A pipeline switching and system resetting method after fault recovery of an energy storage liquid cooling system

Abstract

The present application relates to a kind of energy storage liquid cooling system pipeline switching and system reset method after failure recovery.The core scheme includes: after obtaining system reset instruction, control new liquid cooling machine and operating machine same frequency low-speed start, keep switching valve open, isolation valve is closed, and establish communication loop pre-equilibrium;Pipe state stability criterion is obtained by differential pressure and temperature difference continuous stable analysis, and seamless flow state is obtained according to the action lag time window and operation;During monitoring comparison normal operating machine and fault side upstream state obtains switching safety check;Confirm isolation valve open, switching valve is closed, and operate double machine to obtain double independent operation;Check integrated situation to generate system recovery normal integrated check report;According to report, execute reset or back, complete switching and reset.The scheme can automatically realize high safety, continuity, balance and traceable liquid cooling system automatic switching.

Description

Technical Field

[0001] This invention relates to the field of fault switching and automatic reset control technology for energy storage liquid cooling systems, and in particular to a method for pipeline switching and system reset after fault recovery in an energy storage liquid cooling system. Background Technology

[0002] Existing liquid cooling systems for energy storage are widely used in large-scale energy storage power stations, data centers, and power battery packs for new energy vehicles, providing reliable heat dissipation support for battery modules and key electronic units. Current mainstream technologies often employ dual-machine, dual-path independent liquid cooling loops, redundant bridging pipelines, and solenoid valve switching structures to achieve emergency merging, rapid fault isolation, and automatic system reset. Typical system designs require seamless switching back to dual-path operation mode after a failure or replacement of the liquid cooler or pipeline components, ensuring that coolant flow and temperature remain within safe ranges. To this end, the industry commonly equips control units linked to pressure, temperature, and flow sensors, using preset valve action sequences to achieve emergency bridging and recovery switching.

[0003] Mainstream automatic reset control processes largely rely on valve action timing and fluid dynamics criteria. The system typically achieves reset by replacing the faulty liquid cooler, performing a low-frequency synchronous start-up, opening the bridging path, slowly charging the independent loop, and synchronously increasing the pump speed after valve switching. The verification mechanisms for parameters such as pressure, temperature, and flow rate in various control strategies are continuously iterating and optimizing, with the development trend still focusing on improving reset speed, reducing fluid impact, and enhancing redundancy. Furthermore, some high-end systems are attempting to introduce machine learning methods for intelligent analysis of sensor data, hoping to achieve higher automation and fault warning capabilities; however, significant gaps remain in the status feedback of key valve components.

[0004] However, existing technologies typically only consider the consistency of valve action commands and indirect criteria from sensor data, lacking direct feedback and closed-loop confirmation of the physical state of critical components such as check valves. Current systems fail to confirm the mechanical state of check valves in real time during the establishment of independent loops on the fault side and the disconnection of bridging pipelines. This leads to potential reset failures after pipeline switching, or secondary anomalies triggered by check valve malfunctions or jamming, affecting system high availability. Especially in fully automated reset processes, the main control unit cannot provide timely alarms, action reversals, or closed-loop protection based on check valve status. Therefore, the system often suffers from repeated reset failures, cooling circuit failures, and the risk of thermal runaway due to the lack of mechanical feedback. Summary of the Invention

[0005] This application provides a method for pipeline switching and system reset after fault recovery of an energy storage liquid cooling system, aiming to solve the problem of potential reset failure after pipeline switching in an energy storage liquid cooling system mentioned in the background art.

[0006] This application provides a method for pipeline switching and system reset after fault recovery of an energy storage liquid cooling system, specifically including:

[0007] S1: Obtain the system reset command after the faulty liquid chiller is replaced, control the newly replaced liquid chiller to start synchronously at low speed with the currently running liquid chiller, keep the switching valve fully open and the isolation valve fully closed, and establish a pre-balanced working condition for the connected loop.

[0008] S2: Based on the pre-balanced working condition of the connected loop, a continuous stability analysis of the pressure difference and temperature difference is performed to obtain the stability criterion of the pipeline state.

[0009] S3: The stability criterion of the pipeline state is processed to obtain the action lag time window. The isolation valve and the switching valve are processed according to the action lag time window to obtain the seamless flow state.

[0010] S4: During the seamless flow period, the status of the normally operating liquid cooler and the upstream of the faulty pipeline are monitored and compared in real time to obtain the safety verification result of the switching process;

[0011] S5: After confirming that the isolation valve is fully open and the switching valve is fully closed based on the safety verification results of the switching process, operate the two liquid chillers to obtain the target operating condition of dual-path independent operation;

[0012] S6: Based on the target operating conditions of dual-path independent operation, check the overall condition of the liquid chiller and generate a comprehensive verification report on system recovery to normal operation;

[0013] S7: Based on the comprehensive verification report of the system recovery, perform a reset or rollback operation on the energy storage liquid cooling system, and finally complete the pipeline switching and system reset after the energy storage liquid cooling system fault recovery.

[0014] The pipeline switching and system reset method provided in this application for a fault recovery of an energy storage liquid cooling system has the following beneficial effects:

[0015] This solution introduces a dynamic reset mechanism for the liquid cooling system based on real-time sensor feedback, enabling low-speed synchronous startup of both units and pre-balancing of the bridging pipeline after a fault replacement. This significantly improves the safety of the reset operation and the system's fault tolerance and recovery capabilities. Simultaneously, by constructing a multi-stage collaborative control and closed-loop feedback adjustment system, the isolation valve and bridging switching valve are opened and closed gradually and slowly. This is supplemented by high-frequency sampling monitoring and abnormal freeze protection, achieving seamless and smooth transfer of cooling flow and rapid adaptive adjustment under disturbance conditions. After reset, this is further combined with synchronous speed ramp-up and independent fine-tuning of the outlet temperature. This effectively solves the restart problem after replacing the liquid cooler, making it particularly suitable for applications with stringent requirements for thermal management continuity and safety, such as large-scale electrochemical energy storage. Attached Figure Description

[0016] Figure 1This is the main flowchart of a pipeline switching and system reset method after a fault recovery of an energy storage liquid cooling system.

[0017] Figure 2 This is a sub-flowchart of a pipeline switching and system reset method after a fault recovery of an energy storage liquid cooling system.

[0018] Figure 3 This is another sub-flowchart of a pipeline switching and system reset method after a fault recovery of an energy storage liquid cooling system. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] The following disclosure provides many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0021] like Figure 1 As shown, this application provides a method for pipeline switching and system reset after fault recovery of an energy storage liquid cooling system, specifically including:

[0022] S1: Obtain the system reset command after the faulty liquid chiller is replaced, control the newly replaced liquid chiller to start synchronously at low speed with the currently running liquid chiller, keep the switching valve fully open and the isolation valve fully closed, and establish a pre-balanced working condition for the connected loop.

[0023] S2: Based on the pre-balanced operating condition of the connected loop, a continuous stability analysis of the pressure difference and temperature difference is performed to obtain the stability criterion of the pipeline state.

[0024] S3: The stability criterion of the pipeline state is processed to obtain the action lag time window. The isolation valve and the switching valve are processed according to the action lag time window to obtain the seamless flow state.

[0025] S4: During the seamless flow period, the status of the normally operating liquid cooler and the upstream of the faulty pipeline are monitored and compared in real time to obtain the safety verification result of the switching process.

[0026] S5: After confirming that the isolation valve is fully open and the switching valve is fully closed based on the safety verification results of the switching process, operate the two liquid chillers to obtain the target operating condition of dual-path independent operation.

[0027] S6: Based on the target operating conditions of dual-path independent operation, check the overall condition of the liquid chiller and generate a comprehensive verification report on system recovery to normal.

[0028] S7: Based on the comprehensive verification report of the system recovery, perform a reset or rollback operation on the energy storage liquid cooling system, and finally complete the pipeline switching and system reset after the energy storage liquid cooling system fault recovery.

[0029] like Figure 2 As shown, step S1 involves obtaining the system reset command after replacing the faulty liquid chiller, controlling the newly replaced liquid chiller to start synchronously at low speed with the currently operating liquid chiller, keeping the switching valve fully open and the isolation valve fully closed, and establishing a pre-balanced operating condition for the connected loop. Specifically, this includes:

[0030] S1.1: Obtain the system reset command and the current system operating mode flag after the faulty liquid chiller has been replaced. Perform legality verification and timing alignment processing on the received reset command to generate a reset control reference signal containing the identity of the newly replaced liquid chiller and the target low-frequency speed setting value.

[0031] After receiving the system reset command and the current system operating mode flag after the faulty liquid chiller has been replaced, the system performs integrity verification on the data frame structure of the reset command to confirm the legality of the command source and the validity of the timestamp.

[0032] The newly replaced liquid chiller identification field in the reset command is parsed and compared with the physical port mapping relationship recorded in the system topology database to identify the specific liquid chiller component to be reset.

[0033] Read the current system running mode flag to determine if the system is in stand-alone emergency running state. If the flag does not match, refuse to execute the reset process and generate an error log.

[0034] Based on the preset low-frequency safe speed threshold and the rated speed parameters of the newly replaced liquid chiller, the target low-frequency speed setting value is calculated. This setting value is usually 10% to 15% of the rated speed to ensure smooth fluid mixing.

[0035] The identification of the newly replaced liquid chiller and the calculated target low-frequency speed setpoint are encapsulated into a reset control reference signal. This signal contains key control parameters such as device ID, target frequency, and start-up timing offset.

[0036] The reset control reference signal is sent to the underlying drive controller via the data bus, serving as a unified logic reference for subsequent dual-machine synchronous start-up and valve position control.

[0037] By verifying the validity of the reset command and aligning its timing, the system status information from the previous step is transformed into a reset control reference signal containing clear device information and operating parameters, thereby achieving secure access and precise initialization of the reset process.

[0038] For example, the main control unit receives a reset command from the maintenance terminal, carrying a timestamp T=1715623400s and device ID=LCU_02. The system verifies that the timestamp deviation is less than 5s and the ID exists in the standby node list, confirming it as a valid command. The system mode flag is read as Single_Emergency_Mode, meeting the reset prerequisite. The low-frequency safe speed threshold is set to 300rpm, the rated speed of LCU_02 is 3000rpm, and the target low-frequency speed is calculated to be 300rpm. A reset control reference signal {Device: LCU_02, Target_RPM: 300, Start_Offset: 0ms} is generated and sent to the inverter drive interface to ensure that the new unit is introduced into the system in a low-disturbance manner.

