Enhanced dehumidification method of air source heat pump suitable for high humidity environments

Abstract

This invention relates to the field of air conditioning and heat pump control technology, and discloses an enhanced dehumidification method for air-source heat pumps suitable for high-humidity environments. This method acquires indoor environmental state parameters and the actual intake and exhaust superheat on the refrigerant side; injects a frequency command with a step pulse into the variable frequency compressor, extracts the transient rise slope of the actual exhaust superheat, and calculates the implicit liquid-phase buffer coefficient characterizing the degree of liquid refrigerant accumulation in the gas-liquid separator; calculates the target evaporation temperature based on the dew point temperature, absolute humidity change rate, and implicit liquid-phase buffer coefficient, and adjusts the compressor operating frequency; calculates the actual apparent latent ratio based on the temperature and humidity change rate, and outputs the indoor fan speed command. This invention implements dynamic feedforward control by quantifying the degree of liquid refrigerant accumulation, significantly improving dehumidification capacity in high-humidity environments while ensuring compressor operation safety, and resolving the contradiction between deep dehumidification and liquid slugging prevention.

Description

Technical Field

[0001] This invention relates to the field of air conditioning and heat pump control technology, specifically to an air-source heat pump dehumidification enhancement method suitable for high humidity environments. Background Technology

[0002] When handling high-humidity environments, air-source heat pumps need to lower the evaporation temperature below the air's dew point to achieve effective dehumidification. As the evaporation temperature decreases, the probability of incomplete refrigerant vaporization inside the evaporator increases. Incompletely vaporized liquid refrigerant enters the gas-liquid separator through the return gas line and accumulates there. When the accumulated amount exceeds the separator's capacity limit, the liquid refrigerant is directly drawn into the inverter compressor, causing liquid slugging and damage to the compressor's mechanical structure.

[0003] Existing heat pump systems typically use fixed suction superheat or exhaust superheat thresholds as the basis for preventing liquid slugging. When the sensor detects that the superheat is below the set threshold, the system triggers a protection mechanism, forcibly reducing the compressor's operating frequency or shutting it down directly. This feedback control method based on a fixed threshold has significant physical lag. Because the gas-liquid separator itself has a certain volumetric buffering effect, the decrease in the pipeline superheat parameter often lags behind the actual liquid phase accumulation process inside the gas-liquid separator.

[0004] To mitigate the risk of liquid slugging caused by this lag, existing control strategies often set overheat protection thresholds conservatively. This conservative setting leads to the system prematurely limiting compressor output and exiting deep dehumidification mode even when the gas-liquid separator still has a buffer margin. Furthermore, conventional systems lack quantitative assessment methods for the actual accumulation of liquid refrigerant inside the gas-liquid separator, forcing the control logic to perform only a coarse switching between normal operation and protection activation. This inherent technical deficiency makes it difficult for existing air-source heat pumps to accurately balance ensuring the safe operation of the variable frequency compressor with maximizing the system's dehumidification potential in high-humidity environments, ultimately resulting in insufficient dehumidification capacity under high-humidity conditions.

[0005] Therefore, how to quantitatively assess the accumulation of liquid refrigerant in a gas-liquid separator and achieve dynamic safety boundary control without increasing hardware costs has become a pressing technical problem in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an enhanced dehumidification method for air source heat pumps suitable for high humidity environments. This method solves the problem that existing air source heat pumps, which use a fixed superheat threshold for liquid slugging protection in high humidity environments, suffer from control lag and conservative settings. This results in the system being unable to quantitatively assess the accumulation of liquid refrigerant in the gas-liquid separator, making it difficult to strike a balance between ensuring compressor operation safety and maximizing deep dehumidification capabilities, thus limiting the actual dehumidification capacity.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an enhanced air-source heat pump dehumidification method suitable for high-humidity environments, comprising the following steps: The system acquires indoor environmental parameters and calculates the dew point temperature, absolute humidity, and absolute humidity change rate of the air. Simultaneously, it acquires the actual suction superheat and actual discharge superheat on the refrigerant side. Within a set detection cycle, it injects a frequency command with a step pulse into the variable frequency compressor, extracts the transient rise slope of the actual discharge superheat, and calculates the implicit liquid-phase buffer coefficient, which characterizes the degree of liquid refrigerant accumulation inside the gas-liquid separator. Based on the calculated dew point temperature and absolute humidity change rate, and using the implicit liquid-phase buffer coefficient as a safety boundary coefficient, it calculates the target evaporation temperature to adjust the basic operating frequency of the variable frequency compressor. It calculates the actual apparent latent temperature ratio (ALPR) under the current operating condition based on the ratio of the return air temperature change rate to the absolute humidity change rate, and outputs the target speed command for the indoor fan based on the deviation between the actual and target APR. Based on the implicit liquid-phase buffer coefficient, it performs a weighted calculation between the actual suction superheat control boundary and the actual discharge superheat control boundary to obtain the comprehensive control deviation, and adjusts the opening of the electronic expansion valve based on the comprehensive control deviation.

[0008] The process of injecting a frequency command with a step pulse into the variable frequency compressor includes: triggering a detection cycle, temporarily suspending the outer loop frequency adjustment program of the variable frequency compressor and locking the current base operating frequency; superimposing a preset frequency step pulse amplitude onto the base operating frequency, and continuously outputting a command frequency with a positive step pulse to the variable frequency compressor. The duration of the detection cycle is configured to be greater than the thermal time constant of the exhaust temperature sensor and less than the time required for the overall refrigeration cycle of the system to reach a new steady-state equilibrium.

[0009] The calculation principle of the implicit liquid phase buffer coefficient is as follows: within the effective data extraction window after removing the system's preset dead zone time constant, extract the data sequence of actual exhaust superheat; use the least squares method to linearly fit the data sequence to extract the transient rise slope; calculate the difference between the reference rise slope constant when there is no liquid refrigerant accumulation inside the gas-liquid separator under calibration conditions and the transient rise slope, and obtain the proportion of this difference to the reference rise slope constant to obtain the normalized implicit liquid phase buffer coefficient.

[0010] The calculation process for the target evaporation temperature is as follows: the basic dew point offset is calculated by combining the deviation between the return air relative humidity and the target set relative humidity and the absolute humidity change rate; the implicit liquid phase buffer coefficient is multiplied by the preset liquid phase buffer penalty coefficient, and this product term is used as a constraint to dynamically reduce the basic dew point offset to obtain the optimized dew point offset; the target evaporation temperature is generated by subtracting the optimized dew point offset from the air dew point temperature.

[0011] The invention also includes the step of implementing anti-liquid hammer protection: real-time monitoring of the implicit liquid phase buffer coefficient and the actual exhaust superheat; when it is determined that the implicit liquid phase buffer coefficient is greater than or equal to one, or the actual exhaust superheat is less than the preset exhaust superheat limit threshold, it is determined that the anti-liquid hammer protection condition is met, and the system triggers the interruption intervention program. The execution logic of the interruption intervention program includes: interrupting the control of the actuator by the target evaporation temperature, target speed command and comprehensive control deviation; forcibly reducing the opening of the electronic expansion valve to the minimum safe opening constant; controlling the frequency of the variable frequency compressor to decrease to the anti-liquid hammer safe frequency constant; and controlling the indoor fan speed to increase to the maximum speed constant; when the actual exhaust superheat rises to a level greater than the exhaust superheat recovery threshold and the maintenance time exceeds the delay confirmation period, the interruption intervention program is exited and normal closed-loop control is restored.

[0012] This invention provides an enhanced dehumidification method for air-source heat pumps suitable for high-humidity environments. It offers the following advantages: 1. This invention injects a frequency command with a step pulse into the variable frequency compressor, extracts the transient rise slope of the actual exhaust superheat, and calculates the implicit liquid phase buffer coefficient. Without the need to add an additional physical liquid level sensor inside the gas-liquid separator, it can quantitatively assess the accumulation degree of liquid refrigerant, transforming the hysteresis anti-liquid hammer protection based on a fixed threshold trigger into a feedforward state recognition with continuous measurement capabilities, thereby improving the operational safety of the heat pump system.

