High and low temperature testing machine temperature control system heated by pipeline type electric heating pipe

Abstract

The invention relates to the technical field of high and low temperature testing machines, and discloses a high and low temperature testing machine temperature control system heated by a pipeline type electric heating pipe, which comprises a testing cabin, a temperature control module, a heating module and a refrigeration module, the refrigeration module adopts a double-compressor cascade refrigeration module, the temperature control module adopts a fuzzy self-adaptive PID control module, and the heating module adopts a pipeline type electric heating pipe. And a temperature adjusting mechanism is also arranged in the test cabin. Through the fuzzy self-adaptive PID control technology, the fuzzy set theory and traditional PID are combined, the intelligence and precision of temperature control are greatly improved, the temperature control system error and the error change rate are fuzzified, the parameters Kp, Ki and Kd are set according to the fuzzy rule, the system can automatically adjust the control strategy according to the change of the external environment, and the temperature control accuracy is improved. The adaptive capacity to complex working conditions is enhanced, the temperature control mode of cold and hot confrontation enables temperature adjustment to be finer, the temperature control precision is guaranteed, and a stable and reliable temperature environment is provided for testing.

Description

Technical Field

[0001] This invention relates to the field of high and low temperature testing equipment technology, specifically a temperature control system for a high and low temperature testing equipment using a pipe-type electric heating element. Background Technology

[0002] High and low temperature test chambers are widely used in semiconductor, electronics, materials and other fields. They are important reliability test chambers used to conduct alternating or constant high and low temperature tests on electrical products, materials and components. They are used to verify the adaptability of various components and products to different temperature environments, thereby ensuring the reliability, adaptability and safety of components and products in different harsh temperature environments. They are one of the main basic testing methods for verifying and improving product quality and reliability. High and low temperature test chambers play an indispensable role in scientific research and testing.

[0003] In the existing technology, the refrigerant used in high and low temperature testing machines is prone to corroding the test components and has limited cooling capacity and insufficient cooling effect. Summary of the Invention

[0004] The purpose of this invention is to provide a temperature control system for a high and low temperature testing machine with a pipe-type electric heating tube, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: This invention relates to a temperature control system for a high and low temperature testing machine using a pipe-type electric heating element, comprising a testing chamber, a temperature control module, a heating module, and a cooling module. The heating module is a pipe-type electric heating element, the cooling module is a dual-compressor cascade cooling module, and the temperature control module is a fuzzy adaptive PID control module.

[0006] The tubular electric heating module also includes a tubular electric heating tube and an ultra-high temperature protection unit. The tubular electric heating tube has an electric heating container inside, and the electric heating container has a specific heat exchange channel inside, which is spiral in shape. One end of the tubular electric heating tube has an input port. The ultra-high temperature protection unit includes a temperature sensor, a comparator, and a relay. The temperature sensor, comparator, and relay are sequentially fixedly installed on the surface of the tubular electric heating tube. The output terminal of the sensor is connected to the input terminal of the comparator, and the output terminal of the comparator is connected to the input terminal of the relay.

[0007] The dual-compressor cascade refrigeration module also includes a primary compressor and a secondary compressor. A condenser is located between the primary compressor and the secondary compressor, and both ends of the condenser are connected to the pipelines of the primary compressor and the secondary compressor, respectively. Spring shock absorbers are fixedly installed on both the primary compressor and the secondary compressor, and the pipelines of the refrigeration module are provided with arc bends.

[0008] The fuzzy adaptive PID control module includes a fuzzy controller and a PID controller, with the output of the fuzzy controller connected to the input of the PID controller.

[0009] By adopting the above technical solution, this solution integrates a pipeline electric heating module, a dual-compressor cascade refrigeration module, and a fuzzy adaptive PID control module to form a highly efficient and coordinated temperature control system. The pipeline electric heating module can heat efficiently, while the dual-compressor cascade refrigeration module can achieve deep cooling. Together with the fuzzy adaptive PID control module, the temperature control system can flexibly adjust the temperature within a wide temperature range. This not only broadens the applicable temperature range of the testing machine but also lays the foundation for subsequent precise temperature control and improved heating and cooling rates. At the same time, the spring vibration dampers on the first and second stage compressors reduce operating vibration, extend the life of the testing machine, and improve the overall stability and reliability of the system.

[0010] The test chamber is also equipped with a temperature regulation mechanism, which is a fan used to circulate and agitate the air inside the test chamber.

[0011] By adopting the above technical solution, the fan in the test chamber acts as a temperature regulation mechanism, which can circulate and stir the air in the chamber, making the temperature distribution in the chamber more uniform and reducing the temperature gradient. This avoids the problem of inconsistent local temperatures in the test chamber, ensures that all parts of the test component are in the same temperature environment, improves the fairness and accuracy of the test, makes the test results more reflective of the performance of the test component under actual temperature conditions, and improves the reliability of the test data.

