A liquid cooling energy-saving intelligent control method and system based on PID and PWM double-layer regulation

Abstract

This invention relates to the field of liquid cooling heat dissipation control technology, specifically a liquid cooling energy-saving intelligent control method and system based on dual-layer regulation of PID and PWM. The system hardware is divided into two interactive and independent control loops: a cooling-side power generation source and a liquid cooling-side application source. Based on the PI algorithm, the compressor regulates the total cooling capacity of the system. In the initial stage, the water pump operates at full load to quickly reach the desired temperature. In the steady-state stage, the water pump flow rate is adjusted based on the PWM duty cycle to achieve high-precision control of the outlet water temperature. A correlation between flow rate and PWM duty cycle is established through a fitting formula, achieving coordinated regulation of cooling capacity and flow rate. This invention, based on dual-layer regulation of PID and PWM, effectively improves the temperature control accuracy of the liquid cooling system, reduces the compressor start-up and shutdown frequency, reduces the system's total energy consumption throughout its lifecycle, reduces temperature control fluctuations, and improves the unit's operational reliability and compatibility across various scenarios. It is suitable for various high-power liquid cooling heat dissipation scenarios.

Description

Technical Field

[0001] This invention relates to the field of liquid cooling heat dissipation control technology, specifically a liquid cooling energy-saving intelligent control method and system based on dual-layer regulation of PID and PWM. Background Technology

[0002] With the continuous increase in demand for high-power heat dissipation in scenarios such as high-density computing power and energy storage, the core development trend of liquid cooling unit control technology is evolving from the traditional "passive response" mode to the "active prediction + dynamic coordination" mode, in order to adapt to the industry's industrialization needs for efficient heat dissipation, energy-saving operation and high-precision temperature control.

[0003] Currently, the basic control modes of traditional liquid chiller units used in the industry mainly include constant speed control, single PID regulation, threshold control, and follower control. Among them, in constant speed control mode, the compressor, water pump, and fan all operate at a fixed speed. The control logic is simple, but it suffers from low energy efficiency and frequent start-stop and unloading of the unit. The single PID regulation mode adjusts only based on the temperature difference between the supply and return liquids, which has the defects of slow response speed, large temperature fluctuations when the load changes suddenly, and limited steady-state control accuracy. The threshold control mode triggers the start-stop and regulation of the unit by setting a fixed temperature threshold, which cannot adapt to dynamically changing load conditions and the control process has obvious lag. In the follower control mode, the liquid chiller unit only moves synchronously with the start-stop of the target equipment, which has the problem of start-up delay and is prone to overheating of the target equipment.

[0004] Although existing new liquid cooling control methods have improved response speed and energy saving, they still have unavoidable technical defects. On the one hand, the dynamic temperature control accuracy is insufficient. Traditional control methods are difficult to adapt to high heat loads and millisecond-level load change conditions. During operation, the temperature fluctuation range can reach ±2℃ to ±5℃, which cannot meet the requirements of high-precision temperature control. On the other hand, there is a core contradiction between energy efficiency and reliability. Under the existing control mode, excessive pursuit of temperature control accuracy will directly lead to an increase in system energy consumption. Frequent adjustments to achieve accurate control will significantly affect the service life of the unit's core components. It is impossible to balance temperature control accuracy, energy saving effect and operational reliability. Therefore, in view of the above situation, there is an urgent need to develop a liquid cooling energy-saving intelligent control method and system based on PID and PWM dual-layer regulation to overcome the shortcomings in current practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a liquid cooling energy-saving intelligent control method and system based on dual-layer regulation of PID and PWM, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A liquid cooling energy-saving intelligent control method based on dual-layer regulation of PID and PWM includes the following steps: Step S1: Divide the liquid cooling system into two interactive and independent control loops, namely the cooling energy generation source on the refrigeration side and the cooling energy application source on the liquid cooling side. The cooling energy generation source is used to generate and regulate the total cooling capacity of the system, and the cooling energy application source is used to deliver liquid cooling medium to dissipate heat from the heat source load and to control the temperature of the liquid inlet of the heat source load. Step S2: Based on the PI algorithm, adjust the total cooling capacity of the system through the compressor of the cooling source; During the initial cooling phase of the system, the water pump of the cold energy application source is controlled to run at full load until the temperature at the inlet of the heat source load reaches the tolerance range of the target temperature. Step S3: When the system enters the steady-state fine control stage, the flow rate of the water pump is adjusted based on the PWM duty cycle to achieve high-precision control of the inlet temperature of the heat source load. By establishing a pre-defined fitting relationship between the water pump flow rate and the PWM duty cycle, the coordinated regulation of cooling capacity and flow rate can be achieved.