[0013] 2. This invention uses the implicit liquid phase buffer coefficient as a safety boundary parameter to dynamically constrain the calculation of the target evaporation temperature, and uses it to weightedly allocate the comprehensive control deviation of the suction superheat and exhaust superheat to adjust the opening of the electronic expansion valve. This allows the system to increase the dew point offset to perform deep dehumidification when the implicit liquid phase buffer coefficient is low, and automatically tighten the control boundary when the implicit liquid phase buffer coefficient increases. This resolves the contradiction between deep dehumidification and compressor liquid slugging prevention in high humidity environments, and improves the actual dehumidification capacity of the heat pump.

[0014] 3. This invention calculates the actual sensible heat-latent heat ratio under the current operating conditions based on the ratio of the return air temperature change rate to the absolute humidity change rate, and adjusts the indoor fan speed in a closed loop based on the deviation between the actual sensible heat-latent heat ratio and the target sensible heat-latent heat ratio. It can dynamically adjust the distribution ratio of cooling capacity between sensible heat and latent heat according to the actual changes in indoor temperature and humidity, thereby optimizing the energy efficiency level of the whole machine while meeting dehumidification requirements. Attached Figure Description

[0015] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a physical architecture diagram of the refrigerant circulation and sensor arrangement of the air conditioning system of the present invention; Figure 3 This is a hardware architecture diagram of the dehumidification enhancement control device of the present invention; Figure 4 This is a comparison chart of the evolution of indoor relative humidity under wet conditions according to the present invention; Figure 5 This invention provides a comparison of indoor temperature evolution under high humidity conditions. Figure 6 This is a schematic diagram of the adaptive adjustment response of the present invention. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see the appendix Figure 1 - Appendix Figure 6 This invention provides an air-source heat pump dehumidification enhancement system suitable for high-humidity environments, including a compressor, a four-way reversing valve, an outdoor heat exchanger, an electronic expansion valve, and an indoor heat exchanger. These components are sequentially connected via refrigerant piping to form a closed-loop refrigerant circulation circuit. In dehumidification operation mode, the outdoor heat exchanger operates as a condenser, the indoor heat exchanger operates as an evaporator, and the compressor is a variable frequency compressor.

[0018] An indoor fan is installed on the indoor heat exchanger side. The indoor fan is a brushless DC fan that receives pulse width modulation signals to adjust its speed. The system is also equipped with a gas-liquid separator. The gas-liquid separator is located between the outlet of the indoor heat exchanger and the suction port of the compressor, and is used for the separation of the gas and liquid phases of the refrigerant and the buffering of the liquid refrigerant.

[0019] The system also includes a sensor network for collecting environmental and refrigerant status parameters. The sensor network includes indoor temperature and humidity sensors, evaporator pipe temperature sensors, condenser pipe temperature sensors, suction temperature sensors, and discharge temperature sensors. The indoor temperature and humidity sensor is located at the return air vent of the indoor heat exchanger to collect indoor return air temperature and relative humidity. The evaporator pipe temperature sensor is located in the middle section of the indoor heat exchanger coil. The condenser pipe temperature sensor is located in the middle section of the outdoor heat exchanger coil. The suction temperature sensor is located on the piping side between the gas-liquid separator and the compressor suction port. The discharge temperature sensor is located on the piping side between the compressor discharge port and the four-way reversing valve.

[0020] The system is equipped with a microcontroller, which is electrically connected to the compressor, electronic expansion valve, and indoor fan, and also connects to various sensors in the sensor network to receive collected signals. The microcontroller has a built-in system control program that processes the input signals and outputs control commands to each actuator.

[0021] Based on the program execution logic inside the microcontroller, this system can be divided into several functional modules: a humid air analysis module, an implicit thermodynamic identification module, a dew point offset optimization module, a sensible heat ratio decoupling control module, and a dual-boundary switching control module.

[0022] The humid air analysis module communicates with the indoor temperature and humidity sensor to calculate the dew point temperature and absolute humidity of the air based on the return air temperature and relative humidity, and to extract the absolute humidity change rate.

[0023] The implicit thermodynamic identification module is used to output frequency commands with step pulses to the compressor within a specific period, and to calculate the implicit liquid phase buffer coefficient inside the system based on the transient response slope fed back by the exhaust temperature sensor.

[0024] The dew point offset optimization module receives output data from the humid air analysis module and the implicit thermodynamic identification module, respectively, to calculate the target dew point offset and generate the target evaporation temperature required for inner loop control based on the dew point temperature.

[0025] The sensible heat ratio decoupling control module is used to calculate the actual sensible heat ratio under the current operating conditions based on the ratio of the return air temperature change rate to the absolute humidity decrease rate, and outputs the target speed command of the indoor fan based on the deviation.

[0026] The dual-boundary switching control module is used to adjust the compressor's basic operating frequency based on the deviation between the actual evaporation temperature and the target evaporation temperature, and to control the opening of the electronic expansion valve based on the working range of suction superheat and exhaust superheat.

[0027] This embodiment also provides an enhanced air-source heat pump dehumidification method suitable for high-humidity environments. This method includes acquiring indoor environmental state parameters and calculating humid aerodynamic parameters. The microcontroller performs environmental parameter acquisition and continuous calculation of implicit thermodynamic parameters through its internal humid air analysis module, extracting state variables including the absolute humidity change rate as the data basis for system load boundary assessment.

[0028] The humid air analysis module receives return air temperature and relative humidity data from indoor temperature and humidity sensors. The microcontroller uses its built-in Anthony equation to calculate the saturated water vapor partial pressure at the current return air temperature. The specific calculation formula is as follows: ; In the formula, This is the partial pressure of saturated water vapor; Return air temperature; , , This refers to the Anthony constant. The specific value of the Anthony constant and the analog-to-digital conversion process of the temperature and humidity sensor can be determined by those skilled in the art through conventional table lookup or setting based on different temperature measurement ranges and hardware circuits. The specific implementation methods are well-known in the field and will not be elaborated upon here.

[0029] Based on the physical definition of relative humidity, the microcontroller calculates the actual water vapor partial pressure. The specific calculation formula is as follows: ; In the formula, This represents the actual partial pressure of water vapor. This refers to the relative humidity of the return air.

[0030] The humid air analysis module infers the dew point temperature based on the actual water vapor partial pressure. The microcontroller derives the air dew point temperature by calling the inverse transformation of the Anthony equation. The specific calculation formula is as follows: ; In the formula, The dew point temperature is the temperature of the return air. The microcontroller stores the calculated dew point temperature in a register as a physical reference for generating the target evaporation temperature.

[0031] The microcontroller calculates the mass of water vapor contained in a unit mass of dry air, i.e., the absolute moisture content, based on the local atmospheric pressure and the actual water vapor partial pressure. The specific calculation formula is as follows: ; In the formula, This refers to the absolute moisture content; The system defaults to local atmospheric pressure or can be input from an external barometer. It is an approximate constant conversion coefficient representing the ratio of the molecular weight of water vapor to the molecular weight of dry air.

[0032] In the implementation of obtaining the absolute humidity change rate, to support the summary of the change rate extraction function in the claims, the lower-level implementation features adopt a control algorithm combining digital filtering and discrete differential. The microcontroller establishes a time series queue of continuously sampled absolute humidity data. The microcontroller executes a first-order backward differential algorithm with low-pass filtering to eliminate the interference of high-frequency sampling noise on the derivative calculation. The specific calculation formula is as follows: ; In the formula, For the current number The absolute humidity change rate for each sampling period; This represents the absolute humidity change rate in the previous period; This represents the absolute moisture content for the current cycle. This represents the absolute moisture content of the previous cycle. The discrete control cycle step size set for the microcontroller; These are first-order digital filter coefficients, with values ​​greater than zero and less than one.

[0033] The microcontroller converts the directly acquired temperature and humidity scalar parameters into moist aerodynamic vector data. The moist air analysis module then transmits the output dew point temperature and absolute humidity change rate to the subsequent control module.

[0034] The dehumidification enhancement method provided in this embodiment includes an implicit system thermodynamic identification step based on low-frequency step excitation. The microcontroller executes an active detection program through its internal implicit thermodynamic identification module to assess the degree of liquid refrigerant accumulation inside the gas-liquid separator without adding a liquid level sensor.