[0012] Furthermore, the inlet on the tubular electric heating tube is used for the introduction of a low-temperature fluid medium, which travels in a specific heat exchange channel. The electric heating container heats the low-temperature fluid medium to remove the high-temperature heat energy generated during the operation of the electric heating element. The temperature sensor is used to monitor the temperature of the tubular electric heating tube, and the relay is used to cut off the power supply to the tubular electric heating tube.

[0013] By adopting the above technical solution, the working mechanism of the pipeline electric heating tube and the role of the ultra-high temperature protection unit are clarified, which brings significant benefits. The low-temperature fluid medium flows in the spiral heat exchange channel, which can fully absorb the heat of the electric heating element, improve heating efficiency, and accelerate the heating rate. The ultra-high temperature protection unit can cut off the power supply in time when the temperature is too high through real-time monitoring by temperature sensors, judgment by comparators, and relay action, so as to avoid damage to the electric heating tube due to dry burning, ensure the safe operation of the testing machine, and protect the test piece in the test chamber from high temperature damage.

[0014] Furthermore, the dual-compressor cascade refrigeration module also includes a refrigeration pipe, a cold bypass pipe, and a hot bypass pipe, and the refrigeration pipe, cold bypass pipe, and hot bypass pipe are connected to the fuzzy adaptive PID control module for control.

[0015] The above technical solution, which connects the refrigeration pipe, cold bypass pipe, and hot bypass pipe with the fuzzy adaptive PID control module, is key to improving the flexibility and accuracy of temperature control. Under PID control, these three pipes can flexibly adjust the flow rate and direction of the refrigerant, and can quickly respond to temperature changes in the test chamber, replenishing or reducing cooling or heating in a timely manner to ensure that the temperature remains stable at the set value. This effectively avoids large temperature fluctuations, improves the response speed and accuracy of low-temperature control, and meets the requirements of test scenarios with high temperature stability.

[0016] Furthermore, the dual-compressor cascade refrigeration module is also equipped with a refrigeration capacity adjustment unit, a gas-liquid bypass adjustment unit, and an evaporation temperature adjustment unit. The refrigeration capacity adjustment unit is used to adjust the refrigerant flow rate of the refrigeration unit, the gas-liquid bypass adjustment unit is used to adjust the gas-liquid bypass flow rate, and the evaporation temperature adjustment unit is used to adjust the evaporation temperature. The dual-compressor cascade refrigeration module also includes a dry compressed air supply component. The dry compressed air supplied by the dry compressed air supply component serves as a medium, and its dew point temperature is lower than the minimum operating temperature of the testing machine.

[0017] By adopting the above technical solution, the adjustability of cooling capacity, gas-liquid bypass flow rate and evaporation temperature allows the refrigeration system to accurately output cooling capacity according to different low-temperature requirements, avoiding energy waste. The use of dry compressed air as a medium with a dew point temperature lower than the minimum operating temperature of the test machine fundamentally eliminates ice blockage, ensuring the stability of low-temperature operation. It also avoids the corrosion problems that may be caused by traditional refrigerants, and broadens the applicability of the test machine to the tested components.

[0018] Furthermore, the fuzzy adaptive PID control module is used to combine fuzzy set theory with traditional PID control. The fuzzy controller fuzzifies the system error e and the error change rate ec in their respective domains. Based on fuzzy rules, it establishes three tables for querying the changes of Kp, Ki, and Kd through fuzzy inference. It automatically tunes the Kp, Ki, and Kd parameters of the PID controller according to changes in the external environment, and the temperature control process adopts a cold-heat confrontation form.

[0019] The above-mentioned technical solution, which combines fuzzy set theory with traditional PID control, greatly improves the intelligence and accuracy of temperature control. By fuzzifying the temperature control system error and error change rate, and tuning the parameters Kp, Ki, and Kd according to fuzzy rules, the system can automatically adjust the control strategy according to changes in the external environment, enhancing its adaptability to complex working conditions. The temperature control method of hot and cold confrontation allows for more precise temperature regulation, effectively reducing temperature fluctuations, ensuring temperature control accuracy, providing a stable and reliable temperature environment for testing, and improving the accuracy of test data.

[0020] Furthermore, the cooling capacity regulating unit includes a solenoid valve and a flow sensor. The flow sensor is used to monitor the refrigerant flow in each pipe in real time and feed it back to the fuzzy adaptive PID control module. The solenoid valve is used to control the fuzzy adaptive PID control module.

[0021] By adopting the above technical solution, the solenoid valve and flow sensor of the cooling capacity regulation unit form a closed-loop control system. The flow sensor monitors the refrigerant flow in real time and feeds it back to the fuzzy adaptive PID control module. The module then precisely controls the flow through the solenoid valve, realizing the dynamic adjustment of the refrigerant flow. This not only accurately supplies cooling capacity according to actual cooling demand, avoiding excess or insufficient cooling capacity and improving cooling efficiency, but also reduces energy consumption, lowers operating costs, and ensures the stability of the cooling effect.

