An outlet superheat adaptive control method for a battery direct cooling system and electronic equipment

Abstract

This invention discloses an adaptive control method and electronic device for outlet superheat in a battery direct cooling system, relating to the field of battery direct cooling systems. Based on the current superheat error and the current error change rate, this invention dynamically tunes the proportional coefficient, integral coefficient, and derivative coefficient through a piecewise linear function and a limiting function, enabling the PID control parameters to adaptively adjust in real time according to the superheat deviation and its changing trend. This overcomes the problem that existing fixed-parameter PID controllers are difficult to adapt to dynamic changes in operating conditions due to parameter fixation, effectively suppressing oscillations and response lag in the superheat control process, and improving the dynamic adjustment performance of the system.

Description

Technical Field

[0001] This invention relates to the field of battery direct cooling systems, and more particularly to an adaptive control method and electronic device for outlet superheat of battery direct cooling systems. Background Technology

[0002] As a key technology in the thermal management of new energy vehicles, the performance of the direct cooling system for power batteries directly affects the safety and range of the entire vehicle. In this system, the evaporator outlet superheat is a core control parameter for ensuring cooling efficiency and preventing refrigerant backflow and compressor liquid slugging damage. Too low a superheat can easily lead to compressor liquid slugging, while too high a superheat results in a significant decrease in cooling efficiency. However, in actual operating conditions, there is a strong coupling and nonlinear relationship between battery heat load, evaporation pressure, and electronic expansion valve opening, posing a significant challenge to the stable control of superheat.

[0003] Currently, the industry commonly uses fixed-parameter PID controllers to regulate superheat. This approach typically calculates superheat based solely on the real-time temperature and pressure at the evaporator outlet and generates control commands using preset fixed proportional, integral, and derivative coefficients. However, this static parameter strategy exhibits severe inadequacy in adapting to dynamically changing heat loads or evaporation pressure disturbances, easily leading to superheat oscillations, response lag, or significant static errors.

[0004] To improve control performance, some improvement schemes have introduced feedforward compensation mechanisms. However, these feedforward signals often rely on single heat load information, failing to effectively decouple the direct impact of evaporation pressure fluctuations on superheat. When system pressure changes abruptly, the saturation temperature also changes, leading to distortion of the calculated superheat value. Conventional control logic struggles to compensate quickly, resulting in sudden increases or decreases in superheat and a high risk of liquid return. Furthermore, existing technologies generally lack the ability to predict and proactively intervene in rapid declines in superheat, often only passively implementing protective measures after the superheat falls below a safe threshold, failing to fundamentally suppress the risk of liquid return.

[0005] The aforementioned control deficiencies are particularly prominent during the system development and verification phases. Although mainstream thermofluid simulation software such as STAR-CCM+ can achieve high-precision three-dimensional transient simulations of direct-cooling systems, existing control schemes, lacking safety constraints on valve opening (such as upper and lower limits and rate limits), are prone to computational divergence during simulations due to the generation of extreme or discontinuous control commands, resulting in unstable operation. Furthermore, their fixed PID parameters, undecoupled pressure disturbances, and lack of anti-sudden drop protection mechanisms lead to distorted or divergent control behavior in simulations, making it difficult to effectively develop and verify a stable and robust superheat control strategy through simulation, thus hindering subsequent engineering development. Summary of the Invention

[0006] To overcome the problems of fixed superheat control parameters, strong undecoupled pressure-superheat coupling, response lag, sudden drop in control, and difficulty in effectively developing stable and robust superheat control strategies through simulation in existing technologies, this invention proposes an adaptive superheat control method for the outlet of a battery direct cooling system, including: Real-time acquisition of evaporator operating data; the evaporator operating data includes evaporator outlet temperature and evaporator outlet pressure; Calculate the current actual superheat based on the evaporator outlet temperature and the refrigerant saturation temperature determined by the evaporator outlet pressure. The current superheat error is calculated based on the actual superheat and the target superheat, and the rate of change of this error is calculated based on the superheat error between the current and the previous control cycle as the current error rate of change. Based on the current superheat error and the current error change rate, the proportional coefficient, integral coefficient and differential coefficient are dynamically tuned by a piecewise linear function and a limiting function. Based on the tuned proportional coefficient, integral coefficient, and derivative coefficient, as well as the current superheat error, the PID control output for the current control cycle is generated. Based on the PID control output, the target opening value of the electronic expansion valve in the current control cycle is generated.

[0007] Furthermore, the evaporator operating data also includes the total heat exchange of the evaporator and the average pressure inside the evaporator; The step of generating the target opening value of the electronic expansion valve in the current control cycle based on the PID control output includes: Based on the total heat exchange of the evaporator and the average pressure inside the evaporator, a heat load feedforward channel and an evaporation pressure feedforward channel are constructed respectively to generate the corresponding heat load feedforward quantity and evaporation pressure feedforward quantity, and the two are superimposed to obtain the total feedforward compensation quantity. The PID control output is superimposed with the total feedforward compensation to obtain the basic control quantity; depending on whether the safety protection condition is triggered, the basic control quantity is selectively superimposed with the corresponding protection compensation quantity to obtain the total control quantity; the target opening value of the electronic expansion valve in the current control cycle is generated based on the total control quantity.

