Defrosting method and device of air conditioner, air conditioner control device, and storage medium

Abstract

The application relates to a defrosting method and device of an air conditioner, an air conditioner control device and a storage medium, wherein the method comprises the following steps: acquiring the surface temperature of an evaporator of the air conditioner in real time, determining the frost starting time according to the temperature change rate and the temperature change trend of the surface temperature; determining the target surface temperature of the evaporator before the frost starting time and the temperature difference between the target surface temperature and the surface temperature of the evaporator after the frost starting time reaches a phase change heat release peak value; acquiring the environmental humidity of the environment where the air conditioner is located, and adjusting a trigger threshold value for evaluating the frost amount according to the environmental humidity; determining the inertia duration of the air conditioner from starting operation to stable operation based on the operation parameters associated with the air conditioner; in the case that the temperature difference is greater than the trigger threshold value and the inertia duration is greater than a preset duration, determining the defrosting duration based on the inertia duration, and starting the defrosting mode based on the defrosting duration. Through the application, the defrosting efficiency of the air conditioner can be improved, and the air conditioner is more energy-saving.

Description

Technical Field

[0001] This application relates to the field of air conditioning defrosting technology, and in particular to a defrosting method and apparatus for an air conditioner, an air conditioner control device, and a storage medium. Background Technology

[0002] Existing evaporator defrosting technologies rely on fixed time or temperature thresholds for triggering, which are susceptible to environmental fluctuations, leading to a high false trigger rate. Specifically, existing frosting detection methods cannot effectively distinguish between the exothermic phase change of frosting (such as rapid temperature rise) and environmental interference (such as slow temperature changes), resulting in false frosting triggers. Summary of the Invention

[0003] This application provides a defrosting method and apparatus for an air conditioner, an air conditioner control device, and a storage medium to solve the problem that the defrosting mode activation has a high false trigger rate in the prior art due to relying on fixed time or temperature thresholds for defrosting.

[0004] In a first aspect, this application provides a defrosting method for an air conditioner, comprising: acquiring the surface temperature of the air conditioner evaporator in real time, and determining the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature; determining the temperature difference between the target surface temperature of the evaporator before the frosting start time and the temperature difference between the evaporator surface temperature after the frosting start time and the peak value of phase change heat release, wherein the larger the temperature difference, the thicker the frost layer accumulation; acquiring the ambient humidity of the environment where the air conditioner is located, and adjusting the trigger threshold for evaluating the amount of frost based on the ambient humidity; wherein the higher the ambient humidity, the lower the corresponding trigger threshold; determining the inertial time of the air conditioner from startup to stable operation based on the operating parameters associated with the air conditioner; and, when the temperature difference is greater than the trigger threshold and the inertial time is greater than a preset time, determining the defrosting time based on the inertial time, and activating the defrosting mode based on the defrosting time.

[0005] Optionally, determining the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature includes: determining whether the temperature change rate is greater than a first preset threshold and whether the temperature at the current moment is greater than the temperature at the previous moment; if the temperature change rate is greater than the first preset threshold and the temperature at the current moment is greater than the temperature at the previous moment, determining the current moment as the frosting start time.

[0006] Optionally, determining the temperature difference between the target surface temperature of the evaporator before the frosting initiation time and the evaporator surface temperature reaching the phase change heat release peak after the frosting initiation time includes: determining the average temperature value of the evaporator surface within a preset time period before the frosting initiation time, and determining the average temperature value as the target surface temperature; determining the peak value of the evaporator surface temperature during the rising phase after the frosting initiation time as the phase change heat release peak value; and determining the temperature difference between the target surface temperature and the phase change heat release peak value.

[0007] Optionally, adjusting the trigger threshold used to assess the amount of frost based on the ambient humidity includes: adjusting the trigger threshold based on the ambient humidity using the following formula: ΔT threshold =0.3°C - 0.1°C × (H - 60%) / 20; where, ΔT threshold H represents the trigger threshold, and H represents the ambient humidity.

[0008] Optionally, determining the inertial duration of the air conditioner from startup to stable operation based on operating parameters associated with the air conditioner includes: acquiring the following operating parameters in real time: the compressor current of the air conditioner, the refrigerant flow rate of the air conditioner, and the refrigerant pressure of the air conditioner; determining the compressor current fluctuation rate based on the compressor current, the refrigerant flow rate change rate based on the refrigerant flow rate, and the refrigerant pressure change rate based on the refrigerant pressure; determining the moment when the compressor current fluctuation rate is less than a second preset threshold, the refrigerant flow rate change rate is less than a third preset threshold, and the refrigerant pressure change rate is less than a fourth preset threshold as the moment when the air conditioner enters stable operation; and determining the duration of the air conditioner from startup to the specified moment as the inertial duration.

[0009] Optionally, determining the defrosting time based on the inertia duration includes: determining the defrosting time as the product of the inertia duration and a preset coefficient, wherein the preset coefficient is greater than 1.

[0010] Optionally, the method further includes: updating the preset coefficient by combining the historical inertia duration with the corresponding historical actual defrosting duration through linear regression.