[0039] S1.2: Based on the reset control reference signal, send a synchronization frequency adjustment command to the newly replaced liquid chiller and the currently running liquid chiller, and execute the dual-machine low-frequency speed closed-loop coupling control method to generate a dual-machine synchronous low-speed operation state with the same rotation frequency characteristics.

[0040] The system receives the target low-frequency speed setting value and the identification of the newly replaced liquid chiller from the reset control reference signal, and then parses out the frequency reference parameters and phase alignment requirements for synchronous operation of the two machines.

[0041] Based on the frequency reference parameters, the real-time rotor electrical angle and speed feedback values ​​of the currently operating liquid cooler are read and used as the main reference shaft signal input to the main control terminal of the dual-machine low-frequency speed closed-loop coupling control method.

[0042] The Park transformation is used to transform the three-phase stator current of the newly replaced liquid chiller motor from the stationary coordinate system to the synchronous rotating coordinate system. The direct-axis current component and the quadrature-axis current component are extracted to construct the current inner loop feedback variable for torque control.

[0043] A proportional-integral controller is used to perform closed-loop regulation of the direct-axis and quadrature-axis current errors, generating voltage vector commands. The drive waveform is then synthesized using space vector pulse width modulation technology to ensure that the output torque of the newly replaced liquid cooler is smooth and shock-free.

[0044] A virtual spindle synchronization mechanism is introduced to calculate the phase deviation between the rotor position of the newly replaced liquid chiller and the position of the main reference shaft. The electrical angular frequency of the newly replaced liquid chiller is dynamically adjusted through a phase-locked loop method to eliminate the speed slip caused by the difference in mechanical inertia.

[0045] The speed difference between the impellers of the two liquid chillers is monitored in real time. When the speed difference converges to a preset small threshold range, the frequency tracking status of the newly replaced liquid chiller is locked to maintain the stable operation of both machines at the same low frequency speed.

[0046] By using the above-mentioned dual-machine low-frequency speed closed-loop coupling control method, the reset control reference signal is transformed into a dual-machine synchronous low-speed operation state with the same rotation frequency characteristics, thereby realizing the establishment of fluid driving force balance before the pre-filling of the fault-side pipeline and providing a stable power source foundation for the thermal balance of the subsequent bridge pipeline.

[0047] For example, the target low-frequency speed is set to 15% of the rated speed, i.e., 450 rpm. The main control unit uses the running liquid chiller as a reference and performs PI regulation on the newly replaced liquid chiller, with a proportional coefficient set to 0.8 and an integral time constant set to 0.05 s. After 2 seconds of dynamic adjustment, the speed of the newly replaced liquid chiller stabilizes in the range of 448-452 rpm, with a phase deviation of less than 5 degrees. The synchronization error between the two chillers is controlled within 1%, effectively avoiding the water hammer effect in the pipeline caused by sudden speed changes and ensuring a smooth start-up under pre-balancing conditions.

[0048] S1.3: Based on the dual-machine synchronous low-speed operation state, read the current position feedback signals of the switching valve group and the isolation valve group of the fault side water inlet and outlet on the bridge pipeline, make logical judgments on the valve position deviation and output a forced position control command to generate an initial valve position topology structure in which the switching valve group is in the fully open position and the isolation valve group is in the fully closed position.

[0049] The system receives a dual-machine synchronous low-speed operation status signal as the trigger condition for valve position logic judgment. It reads the Hall sensor or limit switch feedback signals from the switching valve group (solenoid valves 5 and 6) and the isolation valve group (solenoid valves 1 and 2) on the fault side of the bridge pipeline to obtain the discrete status code of the current physical valve position. The system compares the read actual valve position status code bit by bit with the preset target topology status code, where the target state is defined as the switching valve group fully open (logic 1) and the isolation valve group fully closed (logic 0). It calculates the Hamming distance between the actual state and the target state; if the Hamming distance is greater than zero, a valve position deviation is determined. For valves with deviations, a forced position control command pulse is generated to drive the actuator until the feedback signal matches the target state. A secondary verification is performed on valves that have completed their actions to ensure stable closing or opening of mechanical contacts, eliminating misjudgments caused by mechanical vibration. Through this closed-loop verification mechanism, the dual-machine operation status of the previous step is transformed into determined initial valve position topology data, achieving accurate initialization of pipeline connectivity and providing a reliable physical link foundation for subsequent pre-balancing conditions.

[0050] For example, after the system detects that the liquid cooler 1 has been replaced and started low-frequency synchronous operation, the main control unit reads the status of solenoid valves 1, 2, 3, 4, 5, and 6. The preset target topology is: solenoid valves 5 and 6 are open (state 1), solenoid valves 1 and 2 are closed (state 0), and solenoid valves 3 and 4 remain open (state 1). If the system reads that solenoid valve 5 has a feedback of 0 (closed) and solenoid valve 1 has a feedback of 1 (open), the state deviation is calculated. The main control unit immediately sends an opening pulse to solenoid valve 5 and a closing pulse to solenoid valve 1. After a 50ms delay, the system reads again and confirms that solenoid valve 5 has changed to 1 and solenoid valve 1 has changed to 0. At this time, all valve states conform to the preset topology, and the system locks the valve position configuration to ensure that the coolant circulates only through the bridge pipeline, preventing unbalanced coolant from directly entering the faulty module, significantly improving the safety of the reset process.

[0051] S1.4: Utilizing the fluid driving force generated by the initial valve position topology and the synchronous low-speed operation of the two machines, the coolant in the outlet pipe of the newly replaced liquid chiller and the outlet pipe of the running liquid chiller are mixed and driven to generate a pre-balanced working condition of a connected loop containing the circulating driving force of the two liquid chillers.

[0052] Based on the initial valve position topology and the synchronous low-speed operation of both machines, the newly replaced liquid chiller pump and the operating liquid chiller pump simultaneously generate fluid driving force. The two coolant streams converge at the junction of the bridging pipeline via their respective outlet pipes. With the switching valve fully open and the faulty isolation valve fully closed on the bridging pipeline, the merged coolant forms a single closed-loop circulation circuit. This circuit encompasses both liquid chillers, the bridging pipeline, and the normal-side battery module flow path. The coolant continuously circulates within the circuit, utilizing the fluid turbulence mixing effect to eliminate the temperature gradient between the old and new pipelines. Low-frequency rotation speed limits the fluid kinetic energy, preventing mechanical stress damage to the newly replaced components from high-pressure impacts. As the circulation time progresses, trapped air in the new liquid chiller side pipeline is gradually expelled and integrated into the main circulation system. The pressure values ​​at each node within the pipeline tend to equalize due to the connectivity effect, eliminating the static pressure difference caused by shutdown. Temperature sensors detect an exponential decrease in the temperature difference between the two ends of the bridging pipeline with increasing circulation frequency. When the temperature difference converges to a preset threshold and the standard deviation of pressure fluctuation is lower than a set limit, it is determined that the thermodynamic and hydraulic states have reached a dynamic equilibrium. Through the above-mentioned flow mixing drive process, the static valve position configuration of the previous step is transformed into a pre-balanced working condition of a connected loop containing the circulating drive force of two liquid chillers, realizing seamless integration of the fault-side pipeline and the main system in terms of thermodynamic parameters, and providing stable fluid boundary conditions for smooth valve switching in the future.

[0053] For example, the dual-machine synchronous low-frequency speed is set to 20% of the rated speed, i.e., 600 rpm. The bridge pipe length is 5 meters and the inner diameter is 20 mm. Initially, the temperature of the pipe on the new liquid cooler side is 25°C, and the temperature of the pipe on the operating side is 18°C. After 120 seconds of low-frequency cycle drive, the temperature difference between the two ends of the bridge pipe drops from 7°C to less than 0.5°C. The pressure sensor shows that the pressure difference between the two ends stabilizes from the initial 0.02 MPa to below 0.001 MPa. At this time, the system determines that the pre-balancing condition is met and outputs a pre-balancing condition confirmation signal to ensure that there is no risk of thermal shock or water hammer effect during subsequent switching.

[0054] Step S2: Based on the pre-balanced operating condition of the connected loop, perform continuous stability analysis on the pressure difference and temperature difference to obtain the stability criteria for the pipeline. Specifically, this includes:

[0055] S2.1: Obtain the original signals of the first pressure sensor and the first temperature sensor located at both ends of the bridge pipeline near the inlet of the switching valve. Perform median filtering and noise reduction processing on the original signal of the first pressure sensor to eliminate high-frequency electromagnetic interference, and perform linear interpolation completion processing on the original signal of the first temperature sensor to repair communication packet loss points. Generate a high-precision real-time pressure sequence and a high-precision real-time temperature sequence of the bridge pipeline containing timestamp alignment.

[0056] S2.2: Based on the real-time pressure sequence of the high-precision bridge pipeline, calculate the real-time difference between the pressure values ​​at the beginning and end of the bridge pipeline to obtain the instantaneous pressure deviation value, and based on the real-time temperature sequence of the high-precision bridge pipeline, calculate the real-time difference between the temperature values ​​at the beginning and end of the bridge pipeline to obtain the instantaneous temperature deviation value. Use a sliding time window mechanism to continuously sample and aggregate the instantaneous pressure deviation value and the instantaneous temperature deviation value to generate a dynamic pressure difference dataset and a dynamic temperature difference dataset of the bridge pipeline containing historical trend features.

[0057] Receive the high-precision real-time pressure sequence and high-precision real-time temperature sequence of the bridge pipeline after processing by S2.1, and extract the pressure value at the beginning and end of the bridge pipeline, as well as the temperature value at the beginning and end, corresponding to the current sampling time t.

[0058] Based on the definition of pressure difference in fluid mechanics, the instantaneous pressure deviation is calculated, and the dynamic characteristics of the pressure are determined using the following formula:

[0059]

[0060] in, The instantaneous pressure deviation at time t. For the initial pressure, This refers to the end pressure.

[0061] Simultaneously calculate the instantaneous temperature deviation value and generate dynamic temperature indicators using a thermodynamic temperature difference model:

[0062]

[0063] in, Let be the instantaneous temperature deviation at time t. For the initial temperature, This refers to the terminal temperature.

[0064] Construct a sliding time window of length N, and store the instantaneous pressure deviation and instantaneous temperature deviation values ​​at the current moment and the previous N-1 sampling periods into a buffer queue.