[0008] Furthermore, the dynamic tuning of the proportional coefficient, integral coefficient, and differential coefficient based on the current superheat error and the current error change rate, using a piecewise linear function and a limiting function, includes: Based on the current superheat error and the current error change rate, generate the proportional scaling factor, integral scaling factor and differential scaling factor respectively; The scaling factor is determined based on the current superheat error and the current error change rate, the integral scaling factor is determined based on the current superheat error, and the differential scaling factor is determined based on the current error change rate. The preset basic scaling factor, basic integral factor, and basic differential factor are multiplied by their respective scaling factors, and then subjected to a scaling factor limit to obtain the updated scaling factor, integral factor, and differential factor.

[0009] Furthermore, the step of generating the PID control output for the current control cycle based on the tuned proportional coefficient, integral coefficient, and derivative coefficient, and the current superheat error, includes: Based on the current superheat error, the adjusted proportional coefficient, integral coefficient, and differential coefficient, calculate the proportional term, integral term, and differential term respectively; The calculation of the integral term includes: Based on the current superheat error, the integral term is recursively accumulated over time to obtain the updated integral term; Apply upper and lower threshold limits to the updated integral term. When the integral term exceeds the threshold range, clamp it to the corresponding upper or lower threshold.

[0010] Furthermore, the generation of the corresponding heat load feedforward and evaporation pressure feedforward includes: Multiply the total heat exchange of the evaporator by the preset heat load feedforward coefficient to obtain the heat load feedforward amount; The pressure deviation is obtained by subtracting the average pressure inside the evaporator from the rated evaporation pressure, and then multiplying the pressure deviation by a preset evaporation pressure feedforward coefficient to obtain the evaporation pressure feedforward amount.

[0011] Furthermore, the step of selectively superimposing the basic control quantity with the corresponding protection compensation quantity based on whether a safety protection condition is triggered to obtain the total control quantity includes: Based on the current actual superheat and the current error rate of change, determine whether the preset safety protection conditions are met. If at least one safety protection condition is triggered, the corresponding compensation amount is generated according to each triggered safety protection condition, and all compensation amounts are linearly superimposed to obtain the total protection compensation amount. The total protection compensation amount is added to the basic control amount to obtain the total control amount; If no safety protection conditions are triggered, the total control quantity equals the basic control quantity.

[0012] Furthermore, the security protection conditions include at least one of the following: Superheat determination criteria: The current actual superheat is lower than the first safety threshold; Change rate determination criteria: The current error change rate is lower than the second safety threshold; Specifically, when the superheat determination condition is triggered, a first fixed negative opening compensation amount is generated; when the rate of change determination condition is triggered, a second fixed negative opening compensation amount is generated.

[0013] Further, the generation of the target opening value of the electronic expansion valve in the current control cycle based on the total control quantity includes: The opening change rate is limited for the total control quantity, and the limited result is used as the single-step control quantity, where: If the total control quantity is greater than the opening value of the previous control cycle, it is determined to be a valve opening command, and the difference between the total control quantity and the opening value of the previous control cycle is limited to not exceeding the first preset opening change threshold, so as to obtain the single-step control quantity. If the total control quantity is less than the opening value of the previous control cycle, it is determined to be a valve closing command, and the absolute value of the difference between the total control quantity and the opening value of the previous control cycle is limited to not exceeding the second preset opening change threshold, so as to obtain the single-step control quantity. The current opening of the electronic expansion valve is added to the single-step control quantity to obtain the preliminary target opening. An amplitude limit is applied to the preliminary target opening to ensure that it is not lower than the preset minimum opening value and does not exceed the preset maximum opening value, thus obtaining the target opening value of the electronic expansion valve. Wherein, the second preset opening change threshold is greater than the first preset opening change threshold.

[0014] Furthermore, obtaining the rated evaporation pressure includes: Fix the opening of the electronic expansion valve to a preset intermediate opening and run the system; During system operation, the average pressure inside the evaporator, the outlet temperature of the evaporator, and the total heat exchange of the evaporator are continuously monitored. When the fluctuation range of the monitored average pressure inside the evaporator, the outlet temperature of the evaporator, and the total heat exchange of the evaporator in multiple consecutive control cycles does not exceed their respective preset steady-state thresholds, the system is determined to have reached steady state. The average pressure inside the evaporator under steady-state conditions is read as the rated evaporation pressure.

[0015] To address the aforementioned problems, another aspect of this invention provides an electronic device, including: a processor and a memory storing a program, the program including instructions that, when executed by the processor, cause the processor to perform the aforementioned adaptive control method for outlet superheat of a battery direct cooling system.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Based on the current superheat error and the current error change rate, the present invention dynamically tunes the proportional coefficient, integral coefficient and derivative coefficient through piecewise linear function and limit function, so that the PID control parameters can be adaptively adjusted in real time according to the superheat deviation and its changing trend. This overcomes the problem that the existing fixed parameter PID controller is difficult to adapt to the dynamic changes of the working condition due to the solidification of parameters, effectively suppresses the oscillation and response lag in the superheat control process, and improves the dynamic adjustment performance of the system.

