voltage regulation module to adjust the cooling or heating power of the ceramic cooling array through the PID control algorithm.

7. A magnetically levitated temperature-controlled weighing stirrer according to claim 6, characterized in that: The temperature detection module includes a temperature sensor (9), which is installed on the outside of the heat exchange plate (3) and is used to collect the temperature of the outer wall of the stirring tank (1). The control system is also used to obtain the temperature of the heat exchange plate (3) based on the temperature of the outer wall of the mixing tank (1) through a heat conduction model. If the temperature of the heat exchange plate is less than a preset threshold, the upper limit of the output duty cycle of the PWM voltage regulation module is limited.

8. A control method for a magnetically levitated temperature-controlled weighing stirrer, applied to the magnetically levitated temperature-controlled weighing stirrer according to any one of claims 1-6, characterized in that, Specifically, the steps include the following: Real-time monitoring of material temperature inside the mixing tank; The temperature deviation is obtained based on the material temperature and the preset temperature. The PID parameters are adjusted in real time based on the temperature deviation to obtain the current setpoint. The actual operating current of the ceramic cooling array is obtained, and the current deviation is obtained based on the actual operating current and the current setting value. Based on the current deviation, a PWM voltage regulation command is output through a PI control algorithm; The power supply voltage of the ceramic cooling array is adjusted based on the PWM voltage regulation command to control its cooling or heating power.

9. A control method for a magnetically levitated temperature-controlled weighing stirrer according to claim 8, characterized in that, The real-time acquisition of the material temperature inside the mixing tank specifically includes the following steps: The temperature data set is formed by repeatedly collecting the temperature of the material inside the mixing tank. Based on the temperature difference between any two adjacent materials in the temperature data set, if the difference is less than or equal to a preset difference threshold, the temperature data set is determined to be valid data. The temperature data set is then subjected to low-pass filtering to obtain the real-time material temperature. If the difference is greater than a preset difference threshold, the temperature data set is determined to be invalid data, the temperature data set is deleted, and the above steps are repeated until the real-time material temperature is obtained.

10. A control method for a magnetically levitated temperature-controlled weighing stirrer according to claim 8, characterized in that, Also includes: Obtain the stirring speed and / or material weight of the magnetic levitation temperature-controlled weighing stirrer; Based on the stirring speed and / or the material weight, the PID parameters are optimized, and based on the optimized PID parameters, the current setpoint is corrected.

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