A collaborative frost prevention and non-stop defrosting intelligent control system for an air source heat pump

Abstract

The application provides a kind of for air source heat pump's coordinated frost prevention and defrosting without stopping intelligent control system, including frost trend identification module, dynamic defrosting determination module, heat distribution control module and defrosting execution and exit module.System obtains trend deviation by collecting evaporation side and ambient temperature and humidity, calculating evaporation temperature difference and carrying out sliding window weighted trend estimation;Based on the deviation dynamic adjustment defrosting threshold, accurately generate defrosting state flag;After defrosting starts, determine the proportion of branch heat distribution according to dynamic threshold, generate main and branch electronic expansion valve target opening;And through the limited rate adjustment valve, complete branch defrosting while ensuring continuous main road heating, and smoothly exit defrosting when meeting stable conditions.System uses mutually independent main road and branch refrigerant channel, realizes efficient, no sense, no defrosting, significantly improves the operation stability and energy efficiency of heat pump in low temperature and high humidity environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of heat pumps, and particularly relates to a collaborative frost prevention and non-stop defrosting intelligent control system for an air source heat pump. BACKGROUND

[0002] As a heating equipment taking air as low-grade heat source, air source heat pump is widely used in building heating and domestic hot water fields, and its energy saving and environmental friendly characteristics make it an important technical path to replace traditional fossil energy heating. However, under typical winter conditions such as low temperature and high humidity, frost layer is easily formed on the surface of the outdoor heat exchanger of the air source heat pump. The gradual accumulation of the frost layer will significantly weaken the heat exchange capacity, resulting in the decrease of the evaporation temperature, the increase of the compressor load and the deterioration of the overall energy efficiency. The existing air source heat pump systems generally use timed defrosting or defrosting control method based on single temperature difference and pressure threshold. Such methods can only trigger defrosting when the frost layer has been formed and has a significant impact on system operation, and there are problems of response lag and rough judgment. In actual operation, it is easy to cause serious heat exchange obstruction due to late defrosting, or frequent triggering of defrosting under environmental disturbance conditions, resulting in heating interruption, water temperature fluctuation and energy consumption increase. Some technical solutions try to alleviate the influence of frosting by increasing the evaporation temperature or introducing auxiliary heating devices, but often at the cost of sacrificing heating capacity or increasing system complexity and operating cost, and it is difficult to achieve stable results under different conditions. With the expansion of air source heat pump application scenarios to cold, humid and long-time continuous operation, how to realize early identification of the frosting evolution process without significantly increasing the hardware complexity of the system, and maintain the continuity of heating during the defrosting process, has become a key technical problem restricting the performance improvement and user experience improvement of air source heat pump. SUMMARY

[0003] The purpose of the present application is to design a collaborative frost prevention and non-stop defrosting intelligent control system for an air source heat pump, which can reduce unnecessary defrosting times without relying on additional heating devices, reduce the impact of the defrosting process on the heating capacity, improve the running stability and energy efficiency of the system under complex environmental conditions, and effectively improve the user-side heating continuity and comfort.

[0004] In order to achieve the above purpose, the present application provides a collaborative frost prevention and non-stop defrosting intelligent control system for an air source heat pump, which comprises:

[0005] A frost trend identification module is used to periodically collect the evaporation side temperature, the environment temperature and the relative humidity of the environment, calculate the current evaporation temperature difference, and perform weighted trend estimation on the evaporation temperature difference based on a sliding time window to obtain a temperature difference trend estimation value, and then calculate a trend deviation amount.

[0006] A dynamic defrosting determination module, which is in communication connection with the frost tendency identification module, is configured to dynamically adjust a defrosting determination threshold based on the trend deviation amount, and generate a defrosting state flag in combination with the evaporative temperature difference and the dynamically adjusted defrosting determination threshold;

[0007] A heat distribution control module, which is in communication connection with the dynamic defrosting determination module, is configured to determine a branch heat distribution ratio according to the dynamically adjusted defrosting determination threshold when the defrosting state flag is valid, and generate a main circuit electronic expansion valve target opening degree and a branch electronic expansion valve target opening degree;

[0008] A defrosting execution and exit module, which is in communication connection with the heat distribution control module, is configured to gradually adjust the branch electronic expansion valve opening degree to the branch electronic expansion valve target opening degree at a defined change rate after the electromagnetic valve is turned on, while maintaining the main circuit electronic expansion valve opening degree in a range not lower than the main circuit minimum opening degree; and generate a defrosting exit flag when the branch heat distribution ratio is equal to a minimum defrosting distribution ratio and the fin heat exchange state remains stable within a continuous control period, and gradually close the branch electronic expansion valve and the electromagnetic valve at a defined change rate;

[0009] The system is provided with a main circuit refrigerant channel and a branch refrigerant channel which are independent of each other, the main circuit refrigerant channel is provided with a main circuit electronic expansion valve, the branch refrigerant channel is provided with a branch electronic expansion valve and an electromagnetic valve, and the electromagnetic valve is used to control the on-off of the branch refrigerant channel.