[0017] (2) This invention constructs a heat load feedforward channel based on the total heat exchange of the evaporator and an evaporation pressure feedforward channel based on the average pressure inside the evaporator. The two are superimposed to form a total feedforward compensation amount, which is directly superimposed to the PID control output. This allows for open-loop compensation of known external disturbances without relying on superheat feedback deviation. This mechanism effectively weakens the coupling interference between heat load changes and evaporation pressure fluctuations on the superheat control process. In particular, it addresses the problem of evaporation pressure sudden changes leading to saturation temperature changes and thus causing superheat calculation distortion. Since the evaporation pressure feedforward channel directly uses real-time pressure signals to generate compensation amounts, it can simultaneously provide offsetting valve opening adjustment when the system experiences false jumps in superheat due to recalculation of saturation temperature. This avoids malfunction of the electronic expansion valve caused by misjudgment of superheat and significantly reduces the risk of compressor liquid return.

[0018] (3) The present invention determines whether the safety protection condition is triggered based on the current actual superheat and the current error change rate, and generates the corresponding negative opening compensation amount when the superheat is lower than the first safety threshold or the error change rate is lower than the second safety threshold, thereby realizing the proactive prediction and intervention of the rapid decline trend of superheat. Compared with the prior art, which only provides passive protection after the superheat exceeds the limit, the present invention can close the valve in advance when the superheat has not yet fallen below the safety threshold but has shown a dangerous downward trend, thereby fundamentally suppressing the risk of compressor liquid slugging.

[0019] (4) The present invention limits the opening change rate and amplitude of the total control quantity, including limiting the single-step control quantity to not exceed the preset opening change threshold, and constraining the target opening value within the preset minimum and maximum opening value range, effectively avoiding extreme jumps or discontinuous actions of the electronic expansion valve command; this safety constraint mechanism solves the problem of simulation calculation divergence caused by the lack of valve opening safety constraints, so that the control strategy can run stably in high-precision transient simulation platforms such as STAR-CCM+, supporting reliable development and verification. Attached Figure Description

[0020] Figure 1 A flowchart of an adaptive control method for outlet superheat in a battery direct cooling system; Figure 2 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0021] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0022] To overcome the problems in existing technologies, such as fixed superheat control parameters, strong undecoupled pressure-superheat coupling, response lag, sudden drop and runaway, and the difficulty in effectively developing stable and robust superheat control strategies through simulation, such as... Figure 1 As shown, this invention proposes an adaptive control method for outlet superheat of a battery direct cooling system, comprising: Real-time acquisition of evaporator operating data; the evaporator operating data includes evaporator outlet temperature and evaporator outlet pressure; The evaporator operating data also includes the total heat exchange of the evaporator and the average pressure inside the evaporator; Calculate the current actual superheat based on the evaporator outlet temperature and the refrigerant saturation temperature determined by the evaporator outlet pressure. Current actual superheat (SH) refers to the difference between the actual temperature of the refrigerant at the evaporator outlet and its corresponding saturation temperature at the current pressure.

[0023] The specific calculation formula is as follows: ; in: It is the evaporator outlet temperature measured by a temperature sensor; It is the evaporator outlet pressure; It is based on this pressure The corresponding saturation temperature obtained by looking up the refrigerant property table is the phase transition temperature at which the refrigerant changes from a liquid to a gaseous state at this pressure. Specifically, it is obtained by querying a pre-built pressure-saturation temperature interpolation relationship based on the refrigerant property table. This mapping relationship ensures high calculation accuracy at any outlet pressure.

[0024] Superheat reflects whether the refrigerant at the evaporator outlet has been completely vaporized. If SH > 0, it means that the refrigerant has been completely converted into gas and further heated; if SH ≈ 0 or is negative, there may be unevaporated liquid refrigerant, which may cause liquid slugging in the compressor.

[0025] In this embodiment, superheat error is defined. for: ; in, The target superheat (unit: °C) preset for the system. This represents the actual superheat at the evaporator outlet (unit: °C). Correspondingly, the error variation rate... Represents a unit of time The change in temperature (unit: ℃ / s).

[0026] It should be noted that the average pressure inside the evaporator is obtained by setting a monitoring surface in the refrigerant flow channel of the evaporator and calculating the pressure on the monitoring surface by area averaging; the total heat exchange of the evaporator is obtained by calculating the heat flux density on all heat exchange surfaces in contact with the battery cooling plate by area integral.

[0027] In the first control cycle after control is initiated, the error rate of change is initialized to zero due to the lack of overheating error from the previous control cycle. From the second control cycle onwards, the error rate of change is calculated based on the error value between the current control cycle and the previous control cycle.

[0028] The current superheat error is calculated based on the actual superheat and the target superheat, and the rate of change of this error is calculated based on the superheat error between the current and the previous control cycle as the current error rate of change. Based on the current superheat error and the current error change rate, the proportional coefficient, integral coefficient and differential coefficient are dynamically tuned by a piecewise linear function and a limiting function. The method involves dynamically adjusting the proportional coefficient, integral coefficient, and differential coefficient based on the current superheat error and the current error change rate, using a piecewise linear function and a limiting function; including: Based on the current superheat error and the current error change rate, generate the proportional scaling factor, integral scaling factor and differential scaling factor respectively; The scaling factor is determined based on the current superheat error and the current error change rate, the integral scaling factor is determined based on the current superheat error, and the differential scaling factor is determined based on the current error change rate. The preset basic scaling factor, basic integral factor, and basic differential factor are multiplied by their respective scaling factors, and then subjected to a scaling factor limit to obtain the updated scaling factor, integral factor, and differential factor.