[0022] The connection ends of the refrigeration pipe, cold bypass pipe, and hot bypass pipe are all equipped with sealing gaskets at the connection ends with the compressor and condenser. The pipes in the refrigeration module are made of copper pipes with gas shielded welding.

[0023] By adopting the above technical solution, the sealing gaskets and gas-protected welding of copper pipes at the connection ends of refrigeration pipes bring significant advantages in sealing and corrosion prevention. The sealing gaskets enhance the sealing performance of the pipe connections, effectively preventing refrigerant leakage and ensuring the normal pressure and refrigeration efficiency of the refrigeration system. The gas-protected welding of copper pipes avoids the generation of oxides on the inner wall of the pipes, which is a problem in traditional welding. This prevents oxides from damaging the refrigeration system and compressor, extends the service life of the refrigeration module, reduces the failure rate of the testing machine, and reduces maintenance costs.

[0024] Furthermore, it also includes a waste heat recovery and reuse unit, which includes a waste heat exchanger and a heat storage container. The input end of the waste heat exchanger is connected to the waste heat output end of the pipe-type electric heating tube and the waste heat output end of the condenser in the dual-compressor cascade refrigeration module, respectively. The output end of the waste heat exchanger is connected to the input end of the heat storage container, and the output end of the heat storage container is connected to the input port of the pipe-type electric heating tube through a preheating pipe.

[0025] By adopting the above technical solution, excess heat not fully utilized by the heating element during heating, as well as waste heat dissipated by the condenser during cooling, can be collected. Previously, this heat was simply lost; now, it is stored in a heat storage container through a waste heat exchanger, essentially turning waste into treasure. When supplying a low-temperature medium to the heating element later, this recovered heat is used for preheating, ensuring the medium has a base temperature from the start. This eliminates the need for the electric heating container to heat from zero, directly reducing the workload of electric heating and saving on electricity costs. Furthermore, the heat utilization is more thorough, resulting in a more energy-efficient system overall.

[0026] Furthermore, the waste heat exchanger is used to absorb the redundant heat from the operation of the pipe-type electric heating tube and the waste heat emitted by the condenser; the heat storage container is used to store the heat collected by the waste heat exchanger; and the preheating pipe is used to conduct the heat in the heat storage container to the low-temperature fluid medium introduced at the inlet, thereby preheating the low-temperature fluid medium.

[0027] Using the above technical solution, the heat storage container can store heat and use it whenever preheating is needed, without having to wait for the waste heat to be generated. This provides high flexibility. The low-temperature medium is preheated before entering the electric heating tube, which is equivalent to preheating. After entering the spiral heat exchange channel, the electric heating container only needs to add a little heat to reach the target temperature, significantly increasing the heating speed. Moreover, the heat is recycled during this process, without consuming additional energy. This improves heating efficiency and avoids the problems of waste heat and excessively high ambient temperature that were previously possible.

[0028] Furthermore, the waste heat recovery and reuse unit also includes a flow control valve, which is installed on the preheating pipe and is connected to a fuzzy adaptive PID control module. The fuzzy adaptive PID control module controls the opening and closing degree of the flow control valve to adjust the preheating heat according to the real-time temperature of the pipe-type electric heating tube and the initial temperature of the low-temperature fluid medium.

[0029] By adopting the above technical solution, the flow control valve is connected to the fuzzy adaptive PID controller, which prevents blind preheating. For example, if the heating element is already quite hot, or the initial temperature of the low-temperature medium is not low, the PID controller can adjust the valve to a smaller or even closed position based on these real-time conditions to avoid overheating. If the medium is particularly cold, the valve can be opened wider to deliver more preheating heat. In this way, the preheating is sufficient and not wasteful. It will not cause temperature runaway due to excessive preheating, nor will it affect the heating efficiency due to insufficient preheating. This ensures the stability of the entire temperature control system, further optimizes energy consumption, and makes the operation more intelligent and reliable.

[0030] The present invention has the following beneficial effects: (1) The present invention has a spiral heat exchange channel in the electric heating container inside the pipe-type electric heating tube. When the low-temperature fluid medium is introduced from the inlet, it will flow along the spiral channel. This channel design increases the contact area and contact time between the fluid and the electric heating container, which can make the heat generated by the electric heating container more fully transferred to the fluid medium, thereby rapidly increasing the temperature of the low-temperature fluid medium. Compared with the traditional heating method, this design can make the heating more uniform and efficient. It not only broadens the range of achievable high temperatures, but also greatly improves the rate of heating and cooling. This means that the testing machine can achieve a large temperature change in a shorter time, shorten the testing cycle, improve testing efficiency, and meet the product testing needs that require different temperature change rates.