[0010] Further, the evaporative side temperature relied on by the frost tendency identification module is obtained by a temperature sensor at the outlet of the main circuit refrigerant channel, and the environmental temperature and the environmental relative humidity are obtained by a sensor at the air inlet side of the composite fin heat exchanger.

[0011] Further, when the frost tendency identification module performs sliding time window weighted trend estimation on the evaporative temperature difference, the sliding time window covers continuous sampling periods, and the weight coefficient of each historical sampling point in the window monotonically decreases with the increase of the time interval between its sampling time and the current sampling time.

[0012] Further, when the dynamic defrosting determination module adjusts the defrosting determination threshold, the defrosting determination threshold of the last period, the base threshold, the trend deviation amount and the threshold inertia coefficient are fused to make the threshold change smoothly with the frost tendency.

[0013] Further, when the dynamic defrosting determination module generates the defrosting state flag, a one-sided weighting term is introduced only when the trend deviation amount is negative to tighten the triggering condition, and the condition must be established within a continuous sampling period before it is set to valid.

[0014] Further, the heat distribution control module obtains the branch heat distribution ratio by linearly mapping a normalized difference between the dynamically adjusted defrosting determination threshold and the base threshold to between a preset minimum distribution ratio and a maximum distribution ratio.

[0015] Further, when the heat distribution control module calculates the main circuit electronic expansion valve target opening degree, the main circuit reference opening degree locked before defrosting starts, the branch electronic expansion valve target opening degree increment, and the main-branch linkage coefficient are used to limit the opening degree to be no less than the main circuit minimum opening degree.

[0016] Further, the defrosting execution and exit module limits the adjustment range of the branch electronic expansion valve opening degree and the main circuit electronic expansion valve opening degree to be no more than a preset maximum change step in each control cycle.

[0017] Further, when the defrosting execution and exit module generates the defrosting exit flag, the following conditions need to be met simultaneously: the branch heat distribution ratio is equal to the minimum defrosting distribution ratio, and the fin surface temperature and the system pressure remain stable and have no continuous upward trend in the continuous control cycle.

[0018] Further, after the defrosting execution and exit module controls the solenoid valve to be turned on, the branch electronic expansion valve opening degree is adjusted after a delay of a stable window to suppress the instantaneous impact of the refrigerant flow.

[0019] The beneficial technical effects of the present application are at least the following points:

[0020] To solve the above problems, the present application provides a collaborative frost prevention and non-stop defrosting intelligent control system for an air source heat pump, which realizes early identification of frost risk, dynamic determination of defrosting opportunity, and energy collaborative adjustment in the defrosting process through continuous sensing and phased control of the system operating state. The control system judges the frost evolution trend of the heat exchanger based on the internal relationship between the evaporation side operating state and the environmental conditions, and generates defrosting determination conditions that change with the working conditions, so that the defrosting behavior can better fit the actual operating state. After entering the defrosting stage, the main-branch heat distribution of the composite fin heat exchanger is finely controlled, so that the system can maintain continuous heating of the main circuit while the branch obtains heat supply to meet the defrosting demand, thereby realizing defrosting process control under non-stop conditions. The present application combines defrosting determination, heat distribution, and execution control organically to build a complete collaborative control logic, which can reduce unnecessary defrosting times without relying on additional heating devices, reduce the impact of the defrosting process on the heating capacity, improve the operating stability and energy efficiency of the system under complex environmental conditions, and effectively improve the user-side heating continuity and comfort. BRIEF DESCRIPTION OF DRAWINGS

[0021] The application is further illustrated by the accompanying drawings, but the embodiments in the drawings do not constitute any limitation to the application, and other embodiments can be obtained by those skilled in the art without creative effort on the basis of the following drawings.