[0035] The microcontroller triggers a detection cycle and suspends the compressor frequency control loop during this cycle, injecting a low-frequency step pulse into the variable frequency compressor. To prevent the detection signal from being negatively canceled out by the system's conventional proportional-integral controller, the microcontroller sets a specific detection cycle. The duration of this detection cycle is configured to be greater than the thermal time constant of the exhaust temperature sensor and less than the time required for the overall system refrigeration cycle to reach a new steady-state equilibrium, ensuring that the exhaust side exhibits a true transient thermodynamic response unaffected by the sensor's low-pass filtering physical effect. At the moment the detection program is triggered, the microcontroller temporarily suspends the outer-loop frequency regulation program of the variable frequency compressor, locking the current base operating frequency. The microcontroller superimposes a specific frequency change onto the base operating frequency, continuously outputting a command frequency with a positive step pulse to the variable frequency compressor. The specific calculation formula is as follows: ; In the formula, To detect the command frequency of the variable frequency compressor within the detection cycle; This is the start time that triggers the detection procedure; The base operating frequency is locked at the initial moment; The preset frequency step pulse amplitude for the microcontroller; The current running time; and satisfying ; The set detection cycle duration.

[0036] The microcontroller extracts the transient rise slope of exhaust superheat within the detection cycle. The implicit thermodynamic identification module receives temperature data from the exhaust temperature sensor and the condenser tube temperature sensor in real time and calculates the difference between them as the real-time exhaust superheat. Based on the physical characteristics of refrigerant two-phase flow, the increase in liquid refrigerant inside the gas-liquid separator leads to a greater overall system thermal inertia. The endothermic effect of liquid refrigerant evaporation slows down the response of exhaust superheat to compressor frequency increases. The microcontroller extracts the exhaust superheat data sequence within a preset time window. To eliminate the response dead zone caused by inherent sensor delays and refrigerant pipeline transmission delays, the microcontroller sets the effective data extraction window to [missing information]. ,in A preset dead-time constant is used to eliminate the initial unresponsive phase caused by the physical transmission delay of the control signal and the thermal conduction delay of the sensor. The microcontroller uses a least-squares algorithm to linearly fit the exhaust superheat sequence within this time window and extract the transient rise slope. The specific calculation formula is as follows: ; In the formula, The transient rise slope of the exhaust superheat; This refers to the real-time calculation of exhaust superheat. For the specific discrete calculation procedure of the slope of the least squares fitted line, those skilled in the art can perform matrix algebra operations or iterative solutions based on historical sampling points. The specific implementation logic is well-known in the field and will not be elaborated upon here.

[0037] The microcontroller calculates the implicit liquid-phase buffer coefficient and restores the closed-loop control of the system. The microcontroller establishes calculation logic between the transient rise slope of the exhaust superheat and the refrigerant buffer capacity within the system, calculating the implicit liquid-phase buffer coefficient that characterizes the level safety. The specific calculation formula is as follows: ; In the formula, This is the implicit liquid phase buffer coefficient; This is the reference rising slope constant when there is no liquid refrigerant accumulation inside the gas-liquid separator under calibration conditions. This reference rising slope constant is obtained from the test and calibration under standard liquid-free conditions before the system leaves the factory and is pre-stored in the non-volatile memory of the microcontroller.

[0038] Reference slope constant The value was obtained by taking the average value of multiple tests under the condition that the system is running stably and there is no liquid refrigerant in the gas-liquid separator. Its error range is controlled within ±5%.

[0039] The microcontroller normalizes the calculated implicit liquid buffer coefficient. A lower transient rise slope results in a calculated implicit liquid buffer coefficient closer to one, indicating a large accumulation of liquid refrigerant inside the gas-liquid separator, high overall system thermal inertia, and a potential risk of overflow into the compressor suction port. At the end of the detection cycle, the microcontroller actively cancels the frequency step pulse command and restores the variable frequency compressor's normal frequency regulation program. At any point during the above detection cycle, if the real-time calculated exhaust superheat falls below the set bottom-level safety threshold, the microcontroller will forcibly interrupt the detection cycle, stop outputting step pulses, and directly trigger the system's anti-liquid slugging protection program. The implicit thermodynamic identification module transmits the calculated implicit liquid buffer coefficient to subsequent control modules for constraint optimization.

[0040] The dehumidification enhancement method provided in this embodiment includes a dew point offset optimization step constrained by buffer boundaries. The microcontroller, through its internal dew point offset optimization module, calculates the target evaporation temperature required for subsequent control based on the environmental load demand and the refrigerant safety boundary.

[0041] The microcontroller calculates the baseline dew point offset. The dew point offset optimization module receives the return air relative humidity and absolute humidity change rate from the humid air analysis module. The microcontroller, combined with the user-defined target relative humidity, calculates the baseline dew point offset based on the static deviation of the current relative humidity and the rate of change of the absolute humidity, without considering the physical limitations of the refrigerant cycle. The specific calculation formula is as follows: ; In the formula, The base dew point offset; The relative humidity of the return air; Set the relative humidity for the target; This represents the absolute humidity change rate. This is the proportional gain coefficient used to respond to static humidity deviations and includes a conversion factor that converts the humidity deviations to the dimensions of temperature. The differential gain coefficient is used to respond to the dynamic rate of change in absolute humidity and includes the corresponding dimension conversion factor. The specific values ​​of the proportional gain coefficient and the differential gain coefficient can be preset by those skilled in the art using conventional control parameter tuning methods. The specific implementation methods are well-known in the field and will not be elaborated upon here.

[0042] The microcontroller calculates and optimizes the dew point offset. It extracts the implicit liquid phase buffer coefficient from the implicit thermodynamic identification module and incorporates this coefficient as a safety boundary factor into the offset calculation logic. When the indoor humidity deviation is large, the baseline dew point offset increases, causing the target evaporation temperature to be set too low, which in turn leads to refrigerant two-phase loss and compressor liquid slugging risks. The microcontroller dynamically reduces the baseline dew point offset based on the level of liquid refrigerant accumulation within the system. The specific calculation formula is as follows: ; In the formula, To optimize the dew point offset; This is the implicit liquid phase buffer coefficient; This is the liquid phase buffer penalty coefficient, whose value range is configured to be greater than zero and less than or equal to one. This coefficient is a constant that is preset and stored by the system. When the implicit liquid phase buffer coefficient approaches one, the product term in the formula decreases, the microcontroller reduces the base dew point offset, and limits the target evaporation temperature from being set to a lower value.

[0043] The microcontroller generates the target evaporation temperature. Based on the stored dew point temperature of the return air and the optimized dew point offset obtained above, the microcontroller calculates the target evaporation temperature required for subsequent control. The specific calculation formula is as follows: ; In the formula, The target evaporation temperature; This refers to the dew point temperature of the return air.

[0044] After calculating the target evaporation temperature, the microcontroller writes it into the associated register for compressor frequency and electronic expansion valve opening control. When the optimized dew point offset decreases, the target evaporation temperature generated by the microcontroller approaches the dew point temperature of the return air. The increase in the target evaporation temperature causes the microcontroller to control the compressor and electronic expansion valve to reduce the refrigerant circulation flow rate, thereby reducing the accumulation of liquid refrigerant inside the gas-liquid separator, thus maintaining a balance between system dehumidification operation and refrigerant circulation safety.

[0045] The dehumidification enhancement method provided in this embodiment includes an air-side sensible heat ratio decoupling control step. The microcontroller, through its internal sensible heat ratio decoupling control module, adjusts the speed of the indoor fan according to the proportional relationship between the rate of change of indoor temperature and the rate of change of absolute humidity, in order to match the indoor sensible heat and latent heat load requirements.

[0046] The sensible heat ratio decoupling control module receives the return air temperature from the indoor temperature and humidity sensor. The microcontroller extracts the return air temperature data and uses a first-order backward differential algorithm with low-pass filtering to calculate the rate of change of the return air temperature. The specific calculation formula is as follows: ; In the formula, For the current number The rate of change of return air temperature in each sampling period; This represents the rate of change of return air temperature in the previous cycle; The return air temperature for the current cycle; This is the return air temperature from the previous cycle; The discrete control cycle step size set for the microcontroller; These are first-order digital filter coefficients, with values ​​greater than zero and less than one.

