Control method and system for high-low temperature fast temperature change

Abstract

The application provides a control method and system for high-low temperature fast temperature change, which is used for quickly switching or linear slope control of medium temperature of a test sample, and the method comprises the following steps: independently heating test medium in an energy storage loop to a preset high temperature and keeping the energy storage loop isolated from a main circulation loop in advance, the main circulation loop being communicated with the test sample; when fast temperature rising is performed, the energy storage loop is instantaneously communicated with the main circulation loop through a switching device, so that high-temperature medium in the energy storage loop is introduced into the main circulation loop, and the medium temperature at the inlet of the test sample is stepwisely increased; when linear temperature rising or linear temperature falling is performed, a heat regulating device arranged in the main circulation loop is used to continuously adjust the medium temperature in a feedback control mode according to a preset temperature change slope until the target temperature is reached. The application is used to solve the problem of how to simultaneously realize high temperature rising rate and high-precision linear temperature change control of test medium under the premise of avoiding compressor impact.

Description

Technical Field

[0001] This invention relates to the field of high and low temperature rapid temperature change testing, and in particular to a control method and system for high and low temperature rapid temperature change. Background Technology

[0002] Currently, high and low temperature performance testing of test samples such as PTC heaters, water pumps, and water valves typically employs a circulating medium test bench. This bench uses a refrigeration system and heating devices to regulate the temperature of the medium, thus raising or lowering the sample's temperature. Existing test benches mostly use a direct-drive evaporator method, where the evaporator of the refrigeration system directly exchanges heat with the test medium to lower its temperature; heating relies on an electric heater to directly heat the circulating medium. This architecture is generally feasible under conventional temperature change rate requirements. However, as testing standards increasingly demand higher temperature change rates, existing solutions reveal significant shortcomings: during rapid switching between high and low temperatures, the direct-drive evaporator method severely impacts the compressor, leading to a shortened compressor lifespan and increased control difficulty; simultaneously, rapid heating relies on a high-power heater directly heating the medium, which, limited by heater power and medium heat capacity, makes it difficult to achieve ultra-high heating rates, and the temperature control accuracy during linear temperature changes is insufficient, failing to meet high-precision testing requirements.

[0003] Therefore, how to achieve ultra-high-speed switching and high-precision linear slope control of the test medium temperature while avoiding compressor shock and ensuring system stability is a technical problem that urgently needs to be solved in this field. Currently, there is a lack of a testing method and device that can simultaneously achieve rapid heating and linear temperature change, while avoiding compressor shock and improving system stability.

[0004] Therefore, it is necessary to propose a rapid temperature change testing scheme for high and low temperatures to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a control method and system for rapid temperature changes at high and low temperatures, in order to solve the problem of how to achieve both high heating rate and high-precision linear temperature change control of the test medium while avoiding compressor impact.

[0006] Firstly, a control method for rapid temperature changes at high and low temperatures is provided, used for rapid switching of the medium temperature or linear slope control of the test sample, including: Choose one of the following steps based on the temperature change requirements: The high-temperature medium in the energy storage circuit, which has been independently heated to a preset high temperature and is isolated from the main circulation circuit, is instantaneously introduced into the main circulation circuit connected to the test sample through a switching device, so that the medium temperature at the inlet of the test sample rises in a step. The temperature of the medium is continuously adjusted according to a preset heating or cooling slope by means of a thermal regulation device installed in the main circulation loop, until the target temperature is reached.

[0007] The cascade oil chiller unit controls the amount of refrigerant injected through an electronic expansion valve to precisely regulate the evaporation temperature.

[0008] Secondly, a controller is provided for a control system for rapid temperature changes at high and low temperatures. The control system includes a main circulation loop connected to a test sample, an energy storage loop connected to the main circulation loop via a switching device, and a thermal regulation device disposed in the main circulation loop. The controller includes: a storage unit for storing a computer program; and a processing unit for executing the computer program to achieve the following steps: The energy storage circuit is controlled to independently heat the test medium therein to a preset high temperature, while keeping it isolated from the main circulation circuit; When rapid heating is required, the switching device is controlled to instantly connect the energy storage circuit and the main circulation circuit, so that the high-temperature medium in the energy storage circuit is introduced into the main circulation circuit, so that the medium temperature at the inlet of the test sample rises in a step. When linear heating or cooling is required, the thermal regulation device is controlled to continuously adjust the medium temperature according to a preset temperature change slope in a feedback control manner until the target temperature is reached.

[0009] Thirdly, a control system for rapid temperature changes at high and low temperatures is provided, used for rapid switching of the medium temperature or linear slope control of the test sample, including: The main circulation loop, which is connected to the test specimen, is used to provide the test specimen with a circulating test medium; The energy storage circuit is connected to the main circulation circuit via a switching device, and is used to independently store and heat the test medium to a preset high temperature, while remaining isolated from the main circulation circuit. A thermal regulation device, disposed in the main circulation loop, is used to heat or cool the test medium in the main circulation loop; and, The controller is connected to the switching device and the thermal regulation device respectively. The controller is used to: control the switching device to instantaneously connect the energy storage circuit and the main circulation circuit when performing rapid heating, so that the high temperature medium in the energy storage circuit is introduced into the main circulation circuit, so that the medium temperature at the inlet of the test sample rises in a step; or control the thermal regulation device to continuously adjust the medium temperature according to the preset temperature change slope in a feedback control mode when performing linear heating or linear cooling, until the target temperature is reached.

[0010] Fourthly, a terminal device is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the method described in the first aspect.

[0011] Fifthly, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0012] The beneficial effects of this invention are as follows: This invention integrates "instantaneous switching of pre-stored energy" and "feedback linear regulation" into a single control method, selectively executing one based on temperature change requirements. This effectively solves the technical problems of existing technologies, which struggle to simultaneously achieve rapid heating and high-precision linear temperature change, and are prone to compressor damage. Specifically: When rapid heating is required, the medium in the pre-heated and isolated energy storage circuit is directly invoked and instantaneously introduced into the main circulation circuit via a switching device, achieving a step-like increase in medium temperature (heating rate can reach over 120℃ / min). This completely avoids the power surge and response delay caused by relying on a high-power heater to directly heat the circulating medium. When linear heating or cooling is required, the medium temperature is continuously adjusted according to a preset temperature change slope via a thermal regulation device in the main circulation circuit using feedback control. This ensures high-precision linear temperature change of ±2℃ while avoiding the severe impact on the compressor during high-low temperature switching in the evaporator direct-drive mode, significantly improving system stability and equipment lifespan. Furthermore, the two modes can be flexibly switched according to temperature change requirements without interference, simultaneously meeting the testing requirements for ultra-high heating rates and high-precision linear temperature change.

