Data center liquid cooling manifold self-flow control method

Abstract

This application relates to the field of liquid cooling control technology and discloses a self-flow equalization control method for data center liquid cooling manifolds, including: collecting baseline operating data at steady state time to establish a manifold hydraulic fingerprint; determining whether a branch topology change event has occurred, identifying the target branch as a new branch, a removed branch, or an expanded branch, and applying a change rate constraint to the controllable actuators; performing trial liquid supply for new branches and calculating the disturbance coefficient and hydraulic identification reliability coefficient; generating a progressive target flow sequence for new and expanded branches and adjusting the controllable actuators; determining whether to enter a slow-release mode for removed branches and redistributing the target flow to the remaining branches; and updating the manifold hydraulic fingerprint after the branch topology change event ends. By identifying and processing branch topology change events, this application can reduce the risks of sudden drops in cooling flow to existing servers, sudden changes in manifold differential pressure, and flow oscillations during branch switching.

Description

Technical Field

[0001] This application relates to the field of liquid cooling control technology, and more specifically, to a self-flow equalization control method for liquid cooling manifolds in data centers. Background Technology

[0002] With the development of artificial intelligence training, high-performance computing, and cloud computing, the power density of single server racks in data centers continues to increase, and traditional air cooling methods can no longer meet the heat dissipation requirements of servers with high heat flux density. Liquid cooling technology, due to its high heat exchange efficiency and stable temperature control, is gradually being applied to high-density server racks. As a component for distributing and collecting coolant within the rack, the liquid cooling manifold typically connects multiple server nodes through multiple parallel liquid cooling branches, and its flow distribution status directly affects the cooling security of each server node.

[0003] Existing liquid cooling control methods mostly employ strategies such as constant flow rate, constant differential pressure, temperature threshold, pump speed regulation, or valve opening regulation. When the number of server nodes is fixed, the connection status of each branch is stable, and the heat load changes gradually, these methods can maintain the cooling flow rate of the branches to a certain extent. However, in actual data center operations and maintenance, server maintenance, replacement, hot-swapping, online expansion, or failure node shutdown are common occurrences, and branches on the liquid cooling manifold may experience online connection, removal, or sudden load increases.

[0004] When the branch conditions change, the parallel network structure of the liquid cooling manifold, the equivalent hydraulic resistance, and the pressure-flow distribution relationship between the branches will change accordingly. Newly connected branches may have significantly different hydraulic characteristics from existing branches due to differences in cold plate structure, pipe length, quick-connect status, liquid filling status, or internal flow channel resistance. Branch removal or load expansion will also change the original flow distribution balance. If fixed pressure difference, fixed opening degree, or simple temperature threshold control is still used, it may cause some branches to momentarily compete for flow, reduce the flow of existing server branches, or prevent newly added or expanded branches from obtaining the required coolant in time, thereby causing the risk of chip temperature rise, server frequency reduction, or even protection shutdown. At the same time, sudden changes in flow may also cause manifold pressure difference fluctuations, flow oscillations, and local pressure shocks, affecting the system's operational stability and sealing reliability. Summary of the Invention

[0005] This application aims to address the problems of unbalanced flow distribution among liquid cooling branches, drop in cooling flow of existing branches, insufficient liquid supply to changed branches, and pressure fluctuations in manifolds caused by sudden changes in branch topology and hydraulic state during the online connection, removal, or expansion of server branches in data center liquid cooling manifolds, and provides a self-flow equalization control method for data center liquid cooling manifolds.

[0006] This application provides a self-flow sharing control method for liquid-cooled manifolds in data centers, including: At steady state, baseline operating data is collected, hydraulic impedance data is calculated based on the baseline operating data, and a manifold hydraulic fingerprint is established based on the baseline operating data and the hydraulic impedance data. Monitor the discrimination value of each branch, determine whether a branch topology change event has occurred based on the discrimination value, and determine the corresponding target branch as a new branch, a removed branch, or an expanded branch based on the event type of the branch topology change event. Calculate the lower limit of the protection flow based on the manifold hydraulic fingerprint and apply change rate constraints to the controllable actuators. Based on the rate of change constraint, a trial liquid supply is performed on the newly added branch. The hydraulic impedance data of the newly added branch is calculated under the trial liquid supply, and the disturbance coefficient and hydraulic identification confidence coefficient are calculated. For newly added branches, a progressive target flow sequence is generated based on the hydraulic impedance data, disturbance coefficient, and hydraulic identification reliability coefficient of the newly added branches. For expanded branches, a progressive target flow sequence is generated based on the server node power consumption, branch outlet temperature, and branch inlet temperature. The controllable actuator is adjusted based on the progressive target flow sequence and the lower limit of the protection flow. For branch removal, the flow percentage is calculated based on baseline operating data, and the flow percentage is used to determine whether to enter the slow release mode and reallocate the target flow to the remaining branches; the manifold hydraulic fingerprint is updated after the branch topology change event ends.

[0007] Furthermore, methods for establishing manifold hydraulic fingerprints include: When the changes in the connection status of all branches, the valve opening of each branch, the total flow rate of the manifold, and the manifold differential pressure within the preset system stability determination time window do not exceed the corresponding preset steady-state threshold, it is determined to be a steady-state moment, and the current online branch set is recorded as the existing branch set; where the manifold differential pressure is the difference between the supply pressure and the return pressure. Obtain the baseline operating data of each existing branch, and calculate the hydraulic impedance data based on the baseline operating data; The existing branch set, baseline operating data, and hydraulic impedance data are combined to form a manifold hydraulic fingerprint.

[0008] Furthermore, methods for calculating hydraulic impedance data include: The hydraulic impedance data includes combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance; The combined hydraulic impedance is the quotient obtained by dividing the manifold reference pressure difference in the reference operating data by the correction denominator, which is the sum of the square of the branch reference flow rate in the reference operating data and the preset flow rate square correction constant. The hydraulic impedance of the valve section is equal to the quotient obtained by dividing 1 by the denominator, where the denominator is the sum of the square of the product of the branch's preset flow coefficient and the effective flow function value, and the preset square correction constant for the flow capacity; the effective flow function is obtained by segmenting the intervals in which the branch valve opening is located. The hydraulic impedance of the cold plate section is equal to the difference between the combined hydraulic impedance and the valve section hydraulic impedance.

[0009] Furthermore, the method for calculating the lower limit of the protection flow and imposing a rate-of-change constraint on the controllable actuator includes: When the discriminant meets one of the preset explicit judgment conditions or meets the preset implicit judgment conditions, a branch topology change event is determined to have occurred. When a branch topology change event occurs, for each existing branch, the lower limit of the protection flow rate is calculated based on the baseline flow rate and the preset minimum safe cooling flow rate. The rate of change constraints include manifold differential pressure change rate constraints and valve opening change rate constraints. The manifold differential pressure change rate constraint includes that the absolute value of the derivative of the manifold differential pressure with respect to time is not greater than the preset maximum manifold differential pressure change rate. The valve opening change rate constraint includes that the absolute value of the derivative of the branch valve opening with respect to time is not greater than the preset maximum valve opening change rate.

[0010] Furthermore, the methods for determining implicit conditions include: Based on the current total manifold flow, the bypass flow directly measured by the bypass flow sensor, and the baseline total manifold flow and baseline bypass flow in the baseline operating data, calculate the residual total flow of the manifold branch; Calculate the difference between the current manifold differential pressure and the manifold reference differential pressure to obtain the manifold differential pressure residual. For each existing branch, the predicted change in total flow rate of the manifold branch is calculated based on the effective flow function values ​​under the current valve opening and the reference valve opening, the current manifold differential pressure and the reference manifold differential pressure. When the absolute value of the difference between the residual total flow of the manifold branch and the predicted change in the total flow of the manifold branch is greater than the preset threshold for judging the change in the total flow of the manifold, or when the absolute value of the residual differential pressure of the manifold is greater than the preset threshold for judging the change in the differential pressure of the manifold, the implicit judgment condition is determined to be met.

[0011] Furthermore, methods for calculating the hydraulic impedance data of newly added branches include: Based on the server node power consumption, estimate the initial target traffic value of the newly added branch, and determine the trial opening degree based on the preset trial traffic ratio and the initial target traffic value. Under the constraint of valve opening change rate, the valve opening of the newly added branch is increased to the test opening and the preset test time is maintained, and data is collected during the test phase. Based on the data from the trial phase, the combined hydraulic impedance and valve section hydraulic impedance of the newly added branch under the trial opening were calculated respectively. Based on the combined hydraulic impedance and valve section hydraulic impedance under the trial opening, the hydraulic impedance of the cold plate section was calculated.

[0012] Furthermore, methods for calculating the disturbance coefficient and the hydraulic identification confidence coefficient include: Collect the branch traffic flow of newly added branches and existing branches during the trial phase; The maximum value between the difference between the baseline flow of the existing branch and the branch flow during the trial phase and zero is set as the flow drop. The disturbance coefficient of the new branch is calculated based on the flow drop and the branch flow during the trial phase. The hydraulic identification reliability coefficient of the newly added branch is calculated based on the branch flow, initial target flow, trial phase data, and disturbance coefficient during the trial phase.

[0013] Furthermore, for newly added branches, methods for generating progressive target flow sequences include: The target flow rate of the newly added branch is updated based on the server node power consumption, branch outlet temperature and branch inlet temperature, and the final target flow rate is obtained after limiting processing; Based on the hydraulic impedance, disturbance coefficient, and hydraulic identification reliability coefficient of the cold plate section of the newly added branch under the trial opening, the total number of control stages for the corresponding newly added branch is determined. For each control stage, the target flow of the control stage is calculated based on the asymptotic coefficient, the branch flow of the trial stage, and the final target flow. The asymptotic coefficient satisfies a monotonically increasing relationship and the asymptotic coefficient of the last control stage is equal to 1. The progressive target flow sequence includes the total number of control stages for the new branch, the control stage number, the progressive coefficient for each control stage, and the target flow for each control stage.

[0014] Furthermore, for expanding branches, methods for generating progressive target flow sequences include: The target flow rate of the expanded branch is updated based on the server node power consumption, branch outlet temperature and branch inlet temperature, and then the target flow rate of the expanded branch is obtained after limiting processing. Based on the target flow rate of the expanded branch, the current flow rate of the expanded branch, the target valve opening corresponding to the target flow rate of the expanded branch, the current valve opening of the expanded branch, and the preset basic stage number, determine the total number of control stages for the corresponding expanded branch. Based on the current branch flow of the expansion branch, the target flow of the expansion branch, the total number of control stages of the expansion branch, and the asymptotic coefficients corresponding to each control stage, the asymptotic target flow sequence of the expansion branch is determined.

[0015] Furthermore, methods for determining whether to enter the mitigation mode and reallocate the target traffic to the remaining branches include: Subtract the reference bypass flow from the reference manifold total flow, and add the preset branch flow correction constant to obtain the correction denominator; divide the reference flow of the removed branch by the correction denominator to obtain the flow percentage. When the flow rate ratio is greater than the preset threshold for the flow rate ratio of the removed branch, the system enters the slow release mode. In the slow release mode, the bypass valve and variable frequency pump in the controllable actuator are adjusted based on the manifold pressure difference. The set of all branches in the existing branch set, excluding the removed branches, is determined as the remaining branch set. Target traffic is allocated to each branch in the remaining branch set according to power consumption weight, which is the quotient obtained by dividing the power consumption of the server node of the branch by the sum of the power consumption of the server nodes of all branches in the remaining branch set.

[0016] Furthermore, methods for updating manifold hydraulic fingerprints include: After the branch topology change event ends, the steady-state moment is re-determined and the baseline operating data after the event ends is collected; For each branch in the current branch set, the product of the preset historical weight coefficient and the combined hydraulic impedance before the update, plus the product of the remaining weight and the combined hydraulic impedance calculated based on the baseline operating data after the event ends, is used as the updated combined hydraulic impedance. The remaining weight is 1 minus the preset historical weight coefficient. The updated valve section hydraulic impedance and cold plate section hydraulic impedance are calculated based on the updated combined hydraulic impedance and the baseline valve opening after the event ends. Replace the corresponding data in the manifold hydraulic fingerprint with the updated current branch set, the baseline operating data after the event ends, and the hydraulic impedance data.

[0017] The beneficial effects of this application are as follows: By establishing a manifold hydraulic fingerprint at steady state, this application enables the liquid-cooled manifold to have a reference hydraulic state that can be used for subsequent judgment and adjustment before the branch state changes, thus avoiding the need for coarse control based solely on fixed pressure difference, fixed valve opening, or a single temperature threshold.

[0018] This application can identify branch topology change events based on the discriminant of each branch when adding, removing or expanding server branches, and set a protection flow lower limit and execution component change rate constraint for existing branches after the event occurs, thereby reducing the risk of sudden drop in cooling flow, sudden change in manifold pressure difference and flow oscillation of existing servers during branch switching.

[0019] For newly added branches, this application obtains hydraulic impedance data by probing the liquid supply and generates a progressive target flow sequence by combining the disturbance coefficient and hydraulic identification reliability coefficient. This allows the new branch to gradually transition from a low flow state to the target cooling flow, preventing the new branch from affecting the cooling safety of existing branches due to instantaneous flow competition and avoiding the impact of insufficient liquid supply on the online operation of new servers. For expansion branches, this application generates a progressive target flow sequence by combining server node power consumption and branch inlet and outlet liquid temperatures. This ensures that the flow adjustment of the branch after the increase in heat load matches the actual heat dissipation demand, improving the cooling response capability and flow sharing stability during the expansion process. For removed branches, this application calculates the flow ratio based on baseline operating data and determines whether to enter the slow release mode and redistribute the target flow to the remaining branches, which can reduce the flow shock and pressure fluctuation caused by branch removal.

[0020] This application updates the manifold hydraulic fingerprint after the event ends, enabling the control baseline to be adaptively updated according to the actual operating status of the liquid-cooled cabinet, thereby improving the control reliability during subsequent online maintenance, expansion, and node switching. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the self-flow equalization control method for data center liquid-cooled manifolds according to this application. Figure 2 This is an example diagram illustrating the application of a rate-of-change constraint on a controllable actuator; Figure 3 This is a flowchart illustrating the calculation process of the disturbance coefficient and hydraulic identification confidence coefficient in this application. Detailed Implementation

[0022] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0023] A self-flow equalization control method for data center liquid cooling manifolds is applied to data center liquid-cooled cabinets equipped with liquid cooling manifolds. The liquid cooling manifold includes a supply manifold and a return manifold. The supply manifold is connected to the cold plate assemblies of N server nodes through N parallel liquid cooling branches. The return manifold is used to collect the return coolant from each liquid cooling branch. The inlet and outlet of each liquid cooling branch are connected to the cold plate inlet and outlet of the corresponding server node through quick-connect connectors. The quick-connect connector connection method enables the server node to achieve online hot-swapping of a single node without emptying the entire liquid cooling loop, thereby providing a physical interface basis for the online processing of subsequent branch topology change events.

[0024] The liquid-cooled manifold is equipped with controllable actuators. The controllable actuators include branch valves on each liquid-cooled branch for regulating the coolant flow rate of that branch; the controllable actuators also include bypass valves connected between the supply manifold and the return manifold for absorbing short-term flow disturbances when a new branch is added or an existing branch is removed; the controllable actuators also include variable frequency pumps that supply liquid to the liquid-cooled manifold for regulating the manifold supply pressure or the total flow rate of the manifold.

[0025] A detection component is installed on the liquid cooling manifold. This component includes a supply pressure sensor and a total flow sensor on the supply manifold, used to detect the supply pressure and total flow rate of the manifold, respectively. The total flow sensor is positioned on the supply manifold immediately downstream of the variable frequency pump outlet and upstream of the connection point of the bypass line between the supply and return manifolds on the supply manifold side. This ensures that the total flow rate measured by the total flow sensor includes the sum of the bypass flow rate returning through the bypass line and the branch flow rate to each liquid cooling branch. This placement allows the manifold controller to accurately obtain the total supply flow rate to each liquid cooling branch by subtracting the bypass flow rate from the total manifold flow rate, providing a complete flow measurement benchmark for subsequent flow conservation calculations and estimation of flow rates for newly added branches. The detection component also includes a bypass flow sensor located on the aforementioned bypass line for detecting the bypass flow rate. Furthermore, the detection component includes a return pressure sensor on the return manifold for detecting the return pressure. The detection component also includes sensors for each... The liquid cooling branch is equipped with inlet and outlet temperature sensors to detect the inlet and outlet temperatures of the branch, respectively. The detection component also includes a valve opening detection module on each liquid cooling branch to detect the valve opening. Furthermore, the detection component includes a server node connection status detection module on the quick-connect fitting to detect the branch connection status; a connection status value of 1 indicates the branch is connected, while a value of 0 indicates it is not connected. The detection component also includes a branch location identification module on the quick-connect fitting, each pre-storing a unique branch location identification code bound to its corresponding branch number. This code is reported to the manifold controller via the server management interface when a server node is connected or removed. Finally, the detection component includes branch flow sensors on some liquid cooling branches to directly measure the branch flow rate.

