A segmented heat pump defrost control method and heat pump system

Abstract

The application provides a segmented heat pump defrosting control method and a heat pump system, the method comprising: acquiring outdoor environment parameters, compressor parameters, indoor side load parameters, and coil temperature parameters and air volume parameters of each heat exchange section; determining the predicted remaining time for the outdoor heat exchanger to reach a preset critical frosting state according to the multiple source operating parameters; and triggering defrosting when the predicted remaining time is less than a preset advance amount. During the defrosting process, the four-way valve is kept in the heating position, part of the refrigerant discharged by the compressor is selectively delivered to the current defrosting heat exchange section through a bypass shunt circuit, and the bypass refrigerant flow, the heat exchange section air volume and the compressor operating frequency are coordinately adjusted according to the coil temperature parameters, the indoor side load parameters and the exhaust gas parameters, and each heat exchange section completes defrosting in turn. The application can improve the foresight and accuracy of defrosting triggering, reduce the heat supply interruption and reversing impact caused by reverse cycle defrosting, and improve the continuity, stability and overall energy efficiency of the defrosting process.

Description

Technical Field

[0001] This invention belongs to the field of air source heat pump technology, and in particular relates to a segmented heat pump defrosting control method and a heat pump system. Background Technology

[0002] When an air source heat pump operates in a low-temperature, high-humidity environment, frost formation on the outdoor heat exchanger surface increases heat exchange resistance and airflow resistance, leading to decreased system efficiency and, in severe cases, affecting operational stability. Therefore, accurately assessing the frost formation and defrosting promptly is crucial for ensuring the reliable and efficient operation of the heat pump.

[0003] Currently, existing heat pump systems typically determine defrosting timing based on one or a few parameters such as operating time, coil temperature, coil temperature change rate, or a combination of pressure and temperature. This method is easily affected by changes in the environment and operating conditions, and generally suffers from trigger lag or false triggering, resulting in a mismatch between the defrosting timing and the actual frost condition.

[0004] To improve accuracy, some solutions introduce multiple operating parameters or data-driven models to identify frost conditions. However, such improvements are still limited to the trigger-based judgment level. Once triggered, the system executes traditional reverse-cycle defrosting, requiring the switching of the four-way valve to allow high-temperature exhaust gas to enter the outdoor heat exchanger. This process not only leads to a significant reduction or even interruption of indoor heating but also causes pressure fluctuations and refrigerant migration issues due to the four-way valve reversal.

[0005] To avoid heating interruptions, another solution uses compressor exhaust bypass to defrost without reversing the flow. However, in this method, the bypass refrigerant flow is fixed or adjusted according to a rough rule, making it difficult to match the actual degree of frost formation, which can easily lead to insufficient defrosting heat or localized overheating. Especially when the outdoor heat exchanger has a segmented structure, existing segmented defrosting often follows a fixed timing or preset sequence, without considering the differences in frost formation in each segment. Furthermore, there is a lack of coordinated adjustment between fan speed, bypass flow, and indoor heating load, resulting in large fluctuations in system operation and low defrosting efficiency. Therefore, there is an urgent need for a heat pump defrosting control method that can predict frost trends in advance based on multi-source operating parameters, implement segmented bypass defrosting while maintaining heating operation, and coordinate the bypass refrigerant flow, air volume, and indoor load. Summary of the Invention

[0006] In view of this, the present invention provides a segmented heat pump defrosting control method and a heat pump system to solve the problems of delayed or false defrosting triggering, interruption of indoor heating during defrosting, and large fluctuations in system operation during the defrosting process in the prior art.

[0007] A first aspect of the present invention provides a segmented heat pump defrosting control method applied to a heat pump system. The heat pump system includes a main circuit, a bypass circuit, and an outdoor heat exchanger having multiple heat exchange sections connected in parallel. The main circuit includes a compressor and a four-way valve. The airflow of each heat exchange section can be independently adjusted. The bypass circuit is used to selectively deliver a portion of the refrigerant discharged from the compressor to each heat exchange section. The method includes: The multi-source operating parameters of the heat pump system are obtained. The multi-source operating parameters include at least outdoor environmental parameters, compressor parameters, indoor load parameters, and coil temperature and air volume parameters of each heat exchange section. The compressor parameters include the operating frequency and exhaust parameters of the compressor. Based on the multi-source operating parameters, determine the estimated remaining time for the outdoor heat exchanger to reach the preset critical frosting state; When the estimated remaining time is less than the preset advance amount, the current defrosting cycle is triggered, and the four-way valve is kept in the heating position during the current defrosting cycle. Each heat exchange section is designated as the current defrost heat exchange section, and a portion of the refrigerant discharged from the compressor is selectively delivered to the current defrost heat exchange section via the bypass diversion circuit. During the defrosting process of the current defrosting heat exchange section, the bypass refrigerant flow rate entering the current defrosting heat exchange section, the air volume of the current defrosting heat exchange section, and the operating frequency of the compressor are coordinated and adjusted according to the coil temperature parameters of the current defrosting heat exchange section, the indoor load parameters, and the exhaust parameters. After the current defrosting heat exchange section meets the defrosting completion conditions, the other heat exchange section that has not yet completed this round of defrosting is designated as the new current defrosting heat exchange section and defrosting is performed until all heat exchange sections have completed this round of defrosting.

[0008] A second aspect of the present invention provides a heat pump system including a controller, a main circuit, a bypass circuit, and an outdoor heat exchanger having multiple heat exchange sections arranged in parallel. The main circuit includes a compressor and a four-way valve. The airflow of each heat exchange section can be independently adjusted. The bypass circuit is used to selectively deliver a portion of the refrigerant discharged by the compressor to each heat exchange section. The controller is configured to perform the segmented heat pump defrosting control method as described in the first aspect.

[0009] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: This invention predicts the estimated remaining time to reach the critical frosting state based on multi-source operating parameters such as outdoor environment, coil temperature, compressor, and indoor load. This allows for defrosting to be triggered before the frost layer reaches the critical state, reducing excessive frost thickness and ineffective defrosting caused by judgment lag, and improving the accuracy and foresight of defrosting triggering. Simultaneously, during defrosting, the four-way valve remains in the heating position, and a portion of the compressor exhaust is selectively delivered to each heat exchange section for segmented defrosting via a bypass diversion circuit. This avoids heating interruptions and reversing shocks caused by traditional reverse-cycle defrosting. By coordinating the bypass refrigerant flow rate, heat exchange section air volume, and compressor operating frequency, it can also balance defrosting needs with indoor heating load, reducing defrosting energy consumption and system operational fluctuations, and improving the continuity, stability, and overall energy efficiency of the defrosting process. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of a heat pump system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a segmented heat pump defrosting control method provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a parameter coordinated adjustment method provided in an embodiment of the present invention. Detailed Implementation

[0012] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will recognize that the present application may be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted to avoid unnecessary detail that could obscure the description of the present application.