[0013] Furthermore, this invention monitors the deviation between the actual cooling rate and the preset rate during the linear cooling process. When the actual cooling rate is lower than the preset rate, the cascade oil chiller unit is switched from cold storage mode to direct cooling mode. This switch significantly reduces the volume of silicone oil involved in heat exchange, effectively solving the problem of insufficient cooling rate in the latter half of the traditional cold storage mode. This ensures that a linear cooling capacity of ≥10℃ / min can be maintained throughout the entire cooling range, further improving the reliability and rate consistency of the cooling process.

[0014] Furthermore, this invention achieves independent control of multi-channel parallel testing by configuring an independent main circulation loop branch for each test sample and utilizing variable frequency pumps, flow meters, and pressure gauges on each branch to independently control the flow rate and pressure at the inlet of each sample. This allows the same test bench to simultaneously support multiple different types of samples, with no interference between the temperature changes in each channel, thus significantly improving testing efficiency and reducing equipment investment costs. It is particularly suitable for simultaneous comparative testing scenarios involving diverse components such as PTC heaters, water pumps, and water valves. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart of a control method for rapid temperature changes at high and low temperatures according to an embodiment of the present invention. Figure 2 This is a schematic flowchart illustrating another embodiment of the control method for rapid temperature changes at high and low temperatures according to the present invention. Figure 3 This is a schematic flowchart illustrating another embodiment of the control method for rapid temperature changes at high and low temperatures according to the present invention. Figure 4 This is a schematic flowchart illustrating another embodiment of the control method for rapid temperature changes at high and low temperatures according to the present invention. Figure 5 This is a schematic flowchart illustrating another embodiment of the control method for rapid temperature changes at high and low temperatures according to the present invention. Figure 6 This is a test curve diagram of one embodiment of the present invention; Figure 7 This is a schematic structural block diagram of a control system for rapid temperature changes at high and low temperatures according to an embodiment of the present invention. Figure 8 This is a schematic structural diagram of a control system for rapid temperature changes at high and low temperatures, according to an embodiment of the present invention. Figure 9 This is a schematic structural diagram of a low-temperature cold source system according to an embodiment of the present invention; Figure 10 This is a topological diagram of a computer-readable storage medium disclosed in this invention. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0017] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] Example 1: As Figure 1 As shown, this embodiment 1 provides a control method for rapid temperature change at high and low temperatures (hereinafter referred to as "control method" or "method"), which is used to rapidly switch the medium temperature or control the linear slope of the test sample, so as to solve the problem in the prior art that it is difficult to balance rapid heating and high-precision linear temperature change, and the compressor is easily damaged.

[0019] The method in this embodiment 1 includes: Step 101. Receive temperature change commands from the user or the host computer, and parse the temperature change commands to obtain preset temperature change parameters. The temperature change command includes at least the temperature change direction, target temperature, and temperature change rate parameters.

[0020] Step 102. Check whether the liquid level of the test medium in the main circulation loop and the temperature of the test medium in the energy storage loop are within the preset range, and check whether the communication status of the switching device and the thermal regulation device is normal; if the self-test passes, enter the standby state and wait to execute the selected temperature change step.

[0021] Step 103. Select either rapid heating or linear temperature change steps based on the temperature change requirements: (1) Rapid heating: The high-temperature medium in the energy storage circuit, which has been independently heated to a preset high temperature and is isolated from the main circulation circuit, is introduced into the main circulation circuit connected to the test sample through a switching device, so that the medium temperature at the inlet of the test sample rises in a stepwise manner. Before the test begins, a heater (such as an electric heating element) installed in the energy storage circuit preheats the test medium (ethylene glycol solution with a freezing point of -60℃) stored in the energy storage circuit. A temperature sensor monitors the medium temperature in real time. When the temperature reaches 110℃~130℃ (preferably around 120℃), heating automatically stops and the circuit enters a heat preservation state, ensuring the energy storage circuit always maintains the preset high-temperature medium. Simultaneously, the switching device (such as a valve) between the energy storage circuit and the main circulation circuit remains closed, ensuring complete isolation of the media in the two circuits. The main circulation circuit circulates an initial low-temperature medium (such as around -40℃) and is connected to the test sample. By pre-storing the high-temperature medium in an independent energy storage circuit and precisely controlling the temperature, the power surge and response delay caused by relying on a high-power heater to directly heat the circulating medium during rapid heating are avoided. Maintaining the heat preservation state ensures the temperature stability of the high-temperature medium, providing a reliable heat source for subsequent step heating. Strict isolation between circuits prevents the high-temperature medium from prematurely mixing into the main circulation circuit, ensuring the accuracy of the initial test conditions. In this way, the above measures together achieve pre-storage and rapid standby of the test medium temperature, laying the physical foundation for subsequent ultra-high-speed heating of ≥120℃ / min, while reducing the instantaneous power requirement of the system and improving the safety and controllability of the equipment.

[0022] (2) Linear heating or linear cooling: The temperature of the medium is continuously adjusted according to the preset heating or cooling slope by means of the thermal regulation device set in the main circulation loop in the feedback control mode until the target temperature is reached.

[0023] Among them, the step of "instantly introducing the main circulation loop connected to the test sample through the switching device" in the rapid heating step (1) includes: issuing a valve switching command through the PLC controller so that the switching device can be opened within a preset time so as to directly connect the outlet of the energy storage loop with the inlet of the main circulation loop.

[0024] Step (1) The operation of "introducing the high-temperature medium in the energy storage circuit into the main circulation circuit" in rapid heating includes: based on the pressure difference between the energy storage circuit and the main circulation circuit, controlling the high-temperature medium in the energy storage circuit to replace the original low-temperature medium in the main circulation circuit by displacement, and making the low-temperature medium flow back to the energy storage circuit or discharge, thereby realizing the instantaneous jump of the inlet medium temperature of the test sample from low temperature (e.g. -40℃) to high temperature (e.g. 120℃).

[0025] It should be understood that the precise PLC control of the switching device ensures the timely and synchronous introduction of the high-temperature medium, avoiding the bottleneck of heating power limiting the heating rate in traditional heating methods. The pressure difference-driven displacement method allows for rapid medium replacement without additional power, significantly shortening the mixing time and enabling the sample inlet temperature to rise in a step-like manner within a very short time (measured ≥120℃ / min). The design for the reflux or discharge of the low-temperature medium prevents excessive mixing of hot and cold media from reducing heating efficiency, further improving the rapid heating response speed and temperature stability. These measures collectively achieve ultra-high-speed thermal shock to the test sample, meeting the stringent testing standards for heating rate, while simultaneously reducing system energy consumption and hardware wear.