[0011] Secondly, this application provides a defrosting device for an air conditioner, comprising: a first processing module, configured to acquire the surface temperature of the air conditioner evaporator in real time, and determine the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature; a second processing module, configured to determine the temperature difference between the target surface temperature of the evaporator before the frosting start time and the temperature difference between the evaporator surface temperature and the peak value of phase change heat release after the frosting start time, wherein the larger the temperature difference, the thicker the frost layer accumulation; a third processing module, configured to acquire the ambient humidity of the environment where the air conditioner is located, and adjust the trigger threshold for evaluating the amount of frost based on the ambient humidity; wherein the higher the ambient humidity, the lower the corresponding trigger threshold; a determining module, configured to determine the inertial duration of the air conditioner from startup to stable operation based on operating parameters associated with the air conditioner; and a defrosting module, configured to determine the defrosting duration based on the inertial duration when the temperature difference is greater than the trigger threshold and the inertial duration is greater than a preset duration, and to activate the defrosting mode based on the defrosting duration.

[0012] Thirdly, this application provides an air conditioner control device, comprising: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; and at least one memory connected to the at least one bus, wherein the processor is configured to execute the defrosting method of the air conditioner described in the first aspect of this application.

[0013] Fourthly, this application also provides a computer storage medium storing computer-executable instructions for executing the defrosting method of an air conditioner described in the first aspect of this application.

[0014] Compared with the prior art, the technical solution provided in this application has the following advantages: The method provided in this application acquires the surface temperature of the air conditioner evaporator in real time, determines the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature, then determines the temperature difference between the target surface temperature of the evaporator before the frosting start time and the evaporator surface temperature reaching the peak of phase change heat release after the frosting start time, and then acquires the ambient humidity of the environment where the air conditioner is located, adjusts the trigger threshold used to evaluate the amount of frost based on the ambient humidity, and determines the inertia time of the air conditioner from startup to stable operation based on the operating parameters associated with the air conditioner. Finally, when the temperature difference is greater than the trigger threshold and the inertia time is greater than the preset time, the defrosting time is determined based on the inertia time, and the defrosting mode is started based on the defrosting time. It can be seen that in this application embodiment, frosting detection is performed based on the evaporator surface temperature change rate and the peak of phase change heat release, and defrosting is performed after frosting by acquiring a dynamic threshold and after the system stabilizes, thereby improving the accuracy of frosting detection and the timeliness of defrosting. Attached Figure Description The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 A flowchart of a defrosting method for an air conditioner provided in this application embodiment; Figure 2 A flowchart of an intelligent defrosting method for an evaporator provided in this application embodiment; Figure 3 This is a schematic diagram of the structure of a defrosting device for an air conditioner provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of an air conditioner control device provided in an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0020] To address the problem of high false triggering rates of defrosting modes caused by relying on fixed time or temperature thresholds in existing technologies, this application provides a defrosting method for air conditioners, such as... Figure 1 As shown, it includes: Step 101: Obtain the surface temperature of the air conditioner evaporator in real time, and determine the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature. It should be noted that the surface temperature of an air conditioner's evaporator is not constant. When water vapor in the air condenses and freezes on the fins, it releases latent heat of phase change, causing a brief and rapid temperature rise. By continuously collecting temperature data (e.g., once per second), calculating the rate of temperature change (dT / dt), and observing whether the temperature shows an upward trend, the instant at which frost begins can be accurately captured. This method is more accurate than determining the frost initiation time based on slow temperature changes caused by environmental fluctuations.

[0021] In this specific example, the sampling interval Δt = 1 second. At t=10 seconds, Ts = -5.0°C; at t=11 seconds, Ts = -4.8°C. The calculation is dT / dt = (-4.8 - (-5.0)) / 1 = 0.2°C / s. If the first preset threshold is 0.05°C / s, and the current temperature -4.8°C > the previous temperature -5.0°C, then t=11 seconds is determined to be the frost initiation time. It is evident that this method can identify the frost initiation in a timely and accurate manner, avoiding misjudgments caused by environmental interference (such as changes in fan speed or refrigerant fluctuations), and providing a reliable time benchmark for subsequent frost quantity assessment.

[0022] Step 102: Determine the temperature difference between the target surface temperature of the evaporator before the frosting start time and the temperature difference between the evaporator surface temperature after the frosting start time and the peak value of phase change heat release. The larger the temperature difference, the thicker the frost layer. The target surface temperature refers to the average temperature (T) of the evaporator in a stable, frost-free state before frost formation begins. base This represents the baseline before frosting. The phase change heat release peak refers to the point at which the evaporator surface temperature rapidly rises to a maximum (T) after frosting begins due to the heat release from water vapor condensation. peak The temperature difference ΔT then decreases as the frost layer thickens and thermal resistance increases. Based on this, the temperature difference ΔT... peak = T peak -T base This difference directly reflects the heat released during phase change and is positively correlated with the thickness of the frost layer, ΔT. peak The larger the size, the thicker the frost.

[0023] In this specific example, the average temperature T within 10 seconds before frosting begins is... base = -6.0°C. The highest temperature T is reached 15 seconds after frosting begins.peak = -5.2°C. Temperature difference ΔT peak = (-5.2) - (-6.0) = 0.8°C, indicating that the frost layer is already quite thick. Therefore, quantitatively assessing the degree of frost accumulation by using the peak value of phase change heat release is more accurate than the timed or single-point temperature method used in existing technologies, avoiding misjudgments caused by fluctuations in ambient temperature.

[0024] Step 103: Obtain the ambient humidity of the environment where the air conditioner is located, and adjust the trigger threshold used to evaluate the amount of frost according to the ambient humidity; wherein, the higher the ambient humidity, the lower the corresponding trigger threshold. In high-humidity environments, the high water vapor content in the air leads to rapid frost formation. Using a fixed trigger threshold would result in delayed defrosting, excessively thick frost layers, and a sharp decrease in energy efficiency. Therefore, in this embodiment, the trigger threshold is dynamically adjusted based on humidity, enabling the system to defrost earlier, when the frost layer is still thin.