[0029] Specifically: 1. Preset parameters A set of basic PID parameters and corresponding parameter adjustment boundaries need to be pre-defined, specifically including: Basic proportional coefficient ( ), basic integral coefficient ( ), fundamental differential coefficients ( These are the baseline control parameters of the system under steady-state or small-disturbance conditions.

[0030] Parameter upper limit threshold: Scale coefficient upper limit threshold ( ), upper limit threshold of integral coefficient ( ), upper limit threshold of differential coefficients ( Setting an upper limit is to prevent parameters from being excessively amplified under large disturbances, thereby causing system oscillations or even instability.

[0031] The final proportionality coefficient ( ), integral coefficient ( ) and differential coefficients ( The system will be constrained within its reasonable range by limiting functions to ensure stable operation.

[0032] 2. Generation of dynamic scaling factor The key to this invention lies in based on real-time operating conditions (from...) and (Characteristics) Three independent scaling factors are dynamically generated to adjust the base PID parameters. The generation of these three scaling factors all adopts a "normalization-limiting-overlay" structure, as detailed below: 2.1 Scaling Factor Calculated in the following way: ; in, , The normalization constant is used to normalize physical quantities with different dimensions. and Convert to dimensionless or uniform order of magnitude numerical values; , This is the maximum gain factor, used to limit the maximum contribution of the error term and the error rate of change term to the scaling factor, respectively. Represents the amplitude limiting function, when Time output , Time output Otherwise output .

[0033] 2.2 Integral Scaling Factor Calculated in the following way: ; in, Let be the normalization constant for the integral term. This represents the maximum gain factor for integral scaling; the other symbols have the same meaning as above.

[0034] 2.3 Differential scaling factor Calculated in the following way: ; in, The normalization constant for the differential term, This represents the maximum gain factor for differential scaling; the other symbols have the same meaning as above.

[0035] In this embodiment: = 5、 = 2、 = 2、 = 2; = 5、 = 2; = 2、 = 2; Basic proportional coefficient Basic integral coefficient Fundamental differential coefficients ; Upper limit of proportional coefficient threshold Upper limit threshold of integral coefficient Upper limit threshold of differential coefficients .

[0036] 3. Determination of final PID parameters After obtaining the three dynamic scaling factors mentioned above, the preliminary dynamic PID parameters can be calculated, and final boundary constraints can be applied to them to obtain the proportional coefficient actually used in the controller. ), integral coefficient ( ) and differential coefficients ( The calculation process is as follows: proportionality coefficient Determined as: ; Integral coefficient Determined as: ; Differential coefficients Determined as: ; in, , , These represent the lower limit thresholds of the parameters corresponding to the proportional coefficient, integral coefficient, and derivative coefficient, respectively. All limiting operations ensure that the final parameters fall within the preset safe and effective range to prevent system instability caused by parameter mutations.

[0037] 4. The physical meaning of control logic When the actual overheat Below target superheat hour( ,in ), and All terms are set to 0, making and A value of 1 means that the proportional and integral actions are not enhanced, which is equivalent to reducing the adjustment intensity. In this state, the controller output is mainly determined by the base coefficient. Since the system adopts the reaction control logic, the negative superheat error (e<0) naturally drives the electronic expansion valve to close, reducing the refrigerant flow and allowing the superheat to recover. At the same time, it avoids the risk of system oscillation or liquid carryover at the evaporator outlet caused by over-adjustment.

[0038] When the overheating shows a rapid downward trend, and hour, and The term also takes the value 0, making and The value is 1, meaning that the proportional and derivative actions are not enhanced. If the superheat continues to decrease and reaches the safety threshold, the safety protection conditions (superheat determination condition and / or rate of change determination condition) will be activated, superimposed with a fixed negative opening compensation amount, forcibly closing the electronic expansion valve to ensure the compressor's safety.

[0039] When the popularity shows a rapid upward trend, and hour, and The item is activated, making and A value greater than 1 enhances the proportional and derivative effects. Based on this, the controller opens the electronic expansion valve earlier, increasing refrigerant flow, suppressing abnormal superheat, and preventing insufficient heat exchange in the evaporator.

[0040] In summary, this invention, through the aforementioned dynamic tuning mechanism, intelligently adjusts the control intensity under different operating conditions: maintaining robust control and relying on safety protection when the superheat is low or rapidly decreasing, and actively enhancing the response when the superheat is high or rapidly increasing, thereby improving the system's adaptability and control accuracy while ensuring safety.

[0041] In this embodiment: Opening the electronic expansion valve increases refrigerant flow rate, evaporator outlet temperature decreases, and superheat decreases. Closing the electronic expansion valve reduces refrigerant flow, increases evaporator outlet temperature, and increases superheat.

[0042] This invention employs a reaction control strategy, namely, superheat error When the value is negative, the controller output is negative, causing the electronic expansion valve to close slightly. When the time is right, it causes the valve to open wider.