[0026] The manifold controller is electrically connected to the aforementioned detection components, controllable execution components, and server management interface. The manifold controller is used to collect sensor data, determine branch topology changes, estimate branch hydraulic characteristics, and generate control commands for branch valves, variable frequency pumps, and bypass valves. Specifically, the manifold controller estimates the branch hydraulic characteristics by superimposing system pressure drops, characterizing the hydraulic characteristics of each liquid-cooled branch as a combined hydraulic impedance with valve opening as a parameter. This combined hydraulic impedance is then divided into two parts as described in this specification: the valve section hydraulic impedance and the cold plate section hydraulic impedance. The valve throttling pressure drop and the pressure drop of the cold plate and pipeline body are characterized separately. The reason for adopting this pressure drop superposition and separation method is that the valve throttling pressure drop changes with the valve opening, while the pressure drop of the cold plate and pipeline body is independent of the valve opening. After separating the two, the manifold controller can accurately determine whether the hydraulic state of the cold plate assembly body is normal under different valve openings, avoiding misjudging the valve throttling effect as cold plate blockage or pipeline abnormality. The server management interface is used to provide the manifold controller with server node power consumption, chip temperature, server online status, server model, cold plate type and target heat dissipation level.

[0027] The aforementioned liquid-cooled manifold, cold plate assembly, quick connector, pressure sensor, flow sensor, temperature sensor, branch valve, bypass valve, variable frequency pump, and server management interface can all adopt the existing hardware structure in the data center liquid-cooled cabinet. The improvement of this application does not lie in changing the above-mentioned hardware structure, but in using the operating data collected by the above-mentioned hardware to establish a manifold hydraulic fingerprint, and generating a protected progressive self-flow equalization control process when adding, removing, or expanding branches.

[0028] Data center liquid cooling manifold self-flow equalization control method, such as Figure 1 As shown, it includes: Step 100: Collect baseline operating data at steady state, calculate hydraulic impedance data based on the baseline operating data, and establish manifold hydraulic fingerprint based on the baseline operating data and hydraulic impedance data.

[0029] Before the server node access, removal, or expansion event occurs, the manifold controller continuously collects data from each sensor at a preset sensor data sampling period. The value of the preset sensor data sampling period is determined by the maximum sampling capability of each sensor and the hydraulic time constant and temperature time constant of the liquid cooling circuit, based on the product specifications provided by the sensor manufacturer and the reference operating condition test data of the liquid cooling circuit. The reason for adopting this sampling period determination method is that the sampling period must simultaneously meet the maximum sampling capability limit of the sensor hardware and the Nyquist sampling condition of the dynamic response of the liquid cooling circuit, so that the collected sensor data can completely reflect the hydraulic and temperature transient processes of the liquid cooling circuit without aliasing distortion. When the connection status of all branches, the branch valve opening of all branches, the total flow rate of the manifold, and the manifold differential pressure do not exceed the corresponding preset steady-state threshold within the preset system stability judgment time window for a continuous duration, it is determined to be a steady state moment. The manifold controller records the set of branches that are currently online and records this set of branches as the existing set of branches before the access event.

[0030] The reason for using the simultaneous satisfaction of the steady-state threshold of the above four types of monitored quantities as the steady-state determination condition is that the steady state of the liquid-cooled manifold requires the hydraulic and thermodynamic states to reach equilibrium simultaneously. Determining steady state based on only a single monitored quantity may lead to misjudgment as steady state when the other monitored quantities are still in transient processes, resulting in subsequent baseline operating data failing to reflect the true equilibrium state of the system. The preset steady-state thresholds are set separately for the four types of monitored quantities: the connection status of all branches, the valve opening of all branches, the total flow rate of the manifold, and the manifold pressure difference. Their values ​​are determined by the measurement noise level of the corresponding sensor and the measured value of the monitored quantity. The allowable fluctuation range of the monitored quantity during operation is determined by statistical analysis of the historical sensor data continuously collected during system operation; the elements in the existing branch set are branch numbers that meet the following conditions: the connection status of the branch is 1, and the online status of the server corresponding to the branch provided by the server management interface is online; the preset system stability judgment time window is determined by the hydraulic time constant and temperature time constant of the liquid cooling circuit through a step response test under reference conditions; the manifold pressure difference is the difference between the supply pressure and the return pressure.

[0031] The manifold controller uses the data collected at this steady-state moment as the baseline operating data. The baseline operating data includes the baseline valve opening, baseline branch inlet temperature, baseline branch outlet temperature, baseline flow rate, manifold baseline differential pressure, baseline bypass flow rate, baseline manifold total flow rate, and baseline server power consumption. For each existing branch within the existing branch set, the manifold controller records its branch valve opening, branch inlet temperature, branch outlet temperature, and corresponding server power consumption at this steady-state moment, and uses these quantities as the baseline valve opening for that branch. The parameters include: door opening, reference branch inlet temperature, reference branch outlet temperature, and reference server power consumption. The manifold controller calculates the reference temperature rise for each existing branch in the following manner: the reference temperature rise is equal to the difference between the reference branch outlet temperature and the reference branch inlet temperature. The manifold controller also records the manifold differential pressure and total manifold flow rate at the steady-state moment, and uses these two as the reference manifold differential pressure and reference manifold total flow rate, respectively. The reference bypass flow rate is the bypass flow rate directly measured by the bypass flow sensor at the steady-state moment.

[0032] In an optional embodiment, for an existing branch equipped with a branch flow sensor, the manifold controller directly obtains the branch flow at steady state as the reference flow of the branch.

[0033] Hydraulic impedance data is calculated based on baseline operating data. The hydraulic impedance data includes combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance. To avoid the inability of a single quadratic model to cover the actual pressure drop characteristics of the cold plate assembly, hose, quick connector, and valve combination in the entire flow range, this embodiment no longer uses the ratio of the square of the flow rate of a single branch to the reference pressure difference of the manifold as the inherent hydraulic impedance of the branch in the entire flow range. Instead, the hydraulic characteristics of the branch under the reference valve opening, reference branch flow rate, and reference pressure difference are characterized as combined hydraulic impedance with valve opening as a parameter.

[0034] The reason for adopting the combined hydraulic impedance characterization method with valve opening as a parameter is that the pressure drop characteristics of the microchannel structure inside the cold plate assembly exhibit different flow transition behaviors in different flow ranges. A single quadratic model is only valid in the fully turbulent range, while the pressure drop deviation in the laminar and transition ranges will lead to distortion in the hydraulic impedance estimation. The combined hydraulic impedance with valve opening as a parameter limits the hydraulic characteristics to a specific operating point, avoiding model errors caused by extrapolation across flow ranges. The combined hydraulic impedance of this branch under the reference valve opening is equal to the quotient obtained by dividing the manifold reference pressure difference by a correction denominator. This correction denominator is equal to the sum of the square of the reference flow rate of this branch and the preset flow rate square correction constant to prevent the denominator from being zero. This combined hydraulic impedance is the series combined impedance of the branch valve, cold plate assembly, quick connector and hose under the reference valve opening. It is only used for comparison between branches under the same branch valve opening, the same valve model and the same pipeline conditions, and for steady-state comparison before and after the same branch. It is not used for extrapolation of the inherent hydraulic impedance between different valve openings.

[0035] The manifold controller simultaneously divides the combined hydraulic impedance of this branch into two parts: valve section hydraulic impedance and cold plate section hydraulic impedance, according to the system pressure drop superposition method, so that the branch hydraulic characteristic identification below can separately characterize the valve throttling pressure drop and the pressure drop of the cold plate and the pipeline body. The valve section hydraulic impedance of this branch at the reference valve opening is calculated as follows: the valve section hydraulic impedance is equal to the quotient obtained by dividing a numerator by a denominator, where the numerator equals 1, and the denominator is equal to the sum of the square of the product of the preset flow coefficient of this branch and the effective flow function value of this branch at the reference valve opening, and the preset flow capacity square correction constant. The cold plate section hydraulic impedance of this branch at the reference valve opening is calculated as follows: the cold plate section hydraulic impedance is equal to the combined hydraulic impedance of this branch at the reference valve opening minus the valve section hydraulic impedance of this branch at the reference valve opening. When the above difference is negative, it is set to zero and the negative difference is recorded as a prompt flag, indicating that the current valve pressure drop is equivalent to the combined pressure drop and therefore cannot be separated. The pressure drop of the cold plate section; the hydraulic impedance of the cold plate section is used to characterize the equivalent hydraulic impedance of the branch body formed by the cold plate assembly, quick connector and hose after deducting the influence of the hydraulic impedance of the valve section; the preset flow square correction constant is a positive real number, its value is much smaller than the square of the minimum branch flow in the operating range, its value is determined by the effective number of bits of the branch flow sensor data and the numerical stability requirements of the controller floating point operation, through numerical analysis at the controller implementation level, and its dimension is the same as the square of the branch flow, and it is only used for denominator correction with the branch flow square as the dimension; the preset flow capacity square correction constant is a positive real number, its dimension is the same as the square of the product of the preset flow coefficient and the effective flow function value of the branch, its value is much smaller than the minimum value of the square of the product of the preset flow coefficient and the effective flow function value in the operating range, its value is determined by the valve flow coefficient calibration accuracy and the numerical stability requirements of the controller floating point operation, through numerical analysis at the controller implementation level, and is used to avoid the denominator being close to zero when calculating the hydraulic impedance of the valve section.

[0036] For example, suppose the first The base flow rate of the branch is The manifold reference pressure difference is The preset squared correction constant for circulation capacity is , No. The preset flow coefficient of the branch is , No. The branch circuit is at the reference valve opening degree The effective flow function takes the value of Then the first Combined hydraulic impedance of branch circuit at reference valve opening Hydraulic resistance of valve section Hydraulic resistance of cold plate section Calculate according to the following formulas: ; ; ; in, For the first The branch circuit is at the reference valve opening degree The combined hydraulic impedance below, For the first The reference valve opening of the branch circuit. For the first The branch circuit is at the reference valve opening degree The hydraulic resistance of the valve section below, For the first The branch circuit is at the reference valve opening degree The hydraulic resistance of the cold plate section below; when hour, Take zero and record the flag indicating that the difference is negative.

[0037] This embodiment uses an electric regulating valve with equal percentage flow characteristics. The corresponding effective flow function is defined segmentally according to the interval of the branch valve opening. The purpose of segmentation is to characterize the fully closed interval, the uncontrollable interval below the minimum controllable opening, the equal percentage adjustable interval, and the fully open saturation interval separately. The reason for using an electric regulating valve with equal percentage flow characteristics is that the equal percentage characteristic makes the rate of change of the valve's flow at any opening proportional to the current flow, thereby keeping the control gain consistent within the full opening range and avoiding the problem of excessive control gain leading to flow oscillation in the small opening interval or excessive control gain leading to slow regulation in the large opening interval. The reason for segmenting the effective flow function is that the actual valve has leakage in the fully closed interval, a nonlinear dead zone below the minimum controllable opening, and flow capacity saturation in the fully open state. The flow characteristics in the above intervals deviate from the equal percentage relationship. Segmentation ensures that the effective flow function can accurately reflect the actual flow capacity of the valve in each interval.

[0038] When the branch valve opening is less than the preset valve fully closed judgment opening, the effective flow function value is taken as the preset valve closed state leakage flow function value. The preset valve closed state leakage flow function value is a non-negative real number, determined by dividing the maximum allowable leakage flow in the closed state provided by the valve manufacturer by the product of the preset flow coefficient of the branch and the arithmetic square root of the manifold reference pressure difference, and clamped at zero as the lower limit. When the branch valve opening is not less than the preset valve fully closed judgment opening and less than the preset valve minimum controllable opening, the effective flow function value is defined as follows: the normalized progress of the branch valve opening from the preset valve fully closed judgment opening to the preset valve minimum controllable opening is used as the weight, and the leakage flow in the preset valve closed state is taken as the value. A linear interpolation is performed between the leakage flow function value and the preset percentage function value at the minimum controllable valve opening. The interpolation result is used as the effective flow function value within that interval. The preset percentage function value at the minimum controllable valve opening is equal to the power of the ratio of the minimum controllable valve opening to the maximum valve opening minus 1, with the valve adjustable ratio as the base. When the branch valve opening is not less than the preset minimum controllable valve opening and not greater than the maximum valve opening, the effective flow function value is given according to the following percentage relationship: the effective flow function value under the percentage relationship is equal to the power of the ratio of the branch valve opening to the maximum valve opening minus 1, with the valve adjustable ratio as the base.

[0039] When the valve opening of the branch is greater than the maximum valve opening, the effective flow function value is saturated and clamped according to the equal percentage function value at the maximum valve opening. When back-calculating the valve opening using the above effective flow function value, the back-calculation result is limited to the effective domain according to the following allowable opening range. The back-calculation result is not less than the preset minimum controllable valve opening and not greater than the maximum valve opening. When the intermediate result obtained from the back-calculation falls below the preset minimum controllable valve opening, the back-calculated valve opening is taken as the preset minimum controllable valve opening. When the intermediate result obtained from the back-calculation falls above the maximum valve opening, the back-calculated valve opening is taken as the maximum valve opening.

[0040] For example, suppose the first The branch valve opening degree of the branch is The preset valve opening degree is determined to be completely closed. The preset minimum controllable valve opening is The maximum valve opening is The preset valve adjustable ratio is The preset leakage flow function value for the valve closed state is Then the first Effective flow function of branch Define segments as follows: when hour, ; when hour, ; when hour, ; when hour, .

[0041] in, The preset valve minimum controllable opening is determined by an equal percentage function. Specifically, the preset valve adjustability ratio is determined by the equal percentage flow characteristic curve provided by the valve manufacturer, and more specifically, by the ratio of the relative flow rate in the fully open state to the relative flow rate in the minimum controllable opening state. The preset maximum valve opening is the maximum permissible opening of the valve, determined by the product specifications provided by the valve manufacturer. The preset minimum controllable valve opening is the minimum controllable opening marked by the valve manufacturer on the equal percentage flow characteristic curve, also determined by the product specifications provided by the valve manufacturer. The preset valve fully closed determination opening is a real number greater than zero and less than the preset minimum controllable valve opening; its value is determined by the valve actuator's opening feedback dead zone in the closed state and the valve's leakage in the closed state, calibrated through valve closed state tests under reference operating conditions.

[0042] In an optional embodiment, for an existing branch without a branch flow sensor, the manifold controller estimates the reference flow rate of the branch as follows: the estimated reference flow rate is equal to the product of the branch's preset flow coefficient, the effective flow function value of the branch at the reference valve opening, and the arithmetic square root of the manifold reference pressure difference. The preset flow coefficient of the branch is determined by the valve model, pipe diameter, and reference operating condition calibration. Specifically, for each combination of valve model and pipe diameter, several known manifold pressure differences are applied under the reference operating condition, and the corresponding branch flow rate is measured. The flow coefficient is then calculated by using the product relationship between the branch flow rate, the effective flow function value, and the arithmetic square root of the manifold pressure difference. The effective flow function of the branch represents the effective flow capacity of the branch after valve opening normalization.

[0043] For existing branches without branch flow sensors, the manifold controller calculates the combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance of the branch at the reference valve opening, using the same caliber as the existing branches with branch flow sensors described above. Specifically, the combined hydraulic impedance of the branch at the reference valve opening is equal to the quotient obtained by dividing the manifold reference pressure difference by a correction denominator, where the correction denominator is equal to the sum of the square of the estimated reference flow rate of the branch and the flow rate square correction constant; the valve section hydraulic impedance of the branch at the reference valve opening is equal to the quotient obtained by dividing the numerator by the denominator, where the numerator equals 1 and the denominator equals the branch's... The sum of the square of the product of the preset flow coefficient and the effective flow function value of the branch under the reference valve opening, and the preset flow capacity square correction constant; the hydraulic impedance of the cold plate section of the branch under the reference valve opening is equal to the difference between the combined hydraulic impedance of the branch under the reference valve opening and the hydraulic impedance of the valve section of the branch under the reference valve opening. When the above difference is negative, it is set to zero and the negative difference is recorded as a prompt flag; the combined hydraulic impedance, valve section hydraulic impedance and cold plate section hydraulic impedance are only used for comparison between branches under the same branch valve opening, the same valve model and the same pipeline conditions, and for steady-state comparison before and after the same branch.

[0044] To ensure consistency in the subsequent descriptions, the baseline flow rate of each existing branch will be recorded as a unified variable. When the branch is equipped with a branch flow sensor, the unified variable will be the baseline flow rate directly measured by the sensor. When the branch is not equipped with a branch flow sensor, the unified variable will be the baseline flow rate obtained by the estimation method described above.