[0031] (2) This invention provides a strong guarantee for the safe operation of the test machine by designing an ultra-high temperature protection unit. The ultra-high temperature protection unit consists of a temperature sensor, a comparator and a relay. The temperature sensor monitors the temperature of the tubular electric heating tube in real time and transmits the monitored temperature signal to the comparator. The comparator compares the received temperature signal with the preset safe temperature value. When the monitored temperature exceeds the safe value, the comparator sends a signal to the relay, and the relay will cut off the power supply to the tubular electric heating tube in time to prevent the electric heating tube from being damaged due to ultra-high temperature. In addition, this protection mechanism also avoids the damage to the test piece in the test chamber that may be caused by the electric heating tube overheating, as well as the safety hazards caused. This multi-protection design makes the test machine safer and more reliable when operating at high temperature, reduces the failure rate of the test machine, and extends the service life of the test machine.

[0032] (3) This invention effectively avoids ice blockage by using a dual-compressor cascade refrigeration module, ensuring stable operation at low temperatures. The first-stage compressor uses a medium-low temperature refrigerant with an evaporation temperature as low as -40°C of the test machine. The second-stage compressor uses a low-temperature refrigerant, which can meet the even lower temperature requirements of the test machine. At the same time, the first-stage system provides condensation conditions for the second-stage system, ensuring that the low-temperature refrigerant in the second-stage system is fully condensed and avoiding excessively high pressure ratios. More importantly, the system medium uses dry compressed air, which can ensure a sufficiently low dew point temperature, preventing ice blockage from the source. This is in stark contrast to the limited refrigeration capacity and susceptibility to ice blockage in existing technologies, allowing the test machine to operate continuously and stably in low-temperature environments, providing a reliable environmental guarantee for various low-temperature tests, and greatly improving the continuity and accuracy of the tests.

[0033] (4) In this invention, a condenser is set between the primary compressor and the secondary compressor, and the two are connected by a pipe, so that the refrigerant can circulate and exchange heat efficiently between the two compressors. At the same time, the working cooperation of the cooling capacity adjustment unit, the gas-liquid bypass adjustment unit and the evaporation temperature adjustment unit can accurately adjust the refrigerant flow rate, the gas-liquid bypass flow rate and the evaporation temperature according to actual needs. In the low temperature working state, the refrigerant flow rate and flow direction are adjusted by PID to adjust the three-way flow of the refrigeration pipe, the cold bypass pipe and the hot bypass pipe, so as to achieve automatic constant temperature of the working chamber. These designs enable the test machine to easily reach lower temperatures and the cooling effect is stable, which enhances the test machine's ability to test various products in extreme low temperature environments and meets the strict requirements of low temperature testing in more fields.

[0034] (5) The present invention uses dry compressor air as the medium, replacing the traditional potentially corrosive refrigerant, eliminating the risk of corrosion of the test piece by the refrigerant from the source. At the same time, the low-temperature fluid medium introduced into the pipeline electric heating tube flows in a specific heat exchange channel and has a reasonable isolation design between it and the test piece, so it will not directly contact the test piece, further protecting the test product. This is especially important for testing products such as semiconductors and electronic components that are sensitive to corrosion, ensuring that the test piece will not be affected by corrosion during the test process, thus achieving the fairness and accuracy of the test and reducing the economic losses caused by damage to the test piece due to corrosion.

[0035] (6) The fuzzy adaptive PID control module of this invention combines fuzzy set theory with traditional PID control, significantly improving the temperature control stability and accuracy of the temperature control system. The fuzzy controller fuzzifies the error tester e and the error change rate tester ec in their respective domains of discourse. Based on fuzzy rules, a lookup table is established through fuzzy inference to automatically tune the three parameters Kp, Ki, and Kd of the PID controller. This control method can adjust the control parameters in real time according to changes in the external environment. Compared with traditional PID control, it has stronger adaptability. In the temperature control process, a cold-heat confrontation mode is adopted. When the temperature deviates from the set value, the system can react quickly and accurately control the temperature within the set range by adjusting the working state of the heating and cooling modules. This ensures the stability of the temperature in the test chamber, reduces temperature fluctuations, improves the accuracy of test data, and provides precise temperature conditions for the performance testing of products under different temperature environments.

[0036] (7) In the refrigeration module, the present invention, through effective energy regulation measures such as cooling capacity regulation, gas-liquid bypass regulation and evaporation temperature regulation, enables the test machine to maintain a constant temperature at any low temperature point without heating balance, and the operating power can be reduced to half, which significantly reduces energy consumption. The spring shock absorbers installed on the first and second compressors in the dual-compressor cascade refrigeration module, as well as the use of increased arc bends in the refrigeration pipes, reduce the vibration of the test machine during operation and reduce the risk of deformation and leakage of the pipes due to vibration and temperature changes. The refrigeration module pipes adopt copper pipe gas protection welding method, which avoids the damage to the refrigeration system and compressor caused by oxides generated on the inner wall of the copper pipe by traditional welding, extends the service life of the test machine, and reduces the failure rate. In addition, safety protection mechanisms such as the ultra-high temperature protection unit also reduce the number of times the test machine has to be shut down for maintenance due to failure, and reduce maintenance costs.