[0013] The technical solution of the present invention will be illustrated below through specific embodiments.

[0014] This invention provides a segmented heat pump defrosting control method, applied to heat pump systems. Figure 1 This is a schematic diagram of a heat pump system, such as... Figure 1As shown, the segmented heat pump defrost control heat pump system includes a main circuit (shown as specific components in the figure), a bypass diversion circuit 13, and an outdoor heat exchanger 12 with multiple parallel heat exchange sections 121. The main circuit includes a compressor 10 and a four-way valve 11. The airflow of each heat exchange section 121 can be independently adjusted. The bypass diversion circuit 13 is used to selectively deliver a portion of the refrigerant discharged from the compressor 10 to each heat exchange section 121. Figure 1 As shown, the main circuit also includes an indoor heat exchanger 14, an electronic expansion valve 15, and a gas-liquid separator 16. In addition, the heat pump system also includes a controller ( Figure 1 (Not shown). It should be noted that, Figure 1 The structure shown is merely an example, and the number of heat exchange sections 121 in the indoor heat exchanger 12 is also an example.

[0015] In heating operation, the four-way valve 11 is in the heating position, and the bypass circuit 13 is in the closed state, not participating in refrigerant diversion. The compressor 10 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant, which is then sent to the indoor heat exchanger 14 via the four-way valve 11. In the indoor heat exchanger 14, the high-temperature, high-pressure refrigerant exchanges heat with indoor air or water, condensing and releasing heat to continuously supply heat to the room. The condensed high-pressure liquid refrigerant is throttled and depressurized by the electronic expansion valve 15, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which then enters the heat exchange sections 121 of the outdoor heat exchanger 12. Under the action of the outdoor fan, ambient air flows through the heat exchange sections 121, and the refrigerant absorbs heat from the air and evaporates into a low-pressure gaseous refrigerant. It then enters the gas-liquid separator 16 via the four-way valve 11, separating any liquid refrigerant it may be carrying before returning to the suction side of the compressor 10, completing the heating cycle.

[0016] In this embodiment, as Figure 2 The diagram illustrates a segmented heat pump defrosting control method, which is executed by the controller of the heat pump system and may specifically include the following steps: S21. Obtain multi-source operating parameters of the heat pump system.

[0017] Multi-source operating parameters include at least outdoor environmental parameters, compressor parameters, indoor load parameters, and coil temperature and air volume parameters for each heat exchange section. Compressor parameters include compressor operating frequency and exhaust parameters.

[0018] During the operation of the heat pump system, the controller acquires multi-source operating parameters according to a preset sampling period. These multi-source operating parameters include at least outdoor environmental parameters, compressor parameters, indoor load parameters, and coil temperature and air volume parameters for each heat exchange section.

[0019] Among them, the outdoor environmental parameters are used to characterize the frosting conditions of the environment in which the heat pump system is located, and may include ambient temperature and relative humidity; the compressor parameters are used to characterize the operating status of the compressor and refrigerant cycle, and may include the compressor operating frequency and exhaust parameters, which may include exhaust pressure and exhaust temperature; the indoor load parameters are used to characterize the current indoor heating demand, and may include at least one of supply water temperature, return water temperature, and supply air temperature; the coil temperature parameters are used to characterize the heat exchange and frosting changes of the corresponding heat exchange section; and the air volume parameters are used to characterize the air-side operation of the corresponding heat exchange section, and may be obtained based on the operating status of the corresponding fan.

[0020] The controller can perform noise reduction, outlier processing, and normalization on the acquired multi-source operating parameters to form multi-dimensional operating features for subsequent frost state prediction.

[0021] S22. Based on the multi-source operating parameters, determine the estimated remaining time for the outdoor heat exchanger to reach the preset critical frosting state.

[0022] Based on the multi-source operating parameters obtained in step S21, the controller predicts the frosting development trend of the outdoor heat exchanger and determines the estimated remaining time required for the outdoor heat exchanger to develop from its current operating state to a preset critical frosting state. This can be achieved using a pre-trained frosting prediction model. The actual frosting thickness and defrosting events are labeled in historical operating data, and the mapping relationship between the multi-source operating parameters and the estimated remaining time is obtained through offline training, thus creating the Long Short-Term Memory (LSTM) network model. Inputting the multi-source operating parameters into the model yields the corresponding estimated remaining time.

[0023] The preset critical frost state is used to characterize the degree of frost when defrosting needs to be activated. It can be calibrated in advance through experiments and stored in the controller.

[0024] By determining the estimated remaining time to reach the preset critical frosting state, the defrosting requirement can be judged before the outdoor heat exchanger actually reaches the critical frosting state, thus avoiding the need to make defrosting judgments based solely on parameters such as the current coil temperature and running time.

[0025] In an optional embodiment, the frost prediction model is built and deployed as follows: Data preprocessing: Outlier filtering is performed on the collected multi-source operating parameter time series data to remove jump data at the moment of compressor start-up and shutdown, the moment of defrosting end, as well as null values ​​and infinite values ​​caused by sensor failure; Min-Max normalization is used to scale each feature to the [0,1] interval, and the normalization parameters are taken from the training set and fixed in the controller; the training set, validation set and test set are divided into three sets according to the proportions of 70%, 15% and 15%, respectively.

[0026] Model Structure: A two-layer LSTM network is used. The input consists of temporal features of multi-source running parameters from multiple consecutive sampling periods. The first LSTM layer contains 128 neurons and outputs the complete sequence. After a Dropout layer with a dropout rate of 0.2, the second LSTM layer contains 64 neurons and outputs the hidden state of the last time step. After another Dropout layer with a dropout rate of 0.2 and a ReLU fully connected layer with 32 neurons, the prediction result is output by the output layer. The loss function is mean squared error, the optimizer is Adam, the initial learning rate is 0.001, and the ReduceLROnPlateau strategy is adopted.

[0027] Training and validation: The batch size was set to 64, the training epochs were set to 500, and an early stopping mechanism was adopted, which terminated training when the validation set loss did not decrease for 50 consecutive epochs. The model performance was evaluated by mean absolute error, goodness of fit, false positive rate, and false negative rate.