[0043] Based on the tuned proportional coefficient, integral coefficient, and derivative coefficient, as well as the current superheat error, the PID control output for the current control cycle is generated. The process of generating the PID control output for the current control cycle based on the tuned proportional coefficient, integral coefficient, derivative coefficient, and current superheat error includes: Based on the current superheat error, the adjusted proportional coefficient, integral coefficient, and differential coefficient, calculate the proportional term, integral term, and differential term respectively; Specifically, the proportional term is obtained by multiplying the current superheat error by the tuned proportional coefficient, reflecting the immediate impact of the current deviation on the control output; the integral term is initially composed of the current superheat error multiplied by the integral coefficient, and is continuously updated over time; the derivative term is obtained by dividing the difference between the current superheat error and the error of the previous cycle by the control cycle (i.e., the error change rate), and then multiplying by the derivative coefficient, and is used to predict the deviation trend and suppress overshoot.

[0044] The calculation of the integral term includes: Based on the current superheat error, the integral term is recursively accumulated over time to obtain the updated integral term; An upper and lower threshold limit is applied to the updated integral term. When the integral term exceeds this threshold range, it is clamped to the corresponding upper or lower threshold. The clamping limit is used to prevent integral saturation due to the accumulation of errors over a long period of time.

[0045] In this embodiment, the integral term is updated using a time-series recursive accumulation method. Specifically, the current integral term is equal to the integral term of the previous control cycle plus the product of the current superheat error and the control cycle. This mechanism can continuously accumulate historical errors, effectively eliminate static deviations in the steady state of the system, and thus ensure that the superheat at the evaporator outlet accurately converges and is maintained near the set value under stable operating conditions.

[0046] Based on the PID control output, the target opening value of the electronic expansion valve in the current control cycle is generated.

[0047] The step of generating the target opening value of the electronic expansion valve in the current control cycle based on the PID control output includes: Based on the total heat exchange of the evaporator and the average pressure inside the evaporator, a heat load feedforward channel and an evaporation pressure feedforward channel are constructed respectively to generate the corresponding heat load feedforward quantity and evaporation pressure feedforward quantity, and the two are superimposed to obtain the total feedforward compensation quantity. The generation of the corresponding heat load feedforward and evaporation pressure feedforward includes: Multiply the total heat exchange of the evaporator by the preset heat load feedforward coefficient to obtain the heat load feedforward amount; The pressure deviation is obtained by subtracting the average pressure inside the evaporator from the rated evaporation pressure, and then multiplying the pressure deviation by a preset evaporation pressure feedforward coefficient to obtain the evaporation pressure feedforward amount.

[0048] Specifically: This invention calculates the heat load feedforward separately. , with evaporation pressure feedforward ,in, For heat load feedforward coefficient, This is the feedforward coefficient for evaporation pressure. Rated evaporation pressure, This indicates the average pressure inside the evaporator. This indicates the total heat exchange of the evaporator; The total feedforward compensation is obtained by superimposing the two: ; Subsequently, the PID control output of the current control cycle will be... and By superimposing these values, we obtain the basic control quantity: ; Finally, based on the safety protection conditions, it is determined whether to introduce a protection compensation quantity, and the total control quantity is generated. Based on this, the target opening value of the electronic expansion valve in the current control cycle is determined.

[0049] The key point is that the calculation of the actual superheat SH is based on the evaporator outlet pressure. , while evaporation pressure feedforward The calculation is based on the average pressure inside the evaporator ( During system operation, when operating conditions change abruptly (such as rapid changes in heat load or compressor speed), the average pressure inside the evaporator... With evaporator outlet pressure The trends and magnitudes of these changes are highly correlated. Therefore, when When a step change occurs, it is usually accompanied by The synchronous changes, which in turn lead to Sudden changes cause numerical fluctuations in the actual superheat SH even without a change in the actual thermodynamic state; simultaneously... because The changes in these quantities will synchronously produce corresponding increments or decreases. Because... and When superimposed on the basic control quantity within the same control cycle, the two have a logically inverse relationship on the electronic expansion valve opening command—that is, when... Elevation (usually accompanied by) When the increase causes a decrease in the calculated actual superheat SH value (tending towards triggering valve closing action), Increasing the SH value increases the basic control input, thus partially offsetting the valve-closing tendency of the PID controller caused by the decrease in SH; conversely, decreasing it also reduces the SH value. This mechanism enables the control command to inherently suppress fluctuations in the actual superheat value caused solely by pressure disturbances, allowing it to respond without waiting for the feedback deviation to accumulate.

[0050] This invention constructs a heat load feedforward channel based on the total heat exchange of the evaporator and an evaporation pressure feedforward channel based on the average pressure inside the evaporator. These two channels are then superimposed to form a total feedforward compensation, which is directly added to the PID control output. This allows for open-loop compensation of known external disturbances without relying on superheat feedback deviations. This mechanism effectively reduces the coupling interference between heat load changes and evaporation pressure fluctuations on the superheat control process. Particularly addressing the problem of distorted superheat calculations caused by sudden changes in evaporation pressure leading to changes in saturation temperature, the evaporation pressure feedforward channel directly utilizes real-time pressure signals to generate the compensation. This allows for simultaneous counteracting valve opening adjustments when the system experiences false jumps in superheat due to saturation temperature recalculation, preventing malfunctions of the electronic expansion valve caused by misjudgments of superheat and significantly reducing the risk of compressor liquid return.

