A phased adaptive optimization control method for an EVI heat pump temperature-controlled water chiller

Abstract

The application discloses a kind of EVI heat pump temperature control cold water machine stage self-adapting optimization control method, it is related to heat pump temperature control cold water machine technical field, to solve the electronic expansion valve control development test workload of EVI cold water machine and the problem of poor control flexibility;Including the following steps: start unit, determine the cold water machine operating mode, according to the starting duration of compressor judgment starting stage;In the stable control stage of main refrigeration mode, according to dynamic cycle acquisition parameter, according to the first condition judgment opening degree adjustment direction, determine opening degree adjustment amount;In the fast response stage of main refrigeration mode, according to fixed cycle acquisition parameter, judge opening degree adjustment direction and determine opening degree adjustment amount;In selectable heating mode, according to fixed cycle acquisition parameter, according to the second condition judgment opening degree adjustment direction, determine opening degree adjustment amount.By stage, mode of fine control, realize the dynamic matching of spray enthalpy and cold water temperature control demand, precision, energy efficiency and stability are considered.

Description

Technical Field

[0001] This invention relates to the field of heat pump temperature-controlled chiller technology, specifically to a staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller. Background Technology

[0002] As industrial production and commercial buildings increasingly demand higher energy efficiency and adaptability from temperature-controlled chillers, EVI technology is widely used in chiller systems due to its ability to expand the operating temperature range of heat pumps and enhance heating / cooling capabilities in extreme environments. The core of EVI technology is to control the compressor's enthalpy injection through an EVI electronic expansion valve, achieving secondary compression and thus optimizing unit performance.

[0003] Existing EVI chillers mostly use lookup tables for electronic expansion valve control, assigning a fixed opening degree based on ambient and return water temperatures (e.g., CN121782788A). This results in a large workload for development and testing, poor control flexibility, and an inability to fully leverage the advantages of EVI technology. Some models only design control logic for a single operating condition, failing to deeply couple chilled water outlet temperature with EVI injection enthalpy control, leading to insufficient temperature control accuracy (typically chilled water temperature fluctuations of ±1℃ or more), which cannot meet the high-precision requirements of precision equipment cooling and industrial production. Under load fluctuations (such as sudden changes in cooling demand) or extreme environments (ambient temperatures below -25℃ or above 53℃, high humidity, high dust), defects such as response lag, overshoot, exhaust temperature runaway, and long stable operation cycles are prone to occur. At the same time, there is a lack of sensor fault redundancy protection and dynamic energy efficiency optimization mechanisms, resulting in large energy losses under extreme operating conditions and easy unit shutdown or equipment damage due to abnormal situations. Summary of the Invention

[0004] This invention solves the problems of large workload in the development and testing of electronic expansion valve control for EVI chillers and poor control flexibility. It proposes a phased adaptive optimization control method for EVI heat pump temperature-controlled chillers. Through phased and mode-based refined control, it achieves dynamic matching between injection enthalpy and chilled water temperature control requirements, taking into account accuracy, energy efficiency and stability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller includes the following steps: After starting the unit and determining the chiller's operating mode, the start-up stage is determined based on the compressor's start-up time. During the stable control phase of the main cooling mode, parameters are collected dynamically, and the opening adjustment direction is determined based on the first condition to determine the opening adjustment amount. During the rapid response phase of the main cooling mode, parameters are collected at a fixed time to determine the opening adjustment direction and the opening adjustment amount. In selectable heating mode, parameters are collected at fixed intervals, and the opening adjustment direction is determined based on the second condition to determine the opening adjustment amount.

[0007] This technical solution presents a phased adaptive optimization control method for EVI heat pump temperature-controlled chillers. It can regulate the opening changes of the EVI electronic expansion valve, thereby controlling the compressor's injection enthalpy. The control strategy is divided according to the compressor startup stage, and judgment parameters are set according to the operating mode (main cooling mode / selectable heating mode). The precise control of chilled water outlet temperature is deeply coupled with the safety of exhaust temperature. Combined with relevant control logic, the opening can be periodically and precisely adjusted, ultimately ensuring that the chilled water outlet temperature is stable within the set range, while controlling the compressor exhaust temperature within a reasonable range, thus shortening the unit's stable operation time.