[0007] As a further aspect of the present invention: In step S2, the total cooling capacity of the system is adjusted by the compressor based on the PI algorithm, specifically as follows: The temperature difference between the measured temperature at the liquid inlet of the heat source load and the target temperature is used as the core driving factor. The compressor speed is controlled based on the PI algorithm so that the compressor output can match the cooling capacity demand of the load.

[0008] As a further aspect of the present invention: In step S2, the water pump operates at full load during the initial cooling phase of the system, specifically as follows: Set the PWM duty cycle of the water pump to 100% to make the liquid cooling side flow reach the upper limit of the system flow until the temperature at the inlet of the heat source load drops to within the tolerance range of the target temperature.

[0009] As a further aspect of the present invention: In step S3, the flow rate of the water pump is adjusted based on the PWM duty cycle during the steady-state fine control stage, specifically as follows: When the temperature at the inlet of the heat source load is within the tolerance range of the target temperature, the PWM duty cycle of the water pump is synchronously adjusted according to the fluctuation trend of the temperature at the inlet of the heat source load to change the flow rate on the liquid cooling side. The flow rate adjustment buffers the temperature fluctuation and converges the control deviation on the cooling side. Among them, the temperature difference fluctuation between the measured temperature at the inlet of the heat source load and the target temperature is the core driving factor for the PWM duty cycle adjustment of the water pump.

[0010] As a further aspect of the present invention: the coordinated adjustment of cooling capacity and flow rate specifically includes: Using the liquid cooling side flow rate regulation result as feedback, the total cooling capacity output of the refrigeration side is synchronously matched to form a dual-layer closed-loop collaborative control of PI regulation and PWM regulation, avoiding frequent compressor start-stop and temperature control overshoot.

[0011] A liquid-cooled energy-saving intelligent control system based on dual-layer regulation of PID and PWM includes a refrigeration cycle unit, a liquid-cooled cycle unit, a sensor unit, and a control unit; The refrigeration cycle unit is a source of cooling capacity, including a compressor, a condenser assembly, an electronic expansion valve, and the refrigerant side of a refrigerant-water heat exchanger. The discharge port of the compressor is connected to the refrigerant inlet of the condenser assembly, the refrigerant outlet of the condenser assembly is connected to the inlet of the electronic expansion valve, the outlet of the electronic expansion valve is connected to the refrigerant side inlet of the refrigerant-water heat exchanger, and the refrigerant side outlet of the refrigerant-water heat exchanger is connected to the suction port of the compressor, forming a closed-loop refrigerant circulation circuit. The liquid cooling circulation unit is a source of cooling capacity, including a water pump, a heat source load, and a liquid-cooled side of a liquid-cooled heat exchanger. The outlet of the liquid-cooled side of the liquid-cooled heat exchanger is connected to the inlet of the heat source load, the outlet of the heat source load is connected to the inlet of the water pump, and the inlet of the liquid-cooled side of the liquid-cooled heat exchanger is connected to the outlet of the water pump, forming a closed-loop liquid cooling medium circulation circuit. The refrigeration cycle unit and the liquid cooling cycle unit have opposite circulation directions at the agent-water heat exchanger to enhance heat exchange efficiency; The sensor unit includes at least an inlet water temperature sensor and an outlet water temperature sensor respectively installed at the inlet of the heat source load and at the outlet of the heat source load, for real-time acquisition of inlet and outlet water temperature data of the liquid cooling medium in the liquid cooling circulation loop. The control unit is electrically connected to the cooling fan, electronic expansion valve, water pump, and sensor unit of the compressor and condenser assembly, respectively. The control unit is configured to execute the liquid cooling energy-saving intelligent control method based on PID and PWM dual-layer regulation described above.

[0012] As a further aspect of the present invention: when the control unit adjusts the operating state of the compressor based on the PI algorithm, it is specifically configured as follows: The core driving factor is the temperature difference between the measured temperature at the heat source load inlet and the target temperature collected by the sensor unit. Based on the PI algorithm, the compressor speed is controlled so that the compressor output matches the cooling capacity required by the load.