[0047] The microcontroller calculates the system's current actual apparent-to-latent ratio based on the return air temperature change rate and the absolute humidity change rate output by the humid air analysis module. The specific calculation formula is as follows: ; In the formula, This represents the actual potential-to-potential ratio; The specific heat capacity of dry air at constant pressure; The latent heat of vaporization of water in its current state; This represents the rate of change of return air temperature during the current cycle. This indicates the absolute value of the rate of change of return air temperature. For the current number The absolute humidity change rate for each sampling period; This represents the absolute value of the absolute humidity change rate. For the specific values ​​of the isobaric specific heat capacity and latent heat of vaporization of dry air, those skilled in the art can routinely look up or set them based on engineering thermodynamic property parameter tables. The specific implementation methods are well-known techniques in this field and will not be elaborated upon here.

[0048] The microcontroller calculates the target indicative-to-latency ratio based on the current return air condition and the target set condition. The specific calculation formula is as follows: ; In the formula, The target is the ratio of apparent potential to actual potential. Return air temperature; Set the target temperature; This refers to the absolute moisture content; Set the absolute moisture content for the target; This is the specific heat capacity of dry air at constant pressure. This refers to the latent heat of vaporization of water. Based on the user-input target relative humidity and target temperature, the microcontroller uses the Anthony equation in the humid air analysis module to calculate the target absolute humidity.

[0049] After calculating the actual and target apparent power ratios, the microcontroller calculates the speed adjustment of the indoor fan. The microcontroller uses a proportional-integral (PI) control algorithm to calculate this speed adjustment. The specific calculation formula is as follows: ; In the formula, This refers to the speed adjustment of the indoor fan; This represents the actual potential-to-potential ratio; The target is the ratio of apparent potential to actual potential. This is the proportional gain coefficient for fan speed; This is the integral gain coefficient for the fan speed. From the start of self-control operation to the current number The cumulative summation term of the deviation between the actual and target latent ratios within each sampling period. This proportional gain coefficient and integral gain coefficient include a conversion factor that converts the dimensionless deviation of the ratio into the dimension of rotational speed.

[0050] The microcontroller updates the target speed command for the indoor fan based on the speed adjustment. The specific calculation formula is as follows: ; In the formula, The target speed command; This is the current operating speed of the indoor fan; This refers to the speed adjustment of the indoor fan.

[0051] The microcontroller converts the generated target speed command into a pulse width modulation signal and outputs it to the indoor fan. When the actual sensible heat-to-latent heat ratio is greater than the target sensible heat-to-latent heat ratio, the system currently outputs more sensible heat cooling capacity while the latent heat dehumidification capacity is insufficient. Based on the above calculation logic, the microcontroller outputs a positive speed adjustment amount to reduce the target speed command. When the indoor fan speed decreases, the residence time of air on the surface of the indoor heat exchanger increases, the air dehumidification rate increases, the system's actual sensible heat-to-latent heat ratio decreases and approaches the target sensible heat-to-latent heat ratio, thus achieving control of sensible heat and latent heat on the air side.

[0052] The dehumidification enhancement method provided in this embodiment includes a refrigerant-side dual superheat adaptive boundary switching control step. The microcontroller, through its internal electronic expansion valve control module, switches between the suction superheat control boundary and the discharge superheat control boundary based on the accumulation state of the liquid refrigerant inside the system, thereby adjusting the opening degree of the electronic expansion valve.

[0053] The microcontroller acquires refrigerant-side operating status parameters and calculates the actual superheat. The microcontroller receives temperature data from the suction temperature sensor, discharge temperature sensor, and heat exchanger tube temperature sensor. Based on this temperature data, the microcontroller calculates the actual suction superheat and the actual discharge superheat, respectively. The specific calculation formulas are as follows: ; ; In the formula, This represents the actual intake superheat. This refers to the compressor's suction temperature. This refers to the evaporation temperature of the indoor heat exchanger. This represents the actual exhaust superheat. This refers to the compressor's exhaust temperature. This refers to the condensing temperature of the outdoor heat exchanger.

[0054] The microcontroller calculates the adaptive weighted control deviation. The microcontroller employs weighted calculation logic based on an implicit liquid phase buffer coefficient to switch the control boundary. Under normal load operation, the system uses the suction superheat as the control boundary. When enhanced dehumidification leads to the accumulation of liquid refrigerant in the gas-liquid separator, increasing the implicit liquid phase buffer coefficient, the microcontroller gradually shifts the weight of the control boundary towards the exhaust superheat to limit the overflow of liquid refrigerant. The microcontroller calculates the comprehensive control deviation based on this logic. The specific calculation formula is as follows: ; In the formula, For the current number The overall control deviation of each sampling period; This is the implicit liquid phase buffer coefficient; For the current number Actual intake superheat in each sampling cycle; The target intake superheat is a constant that is preset and stored in the system. For the current number The actual exhaust superheat in each sampling period; The target exhaust superheat is a constant that is preset and stored in the system. This is a constant matching coefficient for converting exhaust superheat to intake superheat, which is determined by the system calibration test before leaving the factory.

[0055] The microcontroller calculates the opening adjustment of the electronic expansion valve and outputs the target opening command. The microcontroller uses a proportional-integral (PI) control algorithm to handle the overall control deviation and calculates the opening adjustment of the electronic expansion valve. The specific calculation formula is as follows: ; In the formula, This refers to the opening adjustment amount of the electronic expansion valve; For the current number The overall control deviation of each sampling period; This is the proportional gain coefficient for the opening degree of the electronic expansion valve; The integral gain coefficient for the opening degree of the electronic expansion valve; From the start of self-control operation to the current number The cumulative summation term of the comprehensive control deviation within each sampling period. For the specific values ​​of the proportional gain coefficient and integral gain coefficient of the electronic expansion valve opening, those skilled in the art can preset the system according to conventional control parameter tuning methods. The specific implementation method is well-known in the field and will not be elaborated here.

[0056] The microcontroller updates the target opening command of the electronic expansion valve based on the calculated opening adjustment. The specific calculation formula is as follows: ; In the formula, The target opening instruction; This represents the current opening degree of the electronic expansion valve; This refers to the opening adjustment amount of the electronic expansion valve.

[0057] The microcontroller converts the generated target opening command into a pulse control signal to drive the stepper motor and outputs it to the drive circuit of the electronic expansion valve. When the implicit liquid phase buffer coefficient increases, the microcontroller switches the system safety boundary by increasing the weight of the exhaust superheat deviation in the control logic. If the actual exhaust superheat is less than the target exhaust superheat, the overall control deviation calculated above by weighting will decrease or even become negative. Based on this negative deviation, the microcontroller outputs a reduced opening adjustment amount, reducing the opening of the electronic expansion valve to reduce the refrigerant circulation and ensure the safe operation of the compressor during dehumidification.

[0058] This embodiment describes the system control logic and signal transmission process when the indoor humidity is moderate and the intake superheat is normal.

[0059] The microcontroller collects environmental parameters and determines the system's operating condition. The humid air analysis module receives the return air temperature and relative humidity from the indoor temperature and humidity sensors. The microcontroller calculates the deviation between the current return air relative humidity and the target set relative humidity. When this deviation is within the preset moderate humidity range, and the implicit liquid buffer coefficient output by the implicit thermodynamic identification module is zero, the microcontroller determines that the system is in normal dehumidification mode. Under this mode, there is no liquid refrigerant accumulation inside the gas-liquid separator, and the refrigerant circulation is within safe physical boundaries.

[0060] The microcontroller performs dew point offset optimization calculation. The dew point offset optimization module receives data from the humid air analysis module and calculates the base dew point offset. Since the implicit liquid phase buffer coefficient is zero at this point, the liquid phase buffer constraint term in the calculation logic has no effect, and the optimized dew point offset equals the base dew point offset. Based on the return air dew point temperature and the optimized dew point offset, the microcontroller calculates the target evaporation temperature. The microcontroller writes this target evaporation temperature into the compressor frequency control register. The variable frequency compressor maintains its base operating frequency based on the target evaporation temperature, outputting a stable refrigerant mass flow rate.