[0037] (8) Through the optimized design and collaborative work of each module, this invention greatly enhances the overall reliability of the testing machine and extends its service life. The reasonable layout and connection method of the dual-compressor cascade refrigeration module, as well as the use of spring shock absorbers, reduce the vibration and wear of the compressor during operation and improve the stability of the refrigeration system. The spiral-shaped specific heat exchange channel design of the pipeline electric heating tube makes the heating process more uniform and efficient, reducing the local overheating of the electric heating tube. Combined with the ultra-high temperature protection unit, the electric heating tube is further protected. The fuzzy adaptive PID control module ensures the stability of the system operation and reduces the wear and tear on the components of the testing machine caused by temperature fluctuations. In addition, the use of copper pipe gas protection welding and sealing gaskets in the refrigeration pipeline improves the sealing of the pipeline connection and avoids problems such as refrigerant leakage. Through the combined effect of these designs, the testing machine can maintain stable performance in long-term and frequent high and low temperature testing, reduce the occurrence of failures, extend the service life of the test, and provide users with more lasting use value.

[0038] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of the overall system of the present invention; Figure 2 This is a flowchart illustrating the heating and over-temperature protection process of the present invention. Figure 3 This is a flowchart of the refrigeration system control process of the present invention; Figure 4 This is a flowchart of the temperature control logic of the present invention. Figure 5 This is a flowchart of the waste heat recovery and reuse unit of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Please see Figures 1-5As shown, the present invention provides a technical solution: a temperature control system for a high and low temperature testing machine with a pipe-type electric heating tube, comprising a testing chamber, a temperature control module, a heating module, and a cooling module. The heating module adopts a pipe-type electric heating module, the cooling module adopts a dual-compressor cascade cooling module, the temperature control module adopts a fuzzy adaptive PID control module, and the interior of the testing chamber is also provided with a temperature regulating mechanism, which is a fan used to circulate and stir the air in the testing chamber.

[0043] It should be noted that this solution integrates a pipe-type electric heating module, a dual-compressor cascade refrigeration module, and a fuzzy adaptive PID control module to form a highly efficient and collaborative temperature control system. The pipe-type electric heating module can heat efficiently, while the dual-compressor cascade refrigeration module can achieve deep cooling. Together with the fuzzy adaptive PID control module, the temperature control system can flexibly adjust the temperature within a wide temperature range, which not only broadens the applicable temperature range of the testing machine but also lays the foundation for subsequent precise temperature control and improved heating and cooling rates.

[0044] In addition, the fan inside the test chamber acts as a temperature regulation mechanism, which can circulate and agitate the air inside the chamber, making the temperature distribution more uniform and reducing temperature gradients. This avoids the problem of inconsistent local temperatures inside the test chamber, ensuring that all parts of the test component are in the same temperature environment, improving the fairness and accuracy of the test, making the test results more reflective of the performance of the test component under actual temperature conditions, and improving the reliability of the test data.

[0045] Based on the above scheme, the present invention provides the following embodiments. Example 1

[0046] Please see Figure 1 and Figure 2 As shown, the present invention provides an embodiment of the technical solution: the tubular electric heating module further includes a tubular electric heating tube and an ultra-high temperature protection unit. The tubular electric heating tube has an electric heating container inside, and the electric heating container has a specific heat exchange channel inside, and the specific heat exchange channel is spirally arranged. One end of the tubular electric heating tube has an input port. The ultra-high temperature protection unit includes a temperature sensor, a comparator, and a relay. The temperature sensor, comparator, and relay are sequentially fixedly installed on the surface of the tubular electric heating tube. The output end of the sensor is signal-connected to the input end of the comparator, and the output end of the comparator is signal-connected to the input end of the relay.

[0047] Preferably, the inlet on the tubular electric heating tube is used for the introduction of a low-temperature fluid medium, which travels in a specific heat exchange channel. The electric heating container heats the low-temperature fluid medium to remove the high-temperature heat energy generated during the operation of the electric heating element. The temperature sensor is used to monitor the temperature of the tubular electric heating tube, and the relay is used to cut off the power supply to the tubular electric heating tube.