[0008] The present invention is further configured such that: the step of determining the start-up stage based on the compressor start-up time includes: Set a compressor start-up threshold N, and determine whether the compressor start-up time is less than N. If yes, enter the stable control phase; otherwise, enter the rapid response phase.

[0009] In this technical solution, the compressor start-up stage is determined by setting a start-up threshold N.

[0010] The present invention is further configured to: during the stable control phase of the main cooling mode, collect parameters according to a dynamic cycle, including: If the cold water temperature deviation ΔTls is greater than 1℃, the dynamic cycle is 15s. If the cold water temperature deviation ΔTls is not greater than 0.5℃, the dynamic cycle is 30s. Determine whether the working condition has changed. If yes, adjust parameters Kp, Kd and Kc. If no, maintain the original dynamic cycle.

[0011] The present invention is further configured such that: the first condition is: if the difference between the current exhaust temperature Tpq and the ambient temperature Thj is less than the cooling target exhaust superheat Ctarget and the cold water temperature deviation ΔTls is not greater than 0, the electronic expansion valve is closed. If the difference between Tpq and Thj is greater than Ctarget+P or |ΔTls| is greater than 0.3℃, the electronic expansion valve opens wider; If the difference between Tpq and Thj is between Ctarget and Ctarget+P and |ΔTls| is not greater than 0.3℃, the opening of the electronic expansion valve remains unchanged.

[0012] The present invention is further configured such that: the second condition is: if the difference between the current exhaust temperature Tpq and the hot water outlet temperature Tcs is less than the heating target exhaust superheat Htarget, the electronic expansion valve is closed. If the difference between Tpq and Tcs is greater than Htarget+P or the hot water temperature deviation ΔTcs is greater than 1℃, the electronic expansion valve will open wider. If the difference between Tpq and Tcs is between Htarget and Htarget+P, the opening of the electronic expansion valve remains unchanged.

[0013] The present invention is further configured such that: during the stable control phase of the main cooling mode, the opening change of the electronic expansion valve is determined according to the parameters Kp, KI, Kd and Kc, with the dynamic period Ttc as the period.

[0014] The present invention is further configured such that: during the rapid response phase of the main cooling mode, with M as a fixed period, the opening change of the electronic expansion valve when it is closed is determined based on the current exhaust temperature Tpq, ambient temperature Thj, cooling target exhaust superheat Ctarget, and exhaust temperature change ΔTd; and the opening change of the electronic expansion valve when it is fully open is determined based on the current exhaust temperature Tpq, ambient temperature Thj, cooling target exhaust superheat Ctarget, and chilled water temperature deviation ΔTls.

[0015] The present invention is further configured such that: the selectable heating mode includes a stable control phase and a rapid response phase. In the stable control phase of the selectable heating mode, with Tth as a fixed period, the opening change of the electronic expansion valve when it is closed and opened is determined according to the exhaust temperature Tpq, the hot water outlet temperature Tcs, the heating target exhaust superheat Htarget, and the exhaust temperature change ΔTd.

[0016] The present invention is further configured such that, during the rapid response phase of the selectable heating mode, with M as a fixed period, the opening change of the electronic expansion valve when it is closed and opened is determined based on the exhaust temperature Tpq, the hot water outlet temperature Tcs, the heating target exhaust superheat Htarget, and the exhaust temperature change ΔTd.

[0017] The present invention is further configured such that: if the cold water outlet temperature Tls is less than the minimum threshold Tlsmin of the cold water temperature protection or Tls is greater than the maximum threshold Tlsmax of the cold water temperature protection, the electronic expansion valve makes an emergency adjustment, closing or opening by 20%.