[0061] The microcontroller performs sensible heat ratio matching control on the air side. The sensible heat ratio decoupling control module extracts the return air temperature change rate and absolute humidity change rate. Under normal dehumidification conditions, the ratio of indoor sensible heat load to latent heat load is relatively stable. The deviation between the actual sensible heat ratio calculated by the microcontroller and the target sensible heat ratio is within the set dead zone. The speed adjustment output of the microcontroller approaches zero, and the indoor fan maintains its current set speed. In this state, the indoor heat exchanger surface maintains a stable amount of air moisture removal, and the actual latent heat dehumidification capacity of the system meets the indoor dehumidification requirements. The microcontroller monitors the current actual latent heat dehumidification capacity through enthalpy difference calculation logic; the specific calculation formula is as follows: ; In the formula, This represents the actual latent heat dehumidification capacity. The density of dry air; The current air volume flow rate of the indoor fan is obtained by the microcontroller based on the current speed of the indoor fan and the pre-stored fan characteristic curve. The latent heat of vaporization of water in its current state; The absolute humidity content of the return air is calculated by the humid air analysis module based on data collected by the return air temperature and humidity sensor. The absolute moisture content of the outlet air is calculated by a humid air analysis module based on data collected by the outlet air temperature and humidity sensor. The specific values ​​for dry air density and latent heat of vaporization can be obtained by those skilled in the art through conventional table lookup based on engineering thermodynamic property parameters; the specific implementation method is well-known in the field and will not be elaborated here.

[0062] The microcontroller controls the opening of the electronic expansion valve on the refrigerant side. It extracts the implicit liquid phase buffer coefficient and substitutes it into the calculation logic of the adaptive weighted control deviation. Since the implicit liquid phase buffer coefficient is zero under normal dehumidification conditions, the weight of exhaust superheat in the control logic is eliminated, and the system control boundary is completely switched to suction superheat. The specific calculation formula is as follows: ; In the formula, For the current number The overall control deviation of each sampling period; For the current number Actual intake superheat in each sampling cycle; The target intake superheat is a constant that is preset and stored in the system.

[0063] The microcontroller calculates the opening adjustment of the electronic expansion valve using a proportional-integral (PI) control algorithm based on the aforementioned comprehensive control deviation. The electronic expansion valve maintains a preset throttling opening according to the updated target opening command, ensuring that the actual suction superheat follows the target suction superheat. Under the current control state, the indoor heat exchanger maintains a stable heat exchange area, and the system outputs cooling and dehumidification capacity while ensuring the safe operation of the compressor.

[0064] The microcontroller acquires the operating status and triggers implicit thermodynamic identification. The microcontroller obtains the return air relative humidity and actual suction superheat through indoor temperature and humidity sensors and pipe temperature sensors. Under high humidity and high load conditions, the indoor latent heat load is large, and the initial target evaporation temperature output by the microcontroller is low, causing the actual suction superheat to continuously decrease and approach zero. When the microcontroller determines that the actual suction superheat is less than the system's preset safety threshold (this safety threshold is a constant preset and stored by the system), the microcontroller triggers the internal implicit system thermodynamic identification module. The microcontroller injects a frequency step pulse into the variable frequency compressor, extracts the transient rise slope of the exhaust superheat, and calculates the implicit liquid phase buffer coefficient. Because a large amount of liquid refrigerant accumulates inside the gas-liquid separator at this time, the system's thermal inertia increases, and the calculated implicit liquid phase buffer coefficient approaches one.

[0065] The microcontroller performs dew point offset reduction constrained by the buffer boundary. The dew point offset optimization module receives the implicit liquid phase buffer coefficient, which approaches one. The microcontroller executes the calculation logic to optimize the dew point offset. As the implicit liquid phase buffer coefficient increases, the product term in the calculation logic decreases, and the microcontroller reduces the base dew point offset. Based on the reduced optimized dew point offset, the microcontroller generates a target evaporation temperature, which is close to the dew point temperature of the return air. The microcontroller writes this target evaporation temperature into the associated register of the compressor frequency control, controlling the variable frequency compressor to reduce its operating frequency.

[0066] The microcontroller implements lower limit constraint control for the fan speed. The sensible heat ratio decoupling control module calculates the indoor fan speed adjustment based on the deviation between the actual and target sensible heat ratios. Under high-load dehumidification requirements, the microcontroller continuously outputs speed adjustment to reduce the target speed command for the indoor fan. To prevent excessively low fan speeds from causing frost buildup on the indoor heat exchanger surface, the microcontroller incorporates lower limit constraint logic to calculate the final target speed command. The specific calculation formula is as follows: ; In the formula, The target speed command; This is the current operating speed of the indoor fan; This refers to the speed adjustment of the indoor fan; This is the preset minimum speed constant for preventing frost formation in the indoor fan. The specific value of this minimum speed constant can be determined by those skilled in the art through routine calibration tests based on the physical structure of the heat exchanger and the aerodynamic characteristics of the fan. The specific implementation method is well-known in the field and will not be elaborated upon here.

[0067] The microcontroller switches the refrigerant-side control boundary. It substitutes an implicit liquid-phase buffer coefficient, approaching one, into the calculation logic of the electronic expansion valve control module. Because the implicit liquid-phase buffer coefficient approaches one, the weighting coefficient of the deviation term between the actual and target suction superheat is reduced to near zero, and the system control boundary switches to the actual discharge superheat. The microcontroller then calculates the overall control deviation at this point. The specific calculation formula is as follows: ; In the formula, For the current number The overall control deviation of each sampling period; This is a constant matching coefficient for converting exhaust superheat to intake superheat, which is determined by the system calibration test before leaving the factory. For the current number The actual exhaust superheat in each sampling period; The target exhaust superheat is a constant that is preset and stored in the system.

[0068] Based on the aforementioned comprehensive control deviation, the microcontroller uses a proportional-integral (PI) control algorithm to calculate the adjustment amount of the electronic expansion valve opening. When the amount of liquid refrigerant accumulated in the gas-liquid separator is large, the actual exhaust superheat decreases and becomes less than the target exhaust superheat, resulting in a negative comprehensive control deviation calculated by the microcontroller. Based on this negative deviation, the microcontroller reduces the opening of the electronic expansion valve, thereby reducing the refrigerant circulation flow rate of the system. When the actual suction superheat approaches zero, the system maintains closed-loop control based on feedback from the actual exhaust superheat data, driving the liquid refrigerant inside the gas-liquid separator to evaporate more rapidly. This prevents the microcontroller from triggering the compressor shutdown protection program and maintains the system's dehumidification operation.

[0069] This embodiment describes the control logic and signal transmission process by which the microcontroller performs priority forced intervention on each underlying actuator and subsequent interruption recovery when the implicit liquid phase buffer coefficient reaches the system calculation limit or the actual exhaust superheat is less than the exhaust superheat limit threshold.

[0070] The microcontroller performs conditional checks for liquid slugging protection. It monitors in real-time the implicit liquid phase buffer coefficient output by the implicit system thermodynamic identification module and the actual exhaust superheat fed back by the refrigerant-side sensors. When the system is under high humidity and high load conditions, the amount of liquid refrigerant accumulated inside the gas-liquid separator may exceed its physical volume limit, causing a large number of unevaporated droplets to enter the compressor's compression chamber with the suction airflow. The microcontroller determines whether the system faces liquid slugging risk based on set limit conditions; the specific judgment logic expression is as follows: ; In the formula, This is the implicit liquid phase buffer coefficient; This represents the actual exhaust superheat. The exhaust superheat limit threshold is a constant preset and stored by the system. When the implicit liquid phase buffer coefficient is greater than or equal to one, or the actual exhaust superheat is less than the exhaust superheat limit threshold, the microcontroller determines that the anti-liquid hammer protection condition is met and triggers the interrupt intervention program.