[0048] In this embodiment, the working mechanism of the pipe-type electric heating tube and the role of the ultra-high temperature protection unit are clearly defined, bringing significant benefits. The low-temperature fluid medium flows in the spiral heat exchange channel, which can fully absorb the heat of the electric heating element, improve heating efficiency, and accelerate the heating rate. The ultra-high temperature protection unit can cut off the power supply in time when the temperature is too high through real-time monitoring by temperature sensors, judgment by comparators, and relay action, to avoid damage to the electric heating tube due to dry burning, ensure the safe operation of the testing machine, and protect the test piece in the test chamber from high temperature damage. Example 2

[0049] Please see Figure 1 and Figure 3 As shown, based on the above embodiment 1, the present invention provides an embodiment technical solution: the dual-compressor cascade refrigeration module further includes a primary compressor and a secondary compressor, a condenser is provided between the primary compressor and the secondary compressor, and the two ends of the condenser are respectively connected to the pipelines of the primary compressor and the secondary compressor. Spring shock absorbers are fixedly installed on both the primary compressor and the secondary compressor, and the pipeline of the refrigeration module is provided with arc bends.

[0050] Preferably, the dual-compressor cascade refrigeration module further includes a refrigeration pipe, a cold bypass pipe, and a hot bypass pipe, and the refrigeration pipe, cold bypass pipe, and hot bypass pipe are controlled and connected to a fuzzy adaptive PID control module. The dual-compressor cascade refrigeration module is also provided with a refrigeration capacity adjustment unit, a gas-liquid bypass adjustment unit, and an evaporation temperature adjustment unit. The refrigeration capacity adjustment unit is used to adjust the refrigerant flow rate of the refrigeration unit, the gas-liquid bypass adjustment unit is used to adjust the gas-liquid bypass flow rate, and the evaporation temperature adjustment unit is used to adjust the evaporation temperature. The dual-compressor cascade refrigeration module also includes a dry compressed air supply component. The dry compressed air provided by the dry compressed air supply component serves as a medium, and its dew point temperature is lower than the minimum operating temperature of the testing machine.

[0051] It should be noted that the adjustability of cooling capacity, gas-liquid bypass flow rate, and evaporation temperature allows the refrigeration system to accurately output cooling capacity according to different low-temperature requirements, avoiding energy waste. The use of dry compressed air as a medium with a dew point temperature lower than the minimum operating temperature of the test machine fundamentally eliminates ice blockage, ensuring the stability of low-temperature operation. It also avoids the corrosion problems that may be caused by traditional refrigerants, thus broadening the applicability of the test machine to the tested components.

[0052] Preferably, the control connection between the refrigeration pipe, cold bypass pipe, hot bypass pipe and fuzzy adaptive PID control module is the key to improving the flexibility and accuracy of temperature control. Under PID control, these three pipes can flexibly adjust the flow rate and direction of the refrigerant, and can quickly respond to the temperature changes in the test chamber, timely replenish or reduce the cooling and heating capacity, and ensure that the temperature is stable at the set value. This effectively avoids large temperature fluctuations, improves the response speed and accuracy of low temperature control, and meets the test scenarios with high requirements for temperature stability.

[0053] In this embodiment, the cooling capacity adjustment unit includes a solenoid valve and a flow sensor. The flow sensor is used to monitor the refrigerant flow in each pipe in real time and feed it back to the fuzzy adaptive PID control module. The solenoid valve is used to control the fuzzy adaptive PID control module. The connection ends of the refrigeration pipe, cold bypass pipe, and hot bypass pipe are all equipped with sealing gaskets at the connection ends with the compressor and condenser. The pipes in the refrigeration module are made of copper pipes with gas shielded welding.

[0054] Preferably, the solenoid valve and flow sensor of the cooling capacity regulation unit form a closed-loop control system. The flow sensor monitors the refrigerant flow in real time and feeds it back to the fuzzy adaptive PID control module. The module then precisely controls the flow through the solenoid valve, realizing the dynamic regulation of the refrigerant flow. This not only accurately supplies cooling capacity according to actual cooling demand, avoiding excess or insufficient cooling capacity and improving cooling efficiency, but also reduces energy consumption, lowers operating costs, and ensures the stability of the cooling effect.

[0055] It should be noted that the sealing gaskets and gas-protected welding of copper pipes at the connection ends of refrigeration pipes bring significant advantages in sealing and corrosion prevention. The sealing gaskets enhance the sealing of the pipe connection, effectively preventing refrigerant leakage and ensuring the normal pressure and refrigeration efficiency of the refrigeration system. The gas-protected welding of copper pipes avoids the formation of oxides on the inner wall of the pipes that are produced by traditional welding, preventing oxides from damaging the refrigeration system and compressor, extending the service life of the refrigeration module, reducing the failure rate of the testing machine, and reducing maintenance costs. Example 3