[0045] The server management interface provides the manifold controller with the minimum safe cooling flow rate for each server node in the existing branch set. This minimum safe cooling flow rate is a preset parameter, determined by the server node manufacturer for each combination of server model and cold plate type. It is based on the minimum coolant flow rate required for the cold plate assembly to maintain the chip junction temperature below the upper limit of the allowable operating temperature under rated power consumption. The parameter is calibrated through thermal performance tests of the cold plate assembly under reference operating conditions and is pre-stored in the configuration database of the server management interface. When a server node is connected, it is reported to the manifold controller through the server management interface.

[0046] At this point, the manifold controller obtains the manifold hydraulic fingerprint prior to the access event. This manifold hydraulic fingerprint includes the existing branch set, the reference valve opening of each existing branch, the reference flow rate of each existing branch, the combined hydraulic impedance of each existing branch at the reference valve opening, the valve section hydraulic impedance of each existing branch at the reference valve opening, the cold plate section hydraulic impedance of each existing branch at the reference valve opening, the manifold reference pressure difference, the reference manifold total flow rate, the reference bypass flow rate, the reference temperature rise of each existing branch, and the reference server power consumption corresponding to each existing branch. This manifold hydraulic fingerprint is stored in the storage module of the manifold controller and is used for judgment and calculation in steps 200 to 500. The purpose of establishing the manifold hydraulic fingerprint is to solidify and store the complete hydraulic and thermal state of the liquid-cooled manifold during steady-state operation in the form of structured data, so that when a branch topology change event occurs subsequently, the manifold controller can use this fingerprint as a reference to perform difference comparison, thereby accurately quantifying the degree of influence of the topology change on the manifold flow distribution and generating a control strategy accordingly.

[0047] Step 200: Monitor the discrimination parameters of each branch, determine whether a branch topology change event has occurred based on the discrimination parameters, and determine the corresponding target branch as a newly added branch, removed branch, or expanded branch based on the event type of the branch topology change event. Calculate the lower limit of the protection flow rate based on the manifold hydraulic fingerprint and apply change rate constraints to the controllable actuators, specifically as follows... Figure 2 As shown.

[0048] The manifold controller continuously monitors the discriminant parameters of each branch, including the branch connection status, the reporting status of the branch location identifier code, the total manifold flow rate, the manifold differential pressure, the branch valve opening, the inlet and outlet liquid temperature difference of each branch, and the online status of the corresponding server, server node power consumption, and chip temperature. The reason for selecting the above multi-dimensional discriminant parameters as monitoring objects is that branch topology change events will simultaneously cause changes in connection status, flow redistribution, differential pressure fluctuations, and temperature responses at the physical level. A single discriminant parameter may be missed due to sensor failure or reporting delay. The joint monitoring of multi-dimensional discriminant parameters enables the manifold controller to capture topology change events in a timely manner when any abnormality occurs in any dimension.

[0049] When one of the following preset explicit criteria is met, the manifold controller determines that a branch topology change event has occurred. Branch topology change events include adding a new branch, removing an existing branch, and expanding branch hot load. When the connection status of the nth branch changes from 0 to 1, or the online status of the server corresponding to the nth branch changes from offline to online, or the branch location identifier code corresponding to the nth branch changes from unreported to reported, the manifold controller determines that the branch topology change event of the nth branch is adding a new branch, and the branch number of the added branch is n. When the connection status of the kth branch changes from 1 to 0, or the online status of the server corresponding to the kth branch changes from online to offline, or the branch location identifier code corresponding to the kth branch changes from reported to unreported, the manifold controller determines that the branch topology change event of the kth branch is removing an existing branch, and the branch number of the removed branch is k.

[0050] When an existing branch continuously meets one of the following conditions within a preset expansion determination time window, the manifold controller determines that the existing branch has undergone branch thermal load expansion and records the existing branch as an expansion branch: the difference between the current value of the server node power consumption corresponding to the branch and the baseline server power consumption exceeds a preset server node power consumption expansion threshold; the current value of the chip temperature corresponding to the branch exceeds a preset chip temperature expansion threshold; or the target heat dissipation level corresponding to the branch provided by the server management interface changes; wherein, the value of the preset expansion determination time window is determined by the time scale of the transient fluctuation of server node power consumption and the liquid cooling loop temperature time constant, calibrated using historical data of server node power consumption changes under reference operating conditions; the preset server node... The power consumption expansion threshold is determined by calibrating the server node's rated power consumption range and the heat dissipation margin of the cold plate assembly under the reference flow rate through server node power consumption expansion tests under reference operating conditions. The preset chip temperature expansion threshold is determined by calibrating the chip's allowable operating temperature range provided by the chip manufacturer and the chip temperature upper limit specified by the target heat dissipation level through server node power consumption expansion tests under reference operating conditions. The preset branch temperature difference expansion threshold is determined by calibrating the measurement noise levels of the inlet and outlet temperature sensors, the allowable fluctuation range of the reference temperature rise during operation, and the engineering margin between the upper limit of the coolant temperature rise specified by the target heat dissipation level and the reference temperature rise through server node power consumption expansion tests under reference operating conditions.

[0051] When the quick-connect connection status signal, branch location identifier code, and server online status are not promptly reported or are delayed, the manifold controller executes a preset implicit judgment condition. When the preset implicit judgment condition is met, it is determined that the branch topology change event has occurred. The reason for setting the implicit judgment condition is that in actual data center operation, the quick-connect microswitch may fail due to mechanical wear, the branch location identifier module may be delayed in reporting due to communication link congestion, and the server management interface may fail to update the online status in a timely manner due to software abnormalities. When the above explicit judgment signals are unavailable, the manifold controller still needs to identify the topology change based on the abnormal characteristics of the hydraulic and thermal levels. To ensure the robustness of the control system, in the implicit decision condition, the manifold controller first calculates the residual of the total flow of the manifold branch in the following way, so that the residual is no longer affected by the bypass flow. The residual of the total flow of the manifold branch is equal to the current total flow of the manifold minus the current bypass flow directly measured by the bypass flow sensor, and then minus the difference between the reference total flow of the manifold and the reference bypass flow. The reason for deducting the bypass flow from the total flow of the manifold in this calculation method is that the bypass valve may change its opening due to temperature regulation needs during normal operation, resulting in changes in the bypass flow. If the bypass flow is not deducted, the normal adjustment action of the bypass valve will be misjudged as a branch topology change event.

[0052] For example, suppose the current total manifold flow is The current bypass flow rate directly measured by the bypass flow sensor is The baseline manifold total flow rate is The baseline bypass flow rate is The residual of total flow in the manifold branch Calculate using the following formula: ; The manifold controller then calculates the manifold differential residual as follows: the manifold differential residual is equal to the difference between the current manifold differential and the manifold reference differential.

[0053] The manifold controller uses the manifold hydraulic fingerprint saved in step 100 to calculate the predicted change in total manifold branch flow that can be explained by changes in the opening of existing branch valves, as follows: The purpose of calculating this predicted change is to separate the flow change caused by normal adjustment of the opening of existing branch valves from the residual total flow of the manifold branches, so that the remaining unexplained flow residual can accurately reflect the flow anomaly caused by branch topology change events, and avoid misjudging the normal adjustment action of existing branch valves as a topology change event; For each existing branch in the set of existing branches, the following two calculations are first performed. The first value is equal to the product of the preset flow coefficient of the branch, the effective flow function value of the branch at the current valve opening, and the arithmetic square root of the current manifold pressure difference; the second value is equal to the product of the preset flow coefficient of the branch, the effective flow function value of the branch at the reference valve opening, and the arithmetic square root of the reference manifold pressure difference; the manifold controller calculates the difference between the first value and the second value for each existing branch, and then sums the differences for all branches in the set of existing branches. The summation result is the predicted change in the total flow of the manifold branches.

[0054] For example, suppose the existing set of branches is , No. The preset flow coefficient of the existing branch is , No. The existing branch is at the current valve opening. The effective flow function takes the value of The current manifold pressure differential is , No. The existing branch line at the reference valve opening degree The effective flow function takes the value of The manifold reference pressure difference is The predicted change in total flow rate of the manifold branches Calculate using the following formula: ; When the absolute value of the difference between the residual total flow of a manifold branch and the predicted change in total flow of the manifold branch is greater than the preset threshold for judging the change in total flow of the manifold, or the absolute value of the residual pressure difference of the manifold is greater than the preset threshold for judging the change in pressure difference of the manifold, or when the absolute value of the difference between the inlet and outlet liquid temperature difference of an existing branch and the reference temperature rise exceeds the preset threshold for branch temperature difference expansion within a time window that lasts for a preset duration, the manifold controller determines that the preset implicit judgment condition is met. After the event type of the implicit judgment condition is determined, the manifold controller determines it in the following manner. Specific branch number; when the branch location identifier of a branch changes from unreported to reported within the duration of the segment, the manifold controller determines that the branch topology change event of that branch is a new branch access, and the manifold controller uses the branch number of that branch as the branch number of the new branch; when the branch location identifier of a branch changes from reported to unreported within the duration of the segment, the manifold controller determines that the branch topology change event of that branch is an existing branch removal, and the manifold controller uses the branch number of that branch as the branch number of the removed branch.

[0055] When the branch number corresponding to the state change of the quick-connect micro switch within the specified duration has been reported through the server management interface, the manifold controller determines the branch topology change event type of the branch based on the direction of the state change of the quick-connect micro switch. Specifically, when the quick-connect micro switch changes from the open state to the closed state, the manifold controller determines that the branch topology change event of the branch is a new branch access, and uses the branch number reported by the server management interface as the branch number of the new branch; when the quick-connect micro switch changes from the closed state to the open state, the manifold controller determines that the branch topology change event of the branch is an existing branch removal, and uses the branch number reported by the server management interface as the branch number of the removed branch.

[0056] When neither the branch location identifier code nor the quick-connect microswitch is reported, the manifold controller identifies the branch number using branch temperature mutations and branch valve opening mutations as follows: For each existing branch in the existing branch set, the absolute value of the difference between its inlet / outlet liquid temperature difference and the reference temperature rise, as well as the absolute value of the difference between its branch valve opening and the reference valve opening, are calculated within the duration of this segment. If the absolute value of the difference between the inlet / outlet liquid temperature difference and the reference temperature rise exceeds the preset branch temperature difference expansion threshold or the absolute value of the difference between its branch valve opening and the reference valve opening exceeds the threshold within the duration of this segment, the controller will detect any instances where the absolute value of the difference between the inlet / outlet liquid temperature difference and the reference temperature rise exceeds the preset branch temperature difference expansion threshold or the absolute value of the difference between the branch valve opening and the reference valve opening exceeds the threshold threshold. If the absolute value of the difference in valve opening exceeds the preset valve opening mutation threshold, and the corresponding values ​​of other existing branches within the duration of this segment do not exceed the corresponding threshold, the manifold controller uses the branch number of this branch as the candidate branch number for the event to be confirmed. The event type is then determined after the server management interface further reports the server online status, target heat dissipation level, or branch location identifier. If no single branch meets the above conditions, the manifold controller records the branch number as not uniquely locating, marks this implicit judgment condition as a branch number pending confirmation, and proceeds according to the following strategy. The manifold controller maintains the current manifold differential pressure and the valve openings of each branch, waiting for the branch location identifier, quick-connect microswitch, or server management interface to report the branch number before proceeding to steps 300 and 400. If the waiting time exceeds the preset branch number waiting time and no branch number is obtained, the manifold controller reallocates the remaining branch target flow according to the server node power consumption weight of all branches in the existing branch set. Specifically, for each existing branch in the existing branch set, the reallocated target flow of that branch is equal to the following power consumption weight and the total cooling capacity of the existing branch. However, the power consumption weight is equal to the product of the power consumption of the server node corresponding to the branch and the sum of the power consumption of the server nodes corresponding to all branches in the existing branch set. The total cooling demand flow of the existing branch is equal to the sum of the cooling demand flow of each branch calculated according to the heat balance caliber of each branch in the existing branch set. The cooling demand flow of each branch is equal to the product of the power consumption of the server node corresponding to the branch and the product of the preset coolant density, the preset coolant specific heat capacity and the preset allowable coolant temperature rise, and the product of the preset liquid capture rate.

[0057] The manifold controller does not adjust the valve opening of newly added branch connections individually until the branch number is confirmed before proceeding to steps 300 and 400. The preset valve opening sudden change threshold is determined by statistical analysis of historical sensor data continuously collected during system operation, based on the measurement noise level of the valve opening detection module and the allowable fluctuation range of the reference valve opening. The preset branch number waiting time is determined by calibration using historical data of topology change events under reference operating conditions, based on the maximum allowable delay of the branch location identifier code reported by the server management interface and the liquid cooling circuit temperature time constant. The preset manifold total flow change judgment threshold is determined by statistical analysis of historical sensor data continuously collected during system operation, based on the measurement noise level of the total flow sensor and the allowable fluctuation range of the reference manifold total flow. The preset manifold differential pressure change judgment threshold is determined by statistical analysis of historical sensor data continuously collected during system operation, based on the measurement noise levels of the supply and return pressure sensors and the allowable fluctuation range of the manifold differential pressure.

[0058] The manifold controller uses the identified event type and corresponding branch number as input for subsequent control steps. When the identified event is the removal of an existing branch, it proceeds to the branch removal process in step 500. When the identified event is the access of a new branch, it continues to execute the subsequent content of this step, and then executes steps 300 and 400 in sequence. When the identified event is the expansion of branch thermal load, since the branch being expanded is a branch in the existing branch set that is already in online operation, its cold plate assembly has been pre-filled with liquid and its hydraulic characteristics have been established as a baseline in step 100, there is no need to re-identify the hydraulic characteristics. Therefore, it continues to execute the subsequent content of this step, skipping the low-disturbance trial liquid supply step for the new branch in step 300, and directly enters step 400 to execute the target flow redistribution process for the expanded branch as described below.

[0059] After confirming a branch topology change event, the manifold controller first enters the existing branch protection mode. The purpose of entering the existing branch protection mode is to set a lower limit value for the flow of each existing branch during the branch topology change event processing, so as to ensure that no control action will cause the coolant flow of the existing branch to drop below the minimum level required for the cold plate assembly to maintain the safe operation of the chip. This ensures the cooling safety of the existing server nodes during the process of adding new branches or increasing the flow of expanded branches.

[0060] For each existing branch in the existing branch set, the manifold controller calculates the lower limit of the protection flow rate for that branch based on the reference flow rate and minimum safe cooling flow rate obtained in step 100, as follows: First, calculate the following two values: the first value is equal to the minimum safe cooling flow rate corresponding to that branch, and the second value is equal to the product of 1 minus the preset maximum allowable branch flow rate drop ratio and the reference flow rate of that branch; the lower limit of the protection flow rate is the maximum value of the above two values; the reason for taking the maximum value of the two values ​​as the lower limit of the protection flow rate is that the first value ensures... The branch flow rate is not lower than the absolute minimum flow rate required by the cold plate assembly to maintain the safe operation of the chip. The second value ensures that the drop in branch flow rate relative to the reference flow rate does not exceed the allowable range. The maximum value of the two values ​​is taken so that the lower limit of the protection flow rate simultaneously meets the stricter of the absolute safety constraint and the relative stability constraint. The preset maximum allowable branch flow rate drop ratio is a real number greater than 0 and less than 1. The specific value within this range is determined by the liquid-cooled data center operator based on the engineering margin requirements between the minimum safe cooling flow rate of the cold plate assembly and the existing branch reference flow rate, through calibration using hydraulic test data under reference operating conditions.

[0061] The manifold controller applies rate-of-change constraints to the output commands of the variable frequency pump, bypass valve, and branch valves, including manifold differential pressure rate-of-change constraints and valve opening rate-of-change constraints. The purpose of these constraints is that the pressure resistance of the cold plate assemblies, quick-connect fittings, and hoses in the liquid-cooled manifold is limited. Sudden changes in manifold differential pressure can cause water hammer in the pipeline, potentially leading to quick-connect fitting seal failure or damage to the microchannel structure inside the cold plate assemblies. Simultaneously, sudden changes in valve opening can cause step disturbances in branch flow, causing the existing branch flow to momentarily drop below the protection flow limit. Applying rate-of-change constraints ensures that all control actions are executed at a limited rate, thereby controlling hydraulic transient disturbances within the tolerance range of the pipeline and cold plate assemblies. The manifold differential pressure rate-of-change constraint includes ensuring that the absolute value of the derivative of the manifold differential pressure with respect to time does not exceed a preset minimum value. The manifold differential pressure change rate and valve opening change rate constraints include: for each branch in the branch set consisting of the existing branch set and the newly added branch, the absolute value of the derivative of the branch valve opening with respect to time is not greater than the preset maximum valve opening change rate; for branch thermal load expansion events, the above change rate constraints apply to all branches in the existing branch set, including the expansion branch itself; the preset maximum manifold differential pressure change rate is determined by calibration through a step response test under reference operating conditions, based on the pressure resistance rating of the liquid-cooled manifold, the dynamic response characteristics of the variable frequency pump, and the stability requirements of the coolant circuit; the preset maximum valve opening change rate is determined by the rated stroke time of the branch valve and the maximum adjustment rate of the valve actuator, based on the dynamic response curve provided by the valve manufacturer.