[0022] Figure 1 A schematic diagram of an intelligent control system for coordinated frost prevention and non-stop defrosting of an air source heat pump. DETAILED DESCRIPTION

[0023] Embodiments of the application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the application only, and cannot be understood as a limitation to the application.

[0024] In one or more embodiments, as shown in Figure 1 An intelligent control system for coordinated frost prevention and non-stop defrosting of an air source heat pump is disclosed, the system comprising:

[0025] A frost trend identification module for periodically collecting the evaporation side temperature, the ambient temperature and the ambient relative humidity, calculating the current evaporation temperature difference, and performing a weighted trend estimation on the evaporation temperature difference based on a sliding time window to obtain a temperature difference trend estimation value, and then calculating a trend deviation amount;

[0026] A dynamic defrosting determination module communicatively connected to the frost trend identification module for dynamically adjusting a defrosting determination threshold based on the trend deviation amount, and generating a defrosting state flag in combination with the evaporation temperature difference and the dynamically adjusted defrosting determination threshold;

[0027] A heat distribution control module communicatively connected to the dynamic defrosting determination module for determining a branch heat distribution ratio according to the dynamically adjusted defrosting determination threshold when the defrosting state flag is valid, and generating a main circuit electronic expansion valve target opening degree and a branch electronic expansion valve target opening degree;

[0028] A defrosting execution and exit module communicatively connected to the heat distribution control module for gradually adjusting the branch electronic expansion valve opening degree to the branch electronic expansion valve target opening degree at a defined change rate after the solenoid valve is turned on while maintaining the main circuit electronic expansion valve opening degree in a range not lower than the main circuit minimum opening degree, and generating a defrosting exit flag when the branch heat distribution ratio is equal to the minimum defrosting distribution ratio and the fin heat exchange state remains stable within a continuous control period, and gradually closing the branch electronic expansion valve and the solenoid valve at a defined change rate;

[0029] The system is provided with a main refrigerant channel and branch refrigerant channels that are independent of each other. The main refrigerant channel is equipped with a main electronic expansion valve, and the branch refrigerant channels are equipped with branch electronic expansion valves and solenoid valves. The solenoid valves are used to control the opening and closing of the branch refrigerant channels.

[0030] Specifically, the intelligent control system for coordinated anti-frost and non-stop defrosting of the air source heat pump provided in this embodiment of the invention operates as follows:

[0031] S1: This step is used to identify whether the heat exchanger is evolving towards a frosting state during normal heating operation of the air source heat pump. Its core purpose is to determine "whether it is approaching the frosting condition". This is because in actual operation, the formation of frost has obvious time accumulation characteristics. If the judgment is based solely on the temperature difference threshold at a certain moment, it is easy to cause false triggering when there is environmental disturbance or load fluctuation, which will lead to unnecessary defrosting actions.

[0032] In practical implementation, the air source heat pump controller periodically collects key physical quantities on the evaporator side. The evaporation temperature is collected by a temperature sensor located at the main outlet of the composite finned heat exchanger. This sensor is typically a surface-mounted thermistor or platinum resistance thermometer, with its measuring point close to the refrigerant pipe wall, reflecting the actual temperature state after refrigerant evaporation. Ambient temperature and relative humidity are collected by an integrated temperature and humidity sensor installed on the air inlet side of the heat exchanger. This location provides a better reflection of the true state of the air entering the finned area, avoiding deviations caused by return air inside the casing. Within each sampling cycle, the controller first calculates the corresponding dew point temperature based on the ambient temperature and relative humidity, and then further obtains the evaporation temperature difference at the current moment. This temperature difference reflects the thermal margin between the evaporator surface and the air dew point. Instead of immediately using the single-point data, the system uses temperature differences over a recent period to form a sliding time window. Taking a common configuration in practical engineering as an example, if the sampling period is 10 seconds, the most recent 12 sampling points can be selected, covering approximately 2 minutes of operation, to reflect the continuous variation characteristics of the temperature difference.

[0033] Based on this, the controller uses a weighted summation method to estimate the trend of the temperature difference sequence within the time window, and its calculation form is as follows:

[0034] ;

[0035] in, This represents the number of sampling points within the sliding time window, as shown in the example configuration. ; Relative to the current time Historical sampling sequence number, Corresponding to the most recent historical sampling, The earliest historical sample within the corresponding window; Indicates the first The weighting coefficients of each historical sampling point are preset according to the principle of "the closer to the current time, the greater the weight" (for example, the two most recent sampling points each account for a higher proportion, and the earliest points account for a lower proportion). Indicates at time Evaporation temperature difference sample; This represents the time obtained by the above weighted summation. The estimated value of the temperature difference trend is given. This weight distribution method has two advantages in practical applications: on the one hand, it can preserve the overall trend of temperature difference changes, and on the other hand, it can suppress occasional jumps caused by instantaneous wind speed changes or load fluctuations.