[0018] The present invention provides a staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller, which can bring the following beneficial effects: The control strategy is divided according to the compressor start-up stage, and the judgment parameters are set according to the operating mode (main cooling mode / selectable heating mode). The precise control of chilled water outlet temperature is deeply coupled with the safety of exhaust temperature. Combined with proportional-derivative (PD) control logic and load dynamic response mechanism, the opening degree is periodically and precisely adjusted, which ultimately ensures that the chilled water outlet temperature is stable within the set range, while controlling the compressor exhaust temperature within a reasonable range, shortening the stable operation time of the unit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the main cooling mode of the phased adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to the present invention.

[0020] Figure 2 This is a schematic diagram of the selectable heating mode of the phased adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to the present invention. Detailed Implementation

[0021] Example 1:

[0022] The parameters involved in this embodiment are defined and explained here.

[0023] The compressor start-up threshold N is the critical time for the unit to enter the stable control phase after startup (in this embodiment, the default is 5 minutes, but it can be set to 3 to 10 minutes depending on the model).

[0024] For the exhaust superheat Ctarget, it is the optimal exhaust superheat set in the main cooling mode (in this embodiment, the default is 30°C, which can be adjusted according to the refrigerant type).

[0025] The exhaust superheat Htarget is the optimal exhaust superheat set in the selectable heating mode (in this embodiment, the default is 45°C).

[0026] The current exhaust temperature Tpq is the real-time temperature of the compressor exhaust port (specifically obtained through an exhaust temperature sensor).

[0027] The chilled water outlet temperature Tls is the real-time temperature of the chiller heat exchanger outlet (specifically obtained through an outlet temperature sensor).

[0028] For the chilled water set temperature Tlsset, it is the target chilled water temperature set by the user (e.g., 7°C, 10°C).

[0029] The cold water temperature deviation ΔTls is the difference between the set cold water temperature and the real-time outlet water temperature. That is, ΔTls equals the set cold water temperature Tlsset minus the outlet cold water temperature Tls. If the cold water temperature deviation ΔTls is positive, the cold water is warmer; if the cold water temperature deviation ΔTls is negative, the cold water is colder.

[0030] The rate of change of chilled water temperature deviation ΔTlsrate is the change of ΔTls per unit time. That is, the rate of change of chilled water temperature deviation ΔTlsrate is equal to the instantaneous ΔTls(n) minus the ΔTls(n-1) of the previous unit time. The rate of change of chilled water temperature deviation ΔTlsrate can mainly be used to judge the intensity of load fluctuation.

[0031] The ambient temperature Thj is the real-time temperature of the external environment of the chiller (specifically obtained through an ambient temperature sensor).

[0032] The hot water outlet temperature Tcs is the real-time temperature of the hot water outlet in the selectable heating mode (specifically obtained through a hot water temperature sensor).

[0033] The hot water set temperature Tcsset is the target hot water temperature set by the user in the selectable heating mode.

[0034] The hot water temperature deviation ΔTcs is the difference between the set hot water temperature and the real-time outlet water temperature. Specifically, the hot water temperature deviation ΔTcs is equal to the set hot water temperature Tcsset minus the outlet hot water temperature Tcs.

[0035] The change in exhaust temperature ΔTd is the difference between the current exhaust temperature and the exhaust temperature in the previous sampling period.

[0036] For non-regulated temperature difference P, it is the temperature range to avoid frequent valve operation (in this embodiment, the default is 3℃, and it can be set to 2℃ if the deviation is small).

[0037] For the exhaust proportional coefficient Kp of the electronic expansion valve, it is a proportional parameter in PD control (in this embodiment, the default value is 10, which reflects the deviation response speed and can be adaptively corrected).

[0038] For the differential coefficient Kd of the electronic expansion valve exhaust, it is the differential parameter in PD control (in this embodiment, the default value is 15 to suppress temperature fluctuations, and it can be adaptively corrected). For the electronic expansion valve cooling regulation coefficient Kc, it is the opening adjustment gain of the cooling mode in the steady stage (in this embodiment, the default value is 2, which can be adaptively corrected).

[0039] For the heating regulation coefficient Kh of the electronic expansion valve, it is the opening adjustment gain of the selectable heating mode (in this embodiment, the default value is 1, which can be adaptively corrected).