[0071] The microcontroller interrupts the conventional closed-loop control algorithm and outputs forced intervention commands to each actuator according to preset hardware priorities. The microcontroller executes the priority response and forced intervention logic. It skips the calculation steps of the dew point offset optimization module and the sensible heat ratio decoupling control module, directly writing the target control command into the control registers of each actuator. Based on response speed and the degree of thermodynamic influence, the microcontroller sequentially applies forced parameter settings to the electronic expansion valve, variable frequency compressor, and indoor fan. The specific forced setting formula is as follows: ; ; ; In the formula, The target opening command for the electronic expansion valve; This is the minimum safe opening constant of the electronic expansion valve, which is a constant preset and stored by the system. The target operating frequency of the variable frequency compressor; This is the safety frequency constant for preventing liquid slugging in the variable frequency compressor; it is a constant that is preset and stored in the system. The target speed command for the indoor fan; This is the maximum speed constant of the indoor fan, which is a constant preset and stored by the system.

[0072] Based on the aforementioned forced formula, the microcontroller controls the electronic expansion valve to reduce its opening to the minimum safe opening constant to block excessive refrigerant supply to the indoor heat exchanger; simultaneously, it controls the variable frequency compressor to reduce its speed to the anti-liquid slugging safe frequency constant, reducing pressure pulsation and refrigerant mass flow rate in the suction chamber; and it controls the indoor fan to increase its speed to the maximum speed constant, increasing the heat input to the air side of the indoor heat exchanger and driving the residual liquid refrigerant in the pipes to evaporate more quickly.

[0073] The microcontroller executes interrupt recovery and smooth transition logic. After a forced intervention command is issued, the microcontroller continuously monitors the recovery trend of the actual exhaust superheat. To avoid system oscillation caused by frequent switching between intervention and normal states, the microcontroller introduces a one-way hysteresis interval as a recovery judgment condition. The specific judgment logic expression is as follows: ; In the formula, This represents the actual exhaust superheat. The exhaust superheat recovery threshold is a constant preset and stored by the system, and it is greater than the exhaust superheat limit threshold. When the actual exhaust superheat exceeds the exhaust superheat recovery threshold, and this state is maintained for a longer period than the delay confirmation period set by the microcontroller (which is a time constant preset and stored by the system), the microcontroller determines that the system is out of the risk of liquid slugging. The microcontroller exits the interrupt intervention program, clears the historical accumulated terms of the internal proportional-integral regulator to zero, and resumes the dew point offset optimization calculation and adaptive boundary switching control. The specific values ​​of the exhaust superheat limit threshold, the exhaust superheat recovery threshold, and the safety constants of each actuator can be conventionally set by those skilled in the art based on the compressor's mechanical characteristics and system reliability testing. The specific implementation methods are well-known in the field and will not be elaborated here.

[0074] This embodiment provides a dehumidification enhancement control system, which is integrated into a microcontroller. By mapping the aforementioned control methods to corresponding virtual functional modules, the system executes data acquisition, logical judgment, and command output at the underlying hardware level. The dehumidification enhancement control system includes a humid air analysis module, an implicit thermodynamic identification module, a dew point offset optimization module, a sensible heat ratio decoupling control module, an electronic expansion valve control module, and a liquid hammer protection module.

[0075] The humid air analysis module and the implicit thermodynamic identification module are configured as input terminals for data acquisition and condition assessment. The humid air analysis module calculates the dew point temperature based on return air condition data collected by indoor temperature and humidity sensors. The implicit thermodynamic identification module calculates the implicit liquid phase buffer coefficient based on the frequency step pulse injected by the variable frequency compressor and the slope of the exhaust superheat response. These modules then transmit the calculated environmental parameters and refrigerant-side condition characteristics to the subsequent control calculation module.

[0076] The dew point offset optimization module, sensible heat ratio decoupling control module, and electronic expansion valve control module are configured as the core of conventional closed-loop control. The dew point offset optimization module calculates the target evaporation temperature based on the dew point temperature and the implicit liquid phase buffer coefficient, and converts this to generate the target operating frequency of the variable frequency compressor. The sensible heat ratio decoupling control module calculates the target speed command for the indoor fan based on the deviation between the actual and target sensible heat ratios. The electronic expansion valve control module performs boundary switching between suction superheat and exhaust superheat based on the implicit liquid phase buffer coefficient, and calculates the target opening command for the electronic expansion valve. These three modules operate synchronously and in parallel to generate the conventional control command matrix for the system under normal operating conditions.

[0077] The liquid hammer protection module is configured as the highest priority safety intervention node in system operation. The virtual functional modules within the microcontroller switch system control via Boolean status flags and execute integrated output mapping logic. The specific judgment logic formula for generating the Boolean status flags based on the implicit liquid phase buffer coefficient and the actual exhaust superheat is as follows: ; In the formula, The Boolean status flag output by the liquid impact protection module; This is the implicit liquid phase buffer coefficient; This represents the actual exhaust superheat. The exhaust superheat limit threshold is a constant that is preset and stored in the system. The exhaust superheat recovery threshold is a constant that is preset and stored in the system. The duration during which the actual exhaust superheat exceeds the exhaust superheat recovery threshold is accumulated by a timer inside the microcontroller. The delayed confirmation period is a time constant that is preset and stored by the system.

[0078] Based on the Boolean status flags output by the liquid-proof protection module, the microcontroller performs a weighted mapping between the conventional control command matrix and the forced intervention command matrix, outputs the final integrated control command matrix, and writes it into the control registers of each underlying actuator. The specific calculation formula is as follows: ; In the formula, For the current number A comprehensive control command matrix for each sampling period; The Boolean status flag output by the liquid impact protection module; For the current number A standard control command matrix for each sampling period; This is a pre-defined matrix of mandatory intervention instructions.

[0079] For the internal elements of the conventional control command matrix and the forced intervention command matrix, their matrix structure corresponds to the control parameters of each actuator. The specific expansion relationship is as follows: ; ; In the formula, The current output of the conventional closed-loop control algorithm The target operating frequency of the variable frequency compressor in each sampling period; The current output of the conventional closed-loop control algorithm The target speed command for the indoor fan in each sampling period; The current output of the conventional closed-loop control algorithm The target opening command of the electronic expansion valve for each sampling cycle; This is the safety frequency constant for preventing liquid slugging in the variable frequency compressor; it is a constant that is preset and stored in the system. This is the maximum speed constant of the indoor fan, which is a constant preset and stored by the system. This is the minimum safe opening constant of the electronic expansion valve, which is a constant preset and stored by the system.

[0080] In the modular operation mechanism of the dehumidification enhancement control system, each virtual functional module works collaboratively within a unified clock cycle. When the system is within the safety boundary, the Boolean state flag remains at zero, and the system is controlled by the matrix elements output by the dew point offset optimization module, the sensible heat ratio decoupling control module, and the electronic expansion valve control module. When the anti-liquid hammer boundary is triggered, the Boolean state flag becomes one, the microcontroller's control logic switches to the anti-liquid hammer protection module, and the forced intervention instruction matrix directly overrides the conventional control instruction matrix and takes over the system operation. Under this logical architecture, those skilled in the art can use a modular software code structure to compile and solidify the above control logic into the microcontroller's memory. The specific underlying code writing rules and register address allocation mechanism are well-known technologies in the field and will not be elaborated here.

[0081] This embodiment provides an electronic device and a computer-readable storage medium. The electronic device is specifically configured as a microcontroller for an air conditioner or a separate control motherboard, which integrates a processor and a memory communicatively connected to the processor. The memory stores computer program instructions executable by the processor. By reading and executing these program instructions, the processor implements various control actions in the aforementioned dehumidification enhancement method, such as data acquisition, status identification, optimization calculation, and forced intervention.

[0082] The memory, as a specific implementation of a computer-readable storage medium, internally includes a non-volatile storage area for storing the aforementioned control logic algorithms, and a volatile storage area for caching runtime data. Specific underlying physical forms of non-volatile storage media include, but are not limited to, electrically erasable programmable read-only memory (EEPROM), flash memory (including NAND and NOR flash), read-only memory (ROM), magnetic random access memory (MRAM), or ferroelectric random access memory (FRAM). Specific underlying physical forms of volatile storage media include static random access memory (SRAM) or dynamic random access memory (DRAM). The aforementioned control logic, such as the humid air analysis module, implicit thermodynamic identification module, and liquid shock protection module, is converted into low-level machine code by the compiler and then burned into the non-volatile storage medium as firmware.