[0013] As a further aspect of the present invention: the control unit, during the initial cooling phase of the system, controls the water pump to operate at full load, specifically configured as follows: Set the PWM duty cycle of the water pump to 100% to make the flow rate of the liquid cooling circulation loop reach the upper limit of the system flow rate until the temperature of the heat source load inlet drops to within the tolerance range of the target temperature.

[0014] As a further aspect of the present invention: when the control unit adjusts the water pump flow rate based on the PWM duty cycle during the steady-state fine control phase, it is specifically configured as follows: When the temperature at the inlet of the heat source load is within the tolerance range of the target temperature, the PWM duty cycle of the water pump is synchronously adjusted according to the fluctuation trend of the temperature at the inlet of the heat source load to change the flow rate of the liquid cooling loop. The flow rate adjustment buffers temperature fluctuations and converges the control deviation of the refrigeration cycle unit. Among them, the temperature difference fluctuation between the measured temperature at the inlet of the heat source load and the target temperature is the core driving factor for the PWM duty cycle adjustment of the water pump.

[0015] As a further aspect of the present invention: the control unit is further configured to: Using the liquid cooling side flow rate regulation result as feedback, the total cooling capacity output of the cooling side is synchronously matched to achieve dual-layer closed-loop collaborative control of PI regulation and PWM regulation, thereby reducing system energy consumption and improving temperature control stability.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Low implementation cost: Conventional systems require high-precision compressors, high-end control chips and other hardware to achieve high-precision temperature control and regulation. However, the method and system of this invention reduce the frequency of compressor adjustment and reliance on high-precision control. Conventional control chips can meet the control requirements. At the same time, there is no need to add components to the original system. Implementation and application can be completed only through software updates, hardware and system matching. 2. The iteration and implementation process is simple. To achieve the required adjustment accuracy, existing liquid-cooled units require extensive debugging, calibration, and system matching of the compressor and electronic expansion valve for various operating conditions. The compressor itself has high precision and complex control logic, which makes the iteration and implementation process complicated and lengthy. Although the method and system of this invention increases the debugging and fitting process of the liquid-cooled water pump, it greatly reduces the debugging and adjustment difficulty of the compressor side, and simplifies the overall system implementation process and operation difficulty.

[0017] 3. High control precision: Compared with the existing system, which only controls the output of cooling capacity on the cooling side and converts the energy into liquid cooling medium through the heat exchange process to offset the heat generated by the load, the method and system of this invention divide the cooling-side generation source and the liquid cooling-side application source into two interactive and independent loops, shortening the cooling capacity loop and reducing the amplification effect of the control signal in the process from the generation source to the heat source load. Through the dual-layer adjustment of coarse adjustment of total cooling capacity on the cooling side and fine adjustment of temperature control precision on the liquid cooling side, higher temperature control precision is achieved. 4. The compressor and system start-up and shutdown are more rational, effectively avoiding frequent start-ups and shutdowns. Existing systems, in order to balance precision control and energy saving, adopt a control method that stops the compressor after reaching the target temperature. Affected by factors such as ambient temperature, altitude, load fluctuations, and temperature detection accuracy, the system is prone to overshoot, leading to frequent compressor start-ups and shutdowns. This not only reduces the compressor's lifespan and increases the probability of failure, but even if the frequent start-ups and shutdowns are offset by limiting the compressor's stable operating time, the system's energy consumption will still increase. The method and system of this invention can buffer temperature fluctuations through flow regulation of the liquid-cooled application source, i.e., PWM regulation of the water pump. While achieving regulation precision, it can optimize the compressor's stable operating time without increasing the number of compressor start-ups and shutdowns, and at the same time, it does not increase or even reduces the frequency of water pump start-ups and shutdowns. 5. Reduced energy consumption and greater energy efficiency: By adopting the method and system of this invention, the number of compressor start-stop cycles is reduced and the forced stable operation time of the compressor is optimized. At the same time, the full-load operation time of the water pump is reduced. Within a unit operating cycle, the cooling capacity utilization rate is improved and the total operating power of the system is reduced, thereby achieving the reduction and optimization of system energy consumption. 6. The method and system of this invention achieve temperature regulation through dual circulation and dual-layer control. The flow regulation on the liquid cooling side can buffer, absorb and converge the fluctuations and tolerances on the cooling side, so that the temperature control of the liquid cooling medium finally output to the load has smaller fluctuations and more stable regulation, which can effectively avoid sudden rises and falls in temperature.