[0040] The cooling load factor Kl reflects the intensity of the cooling load. The cooling load factor Kl is equal to 1 plus |ΔTls| plus |ΔTlsrate|, and the range of the cooling load factor Kl is 1 to 3.

[0041] The heating load factor Klheat reflects the intensity of the heating load. The heating load factor Klheat is equal to 1 plus |ΔTcs|.

[0042] The dynamic cooling regulation cycle Ttc is the valve adjustment cycle in the stable cooling mode (Ttc is 15 seconds when ΔTls is greater than 1℃; Ttc is 30 seconds when ΔTls is not greater than 0.5℃).

[0043] The heating adjustment cycle Tth is the valve adjustment cycle in the selectable heating mode (in this embodiment, the default is 10 seconds).

[0044] The adjustment cycle M during the start-up phase is the valve adjustment cycle within N minutes of compressor start-up (in this embodiment, the default is 5 seconds).

[0045] The valve opening change S is the opening adjustment value of the EVI electronic expansion valve in each adjustment cycle (unit: step).

[0046] For the cold water temperature protection thresholds Tlsmin / Tlsmax, which are emergency protection boundaries, Tlsmin equals Tlsset minus 3℃, and Tlsmax equals Tlsset plus 5℃.

[0047] To address the issues of high development and testing workload and poor control flexibility in the electronic expansion valve control of EVI chillers, this embodiment proposes a staged adaptive optimization control method for EVI heat pump temperature-controlled chillers, referencing... Figure 1 and Figure 2 It mainly includes the following steps.

[0048] After starting the unit and determining the chiller's operating mode, the startup stage is determined based on the compressor's startup time.

[0049] To determine the start-up phase based on the compressor start-up time, a more detailed approach is to first pre-set a corresponding compressor start-up threshold N, and then determine whether the compressor start-up time is less than the compressor start-up threshold N. If the compressor start-up time is less than the compressor start-up threshold N, the system enters the stable control phase; if the compressor start-up time is not less than the compressor start-up threshold N, the system enters the rapid response phase.

[0050] During the stable control phase of the main cooling mode, parameters are collected on a dynamic cycle, and the opening adjustment direction and adjustment amount are determined based on the first condition. During the rapid response phase of the main cooling mode, parameters are collected on a fixed cycle, and the opening adjustment direction and adjustment amount are determined based on the first condition.

[0051] In the main cooling mode, the control logic takes "stable chilled water temperature + safe exhaust temperature" as the dual objectives. It combines the cooling target exhaust superheat, chilled water outlet temperature, ambient temperature, load coefficient and exhaust temperature change to determine and adjust the opening of the EVI electronic expansion valve.

[0052] During the stable control phase of the main cooling mode, parameters are collected according to a dynamic cycle, which mainly includes the following process: if the chilled water temperature deviation ΔTls is greater than 1℃, the dynamic cycle is 15s; if the chilled water temperature deviation ΔTls is not greater than 0.5℃, the dynamic cycle is 30s. It is determined whether the operating conditions have changed. If so, the discharge differential coefficient Kp, discharge differential coefficient Kd, and cooling regulation coefficient Kc of the electronic expansion valve are corrected. If not, the original dynamic cycle is maintained.

[0053] In the main cooling mode, the first condition is: if the difference between the current exhaust temperature Tpq and the ambient temperature Thj is less than the cooling target exhaust superheat Ctarget and the chilled water temperature deviation ΔTls is not greater than 0, that is, the chilled water is too cold and the exhaust superheat is insufficient. At this time, the EVI electronic expansion valve will periodically close.

[0054] If the difference between the current exhaust temperature Tpq and the ambient temperature Thj is greater than Ctarget+P or |ΔTls| is greater than 0.3℃, that is, the exhaust superheat is too high or the cold water temperature is higher than the set value, the EVI electronic expansion valve will periodically open.

[0055] If the difference between the current exhaust temperature Tpq and the ambient temperature Thj is between Ctarget and Ctarget+P, and |ΔTls| is not greater than 0.3℃, then the exhaust superheat meets the standard. The cold water temperature fluctuation is also within the allowable range, and the opening of the EVI electronic expansion valve remains unchanged.