[0065] Continuous sampling and aggregation are performed on the pressure deviation sequence within the sliding window to generate a dynamic differential pressure dataset for bridge pipelines that includes historical fluctuation characteristics.

[0066] Continuous sampling and aggregation are performed on the temperature deviation sequence within the sliding window to generate a dynamic temperature difference dataset of the bridge pipeline containing historical thermal inertia features.

[0067] By integrating instantaneous deviation data through a sliding window mechanism, the discrete measurements at a single point are transformed into a dynamic dataset reflecting the hydraulic and thermal balance trend of the system. This enables a multi-dimensional quantitative characterization of pipeline stability and provides a data foundation for the generation of subsequent stability criteria.

[0068] S2.3: Perform standard deviation calculation on the dynamic pressure difference dataset of the bridge pipeline to extract the pressure fluctuation dispersion index, and perform standard deviation calculation on the dynamic temperature difference dataset of the bridge pipeline to extract the temperature fluctuation dispersion index. Perform a first-level logical comparison between the pressure fluctuation dispersion index and a preset pressure stability threshold, and simultaneously perform a second-level logical comparison between the temperature fluctuation dispersion index and a preset temperature stability threshold to generate a pressure transient stability flag bit and a temperature transient stability flag bit that include the single-point compliance state.

[0069] The system receives dynamic differential pressure datasets and dynamic temperature difference datasets from the pipeline as input sources for calculating the fluctuation dispersion. It performs mean calculations on multiple consecutive sampling points in the dynamic differential pressure dataset to determine the central trend benchmark of the pressure deviation. Based on this central trend benchmark, it calculates the squared difference between each sampling point and the mean, constructing a pressure fluctuation energy distribution matrix. The pressure fluctuation energy distribution matrix is ​​summed and divided by the sample size minus one to obtain the pressure variance value. The square root operation is performed on the pressure variance value to extract the pressure fluctuation dispersion index, quantifying the transient oscillation amplitude of the fluid pressure within the pipeline.

[0070] The same statistical logic is simultaneously applied to the dynamic temperature difference dataset to calculate the temperature fluctuation dispersion index, which characterizes the uniformity of coolant heat exchange. The calculated pressure fluctuation dispersion index is then compared with a preset pressure stability threshold of 0.05 bar. If the pressure fluctuation dispersion index is less than or equal to 0.05 bar, the pressure field is considered to have reached a steady state, and the pressure transient stability flag is set to true; otherwise, it is set to false. The temperature fluctuation dispersion index is then compared with a preset temperature stability threshold of 0.2℃. If the temperature fluctuation dispersion index is less than or equal to 0.2℃, the temperature field is considered to have reached a steady state, and the temperature transient stability flag is set to true; otherwise, it is set to false.

[0071] Through the above standard deviation statistical analysis and dual threshold logic comparison processing, the original sensing time series data is transformed into Boolean state flags that characterize the dual stability of hydraulics and thermodynamics, realizing the quantitative confirmation of the pipeline pre-balance state and providing a highly reliable safety access basis for subsequent valve actions.

[0072] S2.4: Construct a joint stability judgment vector based on the pressure transient stability flag and the temperature transient stability flag. Use a duration counter to accumulate the length of time the joint stability judgment vector remains in a true state. Compare the accumulated current continuous stable duration with a preset minimum stable duration threshold using third-level logic. If the current continuous stable duration is greater than or equal to the preset minimum stable duration threshold, output a confirmation signal to generate a pipeline stability criterion that characterizes the pipeline's hot water hydraulic state as reaching equilibrium.

[0073] The system receives the pressure transient stability flag and temperature transient stability flag generated in the previous step, and combines the two Boolean state signals to construct a joint stability judgment vector. This vector is used to characterize whether the pipeline thermodynamic parameters at the current moment simultaneously meet the static fluctuation threshold requirements.

[0074] Initialize the duration counter, setting the counting step size to the data sampling period of the system's main control unit. Within each sampling period, the logic state of the joint stability judgment vector is polled and detected in real time.

[0075] When the joint stability judgment vector is detected to be in a true state, the duration counter performs an accumulation operation, increasing the current count value by the length of one sampling period. If any flag bit in the joint stability judgment vector is false, the duration counter is immediately reset to zero to eliminate interference data that momentarily meets the criteria but is not continuously stable.

[0076] The current duration of sustained stability is accumulated and compared with the preset minimum stability threshold. The minimum stability threshold is set based on the thermal inertia time constant of the liquid cooling system and the fluid mixing and diffusion rate to ensure that the coolant in the pipeline completes sufficient heat exchange and pressure equalization.

[0077] If the current sustained stable duration is greater than or equal to the preset minimum stable duration threshold, a high-level confirmation signal is output, generating a pipeline stability criterion that characterizes the pipeline's hot water hydraulic state as having reached equilibrium. This criterion serves as the sole enabling condition for triggering subsequent valve switching actions.

[0078] By using a duration-based cumulative verification process, the discrete compliance status of transient sensor data is transformed into a continuous and stable criterion with a time dimension. This achieves the expected technical effect of eliminating the influence of sensor noise jitter and transient fluid disturbances, ensuring that the switching action is performed only when the system truly reaches thermodynamic equilibrium.

[0079] For example, the system sampling period is set to 100ms, the preset pressure stability threshold is 0.05MPa, the preset temperature stability threshold is 0.5℃, and the preset minimum stability duration threshold is 30s. Under pre-balancing conditions, the calculated standard deviation of the pressure difference at both ends of the bridge pipeline is 0.03MPa, and the standard deviation of the temperature difference is 0.2℃, both lower than their respective thresholds, and the joint stability judgment vector is true. The duration counter starts accumulating from 0. When the accumulated duration reaches 30s, the switching condition is determined to be met, and the stability criterion is output. If, at 25s, a slight fluctuation in the pump frequency causes the standard deviation of the pressure difference to jump instantaneously to 0.06MPa, the joint vector becomes false, the counter is reset to zero and the timing restarts until it stabilizes continuously for another 30s before outputting the criterion, effectively avoiding the risk of erroneous switching.

[0080] like Figure 3 As shown, step S3 involves processing the pipeline stability criterion to obtain an action lag time window, and then performing calculations on the isolation valve and switching valve based on the action lag time window to obtain a seamless flow state. Specifically, this includes:

[0081] S3.1: Based on the pipeline stability criterion, the opening control command of the isolation valve for the inlet and outlet water on the fault side is processed by pulse width modulation to generate a slow opening drive signal for the isolation valve with an extremely low rate of change, thereby obtaining an initial valve opening increment sequence for gradually establishing the flow of the independent loop on the fault side.

[0082] The system receives a pipeline stability criterion as a trigger signal and extracts the current mechanical position feedback value of the isolation valves at the inlet and outlet of the faulty side, along with the target fully open position threshold. A time-axis-based linear pulse width modulation (PWM) control model is constructed, setting the total transition time and minimum step time interval for valve action to ensure the opening change rate is below a preset safe fluid impact threshold. The total opening stroke is divided into several small intervals, and the duty cycle increment within each time step is calculated to generate a discretized PWM drive pulse sequence. A low-pass filter is applied to this pulse sequence to smooth motor torque fluctuations and eliminate mechanical vibration noise caused by high-frequency harmonics. The processed drive signal is mapped to the phase sequence excitation command of the stepper motor, controlling the isolation valve core to displace at a constant low speed along the opening direction. Feedback data from the valve stem displacement sensor is collected in real time, and the deviation between the theoretical and actual opening is calculated. If the deviation exceeds the allowable error band, the pulse width of the next cycle is dynamically adjusted for compensation and correction. By using the pulse width modulation processing method described above, the stability criterion of the previous step is transformed into a slow opening drive signal for the isolation valve with an extremely low rate of change, thereby obtaining an initial valve opening increment sequence for gradually establishing the flow of the independent loop on the fault side, and realizing smooth flow channel opening without hydraulic shock.

[0083] For example, the total transition time from fully closed to fully open of the isolation valve is set to 60 seconds, and the control system sampling period is 100 milliseconds. The valve stroke is linearly divided into 600 step points, each step point corresponding to an opening increment of 0.167%. The PWM carrier frequency is set to 1kHz, with an initial duty cycle of 0%, increasing linearly to 100% over time. Within each 100-millisecond control cycle, the main control unit outputs a pulse signal corresponding to the duty cycle to drive the stepper motor. If the actual opening lags behind the theoretical value by more than 0.5%, a 2% duty cycle compensation is added in the next cycle. This ultimately generates an opening increment sequence containing 600 elements, ensuring that the coolant flow rate is slowly injected into the faulty side pipeline at a rate of 0.5 liters / minute, effectively avoiding sudden pressure changes.

[0084] S3.2: Using the initial valve opening increment sequence, perform timing offset calculation processing on the switching valve closing action on the bridge pipeline to generate a switching valve cooperative closing drive strategy containing delay time parameters, thereby obtaining the action lag time window of the switching valve near the operating liquid cooler side relative to the faulty isolation valve.

[0085] Receive the initial valve opening increment sequence generated by S3.1, and extract the target opening rate parameter of the fault-side isolation valve and the mechanical response characteristic constant of the switching valve in the bridge pipeline.

[0086] Based on the fluid mechanics continuity equation, a critical pressure balance model to prevent coolant backflow is constructed, and the minimum safe time lag between the switching valve action and the isolation valve action is determined.

[0087] The action lag time window is calculated using the following formula:

[0088]

[0089] in, This refers to the action lag time. The equivalent length of the bridge-connected pipeline. For coolant density, The cross-sectional area of ​​the pipe. The valve flow coefficient, For the opening speed of the isolation valve, This is the maximum permissible instantaneous pressure difference threshold.

[0090] The calculated motion lag time is compared with the minimum resolution of the system control cycle. If the motion lag time is less than the control cycle, it is forcibly set to one control cycle to ensure the discrete control accuracy of the actuator.

[0091] Based on the corrected lag time parameters, a switching valve cooperative shutdown drive strategy containing delayed start commands is generated, clarifying the specific delay time of the switching valve near the operating liquid chiller after the isolation valve opening action begins.

[0092] Through the above time offset calculation and processing, the initial valve opening increment sequence is transformed into a switching valve cooperative closing drive strategy containing precise timestamps. This obtains the action lag time window of the switching valve on the side closer to the operating liquid cooler relative to the isolation valve on the faulty side, realizing a seamless switching logic of first establishing a new path and then cutting off the old path, effectively avoiding the risks of sudden changes in pipeline pressure and coolant backflow.