[0026] like Figure 2 As shown, the operation of "continuously adjusting the medium temperature according to the preset heating slope by means of a thermal regulation device set in the main circulation loop in a feedback control manner" in step (2) linear heating includes: Step 201. The PLC controller outputs a control signal to the electric heater according to the set heating slope (e.g., ≥120℃ / min), so that the electric heater adjusts its output power based on the control signal, thereby achieving a controlled rise in the medium temperature.

[0027] Step 202. Real-time acquisition of the deviation between the medium temperature value fed back by the temperature sensor installed in the main circulation loop and the target value, so as to dynamically correct the control signal, so that the medium temperature rises continuously according to the heating slope and reaches the target temperature. In this step, a closed-loop control algorithm (such as PID) can be used to dynamically correct the control signal, so that the medium temperature strictly follows the preset heating slope to rise continuously, and finally stabilizes to reach the target temperature.

[0028] In this embodiment 1, the PLC controller and the electric heater work together to form a closed-loop mapping between the set heating rate and the actual power output, avoiding the temperature overshoot or lag phenomenon of traditional on / off heating. The temperature deviation is collected in real time and the control signal is dynamically corrected to ensure that the medium temperature can rise linearly with a preset slope throughout the entire heating range, with a control accuracy of ±2℃. This feedback adjustment mechanism can automatically compensate for external disturbances (such as changes in ambient temperature and fluctuations in medium flow), greatly improving the robustness and test repeatability of the system, providing a precise and reproducible linear heating environment for the test specimen, and meeting the requirements of high-precision performance testing.

[0029] like Figure 3 As shown, the specific operation of "continuously adjusting the medium temperature according to the preset cooling slope by means of a thermal regulation device set in the main circulation loop in a feedback control manner" in step (2) linear cooling includes: Step 301. Start the cascade oil cooler unit in advance and cool its internal medium to the set temperature.

[0030] Step 302. Control the PLC controller to adjust the opening of the proportional valve according to the set cooling slope, so as to control the heat exchange efficiency between the main circulation loop and the oil chiller.

[0031] Step 303. Dynamically adjust the opening of the proportional valve according to the deviation between the actual cooling rate and the preset rate, so that the actual cooling rate approaches the preset rate, so that the medium temperature continuously decreases according to the cooling slope and reaches the target temperature. The actual cooling rate is the calculation result of the PLC based on the real-time temperature sensor feedback value.

[0032] In this embodiment 1, firstly, the cascade oil chiller unit (composed of a primary R404a jet cooling stage and a secondary R23 unipolar cooling stage) is pre-started to cool the internal low-temperature silicone oil medium to a set temperature (e.g., below -60°C), putting the oil chiller unit into a cold storage standby state. Then, the PLC controller adjusts the opening of the proportional valve according to the set cooling slope (e.g., ≥10°C / min), thereby changing the heat exchange efficiency between the test medium (ethylene glycol solution) in the main circulation loop and the silicone oil inside the oil chiller unit, achieving preliminary control of the medium cooling rate. Next, the PLC calculates the actual cooling rate based on the real-time temperature sensor feedback value and compares it with the preset rate. The opening of the proportional valve is dynamically corrected based on the deviation between the two, so that the actual cooling rate continuously approaches the preset rate, thereby ensuring that the medium temperature continuously decreases according to the set cooling slope and finally reaches the target temperature (e.g., -40°C).

[0033] This setup ensures sufficient cooling capacity by pre-starting the cascade oil chiller and cooling it to a temperature far below the target temperature, providing a stable heat sink for linear cooling. By using a proportional valve to adjust the heat exchange efficiency instead of directly starting and stopping the compressor, the impact on the compressor caused by traditional direct cooling methods is avoided, significantly extending equipment life. The PLC controller performs closed-loop correction based on the deviation between the actual cooling rate and the preset rate, which can compensate for rate deviations caused by factors such as load changes and media characteristic fluctuations in real time, ensuring that the cooling process strictly follows a linear slope (control accuracy up to ±2℃), thereby solving the problem of cooling rate attenuation in the latter half. Furthermore, this feedback mechanism can automatically adjust the proportional valve opening according to actual needs without manual intervention, improving the automation level of testing and the repeatability of results.

[0034] Continue with Figure 3 To clarify, the operations following step 303 also include a chiller operating mode switching step: Step 304. During the linear cooling process, when the actual cooling rate is lower than the preset rate, the cascade oil chiller unit is switched from the cold storage mode to the direct cooling mode.

[0035] It should be understood that during the dynamic correction process in step 303, the PLC continuously monitors the deviation between the actual cooling rate and the preset rate. If the proportional valve opening has been adjusted to the maximum or the actual cooling rate is still lower than the preset rate after correction (e.g., insufficient cooling capacity in the latter half), the PLC issues a mode switching command to switch the cascade oil chiller unit from the cold storage mode (i.e., all 200L of silicone oil participates in the circulating heat exchange, with large heat capacity and stable cooling but limited rate) to the direct cooling mode (i.e., only a small amount of silicone oil participates in the heat exchange, with small heat capacity and high heat exchange efficiency). This significantly increases the heat exchange per unit time, allowing the actual cooling rate to quickly rise above the preset rate, ensuring that the linear slope requirement is maintained throughout the entire cooling range.

[0036] By introducing a dual-mode switching mechanism for cold storage and direct cooling, the technical challenge of slow cooling rate reduction in the latter half of the cooling process in traditional cold storage mode is effectively solved. When insufficient cooling rate is detected, the system automatically switches to direct cooling mode, utilizing the efficient heat exchange characteristics of a small amount of silicone oil to quickly replenish the cooling capacity, ensuring that the cooling rate is always at least at a preset value (e.g., 10℃ / min). This guarantees the integrity and reliability of linear cooling across the entire temperature range. This step requires no manual intervention; the PLC makes intelligent decisions based on actual operating conditions. This extends the lifespan of the compressor and its refrigeration system (normal operation in cold storage mode reduces impact) and provides additional cooling capacity under extreme conditions, significantly improving the adaptability of the equipment and testing efficiency.

[0037] In the above embodiment 1, as Figure 4 As shown, the control method also includes a mode switching step: Step 104. After rapid heating is completed, the switching device is controlled by the PLC controller to return to the off state, so that the energy storage circuit and the main circulation circuit are re-isolated, and the circuit is switched to linear temperature change mode or heat preservation mode according to the test requirements. The heat preservation mode includes the PLC controller controlling the electric heater to maintain the temperature deviation between the medium in the main circulation circuit and the target temperature within ±0.5℃.