[0056] If the cold water outlet temperature Tls is less than the minimum threshold Tlsmin of the cold water temperature protection or greater than the maximum threshold Tlsmax of the cold water temperature protection, the EVI electronic expansion valve will be adjusted in an emergency (closed / opened by 20%) to avoid equipment damage.

[0057] During the stable control phase of the main refrigeration mode, with a dynamic period Ttc (15-30s) as the cycle, the opening change of the electronic expansion valve is determined according to the electronic expansion valve exhaust differential coefficient Kp, refrigeration load coefficient Kl, electronic expansion valve exhaust differential coefficient Kd, and electronic expansion valve refrigeration regulation coefficient Kc.

[0058] More specifically, when the electronic expansion valve is closed, with the dynamic period Ttc as the period, the change in opening S is equal to the first intermediate term minus the second intermediate term minus |ΔTls|, then multiplied by 1 and divided by the cooling load coefficient KI. The first intermediate term is Ctarget minus Tpq minus Thj, then multiplied by the cooling regulation coefficient Kc of the electronic expansion valve, and the second intermediate term is the exhaust differential coefficient Kd of the electronic expansion valve multiplied by the change in exhaust temperature ΔTd.

[0059] More specifically, when the electronic expansion valve is fully open, the opening change S is equal to the third intermediate term plus the second intermediate term, multiplied by the cooling load coefficient KI, and then ΔTls multiplied by 2; the third intermediate term is equal to Tpq minus Thj minus Ctarget, and then multiplied by the electronic expansion valve cooling regulation coefficient Kc; the second intermediate term is the electronic expansion valve exhaust differential coefficient Kd multiplied by the exhaust temperature change ΔTd.

[0060] During the rapid response phase of the main cooling mode, with M as a fixed period, the opening change of the electronic expansion valve when it is closed is determined based on the current exhaust temperature Tpq, ambient temperature Thj, cooling target exhaust superheat Ctarget, and exhaust temperature change ΔTd. The opening change of the electronic expansion valve when it is fully open is determined based on the current exhaust temperature Tpq, ambient temperature Thj, cooling target exhaust superheat Ctarget, and chilled water temperature deviation ΔTls.

[0061] More specifically, when the electronic expansion valve is closed, with a period of M equal to 5 seconds, the change in opening S is equal to Ctarget minus Tpq plus Thj minus the fourth intermediate term, the result is then divided by 2, multiplied by 1, and then divided by the cooling load coefficient KI; the fourth intermediate term is equal to the electronic expansion valve exhaust differential coefficient Kp multiplied by the exhaust temperature change ΔTd. That is, the larger the load, the smaller the closure amplitude, to avoid overcooling of the chilled water.

[0062] More specifically, when the electronic expansion valve opens fully, with a period of M equal to 5 seconds, the change in opening S is equal to Tpq minus Thj minus C_target plus the fourth intermediate term, then multiplied by the cooling load coefficient KI, plus ΔTls multiplied by 3. That is, the larger the load, the larger the adjustment, resulting in rapid cooling.

[0063] In selectable heating mode, parameters are collected at fixed intervals, and the opening adjustment direction is determined based on the second condition to determine the opening adjustment amount.

[0064] In the selectable heating mode, the control logic aims to achieve "hot water temperature meets the standard + exhaust temperature is controllable". It adjusts the opening of the EVI electronic expansion valve by combining the exhaust superheat of the heating target, the hot water outlet temperature, the load factor and the change in exhaust temperature.

[0065] Specifically, in the selectable heating mode, the second condition is: if the difference between the current exhaust temperature Tpq and the hot water outlet temperature Tcs is less than the heating target exhaust superheat Htarget, it indicates that the exhaust superheat is insufficient, and the EVI electronic expansion valve is closed.

[0066] If the difference between the current exhaust temperature Tpq and the hot water outlet temperature Tcs is greater than Htarget+P or the hot water temperature deviation ΔTcs is greater than 1℃, it indicates that the exhaust superheat is too high or the hot water temperature does not meet the standard, and the EVI electronic expansion valve opens wider.