[0062] Specifically, when the manifold controller issues control commands according to a preset control cycle, the change in manifold pressure difference between two adjacent control cycles is defined as the difference between the current control cycle's manifold pressure difference and the previous control cycle's manifold pressure difference. The absolute value of this change is not greater than the product of the maximum manifold pressure difference change rate and the length of the control cycle. The change in the branch valve opening of each branch between two adjacent control cycles is defined as the difference between the current control cycle's branch valve opening and the previous control cycle's branch valve opening. The absolute value of this change is not greater than the product of the maximum valve opening change rate and the length of the control cycle. The preset control cycle is determined based on the fastest response time of the variable frequency pump, bypass valve, and branch valves, as well as the computation time required for the manifold controller to perform one complete control law calculation, according to the dynamic response curve provided by the controllable actuator manufacturer and the computation timing analysis at the controller implementation level.

[0063] The manifold controller uses the lower limit of the protection flow rate of each branch in the existing branch set, as well as the manifold differential pressure change rate constraint and the valve opening change rate constraint, as the mandatory constraint conditions for subsequent control links.

[0064] In an optional embodiment, when the manifold controller identifies multiple branch topology change events within the same system stability determination time window, the manifold controller determines the processing order according to the event type and the degree of traffic impact. Specifically, existing branch removal events are sorted and processed in descending order of the traffic proportion of the corresponding removed branch; new branch access events are sorted and processed in ascending order of the initial target traffic value corresponding to the trial traffic proportion; and branch hot load expansion events are sorted and processed in descending order of the increase in server node power consumption. When removal, addition, and expansion events coexist, removal events are processed first to eliminate the risk of increased manifold pressure difference, followed by addition and expansion events. After adjusting the target traffic and updating the current branch set for each branch topology change event, the next branch topology change event is processed.

[0065] Step 300: Based on the rate of change constraint, perform trial fluid supply on the newly added branch. Calculate the hydraulic impedance data of the newly added branch under the trial fluid supply, and calculate the disturbance coefficient and hydraulic identification reliability coefficient, as detailed below. Figure 3 As shown.

[0066] For the newly identified branch in step 200, the manifold controller performs a low-disturbance trial fluid supply to the new branch. The purpose of performing the low-disturbance trial fluid supply is that the actual hydraulic characteristics of the cold plate assembly of the new branch are unknown when it is connected, and there may be abnormal states such as air bubble retention, insufficient pre-filled fluid, or cold plate blockage. If the valve of the new branch is directly opened to the target opening, the branch may occupy too much flow or the manifold pressure difference may change suddenly due to the abnormal hydraulic impedance of the new branch. The low-disturbance trial fluid supply uses a small proportion of the target flow as the trial flow. Under the condition of minimizing the impact on the flow distribution of the existing branches, the actual hydraulic characteristic data of the new branch are obtained, providing reliable hydraulic parameter input for the subsequent generation of the progressive target flow sequence.

[0067] The low-disturbance trial coolant supply includes the manifold controller first estimating the initial target flow rate of the new branch based on the server node power consumption and target heat dissipation level of the server node corresponding to the new branch provided by the server management interface. The initial target flow rate is equal to the quotient obtained by dividing the power consumption of the server node corresponding to the new branch by a denominator, which is equal to the product of the preset coolant density, the preset coolant specific heat capacity, and the preset allowable coolant temperature rise. Among them, the preset coolant density and the preset coolant specific heat capacity are both physical property parameters of the coolant, which are obtained from the physical property parameter table provided by the coolant supplier under reference operating conditions. The preset allowable coolant temperature rise is determined by the target heat dissipation level. Specifically, it is determined by the upper limit of coolant temperature rise specified by the server management interface for each target heat dissipation level. Considering factors such as air cooling sharing, liquid cooling capture rate, thermal resistance from chip to cold plate, changes in coolant properties with temperature, transient power consumption of server nodes, and safe load reduction strategies, the manifold controller further multiplies the initial target flow rate calculated according to the thermal balance caliber by the inverse of the preset liquid cooling capture rate as an engineering correction to the initial target flow rate of the closed loop, so that the initial target flow rate of the closed loop reflects the actual heat dissipation undertaken by the liquid cooling loop.

[0068] The preset liquid-cooled capture rate is a real number greater than 0 and not greater than 1, determined by the server node's air-liquid hybrid heat dissipation design parameters and the heat dissipation distribution test of the coolant circuit under reference operating conditions; the reciprocal of the liquid-cooled capture rate is equal to the quotient obtained by dividing 1 by the preset liquid-cooled capture rate; the result of this product is referred to as the initial value of the target flow of the newly added branch n, and it is only used as the initial value of the closed-loop control, not as the final target flow. The final target flow is updated by step 400 based on the server node power consumption, branch outlet liquid temperature feedback and target heat dissipation level.

[0069] The manifold controller sets a preset test flow ratio, which is a real number greater than 0 and less than 0.3. The specific value within this range is determined by the engineering ratio between the total allowable flow redistribution of existing branches during the new branch connection process and the initial target flow value of the new branch, calibrated through hydraulic tests under reference operating conditions. Under the valve opening change rate constraint defined in step 200, the manifold controller increases the branch valve opening of the new branch n from the closed state to the test opening at the maximum valve opening change rate, and maintains this test opening for a preset test time. The preset test time is based on the higher of the hydraulic time constant and the temperature time constant. The setting, namely, the preset test time is not less than the lower limit of the hydraulic test time determined by the hydraulic time constant of the liquid cooling circuit, and not less than the lower limit of the temperature test time determined by the temperature time constant of the liquid cooling circuit and the response time of the temperature sensor, so that the inlet and outlet liquid temperature difference and the branch flow rate have entered a thermal steady state at the end of the test time; the specific value of the preset test time is determined by the valve response time of the new branch n, the hydraulic time constant and the temperature time constant of the liquid cooling circuit, through a step response test under reference operating conditions; the value of the test opening is less than the target valve opening of the new branch n; the target valve opening is the valve opening required for the new branch n to reach the initial value of the target flow rate, which is determined by back calculation from the valve flow characteristics.

[0070] The trial opening is determined as follows: First, calculate the intermediate value, which is equal to the product of the trial flow ratio and the initial target flow value, and then divide it by the quotient obtained by the product of the preset flow coefficient of the new branch n and the arithmetic square root of the manifold reference pressure difference. The trial opening is equal to the function value obtained by substituting this intermediate value as the independent variable into the inverse function of the effective flow function, and the effective domain is limited according to the allowable opening range calculated by the above effective flow function. When calculating the trial opening, the result is not less than the preset minimum controllable valve opening and not greater than the maximum valve opening. When the intermediate result obtained by the inverse calculation falls below the preset minimum controllable valve opening, the trial opening is taken as the preset minimum controllable valve opening. When the intermediate result obtained by the inverse calculation falls above the maximum valve opening, the trial opening is taken as the maximum valve opening. The preset flow coefficient of the new branch n is determined by its valve model, specifically by the nominal flow coefficient provided by the valve manufacturer for the valve model under reference operating conditions.

[0071] During the trial period, the manifold controller collects the following trial phase data at a preset sensor data sampling period. The trial phase data includes the total manifold flow rate, bypass flow rate, manifold differential pressure, inlet and outlet liquid temperature difference of each existing branch, inlet and outlet liquid temperature change of the newly added branch n, and valve response time of the newly added branch n. Among them, the bypass flow rate during the trial phase is the bypass flow rate directly measured by the bypass flow sensor during the trial phase. The inlet and outlet liquid temperature change of the newly added branch n during the trial phase is equal to the difference between the outlet liquid temperature of the newly added branch n during the trial phase and the inlet liquid temperature of the newly added branch n during the trial phase.

[0072] In an optional embodiment, for an existing branch equipped with a branch flow sensor, the manifold controller directly acquires the branch flow during the trial phase.

[0073] In an optional embodiment, for an existing branch without a branch flow sensor, the manifold controller estimates the branch flow during the trial phase in the following manner: the estimated branch flow during the trial phase is equal to the product of the branch's preset flow coefficient, the effective flow function value of the branch at the corresponding valve opening during the trial phase, and the arithmetic square root of the manifold pressure difference during the trial phase.

[0074] For a newly added branch n, if a branch flow sensor is configured, the branch flow of the newly added branch n during the trial phase is directly obtained; if no branch flow sensor is configured, the manifold controller estimates the branch flow of the newly added branch n during the trial phase according to the flow conservation principle as follows, and explicitly includes the bypass flow in the flow conservation caliber, avoiding the inclusion of the bypass flow in the newly added branch flow. The reason for using the flow conservation method to estimate the newly added branch flow is that the valve opening of the newly added branch during the trial phase is in the small opening range. At this time, the nonlinearity of the valve flow characteristics is high. The flow estimation error by directly using the valve flow coefficient and the effective flow function is greater than the estimation error of the flow conservation method. The flow conservation method only relies on the measurement accuracy of the manifold total flow sensor and the bypass flow sensor, as well as the estimation accuracy of the existing branch flow. Under the condition that there are many existing branches and the estimation errors of each branch are independent of each other, the overall estimation accuracy is better than the single branch valve characteristic back calculation method.

[0075] The reason for including bypass flow in the flow conservation calculation is that the bypass pipeline may carry a certain flow during the trial phase due to the adjustment of the bypass valve opening. If the bypass flow is not deducted from the total manifold flow, it will be mistakenly included in the flow of the new branch, resulting in an underestimation of the hydraulic impedance of the new branch. First, the branch flow of all existing branches in the existing branch set during the trial phase is summed to obtain the sum of existing branch flow. Then, the difference between the total manifold flow during the trial phase and the bypass flow during the trial phase, and then the sum of existing branch flow, is taken as the estimated flow of the new branch n during the trial phase. When the above difference is negative, it is taken as zero and the new branch is recorded. An abnormal flag is added to the branch flow estimation, so that the branch flow estimation results in this trial phase are not used in the subsequent hydraulic impedance judgment of the cold plate section. Instead, step 400 is executed according to the process of reducing the incremental asymptotic coefficient and re-trialing as described below. To unify the description of the following content, the branch flow of the newly added branch n in the trial phase is recorded as a unified variable. When the newly added branch is equipped with a branch flow sensor, the unified variable is the branch flow of the trial phase directly measured by the sensor. When the newly added branch is not equipped with a branch flow sensor, the unified variable is the branch flow of the trial phase obtained by the above estimation method.

[0076] Based on the data from the aforementioned trial phase, the manifold controller calculates the combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance of the new branch n at the trial opening using the following method, according to the system pressure drop superposition method. This avoids misjudging the valve throttling pressure drop at the trial opening as the pressure drop of the cold plate assembly, quick connector, or hose body. The combined hydraulic impedance of the new branch n at the trial opening is equal to the quotient obtained by dividing the manifold pressure difference during the trial phase by a correction denominator. This correction denominator is equal to the sum of the square of the branch flow rate of the new branch n during the trial phase and the flow rate square correction constant. This combined hydraulic impedance is the series combined impedance of the branch valve, cold plate assembly, quick connector, and hose of the new branch n at the trial opening. The valve section hydraulic impedance of the new branch n at the trial opening is calculated as follows: the valve section hydraulic impedance is equal to the quotient obtained by dividing a numerator by a denominator. The numerator is equal to 1, and the denominator is equal to the preset flow coefficient of the new branch n and the new... The effective flow function of the new branch n at the test opening is the sum of the square of the product of the two values ​​and the preset square correction constant for the flow capacity. The hydraulic impedance of the cold plate section of the new branch n at the test opening is calculated as follows: the hydraulic impedance of the cold plate section is equal to the difference between the combined hydraulic impedance of the new branch n at the test opening and the hydraulic impedance of the valve section of the new branch n at the test opening. When the above difference is negative, it is set to zero and a negative indicator flag is recorded to indicate that the valve pressure drop at the current test opening is equivalent to the combined pressure drop, thus making it impossible to separate the cold plate section pressure drop. This hydraulic impedance of the cold plate section is used to characterize the hydraulic characteristics of the cold plate assembly, quick connector and hose in the new branch after deducting the influence of the valve section hydraulic impedance. In subsequent judgment, it is compared with the upper and lower limits of the hydraulic impedance of the cold plate section calibrated under the same cold plate model, the same test opening, the same valve model and the same pipeline conditions.

[0077] The manifold controller calculates the disturbance coefficient of the new branch n on the existing branches in the following manner: The purpose of calculating the disturbance coefficient is to quantify the total flow drop caused by the new branch to the set of existing branches when it obtains a unit flow during the trial phase. This coefficient directly reflects the degree of threat to the cooling safety of the existing branches by the access of the new branch. The larger the disturbance coefficient, the stronger the flow preemption effect of the new branch on the existing branches. The subsequent progressive target flow sequence needs to suppress this preemption effect with more control stages and smaller flow increments per stage. First, for each existing branch in the set of existing branches, calculate the difference between the base flow of the branch and the branch flow during the trial phase. When the difference is positive, take the difference; when the difference is zero or negative, take zero. The result is recorded as the flow drop of the branch.

[0078] The manifold controller then sums the flow drop of all existing branches in the existing branch set, and divides the sum by a correction denominator to obtain a disturbance coefficient. The correction denominator is equal to the sum of the branch flow of the new branch n during the trial phase and a preset branch flow correction constant to prevent the denominator from being zero. This disturbance coefficient represents the total flow drop of all branches in the existing branch set when the new branch obtains a unit flow. The preset branch flow correction constant is a positive real number, and its value is much smaller than the minimum branch flow in the operating range. Its value is determined by numerical analysis at the controller implementation level based on the effective number of bits of the branch flow sensor data and the numerical stability requirements of the controller's floating-point operations. Its dimension is the same as that of the branch flow and it is only used for denominator correction when the dimension is branch flow or total manifold flow.

[0079] The manifold controller determines the hydraulic impedance of the cold plate section of the newly added branch n at the test opening to avoid misjudging the valve throttling pressure drop at the test opening as a hydraulic anomaly of the cold plate assembly, quick connector, or hose. When the indicator flag for a negative hydraulic impedance difference in the cold plate section of the newly added branch n is set, the manifold controller determines that the valve pressure drop at the current test opening is equivalent to the combined pressure drop, making it impossible to separate the cold plate section pressure drop. It skips the hydraulic anomaly judgment and proceeds to step 400, which describes the process of reducing the incremental asymptotic coefficient and retesting. When the indicator flag for a negative hydraulic impedance difference in the cold plate section of the newly added branch n is not set, the manifold controller determines the issue as follows: When the newly added... When the hydraulic impedance of the cold plate section of branch n at the test opening is less than the preset lower limit of the hydraulic impedance of the cold plate section of the new branch, the manifold controller determines that the new branch n is a low-resistance branch with a risk of flow interception. When the hydraulic impedance of the cold plate section of the new branch n at the test opening is greater than the preset upper limit of the hydraulic impedance of the cold plate section of the new branch, the manifold controller determines that the new branch n has air bubble retention, cold plate blockage, quick-connect fitting not fully opened, or insufficient pre-filled fluid. When the hydraulic impedance of the cold plate section of the new branch n at the test opening is greater than or equal to the lower limit of the hydraulic impedance of the cold plate section of the new branch and less than or equal to the upper limit of the hydraulic impedance of the cold plate section of the new branch, the manifold controller determines that the new branch n is a branch with normal hydraulic characteristics.

[0080] The criteria for determining the lower and upper limits of the hydraulic impedance of the newly added branch cold plate section are as follows: under the same test opening, valve model, and pipeline conditions as in the testing phase, the hydraulic impedance of the cold plate section calculated for several cold plate assemblies of the same model according to the method described in this step is used as the 5th percentile and the 95th percentile as the upper limit, respectively. The preset lower and upper limits of the hydraulic impedance of the newly added branch cold plate section are determined by statistical analysis of the hydraulic impedance of the cold plate section calculated for several cold plate assemblies of the same model according to the method described in this manual, and the manufacturing tolerance range, under the same test opening, valve model, and pipeline conditions as in the testing phase.