[0036] After obtaining the trend estimate, the system compares it with the actual temperature difference at the current moment and defines the trend deviation. :

[0037] ;

[0038] in, This represents the actual evaporation temperature difference at the current moment; This represents the estimated temperature difference trend obtained based on the sliding window sequence; This indicates the degree of deviation of the current temperature difference from the trend value. When the value is close to zero, it indicates that the system's operating state is consistent with recent trends; when... When the value is negative and the magnitude gradually increases, it means that the current evaporation temperature difference is falling below its historical evolution trend. This typically corresponds to the early stage where the heat exchanger surface is gradually covered by frost, leading to a decrease in heat exchange capacity. For example, under operating conditions of an outdoor air temperature of 2°C and a relative humidity of 85%, during the initial operation of the system... It may stabilize at a certain level. After running for several minutes, if the air humidity does not change significantly, but frost gradually appears on the fin surface, the evaporation temperature will slowly decrease. It will start to fall below the average level of the previous period, leading to The values ​​are continuously negative. This change often precedes the traditional "temperature difference below a fixed threshold" criterion, thus providing a time window for subsequent control strategies. This step ultimately outputs two quantities: one is the evaporation temperature difference at the current moment. Secondly, it reflects the degree of deviation from the trend. .

[0039] S2: This step is the output of step S1. and Based on this, the "dynamic determination of defrosting status and threshold adjustment" were completed. Among them, Provide the instantaneous thermal margin between the evaporation side and the dew point. The deviation of this margin from the short-term trend is given. In engineering, It is more sensitive to environmental disturbances (fluctuations in wind speed, compressor frequency fine-tuning, air inlet backflow), and It can better reflect the early characteristics of "frost layer gradually forming leading to slow decline in heat exchange capacity". Therefore, this step combines the two into a decision chain that can be directly applied to the controller: first generate a "dynamic threshold that changes with operating conditions and does not fluctuate" , and then give the defrosting state flag according to it, so as to provide a unique and explicit trigger signal for the next step of main branch defrosting.

[0040] The generation of the dynamic threshold adopts the form of "trend deviation driving + threshold inertia constraint". The controller internally saves the threshold of the last control period (this quantity is a controller memory variable and does not require additional sensors), and fuses it with the target threshold derived by the current trend, so that the threshold adjusts with the frosting trend while avoiding threshold jumps caused by instantaneous disturbances. Its calculation form is:

[0041] ;

[0042] where, represents the dynamic threshold for defrosting determination in the current period, which is saved as a real-time calculation result in the controller; represents the dynamic threshold that has taken effect in the last period, which is read from the controller storage; represents the basic threshold parameter, which is written into the controller parameter table during unit commissioning or calibration; represents the trend deviation adjustment coefficient of the threshold, which is also determined and fixed during the commissioning phase; from step S1 output; represents the threshold inertia coefficient, which is used to limit the threshold change speed and is usually selected as a fixed value according to the unit control period and the heat inertia of the heat exchanger. The engineering meaning of this expression is: when the consecutive negative and the amplitude increase, the item in the brackets will push up (or tighten) the threshold, so that the system enters the defrosting determination area earlier; when it returns to near zero or turns positive, the threshold will smoothly return to the basic level, thereby reducing the back-and-forth switching of defrosting determination near the boundary.

[0043] After obtaining , this step designs the defrosting determination as a combination of "threshold comparison + single-sided weighting term of trend deviation", so as to be more sensitive in the frost layer development stage and more restrained in the short-term disturbance stage dominated by non-frost layer. The controller directly generates the defrosting state flag :

[0044] ;

[0045] where, is the output from step S1, representing the current evaporating temperature difference; is the dynamic threshold calculated for this step; is the output from step S1; is the one-sided term of the trend deviation, only in effect when is negative (i.e. the current temperature difference is lower than the trend estimate, showing a “deviation towards frosting”); is the one-sided weighting coefficient, fixed in the commissioning phase, used to control the additional push of the trend deviation on the triggering condition; is the defrost status flag, as the controller output state quantity for the next step to read. The decision can be directly implemented in the controller as a comparison instruction and a simple arithmetic operation: first calculate , then calculate the right side of the triggering limit, and finally get by a comparison. If further suppression of transient false positives is required in engineering, the above inequality can be required to hold for a number of consecutive sampling periods before is set to TRUE. This continuity constraint can be implemented using a counter without introducing new calculation variables.