[0028] Quantization and Deployment: The trained model is pruned and INT8 fixed-point quantized, converted into C code via TFLM and integrated into the heat pump main control firmware; the controller collects real-time data at a set period, processes it with the same normalization, inputs it into the model for online inference, and outputs frost prediction results for defrosting decision-making.

[0029] S23. When the estimated remaining time is less than the preset advance amount, trigger the current defrost cycle and keep the four-way valve in the heating position during the current defrost cycle.

[0030] The controller compares the estimated remaining time obtained in step S22 with a preset lead time. When the estimated remaining time is greater than or equal to the preset lead time, the heat pump system maintains normal heating operation and continues to acquire multi-source operating parameters and update the estimated remaining time. When the estimated remaining time is less than the preset lead time, the controller triggers the current defrost cycle. Optionally, the preset lead time is greater than the duration required for the current defrost cycle.

[0031] During this defrosting process, the four-way valve remains in the heating position and does not perform a reversing operation, thus keeping the main circuit in heating operation and avoiding indoor heating interruption and system pressure fluctuation caused by the reversing of the four-way valve during traditional reverse circulation defrosting.

[0032] S24. Each heat exchange section is designated as the current defrost heat exchange section, and a portion of the refrigerant discharged from the compressor is selectively transported to the current defrost heat exchange section via a bypass diversion circuit.

[0033] During this defrosting process, the controller determines the current defrosting heat exchange section from among the multiple heat exchange sections of the outdoor heat exchanger and controls the bypass diversion circuit to connect with the current defrosting heat exchange section. This allows a portion of the high-temperature refrigerant discharged from the compressor to enter the current defrosting heat exchange section via the bypass diversion circuit, utilizing the heat carried by this portion of the high-temperature refrigerant to defrost the current defrosting heat exchange section. For example... Figure 1 As shown, when the current defrost heat exchange section is determined, the one-way valve 132 connected to the current defrost heat exchange section is opened, while the other one-way valves remain closed. This allows a portion of the high-temperature refrigerant discharged from the compressor 10 to be transported to the current defrost heat exchange section via the bypass diversion circuit 13.

[0034] During the process of supplying bypass refrigerant to the current defrost heat exchange section, the four-way valve remains in the heating position, and the main circuit continues to operate. Sections other than the current defrost heat exchange section do not receive high-temperature refrigerant supplied by the bypass branch circuit and continue to participate in the heating and heat exchange process of the heat pump system.

[0035] Using the above method, defrosting can be performed on each heat exchange section of the outdoor heat exchanger while maintaining the heating operation of the heat pump system. Each heat exchange section can be selected as the current defrosting section, either sequentially according to their arrangement or by choosing any undefrosted section. The specific method can be determined based on actual needs.

[0036] In an optional embodiment, the coil temperature parameters include coil temperature change parameters; each heat exchange section is designated as the current defrost heat exchange section, including: Based on the coil temperature change parameters of each heat exchange section, the defrosting priority of each heat exchange section is determined. Among them, the coil temperature change parameters include the coil temperature change slope, and the defrosting priority is positively correlated with the absolute value of the coil temperature change slope. According to the defrosting priority, each heat exchange section is determined as the current defrosting heat exchange section.

[0037] The slope of the coil temperature change reflects the temperature trend of the corresponding heat exchange section under current operating conditions and is used to characterize the frosting development of that section. In this embodiment, the larger the absolute value of the coil temperature change slope, the higher the degree of frosting in the corresponding heat exchange section, thus assigning a higher defrosting priority to that section. The controller can sequentially determine each heat exchange section as the current defrosting section according to the defrosting priority from high to low, prioritizing defrosting of heat exchange sections with higher degrees of frosting.

[0038] For example, when an outdoor heat exchanger includes a first heat exchange section, a second heat exchange section, and a third heat exchange section, and the absolute values ​​of the corresponding coil temperature change slopes satisfy the condition that the first heat exchange section is greater than the second heat exchange section, and the second heat exchange section is greater than the third heat exchange section, defrosting can be performed sequentially in the order of the first heat exchange section, the second heat exchange section, and the third heat exchange section. After the previous heat exchange section has been defrosted, the next heat exchange section is determined as the current defrosting heat exchange section according to the defrosting priority.

[0039] S25. During the defrosting process of the current defrosting heat exchange section, the bypass refrigerant flow rate entering the current defrosting heat exchange section, the air volume of the current defrosting heat exchange section, and the operating frequency of the compressor are adjusted in a coordinated manner based on the coil temperature parameters, indoor load parameters, and exhaust parameters of the current defrosting heat exchange section.

[0040] Specifically, the controller adjusts the bypass refrigerant flow rate entering the current defrost heat exchange section based on the coil temperature parameters of the current defrost heat exchange section and the compressor's discharge parameters, so that the bypass refrigerant flow rate is adapted to the frosting condition of the current defrost heat exchange section and the compressor's current operating conditions.

[0041] At the same time, the controller adjusts the air volume of the current defrost heat exchange section and the non-current defrost heat exchange section to coordinate the defrosting heat provided by the bypass refrigerant with the air-side heat exchange state of each heat exchange section.

[0042] The controller also adjusts the compressor's operating frequency based on indoor load parameters, ensuring that the heat pump system maintains indoor heating demand while performing segmented defrosting. When the compressor's operating frequency changes, its discharge pressure and / or discharge temperature change accordingly, allowing the controller to further adjust the bypass refrigerant flow rate entering the current defrosting heat exchange section based on the changed discharge parameters.

[0043] This allows the bypass refrigerant flow, the air volume of each heat exchange section, and the compressor operating frequency to be coordinated and adjusted during the defrosting process, so as to take into account the defrosting needs of the current heat exchange section, the heating and heat exchange of the non-current heat exchange section, and the indoor heating needs.

[0044] S26. After the current defrosting heat exchange section meets the defrosting completion conditions, the other heat exchange section that has not yet completed this round of defrosting shall be taken as the new current defrosting heat exchange section and defrosting shall be carried out until all heat exchange sections have completed this round of defrosting.

[0045] The controller continuously determines whether the defrosting completion conditions are met during the defrosting process in the current defrosting heat exchange section.

[0046] In one alternative implementation, defrosting completion conditions may include at least one of the following: (1) The coil temperature of the current defrosting heat exchange section has reached the preset exit temperature. When the frost melts, the coil temperature is around 0°C (ice-water mixture). When the frost has completely melted, the high-temperature refrigerant continues to heat, and the coil temperature will rise rapidly. When the temperature rises to a certain set value (e.g., 12°C), it means that defrosting is complete.