[0067] If the difference between the current exhaust temperature Tpq and the hot water outlet temperature Tcs is between Htarget and Htarget+P, it indicates that the exhaust superheat meets the standard and the opening of the electronic expansion valve remains unchanged.

[0068] During the stable control phase of the selectable heating mode, with Tth as the fixed period, the opening change of the electronic expansion valve when it is closed and opened is determined based on the exhaust temperature Tpq, hot water outlet temperature Tcs, heating target exhaust superheat Htarget, and exhaust temperature change ΔTd.

[0069] More specifically, when the electronic expansion valve is closed, with a period of Tth equal to 10s, the change in opening S is equal to the fifth intermediate term minus the product of the second and sixth intermediate terms; the fifth intermediate term is Htarget minus Tpq minus Tcs, then multiplied by the heating regulation coefficient Kh of the electronic expansion valve, the second intermediate term is the exhaust differential coefficient Kd of the electronic expansion valve multiplied by the change in exhaust temperature ΔTd, and the sixth intermediate term is 1 divided by Klheat.

[0070] More specifically, when the electronic expansion valve is fully opened, with a period of Tth equal to 10s, the change in opening S is equal to the product of the seventh intermediate term plus the second intermediate term and Klheat, where the seventh intermediate term is Tpq minus Tcs minus Htarget.

[0071] During the rapid response phase of the selectable heating mode, with M as the fixed period, the change in the opening degree of the electronic expansion valve when it is closed and opened is determined based on the exhaust temperature Tpq, the hot water outlet temperature Tcs, the heating target exhaust superheat Htarget, and the change in exhaust temperature ΔTd.

[0072] More specifically, when the electronic expansion valve is closed, with a period of M equal to 5, the change in opening S is equal to Htarget minus Tpq plus Tcs, then the fourth intermediate term is subtracted, and the result is multiplied by the sixth intermediate term; the sixth intermediate term is 1 divided by Klheat, and the fourth intermediate term is equal to the electronic expansion valve exhaust differential coefficient Kp multiplied by the change in exhaust temperature ΔTd.

[0073] More specifically, when the electronic expansion valve is fully opened, with a period of M equal to 5, the change in opening S is equal to Tpq minus Tcs minus Htarget, then the fourth intermediate term is added, and the result is multiplied by Klheat.

[0074] In the above embodiments, the electronic expansion valve exhaust differential coefficient Kp, electronic expansion valve exhaust differential coefficient Kd, and electronic expansion valve refrigeration regulation coefficient Kc have different correction values ​​under different operating conditions.

[0075] When the ambient temperature is 15-30℃ (stable at room temperature), the correction value of the exhaust differential coefficient Kp of the electronic expansion valve is 8-10, the correction value of the exhaust differential coefficient Kd of the electronic expansion valve is 12-15, and the correction value of the refrigeration regulation coefficient Kc of the electronic expansion valve is 1.8-2.0. The purpose of optimization is to avoid overshoot and improve energy efficiency.

[0076] When the ambient temperature is greater than 53℃ (extreme high temperature), the correction value of the exhaust differential coefficient Kp of the electronic expansion valve is 12-15, the correction value of the exhaust differential coefficient Kd of the electronic expansion valve is 18-20, and the correction value of the cooling regulation coefficient Kc of the electronic expansion valve is 2.2-2.5. The purpose of optimization is to enhance the response and avoid excessive exhaust temperature.

[0077] When the ambient temperature is less than -25℃ (extreme low temperature), the correction value of the exhaust differential coefficient Kp of the electronic expansion valve is 10-12, the correction value of the exhaust differential coefficient Kd of the electronic expansion valve is 15-18, and the correction value of the refrigeration regulation coefficient Kc of the electronic expansion valve is 2.0-2.2. The purpose of optimization is to ensure the injection enthalpy and stabilize the refrigeration capacity.