[0046] Combining the actual operating characteristics of air source heat pumps, a typical scenario can be used to understand the action mode of this mechanism: when the humidity rises at night and the fins gradually frost, often show a slow downward trend, and the output from step S1 will continue to be negative and gradually expand during the downward process. At this time, the first formula will make smoothly adjust to a more sensitive direction, and the one-sided weighting term in the second formula will further “tighten” the triggering limit, so that can be stably set to TRUE before the frost layer has not significantly thickened and the heat exchanger has not been seriously blocked. When only the fan speed changes or the compressor frequency is adjusted slightly, more likely to be close to zero or quickly return, the one-sided term weakens, and the threshold does not jump because of the inertia constraint of , so that remains stable. In this way, the output of this step has both sensitivity to the evolution of the frost layer and robustness to short-term disturbances, and can form a clear, single, and directly callable defrost state entry at the controller level.

[0047] The output of this step is limited to two quantities: the dynamic threshold and the defrost status flag . Among them as a decision reference that can be recorded internally by the controller, it is convenient for subsequent control processes to maintain consistency; As the next step main branch heat distribution and trigger condition of the execution control, directly determine whether the solenoid valve, branch electronic expansion valve and fan and other components into the non-stop defrosting collaborative work state.

[0048] S3: This step is used to output the heat distribution ratio of the defrosting process under the premise of step S2 With The ratio is converted into a set of executable control parameters for the main and branch circuits. In engineering, the main circuit of the composite fin heat exchanger bears the task of continuous heating, and the branch circuit bears the task of "heat supplement" to the frost area. This step further refines the discrete result of "entering defrosting state" into "how much heat the branch should take, how much the valve should be opened, and how fast it should be in place", so as to ensure controllable defrosting action, uninterrupted main circuit heating, and avoid excessive branch heat causing high pressure rapid rise or main circuit heating capacity being lowered.

[0049] Determine whether this step enters the heat distribution calculation: when is FALSE, this step does not generate new defrosting distribution parameters, but keeps the branch target opening at the closed or minimum bypass state; when is TRUE, this step enters the effective calculation process. The "urgency" of the defrosting trigger threshold under the current working condition, which has integrated the trend deviation and threshold inertia in step S2, can be directly used as the input of the distribution strength without introducing additional temperature difference measurement variables in this step.

[0050] In specific implementation, the controller first calculates the branch heat distribution ratio The meaning of this ratio is: during defrosting, the system allocates a relative intensity to the branch defrosting circuit under the premise of ensuring continuous heating of the main circuit. The calculation of uses the form of "threshold urgency normalization and linear mapping": when is closer to the basic threshold , it means that the boundary of triggering defrosting is closer to the normal level, and the branch distribution intensity is closer to the minimum; when is relatively more obvious "tightening" (corresponding to the working condition that is more prone to frosting), the branch distribution intensity increases accordingly. The calculation formula is as follows:

[0051]

[0052] Where, is the current cycle branch heat distribution ratio; is the minimum distribution ratio of the branch when it enters defrosting, which usually corresponds to the intensity that the branch has stable heating but does not cause system mutation when it just enters defrosting. Maximum distribution ratio allowed for branch, usually defined by high pressure rise rate and main circuit heating stability during equipment commissioning; Dynamic threshold outputted in step S2; Base threshold parameter used in step S2 threshold generation, written in controller parameter table during equipment calibration / commissioning; Indicates saturation constraint operation, which can be completed by two comparisons of "max with 0 first, min with 1 second" in controller implementation, to ensure that the normalized term always falls within the controllable range. The implementation of this formula does not depend on additional sensors, but only on the existing parameter table in the controller and the output quantity in step S2, which is convenient for stable operation on the field controller.