[0025] In a specific example, the baseline trigger threshold ΔT threshold =0.3°C (at 60% humidity). When humidity H = 80%, the adjusted ΔT threshold = 0.3 - 0.1×(80%-60%) / 20% = 0.3 - 0.1 = 0.2°C. If the temperature difference ΔT peak =0.25°C, then defrosting will be triggered at 80% humidity, but will not be triggered at 60% humidity. Therefore, in this embodiment, it can adapt to different climatic conditions, defrosting promptly in high humidity to prevent energy efficiency degradation, and avoiding ineffective defrosting in low humidity, thereby improving the annual energy efficiency ratio.

[0026] Step 104: Determine the inertial time of the air conditioner from startup to stable operation based on the operating parameters associated with the air conditioner; In this regard, inertial duration (T) inertia The operating time refers to the time required for an air conditioner to reach a stable operating state from startup (when the compressor starts running). Stable operation means that parameters such as compressor current, refrigerant flow rate, and refrigerant pressure fluctuate within acceptable ranges. Therefore, the operating parameters in this embodiment include compressor current, evaporator inlet refrigerant flow rate, and evaporator outlet refrigerant pressure. Inertia duration reflects the system's thermal inertia and the severity of initial operating conditions. For example, during low-temperature startup, the system requires a longer time to stabilize.

[0027] In the specific example, the air conditioner starts at time t0 = 0 seconds. At t = 30 seconds, the compressor current fluctuation rate σI = 5% (<8%), the refrigerant flow rate change rate |dQ / dt| = 1% (<2%), and the refrigerant pressure change rate |dP / dt| = 3% (<5%). If all these conditions are met, then t stable= 30 seconds, indicating that the air conditioner has entered a stable operating state. Therefore, the inertial duration T inertia = 30 - 0 = 30 seconds. It can be seen that the system stability is quantified in this embodiment to avoid forced defrosting before the system is stable (such as during startup or when the refrigerant distribution is uneven), thus preventing defrosting failure or impact on the compressor.

[0028] Step 105: When the temperature difference is greater than the trigger threshold and the inertia duration is greater than the preset duration, the defrosting duration is determined based on the inertia duration, and the defrosting mode is started based on the defrosting duration.

[0029] In this regard, a temperature difference greater than the trigger threshold indicates that the frost accumulation has reached a level requiring defrosting (frost amount condition). An inertia duration greater than the preset duration indicates that the system has entered a stable operating state (stability condition). The preset duration is typically 5 seconds to ensure it is not a transient state immediately following startup. Determining the defrosting duration based on the inertia duration means that the longer the inertia duration, the more stable the system, and the thicker or denser the frost layer, requiring a longer defrosting time. Therefore, in this embodiment, dual conditions ensure that defrosting is both timely and safe; the defrosting duration is linked to system inertia, avoiding insufficient or excessive defrosting due to a fixed duration, thus improving energy efficiency and reliability.

[0030] Furthermore, the defrosting mode in this application embodiment may include: an economical defrosting mode, i.e., when the frost layer thickness is moderate (e.g., the temperature difference is between 0.3°C and 0.6°C) and the ambient temperature T amb ≥ At 5°C, conventional reverse-cycle defrosting is used, with the defrosting time determined according to the aforementioned inertial time. The rapid defrosting mode is used when the frost layer is thick (temperature difference > 0.6°C) and the ambient temperature T... amb < At 5°C, a rapid defrosting mode with hot gas bypass and auxiliary electric heating is used, reducing the defrosting time to 70% of the conventional mode. This quickly removes thick frost and prevents the evaporator from freezing and being damaged. The pulse defrosting mode, used when the frost layer is thin (temperature difference ≤ 0.3°C) but the ambient humidity is high (H > 75%), employs intermittent pulse defrosting: defrosting runs for a third preset time (e.g., 30 seconds), stops for a fourth preset time (e.g., 60 seconds), and repeats multiple times (e.g., 3 times). This mode effectively removes thin frost while avoiding energy loss caused by over-defrosting. Therefore, in this embodiment, the most suitable defrosting mode can be dynamically matched according to the frost thickness and ambient temperature, maximizing system energy efficiency while ensuring defrosting effectiveness, especially significantly improving defrosting reliability and comfort in extreme low-temperature or high-humidity environments.

[0031] Through steps 101 to 105 above, the surface temperature of the air conditioner evaporator is acquired in real time. The frosting initiation time is determined based on the temperature change rate and trend of the surface temperature. Then, the target surface temperature of the evaporator before the frosting initiation time is determined, along with the temperature difference between the evaporator surface temperature reaching the peak phase change heat release value after the frosting initiation time. The ambient humidity of the air conditioner's environment is then acquired, and the trigger threshold for evaluating the amount of frost is adjusted based on the ambient humidity. Furthermore, the inertia time from startup to stable operation of the air conditioner is determined based on operating parameters associated with the air conditioner. Finally, if the temperature difference is greater than the trigger threshold and the inertia time is greater than a preset time, the defrosting time is determined based on the inertia time, and the defrosting mode is activated based on the defrosting time. Therefore, in this embodiment, frosting detection is performed based on the evaporator surface temperature change rate and the peak phase change heat release value. After frosting, a dynamic threshold is acquired, and defrosting is performed after the system stabilizes, thereby improving the accuracy of frosting detection and the timeliness of defrosting.