[0047] (2) The current trend of the coil temperature change in the defrosting heat exchange section meets the preset defrosting completion conditions. For example, the coil temperature change slope changes from negative to positive and continues to exceed 0.5℃ / min for more than 2 minutes; when frosting, the coil temperature decreases and the slope is negative; when defrosting, the temperature begins to rise and the slope is positive; if the temperature continues to rise for more than 2 minutes at a rate of more than 0.5℃ / min, it indicates that defrosting is complete.

[0048] (3) The current defrosting heat exchange section has reached the preset maximum allowable time. In case the sensor fails or the weather is extremely bad, the above two conditions cannot be met. Therefore, a maximum time limit (e.g., 3 minutes) is set to avoid the bypass valve from working for a long time.

[0049] When the current defrost heat exchange section meets the defrost completion conditions, stop supplying the bypass refrigerant for the current defrost process to that heat exchange section, and designate the other heat exchange section that has not yet completed this round of defrost as the new current defrost heat exchange section, and execute steps S24 and S25 again.

[0050] Defrost each heat exchange section one by one in the manner described above until each heat exchange section has completed its defrosting cycle. After each heat exchange section has completed its defrosting cycle, the controller ends the current round of segmented defrosting and controls the heat pump system to return to normal heating operation. After the current round of defrosting is completed, the bypass proportional regulating valve is gradually closed, for example, by gradually closing it over 30 to 60 seconds to avoid sudden changes in system pressure. All outdoor fans are restored to normal heating speed; the compressor frequency and the main circuit electronic expansion valve are restored to near their steady-state operating points before defrosting; then step S21 is executed again to restart the next round of frosting monitoring and prediction.

[0051] This invention predicts the estimated remaining time to reach the critical frosting state based on multi-source operating parameters such as outdoor environment, coil temperature, compressor, and indoor load. This allows for defrosting to be triggered before the frost layer reaches the critical state, reducing excessive frost thickness and ineffective defrosting caused by judgment lag, and improving the accuracy and foresight of defrosting triggering. Simultaneously, during defrosting, the four-way valve remains in the heating position, and a portion of the compressor exhaust is selectively delivered to each heat exchange section for segmented defrosting via a bypass diversion circuit. This avoids heating interruptions and reversing shocks caused by traditional reverse-cycle defrosting. By coordinating the bypass refrigerant flow rate, heat exchange section air volume, and compressor operating frequency, it can also balance defrosting needs with indoor heating load, reducing defrosting energy consumption and system operational fluctuations, and improving the continuity, stability, and overall energy efficiency of the defrosting process.

[0052] In an optional embodiment, the exhaust parameters include exhaust pressure and exhaust temperature; such as Figure 3The diagram illustrates a parameter coordination adjustment method. Based on the coil temperature parameters, indoor load parameters, and exhaust parameters of the current defrost heat exchange section, the bypass refrigerant flow rate entering the current defrost heat exchange section, the air volume of the current defrost heat exchange section, and the compressor operating frequency are coordinated and adjusted (S25). This includes: S251. Based on the coil temperature parameters of the current defrost heat exchange section, determine the equivalent frosting degree of the current defrost heat exchange section, and based on the equivalent frosting degree and exhaust parameters, determine the bypass refrigerant flow rate entering the current defrost heat exchange section.

[0053] The equivalent frost level is used to characterize the frost accumulation in the current defrosting heat exchange section from the last defrosting to the current moment. Coil temperature parameters can include coil temperature change parameters, such as the coil temperature change slope. Parameters used to characterize frost growth can be determined based on the coil temperature change parameters and a preset correspondence, thereby obtaining the equivalent frost level of the current defrosting heat exchange section.

[0054] When determining the bypass refrigerant flow rate, the equivalent frosting level of the current defrosting heat exchange section, as well as the compressor's discharge pressure and temperature, can be considered comprehensively. On the one hand, a higher equivalent frosting level indicates a greater defrosting demand in the current defrosting heat exchange section, which can correspondingly increase the bypass refrigerant flow rate entering the current defrosting heat exchange section. On the other hand, discharge pressure and discharge temperature reflect the compressor's current discharge status. Correcting the bypass refrigerant flow rate using discharge parameters can avoid a mismatch between the bypass refrigerant quantity and the compressor's actual operating conditions caused by determining the bypass refrigerant flow rate solely based on the frosting level.

[0055] S252. Obtain the power of the compressor and the total power of the corresponding fans in each heat exchange section, and adjust the air volume of each heat exchange section according to the bypass refrigerant flow rate, exhaust parameters, compressor power and total fan power.

[0056] During defrosting in the current defrosting heat exchange section, the airflow of each heat exchange section can be adjusted independently. By adjusting the airflow of the current defrosting heat exchange section, the heat exchange state on the air side of that section can be changed, allowing more of the heat provided by the bypass refrigerant to be used for defrosting. At the same time, by adjusting the airflow of non-current defrosting heat exchange sections, the heating capacity of non-current defrosting heat exchange sections can be maintained, thus balancing the defrosting needs of the current heat exchange section with the continuous heating needs of the heat pump system.

[0057] To ensure that airflow adjustment takes into account both defrosting effect and system energy consumption, a defrosting energy efficiency index can be established to evaluate the current airflow combination based on the defrosting capacity reflected by the bypass refrigerant and the operating power of the compressor and fan. The airflow of each heat exchange section can then be adjusted according to changes in the defrosting energy efficiency index.

[0058] For example, an equivalent defrosting evaluation index can be determined based on the bypass refrigerant flow rate and the temperature difference between the exhaust and return air temperatures. This index can then be combined with the compressor power and the total fan power to determine the defrosting energy efficiency factor. When the defrosting energy efficiency factor indicates that the defrosting effect corresponding to the current airflow combination is reduced relative to the operating energy consumption, the airflow of the current defrosting heat exchange section and / or non-current defrosting heat exchange sections can be further adjusted.

[0059] S253. Adjust the compressor's operating frequency according to the indoor load parameters, and correct the bypass refrigerant flow rate based on the exhaust parameters obtained after adjusting the operating frequency.

[0060] Indoor load parameters characterize the actual heating demand during defrosting, and may include, for example, the actual water supply temperature, the actual air supply temperature, and the corresponding target temperature. The controller can adjust the compressor's operating frequency based on the deviation between the actual indoor heating state and the target heating state. For example, when the actual heating capacity is lower than the target heating demand, the compressor's operating frequency can be increased; when the actual heating capacity is higher than the target heating demand, the compressor's operating frequency can be decreased to maintain the indoor heating state within the target range.