[0038] Once the rapid heating step is completed and the inlet medium temperature of the test sample rises stepwise to the target high temperature (e.g., 120°C), the PLC controller issues a command to control the switching device (e.g., an electric valve) to return to the closed state, thus physically isolating the energy storage circuit from the main circulation circuit again, preventing temperature overshoot or runaway caused by continuous injection of high-temperature medium. At the same time, the next step requirement is determined according to the preset test procedure: if linear heating (e.g., continuing to increase the temperature) or linear cooling (e.g., decreasing at a rate of 10°C / min from a high temperature) is required, the system switches to linear temperature change mode, and the thermal regulation device takes over the closed-loop temperature control; if the current high temperature needs to be maintained for durability or stability testing, the system switches to heat preservation mode, and the electric heater maintains a constant medium temperature. Therefore, by promptly disconnecting the energy storage circuit from the main circulation circuit, interference from the high-temperature medium after rapid heating on subsequent precise temperature changes is avoided, ensuring the independence and controllability of the linear temperature change or heat preservation process. At the same time, the PLC automatically judges and switches to the corresponding mode, enabling the same test bench to continuously complete multiple test items such as thermal shock, linear scanning, and constant temperature aging without manual intervention, improving testing efficiency and automation level, and preventing equipment damage or test data deviation caused by misoperation.

[0039] In the above embodiment 1, the control method further includes a multi-channel independent control step: Each test specimen is equipped with an independent main circulation loop branch. Variable frequency pumps, flow meters, and pressure gauges installed on each branch independently control the flow rate and pressure at the inlet of each specimen. Each branch is connected in parallel to the main circulation pipeline. A PLC independently controls the speed of each variable frequency pump and the opening of its regulating valve, achieving independent closed-loop regulation of the inlet flow rate (0–40 L / min) and pressure (0–4 bar) for each specimen. Simultaneously, different test conditions (such as different flow rate, pressure, and temperature sequences) can be set for each branch without interference. This enables parallel and independent control of three test channels, allowing simultaneous testing of multiple samples of the same or different types with different parameters, significantly improving testing efficiency and equipment utilization. The flow and pressure control accuracy of each channel can reach ±0.5%FS and 0.1bar, meeting the requirements of high-precision comparative testing. Independent adjustment of each branch avoids coupling interference between channels, and the switching of the operating conditions of one channel will not affect the stability of other channels. It is especially suitable for synchronous comparative or aging testing scenarios of various components such as PTC heaters, water pumps, and water valves, which can reduce testing costs and shorten the R&D cycle.

[0040] Building upon Embodiment 1 above, to further achieve a rapid, step-like cooling of the inlet medium temperature of the test sample (e.g., instantly dropping from 120°C to -40°C), a cold storage circuit connected to the main circulation loop via a second switching device can be added to the system. This cold storage circuit includes an independent refrigeration unit (such as an auxiliary cascade refrigeration system) and a cryogenic storage tank, used to pre-cool the test medium to a preset low temperature (e.g., -60°C) and maintain isolation. When rapid cooling is required, the controller controls the second switching device to instantly connect the cold storage circuit and the main circulation loop, using the pressure difference to rapidly introduce the cryogenic medium from the cold storage circuit into the main circulation loop to replace the original high-temperature medium, causing a step-like drop in the inlet medium temperature of the sample. This scheme, combined with rapid heating, forms a symmetrical rapid temperature change capability, which can meet more stringent thermal shock testing standards (e.g., instantaneous switching from 120°C to -40°C), while avoiding direct exposure of the compressor to high and low temperature shocks, thus further expanding the application scenarios of the equipment.

[0041] In the aforementioned rapid heating step, due to the large temperature difference between the energy storage circuit and the main circulation circuit, instantaneous connection may cause an overshoot phenomenon in the sample inlet temperature, exceeding the target value. To solve this problem, this embodiment introduces an adaptive adjustment step in the rapid heating step, such as... Figure 5 As shown: Step 501. While the switching device is turned on, the controller collects the rate of change (dT / dt) of the inlet medium temperature of the test sample in real time and compares the rate of change with the preset safety threshold. Step 502. If the rate of change exceeds the threshold, the controller intermittently controls the switching device to turn on and off in pulse width modulation (PWM) mode, so that the high temperature medium is introduced into the main circulation loop in multiple pulses, thereby suppressing temperature overshoot while maintaining rapid overall heating.

[0042] Furthermore, the controller can dynamically adjust the duty cycle of subsequent pulses based on the real-time deviation between the sample inlet temperature and the target temperature, ensuring that the temperature smoothly approaches the target value. This solution significantly improves the temperature control accuracy during rapid heating through software algorithms without adding extra hardware, making it particularly suitable for high-precision test samples sensitive to temperature overshoot, and possessing significant engineering practical value.

[0043] This embodiment 1 provides a control method for rapid temperature changes at high and low temperatures, suitable for rapid switching of medium temperature and linear slope control of test samples such as PTC heaters, water pumps, and water valves. The test medium is an ethylene glycol solution with a freezing point of -60℃. The equipment includes a cascade oil cooling unit and a three-station sample control system. The implementation process of the control method in this embodiment is as follows: 1. System Pre-treatment: Before the test begins, the test medium is preheated by an electric heater installed in the energy storage loop (a 100L or 200L preheating tank). A temperature sensor monitors the medium temperature in real time. Heating stops when the temperature reaches 120℃, and the system enters a heat preservation state, ensuring the energy storage loop maintains a high-temperature medium in standby mode. Simultaneously, the switching valve between the energy storage loop and the main circulation loop remains closed, ensuring complete isolation between the two loops. An initial low-temperature medium (approximately -40℃) circulates in the main circulation loop and is connected to the test sample via a circulating water pump. Furthermore, the cascade oil cooler unit (first-stage R404a jet cooling + second-stage R23 single-stage cooling) is started to cool its internal low-temperature silicone oil medium to below -60℃, putting the oil cooler unit into a cold storage standby state.

[0044] 2. Mode Selection and Parameter Setting: The required temperature change mode and parameters are set via the Siemens PLC: For rapid heating, set the target temperature (e.g., 120℃) and heating rate (≥120℃ / min); for linear heating, set the target temperature and heating slope (e.g., 20℃ / min); for linear cooling, set the target temperature (e.g., -40℃) and cooling slope (≥10℃ / min). The PLC automatically determines the required mode based on the set parameters.

[0045] 3. Rapid Heating Mode (Step-by-Step): When rapid heating is required, the PLC controller issues a valve switching command, causing the switching valve to open within 1 second, directly connecting the energy storage circuit outlet to the main circulation circuit inlet. Utilizing the pressure difference between the energy storage circuit and the main circulation circuit, the 120℃ high-temperature medium in the energy storage circuit rapidly replaces the original -40℃ low-temperature medium in the main circulation circuit through displacement. The replaced low-temperature medium flows back to the energy storage circuit or is discharged from the system. The medium temperature at the inlet of the test sample rises to 120℃ in a step-by-step manner in a very short time, with a heating rate ≥120℃ / min.