[0093] S3.3: Based on the action lag time window, perform linkage interpolation calculation on the real-time opening of the isolation valve for the inlet and outlet of the fault side and the switching valve of the bridging pipeline to generate a valve coordinated motion trajectory curve that conforms to the logic of first opening and then closing, thereby obtaining a seamless flow state in which the flow rate of the independent loop on the fault side gradually increases while the flow rate of the bridging pipeline gradually decreases.

[0094] The system receives the action lag time window parameters and the initial opening increment sequence of the isolation valve, and constructs a time-axis-based valve collaborative control model. Based on the "on first, off later" logic, it sets the coupling relationship between the opening growth function of the fault-side isolation valve and the opening decay function of the bridging switching valve to ensure that the total flow cross-sectional area of ​​the system remains constant or slightly increases at any time, thereby maintaining stable pipeline pressure.

[0095] The target opening trajectory of the isolation valve within the lag time window is calculated using a linear interpolation method. The time axis is discretized into tiny control cycles, and the theoretical opening of the isolation valve in each cycle is calculated in real time to generate a smoothly increasing sequence of opening commands, thus avoiding hydraulic shocks caused by step changes.

[0096] The target closing trajectory of the switching valve in the bridge pipeline is calculated synchronously, and a delay compensation coefficient is introduced to make the starting point of the switching valve's action lag behind the starting point of the isolation valve's action, forming a time overlap buffer period.

[0097] The generated isolation valve opening trajectory and switching valve closing trajectory are superimposed and verified. The algebraic sum of the opening change rates of the two valves is calculated to ensure that the net flow fluctuation rate during the flow transfer process is lower than a preset threshold. If an instantaneous flow fluctuation is detected to exceed the safe bandwidth, the interpolation step size is dynamically adjusted, and a corrected valve cooperative motion trajectory curve is regenerated.

[0098] The output is a seamless flow data packet containing timestamps, target opening of isolation valves, and target opening of switching valves, which serves as the direct input for subsequent stepper motor pulse frequency adjustment.

[0099] By using a linkage interpolation calculation method, the action lag time window is transformed into a valve coordinated motion trajectory curve that conforms to the logic of first opening and then closing, so as to achieve a seamless switching of the flow rate of the independent circuit on the fault side gradually being established while the flow rate of the bridging path gradually decreases, thus eliminating the risk of fluid pressure oscillation.

[0100] For example, with a lag time window set to 2 seconds, the isolation valve takes 10 seconds to open from 0% to 100%, and the switching valve takes 8 seconds to close from 100% to 0%. During the period from t=0 to t=2 seconds, the isolation valve opening linearly increases from 0% to 20%, while the switching valve remains fully open at 100%. After t=2 seconds, the switching valve begins to close linearly, while the isolation valve continues to open linearly. At t=5 seconds, the isolation valve opening is 50%, and the switching valve opening, calculated according to the formula, is 62.5%. At this point, the total flow capacity of the two valves is slightly higher than the initial state, ensuring continuous coolant flow without interruption. Actual measurements show that under this control strategy, the pipeline pressure fluctuation is controlled within 0.05 MPa, significantly better than the 0.3 MPa pressure shock generated by the traditional step switching method, effectively protecting the internal flow channel structure of the battery module.

[0101] S3.4: Based on the seamless flow state, the pulse frequency of the stepper motor of the valve drive actuator is dynamically corrected by feedback to generate a refined valve position adjustment command that eliminates the influence of mechanical hysteresis, thereby obtaining a fluid channel switching physical state that is highly consistent with the actual valve opening and the theoretical motion trajectory.

[0102] Receive the seamless flow state generated by S3.3, extract the theoretical valve opening sequence and the target action timestamp, and use them as reference input for stepper motor pulse frequency adjustment.

[0103] Read the real-time feedback data from the position encoder built into the valve drive actuator, calculate the instantaneous deviation between the theoretical opening degree and the actual opening degree, and construct a closed-loop feedback signal for the position error.

[0104] Based on the closed-loop feedback signal of position error, a mechanical hysteresis compensation coefficient is introduced, and the pulse frequency correction is calculated using the PID control method to generate a dynamically adjusted pulse frequency command.

[0105] The dynamically adjusted pulse frequency command is sent to the stepper motor driver, which drives the valve core to move along the corrected trajectory, eliminating the lag caused by mechanical friction or fluid resistance.

[0106] The overlap between the valve position feedback signal and the theoretical trajectory is continuously monitored. If the deviation exceeds the preset tolerance threshold, the pulse frequency is further fine-tuned until the actual valve opening is highly consistent with the theoretical motion trajectory.

[0107] By using a dynamic feedback correction process, the theoretical control benchmark is transformed into a refined valve position adjustment command that eliminates the effects of mechanical hysteresis, thereby achieving the expected technical effect of high-precision control for switching the physical state of the fluid channel.

[0108] S3.5: Based on the physical state of the fluid channel switching, the flow rate distribution of the coolant in the fault-side pipeline is continuously verified to generate a flow state switching completion flag indicating that the independent loop is fully established and the bridging path is completely cut off, thereby obtaining the dual-path independent operation readiness conditions to support subsequent system speed increase and temperature fine-tuning operations.

[0109] It receives real-time opening feedback data of the isolation valves for water inlet and outlet on the fault side and the switching valves for the bridge pipeline, and constructs the fluid channel topology state matrix at the current moment by combining it with the preset valve action timing records.

[0110] Based on the fluid channel topology state matrix, the instantaneous flow sensor readings at the inlet of the fault-side pipeline and the pressure sensor readings at the outlet are extracted. The flow data is then subjected to moving average filtering to eliminate pulsation interference, generating a smoothed real-time flow sequence for the fault-side loop.

[0111] Using the smoothed real-time flow sequence of the fault-side loop, the deviation ratio of the current flow value relative to the theoretical target flow value is calculated. At the same time, the residual flow indication at the switching valve of the bridge pipeline is monitored. If the residual flow is lower than the preset cut-off threshold and the flow deviation ratio of the fault side converges to the allowable range, the flow state switching is determined to be initially completed.

[0112] Indirect verification logic for check valve status is introduced. By comparing the pressure drop characteristic curves of the pump outlet pressure on the fault side and the module inlet pressure, if the measured pressure drop conforms to the characteristics of the independent loop hydraulic model and there is no backflow pressure fluctuation, it is confirmed that the check valve is in a normal conducting state rather than stuck or accidentally closed.

[0113] Perform a logical AND operation between the initial flow state switching completion flag and the check valve status normal flag to generate the final flow state switching completion flag, which serves as the sole enable condition for triggering the subsequent dual-machine speed synchronization increase command.

[0114] By using the above-mentioned multi-parameter joint verification processing method, the valve physical position information of the previous step is transformed into a confirmed fluid dynamic stability state index, realizing a reliable closed-loop verification from the mechanical action to the establishment of hydraulic conditions, and ensuring the safety of system reset.

[0115] For example, the target flow rate on the fault side is set to 50 L / min, and the bridge pipeline disconnection threshold is set to 1 L / min. When the actual flow rate on the fault side is detected to be stable in the range of 49.5-50.5 L / min, and the flow rate in the bridge pipeline drops below 0.8 L / min, the flow switching is deemed to have met the standard. Simultaneously, the pump outlet pressure on the fault side is monitored to be 3.0 bar, and the module inlet pressure is 2.2 bar. The pressure difference of 0.8 bar is consistent with the expectations of the independent loop hydraulic model, and there is no reverse pressure fluctuation, confirming that the check valve is working properly. At this point, a flow switching completion flag is generated, allowing the system to enter step S4.

[0116] Step S4: During the seamless flow state, the status of the normally operating liquid cooler and the upstream of the faulty pipeline are monitored and compared in real time to obtain the safety verification result of the switching process. Specifically, this includes:

[0117] S4.1: Obtain the real-time coolant pressure sampling sequence at the outlet of the normally operating liquid cooler and the instantaneous flow indication value of the upstream of the faulty pipeline. Perform sliding window filtering on the real-time coolant pressure sampling sequence to eliminate high-frequency noise interference and generate high signal-to-noise ratio pressure fluctuation characteristic data for subsequent analysis. At the same time, perform timestamp alignment calibration on the instantaneous flow indication value to generate synchronized flow status monitoring data.

[0118] The S4.1 sub-step aims to acquire and preprocess key fluid dynamic parameters during the seamless switching process with high precision, providing a clean data foundation for subsequent safety verification.

[0119] The main control unit synchronously reads the analog signal from the pressure transmitter installed on the outlet pipeline of the normally operating liquid cooler, as well as the pulse count value of the electromagnetic flowmeter deployed upstream of the junction point of the faulty pipeline, at a preset sampling frequency to obtain the raw physical quantity data stream.

[0120] To address the high-frequency noise from pump mechanical vibration mixed into the pressure sampling sequence, a sliding time window of length N is constructed. The discrete pressure data points within the window are then subjected to an arithmetic average to generate smoothed pressure feature values.

[0121] The filtering process calculates the filtered pressure value at time t using the following formula. :

[0122]

[0123] in, This represents the original pressure value of the i-th sampling point before the current time. The value is the sliding window size, determined based on the fundamental frequency vibration period of the liquid chiller.

[0124] For the fault-side traffic indication value, since fluctuations in the communication bus load may cause jitter in the arrival time of data packets, the main control unit extracts the microsecond-level hardware timestamp carried in each traffic data frame.

[0125] A linear interpolation method is used, with the system global clock as the reference, to resample the non-uniformly spaced traffic sampling points to fill the data gaps caused by packet loss or delay.

[0126] The filtered pressure sequence is indexed and matched with the timestamp-aligned flow sequence to ensure that the pressure and flow states within the same control cycle correspond strictly on the time axis.

[0127] By using the sliding window filtering and linear interpolation alignment methods described above, the original sensor signals containing noise and timing jitter are transformed into a pressure-flow joint monitoring dataset with high signal-to-noise ratio and time synchronization, thus achieving the expected technical effect of eliminating measurement interference from misleading the handover safety judgment.

[0128] S4.2: Based on the high signal-to-noise ratio pressure fluctuation characteristic data and the synchronized flow status monitoring data, calculate the derivative of the pressure change rate and the absolute value of the flow deviation at the current moment. Perform dynamic comparison calculation between the derivative of the pressure change rate and the preset pressure allowable bandwidth threshold to generate a pressure safety boundary judgment result. Perform logical comparison between the absolute value of the flow deviation and the set lower limit of the normal flow threshold to generate a flow continuity judgment result.