[0083] The processor is configured as a computational core that executes instructions from memory. The specific physical form of the processor includes a central processing unit (CPU), a microprocessor unit (MPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). During system operation, the processor retrieves the aforementioned control deviations and environmental parameters from memory via an internal bus and performs matrix multiplication and addition, as well as proportional-integral operations, in the arithmetic logic unit.

[0084] To ensure the timely effectiveness of the system's liquid-sinking protection under extreme operating conditions, the total computation cycle of the processor executing the aforementioned control program instructions is subject to strict real-time constraints. Within each sampling cycle, the processor must complete the entire computation chain from data acquisition to the output of the target control instruction. The specific logical judgment expression for the real-time constraint is as follows: ; In the formula, The total number of operation cycles for the processor to execute control program instructions; The total number of task subroutines controlled by the logic is determined by the compilation results of the software architecture; For the first The number of machine instructions contained in each task subroutine; To execute the first The average number of clock cycles required for a single machine instruction in a task subroutine; This is the core operating frequency of the processor, which is determined by the processor's hardware crystal oscillator configuration; The basic control sampling period of the system is a pre-set and stored time constant; This is the sum of communication transmission delays of each underlying actuator on the data bus, which is calculated from the system hardware bus baud rate and the communication protocol data frame length.

[0085] When the processor determines that the current system's instruction execution time meets the aforementioned real-time constraints, it ensures that the system can write the minimum safe opening constant and the anti-liquid slugging safe frequency constant into the corresponding hardware registers before the liquid refrigerant overflow causes a decrease in the actual exhaust superheat. For the processor's instruction pipeline architecture, memory physical addressing mechanism, and operating system task scheduling and allocation logic, those skilled in the art can perform conventional low-level hardware and software co-design based on the chip datasheet. The specific implementation methods are well-known technologies in the field and will not be elaborated upon here.

[0086] Specific application examples: Experimental platform and operating condition settings The experimental verification in this embodiment relies on a standard enthalpy difference laboratory environment. The test prototype is a variable frequency split-type air source heat pump with a rated cooling capacity of 5000W (2 horsepower). The initial environmental conditions set in the experiment simulate typical high humidity and high temperature climates such as the humid spring season or plum rain season: initial indoor return air temperature... =28℃, initial return air relative humidity =85%. The user-defined target operating parameters are: target set temperature. =26℃, target relative humidity =50%.

[0087] The comparative experiment was divided into two groups: Control group (using existing conventional control technology): The system relies solely on indoor temperature feedback to adjust the compressor frequency and maintain a constant target intake superheat (set to 5°C) to adjust the opening of the electronic expansion valve, while the indoor fan maintains a constant speed at medium speed.

[0088] Experimental group (using the dehumidification enhancement control technology of this invention): Activate the microcontroller's internal modules for humid air analysis, implicit thermodynamic identification, dew point optimization, sensible heat ratio decoupling, and dual-boundary switching control.

[0089] Detailed data recording of the operational process (experimental group) After system startup, it enters the high-load dehumidification phase. The microcontroller's control logic evolves as follows: Phase 1: Humid Air Analysis and Optimization Start-up When the system starts up, the microcontroller collects the initial temperature and humidity, and the humid air analysis module calculates the current return air dew point temperature. =25.2℃. Because the initial relative humidity (85%) is much higher than the set value (50%), the dew point offset optimization module calculates a large base dew point offset. =12℃. No liquid refrigerant accumulation was detected initially (implicit liquid buffer coefficient). ), generating a lower target evaporation temperature =13.2℃, control the variable frequency compressor to run at high frequency.

[0090] Phase 2 of Operation: Thermodynamic Identification and Boundary Switching After 15 minutes of operation, due to the large latent heat load indoors, a large amount of water vapor condenses in the indoor heat exchanger, and liquid refrigerant begins to accumulate inside the gas-liquid separator, resulting in an actual suction superheat. Temperatures dropped to 1°C.

[0091] The microcontroller triggers the implicit thermodynamic identification module, temporarily suspending the current frequency and injecting an amplitude of [value missing] into the variable frequency compressor. A frequency step pulse (duration 60 seconds).

[0092] The microcontroller extracts the transient rise slope of the exhaust superheat. Due to the buffering and endothermic effect of liquid refrigerant, calculations show that... =0.05℃ / s, far below the factory-specified slope without liquid reservoir. =0.20℃ / s. The microcontroller calculates the implicit liquid buffer coefficient. 0.75.

[0093] Phase 3: Decoupling and Safety Balance Control microcontroller will 0.75 Electronic expansion valve control boundary switching: The weight of exhaust superheat deviation is increased to 75%. The microcontroller generates a negative opening adjustment based on the actual exhaust superheat, reducing the electronic expansion valve opening from 300 steps to 220 steps.

[0094] Dew point offset constraint: Optimize dew point offset Forced to be reduced to 3°C, target evaporation temperature The temperature was increased to 22.2℃, and the compressor frequency decreased moderately.

[0095] Sensible heat ratio decoupling matching: The sensible heat ratio decoupling control module calculates that the current actual sensible heat ratio is too high, and outputs speed adjustment amount to control the indoor fan speed to decrease from 800RPM to the anti-frost lower limit constant of 600RPM, so as to prolong the air residence time.

[0096] After the above closed-loop adjustment, while maintaining the maximum dehumidification capacity, the actual exhaust superheat remains stable above 15°C, the liquid level in the gas-liquid separator stops rising, and the ultimate anti-liquid hammer shutdown protection is not triggered.

[0097] Comparison of experimental results and data analysis Based on the data sequence collected in the enthalpy difference laboratory, the operational results of the control group and the experimental group are compared as follows: Comparison of dehumidification efficiency and temperature and humidity control: After 30 minutes of operation, the control group system experienced persistently low intake superheat, triggering its built-in basic protection logic to drastically reduce the compressor's frequency or even shut it down to prevent liquid slugging. Consequently, after 60 minutes of operation, the indoor relative humidity only decreased to 70%, failing to reach the target humidity level.

[0098] After 60 minutes of operation, the indoor return air temperature of the experimental system (this invention) remained stable at 26.1℃, and the indoor relative humidity successfully decreased to 52%. The average condensation rate per unit time reached 2.8 kg / h, which is about 47% higher than that of the control group (1.9 kg / h during the effective operation period).

[0099] Comparison of compressor operation safety and reliability: In the control group, the actual exhaust superheat at the 25-minute mark was... A sudden drop, reaching a low of 8°C, indicates that trace amounts of liquid refrigerant have entered the compressor cavity, posing a serious risk of liquid slugging damage to the system. The experimental system relies on feedforward prediction and control boundary switching using an implicit liquid-phase buffer coefficient to measure the actual exhaust superheat throughout its entire lifespan. All are within the absolutely safe range of 15℃-25℃, achieving uninterrupted and stable operation under extreme high humidity conditions.

[0100] Figure 4 and Figure 5 The figure shows a comparison of indoor temperature and humidity evolution curves between existing control technologies and the control strategy of this invention under high humidity conditions. The relative humidity curve at the top of the figure indicates that both systems show a normal decreasing trend in indoor humidity during the initial operation. However, after approximately 15 minutes of operation, the system using the existing technology, when the relative humidity drops to around 70%, triggers the traditional anti-liquid slugging protection logic, resulting in a significant decrease in the system's dehumidification capacity. The humidity fluctuates within this range and struggles to decrease further. Simultaneously, the temperature comparison curve at the bottom of the figure shows that, due to the limited cooling output of the system, the indoor return air temperature of the existing technology deviates to around 26.5°C, failing to reach the target of 26°C. In contrast, the embodiment of this invention maintains stable cooling and dehumidification output throughout the entire operating cycle, with the indoor relative humidity decreasing steadily and ultimately remaining at the target value of 50%; simultaneously, the indoor return air temperature is also stably controlled at 26°C. The attached figures clearly demonstrate that this invention effectively overcomes the temperature and humidity control defects caused by the anti-liquid slugging protection in traditional air conditioners under high humidity conditions, thus improving the environmental regulation effect.