[0078] When the load fluctuates greatly, i.e. |ΔTls_rate| is greater than 0.5℃ / min, the correction value of the electronic expansion valve exhaust differential coefficient Kp is 12-14, the correction value of the electronic expansion valve exhaust differential coefficient Kd is 18-20, and the correction value of the electronic expansion valve refrigeration regulation coefficient Kc is 2.0-2.3. The optimization purpose is to respond quickly to load changes.

[0079] refer to Figure 1 It can display the control logic flow of the compressor within N minutes of startup (rapid response phase) and after N minutes of startup (stable control phase) in cooling mode. The process starts with the unit startup. First, it determines whether the compressor startup time is less than N minutes. If so, it enters the rapid response phase and calculates the adjustment amount according to the corresponding cycle (M=5 seconds) and the opening formula. Otherwise, it enters the stable control phase. First, it determines the size of the chilled water temperature deviation ΔTls to determine the dynamic adjustment cycle Ttc, and then calculates the adjustment amount in combination with the exhaust superheat and load factor parameters. The process includes an abnormal temperature judgment branch (whether Tls exceeds Tlsmin / Tlsmax). When triggered, it performs emergency adjustment. It also includes a parameter adaptive correction logic node to correct the Kp, Kd, ​​and Kc parameters according to the ambient temperature and load fluctuation.

[0080] refer to Figure 2It can display the control logic flow of the heating mode. The starting point is the start of the heating mode. First, the hot water outlet temperature sensor collects Tcs and calculates ΔTcs. Combined with the exhaust temperature Tpq, the actual exhaust superheat is calculated and compared with the heating target exhaust superheat Htarget to determine whether the valve should be closed, opened, or kept unchanged. Then, based on the compressor start-up time, it is determined whether it has entered the stable control stage. The adjustment amount is calculated according to the corresponding cycle (start-up stage M=5 seconds, stable stage Tth=10 seconds) and the opening formula to achieve dual control of hot water temperature reaching the target and exhaust temperature safety.

[0081] Example 2:

[0082] Based on Example 1, this example of a phased adaptive optimization control method for an EVI heat pump temperature-controlled chiller also employs a sensor fault redundancy mechanism, an extreme environment compensation mechanism, and an energy efficiency optimization mechanism.

[0083] For the sensor fault redundancy mechanism: If the chilled water outlet temperature sensor (Tls) fails: Estimate Tls using "ambient temperature Thj + exhaust temperature Tpq" (Tlsest equals Thj minus 0.6 times (Tpq-60)), continue control based on the estimated value, and trigger a fault alarm simultaneously. If the ambient temperature sensor (Thj) fails: Fix Ctarget to 28℃ and Kp to 12 to ensure basic unit operation and avoid shutdown.

[0084] For extreme environment compensation mechanisms: In high humidity environments (relative humidity > 85%): shorten the cooling regulation cycle Ttc to 15 seconds and increase the Kd coefficient to 18 to suppress temperature fluctuations caused by decreased heat exchange efficiency; In high dust environments (detected by differential pressure sensor): perform a "micro-opening-micro-closing" action every 30 minutes (opening degree change ± 5 steps) to prevent electronic expansion valve from jamming and ensure regulation accuracy.

[0085] For the energy efficiency optimization mechanism, when |ΔTls| is not greater than 0.3℃ and the ambient temperature is 15-30℃, Kp is automatically reduced to 8, the adjustment cycle is extended to 30 seconds, the frequency of valve action is reduced, and the COP (energy efficiency ratio) is increased by 8%-12%; under light load conditions (Kl is not greater than 1.2): the adjustment range of EVI injection enthalpy is reduced to avoid energy loss caused by excessive injection enthalpy.

[0086] In this technical solution, if the sensor malfunctions, the redundant module starts parameter estimation, transmits the estimated value to the main control logic, and triggers an alarm. In extreme environments with high humidity and high dust, the compensation module sends signals for period adjustment and coefficient correction to the main logic. When the energy efficiency optimization conditions are met, the energy efficiency module outputs signals for Kp correction and period extension, allowing the main control logic and the optimization module to work together.