[0051] Obtaining the rated evaporation pressure includes: Fix the opening of the electronic expansion valve to a preset intermediate opening and run the system; During system operation, the average pressure inside the evaporator, the outlet temperature of the evaporator, and the total heat exchange of the evaporator are continuously monitored. When the fluctuation range of the monitored average pressure inside the evaporator, the outlet temperature of the evaporator, and the total heat exchange of the evaporator in multiple consecutive control cycles does not exceed their respective preset steady-state thresholds, the system is determined to have reached steady state. The average pressure inside the evaporator under steady-state conditions is read as the rated evaporation pressure.

[0052] In one embodiment, the rated evaporation pressure is obtained by: In a simulation environment (such as the STAR-CCM+ platform), the opening of the electronic expansion valve is fixed at a preset intermediate opening of 50%. The simulation is run and the average pressure inside the evaporator, the outlet temperature, and the total heat exchange are monitored. When the fluctuations of the above parameters in several consecutive control cycles (10 to 20 control cycles) do not exceed their respective preset steady-state thresholds, the system is determined to have reached steady state. At this time, the average pressure inside the evaporator is the rated evaporation pressure.

[0053] In another embodiment, during the initialization phase of the vehicle thermal management controller, the electronic expansion valve is controlled to maintain the same preset intermediate opening, and the corresponding parameters are collected in real time through the pressure sensor, temperature sensor, and heat exchange calculated by the refrigerant flow and temperature difference. When the change of each parameter for multiple consecutive cycles is less than the steady-state threshold, it is determined that the steady-state condition has been entered, and the current average pressure inside the evaporator is taken as the rated evaporation pressure.

[0054] The PID control output is superimposed with the total feedforward compensation to obtain the basic control quantity; depending on whether the safety protection condition is triggered, the basic control quantity is selectively superimposed with the corresponding protection compensation quantity to obtain the total control quantity; the target opening value of the electronic expansion valve in the current control cycle is generated based on the total control quantity.

[0055] The step of selectively superimposing the basic control quantity with the corresponding protection compensation quantity based on whether a safety protection condition is triggered to obtain the total control quantity includes: Based on the current actual superheat and the current error rate of change, determine whether the preset safety protection conditions are met. If at least one safety protection condition is triggered, the corresponding compensation amount is generated according to each triggered safety protection condition, and all compensation amounts are linearly superimposed to obtain the total protection compensation amount. The security protection conditions include at least one of the following: Superheat determination criteria: The current actual superheat is lower than the first safety threshold; Change rate determination criteria: The current error change rate is lower than the second safety threshold; Specifically, when the superheat determination condition is triggered, a first fixed negative opening compensation amount is generated; when the rate of change determination condition is triggered, a second fixed negative opening compensation amount is generated.

[0056] The total protection compensation amount is added to the basic control amount to obtain the total control amount; If no safety protection conditions are triggered, the total control quantity equals the basic control quantity.

[0057] In one specific implementation, the first safety threshold is 1℃, the second safety threshold is -2℃ / s; the first fixed negative opening compensation amount is -5%, and the second fixed negative opening compensation amount is -5%.

[0058] This invention determines whether a safety protection condition is triggered based on the current actual superheat and the current error change rate. When the superheat is lower than the first safety threshold or the error change rate is lower than the second safety threshold, it generates a corresponding negative opening compensation amount, realizing proactive prediction and intervention of the rapid decline trend of superheat. Compared with the prior art, which only passively protects after the superheat exceeds the limit, this invention can close the valve in advance when the superheat has not yet fallen below the safety threshold but has shown a dangerous downward trend, fundamentally suppressing the risk of compressor liquid slugging.

[0059] The generation of the target opening degree of the electronic expansion valve in the current control cycle based on the total control quantity includes: The total control quantity (as the initial opening command) is subject to an opening change rate limit (specifically: the total control quantity is compared with the valve opening of the previous control cycle, the difference is calculated as the initial opening change, and the opening change rate is limited). The limited result is used as the single-step control quantity (representing the opening adjustment amount for a single control cycle), where: If the total control quantity is greater than the opening value of the previous control cycle, it is determined to be a valve opening command, and the initial opening change (the difference between the total control quantity and the opening value of the previous control cycle) is limited to not exceeding the first preset opening change threshold, thus obtaining the single-step control quantity; If the total control quantity is less than the opening value of the previous control cycle, it is determined to be a valve closing command, and the absolute value of the initial opening change is limited to not exceeding the second preset opening change threshold to obtain the single-step control quantity. The current electronic expansion valve opening is added to the single-step control quantity to obtain the preliminary target opening. An amplitude limit is applied to the preliminary target opening to ensure that it is not lower than the preset minimum opening value (10%) and does not exceed the preset maximum opening value (85%), thus obtaining the target opening value of the electronic expansion valve. Wherein, the second preset opening change threshold (5%) is greater than the first preset opening change threshold (1%).