[0081] The manifold controller judges the disturbance coefficient; when the disturbance coefficient is greater than the preset disturbance coefficient threshold, the manifold controller determines that the flow redistribution effect caused by the access of the new branch n on the existing branch exceeds the allowable range, and the incremental step coefficient needs to be reduced in step 400; the preset disturbance coefficient threshold is determined by the engineering ratio between the total allowable flow redistribution of the existing branch during the access of the new branch and the branch flow of the new branch in the trial phase, and is calibrated by hydraulic test under reference working conditions.

[0082] The manifold controller simultaneously calculates the hydraulic identification reliability coefficient of the newly added branch n in the following manner; the purpose of calculating the hydraulic identification reliability coefficient is to comprehensively evaluate the reliability of the hydraulic characteristic data obtained during the trial phase. When the actual flow rate deviates from the expected flow rate, the manifold differential pressure deviates from the reference differential pressure, the actual temperature rise deviates from the expected temperature rise, or the disturbance coefficient is too large during the trial phase, it indicates that the hydraulic identification results during the trial phase are affected by interference factors. The reliability coefficient integrates the above multidimensional deviations into a normalized index, enabling subsequent control links to adaptively adjust the conservatism of the progressive target flow sequence based on this index; first calculate the following four deviation terms; the first The first deviation term is equal to the absolute value of the difference between the branch flow rate of the new branch n during the trial phase and the product of the trial flow rate ratio and the initial target flow rate, minus 1; the second deviation term is equal to the absolute value of the difference between the manifold pressure difference during the trial phase and the manifold reference pressure difference, divided by the absolute value of the difference; the third deviation term is equal to the absolute value of the difference between the inlet and outlet liquid temperature change of the new branch n during the trial phase and the expected temperature rise of the new branch n during the trial phase, divided by the sum of the expected temperature rise of the new branch n during the trial phase and the preset temperature rise correction constant to prevent the denominator from being zero; the fourth deviation term is equal to the disturbance coefficient.

[0083] The expected temperature rise of the newly added branch n during the trial phase is calculated using the following thermal balance method: the expected temperature rise equals the quotient obtained by dividing the power consumption of the server node corresponding to the newly added branch n by a corrected denominator. This corrected denominator is equal to the sum of the product of the preset coolant density, the preset coolant specific heat capacity, and the branch flow rate of the newly added branch n during the trial phase, plus a preset heat capacity flow rate correction constant to prevent the denominator from being zero. The preset heat capacity flow rate correction constant is a positive real number, and its value is much smaller than the minimum heat capacity flow rate obtained by multiplying the preset coolant density, the preset coolant specific heat capacity, and the minimum branch flow rate within the operating range. The effective number of bits in the coolant physical properties, branch flow sensor data, and the numerical stability requirements of the controller's floating-point operations are determined through numerical analysis at the controller implementation level. Its dimension is the same as that of the heat capacity flow rate, and it is only used for denominator correction when the heat capacity flow rate is the dimension. The preset temperature rise correction constant is a positive real number, and its value is much smaller than the lower limit of the allowable coolant temperature rise within the operating range. Its value is determined through numerical analysis at the controller implementation level based on the effective number of bits in the temperature sensor data and the numerical stability requirements of the controller's floating-point operations. Its dimension is the same as that of the coolant temperature rise, and it is only used for denominator correction when the coolant temperature rise is the dimension.

[0084] The hydraulic identification confidence coefficient is equal to 1 divided by a denominator; the denominator is equal to 1 plus the sum of the products of the preset first weight coefficient and the first deviation term, the preset second weight coefficient and the second deviation term, the preset third weight coefficient and the third deviation term, and the preset fourth weight coefficient and the fourth deviation term.

[0085] For example, consider adding a branch road. The branch flow rate during the trial phase is The trial traffic ratio is The initial value of the target flow is During the trial phase, the manifold pressure differential was... The manifold reference pressure difference is New branch roads The temperature change of the inlet and outlet liquids during the trial phase was: New branch roads The expected temperature rise during the exploratory phase is The preset temperature rise correction constant is The disturbance coefficient is The preset first weight coefficient is The preset second weighting coefficient is The preset third weighting coefficient is The preset fourth weighting coefficient is Then the hydraulic identification reliability coefficient Calculate using the following formula: ; ; ; ; ; in, The first deviation term, This is the second deviation term. This is the third deviation term. This is the fourth deviation term. .

[0086] The reason for using this reciprocal form to calculate the reliability coefficient is that when all deviation terms are zero, the denominator equals 1, making the reliability coefficient reach its maximum value of 1. When any deviation term increases, the denominator increases, causing the reliability coefficient to monotonically decrease towards zero. This mathematical form ensures that the reliability coefficient's value strictly falls within the range greater than 0 and not greater than 1, and the mapping relationship between deviation terms and the reliability coefficient has a continuously monotonically decreasing characteristic, facilitating subsequent control links to determine thresholds based on the magnitude of the reliability coefficient. The preset first weight coefficient, preset second weight coefficient, preset third weight coefficient, and preset fourth weight coefficient are all non-negative real numbers, and their sum equals 1. Their specific values ​​within this range are determined by the hydraulic identification results for the initial value deviation of the target flow of the newly added branch, the manifold pressure difference deviation, the temperature rise deviation, and the disturbance coefficient deviation. The sensitivity requirement for the deviation term is determined by calibration through regression analysis of historical data from the trial phase under reference operating conditions. The hydraulic identification reliability coefficient is a real number greater than 0 and not greater than 1, and the closer its value is to 1, the more reliable the hydraulic identification result. When the hydraulic identification reliability coefficient is less than the preset reliability threshold, the manifold controller records the low reliability flag as 1, and in step 400, it reduces the incremental asymptotic coefficient between adjacent control stages by increasing the number of reliability additional stages; otherwise, the low reliability flag is set to 0. The preset reliability threshold is a real number greater than 0 and not greater than 1, and its specific value within this range is determined by the engineering requirements of the hydraulic identification result for the convergence of subsequent progressive self-equalizing flow control, and is calibrated through hydraulic tests under reference operating conditions.

[0087] The manifold controller outputs the combined hydraulic impedance of the newly added branch n under the trial opening, the hydraulic impedance of the valve section, the hydraulic impedance of the cold plate section, the indication flag for a negative difference in the hydraulic impedance of the cold plate section, the disturbance coefficient, the hydraulic identification confidence coefficient, the above discrimination results, the low confidence flag, and the abnormal flow estimation flag of the newly added branch to step 400.

[0088] In an optional embodiment, when the abnormal flag for the newly added branch flow estimation is set, or when the hydraulic identification confidence coefficient is continuously lower than the preset confidence threshold, the manifold controller will revert the opening of the newly added branch valve to the preset minimum controllable valve opening and extend the trial period before re-collecting trial phase data. When the number of consecutive re-trials reaches the preset upper limit of the number of re-trials and still no effective flow rate is obtained in the trial phase of the newly added branch, the manifold controller will stop the gradual target flow adjustment of the newly added branch and output a hydraulic identification failure alarm for the newly added branch to the server management interface. The preset upper limit of the number of re-trials is determined by the longest allowed cooling establishment time and server node online protection time during the newly added branch access process.

[0089] Step 400: For newly added branches, a progressive target flow sequence is generated based on the hydraulic impedance data, disturbance coefficient, and hydraulic identification confidence coefficient of the newly added branches. For expanded branches, a progressive target flow sequence is generated based on the power consumption of the server node, the outlet temperature of the branch, and the inlet temperature of the branch. The controllable actuator is adjusted based on the progressive target flow sequence and the lower limit of the protection flow.

[0090] Based on the combined hydraulic impedance, valve section hydraulic impedance, cold plate section hydraulic impedance, negative cold plate section hydraulic impedance difference flag, disturbance coefficient, hydraulic identification confidence coefficient, low confidence flag, and abnormal flow estimation flag of the new branch n under the trial opening obtained in step 300, as well as the server node power consumption, branch outlet temperature, and branch inlet temperature provided by the server management interface, the manifold controller updates the target flow of the new branch n in the following manner: The manifold controller first calculates the following initial target flow according to the thermal balance caliber. The initial target flow is equal to the quotient obtained by dividing the server node power consumption corresponding to the new branch n by a denominator, which is equal to the product of the preset coolant density, the preset coolant specific heat capacity, and the preset allowable coolant temperature rise. The manifold controller then multiplies the initial target flow by the reciprocal of the preset liquid-cooled capture rate to obtain the engineering-corrected target flow.

[0091] The manifold controller then performs a closed-loop correction based on the deviation between the actual temperature rise (obtained by the difference between the outlet and inlet temperatures of the newly added branch n at the end of the current stage) and the preset allowable coolant temperature rise. Specifically, when the actual temperature rise exceeds the preset allowable coolant temperature rise, the target flow rate after engineering correction is increased by multiplying the preset target flow rate temperature rise correction coefficient by the difference between the actual temperature rise and the preset allowable coolant temperature rise, so that the branch outlet temperature returns to the range corresponding to the preset allowable coolant temperature rise. When the actual temperature rise does not exceed the preset allowable coolant temperature rise, the target flow rate after engineering correction remains unchanged. The value of the preset target flow rate temperature rise correction coefficient is... The sensitivity of the branch flow rate to the actual temperature rise and the target flow rate adjustment margin of the cold plate assembly under reference operating conditions are calibrated and determined through hydraulic tests under reference operating conditions. The final target flow rate is clamped at the upper and lower limits by the preset upper limit of the branch target flow rate and the minimum safe cooling flow rate corresponding to the new branch, respectively, so that the final target flow rate falls within the engineering allowable range defined by the minimum safe cooling flow rate and the preset upper limit of the branch target flow rate. The preset upper limit of the branch target flow rate is determined by the rated flow rate of the cold plate assembly corresponding to the new branch and the maximum allowable flow rate of the liquid cooling branch under reference operating conditions through hydraulic tests under reference operating conditions.

[0092] The manifold controller generates a progressive target flow sequence. This progressive target flow sequence refers to an ordered set of target flows, starting with the flow rate of the newly added branch n during the trial phase and ending with the final target flow rate after thermal balance calculations, engineering corrections, temperature rise closed-loop corrections, and upper and lower limit clamping. The sequence is divided according to the total number of control phases M. The reason for using a progressive target flow sequence instead of a one-step flow setting is that the liquid-cooled manifold has a parallel network structure. Each increase in the flow rate of the newly added branch will cause a change in the manifold differential pressure and lead to a redistribution of the existing branch flow. If the flow rate of the newly added branch is further increased from the trial flow rate to the target flow rate, the sudden change in the manifold differential pressure and the drop in the existing branch flow rate may exceed the protection constraints. The progressive target flow sequence decomposes the total flow increment into multiple control phases for gradual implementation, ensuring that the change in manifold differential pressure in each phase is controlled gradually. The flow drop of existing branches is controlled within the constraints; the progressive target flow sequence includes the total number of control stages M, the number of each control stage m, the asymptotic coefficient corresponding to each control stage, and the target flow of each control stage; let the total number of control stages be M, where stage 0 is the trial stage or the current stable stage before entering progressive control, and the branch flow, manifold differential pressure, and valve opening of stage 0 are respectively used as the previous stage data of stage 1; for each control stage number m, m is a positive integer between 1 and M, the target flow of the new branch n in stage m is calculated as follows: first, calculate the following intermediate quantity, which is equal to the product of the asymptotic coefficient of stage m and the final target flow minus the branch flow of the new branch n in the trial stage; the target flow of the new branch n in stage m is equal to the sum of the branch flow of the new branch n in the trial stage plus the intermediate quantity.

[0093] The asymptotic coefficient of the m-th stage satisfies the following monotonically increasing relationship: the asymptotic coefficient of the first stage is greater than 0; when m is a positive integer between 1 and M minus 1, the asymptotic coefficient of the m-th stage is less than the asymptotic coefficient of the m plus 1-th stage; the asymptotic coefficient of the M-th stage is equal to 1; in this embodiment, the asymptotic coefficient adopts a linear sequence, that is, the asymptotic coefficient of the m-th stage is equal to the quotient obtained by dividing the stage number m by the total number of control stages M; the reason for using a linear sequence as the asymptotic coefficient is that the linear sequence makes the flow increment of each control stage equal, so that the flow redistribution disturbance amplitude caused by each stage to the existing branch is consistent, avoiding the situation where the flow increment of a certain stage is too large and exceeds the protection flow lower limit of the existing branch. At the same time, the computational complexity of the linear sequence is the lowest, which is suitable for the manifold controller to calculate in real time in each control cycle.

[0094] The total number of control stages M is dynamically determined based on the discrimination result of step 300 and the low confidence flag. The total number of control stages M is equal to the sum of the preset basic stage number, the impedance additional stage number, the disturbance additional stage number, and the confidence additional stage number. The reason for adopting the method of dynamically determining the total number of control stages M is that the differences in hydraulic characteristics of different newly added branches result in different degrees of disturbance to the existing branches during their connection process. Branches with low hydraulic impedance have strong flow grabbing ability during valve opening and require more stages to suppress the flow increment in each stage. Branches with large disturbance coefficients indicate that the manifold parallel network is highly sensitive to the connection of this branch and requires a slower transition. Branches with low hydraulic identification confidence indicate that the hydraulic parameters obtained in the trial stage are unreliable and require a more conservative strategy to implement a gradual transition. Dynamically determining the total number of control stages M enables the gradual target flow sequence to adaptively adjust the transition speed according to the actual hydraulic characteristics of each newly added branch.

[0095] The preset base stage number is a positive integer, and its value is determined by the engineering ratio between the number of stages required for the new branch to transition from the branch flow rate in the trial stage to the target flow rate and the total allowable flow redistribution of the existing branch, calibrated through hydraulic tests under reference operating conditions. When the hydraulic impedance of the cold plate section of the new branch n at the trial opening is less than the lower limit of the hydraulic impedance of the cold plate section of the new branch, the impedance additional stage number is taken as the preset impedance additional stage increment, which is used to increase the number of stages to reduce the flow increment of each stage. When the indication flag for the negative hydraulic impedance difference of the cold plate section of the new branch n is set, the impedance additional stage number is also taken as the preset impedance additional stage increment, which is used for a conservative gradual transition under the condition that the hydraulic identification cannot separate the pressure drop of the cold plate section; otherwise, the impedance additional stage number is 0. When the disturbance coefficient is greater than the disturbance coefficient, the impedance additional stage number is 0. When the threshold or the abnormal flag for the newly added branch flow estimation is set, the number of disturbance additional stages is taken as the preset disturbance additional stage increment; otherwise, the number of disturbance additional stages is 0. When the low confidence flag is 1, the number of confidence additional stages is taken as the preset confidence additional stage increment; otherwise, the number of confidence additional stages is 0. The preset impedance additional stage increment, the preset disturbance additional stage increment, and the preset confidence additional stage increment are all positive integers. Their values ​​are determined by the number of gradual transition stages required between the branch flow and the target flow in the low-resistivity branch during the trial phase, the number of gradual transition stages required for the total allowable flow redistribution of the existing branch when the disturbance coefficient is greater than the disturbance coefficient threshold, and the number of additional gradual transition stages required under low confidence conditions for hydraulic identification. These values ​​are determined by calibration through hydraulic tests under reference operating conditions.

[0096] The manifold controller simultaneously generates the following inter-stage constraints, which apply to the new branch n and all existing branches in the existing branch set: For each existing branch in the existing branch set, the branch flow rate in stage m is not less than the lower limit of the protection flow rate of the branch, which is taken from step 200; The absolute value of the difference between the manifold differential pressure in stage m and the manifold differential pressure in stage m minus 1 is not greater than the preset maximum allowable change in manifold differential pressure between stages; For each branch in the branch set composed of the existing branch set and the new branch n, the branch flow rate in stage m and the branch flow rate in stage m minus 1 are... The absolute value of the difference shall not exceed the preset maximum allowable branch flow rate change between stages; the preset maximum allowable manifold pressure difference change between stages is defined as the upper limit of the absolute value of the difference in manifold pressure difference between two adjacent control stages, and its value is determined by the pressure resistance rating of the cold plate assembly, quick connector and liquid-cooled manifold, as well as the transition smoothness requirements of the existing branch flow redistribution, through hydraulic tests under reference operating conditions; the preset maximum allowable branch flow rate change between stages is determined by the cold plate assembly's ability to withstand step disturbances in branch flow rate and the heat dissipation transient margin of the server node, through hydraulic tests under reference operating conditions.

[0097] Within each control phase, the manifold controller, based on the progressive target flow sequence, the lower limit of the protection flow given in step 200, and the current manifold differential pressure, coordinates the bypass valve, the newly added branch valve, the existing branch valve, and the variable frequency pump in the following priority order of action. The reason for adopting the priority order of action for coordinated adjustment is that the three types of controllable actuators—bypass valve, branch valve, and variable frequency pump—have different mechanisms of influence on manifold differential pressure and branch flow and different response times. The bypass valve responds fastest to the manifold differential pressure and does not directly change the opening of each branch valve, making it suitable as the first buffer for differential pressure fluctuations. The adjustment of the opening of the newly added branch valve directly determines the flow acquisition speed of the newly added branch. The protection action of the existing branch ensures the cooling safety of the existing branch. The output adjustment of the variable frequency pump changes the total liquid supply capacity of the manifold. Executing in the above priority order ensures that the actions of each controllable actuator do not conflict with each other and that each performs its most suitable adjustment function.