[0046] like Figure 8As shown, to achieve rapid step heating, this embodiment is equipped with a compressed air source CA (0~3 bar) to assist in media delivery. The high-temperature liquid tank (i.e., preheating tank 7021, 200L, 60~130℃) is equipped with a high-power electric heater H4 (380V / 38kW) and a level switch, with a safety valve and an exhaust valve at the top. The outlet of the high-temperature liquid tank is connected to the main circulation loop via an impact valve YV4, which is a pneumatic or electric quick-opening valve and is normally closed. When the rapid heating command is issued, the controller first ensures the compressed air source pressure is stable, then instantaneously opens the impact valve YV4. Simultaneously, using the air pressure inside the tank and the pump's thrust, the 120℃ high-temperature ethylene glycol solution is rapidly injected into the inlet of the test piece. At the same time, the original low-temperature medium in the main circulation loop and the high-pressure return liquid generated during the impact process flow through pipelines into the buffer tank HC (80L) for temporary storage. The buffer tank has a balance pipe at the top connected to the high-temperature liquid tank and a one-way valve at the bottom. After the impact action is completed, the impact valve YV4 closes, and the liquid stored in the buffer tank HC slowly flows back to the high-temperature liquid tank through the balance pipe and one-way valve. The heater used during the non-impact phase restores the liquid to the preset temperature in preparation for the next impact. This design of temporary storage during impact and return after impact effectively avoids a sharp drop in temperature caused by direct mixing of hot and cold media, while absorbing pressure shocks and stabilizing the system flow.

[0047] 4. Mode Switching After Rapid Heating: Once rapid heating is complete and the sample inlet temperature stabilizes at 120℃, the PLC-controlled switching valve returns to the closed state, re-isolating the energy storage circuit from the main circulation circuit. According to the preset test procedure, if linear cooling is required (e.g., from 120℃ to -40℃ at a rate of 10℃ / min), the PLC automatically switches to linear temperature change mode; if maintaining 120℃ for durability testing is required, it switches to heat preservation mode, where the electric heater maintains a constant medium temperature.

[0048] 5. Linear Heating Mode (Closed-Loop Feedback): When linear heating is required (e.g., from -40℃ to 120℃ at a rate of 20℃ / min), the PLC controller outputs a control signal to the electric heater according to the set heating slope. The electric heater adjusts its output power based on this signal. Simultaneously, the PLC collects the medium temperature value fed back from the temperature sensor installed in the main circulation loop in real time, calculates the deviation from the target value, and uses a PID algorithm to dynamically correct the control signal, ensuring that the medium temperature strictly follows the preset heating slope and continuously rises until the target temperature of 120℃ is reached. The control accuracy during the linear heating process can reach ±2℃.

[0049] 6. Linear Cooling Mode (Closed-Loop Feedback + Mode Switching): When linear cooling is required (e.g., from 120℃ to -40℃ at 10℃ / min), the PLC first confirms that the cascade oil chiller has been pre-cooled to below -60℃. The PLC adjusts the opening of the proportional valve according to the set cooling slope to control the heat exchange efficiency between the ethylene glycol solution in the main circulation loop and the silicone oil inside the oil chiller. Simultaneously, the PLC calculates the actual cooling rate based on real-time temperature sensor feedback and compares it with the preset rate (10℃ / min). Based on the deviation, the PLC dynamically adjusts the proportional valve opening to make the actual cooling rate approach the preset rate. If, during the cooling process (especially in the latter half), the PLC detects that the proportional valve opening has been adjusted to the maximum but the actual cooling rate continues to be lower than the preset rate, it will automatically switch the cascade oil cooler unit from the cold storage mode (all 200L of silicone oil participates in circulation) to the direct cooling mode (only a small amount of silicone oil participates in heat exchange), significantly improving heat exchange efficiency and causing the cooling rate to recover rapidly. This ensures that the entire cooling range maintains a linear slope of ≥10℃ / min until the medium temperature reaches -40℃. The temperature control accuracy during this process can reach ±2℃.

[0050] 7. Multi-channel independent control: The method in this embodiment supports parallel independent control of three test channels. Each test specimen is configured with an independent main circulation loop branch, and each branch is equipped with a variable frequency pump, electromagnetic flowmeter, pressure sensor, and temperature sensor. The PLC independently adjusts the variable frequency pump speed and regulating valve opening of the corresponding branch according to the flow rate (0–40 L / min) and pressure (0–4 bar) parameters set for each channel, achieving independent closed-loop control of the inlet flow rate and pressure for each specimen, ensuring that the operating conditions of each channel do not interfere with each other.

[0051] 8. Data Acquisition and Protection: Throughout the testing process, the PLC acquires temperature, flow rate, and pressure signals from each channel in real time via remote I / O modules and uploads them to the host computer (LABVIEW / ForceControl). The host computer can display and store temperature-time curves, flow rate-time curves, and pressure-time curves, and supports data report export. Simultaneously, the system has multiple safety protection functions, including overcurrent, short circuit, phase loss, compressor overpressure / overheating, low liquid level, heater dry run-out, and leakage protection, ensuring long-term stable operation of the equipment.

[0052] Figure 6 A complete test cycle curve of low-temperature holding-rapid heating-high-temperature holding-linear cooling-low-temperature holding was demonstrated. The equipment can execute multiple temperature change sequences, that is, realize the automatic switching of heating, holding, and linear cooling. In other words, the control method of this invention enables the test sample to undergo a complete test process of low-temperature isothermal → rapid heating → high-temperature isothermal → linear cooling → low-temperature isothermal, verifying the system's basic capabilities in mode switching, heat preservation, and linear slope control.

[0053] Example 2: As Figure 7 As shown, this embodiment 2 provides a control system 700 for rapid temperature changes at high and low temperatures, used for rapid switching of medium temperature or linear slope control of a test sample. It includes: a main circulation loop 701 connected to the test sample, used to provide circulating test medium to the test sample; an energy storage loop 702 connected to the main circulation loop 701 via a switching device 703, used to independently store and heat the test medium to a preset high temperature, and kept isolated from the main circulation loop 701; a thermal regulation device 704 disposed in the main circulation loop, used to heat or cool the test medium in the main circulation loop 701; and a controller 705 connected to the switching device 703 and the thermal regulation device 704, respectively. The controller 705 includes a storage unit 7051 for storing a computer program; and a processing unit 7052 for executing the computer program to achieve the following steps: controlling the energy storage circuit to independently heat the test medium therein to a preset high temperature and keeping it isolated from the main circulation circuit; when rapid heating is required, controlling the switching device to instantaneously connect the energy storage circuit and the main circulation circuit, so that the high-temperature medium in the energy storage circuit is introduced into the main circulation circuit, so that the medium temperature at the inlet of the test sample rises in a step; when linear heating or linear cooling is required, controlling the thermal regulation device to continuously adjust the medium temperature according to a preset temperature change slope in a feedback control manner until the target temperature is reached.