[0032] In this embodiment, after the defrosting mode is activated based on the defrosting duration, if the actual defrosting duration has reached the maximum allowable defrosting time (e.g., 15 minutes), the defrosting is forcibly terminated. If the actual defrosting duration has not reached the maximum allowable defrosting time, an adaptive defrosting termination step can be executed. Specifically, this step involves real-time monitoring of at least two parameters among the evaporator surface temperature, compressor current, evaporator outlet refrigerant pressure, and condenser outlet subcooling. Defrosting is terminated early when a preset termination condition is met. The termination condition includes at least one of the following: evaporator surface temperature greater than 0°C for more than 5 seconds; compressor current greater than or equal to 90% of the normal heating current; evaporator outlet pressure change rate less than 1% for more than 3 seconds; and condenser outlet subcooling greater than 5K.

[0033] As can be seen, in this embodiment of the application, by integrating multi-dimensional information such as temperature, current, pressure, and supercooling to determine the defrosting endpoint, the shortcomings of single temperature sensor response lag or local temperature measurement inaccuracy are overcome, which can more accurately end defrosting, reduce energy waste, and avoid secondary frost formation caused by incomplete defrosting.

[0034] In addition, during the defrosting process, multiple temperature sensors are placed at different locations on the evaporator surface to calculate the temperature difference between each region. If the difference between the maximum and minimum temperature difference values ​​in any region exceeds a fifth preset threshold, directional defrosting is initiated, concentrating the defrosting heat in the region with the larger temperature difference. For example, at least three temperature sensors are arranged along the refrigerant flow direction on the evaporator surface (located at the evaporator inlet, middle, and outlet sections, respectively). The system calculates the peak temperature difference of phase change heat release in each region. .in, Greater than ,and Greater than , if the maximum value and the minimum value have a difference greater than the fifth preset threshold (e.g., 0.2 °C), it is determined that the frost layer distribution is uneven. That is, the auxiliary heater corresponding to the thick frost area (e.g., a multi - segment PTC heating strip or a hot gas branch with independently adjustable flow rate) is controlled to operate at a higher power, while reducing the heating power in the thin frost area, or by adjusting the opening of the electronic expansion valve to change the refrigerant distribution, so that the defrosting heat is preferentially concentrated in the thick frost area, that is the corresponding area. By this method, the problem of local frosting caused by uneven air flow distribution or uneven refrigerant distribution can be solved, the defrosting uniformity and the overall heat exchange efficiency can be improved, and the residual frost layer after defrosting can be avoided.

[0035] In an optional implementation manner of the embodiment of the present application, for the method of determining the frosting start time according to the temperature change rate and temperature change trend determined based on the surface temperature involved in the above step 101, it can further include: Step 11, determining whether the temperature change rate is greater than the first preset threshold, and whether the temperature at the current moment is greater than the temperature at the previous moment; Step 12, when the temperature change rate is greater than the first preset threshold and the temperature at the current moment is greater than the temperature at the previous moment, determining the current moment as the frosting start time.

[0036] In this regard, the temperature change rate being greater than the first preset threshold indicates that the temperature rising rate is fast enough to exclude slow environmental fluctuations. Specifically, the first preset threshold can be optionally 0.05 °C / s, or can be set accordingly according to actual requirements. The temperature at the current moment being greater than the temperature at the previous moment indicates that the temperature drop situation is excluded, ensuring a real rising trend.

[0037] Specifically, taking the first preset threshold = 0.05 °C / s as an example, if the measured temperature change rate dT / dt = 0.08 °C / s (greater than 0.05), and Ts(t)= - 4.5 °C > Ts(t - 1)= - 4.7 °C, it is determined that frosting starts. If dT / dt = 0.08 °C / s, but Ts(t)<Ts(t - 1) (caused by noise, for example), there will be no misjudgment. Thus, in the embodiment of the present application, double verification can significantly reduce the false triggering rate, especially avoiding false frosting start signals caused by instantaneous noise of the sensor or electromagnetic interference.

[0038] In an optional implementation manner of the embodiment of the present application, for the method of determining the temperature difference value between the target surface temperature of the evaporator before the frosting start time and the surface temperature of the evaporator reaching the phase - change heat release peak after the frosting start time involved in the above step 102, it can further include: Step 21: Determine the average temperature value of the evaporator surface within a preset time period before the start of frosting, and set the average temperature value as the target surface temperature; Step 22: After the frosting start time, the peak value of the evaporator surface temperature during the rising phase is determined as the phase change heat release peak value. Step 23: Determine the temperature difference between the target surface temperature and the peak value of the phase change exothermic reaction.

[0039] To address this, a preset duration, such as 10 seconds before frosting begins, can be set according to actual needs. Using an average rather than a single point eliminates instantaneous fluctuations and obtains a stable reference temperature. The peak value during the rising phase refers to the temperature initially rising and then falling after frosting begins, typically reaching its peak within 15-20 seconds. Using this peak value best reflects the intensity of the phase change heat release.

[0040] In a specific example, the frost start time t start = 10:00:00, then calculate t start The average temperature in the first 10 seconds (09:59:50~10:00:00) is -6.2°C. From t start Monitoring began, and the temperature reached its highest point of -5.5°C at 10:00:18, which is T. peak The temperature difference is calculated as (-5.5) - (-6.2) = 0.7°C. Therefore, in this embodiment, because the reference temperature is more reliable and the peak value is captured completely, the temperature difference accurately reflects the frost layer thickness, avoiding errors caused by single-point temperature fluctuations or improper peak selection timing.