[0053] After that, the controller maps it as "main branch valve target opening combination", and limits the change amplitude of each control period to avoid the step change of refrigerant flow caused by one-step valve. Considering that the branch is realized by an electromagnetic valve in the structure of this scheme, and the flow is adjusted by a branch electronic expansion valve; the main circuit is adjusted by a main electronic expansion valve, therefore the controller uses the following mapping relationship to generate the target opening:

[0054] ;

[0055] ;

[0056] Wherein, Branch electronic expansion valve target opening, output as opening instruction percentage given by the controller to the driver; Branch minimum opening (used to ensure continuous refrigerant flow in the branch in defrosting state, to avoid intermittent impact), Branch maximum opening (used to quickly provide defrosting heat); Main electronic expansion valve target opening; Main minimum opening, used to ensure that the main circuit continuous heating capacity is not damaged; Main reference opening at the moment of defrosting start, usually taking the main actual opening of the previous control period before entering defrosting and latching; Main-branch linkage coefficient, used to describe the "slope of the main opening when the branch opening increases", which is determined and fixed in the commissioning phase. The engineering meaning of this mapping is: the more heat the branch needs ( The larger the branch valve is opened; at the same time, the main valve is limited to not less than , to ensure that the non-stop heating always holds true.

[0057] ​To ensure the above target opening degree can be directly executed on the device, the controller will add a simple execution rhythm control before actually issuing the instruction. The action sequence of the electromagnetic valve is usually "connect first and then increase": when becomes TRUE, the controller first issues an electromagnetic valve opening instruction and maintains a short stable window (for example, several control periods), and then gradually increases the branch opening degree according to . This approach can avoid the situation where the branch expansion valve opening degree is too large when the electromagnetic valve is not fully in place, causing instantaneous flow impact. During the opening degree increment process, the controller sets a fixed step size upper limit for the opening degree change of each period, for example, the branch increases by several percentage points per period and the main road decreases by several percentage points per period. These step sizes are determined by the response speed of the valve actuator and the pressure change speed of the system, and are one-time set parameters during device debugging. If a more intuitive debugging method is required, a simple example can be used to illustrate the situation: when is TRUE for the first time and corresponding normalized urgency is about 0.6, will fall between and , and the branch target opening degree will be mapped to the medium-high opening degree interval; the controller will not reach the target at once, but will approach the target by fixed step size per cycle until and .

[0058] This step converts the dynamic threshold of step S2 into a continuously adjustable heat distribution ratio , and further maps it to the main branch valve target opening degree combination, so that the "defrosting state determination" can naturally transition to "controllable heat allocation and valve control parameter generation", thereby providing directly applicable control input for stable execution of non-stop defrosting.

[0059] S4: At the specific execution level, the controller does not directly issue the target opening degree in to the actuator as "final action", but introduces an execution rhythm control mechanism directly related to , , which represents the main branch valve control target parameter combination generated by step S3, used to describe the target opening degree state of the main road electronic expansion valve and the branch electronic expansion valve in the current control period, as well as the corresponding branch communication control instruction. The basic idea is that the stronger the defrosting demand, the faster the execution action; when the defrosting demand weakens, the execution action slows down automatically, thereby keeping consistent with the heat allocation logic in step S3. The controller reads the executed execution instruction of the last period in each control period, and calculates the new issued value of this period based on it. Taking the branch electronic expansion valve as an example, its actual issued instruction satisfies the following update relationship:

[0060] ;

[0061] in, This indicates the opening command issued to the branch electronic expansion valve driver in the current cycle; The instruction values ​​that have been executed and retained in the previous cycle are stored in the controller's internal registers; This parameter represents the maximum allowable change in valve opening within a single control cycle. It is determined and fixed during the equipment commissioning phase based on the valve's actuation speed and system pressure change characteristics. This is the defrosting heat distribution ratio output in step S3. Through this relationship, the controller can automatically adjust the operating speed of the branch valves according to the defrosting intensity without requiring additional judgment. For example, when the system has just entered the defrosting stage... When the frost level is moderate, the branch opening will gradually increase at a moderate rate; when the frost layer is heavy, As the limit approaches, the branch opening increases more rapidly, thus accelerating defrosting.

[0062] The execution scheduling of the main circuit electronic expansion valve adopts the same periodic update method as that of the branch circuit, but its target is always limited by the minimum opening constraint of the main circuit given in step S3. In specific implementation, when the controller updates the execution command of the main circuit in each cycle, it first calculates the candidate value based on the command of the previous cycle and the maximum allowable change range, and then compares it with the target range of the main circuit generated in step S3 to ensure that the actual issued command will not be lower than the lower limit required for continuous heating of the main circuit.