[0060] This embodiment employs a slow-opening, fast-closing constraint on valve opening variation: the maximum single-step valve opening is no more than 1%, while the maximum valve closing is 5%. This design stems from safety considerations—when the superheat is low (e<0) or drops rapidly, although a safety feature is used to prevent this, the valve cannot open at all. and The value is set to 1 to avoid the controller over-enhancing its regulation, but it still allows the controller to quickly close the valve (up to 5%) in a single step to promptly prevent the risk of liquid refrigerant entering the compressor; while at higher superheat levels, even... and Enhanced to improve response speed, valve opening action is still strictly limited to within 1% of the rated flow to prevent sudden increases in refrigerant flow from causing severe overheating fluctuations. This layered control architecture, characterized by "conservative decision-making and decisive execution," effectively balances system safety and dynamic performance.

[0061] This invention limits the rate of change and amplitude of the total control quantity, including limiting the single-step control quantity to not exceed a preset opening change threshold, and constraining the target opening value within a preset minimum and maximum opening value range. This effectively avoids extreme jumps or discontinuous actions in the electronic expansion valve command. This safety constraint mechanism solves the problem of simulation calculation divergence caused by the lack of valve opening safety constraints, enabling the control strategy to run stably in high-precision transient simulation platforms such as STAR-CCM+, supporting reliable development and verification.

[0062] The method of this invention is applicable to both simulation and real operating environments. In the simulation environment, the evaporator operating data (such as outlet superheat, total heat exchange, internal average pressure, etc.) is calculated and generated by the system model, while in the real environment, it is collected in real time by sensors. The only difference between the two is the data source method, and the control logic and algorithm flow are completely consistent.

[0063] Based on the current superheat error and the current error change rate, this invention dynamically tunes the proportional coefficient, integral coefficient, and derivative coefficient through piecewise linear functions and limiting functions, enabling the PID control parameters to adaptively adjust in real time according to the superheat deviation and its changing trend. This overcomes the problem that existing fixed-parameter PID controllers are difficult to adapt to dynamic changes in operating conditions due to parameter fixation, effectively suppresses oscillations and response lags in the superheat control process, and improves the dynamic adjustment performance of the system.

[0064] This invention also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, which, when executed by the at least one processor, causes the electronic device to perform the method of this invention.

[0065] The present invention also provides a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of the present invention.

[0066] This invention also provides a computer program product, including a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of this invention.

[0067] refer to Figure 2 The present invention will now describe a structural block diagram of an electronic device that can serve as a server or client in embodiments of the present invention, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0068] like Figure 2As shown, the electronic device includes a computing unit 401, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 402 or a computer program loaded from a storage unit 408 into a random access memory (RAM) 403. The RAM 403 may also store various programs and data required for the operation of the electronic device. The computing unit 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0069] Multiple components in the electronic device are connected to I / O interface 405, including: input unit 406, output unit 407, storage unit 408, and communication unit 409. Input unit 406 can be any type of device capable of inputting information into the electronic device. Input unit 406 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of the electronic device. Output unit 407 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 408 may include, but is not limited to, disks and optical discs. Communication unit 409 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers, and / or chipsets, such as Bluetooth devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0070] The computing unit 401 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, CPUs, graphics processing units (GPUs), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. The computing unit 401 performs the methods and processes described above. For example, in some embodiments, the method embodiments of the present invention may be implemented as a computer program tangibly contained in a machine-readable medium, such as storage unit 408. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via ROM 402 and / or communication unit 409. In some embodiments, the computing unit 401 may be configured to perform the methods described above by any other suitable means (e.g., by means of firmware).

[0071] Computer programs for implementing the methods of embodiments of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0072] In the context of embodiments of the present invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0073] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the attached figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, descriptions involving "first," "second," or "a" in the present invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. In the description of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly defined. In the present invention, unless otherwise explicitly specified and defined, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. For those skilled in the art, the specific meanings of the above terms in this invention can be understood according to the specific circumstances. Furthermore, the technical solutions of the various embodiments of this invention can be combined with each other, but only on the basis that those skilled in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. An adaptive control method for outlet superheat of a battery direct cooling system, characterized in that, include: Real-time acquisition of evaporator operating data; The evaporator operating data includes the evaporator outlet temperature and the evaporator outlet pressure; Calculate the current actual superheat based on the evaporator outlet temperature and the refrigerant saturation temperature determined by the evaporator outlet pressure. The current superheat error is calculated based on the actual superheat and the target superheat, and the rate of change of this error is calculated based on the superheat error between the current and the previous control cycle as the current error rate of change. Based on the current superheat error and the current error change rate, the proportional coefficient, integral coefficient and differential coefficient are dynamically tuned by a piecewise linear function and a limiting function. Based on the tuned proportional coefficient, integral coefficient, and derivative coefficient, as well as the current superheat error, the PID control output for the current control cycle is generated. Based on the PID control output, the target opening value of the electronic expansion valve in the current control cycle is generated.

2. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 1, characterized in that, The evaporator operating data also includes the total heat exchange of the evaporator and the average pressure inside the evaporator; The step of generating the target opening value of the electronic expansion valve in the current control cycle based on the PID control output includes: Based on the total heat exchange of the evaporator and the average pressure inside the evaporator, a heat load feedforward channel and an evaporation pressure feedforward channel are constructed respectively to generate the corresponding heat load feedforward quantity and evaporation pressure feedforward quantity, and the two are superimposed to obtain the total feedforward compensation quantity. The PID control output is superimposed with the total feedforward compensation to obtain the basic control quantity; depending on whether the safety protection condition is triggered, the basic control quantity is selectively superimposed with the corresponding protection compensation quantity to obtain the total control quantity; the target opening value of the electronic expansion valve in the current control cycle is generated based on the total control quantity.

3. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 1, characterized in that, The method involves dynamically adjusting the proportional coefficient, integral coefficient, and differential coefficient based on the current superheat error and the current error change rate, using a piecewise linear function and a limiting function; including: Based on the current superheat error and the current error change rate, generate the proportional scaling factor, integral scaling factor and differential scaling factor respectively; The scaling factor is determined based on the current superheat error and the current error change rate, the integral scaling factor is determined based on the current superheat error, and the differential scaling factor is determined based on the current error change rate. The preset basic scaling factor, basic integral factor, and basic differential factor are multiplied by their respective scaling factors, and then subjected to a scaling factor limit to obtain the updated scaling factor, integral factor, and differential factor.

4. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 1, characterized in that, The process of generating the PID control output for the current control cycle based on the tuned proportional coefficient, integral coefficient, derivative coefficient, and current superheat error includes: Based on the current superheat error, the adjusted proportional coefficient, integral coefficient, and differential coefficient, calculate the proportional term, integral term, and differential term respectively; The calculation of the integral term includes: Based on the current superheat error, the integral term is recursively accumulated over time to obtain the updated integral term; Apply upper and lower threshold limits to the updated integral term. When the integral term exceeds the threshold range, clamp it to the corresponding upper or lower threshold.

5. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 2, characterized in that, The generation of the corresponding heat load feedforward and evaporation pressure feedforward includes: Multiply the total heat exchange of the evaporator by the preset heat load feedforward coefficient to obtain the heat load feedforward amount; The pressure deviation is obtained by subtracting the average pressure inside the evaporator from the rated evaporation pressure, and then multiplying the pressure deviation by a preset evaporation pressure feedforward coefficient to obtain the evaporation pressure feedforward amount.

6. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 2, characterized in that, The step of selectively superimposing the basic control quantity with the corresponding protection compensation quantity based on whether a safety protection condition is triggered to obtain the total control quantity includes: Based on the current actual superheat and the current error rate of change, determine whether the preset safety protection conditions are met. If at least one safety protection condition is triggered, the corresponding compensation amount is generated according to each triggered safety protection condition, and all compensation amounts are linearly superimposed to obtain the total protection compensation amount. The total protection compensation amount is added to the basic control amount to obtain the total control amount; If no safety protection conditions are triggered, the total control quantity equals the basic control quantity.

7. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 6, characterized in that, The security protection conditions include at least one of the following: Superheat determination criteria: The current actual superheat is lower than the first safety threshold; Change rate determination criteria: The current error change rate is lower than the second safety threshold; Specifically, when the superheat determination condition is triggered, a first fixed negative opening compensation amount is generated; when the rate of change determination condition is triggered, a second fixed negative opening compensation amount is generated.

8. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 2, characterized in that, The generation of the target opening value of the electronic expansion valve in the current control cycle based on the total control quantity includes: The opening change rate is limited for the total control quantity, and the limited result is used as the single-step control quantity, where: If the total control quantity is greater than the opening value of the previous control cycle, it is determined to be a valve opening command, and the difference between the total control quantity and the opening value of the previous control cycle is limited to not exceeding the first preset opening change threshold, so as to obtain the single-step control quantity. If the total control quantity is less than the opening value of the previous control cycle, it is determined to be a valve closing command, and the absolute value of the difference between the total control quantity and the opening value of the previous control cycle is limited to not exceeding the second preset opening change threshold, so as to obtain the single-step control quantity. The current opening of the electronic expansion valve is added to the single-step control quantity to obtain the preliminary target opening. An amplitude limit is applied to the preliminary target opening to ensure that it is not lower than the preset minimum opening value and does not exceed the preset maximum opening value, thus obtaining the target opening value of the electronic expansion valve. Wherein, the second preset opening change threshold is greater than the first preset opening change threshold.

9. The adaptive control method for outlet superheat of a battery direct cooling system according to claim 5, characterized in that, Obtaining the rated evaporation pressure includes: Fix the opening of the electronic expansion valve to a preset intermediate opening and run the system; During system operation, the average pressure inside the evaporator, the outlet temperature of the evaporator, and the total heat exchange of the evaporator are continuously monitored. When the fluctuation range of the monitored average pressure inside the evaporator, the outlet temperature of the evaporator, and the total heat exchange of the evaporator in multiple consecutive control cycles does not exceed their respective preset steady-state thresholds, the system is determined to have reached steady state. The average pressure inside the evaporator under steady-state conditions is read as the rated evaporation pressure.

10. An electronic device, comprising: A processor and a memory storing a program, characterized in that the program includes instructions that, when executed by the processor, cause the processor to perform an adaptive control method for outlet superheat of a battery direct cooling system according to any one of claims 1 to 9.

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