[0054] Specifically, in combination Figure 8 and Figure 9 The control system 700 is centered around a plate heat exchanger, which is connected to the low-temperature cold source system 800 and the main circulation loop 701. The main circulation loop 701 consists of three parallel independent branches. Each branch is equipped with a variable frequency pump (variable frequency pumps M1, M2, and M3, used to drive the medium circulation), an electromagnetic flowmeter (electromagnetic flowmeters L1, L2, and L3), a pressure sensor (pressure sensor P1, P2, and P3, used to measure the inlet pressure of the sample being tested), and a temperature sensor (temperature sensor T1, T2, and T3). The inlet end of each branch is connected in parallel to the hot-side outlet manifold E0 of the plate heat exchanger E, and the outlet end is connected in parallel to the hot-side inlet manifold E1 of the plate heat exchanger E. The cold side of the plate heat exchanger E is connected to the silicone oil circulation pipeline of the cascade chiller unit. In addition, a total temperature sensor is installed on the hot side inlet E1 and outlet manifold E0 of the plate heat exchanger E to monitor the medium temperature on both sides of the plate heat exchanger.

[0055] To achieve rapid heating, the system includes an 80L buffer tank HC and a 200L high-temperature liquid tank, serving as the core components of the energy storage loop 702. The bottom of the buffer tank HC is connected to the high-temperature liquid tank, and both have a gas balance pipe at their top for balancing the gas and liquid paths. The bottom outlet of the high-temperature liquid tank is connected via a pipe to the main supply valve of the main circulation loop 701. This pipe is equipped with an electrically controlled switching valve (normally closed) to control the connection between the energy storage loop 702 and the main circulation loop 701. The high-temperature liquid tank contains an electric heater and a temperature sensor to independently heat the test medium (ethylene glycol solution) to a preset high temperature (110℃~130℃, typical value 120℃) and maintain it at that temperature. The return port of the high-temperature liquid tank is connected via a valve to the main return pipe of the main circulation loop 701. This pipe is equipped with impact valves YV2, YV3, and YV4 to prevent the low-temperature medium in the main circulation loop from flowing back into the high-temperature liquid tank. When rapid heating is required, the PLC controller issues a command to open the switching valve. The high-temperature ethylene glycol solution, preheated to 120°C in the high-temperature liquid tank, is rapidly injected into the main circulation circuit due to the pressure difference between the energy storage circuit and the main circulation circuit. At the same time, the original low-temperature medium in the main circulation circuit is replaced back to the buffer tank HC through the return liquid pipeline, and then flows into the high-temperature liquid tank. This avoids the low-temperature medium from directly rushing into the high-temperature liquid tank and lowering the temperature of the high-temperature liquid tank, thereby achieving a step increase in the inlet medium temperature of the test sample.

[0056] Additionally, on the cold side (E2-E3) of plate heat exchanger E, there are silicone oil supply and return lines from the cascade chiller unit (i.e., low-temperature cold source system 800). A proportional regulating valve is installed on the silicone oil supply line, with its opening controlled by the PLC to adjust the heat exchange efficiency; a manual shut-off valve is installed on the silicone oil return line. All sensors and actuators in the entire prototype control system are connected to the Siemens PLC controller via remote I / O modules to achieve signal acquisition and command issuance.

[0057] The main circulation loop includes a buffer tank HC, which is a closed pressure vessel with an internal diaphragm or air bladder, or a hollow structure, connected to a nitrogen pressurization port or exhaust valve at the top. The buffer tank can absorb pressure pulsations in the pipeline (caused by changes in the variable frequency pump speed or valve switching), stabilizing the system pressure; during rapid heating, the pressure shock generated during the high-temperature medium displacement process is absorbed by the buffer tank, preventing pipeline vibration; simultaneously, it acts as an expansion vessel, accommodating the volume change caused by the thermal expansion of the medium. Figure 8 As shown, for example, during a 2-minute high-temperature impact period, impact valves YV3 and YV4 are open, while impact valves YV1 and YV2 are closed. The liquid flows in the direction of the green path in the diagram. The liquid that returns from the impact is pre-stored in the buffer tank HC. After the impact action is completed, it flows back to the high-temperature liquid tank (preheating tank 7021) to restore the impact temperature during the non-impact phase.

[0058] An impact valve YV2 (a dedicated switching valve for rapid heating) is installed on the connecting pipeline between the outlet of the high-temperature liquid tank (i.e., preheating tank 7021) and the main circulation loop's main liquid supply pipeline. This valve is used to trigger rapid heating: when the PLC issues a command, the impact valve YV2 instantly opens fully. Utilizing the pressure difference between the preheating tank and the main circulation loop (the preheating tank is under positive pressure, while the main circulation loop is under negative pressure at the pump inlet), the high-temperature medium is injected into the main circulation loop at high speed, achieving a step-like temperature change. The impact valve YV2 is designed for rapid full opening to avoid throttling that would reduce the temperature rise rate.

[0059] The main circulation loop also includes solenoid valves (MV1, MV2, and MV3), which are installed between the outlet of the variable frequency pump and the inlet of the test sample in each of the three test branches. These valves are controlled by a PLC to allow for independent start and stop of each channel. During rapid heating or linear temperature change, any channel can be opened or closed independently according to testing requirements without affecting others. For example, if only channel 1 needs heating, only solenoid valve MV1 is opened, while other channels remain closed or maintain their original operating conditions. The main circulation loop also includes a safety valve 7022, installed at the top of the preheating tank (EXP VESSEL) and at the highest point of the main circulation loop pipeline. The set pressure is slightly higher than the system's maximum operating pressure (e.g., 5 bar). When the medium expands due to heat or a valve switching malfunction causes a sudden pressure rise, the safety valve automatically opens to release pressure, protecting the pipeline and heat exchanger.

[0060] The main circulation loop also includes an exhaust valve (not shown in the diagram, but typically located at the top of the preheating tank and the highest point of the pipeline) and an overflow pipe. The exhaust valve automatically or manually vents air from the system. After adding new media or after a long period of inactivity, the exhaust valve is opened to release gas, preventing cavitation and flow meter measurement errors. The overflow pipe connects the overflow port at the top of the preheating tank to the drain. During rapid heating, if the high-temperature medium displaces back into the preheating tank, causing the liquid level to become too high, the excess medium is discharged through the overflow pipe, preventing abnormal pressure inside the tank. The insulation layer of the main circulation loop wraps around the preheating tank, high-temperature pipelines, and the ethylene glycol side of the plate heat exchanger to reduce heat loss and ensure minimal temperature loss when the high-temperature medium reaches the sample during rapid heating. The thickness of the insulation material is designed based on the maximum operating temperature (120℃) and energy-saving requirements.