[0063] The execution logic of the solenoid valve is also explicitly incorporated into the scheduling process in this step. When step S3 generates... When the branch circuit enters the defrosting state, the controller first issues a solenoid valve connection command and maintains this state for several consecutive control cycles, ensuring a stable refrigerant flow path is established in the branch circuit. Only then does the opening adjustment of the branch circuit's electronic expansion valve proceed gradually according to the aforementioned control logic. This sequence is particularly important in actual equipment, preventing instantaneous flow surges caused by the branch valve opening before the solenoid valve is fully in position.

[0064] While execution control continues, the controller begins to assess whether defrosting is nearing completion. This step does not reintroduce a complex state-determination model, but instead utilizes existing execution intensity metrics. Together with the stability of the heat exchange state, this constitutes the exit judgment. The controller generates a defrost exit flag according to the following rules:

[0065] ;

[0066] in, This indicates the defrost termination determination result for the current cycle; the branch heat allocation ratio outputted in step S3; the minimum defrosting allocation ratio defined in step S3; "fin state stable recovery" means that the fin surface temperature and the system operating state are kept in the normal heat exchange interval, and the system pressure does not show a continuous rising trend in a continuous number of control cycles. The actual implementation of this determination is: the controller internally sets a counter, which is incremented when the above conditions are continuously met, and is set to TRUE when the preset number of times is reached, so as to avoid misjudgment of defrosting completion due to short-term fluctuations.

[0067] When is TRUE, the controller enters the defrosting exit scheduling process. This process is opposite to the execution logic direction when entering defrosting: the actual issued instructions of the branch electronic expansion valve are gradually reduced according to the same rhythm control relationship as before, until returning to the minimum or closed state; then the solenoid valve is closed, cutting off the branch refrigerant flow path; the main road electronic expansion valve remains continuously adjusted throughout the process, and finally completely hands over to the normal heating control logic. Since the exit process is still constrained by and the execution step limit, the entire rollback process is smooth and continuous in time, and will not cause sudden changes in heating capacity. The output of this step is limited to two quantities: one is the execution instruction set actually issued by the controller, used to directly drive the main road and branch valves and the solenoid valve; the other is the defrosting exit flag , used to identify whether this defrosting process is completed and trigger the system state switching.

[0068] The embodiment of the application also provides a kind of for air source heat pump collaborative frost prevention and not shutdown defrosting intelligent control equipment, including processor, memory and storage in the memory and be configured to be executed by the computer program of processor, the processor executes the computer program when realizing the step in the above described one for air source heat pump collaborative frost prevention and not shutdown defrosting intelligent control method embodiment, for example Figure 1 The steps S1~S4 described in the step S1~S4;Or, the processor executes the computer program when realizing the function of each module in each system embodiment.

[0069] Illustratively, the computer program can be divided into one or more modules, the one or more modules are stored in the memory and executed by the processor to complete the application. The one or more modules can be a series of computer program instruction segments capable of completing a specific function, which is used to describe the execution process of the computer program in the one for air source heat pump collaborative frost prevention and not shutdown defrosting intelligent control equipment.

[0070] ​The computer device can be a desktop computer, a notebook computer, a palm computer, a cloud server, or the like. The computer device can include, but is not limited to, a processor, a memory, an input / output device, a network access device, a bus, and the like.

[0071] The processor can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The processor is a control center of the computer device, and connects all parts of the computer device through various interfaces and lines.

[0072] The memory can be used to store the computer program and / or the module, and the processor realizes various functions of the computer device by running or executing the computer program and / or the module stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area. The program storage area can store an operating system, at least one application required by a function, and the like; and the data storage area can store data created according to the running of the air conditioner controller, and the like. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, for example, a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one disk storage device, a flash memory device, or other volatile solid-state memory devices.

[0073] If the module for the air source heat pump is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware. The computer program can be stored in a computer readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable files or some intermediate forms, etc. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0074] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware. The program can be stored in a computer readable storage medium. When the program is executed, it can include the processes of the above-mentioned various method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0075] The above is the preferred embodiment of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which are also considered within the scope of protection of the present application.