[0098] The bypass valve fine-tuning is the first priority action; the manifold controller adjusts the bypass valve opening at a preset bypass valve change rate to absorb short-term fluctuations in manifold differential pressure caused by the addition of a new branch, ensuring that the absolute value of the difference between the manifold differential pressure in stage m and stage m-1 is not greater than the maximum allowable change in manifold differential pressure between stages; the preset bypass valve change rate is determined based on the rated stroke time of the bypass valve and the maximum adjustment rate of the bypass valve actuator, according to the dynamic response curve provided by the bypass valve manufacturer; when the manifold differential pressure in stage m is higher than that in stage m-1 and the difference exceeds the maximum allowable change in manifold differential pressure between stages, the bypass valve opening is increased according to the preset bypass valve change rate; when the manifold differential pressure in stage m is lower than that in stage m-1 and the difference exceeds the maximum allowable change in manifold differential pressure between stages, the bypass valve opening is decreased according to the preset bypass valve change rate, and the bypass valve opening is limited between the preset minimum bypass opening and the preset maximum bypass relief opening.

[0099] The adjustment of the valve opening of the newly added branch is the second priority action; the manifold controller updates the valve opening of the newly added branch n in the following manner: the valve opening of the newly added branch n in the m+1 stage is equal to the valve opening of the newly added branch n in the m stage plus a correction amount; the correction amount is equal to the product of the control gain of the newly added branch n and the following difference, which is equal to the target flow rate of the newly added branch n in the m stage minus the branch flow rate of the newly added branch n at the end of the m stage; wherein, the branch flow rate of the newly added branch n at the end of the m stage is taken as the direct measurement value when a branch flow sensor is configured, and is estimated in the following manner when a branch flow sensor is not configured, the estimated branch flow rate is equal to the product of the preset flow coefficient of the newly added branch n, the effective flow function value of the newly added branch n at the corresponding valve opening in the m stage, and the arithmetic square root of the manifold pressure difference in the m stage.

[0100] The control gain of the newly added branch n is tuned as follows to avoid contamination of the control gain by the valve throttling pressure drop under the trial opening, excessive control gain leading to large opening transitions and pressure difference disturbances, and continuous accumulation of control gain when the valve is saturated. The reason for adopting the above three tuning objectives is that when the valve is in the small opening range under the trial opening, the proportion of its throttling pressure drop to the combined pressure drop is high. If the control gain is directly calculated based on the combined hydraulic impedance including the valve throttling pressure drop, the impedance of the cold plate assembly will be overestimated, resulting in an excessively large control gain. An excessively large control gain will cause the valve opening to transition too much within a single control cycle, resulting in sudden changes in manifold pressure difference and a drop in the flow of the existing branch. When the valve opening has reached the maximum opening, if the control gain continues to accumulate, an opening jump will occur when the valve exits saturation. The above three tuning objectives are designed to suppress the above three instability mechanisms.

[0101] The manifold controller first calculates the sensitivity factor of the newly added branch n as follows: The sensitivity factor is equal to the difference between the branch flow rate of the newly added branch n at the end of the most recently completed control phase and the branch flow rate of the newly added branch n at the beginning of the control phase when the change in branch valve opening is positive and non-zero, divided by the sum of the change in branch valve opening of the newly added branch n during the control phase and a preset valve opening correction constant. The preset valve opening correction constant is a positive real number with the same dimensions as the branch valve opening. Its value is much smaller than the minimum positive value of the valve opening change within the operating range. Its value is determined by the effective number of bits in the valve opening detection module data and the floating-point operation of the controller. Numerical stability requirements are determined through numerical analysis at the controller implementation level to avoid excessively small denominators in the sensitivity factor calculation when the branch valve opening change is close to zero. When there is no completed control phase or the branch valve opening change of the newly added branch n is zero in the most recently completed control phase, the sensitivity factor is taken as the product of the preset flow coefficient of the newly added branch n and the derivative of the effective flow function of the newly added branch n at the trial opening with respect to the branch valve opening at the trial opening, multiplied by the arithmetic square root of the manifold reference pressure difference. The branch valve opening change is the difference between the branch valve opening at the end of the control phase and the branch valve opening at the beginning of the control phase.

[0102] For example, consider adding a branch road. The change in branch valve opening during the most recently completed control phase was: ( (Additional branch at the end of this control phase) The branch flow is The newly added branch road at the beginning of the control phase The branch flow is The preset valve opening correction constant is New branch roads The preset flow coefficient is New branch roads Testing the opening The derivative of the effective flow function with respect to the branch valve opening is taken as: The manifold reference pressure difference is Then, a new branch road will be added. Sensitivity factor Calculate using the following formula: When there is a completed control phase and hour: ; When there is no completed control phase or hour: ; Specifically, the derivative of the effective flow function with respect to the branch valve opening is obtained by taking the first derivative of the branch valve opening according to the piecewise definition of the effective flow function described in this specification. Specifically, when the test opening falls within the preset equal percentage adjustable range between the minimum controllable valve opening and the maximum valve opening, the derivative value is equal to the product of the effective flow function value under the equal percentage relationship described in this specification multiplied by the natural logarithm of the valve's adjustable ratio, and then divided by the maximum valve opening. When the test opening falls within the uncontrollable range between the preset valve fully closed judgment opening and the preset minimum controllable valve opening, the derivative value is equal to the difference between the preset equal percentage function value at the minimum controllable valve opening and the preset leakage flow function value at the valve closed state, divided by the difference between the preset minimum controllable valve opening and the preset valve fully closed judgment opening. When the test opening falls within the fully closed range or the fully open saturation range, the derivative value is zero.

[0103] The manifold controller then calculates the control gain as follows: the control gain is equal to the quotient obtained by dividing the preset base gain by a denominator, which is equal to the sum of the sensitivity factor and the preset sensitivity correction constant. The preset sensitivity correction constant is a positive real number with the same dimensions as the sensitivity factor. Its value is much smaller than the minimum positive value of the sensitivity factor within the operating range. Its value is determined through numerical analysis at the controller implementation level, based on the minimum value of the sensitivity factor within the operating range and the numerical stability requirements of the controller's floating-point operations. This is used to avoid controlling the sensitivity factor when it approaches zero. If the control gain is too high, perform upper and lower limit clamping and hydraulic impedance correction as follows to ensure that the control gain is not affected by the valve throttling pressure drop under the trial opening. When the indicator flag indicating that the hydraulic impedance difference of the cold plate section of the newly added branch n is negative is set, the control gain will no longer be corrected by the ratio of the hydraulic impedance of the cold plate section of the newly added branch n under the trial opening to the preset reference hydraulic impedance. Instead, it will be corrected by reducing the preset base gain by the preset low gain protection factor, which is a real number greater than 0 and less than 1. When the indicator flag is not set... When the ratio of the hydraulic impedance of the cold plate section of the newly added branch n at the test opening to the preset reference hydraulic impedance falls within the preset hydraulic impedance correction ratio range, the control gain is multiplied by the ratio of the hydraulic impedance of the cold plate section of the newly added branch n at the test opening to the preset reference hydraulic impedance to obtain the hydraulic impedance-corrected control gain. When this ratio falls outside the preset hydraulic impedance correction ratio range, the ratio is clamped according to the lower or upper limit of the preset hydraulic impedance correction ratio range before further correction. Finally, the control gain is clamped at the lower limit of the preset branch control gain. The manifold controller clamps the branch control gain according to the preset upper limit, ensuring that the control gain value falls within the engineering allowable range defined by the preset lower limit and upper limit of the branch control gain. Simultaneously, the manifold controller performs anti-integral saturation processing on the branch valve opening correction. When the branch valve opening of the newly added branch n reaches its maximum opening in stage m and the change in branch valve opening in stage m is positive, no further positive integral correction is applied to the branch valve opening in stage m, preventing the branch valve opening from continuously accumulating under saturation conditions.

[0104] The preset base gain is determined by the sensitivity of the newly added branch valve opening to the branch flow rate and the constraint of the valve opening change rate, through calibration and testing under reference operating conditions. The preset reference hydraulic impedance is determined by the hydraulic impedance of the cold plate section calculated by the same model of cold plate assembly under reference operating conditions according to the method described in this manual, based on the product specifications provided by the cold plate assembly manufacturer and the hydraulic test data under reference operating conditions. The preset hydraulic impedance correction ratio range is an interval centered at 1, with the upper and lower parts expanded according to the corresponding engineering margins. Its value is determined by the allowable correction range of the control gain to the hydraulic impedance change, through calibration and testing under reference operating conditions. The preset low gain protection factor is determined by the allowable control gain under the condition that the hydraulic identification cannot separate the pressure drop of the cold plate section. The reduction range is determined by calibration through hydraulic tests under reference operating conditions; the preset lower limit and upper limit of branch control gain are determined by the control gain closed-loop stability margin and valve opening change rate constraints, and are calibrated through step response tests under reference operating conditions; when the hydraulic impedance of the cold plate section of the newly added branch n at the trial opening is less than the lower limit of the hydraulic impedance of the cold plate section of the newly added branch, the control gain obtained in the above manner is reduced relative to the reference operating condition to avoid valve jump opening under low resistance conditions; when the indication flag bit of the cold plate section hydraulic impedance difference of the newly added branch n is set, the control gain is reduced and corrected by the preset low gain protection multiple to avoid large opening jumps when the hydraulic identification cannot separate the pressure drop of the cold plate section.

[0105] Existing branch protection is the third priority action; the manifold controller continuously monitors the measured or estimated flow rate of each existing branch; when an existing branch exists such that the difference between the branch flow rate in stage m and the lower limit of the protection flow rate of that branch is less than or equal to the preset protection margin, the manifold controller selects the protection action according to the source of the flow shortage in the existing branch in the following manner to avoid the situation where the pump pressure increase is offset by the bypass short circuit; the reason for selecting different protection actions according to the source of the flow shortage is that the fundamental reason for the flow-grabbing type flow shortage is that the newly added or expanded branch divides the flow under the condition of constant manifold pressure difference. If the flow from an existing branch is diverted, increasing the output of the variable frequency pump will not solve the flow competition problem; instead, it will cause the newly added branch to receive more flow, exacerbating the flow competition. The correct protective action is to limit the further increase of the valve opening of the newly added branch and close the bypass valve to prioritize the supply flow to each liquid-cooled branch. The root cause of differential pressure flow shortage is insufficient manifold supply pressure or excessive bypass flow diversion, which reduces the available differential pressure of each branch. In this case, limiting the valve opening of the newly added branch cannot restore the flow from the existing branch. The correct protective action is to increase the output supply pressure of the variable frequency pump and close the bypass valve to increase the available differential pressure of each branch.

[0106] The preset protection margin is determined by calibration through hydraulic tests under reference operating conditions, based on the measurement accuracy of the branch flow sensor and the allowable engineering fluctuation range of the existing branch near the lower limit of the protection flow. The manifold controller first determines the source of flow shortage in the existing branch in the following manner: when the absolute value of the difference between the current manifold differential pressure and the manifold reference differential pressure does not exceed the manifold differential pressure change judgment threshold, and the absolute value of the difference between the current bypass flow measured by the bypass flow sensor and the reference bypass flow does not exceed the preset bypass flow change judgment threshold, the controller determines... The source of flow shortage in existing branches is the addition of new branches or expansion of existing branches, which is called flow-grabbing type flow shortage. When the difference between the current manifold differential pressure and the manifold reference differential pressure is negative and its absolute value exceeds the manifold differential pressure change judgment threshold, or when the difference between the current bypass flow measured by the bypass flow sensor and the reference bypass flow is positive and its value exceeds the preset bypass flow change judgment threshold, the source of flow shortage in existing branches is determined to be insufficient manifold differential pressure or excessive bypass flow diversion, which is called differential pressure type flow shortage. When the above two conditions occur simultaneously, differential pressure type flow shortage is the main problem.

[0107] When a flow shortage is detected as a rushing flow, the manifold controller performs the following actions: it restricts the change in the branch valve opening of the new branch n in the m+1 stage, making it equal to the branch valve opening of the new branch n in the m stage, that is, it stops increasing the branch valve opening of the new branch n and waits until the branch flow of the existing branch recovers to more than the sum of the lower limit of the protection flow of the existing branch and the preset protection margin; during this waiting period, the manifold controller simultaneously closes the bypass valve to the preset minimum bypass opening, so that the liquid supply flow is preferentially supplied to each liquid cooling branch and is not bypassed and short-circuited.

[0108] When a differential pressure-type flow shortage is detected, the manifold controller performs the following action: increasing the output liquid supply pressure of the variable frequency pump. Specifically, the manifold controller calculates the increase in the variable frequency pump's liquid supply pressure as follows: this increase is equal to the product of a preset pump pressure compensation gain and the following difference: this difference is equal to the difference between the lower limit of the protection flow rate of the branch that triggered protection in the existing branch set and the branch flow rate of that branch in stage m. When multiple branches in the existing branch set trigger protection simultaneously, the maximum value of the above differences is taken as the calculation input. The preset pump pressure compensation gain is constrained by the sensitivity of the variable frequency pump's liquid supply pressure to the branch flow rate and the rate of change of the manifold differential pressure, and is determined by referring to the operating conditions. The step response test is used for calibration and determination; the manifold controller adds the current variable frequency pump supply pressure command value to the increase amount as the new variable frequency pump supply pressure command value, and applies a rate constraint on the increase amount according to the maximum manifold differential pressure change rate, so that the absolute value of the change in the variable frequency pump supply pressure command value between two adjacent control cycles is not greater than the product of the maximum manifold differential pressure change rate and the length of the control cycle; the new manifold differential pressure command value is equal to the difference between the new variable frequency pump supply pressure command value and the return pressure; while increasing the pump output, the manifold controller closes the bypass valve to the preset minimum bypass opening, so that the increase in variable frequency pump supply pressure is not canceled by the bypass short circuit.

[0109] The preset threshold for judging the change in bypass flow rate is determined by statistical analysis of the historical sensor data continuously collected during system operation, based on the measurement noise level of the bypass flow sensor and the allowable fluctuation range of the reference bypass flow rate during operation. The preset minimum bypass opening is a real number that is greater than zero and not less than the minimum controllable opening specified by the bypass valve manufacturer. Its value is determined by calibration of the minimum controllable opening of the bypass valve and the minimum circulating flow required by the bypass pipeline during operation, based on hydraulic tests under reference operating conditions.

[0110] Differential pressure change suppression is the fourth priority action; when the absolute value of the difference between the manifold differential pressure in stage m and stage m minus 1 is greater than the maximum allowable manifold differential pressure change between stages, the manifold controller sets the branch valve opening change command of the newly added branch n in stage m plus 1 to zero, that is, makes the branch valve opening of the newly added branch n in stage m plus 1 equal to the branch valve opening in stage m, and simultaneously adjusts the bypass valve opening to restore the manifold differential pressure change to the range limited by the maximum allowable manifold differential pressure change between stages, and waits for the system to stabilize.

[0111] The manifold controller outputs the valve opening command, bypass valve opening command, and variable frequency pump liquid supply pressure command for each branch in the current stage to the controllable actuator, and uses the measured response data of the current stage for stability determination; the measured response data includes the branch flow of each existing branch in the current stage, the manifold differential pressure in the current stage, and the branch flow of the newly added branch n in the current stage.

[0112] After each control phase, the manifold controller determines whether the liquid-cooled manifold has reached a stable state based on the measured response data. The purpose of the stability determination after each control phase is to ensure that the flow distribution in the current phase has reached a steady-state equilibrium before entering the next phase, so as to avoid the accumulation and amplification of transient disturbances caused by the superposition of the flow increment in the next phase before the hydraulic transient process in the previous phase has decayed.