[0101] Figure 6The evolution and adaptive adjustment curves of the actual exhaust superheat and implicit liquid phase buffer coefficient in this embodiment of the invention are shown within the same operating cycle, further revealing the underlying principle of the aforementioned control effect. In the first 15 minutes of operation, due to the high initial latent heat load, some refrigerant fails to completely vaporize in the evaporator, causing the actual exhaust superheat to drop rapidly from 25°C and approach the safety baseline of 15°C. When this boundary is reached at the 15-minute mark, this invention does not directly reduce the compressor operating frequency but triggers the implicit thermodynamic identification mechanism. At this time, the implicit liquid phase buffer coefficient calculated by the microcontroller undergoes a step change (rising to 0.75) to quantitatively assess the current liquid phase boundary and liquid slugging risk level of the system. During the adjustment phase from 15 to 45 minutes, the system adaptively adjusts based on this coefficient, allowing the exhaust superheat to rise smoothly near the safety baseline, avoiding compressor liquid slugging; simultaneously, as excess liquid refrigerant in the system is gradually vaporized and consumed, the implicit liquid phase buffer coefficient shows a step-like decline (dropping to 0.40). After 45 minutes of operation, the system exited the high-load critical state, and the implicit liquid-phase buffer coefficient stabilized within the safe range of 0.10. The exhaust superheat also remained within a stable and safe range. This demonstrates that by introducing an implicit liquid-phase buffer coefficient, this invention can dynamically assess the liquid slugging resistance of the gas-liquid separator. While ensuring the safe operation of the compressor, it avoids unnecessary passive frequency reduction, effectively balancing liquid slugging safety with continuous dehumidification capability.

Claims

1. An enhanced dehumidification method for air-source heat pumps suitable for high-humidity environments, characterized in that, Includes the following steps: Acquire indoor environmental state parameters and calculate air dew point temperature, absolute moisture content and absolute humidity change rate, while also acquiring the actual suction superheat and actual discharge superheat on the refrigerant side. Within a set detection period, a frequency command with a step pulse is injected into the variable frequency compressor to extract the transient rise slope of the actual exhaust superheat, and based on this, the implicit liquid phase buffer coefficient characterizing the degree of liquid refrigerant accumulation inside the gas-liquid separator is calculated. Based on the calculated dew point temperature and absolute humidity change rate, and by introducing the implicit liquid phase buffer coefficient as a safety boundary coefficient, the target evaporation temperature is calculated to adjust the basic operating frequency of the variable frequency compressor. The actual apparent moisture ratio under the current operating conditions is calculated based on the ratio of the return air temperature change rate to the absolute humidity change rate. The target apparent moisture ratio is calculated by combining the absolute humidity and the set parameters. Based on the deviation between the actual apparent moisture ratio and the target apparent moisture ratio, the target speed command of the indoor fan is output to control the indoor fan speed. Based on the implicit liquid phase buffer coefficient, a weighted calculation is performed between the actual intake superheat control boundary and the actual exhaust superheat control boundary to obtain the comprehensive control deviation, and the opening of the electronic expansion valve is adjusted based on the comprehensive control deviation.

2. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, The calculation steps for the dew point temperature, absolute moisture content, and absolute humidity change rate of the air include: The saturated water vapor partial pressure at the current return air temperature is calculated using the Anthony equation, and the actual water vapor partial pressure is calculated by combining the return air relative humidity. The dew point temperature of the air is obtained by inverting the Anthony equation. The absolute humidity content is calculated based on the local atmospheric pressure and the actual water vapor partial pressure. A time series queue is established for the continuously sampled absolute humidity content data, and a first-order backward difference algorithm with low-pass filtering is executed to calculate the absolute humidity change rate.

3. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, Injecting a frequency command with a step pulse into the variable frequency compressor specifically includes: Trigger the detection cycle, temporarily suspend the outer loop frequency adjustment program of the variable frequency compressor and lock the current base operating frequency; A preset frequency step pulse amplitude is superimposed on the base operating frequency to continuously output a command frequency with a positive step pulse to the variable frequency compressor; The duration of the detection cycle is configured to be greater than the thermal time constant of the exhaust temperature sensor and less than the time required for the overall refrigeration cycle of the system to reach a new steady-state equilibrium.

4. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, The calculation steps for the implicit liquid buffer coefficient include: Within a preset effective data extraction window, the data sequence of the actual exhaust superheat is extracted, wherein the effective data extraction window is set by removing the dead time constant preset by the system. The transient rising slope is extracted by linearly fitting the data sequence using the least squares method. Based on the ratio of the difference between the baseline rising slope constant when there is no liquid refrigerant accumulation inside the gas-liquid separator under calibration conditions and the transient rising slope constant, the normalized implicit liquid phase buffer coefficient is calculated.

5. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, The calculation steps for the target evaporation temperature include: The baseline dew point offset is calculated by combining the deviation between the return air relative humidity and the target set relative humidity, as well as the absolute humidity change rate. The product of the implicit liquid phase buffer coefficient and the preset liquid phase buffer penalty coefficient is used as a constraint to dynamically reduce the basic dew point offset and obtain the optimized dew point offset. The target evaporation temperature is generated by subtracting the optimized dew point offset from the dew point temperature of the air.

6. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, The calculation steps for the actual latent potential ratio include: The return air temperature change rate is calculated using a first-order backward difference algorithm with low-pass filtering. The actual apparent-to-latent ratio is calculated based on the specific heat capacity of dry air at constant pressure, the latent heat of vaporization of water under the current conditions, the absolute value of the rate of change of the return air temperature, and the absolute value of the rate of change of the absolute humidity.

7. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 6, characterized in that, The steps for generating the target speed command include: The target apparent-to-latent ratio is calculated based on the deviation between the return air temperature and the target set temperature, and the deviation between the absolute moisture content and the target set absolute moisture content. The speed adjustment amount under the deviation between the actual potential ratio and the target potential ratio is calculated using a proportional-integral control algorithm, and the initial speed command is obtained by subtracting the speed adjustment amount from the current operating speed. The initial speed command is compared with the preset minimum speed constant for indoor fan anti-frost, and the maximum value of the two is taken as the target speed command.

8. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, The calculation steps for the comprehensive control deviation include: The difference between the value of 1 and the implicit liquid phase buffer coefficient is used as the inhalation side weight, which is multiplied by the deviation between the actual inhalation superheat and the target inhalation superheat. The implicit liquid phase buffer coefficient is multiplied by a preset matching coefficient constant as the exhaust side weight, and then multiplied by the deviation between the actual exhaust superheat and the target exhaust superheat. The product of the intake side weights and the product of the exhaust side weights are added together to obtain the overall control deviation. The matching coefficient constant is obtained from system calibration and is used to convert the dimensions of exhaust superheat deviation into the dimensions of intake superheat deviation.

9. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 1, characterized in that, The method further includes the step of performing liquid-sink protection: Real-time monitoring of the implicit liquid phase buffer coefficient and the actual exhaust superheat; When the implicit liquid phase buffer coefficient is determined to be greater than or equal to one, or the actual exhaust superheat is less than the preset exhaust superheat limit threshold, the anti-liquid hammer protection condition is met and the interruption intervention procedure is triggered.

10. The air-source heat pump dehumidification enhancement method for high-humidity environments according to claim 9, characterized in that, The execution logic of the interruption intervention procedure includes: The control of the actuator by the target evaporation temperature, the target speed command, and the comprehensive control deviation is interrupted. The opening of the electronic expansion valve is forcibly reduced to the minimum safe opening constant, the frequency of the variable frequency compressor is reduced to the anti-liquid slugging safe frequency constant, and the speed of the indoor fan is increased to the maximum speed constant. When the actual exhaust superheat rises to a level greater than the exhaust superheat recovery threshold and the duration exceeds the delay confirmation period, the interruption intervention procedure is exited and normal closed-loop control is restored.

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