[0018] 7. With good control tracking and fast response speed, and no control delay or drift, the dual-cycle dual-layer control of this invention can effectively avoid control overshoot compared with conventional control methods and systems. The heat exchange between the cooling side and the liquid cooling side, and between the liquid cooling side and the load side is more sufficient, the heat exchange temperature difference is smaller, and the temperature regulation tracking, uniformity and consistency are higher, with a significant advantage in temperature regulation speed.

[0019] 8. Strong applicability: The technical solution of this invention has good adaptability to large and small liquid cooling units, different refrigerant types, different water pump specifications and different system control strategies. Through fitting and calibration, the best matching parameter values ​​can be found to achieve the control objectives of this invention.

[0020] 9. Good compatibility with product systems in different application scenarios. This solution is compatible with vehicle liquid cooling systems to achieve thermal management of vehicle equipment. It is also compatible with energy storage liquid cooling systems, data centers and even robot liquid cooling systems. Only the optimal parameter values ​​need to be fitted and calibrated according to the system characteristics of different application scenarios. 10. The method and system of the present invention can reduce or avoid system failures. They reduce the reliance on and over-adjustment of highly complex and high-value core components, reduce the complexity of the operating conditions of core components and the proportion of operating limit conditions, thereby improving the durability of core components and the duration of optimal operating conditions, and reducing or avoiding the probability of system failures and component failures. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a liquid-cooled energy-saving intelligent control system based on dual-layer regulation of PID and PWM in an embodiment of the present invention.

[0022] In the diagram: 1-Compressor, 2-Condenser assembly, 3-Electronic expansion valve, 4-Refrigerant water heat exchanger, 5-Water pump, 6-Heat source load. Detailed Implementation

[0023] 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.

[0024] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0025] Please see Figure 1 This invention provides a liquid cooling energy-saving intelligent control system based on dual-layer regulation of PID and PWM, and a liquid cooling energy-saving intelligent control method based on this system, which solves the problems of insufficient temperature control accuracy, high energy consumption and poor component durability caused by frequent adjustment in existing liquid cooling systems, and achieves high-precision temperature control, reduced adjustment frequency, energy saving and consumption reduction and improved system operation reliability.

[0026] I. System Overall Architecture The liquid-cooled energy-saving intelligent control system of this embodiment includes a refrigeration unit, a heat dissipation unit, a flow regulation unit, a heat exchange unit, a liquid cooling circulation unit, a sensor unit, and a control unit, as detailed below: The refrigeration unit, with compressor 1 as its core component, is used to realize the compression cycle of refrigerant, generate low-temperature cooling capacity and output it. It is the core component for generating the cooling capacity of the system. The heat dissipation unit, with the condenser assembly 2 as its core component, is used to dissipate excess heat generated by the refrigerant during the refrigeration cycle and to achieve the condensation and liquefaction of the refrigerant. The flow regulation unit, with its core component being the electronic expansion valve 3, is used to dynamically regulate the flow rate of refrigerant in the refrigeration cycle, thereby achieving dynamic and precise matching of refrigerant flow and adjustment of cooling capacity. The heat exchange unit, with its core component being the refrigerant-water heat exchanger 4, is used to realize the heat exchange between the refrigerant and the liquid cooling medium, and to complete the transfer of cooling capacity from the refrigeration side to the liquid cooling side. The core components of the liquid cooling circulation unit are the water pump 5 and its matching pipeline, which are used to drive the liquid cooling medium to circulate and deliver low-temperature liquid cooling medium to the heat source load 6, thereby removing the heat generated by the heat source load 6. Heat source load 6 is the heat dissipation target of the system and is the heat absorption end of the liquid cooling medium; The sensor unit includes at least an inlet water temperature sensor installed at the liquid inlet of the heat source load 6 and an outlet water temperature sensor installed at the liquid outlet of the heat source load 6, for real-time acquisition of inlet and outlet liquid temperature data of the liquid cooling medium in the liquid cooling circulation loop. The control unit, which is the TMS control hardware and software system, consists of integrated circuits and control chips. It is used to receive temperature data collected by sensor units and operating status data of various components. Based on the preset control model, PID algorithm and control logic, it outputs control signals to drive the start and stop of various components and adjust their operating status.