[0041] In an optional embodiment of this application, the method of adjusting the trigger threshold for evaluating the amount of frost based on ambient humidity in step 103 above can be further adjusted based on the ambient humidity using the following formula: Δ Tthreshold = 0.3°C - 0.1°C × (H - 60%) / 20, where Δ Tthreshold H represents the trigger threshold, and H represents the ambient humidity.

[0042] As can be seen, in this embodiment of the application, for high humidity environments with H > 60%, the trigger threshold can be adjusted using the above formula. When H ≤ 60%, Δ Tthreshold The threshold is fixed at 0.3°C. That is, when H>60%, the threshold decreases by 0.1°C for every 20% increase in humidity (from 60% to 80%).

[0043] In a specific example, such as H=70%, then Δ Tthreshold=0.3-0.1×(10% / 20%) = 0.3-0.05=0.25°C. If H=90%, then Δ Tthreshold =0.3-0.1(30% / 20%) =0.3-0.15= 0.15°C. It can be seen that this method is simple and effective, requiring no table lookup or complex calculations, and achieves humidity-adaptive defrosting triggering. Experiments have verified that in high humidity environments, defrosting can be initiated 15-30% earlier, improving energy efficiency by 5-10%.

[0044] In an optional embodiment of this application, the method of determining the inertial time of the air conditioner from startup to stable operation based on the operating parameters associated with the air conditioner in step 104 above may further include: Step 31: Obtain the following operating parameters in real time: air conditioner compressor current, air conditioner refrigerant flow rate, and air conditioner refrigerant pressure; Step 32: Determine the compressor current fluctuation rate based on the compressor current, the refrigerant flow rate change rate based on the refrigerant flow rate, and the refrigerant pressure change rate based on the refrigerant pressure. Step 33: The moment when the compressor current fluctuation rate is less than the second preset threshold, the refrigerant flow rate change rate is less than the third preset threshold, and the refrigerant pressure change rate is less than the fourth preset threshold is determined as the moment when the air conditioner enters stable operation. Step 34: Determine the duration of the air conditioner from startup to arrival as the inertial duration.

[0045] In this context, the compressor current fluctuation rate σI refers to the ratio of the standard deviation to the average value of the current over a calculated period, used to reflect load stability. The refrigerant flow rate change rate |dQ / dt| reflects the smoothness of the refrigerant flow at the evaporator inlet. The refrigerant pressure change rate |dP / dt| reflects the stability of the evaporator outlet pressure. The simultaneous satisfaction of these three conditions indicates that both the system's thermodynamics and mechanical motion have stabilized.

[0046] In the specific example, the air conditioner starts at t0 = 0 seconds. At t = 45 seconds: σI = 6% (<8%, second preset threshold), |dQ / dt| = 1.2% (<2%, third preset threshold), |dP / dt| = 3.5% (<5%, fourth preset threshold). It can be seen that the system is running stably, therefore the stable time t... stable = 45 seconds, that is, the inertial duration = 45 seconds.

[0047] As can be seen, in this embodiment of the application, the stability of the system's operating state is determined by multi-parameter fusion, which is more robust than a single temperature or pressure criterion. It can effectively eliminate unstable stages such as refrigerant two-phase oscillation and lubricating oil backflow in the initial stage of startup, and ensure that the system is in the best state when defrosting starts.

[0048] In an optional embodiment of this application, the method of determining the defrosting time based on inertia time involved in step 105 above may further include: Step 41: The product of the inertia duration and the preset coefficient is determined as the defrosting duration, where the preset coefficient is greater than 1.

[0049] Consequently, the longer the inertia duration, the more stable the system, and the thicker or denser the frost layer, requiring a longer defrosting time. Therefore, the preset coefficient is set to a value greater than 1, such as the inertia duration T. inertia = 40 seconds, preset coefficient a = 1.2, then the defrosting time is 1.2 * 40 = 48 seconds. It can be seen that in this embodiment, a physical relationship between defrosting time and system inertia is established, which is more scientific than the fixed time method and can adapt to the characteristics of different units, such as air conditioners of different sizes and with different refrigerants.

[0050] In an optional embodiment of this application, the preset coefficients can be updated using linear regression by combining historical inertia duration with the corresponding historical actual defrosting duration. Specifically, the historical actual defrosting duration refers to the actual time taken from the start of the last defrosting process until the evaporator surface temperature is greater than 0°C and remains so for a certain period of time (e.g., 10 seconds). Linear regression refers to fitting y=a·x + b with inertia duration as the independent variable and actual defrosting duration as the dependent variable. Typically, b=0 can be forced, and the slope a is updated. As the number of runs increases, a gradually approaches the optimal value of the current air conditioning system and operating environment.

[0051] In a specific example, such as storing the 5 most recent data: (T inertia Actual defrosting time) = [(20, 26), (25, 31), (30, 35), (35, 43), (40, 47)]. Based on this, linear regression (without intercept) yields a ≈ 1.18. Updating a from the initial 1.2 to 1.18, the next defrosting time = 1.18 × current T. inertia .

[0052] As can be seen, in this embodiment, the defrosting time is continuously optimized through self-learning capabilities, avoiding insufficient defrosting (residual frost layer) or excessive defrosting (energy waste). After long-term operation, it can not only improve system energy efficiency, but also adapt to changes such as unit aging and heat exchanger clogging.