[0056] Please see Figure 1 and Figure 4As shown, based on the above embodiments 1 and 2, the present invention provides an embodiment technical solution: the fuzzy adaptive PID control module includes a fuzzy controller and a PID controller. The output terminal of the fuzzy controller is connected to the input terminal of the PID controller. Preferably, the fuzzy adaptive PID control module is used to combine fuzzy set theory with traditional PID control. The fuzzy controller fuzzifies the system error e and the error change rate ec in their respective domains. According to fuzzy rules, it establishes three tables for querying the changes of Kp, Ki, and Kd through fuzzy inference. It automatically tunes the Kp, Ki, and Kd parameters of the PID controller according to changes in the external environment. The temperature control process adopts a cold-heat counteraction form. The domain of the system error e is [-5,5], and the domain of the error change rate ec is [-2,2]. The system error e and the error change rate ec are divided into seven fuzzy levels: negative large, negative medium, negative small, zero, positive small, positive medium, and positive large. The fuzzy rules are formulated based on a large amount of experimental data and expert experience to ensure the accuracy and reliability of fuzzy inference, so as to achieve precise tuning of PID parameters.

[0057] In this implementation scheme, fuzzy adaptive PID control technology combines fuzzy set theory with traditional PID, greatly improving the intelligence and accuracy of temperature control. By fuzzifying the temperature control system error and error change rate, and tuning the Kp, Ki, and Kd parameters according to fuzzy rules, the system can automatically adjust the control strategy according to changes in the external environment, enhancing its adaptability to complex working conditions. The temperature control method of hot and cold confrontation allows for more precise temperature regulation, effectively reducing temperature fluctuations, ensuring temperature control accuracy, providing a stable and reliable temperature environment for testing, and improving the accuracy of test data. Example 4

[0058] Please see Figure 1 and Figure 5 As shown, based on the above embodiments 1, 2, and 3, the present invention provides an embodiment technical solution: it further includes a waste heat recovery and reuse unit, the waste heat recovery and reuse unit includes a waste heat heat exchanger and a heat storage container, the input end of the waste heat heat exchanger is respectively connected to the waste heat output end of the pipe-type electric heating tube and the waste heat output end of the condenser in the dual-compressor cascade refrigeration module, the output end of the waste heat heat exchanger is connected to the input end of the heat storage container, and the output end of the heat storage container is connected to the input port of the pipe-type electric heating tube through a preheating pipe.

[0059] It's important to note that the waste heat recovery and reuse unit can collect excess heat that wasn't fully utilized by the heating element during heating, as well as waste heat dissipated from the condenser during cooling. Previously, this heat was simply lost; now, it's stored in a heat storage container via a waste heat exchanger, essentially turning waste into treasure. When supplying the heating element with a low-temperature medium, this recovered heat is used for preheating, ensuring the medium has a base temperature from the start. This eliminates the need for the electric heating container to heat from zero, directly reducing the workload of the electric heating system and definitely saving on electricity costs. Furthermore, the heat utilization is more thorough, resulting in a more energy-efficient overall system. In this embodiment, the waste heat exchanger is used to absorb redundant heat from the operation of the tubular electric heating tube and waste heat emitted by the condenser. The heat storage container is used to store the heat collected by the waste heat exchanger. The preheating pipe is used to conduct the heat in the heat storage container to the low-temperature fluid medium introduced at the inlet, preheating the low-temperature fluid medium. The heat storage container can store heat, allowing for immediate use when preheating is needed, without waiting for the waste heat to be generated, thus offering high flexibility. The low-temperature medium is preheated before entering the electric heating tube, essentially warming it up. After entering the spiral heat exchange channel, the electric heating container only needs to add a little heat to reach the target temperature, significantly increasing the heating speed. Furthermore, the heat is recycled during this process, without additional energy consumption, improving heating efficiency and avoiding the previous problems of waste heat waste and potentially excessively high ambient temperatures. The waste heat recovery and reuse unit also includes a flow control valve, which is installed on the preheating pipe and connected to a fuzzy adaptive PID control module. The control module adjusts the preheating heat by controlling the opening and closing of the flow control valve based on the real-time temperature of the pipe-type electric heating element and the initial temperature of the low-temperature fluid medium.

[0060] Furthermore, once the flow control valve is connected to the fuzzy adaptive PID controller, preheating is no longer done blindly. For example, if the heating element is already quite hot, or the initial temperature of the low-temperature medium is not low, the PID controller can adjust the valve to a smaller or even closed position based on these real-time conditions to avoid overheating. If the medium is particularly cold, the valve can be opened wider to deliver more preheating heat. In this way, preheating is sufficient without being wasteful. It will not cause temperature runaway due to excessive preheating, nor will it affect heating efficiency due to insufficient preheating. This ensures the stability of the entire temperature control system, further optimizes energy consumption, and makes the operation more intelligent and reliable.