[0061] Since changes in compressor operating frequency cause changes in discharge pressure and discharge temperature, and the discharge state affects the refrigerant state that the bypass diversion circuit can provide to the current defrost heat exchange section, after adjusting the compressor operating frequency, the compressor discharge pressure and discharge temperature are re-acquired, and the bypass refrigerant flow rate is corrected based on the re-acquired discharge parameters.

[0062] Furthermore, during the continuous defrosting process in the current defrosting heat exchange section, the equivalent degree of frost will also change with the defrosting process. Therefore, the bypass refrigerant flow can be dynamically updated by combining the updated equivalent degree of frost and the exhaust parameters after the operating frequency is adjusted, so that the bypass refrigerant flow can simultaneously adapt to the real-time defrosting requirements of the current defrosting heat exchange section and the real-time operating conditions of the compressor.

[0063] This embodiment enables a coordinated control relationship between the frosting condition of the current defrosting heat exchange section, the heating capacity of the bypass refrigerant, the air-side heat exchange status of each heat exchange section, and the indoor heating demand. This improves the defrosting efficiency of the current heat exchange section while maintaining the heating operation of the main circuit, and reduces the impact of the defrosting process on the indoor heating status and the operational stability of the heat pump system.

[0064] In one optional implementation, the coil temperature parameter includes the coil temperature change parameter, which includes the coil temperature change slope. Based on the current coil temperature parameters of the defrost heat exchange section, determine the equivalent degree of frost formation in the current defrost heat exchange section (S251), including: Based on the slope of the coil temperature change and the preset mapping relationship, the equivalent frost degree change rate of the current defrosting heat exchange section is determined; taking the equivalent frost degree corresponding to the last defrosting of the current defrosting heat exchange section as the initial value, the equivalent frost degree change rate is integrated over time to obtain the current equivalent frost degree of the current defrosting heat exchange section.

[0065] First, based on the current coil temperature of the defrosting heat exchange section obtained through continuous sampling, the coil temperature change slope is determined. This slope characterizes the trend of coil temperature change over time. During heat pump heating operation, as frost gradually increases on the surface of the heat exchange section, the heat transfer resistance generated by the frost layer and the air flow resistance change accordingly, which are reflected in the trend of coil temperature change. Therefore, the coil temperature change slope can be used to characterize the frost development of the corresponding heat exchange section.

[0066] Furthermore, based on the coil temperature change slope and a preset mapping relationship, the equivalent rate of change of frost degree in the current defrosting heat exchange section is determined. The preset mapping relationship is used to establish the correspondence between the coil temperature change characteristics and the degree of frost growth, thereby converting the coil temperature change slope into an equivalent rate of change of frost degree that reflects the rate of frost accumulation. The preset mapping relationship can be predetermined and stored in the controller, and its specific form can be set according to the operating characteristics of the heat pump system.

[0067] Using the equivalent frost level corresponding to the last defrost completion of the current defrost heat exchange section as the initial value, the rate of change of the equivalent frost level is integrated over time to obtain the equivalent frost level at the current moment. Specifically, after the current defrost heat exchange section completes one defrost cycle, it can be considered that the frost in that heat exchange section has been basically cleared, and the equivalent frost level at that moment is set as the initial value, for example, set to zero or close to zero; during subsequent heating operation, the rate of change of the equivalent frost level is continuously determined based on the slope of the coil temperature change, and this rate of change is accumulated to update the equivalent frost level of the heat exchange section.

[0068] It should be noted that the equivalent frosting degree is used to characterize the relative frosting accumulation state of the heat exchange section, and it is not limited to the actual frost thickness directly measured by the thickness sensor. By mapping and integrating the coil temperature change parameters, the frosting degree of each heat exchange section can be continuously estimated using the existing temperature detection information of the heat pump system, providing a control basis for dynamically determining the bypass refrigerant flow rate based on the current frosting demand.

[0069] In an optional embodiment, the bypass shunt circuit includes a proportional bypass valve; Based on the equivalent degree of frosting and exhaust parameters, determine the bypass refrigerant flow rate (S251) entering the current defrost heat exchange section, including: Obtain the preset critical frosting degree threshold and the preset basic bypass opening; determine the ratio between the equivalent frosting degree and the preset critical frosting degree threshold; determine the exhaust parameter correction factor based on the exhaust pressure and exhaust temperature; determine the target opening of the proportional bypass valve by multiplying the preset basic bypass opening, the ratio, and the exhaust parameter correction factor; control the proportional bypass valve according to the target opening to adjust the bypass refrigerant flow rate entering the current defrosting heat exchange section.

[0070] The preset critical frosting threshold is used to characterize the equivalent frosting level when the heat exchange section reaches the point where defrosting is required; the preset basic bypass opening is used to characterize the proportional bypass valve opening under the baseline exhaust state when the current defrosting heat exchange section reaches the preset critical frosting level. The preset critical frosting threshold and the preset basic bypass opening can be pre-calibrated according to the operating characteristics of the heat pump system and stored in the controller.

[0071] Furthermore, the ratio between the equivalent degree of frost formation in the current defrosting heat exchange section and the preset critical frost formation threshold is determined. This ratio characterizes the relative degree of frost formation in the current defrosting heat exchange section relative to the critical frost formation state. As the equivalent degree of frost formation increases, the ratio increases accordingly, indicating that the defrosting capacity required for the current defrosting heat exchange section is correspondingly increased.

[0072] Furthermore, a discharge parameter correction factor is determined based on the compressor's discharge pressure and temperature. This correction factor is used to adjust the bypass demand, determined based on the equivalent degree of frosting, according to the compressor's current discharge status. For example, when the compressor's discharge status is unsuitable for further increasing the bypass refrigerant flow, the target opening of the proportional bypass valve can be reduced using the discharge parameter correction factor to avoid excessive bypass refrigerant flow that could adversely affect the stable operation of the heat pump system.

[0073] Furthermore, the product of the preset basic bypass opening, ratio, and exhaust parameter correction factor is determined as the target opening of the proportional bypass valve. For example, the target opening can be expressed as: K bypass [i]=K base ×(F i / F critical )×η(P dis, T dis) ; Among them, K bypass [i] represents the target opening degree of the proportional bypass valve corresponding to the current defrost heat exchange section, K base F represents the preset basic bypass opening. i F indicates the equivalent degree of frost formation in the current defrosting heat exchange section. critical Indicates the preset critical frosting threshold, η(P) dis, T dis) This indicates that based on the exhaust pressure Pdis and exhaust temperature T dis Determined exhaust parameter correction factors. The mapping relationship between exhaust parameter correction factors and exhaust pressure and exhaust temperature can be obtained from a preset mapping table.