[0027] In this embodiment, the exhaust port of compressor 1 is connected to the refrigerant inlet of condenser assembly 2, the refrigerant outlet of condenser assembly 2 is connected to the inlet of electronic expansion valve 3, the outlet of electronic expansion valve 3 is connected to the refrigerant-side inlet of refrigerant-water heat exchanger 4, and the refrigerant-side outlet of refrigerant-water heat exchanger 4 is connected to the suction port of compressor 1, forming a closed-loop refrigerant circulation circuit, i.e., the source of refrigerant generation. The liquid-cooled side outlet of the agent-water heat exchanger 4 is connected to the liquid inlet of the heat source load 6, the liquid outlet of the heat source load 6 is connected to the inlet of the water pump 5, and the liquid-cooled side inlet of the agent-water heat exchanger 4 is connected to the outlet of the water pump 5, forming a closed-loop liquid-cooled medium circulation loop, i.e., the application source. The generation source and the application source have opposite circulation directions at the heat exchanger to enhance heat exchange efficiency; The TMS control hardware and software system are electrically connected to the cooling fan of compressor 1, condenser assembly 2, electronic expansion valve 3, water pump 5, and temperature sensors of the sensor unit, respectively, to realize data acquisition and operation control.

[0028] II. Liquid Cooling Energy-Saving Intelligent Control Method Based on PID Algorithm and PWM Control Based on the above system, the liquid cooling energy-saving intelligent control method of this embodiment specifically includes the following steps, and adopts a control logic that integrates the solution and the effect throughout the process: Step 1: System Hardware Logic Partitioning The TMS control hardware and software system divides the system hardware into two interactive and independent control loops: a cooling capacity generation source and a cooling capacity application source. The generation source is the refrigerant-side loop, consisting of compressor 1, condenser assembly 2, and electronic expansion valve 3. Its core function is to respond to the system's temperature requirements and generate and regulate the system's total cooling capacity. The application source is the liquid-cooled-side loop, consisting of refrigerant-water heat exchanger 4, water pump 5, and heat source load 6. Its core function is to respond to the system's flow requirements and achieve high-precision control of the outlet water temperature. All components are uniformly controlled by the TMS control hardware and software system based on preset control logic.

[0029] This step shortens the cooling capacity circulation path by separating the cooling-side power generation source and the liquid-cooling-side application source into two interactive yet independent cycles. It also reduces the amplification effect of the control signal in the process from the power generation source to the heat source load, laying the foundation for higher control precision in subsequent dual-layer regulation. At the same time, it reduces the coupling of system control and simplifies the debugging difficulty of single-cycle operation.

[0030] Step 2: Source cooling capacity control based on PI algorithm The compressor 1 operates in response to the temperature demand of the system and controls the generation of the total cooling capacity of the system. The TMS control hardware and software system uses the temperature difference ΔT between the liquid inlet on the heat source load 6 side and the target temperature as the core driving trigger factor, and controls the speed of compressor 1 based on the PI algorithm so that the compressor 1 outputs a cooling capacity that matches the load demand.

[0031] In this step, based on the law of conservation of energy, the relationship between cooling capacity and temperature and flow rate is as follows: Q=m×c×ΔT=(ρ×V)×c×ΔT; Where m is the volumetric mass of the liquid, ρ is the density of the liquid-cooled medium × V is the volumetric flow rate of the liquid, and the unit is m³ / s. 3 / s; c is the isobaric specific heat capacity of the liquid-side medium, a physical constant; ΔT is the temperature difference between the outlet of this device (i.e., the inlet of the load) and the target temperature, in °C. ΔT=T 出口 -T 目标 .

[0032] In the initial stage of the system, i.e., the cooling and temperature reduction stage from demand triggering to the outlet water temperature reaching the target tolerance range, the TMS control hardware and software system controls the liquid flow rate V on the liquid cooling side to the upper limit of the system flow rate, and the PWM duty cycle of water pump 5 is set to 100% until the outlet water temperature reaches the target tolerance range. For example, when the system's temperature control accuracy is set to ±2℃ and the target temperature is 20℃, when the outlet water temperature drops to 22℃, it is determined that the target tolerance range has been reached.