[0129] The high signal-to-noise ratio pressure fluctuation characteristic data sequence and synchronized flow status monitoring data processed in step S4.1 are received as the input reference for this step.

[0130] Discrete difference operation is performed on the high signal-to-noise ratio pressure fluctuation characteristic data sequence to extract the pressure value change at adjacent sampling times, and a pressure change rate derivative index reflecting the transient pressure response characteristics of the system is constructed.

[0131] The pressure change rate at the current time t is calculated using the central difference method. The derivative of the calculated pressure change rate is then compared in real time with a preset pressure allowable bandwidth threshold, which is set based on the pressure gradient safety margin corresponding to the maximum head of the liquid-cooled pump.

[0132] If the absolute value of the derivative of the pressure change rate is less than or equal to the preset threshold, the hydraulic shock risk is determined to be controllable, and the pressure safety boundary determination result is normal; otherwise, it is determined to be abnormal.

[0133] Based on synchronized flow status monitoring data, the instantaneous feedback value of the upstream flow meter on the faulty side is read and logically compared with 50% of the system's rated total flow as the lower limit of the normal flow threshold.

[0134] The absolute value of the difference between the instantaneous flow rate indication value and the lower limit of the normal flow rate threshold is calculated to quantify the effectiveness of the fault-side loop filling progress.

[0135] If the absolute value of the flow deviation indicates that the actual flow rate is higher than the lower limit of the threshold, it is determined that the coolant has been successfully injected into the faulty side pipeline and there is no air blockage or flow interruption. The flow continuity determination result is continuous.

[0136] If the absolute value of the flow deviation indicates that the actual flow is below the lower limit of the threshold, it is determined that there is a risk of flow channel blockage or pump failure, and the flow continuity determination result is interrupted.

[0137] Through the above differential operation and threshold comparison processing, the raw sensor data from the previous step is transformed into a binary logic criterion characterizing hydraulic stability and fluid connectivity, thereby achieving the expected technical effect of quantitative assessment of the safety of the switching process.

[0138] S4.3: Based on the pressure safety boundary determination result and the flow continuity determination result, execute the multi-condition joint logic verification method. If the pressure change rate derivative exceeds the pressure allowable bandwidth threshold or the absolute value of the flow deviation is lower than the normal flow threshold lower limit, the abnormal interruption mechanism is immediately triggered to generate a valve position freeze signal that keeps the current valve position opening unchanged, so as to prevent the sudden change in the flow of the faulty pipeline from causing system oscillation.

[0139] The pressure safety boundary determination result and flow continuity determination result output by S4.2 are received as input variables for the multi-condition joint logic verification method.

[0140] A logic AND gate circuit model is constructed, and Boolean algebra is used to integrate the abnormal flags where the derivative of the pressure change rate exceeds the threshold and the abnormal flags where the flow deviation is below the lower limit.

[0141] When any input flag is true, the logic gate outputs a high-level trigger signal, activating the execution permission of the exception interrupt mechanism.

[0142] Immediately lock the valve drive command register for the current control cycle and freeze the pulse width modulation duty cycle values ​​of the isolation valve and bridging switching valve for the inlet and outlet water on the fault side.

[0143] Cut off the stepper motor pulse transmission channel, keep the solenoid valve coil current constant, and force the valve core to stay at the current physical opening position.

[0144] Generate a control signal data packet containing a "valve position frozen" status identifier, marking the system as entering a protected state of pause switching.

[0145] By using logical interlocking and hardware freezing, the judgment result of the previous step is transformed into a valve position freezing signal to maintain the stability of the current flow state, thereby achieving the expected technical effect of preventing system oscillation caused by fluid impact.

[0146] For example, a pressure change rate threshold of 5 kPa / s and a lower flow rate threshold of 2 L / min are set. If a pressure change rate of 6 kPa / s is detected, it is considered abnormal. The system immediately freezes the isolation valve opening at 30% and the switching valve opening at 70%. A valve position freeze signal is output, maintaining this state until manual confirmation or the disturbance is eliminated, effectively avoiding the risk of battery module thermal runaway caused by sudden changes in pipeline pressure.

[0147] S4.4: If the multi-condition joint logic verification method confirms that the derivative of the pressure change rate is within the pressure allowable bandwidth threshold and the absolute value of the flow deviation is higher than the lower limit of the normal flow threshold, then the smooth transition allow flag is activated, and a continue execution signal containing the instruction to continue the slow opening of the isolation valve and the cooperative closing of the switching valve in the next cycle is generated to maintain a seamless flow state in which the flow of the fault-side independent loop is gradually established and the flow of the bridging path is gradually reduced.

[0148] Receive the pressure safety boundary determination result and flow continuity determination result output by S4.3, and confirm that the derivative of the pressure change rate at the current moment is within the preset allowable bandwidth and the absolute value of the flow deviation is higher than the lower limit of the normal threshold.

[0149] Based on the aforementioned dual compliance status, the main control unit activates the smooth transition enable flag, which serves as the enable signal for the timing controller, thereby removing the freeze restriction on valve drive commands.

[0150] The valve coordinated motion trajectory interpolation method is invoked to read the theoretical target opening degree of the current isolation valve and switching valve, and to calculate the opening increment step size for the next control cycle.

[0151] The calculated opening increment step size is converted into a stepper motor pulse sequence, which sends a small opening pulse to the isolation valve of the inlet and outlet water on the fault side, and at the same time sends a small closing pulse to the switching valve of the bridge pipeline.

[0152] After the pulse is sent, a short delay waiting mechanism is immediately activated to compensate for the response lag caused by the mechanical transmission gap, ensuring that the physical position of the valve core follows the change of the electrical signal.

[0153] By periodically repeating the above-mentioned opening fine-tuning and delay waiting process, a seamless flow state is maintained in which the flow of the fault-side independent loop increases linearly while the flow of the bridging path decreases linearly, thus achieving a smooth progress in the system reset process.

[0154] For example, the allowable pressure bandwidth threshold is set to ±0.05 MPa / s, and the lower limit of the normal flow rate threshold is 2.0 L / min. When a pressure change rate of 0.02 MPa / s and a flow deviation of 2.5 L / min are detected, the conditions for continuing execution are determined to be met. The main control unit uses a control cycle of 100 ms, increasing the isolation valve opening by 0.5% and decreasing the switching valve opening by 0.5% each time until the switching is complete. This process effectively avoids fluid shock and significantly improves the reset success rate.

[0155] S4.5: Integrate the status information of the valve position freeze signal or continue execution signal, and combine it with the current solenoid valve action timing record to construct a complete status data packet containing the safety verification results of the switching process. Output the complete status data packet to the main control unit as the basis for decision-making, so as to realize the full closed-loop safety monitoring and automatic abnormal back-off protection of the pipeline switching process after the liquid cooling system fault recovery.

[0156] Step S5: After confirming that the isolation valve is fully open and the switching valve is fully closed based on the safety verification results of the switching process, the two liquid chillers are operated to obtain the target operating condition of dual-path independent operation. Specifically, this includes:

[0157] S5.1: Obtain the isolation valve fully open signal and the switching valve fully closed signal as input conditions, call the preset speed increase curve generation method to perform slope constraint processing on the current low frequency speed of the dual liquid cooler, so as to generate a synchronous speed increase command sequence containing time axis and frequency increment, thereby establishing the benchmark driving parameters for synchronous growth of dual coolant flow.

[0158] Receive the safety verification result of the switching process from step S4, and extract the status signal that confirms that the isolation valve of the inlet and outlet water on the fault side is fully open and the switching valve on the bridge pipeline is fully closed, as the logic enable condition for the speed increase stage.

[0159] The pre-stored speed increase curve generation module is invoked to read the real-time speed value of the current dual liquid cooler in low-frequency synchronous operation state, and set it as the starting reference point for speed increase.

[0160] Based on the current charge / discharge rate requirements of the energy storage system and the battery module thermal load prediction model, the rated operating frequency of the liquid cooler under the target operating conditions is determined, and the total frequency increment from the starting reference point to the target frequency is calculated.

[0161] By applying a slope constraint processing mechanism, the frequency increment is smoothly allocated in the time domain, and a synchronous speed ramp command sequence containing time axis nodes and corresponding frequency increments is constructed to ensure that the speed change rate is within the preset safety threshold range and to prevent pipeline pressure oscillation caused by sudden changes in flow.

[0162] Through the above processing method, the valve position stabilization state of the previous step is transformed into a synchronous speed ramp command sequence containing time axis and frequency increment, establishing the benchmark driving parameters for synchronous growth of dual-path coolant flow, and realizing a smooth transition from emergency low-speed mode to full-power operation mode.

[0163] For example, two liquid chillers are currently operating synchronously at a low frequency of 15Hz, and the target operating condition requires an increase to 45Hz. The system is set to a total speed increase time of 60 seconds, with a maximum allowable acceleration of 0.5Hz / s. A linear ramp-up curve is generated, and a command to increase the frequency by 0.5Hz is sent every second until 45Hz is reached. During this process, the main control unit monitors the motor response in real time to ensure that the deviation between the actual speed and the command is less than 0.1Hz, effectively avoiding fluid inertial impact and significantly improving the smoothness of system reset.

[0164] S5.2: Based on the synchronous speed ramp command sequence, drive the two liquid coolers to perform frequency conversion regulation operation, and at the same time collect real-time data from the temperature sensors at the inlet of each battery module. Use the multi-channel temperature deviation calculation model to perform differential calculation on the average inlet temperature of the battery module group corresponding to the two sets of liquid cooling circuits to generate a dual-path temperature deviation vector characterizing the difference in the heat exchange history of the pipeline.

[0165] Upon receiving the synchronous speed ramp command sequence generated by S5.1, the variable frequency drives of the newly replaced liquid chiller and the normally operating liquid chiller are driven to perform frequency adjustment, so that the pump speed of the two liquid chillers is synchronously increased to the target operating frequency according to the preset slope.

[0166] During the speed increase process, the main control unit collects temperature sensor data at the coolant inlet of each battery module in real time with a millisecond sampling period, and obtains the original signal sequence of multi-channel inlet temperature including timestamps.

[0167] Kalman filtering is performed on the original multi-channel inlet temperature signal sequence to eliminate sensor noise interference and generate a high signal-to-noise ratio real-time inlet temperature dataset for each battery module.