[0074] Using the above method, the higher the equivalent frosting degree of the current defrosting heat exchange section, the larger the overall target opening of the corresponding proportional bypass valve, allowing more bypass refrigerant to enter the current defrosting heat exchange section. At the same time, the target opening is further corrected by the exhaust parameter correction factor, so that the bypass refrigerant flow not only matches the defrosting demand of the current defrosting heat exchange section, but also adapts to the current actual exhaust state of the compressor.

[0075] Finally, the bypass valve is controlled according to the target opening degree to adjust the bypass refrigerant flow rate entering the current defrost heat exchange section.

[0076] In this embodiment, by using the equivalent frosting degree of the current defrosting heat exchange section, the preset critical frosting degree threshold, and the compressor exhaust state together to determine the opening of the proportional bypass valve, the problem of mismatch between the bypass refrigerant supply and the actual defrosting demand that exists when using a fixed bypass ratio can be avoided. This also provides a basis for dynamically updating the target opening of the proportional bypass valve according to changes in indoor load, compressor operating frequency, and equivalent frosting degree.

[0077] In an optional embodiment, the bypass refrigerant flow rate is corrected based on the exhaust parameters obtained after adjusting the operating frequency (S253), including: The system acquires the exhaust pressure and temperature after frequency adjustment and updates the exhaust parameter correction factor based on these values. It also acquires the equivalent frosting degree of the current defrosting heat exchange section and updates the ratio between the equivalent frosting degree and the preset critical frosting degree threshold. Based on the preset basic bypass opening, the updated ratio, and the updated exhaust parameter correction factor, the system updates the target opening of the proportional bypass valve. Finally, it controls the proportional bypass valve according to the updated target opening to correct the bypass refrigerant flow rate.

[0078] First, after adjusting the compressor's operating frequency according to the indoor load parameters, the compressor's discharge pressure and discharge temperature are reacquired, and the discharge parameter correction factor is updated based on the reacquired discharge pressure and discharge temperature.

[0079] Specifically, when the compressor's operating frequency changes, the compressor's discharge flow rate and discharge status will change accordingly. The discharge parameter correction factor previously used to determine the target opening of the proportional bypass valve may no longer be applicable to the current operating conditions. Therefore, by re-acquiring the discharge pressure and temperature after frequency adjustment, the discharge parameter correction factor is updated so that it can reflect the compressor's current actual discharge status.

[0080] Furthermore, the equivalent degree of frost in the current defrosting heat exchange section is reacquired, and the ratio between the equivalent degree of frost and the preset critical frost degree threshold is updated.

[0081] As the frost state of the current defrosting heat exchange section changes during the continuous defrosting process, the equivalent frost level used to characterize the current defrosting demand also changes accordingly. By re-obtaining the current equivalent frost level and comparing it with a preset critical frost level threshold, an updated ratio reflecting the current defrosting demand can be obtained.

[0082] Furthermore, based on the preset basic bypass opening, the updated ratio, and the updated exhaust parameter correction factor, the target opening of the proportional bypass valve is redefined.

[0083] In other words, the target opening of the proportional bypass valve is not fixed after it is determined when defrosting the current heat exchange section begins, but can be dynamically updated as the equivalent frosting degree of the current defrosting heat exchange section and the compressor discharge state change. This allows the opening of the proportional bypass valve to simultaneously adapt to the real-time changing defrosting requirements of the current defrosting heat exchange section and the current operating conditions of the compressor.

[0084] Finally, the bypass valve is controlled according to the updated target opening to correct the bypass refrigerant flow rate entering the current defrost heat exchange section.

[0085] In this embodiment, after the compressor operating frequency is adjusted due to changes in indoor load, the changes in exhaust state caused by the adjustment of operating frequency can be further fed back to the bypass refrigerant flow control process. At the same time, combined with the changes in the equivalent degree of frost formation in the defrosting heat exchange section during the defrosting process, the target opening of the proportional bypass valve is dynamically corrected, so that the bypass refrigerant flow rate is matched with the current defrosting demand and the real-time operating status of the compressor.

[0086] In an optional embodiment, the compressor parameters also include suction temperature; Adjust the airflow of each heat exchange section (S252) based on the bypass refrigerant flow rate, exhaust parameters, compressor power, and total fan power, including: The equivalent defrosting evaluation index is determined based on the bypass refrigerant flow rate and the temperature difference between the exhaust temperature and the intake temperature; the defrosting energy efficiency factor is determined based on the equivalent defrosting evaluation index, the compressor power, and the total fan power; and the air volume of the current defrosting heat exchange section is adjusted according to the changing trend of the defrosting energy efficiency factor.

[0087] First, the equivalent defrosting evaluation index is determined based on the bypass refrigerant flow rate and the temperature difference between the exhaust and suction temperatures. The equivalent defrosting evaluation index characterizes the defrosting effect under the current bypass refrigerant supply conditions. The bypass refrigerant flow rate reflects the amount of refrigerant supplied to the current defrosting heat exchange section, and the temperature difference between the exhaust and suction temperatures reflects the degree of temperature change of the refrigerant under the current operating conditions. Combining these two factors forms an equivalent evaluation of the current defrosting capability.

[0088] In one implementation, the equivalent defrosting evaluation index can be determined based on the product of bypass refrigerant flow rate and temperature difference. That is, the larger the bypass refrigerant flow rate and the greater the temperature difference between the exhaust and intake temperatures, the larger the overall equivalent defrosting evaluation index. It should be noted that the equivalent defrosting evaluation index is used to evaluate the relative defrosting effect under different control conditions and is not limited to the actual defrosting heat.

[0089] Furthermore, based on the equivalent defrosting evaluation index and the power of the compressor and the total power of the fan, the defrosting energy efficiency factor is determined. The defrosting energy efficiency factor is used to characterize the equivalent defrosting effect obtained under the current operating energy consumption, thereby enabling a comprehensive evaluation of the defrosting performance and operating energy consumption corresponding to the current airflow combination.

[0090] In one implementation, the defrosting efficiency factor can be expressed as: DEF=Q melt / (P comp +P total ); Where DEF represents the defrosting efficiency factor, and Q... melt P represents the equivalent defrosting evaluation index. comp P represents the power of the compressor. total This represents the sum of the power of the fans corresponding to each heat exchange section, i.e., the total power of the fans. Therefore, when the operating power required to achieve the same or higher equivalent defrosting effect is small, the defrosting efficiency factor is relatively high; conversely, the defrosting efficiency factor is relatively low.