[0033] This step uses a PI algorithm to control the speed of compressor 1 based on the temperature difference between the inlet and outlet liquids, thus achieving a coarse adjustment of the total cooling capacity of the system. This enables a rapid response to the system's high-load cooling demand and shortens the time to reach the target temperature during the cooling phase. At the same time, in the initial stage, the PWM duty cycle of water pump 5 is maximized to 100%, thereby maximizing the flow rate of the liquid cooling medium and further improving the cooling rate, quickly reducing the outlet water temperature to within the target tolerance range.

[0034] Step 3: Precise Temperature Control Based on PWM Control The operation status of water pump 5 is based on the flow demand of the core response system and the control accuracy of the outlet water temperature, especially the high-precision temperature control within a small temperature difference range. The TMS control hardware and software system adjusts the PWM duty cycle of water pump 5 to change the liquid flow rate V on the liquid cooling side, thereby achieving high-precision temperature control within a small temperature range. At the same time, it buffers the rate of temperature change to avoid overshoot and prevents frequent start-stop of compressor 1, thus reducing the stabilization time required to avoid overshoot of compressor 1.

[0035] The control process for this step is divided into two stages, as detailed below: The first stage is the initial cooling stage, which has been described in detail in step 2 and will not be repeated here; The second stage is the steady-state precision control stage, which is the stage where the outlet water temperature fluctuates within the target temperature tolerance range. For example, when the target temperature is 20℃ and the temperature control accuracy is ±2℃, the outlet water temperature changes within the range of 18℃ to 22℃.

[0036] Once the outlet water temperature reaches the target temperature tolerance, the TMS control hardware and software system controls the PWM duty cycle of water pump 5 to decrease synchronously from 100% as the temperature decreases, with the rate of decrease gradually slowing down, and reaching a minimum of about 95%. When the outlet water temperature is lower than the absolute value of the target temperature and shows a downward deviation trend, the PWM duty cycle of water pump 5 is synchronously increased to 100%, with the rate of increase gradually increasing. During this process, the fluctuation of the inlet and outlet liquid temperature difference ΔT is the core driving trigger factor for the adjustment of the PWM duty cycle of water pump 5.

[0037] The control logic for this step is derived based on the following core formula: 1. Energy conservation formula: In the steady-state fine control stage, the cooling capacity Q output by compressor 1 is a stable value. Therefore, the flow rate V on the liquid cooling side is inversely proportional to the temperature difference ΔT between the inlet and outlet liquids. That is, by adjusting the flow rate V, the ΔT can be finely adjusted, thereby achieving high-precision control of the outlet water temperature. 2. The formula relating pump head and flow rate, based on Bernoulli's equation and the law of conservation of energy: H = S × V 2 ; Where H is the required head or total resistance loss of the system, in meters or kPa; V is the liquid-side volumetric flow rate, in cubic meters per second (m³).3 / h; S is the pipe resistance coefficient, a constant related to the characteristics of the pipe itself; when the flow rate V doubles, the system flow resistance H will increase to four times the original value, and conversely, when the flow rate is halved, the flow resistance will decrease to one-quarter of the original value.

[0038] 3. Pump power consumption formula: The shaft power of a water pump is directly proportional to the product of its flow rate and head, i.e., P∝V×H, combined with H∝V 2 It can be deduced that P∝V 3 This means that a small increase in pump flow rate will lead to a cubic increase in power, and conversely, a small decrease in flow rate can result in a significant reduction in pump power consumption, providing a theoretical basis for system energy saving.

[0039] Considering the non-ideal state of the actual system, this embodiment uses a high-precision fitting formula to establish the correlation between the flow rate V and the PWM duty cycle, as follows: V = a × (PWM) 2 +b×(PWM)+c; Where V is the liquid-side volumetric flow rate, in m³ / s. 3 / h; PWM is the PWM duty cycle, limited from 0 to 100%; a, b, and c are coefficients obtained by fitting experimental data.

[0040] Based on the above fitting formula, the PWM duty cycle corresponding to the target flow rate can be derived, and the calculation formula is as follows: Among them, V set The target flow rate.

[0041] The TMS control hardware and software system calculates the discriminant Δ=b of the above formula. 2 -4a(cV), if Δ<0, it means that the target flow rate V exceeds the maximum output capacity or minimum stable operating capacity of the water pump 5. At this time, directly output PWM=100 (maximum flow rate) or PWM=0 (minimum flow rate).