Claims

1. A staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller, characterized in that, Includes the following steps: After starting the unit and determining the chiller's operating mode, the start-up stage is determined based on the compressor's start-up time. During the stable control phase of the main cooling mode, parameters are collected according to a dynamic cycle, and the opening adjustment direction is determined based on the first condition to determine the opening adjustment amount. During the rapid response phase of the main cooling mode, parameters are collected at fixed intervals to determine the direction of opening adjustment and the amount of opening adjustment. In selectable heating mode, parameters are collected at fixed intervals, and the opening adjustment direction is determined based on the second condition to determine the opening adjustment amount.

2. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 1, characterized in that, The step of determining the startup stage based on the compressor startup time includes: Set a compressor start-up threshold N, and determine whether the compressor start-up time is less than N. If yes, enter the stable control phase; otherwise, enter the rapid response phase.

3. A staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 1 or 2, characterized in that, During the stable control phase of the main cooling mode, parameters are collected dynamically, including: If the cold water temperature deviation ΔTls is greater than 1℃, the dynamic cycle is 15s. If the cold water temperature deviation ΔTls is not greater than 0.5℃, the dynamic cycle is 30s. Determine whether the working condition has changed. If yes, adjust parameters Kp, Kd and Kc. If no, maintain the original dynamic cycle.

4. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 3, characterized in that, The first condition is: if the difference between the current exhaust temperature Tpq and the ambient temperature Thj is less than the target exhaust superheat Ctarget and the cold water temperature deviation ΔTls is not greater than 0, the electronic expansion valve is closed. If the difference between Tpq and Thj is greater than Ctarget+P or |ΔTls| is greater than 0.3℃, the electronic expansion valve opens wider; If the difference between Tpq and Thj is between Ctarget and Ctarget+P and |ΔTls| is not greater than 0.3℃, the opening of the electronic expansion valve remains unchanged.

5. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 3, characterized in that, The second condition is: if the difference between the current exhaust temperature Tpq and the hot water outlet temperature Tcs is less than the heating target exhaust superheat Htarget, the electronic expansion valve will close slightly. If the difference between Tpq and Tcs is greater than Htarget+P or the hot water temperature deviation ΔTcs is greater than 1℃, the electronic expansion valve will open wider. If the difference between Tpq and Tcs is between Htarget and Htarget+P, the opening of the electronic expansion valve remains unchanged.

6. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 3, characterized in that, During the stable control phase of the main cooling mode, the opening change of the electronic expansion valve is determined according to the parameters Kp, KI, Kd and Kc, with the dynamic cycle Ttc as the period.

7. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 6, characterized in that, During the rapid response phase of the main cooling mode, with M as a fixed period, the opening change of the electronic expansion valve when it is closed is determined based on the current exhaust temperature Tpq, ambient temperature Thj, cooling target exhaust superheat Ctarget, and exhaust temperature change ΔTd. The opening change of the electronic expansion valve when it is fully open is determined based on the current exhaust temperature Tpq, ambient temperature Thj, cooling target exhaust superheat Ctarget, and chilled water temperature deviation ΔTls.

8. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 3, characterized in that, The selectable heating modes include a stable control phase and a rapid response phase. In the stable control phase of the selectable heating mode, with Tth as a fixed period, the opening change of the electronic expansion valve when it is closed and opened is determined based on the exhaust temperature Tpq, the hot water outlet temperature Tcs, the heating target exhaust superheat Htarget, and the exhaust temperature change ΔTd.

9. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 8, characterized in that, During the rapid response phase of the selectable heating mode, with M as the fixed period, the change in the opening degree of the electronic expansion valve when it is closed and opened is determined based on the exhaust temperature Tpq, the hot water outlet temperature Tcs, the heating target exhaust superheat Htarget, and the change in exhaust temperature ΔTd.

10. The staged adaptive optimization control method for an EVI heat pump temperature-controlled chiller according to claim 4, characterized in that, If the cold water outlet temperature Tls is less than the minimum threshold Tlsmin of the cold water temperature protection or greater than the maximum threshold Tlsmax of the cold water temperature protection, the electronic expansion valve will make emergency adjustments, either closing it slightly or opening it by 20%.

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