[0113] A stage of stable state requires the simultaneous fulfillment of the following three conditions, and the duration of these three conditions being simultaneously met is not less than the duration corresponding to the system stability judgment time window. The reason for using the simultaneous fulfillment of these three conditions and a duration not less than the system stability judgment time window as the stage stability judgment criterion is that the first condition ensures that the flow rate of the newly added branch has converged to the target value, thus achieving the control objective; the second condition ensures that the flow rates of all existing branches are strictly higher than the lower limit of the protection flow rate, thus ensuring cooling safety; and the third condition ensures that the manifold pressure difference has stopped changing, thus completely attenuating the hydraulic transient process. All three conditions are indispensable and must be met continuously for a certain duration to eliminate instantaneous misjudgments caused by sensor noise. The first condition is the convergence condition for the flow rate of the newly added branch: the absolute value of the difference between the branch flow rate of the newly added branch n at the end of stage m and the target flow rate of the newly added branch n in stage m is less than the preset flow convergence error threshold; the second condition… The first condition is the protection condition for existing branches. Among all existing branches in the set of existing branches, the minimum value of the difference between the branch flow rate in stage m and the lower limit of the protection flow rate of the branch is greater than 0, that is, the branch flow rate of all existing branches in this stage is strictly greater than their respective lower limits of protection flow rate. The second condition is the convergence condition of the manifold differential pressure change rate. The absolute value of the derivative of the manifold differential pressure with respect to time is less than the preset manifold differential pressure change rate convergence threshold. The preset flow convergence error threshold is determined by the measurement accuracy of the branch flow sensor and the engineering allowable deviation of the target flow rate of the new branch, and is calibrated through hydraulic tests under reference operating conditions. The preset manifold differential pressure change rate convergence threshold is determined by the measurement noise level of the supply pressure sensor and the return pressure sensor and the allowable fluctuation range of the manifold differential pressure during operation, and is determined by statistical analysis of the historical sensor data continuously collected by the system during operation.

[0114] When all three conditions above are met, the manifold controller determines that the m-th stage is stable and enters the m+1-th stage; when m equals the total number of control stages M and the M-th stage is stable, the newly added branch n reaches the target flow rate and enters step 500.

[0115] If any of the above three conditions is not met, the manifold controller will perform a corrective action according to the following rules: When the absolute value of the difference between the branch flow rate of the new branch n at the end of stage m and the target flow rate of the new branch n in stage m is not less than the flow convergence error threshold, and the branch flow rate of the new branch n at the end of stage m is greater than the target flow rate of the new branch n in stage m, it is considered a flow overshoot. The manifold controller will reduce the opening of the branch valve of the new branch n and adjust it in the following way: The manifold controller first calculates the flow overshoot, which is equal to the difference between the branch flow rate of the new branch n at the end of stage m and the target flow rate of the new branch n in stage m; the manifold controller... The device then calculates a preset correction step size, which is equal to the quotient obtained by dividing the flow overshoot by the sum of the sensitivity factor of the newly added branch n and the preset sensitivity correction constant, and then multiplying it by the preset overshoot backoff ratio. The preset overshoot backoff ratio is a real number greater than 0 and not greater than 1, and its value is determined by the allowable single-step opening backoff amplitude and valve opening change rate under the flow overshoot condition, and is calibrated through a step response test under the reference working condition. The branch valve opening of the newly added branch n in the m+1 stage is equal to the branch valve opening of the newly added branch n in the m stage minus the preset correction step size, and is clamped at the lower limit according to the preset minimum controllable valve opening.

[0116] When an existing branch causes its flow rate in stage m to be less than or equal to the lower limit of its protection flow rate, the manifold controller selects a protection action according to the branch discrimination criteria for flow-grabbing and differential pressure flow shortages described in the third priority action above. Specifically, when a flow-grabbing flow shortage is determined, the valve opening of the newly added branch n in stage m+1 is restricted, and the bypass valve is closed to the preset minimum bypass opening. When a differential pressure flow shortage is determined, the variable frequency pump output supply pressure is increased according to the calculation method for the variable frequency pump supply pressure increase described in the third priority action above, and the bypass valve is closed to the preset minimum bypass opening. The action of increasing the variable frequency pump output supply pressure while simultaneously opening the bypass valve to the pressure relief opening is no longer used. To prevent the increase in supply pressure from being offset by a bypass short circuit; when the absolute value of the derivative of the manifold differential pressure with respect to time is not less than the convergence threshold of the manifold differential pressure change rate, the manifold controller keeps the branch valve opening of the newly added branch n unchanged and extends the stabilization waiting time to twice the system stability determination time window; when the above correction actions still fail to meet the stage stability condition and the duration reaches three times the system stability determination time window, the manifold controller returns to step 300, re-executes the low-disturbance trial supply and combined hydraulic characteristic estimation, and regenerates the progressive target flow sequence based on the updated combined hydraulic impedance, valve section hydraulic impedance, cold plate section hydraulic impedance, disturbance coefficient, and hydraulic identification confidence coefficient.

[0117] The manifold controller records the stage stability flag, the actual next stage number entered, and correction actions, which are used for operation logs and fault tracing.

[0118] When the event identified in step 200 is branch thermal load expansion, the manifold controller performs target flow redistribution on the expanded branch in the following manner, instead of performing the low-disturbance trial liquid supply step for the new branch in step 300. This is because the expanded branch is a branch in the existing branch set that is already in online operation, its cold plate assembly has been pre-filled with liquid, and its hydraulic characteristics have been established as a baseline in step 100. There is no need to re-identify the hydraulic characteristics; it is only necessary to recalculate the target flow based on the power consumption of the added server node and gradually adjust it to the new target flow. The manifold controller first uses the same heat balance calculation method as the target flow update for the new branch to adjust the current server flow of the expanded branch. The target flow rate of the expansion branch is recalculated using the node power consumption, the actual temperature rise obtained by the difference between the current branch outlet temperature and the branch inlet temperature, and the current target heat dissipation level as inputs. Specifically, the initial target flow rate is equal to the quotient obtained by dividing the current server node power consumption of the expansion branch by the product of the preset coolant density, the preset coolant specific heat capacity, and the preset allowable coolant temperature rise, and then multiplying it by the reciprocal of the preset liquid cooling capture rate to obtain the engineering-corrected target flow rate. Then, a closed-loop correction is performed based on the deviation between the actual temperature rise and the preset allowable coolant temperature rise. Finally, the upper limit clamp and lower limit clamp are performed according to the preset upper limit of the branch target flow rate and the minimum safe cooling flow rate, respectively, to obtain the target flow rate of the expansion branch.

[0119] The manifold controller determines the total number of control stages M for the progressive target flow sequence under a branch thermal load expansion event in the following manner: Since the expansion branch is a branch in the existing branch set that is already in online operation, its hydraulic characteristics have been established as a baseline in step 100. There is no abnormal flag for the cold plate section hydraulic impedance judgment result and the new branch flow estimation in step 300. Therefore, the method for determining the total number of control stages M differs from that for a new branch access event. The manifold controller first calculates the absolute value of the difference between the target flow of the expansion branch and the current branch flow, and records this absolute value as the expansion flow increment. The manifold controller then divides the expansion flow increment by the maximum allowable branch flow change between stages and rounds the quotient upwards. This rounded result is recorded as the flow constraint stage number. Simultaneously, the manifold controller calculates the absolute value of the difference between the target valve opening corresponding to the target flow of the expansion branch and the current branch valve opening, and divides this absolute value by the maximum valve opening. The quotient of the product of the rate of change and the system stability determination time window is rounded up, and this rounded result is recorded as the number of opening constraint stages. The manifold controller takes the maximum value between the number of flow constraint stages and the number of opening constraint stages, and this maximum value is recorded as the number of constraint derived stages. The manifold controller then takes the maximum value between the number of constraint derived stages and the preset basic stage number, and this maximum value is used as the total number M of control stages for the progressive target flow sequence under the branch thermal load expansion event. The above determination method ensures that the total number of control stages M simultaneously satisfies the constraint of the maximum allowable branch flow change between stages and the constraint of the maximum valve opening rate of change, and is not less than the minimum progressive transition stage number specified by the preset basic stage number. The target valve opening of the expanded branch is obtained by dividing the target flow by the product of the preset flow coefficient of the expanded branch and the arithmetic square root of the current manifold pressure difference to obtain the effective flow function target value, and then substituting it into the inverse function of the effective flow function, and clamping it according to the preset minimum controllable valve opening and the maximum valve opening.

[0120] The manifold controller then takes the difference between the current flow rate of the expansion branch and the target flow rate of the expansion branch as input, and adjusts the branch valve opening, bypass valve opening, and variable frequency pump supply pressure of the expansion branch gradually according to the progressive target flow rate sequence, inter-stage constraints, pump-valve coordinated control priority action sequence, and stability judgment conditions described above in this step. This allows the branch flow rate of the expansion branch to gradually transition to the target flow rate of the expansion branch. During this progressive adjustment process, the manifold controller simultaneously protects the flow rate of all existing branches in the set of existing branches except for the expansion branch according to the existing branch protection flow lower limit and inter-stage constraints described above in this step. This ensures that the branch flow rate of the aforementioned existing branches does not fall below their respective protection flow lower limits during the expansion process.

[0121] When the expanded branch reaches its target flow rate and meets the stability judgment condition, the manifold controller enters the manifold hydraulic fingerprint update process in step 500. If, during the expansion process, the chip temperature corresponding to the expanded branch continuously exceeds the preset chip temperature expansion threshold and the duration exceeds three times the system stability judgment time window, the manifold controller sends a load reduction request to the server management interface. This load reduction request includes the expanded branch number, the current chip temperature, and a command to roll back the target heat dissipation level by one level. The server management interface reduces the power consumption of the corresponding server node or adjusts the target heat dissipation level based on this load reduction request, and recalculates the target flow rate in the above manner until the chip temperature corresponding to the expanded branch returns to the preset chip temperature expansion threshold. Within the range; where, the meaning of "target heat dissipation level down by one level" is that the server management interface pre-arranges the target heat dissipation levels into an ordered sequence according to the upper limit of coolant temperature rise from small to large. Downgrading by one level means that the level corresponding to the current target heat dissipation level in the ordered sequence is increased by 1, and the level corresponding to the current target heat dissipation level is used as the downgraded target heat dissipation level. This makes the preset allowable coolant temperature rise corresponding to the downgraded target heat dissipation level greater than the preset allowable coolant temperature rise before downgrading, thereby making the target flow of the expansion branch less than the target flow before downgrading. When the current target heat dissipation level is already the last level in the ordered sequence, the manifold controller maintains the current target heat dissipation level and does not downgrade, and reports a chip temperature over-limit alarm to the server management interface.

[0122] Step 500: For removed branches, calculate the flow percentage based on baseline operating data, determine whether to enter the slow release mode based on the flow percentage, and reallocate the target flow to the remaining branches; update the manifold hydraulic fingerprint after the branch topology change event ends.

[0123] When the topology change event identified in step 200 is the removal of an existing branch, the manifold controller processes it according to the following procedure.

[0124] The manifold controller first calculates the flow percentage of the removed branch k before removal in the following manner: the flow percentage is equal to the base flow of the removed branch k divided by a correction denominator, which is equal to the sum of the base manifold branch total flow and a preset branch flow correction constant. The base manifold branch total flow is equal to the base manifold total flow minus the base bypass flow. The purpose of calculating the flow percentage of the removed branch is to quantify the contribution of the removed branch to the total manifold flow before removal. This percentage directly determines the disturbance magnitude of the removal event on the manifold differential pressure and the remaining branch flow distribution. The larger the flow percentage, the stronger the impact of the removal event on the manifold hydraulic balance, and the more necessary it is to activate the slow release mode to absorb the impact gradually. The base flow of the removed branch k and the base manifold total flow are taken from the manifold hydraulic fingerprint saved in step 100.

[0125] When the flow rate of the removed branch k before removal exceeds the preset threshold for the flow rate of the removed branch, the manifold controller enters the slow release mode. The reason for entering the slow release mode is that when the flow rate of the removed branch exceeds the threshold, the flow rate it originally carried will be instantly absorbed by the increase in manifold pressure difference after the branch is closed. The sudden increase in manifold pressure difference may exceed the pressure resistance of the cold plate assembly and quick connector. At the same time, the flow rate of the remaining branches may increase due to the increase in manifold pressure difference, which may exceed the rated flow rate of the cold plate assembly. The slow release mode controls the rate of change of manifold pressure difference within a safe range through the coordinated actions of bypass valve pressure relief, bypass valve pressure holding, and variable frequency pump pressure increase or decrease.

[0126] In the slow-release mode, the manifold controller clearly distinguishes between two operating conditions: manifold pressure rise and pressure relief, and pressure maintenance due to flow shortage in the remaining branches, to avoid conflicts between the bypass valve's operating direction and the pressure maintenance requirements of the remaining branches. When the difference between the current manifold differential pressure and the manifold reference differential pressure is positive and its absolute value exceeds the manifold differential pressure change judgment threshold, it is determined that the manifold differential pressure is rising. The manifold controller opens the bypass valve at the rate constraint of the maximum manifold differential pressure change rate, so that the manifold pressure rise caused by removing the closed branch k is absorbed by the bypass pipeline. During this pressure relief process, the upper limit of the bypass valve opening is clamped according to the preset maximum bypass pressure relief opening. The value of the preset maximum bypass pressure relief opening is determined by the maximum allowable value of the bypass valve. The engineering ratio between the opening degree and the minimum liquid supply flow required for the protection of existing branches is determined by calibration through hydraulic tests under reference operating conditions. When the difference between the current manifold differential pressure and the manifold reference differential pressure is non-positive, or when the difference between the flow rate of a branch in the remaining branch set and the lower limit of the protection flow rate of that branch is less than or equal to the preset protection margin, it is determined that the remaining branch is short of flow. The manifold controller closes the bypass valve to the preset minimum bypass opening degree with the rate constraint of the maximum manifold differential pressure change, and adjusts the output of the variable frequency pump according to the rate constraint, so that the liquid supply flow is preferentially supplied to each branch in the remaining branch set. During the pressure holding process of the remaining branch, the manifold controller no longer opens the bypass valve to perform pressure relief.

[0127] When the above two operating conditions occur simultaneously, the main problem is the flow shortage in the remaining branches, and the bypass valve is closed to the preset minimum bypass opening. The preset threshold for the proportion of flow removed from the branches is a real number greater than 0 and less than 1. The specific value within this range is determined by the relationship between the disturbance of the removed branches to the total flow of the manifold and the engineering margin of the cooling capacity of the remaining branches, and is calibrated through hydraulic tests under reference operating conditions.

[0128] The manifold controller determines the remaining branch set as the set of all branches in the existing branch set except for the removed branch k.

[0129] The manifold controller calculates the total cooling flow requirement of the remaining servers based on the power consumption and allowable coolant temperature rise of the server node corresponding to each branch in the remaining branch set, as follows: First, it calculates the single-branch cooling flow requirement for each branch in the remaining branch set. The single-branch cooling flow requirement is equal to the power consumption of the server node corresponding to that branch divided by a denominator. This denominator is equal to the product of the preset coolant density, the preset coolant specific heat capacity, and the preset allowable coolant temperature rise, and then multiplied by the product of the reciprocal of the preset liquid cooling capture rate, so that the single-branch cooling flow requirement reflects the actual heat dissipation undertaken by the liquid cooling circuit. Then, it sums up the single-branch cooling flow requirements of all branches in the remaining branch set, and the summation result is the total cooling flow requirement of the remaining servers.

[0130] The manifold controller then adjusts the variable frequency pump output according to the rate of change constraint, so that the total manifold flow gradually transitions to the flow required by the remaining branch set. Specifically, the manifold controller calculates the target total manifold flow required by the remaining branch set in the following way: the target total manifold flow is equal to the sum of the total cooling demand flow of the remaining servers and the current bypass flow measured by the bypass flow sensor. The manifold controller takes the difference between the target total manifold flow and the current total manifold flow as input, and adjusts the variable frequency pump supply pressure command value by increasing or decreasing it cycle by cycle according to the maximum manifold pressure difference change rate, so that the absolute value of the change in the variable frequency pump supply pressure command value between two adjacent control cycles is not greater than the product of the maximum manifold pressure difference change rate and the length of the control cycle, until the total manifold flow reaches the target total manifold flow.

[0131] The manifold controller redistributes the target flow of each branch in the remaining branch set according to the server power consumption weight. For each branch in the remaining branch set, the target flow of the branch is equal to the product of the following power consumption weight and the total cooling demand flow of the remaining servers. The power consumption weight is equal to the quotient obtained by dividing the power consumption of the server node corresponding to the branch by the sum of the power consumption of the server nodes corresponding to all branches in the remaining branch set. The reason for using the server power consumption weight for flow redistribution is that the heat dissipation demand of the server node is proportional to its power consumption. The server node with high power consumption needs more coolant flow to keep the chip temperature within the allowable range. Distributing the flow according to the power consumption weight ensures that the coolant flow obtained by each branch matches the actual heat dissipation demand of its corresponding server node, avoiding an unbalanced flow distribution state where high-power nodes are undercooled or low-power nodes are overcooled.

[0132] The manifold controller also applies the inter-stage constraints and pump-valve coordinated control priority action sequence in step 400 to each branch in the remaining branch set, transitioning each branch in the remaining branch set from its current branch flow to its respective target flow, and confirming the stability of each transition stage according to the stability determination conditions in step 400.