[0168] Based on the energy storage system topology, the battery modules are divided into a first module group corresponding to the first liquid cooling circuit and a second module group corresponding to the second liquid cooling circuit, and the real-time inlet temperature data of the two module groups are extracted respectively.

[0169] Calculate the arithmetic mean of the inlet temperatures of all battery modules in the first module group to obtain the average inlet temperature of the first circuit; calculate the arithmetic mean of the inlet temperatures of all battery modules in the second module group to obtain the average inlet temperature of the second circuit.

[0170] Using a multi-channel temperature deviation calculation model, differential calculations are performed on the average inlet temperature of the first loop and the average inlet temperature of the second loop to generate a dual-channel temperature deviation vector that characterizes the difference in the heat exchange history of the two coolants.

[0171] Through the above processing method, the speed adjustment action in the previous step is transformed into a quantified dual-path temperature deviation vector index, which realizes the accurate characterization of the pipeline thermal imbalance state and provides a data basis for subsequent independent temperature fine-tuning.

[0172] S5.3: Based on the dual-path temperature deviation vector as feedback input, the dual-closed-loop independent temperature control strategy is activated, and proportional-integral-derivative adjustment processing is performed on the outlet set temperature values ​​of the two liquid coolers respectively to generate independent outlet temperature correction commands that eliminate the unilateral thermal hysteresis effect, thereby achieving decoupled and precise control of the two coolant outlet temperatures.

[0173] Receive the dual-path temperature deviation vector generated by S5.2, which contains the average inlet temperature difference between the newly replaced liquid cooler side and the normally operating liquid cooler side of the corresponding battery module group.

[0174] Decoupling analysis was performed on the dual-path temperature deviation vector to identify characteristic parameters of the unilateral thermal hysteresis effect caused by differences in pipeline length and heat exchange history.

[0175] A dual-closed-loop independent temperature control model based on the proportional-integral-derivative (PID) method is constructed, and the identified thermal hysteresis effect characteristic parameters are used as feedforward compensation terms input to the control loop.

[0176] For the newly replaced liquid cooler, calculate the residual between the current temperature deviation and the preset target temperature, and use a proportional element to quickly respond to the deviation and generate the basic adjustment amount.

[0177] An integral step is introduced to accumulate historical temperature deviations, eliminating steady-state errors and ensuring temperature consistency during long-term operation.

[0178] By introducing a differential element to predict temperature change trends, suppressing temperature overshoot caused by sudden flow changes, and generating a dynamic damping correction value.

[0179] The basic adjustment, integral accumulation, and dynamic damping correction are linearly superimposed to generate an independent outlet temperature correction command for the newly replaced liquid chiller compressor.

[0180] The same PID closed-loop control logic is executed synchronously on the side of the normally operating liquid cooler, but different integral time constants are used to adapt to its stable thermal characteristics, and corresponding independent outlet temperature correction commands are generated.

[0181] By employing the aforementioned dual-closed-loop independent control strategy, the dual-path temperature deviation vector is transformed into fine-tuning commands for the compressor frequencies of the two liquid chillers, thereby achieving decoupled and precise control of the coolant outlet temperatures and eliminating the effects of unilateral thermal hysteresis.

[0182] For example, the target inlet temperature is set to 25℃. The detected average inlet temperature on the newly replaced side is 26.5℃, and on the normally operating side it is 25.2℃. The dual-path temperature deviation vector is [1.3, 0.2]. For the newly replaced side, the proportional coefficient is set to 2.0, the integral coefficient to 0.5, and the derivative coefficient to 0.1. The calculated proportional term is 2.6, the integral term is accumulated to 0.8, and the derivative term is -0.05. The synthesized correction command reduces the compressor frequency by 15Hz. For the normally operating side, the correction command reduces the frequency by 2Hz. After execution, the temperature difference between the two sides converges to within 0.5℃ within 30 seconds, significantly improving temperature uniformity.

[0183] S5.4: Receive the independent outlet temperature correction command and apply it to the operating frequency of the liquid cooler compressor, continuously monitor the temperature difference trend of each battery module inlet and outlet, and use the thermal balance convergence criterion to iteratively verify the uniformity of the cell temperature distribution in the whole system, so as to generate a system thermal balance state identifier indicating that the thermal characteristics of the pipeline tend to be consistent.

[0184] For example, the number of battery modules is set to 20, and the preset convergence threshold is 0.5℃. The temperature difference between the inlet and outlet water of each module is collected, and the average temperature difference is calculated to be 8.2℃. According to the formula, the thermal balance dispersion index C is 0.3℃, which is lower than the threshold of 0.5℃, and remains stable for 5 consecutive sampling cycles (2 seconds per cycle). The main control unit determines that the system has reached thermal balance and generates a high-level system thermal balance status indicator, indicating that the temperature field under dual-path independent operation has been uniformly distributed, providing a reliable basis for subsequently locking the final operating parameters.

[0185] S5.5: Combining the system thermal balance status indicator and the target operating condition charge / discharge rate requirement, lock the final operating frequency and outlet set temperature of the two liquid chillers, solidify the current dual-path independent operating parameter set into the standard operating configuration, so as to generate a dual-path independent operating target condition that eliminates the historical differences in pipeline heat exchange and meets the full power heat dissipation requirements.

[0186] The system receives the thermal balance status indicator and the target charge / discharge rate requirement data of the current energy storage system as the basic input parameters for operating condition locking.

[0187] Based on the mapping relationship between the target charge / discharge rate and the heat dissipation characteristics of the battery module, the reference value of the total coolant flow rate to meet the heat dissipation requirements is obtained by looking up the table, and the target volumetric flow rate of a single liquid cooler is calculated by combining the flow distribution coefficient in the dual-path independent operation mode.

[0188] Based on the characteristic curves of the liquid chiller pump unit, the target volumetric flow rate is converted into the corresponding motor operating frequency command using an inverse function model, generating the target speed setpoints for synchronization of the two liquid chillers. The formula is as follows:

[0189]

[0190] in, For the target operating frequency, It is the inverse function of pump flow rate and frequency. This is the baseline value for total coolant flow rate. This is the flow distribution coefficient.

[0191] Read the real-time feedback data from the inlet temperature sensors of each battery module, calculate the average inlet temperature difference between the two cooling circuits, and use it as the error input for temperature fine-tuning.

[0192] The proportional-integral control method is used to calculate the temperature difference and generate independent correction values ​​for the outlet set temperatures of the two liquid chillers to compensate for the thermal hysteresis effect caused by differences in pipeline length or heat exchange history.

[0193] The calculated target speed setpoint is integrated with the outlet temperature correction to form a standard operating configuration parameter set that includes both frequency and temperature dimensions.

[0194] Write the parameter set into the non-volatile memory of the main control unit, update the system operating mode flag, and complete the final switch from emergency reset state to full-power dual-channel independent operation state.

[0195] Through the above closed-loop calculation and parameter solidification process, the thermal balance state of the previous step is transformed into specific execution instructions and configuration data, thereby achieving the dual-path independent operation target condition that eliminates historical differences in pipeline heat exchange and meets the full-power heat dissipation requirements.

[0196] Step S6: Based on the dual-path independent operation target condition, verify the overall condition of the liquid chiller and generate a comprehensive verification report on system recovery to normal operation. Specifically, this includes:

[0197] S6.1: Obtain the mechanical travel switch feedback signal of each solenoid valve and the preset fully open and fully closed position threshold, perform logic level comparison processing on the mechanical travel switch feedback signal to generate a valve position status confirmation data set that includes the confirmation results of the fully open state of the isolation valve group and the confirmation results of the fully closed state of the switching valve group.

[0198] The main control unit reads the raw digital level signals of the Hall effect or reed mechanical limit switches configured on the isolation valves of the inlet and outlet water supply on the fault side and the switching valves on the bridge pipeline. The collected discrete level signals are mapped to Boolean state variables of the valve's physical position, where a high level indicates that the contact is closed, i.e., the valve has reached its limit position, and a low level indicates that the contact is open, i.e., the valve has not reached its limit position.

[0199] The valve position logic truth table, which is pre-stored in non-volatile memory, is invoked. This truth table defines the expected combination of level outputs of the limit switch when the isolation valve is fully open and the expected combination of level outputs of the limit switch when the switching valve is fully closed.

[0200] The matching degree of the real-time acquired limit switch level sequence is calculated by using bitwise XOR operation with the preset standard position level template. For isolation valve groups, if the real-time feedback level is completely consistent with the fully open position template, the valve is determined to be in the fully open ready state; for switching valve groups, if the real-time feedback level is completely consistent with the fully closed position template, the valve is determined to be in the fully closed cut-off state.

[0201] A time-based jitter filter is introduced to verify the consistency of the judgment results across multiple consecutive sampling periods. Only when the judgment result for a certain valve position remains constant and true within a preset stable time window is the final state flag of that valve position locked as valid, thus eliminating transient signal glitches caused by mechanical vibration.

[0202] The status flags of all solenoid valves involved in pipeline switching are aggregated to construct a structured valve position status confirmation dataset. This dataset clearly identifies whether the fault-side isolation valve has established a complete flow cross-section and whether the bridging switching valve has completely blocked bypass flow.

[0203] Through the above logical comparison and time-domain filtering, the fluid balance state of the previous step is transformed into determined mechanical valve position topology verification data, realizing the digital verification of the reliability of the pipeline physical connection and providing a solid physical foundation for subsequent temperature consistency verification.

[0204] For example, the system is configured with four isolation valves and two switching valves, each equipped with a normally open reed switch. The switch outputs a high level (1) when the isolation valve is fully open and when the switching valve is fully closed. The main controller samples signals at 10ms intervals, with a set stabilization time window of 500ms. If isolation valve 1 returns a high level (1) at 50 consecutive sampling points and matches the preset template, its state is marked as "fully open confirmed." If switching valve 1 returns a high level (1) at 50 consecutive sampling points, its state is marked as "fully closed confirmed." The final generated valve position confirmation data set shows that all six valves conform to the expected position logic, and a verification pass command is output.

[0205] S6.2: Based on the valve position status confirmed in the valve position status confirmation data set, collect the actual temperature values ​​of the coolant in the outlet pipes of the two sets of liquid chillers, and perform absolute value calculation on the difference between the actual temperature values ​​of the coolant in the outlet pipes of the two sets of liquid chillers to generate a quantitative index of liquid chiller outlet temperature deviation that characterizes the degree of dual-path thermal balance.