[0091] Furthermore, the airflow in the current defrost heat exchange section is adjusted according to the changing trend of the defrost efficiency factor, including: Based on the defrost efficiency factor corresponding to the continuous control cycle, determine the trend of the defrost efficiency factor; when the defrost efficiency factor is on an upward trend, maintain the current airflow of the current defrost heat exchange section; when the defrost efficiency factor is on a downward trend, adjust the current defrost heat exchange section and selectively adjust at least and / or the airflow of non-current defrost heat exchange sections; after adjusting the airflow, reacquire the bypass refrigerant flow rate, exhaust temperature, intake temperature, compressor power, and total fan power, and redetermine the defrost efficiency factor; compare the redetermined defrost efficiency factor with the defrost efficiency factor before airflow adjustment, and continue to adjust or maintain the airflow of each heat exchange section based on the comparison results.

[0092] During defrosting, the controller continuously acquires the defrost efficiency factor (FEF) and determines, based on its trend, whether the current airflow configuration of each heat exchange section is conducive to improving the match between defrosting effect and operating energy consumption. When the FEF shows a downward trend, the airflow of the current defrost heat exchange section and / or non-current defrost heat exchange sections can be further adjusted. After the airflow adjustment, the FEF is re-determined, and airflow adjustment continues based on the re-determined FEF, thereby achieving feedback optimization of the airflow in each heat exchange section.

[0093] In this embodiment, the air volume adjustment no longer relies solely on preset high or low speeds or fixed air volume. Instead, it combines the equivalent defrosting effect represented by the bypass refrigerant with the operating power consumption of the compressor and fan to dynamically adjust the air volume of each heat exchange section. This reduces unnecessary operating energy consumption while meeting the defrosting requirements of the current heat exchange section.

[0094] In an optional embodiment, the compressor parameters further include suction temperature and suction pressure, and the main circuit further includes an electronic expansion valve; the segmented heat pump defrosting control method further includes: The compressor's suction superheat is determined based on the suction temperature and suction pressure. When the suction superheat is lower than the preset safety threshold, the bypass refrigerant flow rate entering the current defrost heat exchange section is reduced, and the opening of the electronic expansion valve is adjusted according to the suction superheat to restore the suction superheat to the preset safety range.

[0095] Specifically, the compressor's suction superheat is determined based on the compressor's suction temperature and suction pressure. Specifically, the saturation temperature of the corresponding refrigerant at the suction pressure can be determined, and the suction superheat is determined based on the difference between the suction temperature and the saturation temperature. SH=T suc -T sat (P suc ); Where SH represents the intake superheat, T suc P represents the compressor's suction temperature. suc T represents the compressor's suction pressure. sat (P suc ) indicates the relationship with inspiratory pressure P suc The corresponding refrigerant saturation temperature.

[0096] During segmented defrosting, some of the high-temperature refrigerant discharged from the compressor enters the current defrosting heat exchange section through the bypass diversion circuit for defrosting, and then returns to the refrigerant circulation circuit after heat exchange. Therefore, changes in the bypass refrigerant flow rate will affect the compressor's suction state. By continuously monitoring the suction superheat, it can be determined whether the current suction state is within the preset safe range.

[0097] When the suction superheat is lower than the preset safety threshold, it indicates that there is a risk of insufficient superheat on the compressor suction side. At this time, the controller reduces the bypass refrigerant flow into the current defrost heat exchange section to reduce the impact of the bypass defrost process on the compressor suction state; at the same time, it adjusts the opening of the electronic expansion valve in the main circuit according to the current suction superheat to change the refrigerant supply state in the main circuit, so that the compressor suction superheat gradually recovers to the preset safety range.

[0098] After completing the above adjustments, the compressor's suction temperature and suction pressure can be obtained again and the suction superheat can be re-determined. Based on the re-determined suction superheat, it can be determined whether it is necessary to continue adjusting the bypass refrigerant flow and / or the opening of the electronic expansion valve, so that the compressor can remain in a safe suction operation state during the segmented defrosting process.

[0099] This embodiment allows for coordinated control of the bypass refrigerant flow and the main circuit refrigerant supply while using the compressor exhaust refrigerant for bypass defrosting. This reduces the risk of liquid return or liquid slugging caused by excessively low suction superheat, and improves the safety and stability of compressor operation during segmented defrosting.

[0100] In an optional embodiment, the indoor load parameters include the actual indoor heating temperature and the corresponding target heating temperature. The actual heating temperature can be the actual water supply temperature or the actual air supply temperature, and the target heating temperature can be the target water supply temperature or the target air supply temperature.

[0101] Adjusting the compressor's operating frequency based on indoor load parameters can include: obtaining the temperature deviation between the actual heating temperature and the target heating temperature, and adjusting the compressor's operating frequency through closed-loop control based on the temperature deviation.

[0102] For example, the temperature deviation can be determined according to the following formula: e=T target -T supply ; Where e represents the temperature deviation, T target T represents the target water supply temperature or target air supply temperature. supply This indicates the actual water supply temperature or the actual air supply temperature.

[0103] The controller can input the temperature deviation into the PI controller, which will then determine the adjustment amount of the compressor's operating frequency based on the temperature deviation and output the corresponding operating frequency command.

[0104] When e > 0, it indicates that the actual heating temperature is lower than the target heating temperature, and the current indoor heating capacity is insufficient. In this case, the compressor operating frequency is increased to improve the heating capacity of the heat pump system. When e < 0, it indicates that the actual heating temperature is higher than the target heating temperature, and the current indoor heating capacity is relatively excessive. In this case, the compressor operating frequency is reduced. When e = 0, it indicates that the actual heating temperature is the same as the target heating temperature, and the current compressor operating frequency can be maintained.

[0105] When the compressor's operating frequency changes, the heat pump system's heating capacity changes accordingly, causing the actual heating temperature to adjust towards the target heating temperature, thus gradually reducing the temperature deviation. The controller can continuously acquire the actual heating temperature and update the temperature deviation, thereby forming a closed-loop negative feedback control based on the indoor heating temperature, ensuring that the indoor heating status remains near the target range during defrosting.

[0106] To further illustrate the implementation process and technical effects of the segmented heat pump defrosting control method of the present invention, a household dual-supply air source heat pump is used as an example.

[0107] In this embodiment, the heat pump system uses a DC inverter scroll compressor with a rated frequency of 50Hz and an operating frequency range of 20-120Hz; the outdoor heat exchanger includes three heat exchange sections A, B, and C, each with a corresponding segmented control valve; the bypass circuit is equipped with a proportional bypass valve, which is an electronic expansion valve driven by a stepper motor; the indoor side uses a water-refrigerant plate heat exchanger, with a target water supply temperature set at 45℃; and the controller is an MCU controller.