[0053] The present application will be further explained below with reference to specific embodiments, which provide an intelligent defrosting method for evaporators, such as... Figure 2 As shown, the steps of this method include: Step 201: Start real-time monitoring of the evaporator temperature displayed on the air conditioner; Step 202, calculate the rate of temperature change dTs / dt = (Ts(t) - Ts(t-1)) / Δt; The system monitors the evaporator surface temperature Ts(t) in real time and calculates the rate of temperature change: dTs / dt = (Ts(t) - Ts(t-1)) / Δt (unit: °C / s). Ts(t) represents the evaporator surface temperature at the current time (time t). Ts(t-1) represents the evaporator surface temperature at the previous time (time t-1). Δt represents the time interval, which can be set to 1 second.

[0054] Step 203: Determine whether dTs / dt is greater than 0.05℃ and whether Ts(t) is greater than Ts(t-1). If yes, proceed to step 204; otherwise, proceed to step 202. When water vapor condenses and freezes on the evaporator fins, it releases latent heat of phase change, causing a brief rise in the evaporator surface temperature. When dTs / dt > the temperature change rate threshold (set to 0.05°C / s to distinguish between the rapid rise at the start of frosting and the slow change due to environmental disturbances) and T... s(t) >T s(t-1) When the temperature rise confirms the heat release during the phase transition and eliminates interference from the temperature drop, determine the start of frosting and record the start time t. start .

[0055] Step 204, record the frosting start time t. star Calculate the average temperature T 10 seconds before frosting. base Detect t star The highest temperature T within the last 20 seconds peak ; Step 205, calculate ΔT peak = T peak - T base ; Calculate the average temperature T 10 seconds before frosting. base Used as a baseline: Because the evaporator temperature is relatively stable before frosting begins, with no frosting interference, an average value (rather than a single point) is used to eliminate instantaneous fluctuations (such as small changes in ambient temperature). Temperature changes are small in the first 10 seconds before frosting, making averaging more reliable. The frosting process is detected from t... start At the start, the highest temperature T within 20 seconds peak Because during the frosting process, the temperature first rises (exothermic phase change) and then falls (the thickening of the frosting layer increases thermal resistance). peak It is the peak value of the rising phase, representing the intensity of phase change heat release. The actual measurement shows that it takes about 15-20 seconds for frost to form from the beginning to the peak value. 20 seconds can cover the main process of frost formation.

[0056] Calculate the instantaneous peak value of phase change heat release: ΔT peak = T peak - Tbase ;T base It is the stable temperature before frosting, T peak This is the highest temperature caused by the exothermic phase transition during frosting. ΔT peak The intensity of the phase change heat release is positively correlated with the thickness of the frosting.

[0057] Step 206, determine ΔT peak Is it greater than ΔT? threshold If yes, proceed to step 207; otherwise, proceed to step 202. When ΔT peak >Δ Tthreshold (Can be set to 0.3°C) indicates that frost has accumulated to the point where defrosting is necessary. Wherein, ΔT threshold This is the threshold value for the difference between the peak temperature and the reference temperature. It is dynamically adjusted based on humidity. Humidity H is acquired by an ambient humidity sensor placed at the air inlet. Specifically, ΔT threshold = 0.3°C - 0.1°C × (H - 60%) / 20. It can be seen that in this embodiment, the preset value of H > 60% is dynamically lowered because high humidity (H > 60%) results in a faster frosting rate (more water vapor), thus requiring earlier defrosting triggering. ΔT threshold Smaller.

[0058] Step 207: Check system stability, i.e., determine whether σI < 8% and |dQ / dt| < 2% and |dP / dt| < 5%; if yes, proceed to step 208; otherwise, proceed to step 206. When ΔT peak >ΔT threshold (The frost has accumulated to the point where it needs to be defrosted.) And T inertia( If the time required for the system to enter a stable operating state from startup is greater than 5 seconds (to avoid triggering defrost when the system is unstable and to ensure that the system has entered a stable operating state), the system will begin defrosting. When σI < 8% and |dQ / dt| < 2% and |dP / dt| < 5% are simultaneously true, the system records the current time t as the point in time when the system enters a stable operating state. stable Then T inertia = t stable - t start , where t start Indicates the system startup time; t stable T represents the moment when the system satisfies the stability condition. inertia This indicates the time required for the system to go from startup to a stable operating state.

[0059] σI represents the compressor current fluctuation rate. A current sensor at the compressor output is used to detect a current fluctuation rate <8%, indicating stable compressor operation. A current sensor at the compressor output is also used to detect the refrigerant flow rate change |dQ / dt|. A refrigerant flow rate change rate <2% indicates stable refrigerant flow. A pressure sensor at the evaporator outlet is used to detect the refrigerant pressure change rate |dP / dt|. If |dP / dt| <5%, it indicates stable refrigerant phase change, excluding transients.

[0060] Step 208: Begin defrosting and record the inertia duration T. inertia Calculate the defrosting time a × T inertia ; Based on T inertia Predict the time required for defrosting. After defrosting is triggered, based on T... inertia Dynamically set defrost duration: Defrost time = a × T inertia (seconds), because T inertia A larger value indicates a more stable system, meaning a thicker frost layer (requiring a longer defrosting time); T inertia A smaller value indicates greater system fluctuations, meaning a thinner frost layer (requiring a shorter defrosting time). Setting 'a' to 1.2 is because defrosting time is positively correlated with system stability, and defrosting requires heat transfer and phase change time, necessitating an additional 0.2 times the time to melt the frost layer.