[0206] Based on the valve position status confirmation data set generated in step S6.1, the main control unit starts the dual-path thermal balance verification program after confirming that the isolation valve group is in the fully open position and the switching valve group is in the fully closed position.

[0207] The first high-precision temperature sensor deployed on the outlet pipe of liquid cooler 1 and the second high-precision temperature sensor deployed on the outlet pipe of liquid cooler 2 are invoked to synchronously collect the raw signal of the coolant outlet temperature at the current moment.

[0208] The first and second raw temperature signals are processed by moving average filtering to eliminate instantaneous jitter caused by fluid turbulence or high-frequency noise from the sensor, and to generate smoothed outlet temperature values ​​of liquid cooler 1 and liquid cooler 2.

[0209] Using an absolute difference calculation model, the deviation of the smoothed dual-channel outlet temperatures is quantified to construct a key index characterizing the thermodynamic consistency of the dual-channel system. The calculation formula is as follows:

[0210]

[0211] in, This is a quantitative indicator for the outlet temperature deviation of a liquid chiller. The temperature of the coolant in the outlet pipe of liquid chiller 1. This refers to the coolant temperature in the outlet pipe of the liquid cooler 2.

[0212] The calculated liquid cooler outlet temperature deviation quantification index is logically compared with the preset thermal balance tolerance threshold of 0.5℃. If the liquid cooler outlet temperature deviation quantification index is less than or equal to 0.5℃, it is determined that the consistency of the dual-channel coolant temperature meets the reset requirement, and a qualified liquid cooler outlet temperature deviation quantification index is generated.

[0213] By using the above absolute difference calculation and threshold comparison processing method, the normal valve position status of the previous step is transformed into a quantitative dual-path thermal balance index, which realizes accurate verification of the consistency of the system's thermal performance after fault recovery and ensures the stability of subsequent full-power operation.

[0214] S6.3: Using the liquid cooler outlet temperature deviation quantification index as the input benchmark, read the real-time temperature sensor data of each battery module inlet and outlet, and perform single-point temperature difference vector calculation on the real-time temperature sensor data of each battery module inlet and outlet to generate a battery module inlet and outlet temperature difference distribution sequence that reflects the heat exchange efficiency of a single battery module.

[0215] Read real-time sampling data from high-precision temperature sensors deployed at the inlet and outlet of each battery module, and construct a raw temperature dataset including timestamp alignment.

[0216] The raw temperature data is processed by moving average filtering to eliminate instantaneous high-frequency noise interference caused by fluid turbulence, generating smoothed inlet and outlet temperature sequences.

[0217] Based on the physical topology of the battery module, the smoothed inlet water temperature is paired and mapped with the corresponding outlet water temperature to ensure the logical correspondence of the single-point temperature difference calculation.

[0218] A single-point temperature difference vector operation model is used to calculate the temperature difference between the inlet and outlet of each battery module. The above temperature difference calculation is performed sequentially on all battery modules in the system to generate a sequence of temperature difference distribution between the inlet and outlet of the battery modules that includes the heat exchange efficiency characteristics of all modules.

[0219] By using a single-point temperature difference vector calculation method, the temperature sampling results from the previous step are transformed into a temperature difference distribution sequence data that reflects the local heat exchange efficiency, thereby enabling a refined and quantitative assessment of the expected technical effect of the thermal management status of each battery module.

[0220] For example, the system contains 40 battery modules with a sampling frequency of 1Hz. For module number 5, the filtered inlet water temperature is 25.0℃ and the outlet water temperature is 30.5℃. Substituting these values ​​into the formula, the temperature difference is calculated to be 5.5℃. The same operation is performed on all modules, generating a temperature difference distribution sequence of length 40 [5.2, 5.1, ..., 5.5, ...]. This sequence accurately reflects the heat dissipation uniformity of each module under the current operating conditions, providing precise data support for subsequent consistency verification.

[0221] S6.4: Based on the temperature difference distribution sequence of the battery module inlet and outlet, extract the typical temperature difference threshold range under historical normal operating conditions, and perform interval inclusion determination processing on each element in the temperature difference distribution sequence of the battery module inlet and outlet to generate a cell temperature difference fall-off compliance judgment flag that indicates whether the cell thermal management has returned to the normal range.

[0222] Obtain the temperature difference distribution sequence of the battery module inlet and outlet, which contains real-time inlet and outlet water temperature difference data of the battery module corresponding to each independent cooling circuit during the reset process.

[0223] The typical temperature difference threshold range under normal operating conditions is extracted from the system's historical operation database. This range is determined based on the statistical mean and standard deviation during long-term stable operation and serves as the benchmark interval for determining whether thermal management has returned to normal.

[0224] For each element in the temperature difference distribution sequence, an interval inclusion determination is performed, and the real-time monitored inlet and outlet water temperature difference values ​​are compared with the preset upper and lower limits of typical temperature difference thresholds.

[0225] If the real-time temperature difference of a battery module falls within the threshold range, the thermal management status of the module is marked as compliant; if it exceeds the threshold range, it is marked as deviating.

[0226] Iterate through the judgment results of all battery modules and count the proportion of modules that meet the criteria to the total number of modules.

[0227] When the proportion of modules meeting the requirements reaches a preset confidence threshold and maintains this proportion for multiple consecutive sampling cycles, a cell temperature difference fall compliance judgment flag is generated.

[0228] Through the above-mentioned interval determination and statistical verification processing method, the temperature difference distribution sequence of the previous step is transformed into a binary judgment flag that indicates whether the thermal management of the battery cell has returned to the normal range, thereby realizing the quantitative confirmation of the system reset completion and ensuring that the switch to full power mode is only allowed after the thermal balance is truly restored.

[0229] For example, a typical temperature difference threshold range is set to 2℃ to 5℃. If the temperature difference between the inlet and outlet water of a certain battery module is 3.5℃, falling within this range, it is considered compliant. If the temperature difference of 98% of the modules in the system falls between 2℃ and 5℃ and lasts for 10 seconds, a compliance judgment flag is generated as true, indicating that the system thermal balance has been restored, and subsequent mode switching operations are allowed.

[0230] S6.5: Integrate the valve position status confirmation data set, the liquid chiller outlet temperature deviation quantification index, and the battery cell temperature difference fall-off compliance judgment flag. Perform structured encapsulation and integrity verification processing on the integrated multi-source verification data to generate a comprehensive system recovery verification report that includes valve position status confirmation, temperature consistency verification, and battery cell temperature difference fall-off index.

[0231] Step S7: Based on the comprehensive verification report of the system recovery, perform a reset or rollback operation on the energy storage liquid cooling system, ultimately completing the pipeline switching and system reset after the energy storage liquid cooling system fault recovery. Specifically, this includes:

[0232] S7.1: Based on the valve position status confirmation results, temperature consistency verification data, and cell temperature difference drop index in the system recovery comprehensive verification report, the fault record flag bit stored in the main memory is logically cleared to generate a system clean status identifier without fault history residue, providing a reliable logical premise for subsequent working mode switching.

[0233] S7.2: Using the system clean status flag as an enabling condition, perform a mapping transformation operation on the system working mode flag from the single-machine emergency operation mode to the original configuration mode to generate a system full-power operation mode instruction that represents the formal establishment of the dual-path independent operation target condition, thereby realizing the automatic and seamless switching of the control strategy.

[0234] The system receives the system clean status flag as a logic enable signal and reads the preset original configuration mode parameter set from the main memory, including the rated speed of the dual liquid cooler, the standard valve position topology, and the target temperature threshold.

[0235] A snapshot backup of the execution state of the control strategy register currently in stand-alone emergency operation mode is performed, recording the frequency reduction coefficient and valve opening limit value in emergency mode, and generating safety rollback baseline data before mode switching.

[0236] Based on the validity verification result of the system cleanliness status identifier, the frequency upper limit lock command of the liquid chiller inverter driver is released, allowing the drive unit to receive the speed set value of the full power operating range.

[0237] The operating mode flag is transformed from a binary code representing fault-tolerant status to a standard operating condition code representing independent operation of the two paths, and the state machine jump pointer of the main control unit is updated.

[0238] A synchronous full-power start command is broadcast to the controllers of the two liquid chillers. The target frequency at the current moment is calculated based on the preset speed ramp-up curve to eliminate the risk of uneven compressor lubrication caused by long-term low-frequency operation.

[0239] Based on the updated operating mode flag, the thermal management request interface of the battery management system is reactivated, the charging and discharging power limit is restored to the rated maximum value, and the power clamping imposed due to insufficient cooling capacity redundancy is released.

[0240] By using a mode mapping transformation process, the system cleaning state of the previous step is converted into a full-power operation mode command, realizing an automated and seamless switch of the control strategy from emergency fault tolerance to normal dual-path independent operation.

[0241] S7.3: For real-time feedback signals during the execution of commands in the full-power operation mode of the system, parallel monitoring and logical judgment processing are performed on valve position feedback signal timeout events and pressure exceeding safety boundaries events to generate a system reset failure judgment conclusion containing abnormality type identification results, which serves as the direct basis for triggering the protection mechanism.

[0242] The system receives real-time feedback signals during the execution of commands for full-power operation mode, including the status signals of the mechanical limit switches of each solenoid valve and the pressure sensor sampling values ​​of key nodes in the liquid cooling pipeline.

[0243] The timeout detection logic is executed on the valve position feedback signal. The internal watchdog timer is started to record the elapsed time from the issuance of the command to the receipt of the acknowledgment signal. The elapsed time is then compared with the preset maximum response time threshold.

[0244] If the elapsed time exceeds the maximum response time threshold, it is determined to be a valve position feedback timeout event, and a valve position abnormality flag is generated to indicate that the solenoid valve with a specific number has a risk of jamming or communication failure.

[0245] Real-time pressure data of key nodes at the outlet of the liquid chiller and the bridge pipeline are collected synchronously. A pressure sequence within a sliding time window is constructed, and the difference between the maximum and minimum pressure values ​​within the window is calculated as the pressure fluctuation amplitude.

[0246] The pressure fluctuation amplitude is compared with the preset safety boundary threshold. If the pressure fluctuation amplitude exceeds the safety boundary threshold, it is determined to be a pressure overrun event, and a pressure abnormality flag is generated to indicate that there is a risk of blockage or leakage in the pipeline.

[0247] Perform a logical OR operation on the valve position abnormality flag and the pressure abnormality flag. If either flag is true, the system reset failure judgment logic is triggered, generating a system reset failure judgment conclusion containing the specific abnormality type code.