Claims

1. A coordinated frost prevention and non-stop defrosting intelligent control system for an air source heat pump, characterized in that, The system comprises: A frost trend identification module is configured to periodically collect the evaporative side temperature, the ambient temperature and the ambient relative humidity, calculate the current evaporative temperature difference, and perform a weighted trend estimation on the evaporative temperature difference based on a sliding time window to obtain a temperature difference trend estimation value, and further calculate a trend deviation amount; when the frost trend identification module performs the weighted trend estimation on the evaporative temperature difference based on the sliding time window, the sliding time window covers consecutive sampling periods, and the weight coefficient of each historical sampling point in the window monotonically decreases with the increase of the time interval between the sampling time of the historical sampling point and the current sampling time; A dynamic defrosting determination module is communicatively connected to the frost trend identification module, configured to dynamically adjust a defrosting determination threshold based on the trend deviation amount, and generate a defrosting state flag in combination with the evaporative temperature difference and the dynamically adjusted defrosting determination threshold; A heat distribution control module is communicatively connected to the dynamic defrosting determination module, configured to determine a branch heat distribution ratio according to the dynamically adjusted defrosting determination threshold when the defrosting state flag is valid, and generate a main circuit electronic expansion valve target opening degree and a branch electronic expansion valve target opening degree; when the heat distribution control module calculates the main circuit electronic expansion valve target opening degree, the calculation is based on a main circuit reference opening degree locked before defrosting starts, a branch electronic expansion valve target opening degree increment and a main-branch linkage coefficient, and the main circuit electronic expansion valve target opening degree is limited to be not lower than a main circuit minimum opening degree; A defrosting execution and exit module is communicatively connected to the heat distribution control module, configured to gradually adjust the branch electronic expansion valve opening degree to the branch electronic expansion valve target opening degree at a defined change rate after the electromagnetic valve is turned on, while maintaining the main circuit electronic expansion valve opening degree in a range not lower than the main circuit minimum opening degree; and when the branch heat distribution ratio is equal to a minimum defrosting distribution ratio and the fin heat exchange state remains stable within a continuous control period, generate a defrosting exit flag, and gradually close the branch electronic expansion valve and the electromagnetic valve at a defined change rate; The system is provided with a main circuit refrigerant channel and a branch refrigerant channel which are independent of each other, the main circuit refrigerant channel is provided with a main circuit electronic expansion valve, the branch refrigerant channel is provided with a branch electronic expansion valve and an electromagnetic valve, and the electromagnetic valve is used to control the on-off of the branch refrigerant channel.

2. The intelligent control system for simultaneous frost prevention and defrosting without shutdown of the air source heat pump according to claim 1, characterized in that, The evaporative side temperature used by the frost trend identification module is obtained by a temperature sensor at the outlet of the main circuit refrigerant channel, and the ambient temperature and the ambient relative humidity are obtained by a sensor at the air inlet side of the composite fin heat exchanger.

3. The intelligent control system for simultaneous anti-frost and frost-healing without shutdown of the air source heat pump according to claim 1, characterized in that, When the dynamic defrosting determination module adjusts the defrosting determination threshold, the defrosting determination threshold of the last period, a basic threshold, the trend deviation amount and a threshold inertia coefficient are fused to make the threshold change smoothly with the frost trend.

4. The intelligent control system for simultaneous anti-frosting and frost-healing without shutdown of the air source heat pump according to claim 1, characterized in that, When the dynamic defrosting determination module generates the defrosting state flag, a one-sided weighting term is introduced only when the trend deviation amount is negative to tighten the triggering condition, and the condition is required to be established within consecutive sampling periods before being set to valid.

5. The intelligent control system for simultaneous anti-frost and frost-healing without shutdown of the air source heat pump according to claim 1, characterized in that, The heat distribution control module obtains the branch heat distribution ratio by linearly mapping a normalized difference between the dynamically adjusted defrosting determination threshold and the basic threshold to between a preset minimum distribution ratio and a maximum distribution ratio.

6. The intelligent control system for simultaneous anti-frost and frost-healing without shutdown of the air source heat pump according to claim 1, characterized in that, The defrosting execution and exit module limits the adjustment range of the branch electronic expansion valve opening degree and the main circuit electronic expansion valve opening degree to not more than a preset maximum change step in each control cycle.

7. The intelligent control system for simultaneous anti-frost and frost-healing without shutdown of the air source heat pump according to claim 1, characterized in that, When the defrosting execution and exit module generates a defrosting exit flag, the following conditions need to be met simultaneously: the branch heat distribution ratio is equal to the minimum defrosting distribution ratio, and the fin surface temperature and the system pressure remain stable and have no continuous rising trend in the continuous control cycle.

8. The intelligent control system for simultaneous anti-frosting and frost-healing of air source heat pump of claim 1, wherein, The defrosting execution and exit module delays the adjustment of the branch electronic expansion valve opening degree for a stable window after the control solenoid valve is turned on, so as to suppress the instantaneous impact of the refrigerant flow.

Images