[0042] Furthermore, for products and systems of different specifications, the optimal rate of change of the matching PWM duty cycle adjustment can be found through testing, calibration and parameter training, so that the temperature difference ΔT based on the PI algorithm and the work of the compressor 1 and the PWM control drive of the water pump 5 can form a coordinated control to achieve the control objective of this embodiment.

[0043] This step achieves fine-tuning of flow rate by adjusting the PWM duty cycle of water pump 5, thereby achieving high-precision temperature control. Compared with the existing scheme that only adjusts through compressor 1, it can improve the temperature control accuracy by about 30%, reduce the start-stop and adjustment frequency of compressor 1 by about 20%, and shorten the stabilization time of compressor 1 after reaching the temperature by about 30%. It significantly improves the temperature control accuracy while reducing the frequent adjustment losses of compressor 1. Meanwhile, based on the cubic relationship between water pump power consumption and flow rate, reducing the full-load operation time of water pump 5 can significantly reduce water pump power consumption, improve system cooling capacity utilization, and achieve significant energy-saving effects. In addition, by regulating the flow rate on the liquid cooling side to buffer temperature fluctuations, control fluctuations on the refrigeration side can be effectively absorbed, avoiding sudden temperature rises and falls, resulting in smaller control fluctuations in the system output temperature and more stable operation. At the same time, it avoids frequent start-stop of compressor 1 and improves the service life of core components.

[0044] It should be noted that, in this invention, although the specification describes the embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. 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 liquid cooling energy-saving intelligent control method based on PID and PWM double-layer regulation, characterized in that, Includes the following steps: Step S1: Divide the liquid cooling system into two interactive and independent control loops, namely the cooling energy generation source on the refrigeration side and the cooling energy application source on the liquid cooling side. The cooling energy generation source is used to generate and regulate the total cooling capacity of the system, and the cooling energy application source is used to deliver liquid cooling medium to dissipate heat from the heat source load and to control the temperature of the liquid inlet of the heat source load. Step S2: Based on the PI algorithm, adjust the total cooling capacity of the system through the compressor of the cooling source; During the initial cooling phase of the system, the water pump of the cold energy application source is controlled to run at full load until the temperature at the inlet of the heat source load reaches the tolerance range of the target temperature. Step S3: When the system enters the steady-state fine control stage, the flow rate of the water pump is adjusted based on the PWM duty cycle to achieve high-precision control of the inlet temperature of the heat source load. By establishing a pre-defined fitting relationship between the water pump flow rate and the PWM duty cycle, the coordinated regulation of cooling capacity and flow rate can be achieved.

2. The liquid cooling energy-saving intelligent control method based on PID and PWM double-layer regulation according to claim 1, characterized in that, In step S2, the total cooling capacity of the system is adjusted by the compressor based on the PI algorithm, specifically as follows: Using the temperature difference between the measured temperature at the liquid inlet on the load side of the heat source and the target temperature as the core driving factor, the compressor speed is controlled based on the PI algorithm so that the compressor output can match the cooling capacity demand of the load.

3. The liquid cooling energy-saving intelligent control method based on PID and PWM double-layer regulation according to claim 1, characterized in that, In step S2, the water pump operates at full load during the initial cooling phase of the system, specifically: Set the PWM duty cycle of the water pump to 100% to make the liquid cooling side flow reach the upper limit of the system flow until the temperature at the inlet of the heat source load drops to within the tolerance range of the target temperature.

4. The liquid cooling energy-saving intelligent control method based on PID and PWM double-layer regulation according to claim 1, characterized in that, In step S3, the steady-state fine control stage adjusts the water pump flow rate based on the PWM duty cycle, specifically as follows: When the temperature at the inlet of the heat source load is within the tolerance range of the target temperature, the PWM duty cycle of the water pump is synchronously adjusted according to the fluctuation trend of the temperature at the inlet of the heat source load to change the flow rate on the liquid cooling side. The flow rate adjustment buffers the temperature fluctuation and converges the control deviation on the cooling side. Among them, the temperature difference fluctuation between the measured temperature at the inlet of the heat source load and the target temperature is the core driving factor for the PWM duty cycle adjustment of the water pump.