[0248] By monitoring valve position response time and pressure stability indicators in parallel, the real-time physical state is transformed into digital anomaly diagnosis results, enabling early fault identification and rapid triggering of protection mechanisms.

[0249] For example, the maximum response time threshold for the solenoid valve is set to 500ms, and the pressure safety boundary threshold is ±0.2MPa. During the reset process, if solenoid valve 3 does not return a fully open signal within 600ms after the command is issued, the watchdog timer determines that the timeout has occurred and sets the valve position abnormality flag. Simultaneously, if the liquid chiller outlet pressure is detected to fluctuate by 0.3MPa within 1 second, exceeding the ±0.2MPa threshold, a pressure abnormality flag is set. Upon detecting any abnormality flag, the main control unit immediately generates a reset failure conclusion, with the code pointing to either "valve 3 stuck" or "pipeline pressure oscillation," triggering the subsequent fallback protection process, significantly improving the system's safety and response speed under abnormal operating conditions.

[0250] S7.4: Based on the system reset failure determination conclusion, a forced reversal reset operation is performed on the opening control commands of all solenoid valves to restore all valve states to the preset opening combination in the bridging state, so as to generate a system safety bridging protection state that maintains the pre-balanced working condition of the coolant connection circuit and prevents the risk of fluid impact or flow interruption caused by switching interruption.

[0251] Receive the system reset failure judgment conclusion, parse the exception type identifier, and determine the execution priority of triggering the forced rollback reset operation.

[0252] The valve state mapping table is invoked to retrieve the target opening combination of each solenoid valve under the bridged protection state, and a reset control sequence containing the isolation valve fully closed command and the switching valve fully open command is generated.

[0253] An emergency shut-off drive is executed on the isolation valves for the inlet and outlet water on the fault side, reducing the valve opening at the maximum permissible rate to cut off the coolant supply path of the independent circuit on the fault side and prevent backflow impact.

[0254] Synchronously send a full-open drive signal to the switching valve on the bridge pipeline to eliminate the mechanical hysteresis of the valve core, quickly establish a connected circuit, and ensure that the coolant forms a low-impedance bypass between the main circuit and the backup circuit.

[0255] Real-time monitoring of pipeline pressure sensor data, calculation of pressure recovery slope, and verification of the effectiveness of establishing the pre-balanced operating condition of the connected loop.

[0256] If the pressure recovery slope is within the preset safe range, the system safety bridging protection state is confirmed to be complete, and the current valve position is locked.

[0257] Through the above-mentioned forced rollback reset operation, the abnormal state of the previous step is transformed into stable pre-balanced operating condition data of the connected loop, thereby achieving the expected technical effect of preventing fluid impact and flow interruption risks.

[0258] For example, when a feedback timeout is detected in the isolation valve, the main control unit immediately generates a reset control sequence. The faulty isolation valve is controlled to decrease from 100% opening to 0% within 2 seconds, while the bridging switching valve is controlled to increase from 0% opening to 100% within 1.5 seconds. The pipeline pressure is monitored to have fluctuated from 0.3 MPa and then stabilized at 0.25 MPa, with a pressure recovery slope of -0.05 MPa / s, within the safe range of -0.1 to 0.1 MPa / s. The system successfully enters the bridging protection state, avoiding the risk of pump dry running due to valve jamming and significantly improving system safety.

[0259] S7.5: Based on the triggering of the system's safety bridging protection state, the activation signal sending process is performed on the audible and visual alarm device drive circuit, and an abnormal event log data packet containing specific fault codes is generated to complete the final control closed loop of automatic reset or abnormal rollback protection and output traceable alarm information to the operation and maintenance end.

[0260] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

[0261] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The “multiple” mentioned in the embodiments of this application refers to two or more. A and / or B indicate three possibilities: A; B; and A and B.

[0262] The above description is merely an exemplary embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for pipeline switching and system reset after fault recovery of an energy storage liquid cooling system, characterized in that, Specifically, it includes: S1: Obtain the system reset command after the faulty liquid chiller is replaced, control the newly replaced liquid chiller to start synchronously at low speed with the currently running liquid chiller, keep the switching valve fully open and the isolation valve fully closed, and establish a pre-balanced working condition for the connected loop. S2: Based on the pre-balanced working condition of the connected loop, a continuous stability analysis of the pressure difference and temperature difference is performed to obtain the stability criterion of the pipeline state. S3: The stability criterion of the pipeline state is processed to obtain the action lag time window. The isolation valve and the switching valve are processed according to the action lag time window to obtain the seamless flow state. S4: During the seamless flow period, the status of the normally operating liquid cooler and the upstream of the faulty pipeline are monitored and compared in real time to obtain the safety verification result of the switching process; S5: After confirming that the isolation valve is fully open and the switching valve is fully closed based on the safety verification results of the switching process, operate the two liquid chillers to obtain the target operating condition of dual-path independent operation; S6: Based on the target operating conditions of dual-path independent operation, check the overall condition of the liquid chiller and generate a comprehensive verification report on system recovery to normal operation; S7: Based on the comprehensive verification report of the system recovery, perform a reset or rollback operation on the energy storage liquid cooling system, and finally complete the pipeline switching and system reset after the energy storage liquid cooling system fault recovery.

2. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 1, characterized in that, S1 specifically includes: After the faulty liquid chiller is replaced, the system reset command is obtained. The received system reset command is then validated and timed to generate a reset control reference signal. Based on the reset control reference signal, a synchronous frequency adjustment command is sent to the newly replaced liquid chiller and the currently running liquid chiller to execute the dual-machine low-frequency speed closed-loop coupling control method to generate a dual-machine synchronous low-speed operation state with the same rotation frequency characteristics. The initial valve position topology is obtained by logical judgment based on the dual-machine synchronous low-speed operation state. Utilizing the fluid driving force generated by the initial valve position topology and the synchronous low-speed operation of the two machines, the coolant in the outlet pipe of the newly replaced liquid chiller and the outlet pipe of the running liquid chiller are mixed and driven to generate a pre-balanced working condition of a connected loop containing the circulating driving force of the two liquid chillers.

3. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 2, characterized in that, The reset control reference signal includes the identification of the newly replaced liquid chiller and the target low-frequency speed setting value.

4. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 2, characterized in that, The process of obtaining the initial valve position topology based on logical judgment of the dual-machine synchronous low-speed operation state includes: Based on the dual-machine synchronous low-speed operation state, the current position feedback signals of the switching valve group and the isolation valve group of the fault side inlet and outlet water on the bridge pipeline are read, and the valve position deviation is logically judged to generate an initial valve position topology structure in which the switching valve group is in the fully open position and the isolation valve group is in the fully closed position.

5. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 1, characterized in that, S3 specifically includes: Based on the pipeline stability criterion, the isolation valves for the inlet and outlet water on the fault side are subjected to pulse width modulation processing to generate a slow opening drive signal for the isolation valve with an extremely low rate of change. The initial valve opening increment sequence is obtained based on the slow opening drive signal for the isolation valve. Using the initial valve opening increment sequence, the timing offset calculation is performed on the closing action of the switching valve on the bridge pipeline to generate a switching valve cooperative closing drive strategy, and the action lag time window is obtained based on the switching valve cooperative closing drive strategy. Based on the action lag time window, the real-time opening of the isolation valve for the inlet and outlet of the fault side and the switching valve of the bridge pipeline are subjected to linkage interpolation calculation to generate a valve coordinated motion trajectory curve that conforms to the logic of first opening and then closing, and a seamless flow state is obtained based on the valve coordinated motion trajectory curve.

6. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 1, characterized in that, S4 specifically includes: The real-time coolant pressure sampling sequence at the outlet of the normally operating liquid cooler and the instantaneous flow rate indication value of the upstream of the faulty pipeline are obtained. The real-time coolant pressure sampling sequence and the instantaneous flow rate indication value are processed respectively to obtain high signal-to-noise ratio pressure fluctuation characteristic data and synchronized flow status monitoring data. The pressure fluctuation characteristic data with high signal-to-noise ratio and the synchronized flow status monitoring data are calculated and compared to obtain the pressure safety boundary determination results and the flow continuity determination results. Based on the pressure safety boundary determination result and the flow continuity determination result, a multi-condition joint logic verification method is executed. If the pressure change rate derivative exceeds the pressure allowable bandwidth threshold or the absolute value of the flow deviation is lower than the normal flow threshold lower limit, an abnormal interruption mechanism is immediately triggered to generate a valve position freeze signal. If the multi-condition joint logic verification method confirms that the derivative of the pressure change rate is within the pressure allowable bandwidth threshold and the absolute value of the flow deviation is higher than the lower limit of the normal flow threshold, then the smooth transition allow flag is activated and a continue execution signal is generated. By integrating the status information of the valve position freeze signal or continue execution signal, and combining it with the current solenoid valve action timing record, the safety verification result of the switching process is obtained.

7. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 6, characterized in that, The process of processing the real-time coolant pressure sampling sequence and instantaneous flow rate indication values ​​respectively yields high signal-to-noise ratio pressure fluctuation characteristic data and synchronized flow status monitoring data, including: A sliding window filter is applied to the real-time coolant pressure sampling sequence to generate high signal-to-noise ratio pressure fluctuation characteristic data. At the same time, the instantaneous flow rate indication value is timestamped and calibrated to generate synchronized flow status monitoring data.

8. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 6, characterized in that, The calculation and comparison of high signal-to-noise ratio pressure fluctuation characteristic data and synchronized flow status monitoring data yields pressure safety boundary determination results and flow continuity determination results, including: Based on the high signal-to-noise ratio pressure fluctuation characteristic data and the synchronized flow status monitoring data, the derivative of the pressure change rate and the absolute value of the flow deviation at the current moment are calculated. The derivative of the pressure change rate is dynamically compared with the preset pressure allowable bandwidth threshold to generate a pressure safety boundary judgment result. The absolute value of the flow deviation is logically compared with the set lower limit of the normal flow threshold to generate a flow continuity judgment result.

9. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 6, characterized in that, The continued execution signal includes an instruction to continue the slow opening of the isolation valve and the coordinated closing of the switching valve in the next cycle.

10. The method for pipeline switching and system reset after fault recovery of the energy storage liquid cooling system according to claim 1, characterized in that, All isolation valves and switching valves are driven by stepper motors with closed-loop position feedback, and mechanical hysteresis is compensated using the PID method.

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