[0133] When the proportion of traffic in the removed branch k before removal is less than or equal to the threshold of the proportion of traffic in the removed branch, the manifold controller skips the release mode and directly performs the redistribution of the target traffic of each branch in the remaining branch set.

[0134] The manifold controller records the updated set of remaining branches, the target flow of each branch in the set, and the release mode flag for use in operation log recording and subsequent control strategy selection. In this embodiment, the end of a branch topology change event means that the target flow adjustment corresponding to the addition, removal, or expansion of a branch is completed, and the corresponding branch set simultaneously meets the target flow convergence condition, the existing branch protection condition, and the manifold differential pressure change rate convergence condition within the system stability determination time window. The target flow convergence condition is that the absolute value of the difference between the current branch flow and the corresponding target flow of the target branch is less than a preset flow convergence error threshold. The existing branch protection condition is that the current branch flow of each existing branch is greater than the corresponding protection flow lower limit. The manifold differential pressure change rate convergence condition is that the absolute value of the derivative of the manifold differential pressure with respect to time is less than a preset manifold differential pressure change rate convergence threshold.

[0135] When step 400 confirms that the newly added branch n reaches the target flow and stabilizes in stage M, or when the branch removal process confirms that the remaining branch set is stable under the newly allocated target flow, or when the expansion branch meets the stability judgment condition under the target flow of the expansion branch, the manifold controller updates the current branch set of the manifold.

[0136] For a new access event, the updated current branch set is equal to the union of the existing branch set and the newly added branch n; for a branch removal event, the updated current branch set is equal to the set of remaining branches in the existing branch set excluding the removed branch k; for a branch thermal load expansion event, the updated current branch set remains the same as the existing branch set, but the baseline server power consumption, baseline branch inlet temperature, baseline branch outlet temperature, baseline temperature rise, and baseline valve opening corresponding to the expanded branch are all updated according to the baseline operating data after the event ends.

[0137] After the event ends, the manifold controller re-determines the steady-state time according to the steady-state determination conditions described in step 100, and collects the baseline operating data after the event ends. The baseline operating data after the branch topology change event includes the baseline valve opening of each branch after the event ends, the baseline flow rate of each branch after the event ends, the baseline manifold differential pressure after the event ends, the baseline total manifold flow rate after the event ends, and the baseline bypass flow rate after the event ends.

[0138] The manifold controller updates the combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance of each branch in the current branch set at the reference valve opening after the event, as follows: If the reference valve opening after the event is consistent with the reference valve opening before the update, or is converted to the same equivalent valve opening through an effective flow function, then the combined hydraulic impedance is weighted and fused; otherwise, only the hydraulic impedance of the cold plate section is weighted and fused, and the valve section hydraulic impedance and combined hydraulic impedance are recalculated based on the reference valve opening after the event. The updated combined hydraulic impedance is equal to the product of the preset historical weighting coefficient and the combined hydraulic impedance before the update, plus 1 minus the preset historical weighting coefficient, and the difference between the product and the reference valve opening after the event. The product of the combined hydraulic impedances obtained by recalculating the running data; the reason for using preset historical weighting coefficients to weight and fuse the combined hydraulic impedances before the update and the newly calculated combined hydraulic impedances is that the baseline running data after a single topology change event may have random errors due to sensor measurement noise and short-term operating condition fluctuations. If the combined hydraulic impedances before the update are completely replaced by the newly calculated combined hydraulic impedances, the hydraulic model will be overly sensitive to single measurement noise. The weighted fusion method uses the cumulative statistical effect of historical hydraulic impedances to smooth single measurement noise, so that the updated combined hydraulic impedances can track the real change trend of the hydraulic characteristics of the cold plate assembly while suppressing model jitter caused by measurement noise.

[0139] The preset historical weighting coefficient is a real number greater than 0 and less than 1. Its specific value within this range is determined by the engineering weighting relationship between the historical hydraulic impedance and the newly calculated hydraulic impedance during the hydraulic model update process. This relationship is calibrated by performing regression analysis on the baseline operating data before and after several topology change events under the reference operating conditions. For existing branches, the combined hydraulic impedance before the update is taken from the combined hydraulic impedance of the branch at the baseline valve opening saved in step 100. For new branches, the combined hydraulic impedance before the update is taken from the combined hydraulic impedance of the new branch n at the trial opening obtained in step 300. The combined hydraulic impedance recalculated based on the baseline operating data after the event is calculated as follows: the combined hydraulic impedance is equal to the manifold baseline pressure difference after the event divided by a correction denominator, which is equal to the sum of the square of the baseline flow rate of the branch after the event and the flow rate square correction constant.

[0140] The manifold controller simultaneously updates the hydraulic impedance of the valve section of the branch at the reference valve opening after the event in the following manner: the updated hydraulic impedance of the valve section is equal to the quotient obtained by dividing a numerator by a denominator, where the numerator is equal to 1, and the denominator is equal to the sum of the square of the product of the preset flow coefficient of the branch and the effective flow function value of the branch at the reference valve opening after the event, and the preset flow capacity square correction constant; the manifold controller simultaneously updates the hydraulic impedance of the cold plate section of the branch under the reference operating condition after the event in the following manner: the updated hydraulic impedance of the cold plate section is equal to the difference obtained by subtracting the updated valve section hydraulic impedance from the updated combined hydraulic impedance; when the above difference is negative, it is set to zero and the negative difference is recorded as a warning flag.

[0141] The manifold controller uses the following updated state variables as the reference state for the next branch access, removal, or expansion event: updating the existing branch set to the current branch set; updating the reference manifold total flow rate to the reference manifold total flow rate after the event ends; updating the reference bypass flow rate to the reference bypass flow rate after the event ends; updating the manifold reference differential pressure to the manifold reference differential pressure after the event ends; for each branch in the current branch set, updating the branch's reference flow rate to the reference flow rate after the event ends; updating the branch's reference valve opening to the reference valve opening after the event ends; and updating the branch's combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance at the reference valve opening to the updated combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance, respectively.

[0142] The manifold controller exits the branch topology change processing flow and returns to the normal liquid-cooled manifold self-flow sharing control state. It continues to monitor the next branch topology change event according to the judgment conditions in step 200. The purpose of returning to the normal liquid-cooled manifold self-flow sharing control state and continuing to monitor is that multiple branch topology change events may occur continuously during the operation of the data center. After each event, the manifold controller needs to continue monitoring based on the updated manifold hydraulic fingerprint, so that the control system can respond in a timely manner to the next topology change event that occurs at any time, and realize the continuous adaptive flow sharing control of the liquid-cooled manifold.

[0143] Through the coordinated execution of steps 100 to 500 above, the method described in this embodiment can automatically identify the impact of adding, removing, or expanding branches on the manifold flow distribution without interrupting the existing server cooling when the number of parallel branches and the hydraulic impedance of the liquid-cooled manifold change abruptly due to the online access, removal, or expansion of server nodes. It coordinates the control of the variable frequency pump, each branch valve, and the bypass valve according to the protected progressive self-equalization target. Under the constraints of ensuring that the branch flow of each existing branch is not lower than the lower limit of the protected flow of that branch, the change in manifold pressure difference between adjacent control stages does not exceed the maximum allowable change in manifold pressure difference between stages, and the change in the flow of each branch between adjacent control stages does not exceed the maximum allowable change in the flow of each branch between stages, the newly added or expanded branches gradually reach the target flow, and the manifold hydraulic fingerprint is updated after the event ends.

[0144] The embodiments of this application have been described above, but these embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments based on the guidance of these embodiments, and all of them are within the protection scope of these embodiments.

Claims

1. A method for self-flow sharing control of a liquid-cooled manifold for a data center, the method comprising: include: At steady state, baseline operating data is collected, hydraulic impedance data is calculated based on the baseline operating data, and a manifold hydraulic fingerprint is established based on the baseline operating data and the hydraulic impedance data. The system monitors the discriminant parameters of each branch, determines whether a branch topology change event has occurred based on the discriminant parameters, and identifies the corresponding target branch as a newly added branch, a removed branch, or an expanded branch based on the event type of the branch topology change event. It also calculates the lower limit of the protection flow rate based on the manifold hydraulic fingerprint and applies rate-of-change constraints to controllable actuators, including: A branch topology change event is determined to have occurred when the discriminant meets one of the preset explicit criteria or a preset implicit criteria; the determination methods for implicit criteria include: Based on the current total manifold flow, the bypass flow directly measured by the bypass flow sensor, and the baseline total manifold flow and baseline bypass flow in the baseline operating data, calculate the residual total flow of the manifold branch; Calculate the difference between the current manifold differential pressure and the manifold reference differential pressure to obtain the manifold differential pressure residual. For each existing branch, the predicted change in total flow rate of the manifold branch is calculated based on the effective flow function values ​​under the current valve opening and the reference valve opening, the current manifold differential pressure and the reference manifold differential pressure. When the absolute value of the difference between the residual of the total flow of the manifold branch and the predicted change of the total flow of the manifold branch is greater than the preset threshold for judging the change of the total flow of the manifold, or when the absolute value of the residual of the manifold differential pressure is greater than the preset threshold for judging the change of the manifold differential pressure, the implicit judgment condition is satisfied. When a branch topology change event occurs, for each existing branch, the lower limit of the protection flow rate is calculated based on the baseline flow rate and the preset minimum safe cooling flow rate. The rate of change constraint includes the manifold differential pressure change rate constraint and the valve opening change rate constraint. The manifold differential pressure change rate constraint includes that the absolute value of the derivative of the manifold differential pressure with respect to time is not greater than the preset maximum manifold differential pressure change rate. The valve opening change rate constraint includes that the absolute value of the derivative of the branch valve opening with respect to time is not greater than the preset maximum valve opening change rate. Based on the rate of change constraint, a trial liquid supply is performed on the newly added branch. The hydraulic impedance data of the newly added branch is calculated under the trial liquid supply, and the disturbance coefficient and hydraulic identification confidence coefficient are calculated. For newly added branches, a progressive target flow sequence is generated based on the hydraulic impedance data, disturbance coefficient, and hydraulic identification reliability coefficient of the newly added branches. For expanded branches, a progressive target flow sequence is generated based on the server node power consumption, branch outlet temperature, and branch inlet temperature. The controllable actuator is adjusted based on the progressive target flow sequence and the lower limit of the protection flow. For branch removal, the flow percentage is calculated based on baseline operating data, and the flow percentage is used to determine whether to enter the slow release mode and reallocate the target flow to the remaining branches; the manifold hydraulic fingerprint is updated after the branch topology change event ends.

2. The data center liquid-cooled manifold self-flow equalization control method according to claim 1, characterized in that, Methods for establishing manifold hydraulic fingerprints include: When the changes in the connection status of all branches, the valve opening of each branch, the total flow rate of the manifold, and the manifold differential pressure within the preset system stability determination time window do not exceed the corresponding preset steady-state threshold, it is determined to be a steady-state moment, and the current online branch set is recorded as the existing branch set; where the manifold differential pressure is the difference between the supply pressure and the return pressure. Obtain the baseline operating data of each existing branch, and calculate the hydraulic impedance data based on the baseline operating data; The existing branch set, baseline operating data, and hydraulic impedance data are combined to form a manifold hydraulic fingerprint.

3. The data center liquid-cooled manifold self-flow equalization control method according to claim 2, characterized in that, Methods for calculating hydraulic impedance data include: The hydraulic impedance data includes combined hydraulic impedance, valve section hydraulic impedance, and cold plate section hydraulic impedance; The combined hydraulic impedance is the quotient obtained by dividing the manifold reference pressure difference in the reference operating data by the correction denominator, which is the sum of the square of the branch reference flow rate in the reference operating data and the preset flow rate square correction constant. The hydraulic impedance of the valve section is equal to the quotient obtained by dividing 1 by the denominator, where the denominator is the sum of the square of the product of the branch's preset flow coefficient and the effective flow function value, and the preset square correction constant for the flow capacity; the effective flow function is obtained by segmenting the intervals in which the branch valve opening is located. The hydraulic impedance of the cold plate section is equal to the difference between the combined hydraulic impedance and the valve section hydraulic impedance.

4. The data center liquid-cooled manifold self-flow equalization control method according to claim 1, characterized in that, Methods for calculating the hydraulic impedance data of newly added branches include: Based on the server node power consumption, estimate the initial target traffic value of the newly added branch, and determine the trial opening degree based on the preset trial traffic ratio and the initial target traffic value. Under the constraint of valve opening change rate, the valve opening of the newly added branch is increased to the test opening and the preset test time is maintained, and data is collected during the test phase. Based on the data from the trial phase, the combined hydraulic impedance and valve section hydraulic impedance of the newly added branch under the trial opening were calculated respectively. Based on the combined hydraulic impedance and valve section hydraulic impedance under the trial opening, the hydraulic impedance of the cold plate section was calculated.

5. The data center liquid-cooled manifold self-flow equalization control method according to claim 4, characterized in that, Methods for calculating the disturbance coefficient and the hydraulic identification confidence coefficient include: Collect the branch traffic flow of newly added branches and existing branches during the trial phase; The maximum value between the difference between the baseline flow of the existing branch and the branch flow during the trial phase and zero is set as the flow drop. The disturbance coefficient of the new branch is calculated based on the flow drop and the branch flow during the trial phase. The hydraulic identification reliability coefficient of the newly added branch is calculated based on the branch flow, initial target flow, trial phase data, and disturbance coefficient during the trial phase.

6. The data center liquid-cooled manifold self-flow equalization control method according to claim 5, characterized in that, For newly added branches, methods for generating progressive target flow sequences include: The target flow rate of the newly added branch is updated based on the server node power consumption, branch outlet temperature and branch inlet temperature, and the final target flow rate is obtained after limiting processing; Based on the hydraulic impedance, disturbance coefficient, and hydraulic identification reliability coefficient of the cold plate section of the newly added branch under the trial opening, the total number of control stages for the corresponding newly added branch is determined. For each control stage, the target flow of the control stage is calculated based on the asymptotic coefficient, the branch flow of the trial stage, and the final target flow. The asymptotic coefficient satisfies a monotonically increasing relationship and the asymptotic coefficient of the last control stage is equal to 1. The progressive target flow sequence includes the total number of control stages for the new branch, the control stage number, the progressive coefficient for each control stage, and the target flow for each control stage.

7. The data center liquid-cooled manifold self-flow equalization control method according to claim 1, characterized in that, For branch expansion, methods for generating progressive target flow sequences include: The target flow rate of the expanded branch is updated based on the server node power consumption, branch outlet temperature and branch inlet temperature, and then the target flow rate of the expanded branch is obtained after limiting processing. Based on the target flow rate of the expanded branch, the current flow rate of the expanded branch, the target valve opening corresponding to the target flow rate of the expanded branch, the current valve opening of the expanded branch, and the preset basic stage number, determine the total number of control stages for the corresponding expanded branch. Based on the current branch flow of the expansion branch, the target flow of the expansion branch, the total number of control stages of the expansion branch, and the asymptotic coefficients corresponding to each control stage, the asymptotic target flow sequence of the expansion branch is determined.

8. The data center liquid-cooled manifold self-flow sharing control method according to claim 1, characterized in that, Methods for determining whether to enter the buffer mode and reallocate the target traffic to the remaining branches include: Subtract the reference bypass flow from the reference manifold total flow, and add the preset branch flow correction constant to obtain the correction denominator; divide the reference flow of the removed branch by the correction denominator to obtain the flow percentage. When the flow rate ratio is greater than the preset threshold for the flow rate ratio of the removed branch, the system enters the slow release mode. In the slow release mode, the bypass valve and variable frequency pump in the controllable actuator are adjusted based on the manifold pressure difference. The set of all branches in the existing branch set, excluding the removed branches, is determined as the remaining branch set. Target traffic is allocated to each branch in the remaining branch set according to power consumption weight, which is the quotient obtained by dividing the power consumption of the server node of the branch by the sum of the power consumption of the server nodes of all branches in the remaining branch set.

9. The data center liquid-cooled manifold self-flow equalization control method according to claim 1, characterized in that, Methods for updating manifold hydraulic fingerprints include: After the branch topology change event ends, the steady-state moment is re-determined and the baseline operating data after the event ends is collected; For each branch in the current branch set, the product of the preset historical weight coefficient and the combined hydraulic impedance before the update, plus the product of the remaining weight and the combined hydraulic impedance calculated based on the baseline operating data after the event ends, is used as the updated combined hydraulic impedance. The remaining weight is 1 minus the preset historical weight coefficient. The updated valve section hydraulic impedance and cold plate section hydraulic impedance are calculated based on the updated combined hydraulic impedance and the baseline valve opening after the event ends. Replace the corresponding data in the manifold hydraulic fingerprint with the updated current branch set, the baseline operating data after the event ends, and the hydraulic impedance data.

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