[0061] In the above embodiment 2, the thermal regulation device 704 is a functional module for heating or cooling the medium, and is composed of the following two parts working together: (1) Heating section: namely, the electric heaters (H1, H2, H3) in the main circulation loop.

[0062] (2) Cooling section: including cascade oil cooler (generating low-temperature silicone oil below -60℃), plate heat exchanger (for heat exchange between ethylene glycol and silicone oil) and proportional control valve F1 (controlling silicone oil flow rate). Its working principle is as follows: the PLC adjusts the opening of the proportional valve according to the set cooling slope, thereby changing the flow rate of low-temperature silicone oil flowing through the plate heat exchanger, thus controlling the cooling rate of the ethylene glycol solution; at the same time, the actual cooling rate is fed back by the temperature sensor for closed-loop correction.

[0063] The cryogenic cooling system 800 includes a silicone oil circulation loop centered on the cryogenic liquid tank BT. This loop includes an internal circulation pump PUMP1 and a manual shut-off valve HV. The silicone oil supply pump PUMP2, located on the pipeline between the cryogenic liquid tank BT and the plate heat exchanger E, delivers silicone oil to the heat exchanger. PUMP1 is a circulating and stirring pump inside the cryogenic liquid tank BT. The inlet of the internal circulation pump PUMP1 is connected to the bottom of the cryogenic liquid tank BT, and the outlet is connected to a distribution pipe or nozzle inside the tank, ensuring continuous flow of silicone oil within the tank and preventing localized temperature stratification. In cold storage mode, the internal circulation pump runs continuously to ensure a uniform overall temperature of the silicone oil. When switching to direct cooling mode, the pump can be paused to reduce the volume of silicone oil participating in heat exchange, thereby rapidly increasing the cooling rate. Manual shut-off valves HV are installed on the silicone oil return pipeline (from the heat exchanger outlet to the silicone oil tank) and before and after the pump. These valves are used to shut off the oil supply during maintenance and are kept fully open during normal operation. A check valve CV is usually installed on the outlet pipeline of the silicone oil supply pump PUMP2 to prevent silicone oil backflow from damaging the pump seal when the pump is stopped.

[0064] A cryogenic liquid tank BT, located between the evaporator Z1 and the plate heat exchanger E, has its outlet connected to a silicone oil supply pump PUMP2 to store cryogenic silicone oil (freezing point < -75℃) as a cold load buffer. In cold storage mode, the internal circulation pump PUMP1 runs continuously to maintain a uniform temperature within the tank, and the cascade unit cools the silicone oil to below -60℃ and maintains it. In direct cooling mode, the PLC shuts off the internal circulation pump, reducing the volume of silicone oil participating in heat exchange; only a small amount of silicone oil circulates in the pipes and heat exchanger, thereby significantly increasing the cooling rate. An expansion tank 801, located between the suction side of the cryogenic compressor and the evaporator Z1, is used to contain vaporized refrigerant during shutdown. The expansion tank 801 is connected to an exhaust solenoid valve 802.

[0065] The low-temperature cold source system 800 also includes an oil separator OS, oil filters (oil filters G1 and G2), gas-liquid separators (gas-liquid separators Q1 and Q2), a liquid receiver RCV, an electronic expansion valve F2, a solenoid valve F4, a dryer filter DML, and a sight glass SG. The outlet of the oil separator OS is connected to the condenser LN1 (high-temperature stage) and the evaporator-condenser LN2 (low-temperature stage). It contains cyclone separators or filters to separate lubricating oil entrained in the refrigerant vapor and return it to the compressor crankcase, preventing oil from entering the heat exchanger and reducing heat transfer efficiency. During long-term linear cooling operation, the oil separator OS ensures controllable oil film thickness inside the evaporator and condenser, maintaining the stability of the low-temperature stage evaporation temperature of the cascade unit. The liquid receiver RCV is located between the liquid outlet of the condenser LN2 (or the evaporator-condenser) and the electronic expansion valve F2. It stores the condensed liquid refrigerant, balances the refrigerant circulation volume under different operating conditions, and ensures that the expansion valve always has a sufficient liquid column. When the system switches from cold storage mode to direct cooling mode, the evaporation load increases instantly. The liquid receiver RCV can quickly release the stored refrigerant to meet the low temperature requirements and avoid excessively low suction pressure.

[0066] The electronic expansion valve F2 is located between the receiver RCV and the evaporator Z1. The PLC sends stepper motor pulse signals based on the evaporator outlet superheat (calculated by temperature and pressure sensors) or the temperature difference at the silicone oil outlet to precisely adjust the valve opening and control the refrigerant injection volume. During linear cooling, F2 finely regulates the evaporation temperature, stabilizing the silicone oil temperature at the set value (e.g., -60℃); simultaneously, it prevents liquid carryover in the compressor suction, extending the unit's lifespan. The dryer filter DML, containing molecular sieves and a filter screen, adsorbs trace amounts of moisture in the refrigerant and removes impurities. After initial system charging or maintenance, the dryer filter prevents ice and dirt blockage, ensuring the reliable operation of the electronic expansion valve F2. The sight glass SG, installed between the dryer filter DML and the electronic expansion valve F2, is used to observe the refrigerant liquid state (indicating the presence of bubbles or moisture). Operators can use the sight glass SG to determine if the refrigerant charge is appropriate and if the dryer filter is malfunctioning, providing a direct reference for system maintenance. An enthalpy-increasing heat exchanger EC is located between the RCV outlet of the receiver and the enthalpy-increasing electronic expansion valve F3. The enthalpy-increasing electronic expansion valve F3 is also connected to a copper filter ST, which contains molecular sieves and filter screens to adsorb trace amounts of moisture in the refrigerant and filter impurities, preventing ice blockage and dirt blockage.

[0067] Multiple temperature sensors are installed in the control system 700 and the cryogenic cold source system 800, such as inside the preheating tank, at the inlet and outlet of the plate heat exchanger, and at the inlet and outlet of the samples in each test branch. All temperature sensors are PT100 platinum resistance thermometers, which are converted to 4-20mA and sent to the PLC via transmitters. The PLC uses this data to perform: PID control for preheating tank insulation, linear heating closed-loop control, linear cooling rate calculation, and monitoring of the temperature difference between the inlet and outlet of the samples.

[0068] In this embodiment 2, the controller (i.e., the PLC controller) and remote I / O module are specifically configured with a Siemens PLC as the main controller, connected to a remote I / O module (for acquiring signals such as temperature and pressure) via PROFINET or EtherCAT bus. The analog output module controls the power adjustment modules of various valves (controlling heater power) and the frequency converter (controlling pump speed). The digital output module controls MV1-MV3, the switching valve (preheating tank outlet valve), compressor start / stop, and cooling mode switching. The entire control logic completely corresponds to the three operating modes (rapid heating, linear heating, and linear cooling) in embodiment 1.