5. The liquid cooling energy-saving intelligent control method based on PID and PWM double-layer regulation according to claim 1, characterized in that, The coordinated adjustment of cooling capacity and flow rate specifically includes: Using the liquid cooling side flow rate regulation result as feedback, the total cooling capacity output of the refrigeration side is synchronously matched to form a dual-layer closed-loop collaborative control of PI regulation and PWM regulation, avoiding frequent compressor start-stop and temperature control overshoot.

6. A liquid cooling energy-saving intelligent control system based on PID and PWM double-layer regulation, characterized in that, It includes a refrigeration cycle unit, a liquid cooling cycle unit, a sensor unit, and a control unit; The refrigeration cycle unit is a source of cooling capacity, including a compressor, a condenser assembly, an electronic expansion valve, and the refrigerant side of a refrigerant-water heat exchanger. The discharge port of the compressor is connected to the refrigerant inlet of the condenser assembly, the refrigerant outlet of the condenser assembly is connected to the inlet of the electronic expansion valve, the outlet of the electronic expansion valve is connected to the refrigerant side inlet of the refrigerant-water heat exchanger, and the refrigerant side outlet of the refrigerant-water heat exchanger is connected to the suction port of the compressor, forming a closed-loop refrigerant circulation circuit. The liquid cooling circulation unit is a source of cooling capacity, including a water pump, a heat source load, and a liquid-cooled side of a liquid-cooled heat exchanger. The outlet of the liquid-cooled side of the liquid-cooled heat exchanger is connected to the inlet of the heat source load, the outlet of the heat source load is connected to the inlet of the water pump, and the inlet of the liquid-cooled side of the liquid-cooled heat exchanger is connected to the outlet of the water pump, forming a closed-loop liquid cooling medium circulation circuit. The refrigeration cycle unit and the liquid cooling cycle unit have opposite circulation directions at the agent-water heat exchanger to enhance heat exchange efficiency; The sensor unit includes at least an inlet water temperature sensor and an outlet water temperature sensor respectively installed at the inlet of the heat source load and at the outlet of the heat source load, for real-time acquisition of inlet and outlet water temperature data of the liquid cooling medium in the liquid cooling circulation loop. The control unit is electrically connected to the cooling fan, electronic expansion valve, water pump, and sensor unit of the compressor and condenser assembly, respectively. The control unit is configured to execute the liquid cooling energy-saving intelligent control method based on PID and PWM dual-layer regulation as described in any one of claims 1-5.

7. The liquid cooling energy-saving intelligent control system based on PID and PWM double-layer regulation according to claim 6, characterized in that, When the control unit adjusts the compressor's operating state based on the PI algorithm, it is specifically configured as follows: The core driving factor is the temperature difference between the measured temperature at the heat source load inlet and the target temperature collected by the sensor unit. Based on the PI algorithm, the compressor speed is controlled so that the compressor output matches the cooling capacity required by the load.

8. The liquid cooling energy-saving intelligent control system based on PID and PWM double-layer regulation according to claim 6, characterized in that, The control unit is specifically configured to operate the water pump at full load during the initial cooling phase of the system as follows: Set the PWM duty cycle of the water pump to 100% to make the flow rate of the liquid cooling circulation loop reach the upper limit of the system flow rate until the temperature of the heat source load inlet drops to within the tolerance range of the target temperature.

9. The liquid cooling energy-saving intelligent control system based on PID and PWM double-layer regulation according to claim 6, characterized in that, When the control unit adjusts the water pump flow rate based on the PWM duty cycle during the steady-state fine control phase, it is specifically configured as follows: When the temperature at the inlet of the heat source load is within the tolerance range of the target temperature, the PWM duty cycle of the water pump is synchronously adjusted according to the fluctuation trend of the temperature at the inlet of the heat source load to change the flow rate of the liquid cooling loop. The flow rate adjustment buffers the temperature fluctuation and converges the control deviation of the refrigeration cycle unit. Among them, the temperature difference fluctuation between the measured temperature at the inlet of the heat source load and the target temperature is the core driving factor for the PWM duty cycle adjustment of the water pump.

10. The liquid cooling energy-saving intelligent control system based on PID and PWM double-layer regulation according to claim 6, characterized in that, The control unit is also configured to: Using the liquid cooling side flow rate regulation result as feedback, the total cooling capacity output of the cooling side is synchronously matched to achieve dual-layer closed-loop collaborative control of PI regulation and PWM regulation, thereby reducing system energy consumption and improving temperature control stability.

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