[0061] In this embodiment, a self-learning mechanism for historical defrosting data can also be introduced—the system stores the T data from the last 5 defrosts. inertia The actual defrosting time (the time from the start of defrosting to 10 seconds when the evaporator surface temperature is >0°C) was compared with y using a simple linear regression (y = a×T). inertia + b) Fine-tune the coefficient a (initially a=1.2, updated based on historical data) to make the defrosting time more closely match actual needs (avoiding insufficient or excessive defrosting). Defrosting ends when the required defrosting time is reached.

[0062] Step 209: Once the defrosting time is reached, exit the defrosting process.

[0063] Through steps 201 to 209 above, frost detection is performed based on the evaporator surface temperature change rate and the peak value of phase change heat release. Furthermore, the defrost trigger threshold is dynamically adjusted based on ambient humidity, enabling the system to adapt to frost rates under different humidity conditions. Additionally, based on the system's steady-state (T... inertia The system uses a dynamic defrosting time calculation mechanism and learns from historical data to optimize the defrosting time and avoid insufficient or excessive defrosting.

[0064] Corresponding to the above Figure 1 This application also provides a defrosting device for an air conditioner, such as... Figure 3 As shown, the device includes: The first processing module 302 is used to acquire the surface temperature of the air conditioner evaporator in real time, and determine the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature. The second processing module 304 is used to determine the temperature difference between the target surface temperature of the evaporator before the frosting start time and the temperature difference between the evaporator surface temperature after the frosting start time when the phase change heat release peak is reached. The larger the temperature difference, the thicker the frost layer accumulation. The third processing module 306 is used to obtain the ambient humidity of the environment where the air conditioner is located, and adjust the trigger threshold for evaluating the amount of frost according to the ambient humidity; wherein, the higher the ambient humidity, the lower the corresponding trigger threshold. The determination module 308 is used to determine the inertial duration of the air conditioner from startup to stable operation based on the operating parameters associated with the air conditioner; The defrosting module 310 is used to determine the defrosting duration based on the inertia duration when the temperature difference is greater than the trigger threshold and the inertia duration is greater than the preset duration, and to start the defrosting mode based on the defrosting duration.

[0065] The apparatus of this application embodiment acquires the surface temperature of the air conditioner evaporator in real time, determines the frosting initiation time based on the temperature change rate and trend determined by the surface temperature, then determines the temperature difference between the target surface temperature of the evaporator before the frosting initiation time and the evaporator surface temperature reaching the peak of phase change heat release after the frosting initiation time, and further acquires the ambient humidity of the environment where the air conditioner is located. Based on the ambient humidity, the trigger threshold used to evaluate the amount of frost is adjusted, and the inertia time from start-up to stable operation of the air conditioner is determined based on the operating parameters associated with the air conditioner. Finally, if the temperature difference is greater than the trigger threshold and the inertia time is greater than a preset time, the defrosting time is determined based on the inertia time, and the defrosting mode is initiated based on the defrosting time. Therefore, in this application embodiment, frosting detection is performed based on the evaporator surface temperature change rate and the peak of phase change heat release, and defrosting is performed after frosting by acquiring a dynamic threshold and after the system stabilizes, thereby improving the accuracy of frosting detection and the timeliness of defrosting.

[0066] In an optional embodiment of this application, the first processing module in this application includes: a first determining unit, used to determine whether the temperature change rate is greater than a first preset threshold and whether the temperature at the current moment is greater than the temperature at the previous moment; and a second determining unit, used to determine the current moment as the frosting start time when the temperature change rate is greater than the first preset threshold and the temperature at the current moment is greater than the temperature at the previous moment.

[0067] In an optional embodiment of this application, the second processing module in this application includes: a third determining unit, used to determine the average temperature value of the evaporator surface within a preset time before the frosting start time, and to determine the average temperature value as the target surface temperature; a fourth determining unit, used to determine the peak value of the evaporator surface temperature during the rising phase after the frosting start time as the phase change heat release peak value; and a fifth determining unit, used to determine the temperature difference between the target surface temperature and the phase change heat release peak value.

[0068] In an optional embodiment of this application, the third processing module includes: a first processing unit, configured to adjust the trigger threshold based on ambient humidity using the following formula: Δ Tthreshold = 0.3°C - 0.1°C × (H - 60%) / 20, where Δ Tthreshold H represents the trigger threshold, and H represents the ambient humidity.

[0069] In an optional embodiment of this application, the determining module includes: an acquisition unit, configured to acquire the following operating parameters in real time: the compressor current of the air conditioner, the refrigerant flow rate of the air conditioner, and the refrigerant pressure of the air conditioner; a second processing unit, configured to determine the compressor current fluctuation rate based on the compressor current, the refrigerant flow rate change rate based on the refrigerant flow rate, and the refrigerant pressure change rate based on the refrigerant pressure; a third processing unit, configured to determine the moment when the compressor current fluctuation rate is less than a second preset threshold, the refrigerant flow rate change rate is less than a third preset threshold, and the refrigerant pressure change rate is less than a fourth preset threshold as the moment when the air conditioner enters stable operation; and a sixth determining unit, configured to determine the duration of the air conditioner from startup to arrival as the inertial duration.

[0070] In an optional embodiment of this application, the defrosting module in this application includes: a seventh determining unit, used to determine the product of the inertial duration and a preset coefficient as the defrosting duration, wherein the preset coefficient is greater than 1.

[0071] In an optional embodiment of this application, the apparatus further includes an update module, used to update a preset coefficient by combining the historical inertial duration with the corresponding historical actual defrosting duration through linear regression.