[0069] It should be noted that the technical solutions of the control system 700 for rapid temperature change at high and low temperatures in this embodiment 2 are the same as those in embodiment 1. Please refer to the description in embodiment 1, and they will not be repeated here.

[0070] Example 3: Example 3 of the present invention also provides a terminal device, which may include a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the above-described... Figures 1-5 The various processes shown in the embodiment of the control method for rapid temperature changes at high and low temperatures can achieve the same technical effect, and will not be described again here to avoid repetition.

[0071] Example 4: Combination Figure 10 As shown, this embodiment 4 also discloses a specific implementation of a computer-readable storage medium 1000. The computer-readable storage medium 1000 can be configured wholly or partially in a physical computer, server, cluster server, or data center.

[0072] In this embodiment 4, the computer-readable storage medium 1000 stores computer program instructions 1001. The computer program instructions 1001 are read and executed by a processor 1002 to perform the steps in the control method for rapid temperature change at high and low temperatures as disclosed in embodiment 1.

[0073] Optionally, the computer-readable storage medium 1000 can be configured as a server, and the server runs on a physical device used to build a private cloud, hybrid cloud, or public cloud. The computer-readable storage medium 1000 can also be configured as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.

[0074] The computer-readable storage medium 1000 is used to store a program, and the processor 1002, upon receiving an execution instruction, executes the control method for rapid temperature changes at high and low temperatures disclosed in Embodiment 1.

[0075] Meanwhile, the processor 1002 disclosed in Embodiment 4 may be an integrated circuit chip with signal processing capabilities. The processor 1002 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor.

[0076] The technical solution of the computer-readable storage medium 1000 disclosed in this embodiment 4 that is the same as that in embodiment 1 and / or embodiment 2 is described in embodiment 1 and / or embodiment 2, and will not be repeated here.

[0077] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0078] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A control method for rapid temperature changes at high and low temperatures, used for rapid switching of the medium temperature or linear slope control of a test sample, characterized in that, This includes selecting one of the following steps based on temperature change requirements: The high-temperature medium in the energy storage circuit, which has been independently heated to a preset high temperature and is isolated from the main circulation circuit, is instantaneously introduced into the main circulation circuit connected to the test sample through a switching device, so that the medium temperature at the inlet of the test sample rises in a step. The temperature of the medium is continuously adjusted according to a preset heating or cooling slope by means of a thermal regulation device installed in the main circulation loop, until the target temperature is reached.

2. The control method according to claim 1, characterized in that, Before selecting one of the following steps based on temperature change requirements, the process also includes: Receive temperature change commands input by the user or issued by the host computer, wherein the temperature change commands include at least the temperature change direction, the target temperature, and the temperature change rate parameters; The temperature change command is parsed to obtain the preset temperature change parameters.

3. The control method according to claim 2, characterized in that, After receiving and parsing the temperature change command, and before selecting to execute the temperature change step, the process also includes: Check whether the liquid level of the test medium in the main circulation loop and the temperature of the test medium in the energy storage loop are within the preset range, and check whether the communication status of the switching device and the thermal regulation device is normal. If the self-test passes, it enters standby mode, waiting to execute the selected temperature change step.

4. The control method according to claim 1, characterized in that, The step of instantaneously introducing the main circulation loop connected to the test sample via the switching device includes: The PLC controller issues a valve switching command to enable the switching device to open within a preset time, thereby directly connecting the outlet of the energy storage circuit to the inlet of the main circulation circuit.

5. The control method according to claim 4, characterized in that, The process of instantaneously introducing the high-temperature medium in the energy storage circuit, which has been independently heated to a preset high temperature and is isolated from the main circulation circuit, into the main circulation circuit connected to the test sample via a switching device includes: Based on the pressure difference between the energy storage circuit and the main circulation circuit, the high-temperature medium in the energy storage circuit is controlled to replace the original low-temperature medium in the main circulation circuit by displacement, and the low-temperature medium is returned to the energy storage circuit or discharged.

6. The control method according to claim 1, characterized in that, The method of continuously adjusting the medium temperature according to a preset heating slope using a thermal regulation device installed in the main circulation loop via feedback control includes: The PLC controller outputs a control signal to the electric heater according to the set heating slope, so that the electric heater adjusts its output power based on the control signal. The deviation between the medium temperature value fed back by the temperature sensor installed in the main circulation loop and the target value is collected in real time to dynamically correct the control signal, so that the medium temperature rises continuously according to the preset heating slope and reaches the target temperature.

7. The control method according to claim 1, characterized in that, The method of continuously adjusting the medium temperature according to a preset cooling slope using a thermal regulation device installed in the main circulation loop via feedback control includes: Pre-start the cascade oil chiller and cool its internal medium to the set temperature; The PLC controller adjusts the opening of the proportional valve according to the set cooling slope to control the heat exchange efficiency between the main circulation loop and the oil chiller. The proportional valve opening is dynamically adjusted based on the deviation between the actual cooling rate and the preset rate, so that the actual cooling rate approaches the preset rate, and the medium temperature continuously decreases according to the preset cooling slope until the target temperature is reached. The actual cooling rate is the calculation result of the PLC based on the real-time temperature sensor feedback value.

8. The control method according to claim 7, characterized in that, It also includes the steps for switching the chiller operating mode: During the linear cooling process, when the actual cooling rate is lower than the preset rate, the cascade oil chiller unit will switch from the cold storage mode to the direct cooling mode.

9. The control method according to claim 1, characterized in that, It also includes mode switching steps: After rapid heating is completed, the switching device is controlled by the PLC controller to return to the off state, so that the energy storage circuit is re-isolated from the main circulation circuit, and the device is switched to linear temperature change mode or heat preservation mode according to the test requirements.

10. A control system for rapid temperature changes at high and low temperatures, used for rapid switching of the medium temperature or linear slope control of a test sample, characterized in that, include: The main circulation loop, which is connected to the test specimen, is used to provide the test specimen with a circulating test medium; The energy storage circuit is connected to the main circulation circuit via a switching device, and is used to independently store and heat the test medium to a preset high temperature, while remaining isolated from the main circulation circuit. A thermal regulation device, disposed in the main circulation loop, is used to heat or cool the test medium in the main circulation loop; and, The controller is connected to the switching device and the thermal regulation device respectively. The controller is used to: control the switching device to instantaneously connect the energy storage circuit and the main circulation circuit when performing rapid heating, so that the high temperature medium in the energy storage circuit is introduced into the main circulation circuit, so that the medium temperature at the inlet of the test sample rises in a step; or control the thermal regulation device to continuously adjust the medium temperature according to the preset temperature change slope in a feedback control mode when performing linear heating or linear cooling, until the target temperature is reached.

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