[0061] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A temperature control system for a high and low temperature testing machine using a pipe-type electric heating element, characterized in that: It includes a test chamber, a temperature control module, a heating module, and a cooling module. The heating module adopts a pipe-type electric heating module, the cooling module adopts a dual-compressor cascade cooling module, and the temperature control module adopts a fuzzy adaptive PID control module. The tubular electric heating module also includes a tubular electric heating tube and an ultra-high temperature protection unit. The tubular electric heating tube has an electric heating container inside, and the electric heating container has a specific heat exchange channel inside, which is spiral in shape. One end of the tubular electric heating tube has an input port. The ultra-high temperature protection unit includes a temperature sensor, a comparator, and a relay. The temperature sensor, comparator, and relay are sequentially fixedly installed on the surface of the tubular electric heating tube. The output end of the sensor is connected to the input end of the comparator, and the output end of the comparator is connected to the input end of the relay. The dual-compressor cascade refrigeration module also includes a primary compressor and a secondary compressor. A condenser is provided between the primary compressor and the secondary compressor, and both ends of the condenser are connected to the pipelines of the primary compressor and the secondary compressor, respectively. Spring shock absorbers are fixedly installed on both the primary compressor and the secondary compressor. The pipelines of the refrigeration module are provided with arc bends. The fuzzy adaptive PID control module includes a fuzzy controller and a PID controller, with the output of the fuzzy controller connected to the input of the PID controller. The test chamber is also equipped with a temperature regulation mechanism, which is a fan used to circulate and agitate the air inside the test chamber.

2. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 1, characterized in that, The inlet on the tubular electric heating tube is used to introduce a low-temperature fluid medium, which travels in a specific heat exchange channel. The electric heating container heats the low-temperature fluid medium to remove the high-temperature heat energy generated during the operation of the electric heating element. The temperature sensor is used to monitor the temperature of the tubular electric heating tube, and the relay is used to cut off the power supply to the tubular electric heating tube.

3. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 1, characterized in that, The dual-compressor cascade refrigeration module further includes a refrigeration pipe, a cold bypass pipe, and a hot bypass pipe, and the refrigeration pipe, cold bypass pipe, and hot bypass pipe are connected to a fuzzy adaptive PID control module.

4. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 3, characterized in that, The dual-compressor cascade refrigeration module is further equipped with a refrigeration capacity adjustment unit, a gas-liquid bypass adjustment unit, and an evaporation temperature adjustment unit. The refrigeration capacity adjustment unit is used to adjust the refrigerant flow rate of the refrigeration unit, the gas-liquid bypass adjustment unit is used to adjust the gas-liquid bypass flow rate, and the evaporation temperature adjustment unit is used to adjust the evaporation temperature. The dual-compressor cascade refrigeration module also includes a dry compressed air supply component. The dry compressed air supplied by the dry compressed air supply component serves as a medium, and its dew point temperature is lower than the minimum operating temperature of the testing machine.

5. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 1, characterized in that, The fuzzy adaptive PID control module combines fuzzy set theory with traditional PID control. The fuzzy controller fuzzifies the system error e and the error change rate ec within their respective domains of discourse. Based on fuzzy rules, it establishes three tables for querying the changes in Kp, Ki, and Kd through fuzzy inference. It automatically tunes the Kp, Ki, and Kd parameters of the PID controller according to changes in the external environment, and the temperature control process adopts a cold-heat counteraction method.

6. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 4, characterized in that, The cooling capacity regulation unit includes a solenoid valve and a flow sensor. The flow sensor is used to monitor the refrigerant flow in each pipe in real time and feed it back to the fuzzy adaptive PID control module. The solenoid valve is used to control the fuzzy adaptive PID control module. The connection ends of the refrigeration pipe, cold bypass pipe, and hot bypass pipe are all equipped with sealing gaskets at the connection ends with the compressor and condenser. The pipes in the refrigeration module are made of copper pipes with gas protection welding.

7. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 1, characterized in that, It also includes a waste heat recovery and reuse unit, which includes a waste heat exchanger and a heat storage container. The input end of the waste heat exchanger is connected to the waste heat output end of the pipe-type electric heating tube and the waste heat output end of the condenser in the dual-compressor cascade refrigeration module, respectively. The output end of the waste heat exchanger is connected to the input end of the heat storage container. The output end of the heat storage container is connected to the input port of the pipe-type electric heating tube through a preheating pipe.

8. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 7, characterized in that, The waste heat exchanger is used to absorb the redundant heat from the operation of the pipe-type electric heating tube and the waste heat emitted by the condenser. The heat storage container is used to store the heat collected by the waste heat exchanger. The preheating pipe is used to conduct the heat in the heat storage container to the low-temperature fluid medium introduced at the inlet, and to preheat the low-temperature fluid medium.

9. The temperature control system for a high and low temperature testing machine with pipe-type electric heating tube heating according to claim 7, characterized in that, The waste heat recovery and reuse unit also includes a flow control valve, which is installed on the preheating pipe and is connected to a fuzzy adaptive PID control module. The fuzzy adaptive PID control module controls the opening and closing degree of the flow control valve to adjust the preheating heat according to the real-time temperature of the pipe-type electric heating tube and the initial temperature of the low-temperature fluid medium.

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