[0072] like Figure 4 As shown in the figure, this application provides an air conditioner control device, including a processor 411, a communication interface 412, a memory 413, and a communication bus 414, wherein the processor 411, the communication interface 412, and the memory 413 communicate with each other through the communication bus 414. Memory 413 is used to store computer programs; In one embodiment of this application, when the processor 411 executes the program stored in the memory 413, it implements the defrosting method of the air conditioner provided in any of the aforementioned method embodiments, and its function is similar, so it will not be described again here.

[0073] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the defrosting method for an air conditioner as provided in any of the foregoing method embodiments.

[0074] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0075] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0076] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0077] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A defrosting method for an air conditioner, characterized in that, include: The surface temperature of the air conditioner evaporator is acquired in real time, and the frosting start time is determined based on the temperature change rate and temperature change trend determined by the surface temperature. The target surface temperature of the evaporator before the frosting start time is determined, and the temperature difference between the evaporator surface temperature reaching the peak of phase change heat release after the frosting start time is determined, wherein the larger the temperature difference value, the thicker the frost layer accumulation. The ambient humidity of the environment where the air conditioner is located is obtained, and the trigger threshold for evaluating the amount of frost is adjusted according to the ambient humidity; wherein, the higher the ambient humidity, the lower the corresponding trigger threshold. The inertial time of the air conditioner from startup to stable operation is determined based on the operating parameters associated with the air conditioner; When the temperature difference is greater than the trigger threshold and the inertia duration is greater than the preset duration, the defrosting duration is determined based on the inertia duration, and the defrosting mode is activated based on the defrosting duration.

2. The method according to claim 1, characterized in that, Determining the frosting initiation time based on the temperature change rate and temperature change trend determined by the surface temperature includes: Determine whether the rate of temperature change is greater than a first preset threshold, and whether the temperature at the current moment is greater than the temperature at the previous moment; If the rate of temperature change is greater than the first preset threshold and the temperature at the current moment is greater than the temperature at the previous moment, then the current moment is determined to be the frost start time.

3. The method according to claim 1, characterized in that, The temperature difference between the target surface temperature of the evaporator before the frosting initiation time and the evaporator surface temperature after the frosting initiation time reaching the peak value of phase change exothermic reaction includes: Determine the average temperature value of the evaporator surface within a preset time period before the start time of frosting, and determine the average temperature value as the target surface temperature; After the frosting initiation time, the peak value of the evaporator surface temperature during the rising phase is determined as the phase change exothermic peak value. Determine the temperature difference between the target surface temperature and the peak value of the phase change exothermic reaction.

4. The method according to claim 1, characterized in that, Adjusting the trigger threshold used to assess frost amount based on the ambient humidity includes: The trigger threshold is adjusted based on ambient humidity using the following formula: ΔT threshold = 0.3°C-0.1°C×(H-60%) / 20 Where, ΔT threshold H represents the trigger threshold, and H represents the ambient humidity.

5. The method according to claim 1, characterized in that, The inertial time of the air conditioner from startup to stable operation is determined based on the operating parameters associated with the air conditioner, including: The following operating parameters are acquired in real time: compressor current of the air conditioner, refrigerant flow rate of the air conditioner, and refrigerant pressure of the air conditioner; The compressor current fluctuation rate is determined based on the compressor current, the refrigerant flow rate change rate is determined based on the refrigerant flow rate, and the refrigerant pressure change rate is determined based on the refrigerant pressure. The moment when the compressor current fluctuation rate is less than the second preset threshold, the refrigerant flow rate change rate is less than the third preset threshold, and the refrigerant pressure change rate is less than the fourth preset threshold is determined as the moment when the air conditioner enters stable operation. The duration from the start-up of the air conditioner to the specified time is defined as the inertial duration.

6. The method according to claim 1, characterized in that, Determining the defrosting time based on the inertial duration includes: The product of the inertial duration and the preset coefficient is determined as the defrosting duration, wherein the preset coefficient is greater than 1.

7. The method according to claim 6, characterized in that, The method further includes: The preset coefficients are updated by combining historical inertia duration with corresponding historical actual defrosting duration through linear regression.

8. A defrosting device for an air conditioner, characterized in that, include: The first processing module is used to acquire the surface temperature of the air conditioner evaporator in real time, and determine the frosting start time based on the temperature change rate and temperature change trend determined by the surface temperature. The second processing module is used to determine the temperature difference between the target surface temperature of the evaporator before the frosting start time and the surface temperature of the evaporator after the frosting start time reaches the peak value of phase change heat release, wherein the larger the temperature difference value, the thicker the frost layer accumulation. The third processing module is used to obtain the ambient humidity of the environment where the air conditioner is located, and adjust the trigger threshold for evaluating the amount of frost according to the ambient humidity; wherein, the higher the ambient humidity, the lower the corresponding trigger threshold. The determination module is used to determine the inertial duration of the air conditioner from startup to stable operation based on the operating parameters associated with the air conditioner; The defrosting module is used to determine the defrosting duration based on the inertia duration when the temperature difference value is greater than the trigger threshold and the inertia duration is greater than the preset duration, and to start the defrosting mode based on the defrosting duration.

9. An air conditioner control device, characterized in that, include: The processor, communication interface, memory, and communication bus are connected, with the processor, communication interface, and memory communicating with each other via the communication bus. The memory is used to store a computer program; the processor is used to execute the computer program to implement the defrosting method of the air conditioner according to any one of claims 1-7.

10. A storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the defrosting method of the air conditioner according to any one of claims 1-7.

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