[0108] The operating conditions of this embodiment are: ambient temperature 2℃, relative humidity 78%, compressor initial operating frequency 60Hz, and indoor water supply temperature stable at 44.5℃.

[0109] The specific execution process is as follows: S1. Data Acquisition. The controller continuously collects multi-source operating parameters of the heat pump system. These parameters include: ambient temperature of 2℃, relative humidity of 78%, fan power of 185W, coil temperatures of heat exchange sections A, B, and C of 1.2℃, 0.8℃, and -0.3℃, with corresponding coil temperature change slopes of -0.08℃ / min, -0.12℃ / min, and -0.21℃ / min, respectively; compressor operating frequency of 60Hz, discharge pressure of 2.4MPa, discharge temperature of 82℃, indoor supply water temperature of 44.5℃, and return water temperature of 41.0℃.

[0110] S2. Frost Prediction. The collected multi-source operating parameters are input into the frost prediction model to obtain the estimated remaining time before the outdoor heat exchanger reaches the preset critical frost state. The preset lead time is set to 10 minutes. The initial prediction does not yet meet the early defrost trigger condition, so monitoring continues. A second prediction is made after 3 minutes. When the estimated remaining time meets the early defrost trigger condition, this round of defrosting is triggered.

[0111] S3. Segmented Defrosting. The defrosting sequence is determined based on the temperature change slope of the coils in the three heat exchange sections. Sections C, B, and A correspond to -0.21℃ / min, -0.12℃ / min, and -0.08℃ / min respectively, so section C is defrosted first. The proportional bypass valve is adjusted to 25% opening, the segmented control valve corresponding to section C is opened, and the segmented control valves corresponding to sections A and B are closed. Throughout the defrosting process, the four-way valve remains in the heating position.

[0112] S4. Coordinated Adjustment. During the defrosting process of section C, the fan speed corresponding to section C is reduced from 2200 r / min during normal operation to 1000 r / min, while the fans corresponding to sections A and B are maintained at 2200 r / min. According to the indoor heating status, the compressor operating frequency is adjusted from 60 Hz to 65 Hz. At the same time, the main circuit electronic expansion valve is adjusted so that its opening is adjusted from 320 steps to 305 steps to maintain the suction superheat within the range of 5 ± 1℃.

[0113] S5. Heat exchange section switching. After 145 seconds of defrosting in section C, the coil temperature rises to 12℃, and the coil temperature change slope reaches +0.6℃ / min and remains for more than 2 minutes, indicating that section C has completed defrosting. Subsequently, the corresponding section control valve for section C is closed, and the corresponding section defrosting process is performed sequentially for sections B and A.

[0114] S6. Defrosting Completion and Recovery. After each heat exchange section completes its defrosting cycle, the proportional bypass valve opening is gradually reduced from 25% to 0 within 45 seconds. The corresponding fan speed for each heat exchange section is restored to 2200 r / min, and the compressor operating frequency is restored to 60 Hz. During the entire defrosting process, the lowest indoor water supply temperature was 43.8℃, a decrease of 0.7℃ compared to the pre-defrosting water supply temperature of 44.5℃.

[0115] Through the above control process, segmented defrosting of each heat exchange section can be completed while the four-way valve remains in the heating position, avoiding heating interruptions caused by traditional reverse circulation defrosting. Simultaneously, by coordinating the bypass refrigerant flow rate, the air volume of each heat exchange section, and the compressor operating frequency, the defrosting process balances defrosting needs with indoor heating needs. In this embodiment, the indoor water supply temperature only dropped from 44.5℃ to a minimum of 43.8℃ during defrosting, a temperature drop of approximately 0.7℃. This demonstrates that the method can effectively reduce indoor heating fluctuations while completing defrosting, and improve the continuity and operational stability of the defrosting process.

[0116] It should be noted that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0117] Reference Figure 1 The diagram illustrates a heat pump system according to an embodiment of the present invention, specifically including a controller, a main circuit, a bypass circuit, and an outdoor heat exchanger with multiple heat exchange sections connected in parallel. The main circuit includes a compressor and a four-way valve. The air volume of each heat exchange section can be independently adjusted. The bypass circuit is used to selectively deliver a portion of the refrigerant discharged from the compressor to each heat exchange section. The controller is configured to execute the segmented heat pump defrosting control method as described in any embodiment of the present invention.

[0118] The present invention provides a heat pump system that can realize the steps in the aforementioned segmented heat pump defrosting control method embodiments.

[0119] It should be noted that the module division in the various segmented heat pump defrosting control devices provided in the above embodiments is illustrative and only represents a logical functional division. In actual implementation, other division methods may also be used. Furthermore, the functional modules in the various embodiments of this invention can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0120] If the integrated module is implemented as a software functional module 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 technical solution of the embodiments of the present invention can be embodied in the form of a computer program product, which is stored in a computer storage medium and includes several instructions to cause an electronic device or processor to execute all or part of the steps of the methods in the various embodiments of the present invention. The aforementioned computer storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0121] Furthermore, the heat pump system provided in the above embodiments and the segmented heat pump defrosting control method embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0122] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A segmented heat pump defrosting control method, characterized in that, The method is applied to a heat pump system, which includes a main circuit, a bypass circuit, and an outdoor heat exchanger with multiple parallel heat exchange sections. The main circuit includes a compressor and a four-way valve. The airflow of each heat exchange section can be independently adjusted. The bypass circuit is used to selectively deliver a portion of the refrigerant discharged from the compressor to each heat exchange section. The multi-source operating parameters of the heat pump system are obtained. The multi-source operating parameters include at least outdoor environmental parameters, compressor parameters, indoor load parameters, and coil temperature and air volume parameters of each heat exchange section. The compressor parameters include the operating frequency and exhaust parameters of the compressor. Based on the multi-source operating parameters, determine the estimated remaining time for the outdoor heat exchanger to reach the preset critical frosting state; When the estimated remaining time is less than the preset advance amount, the current defrosting cycle is triggered, and the four-way valve is kept in the heating position during the current defrosting cycle. Each heat exchange section is designated as the current defrost heat exchange section, and a portion of the refrigerant discharged from the compressor is selectively delivered to the current defrost heat exchange section via the bypass diversion circuit. During the defrosting process of the current defrosting heat exchange section, the bypass refrigerant flow rate entering the current defrosting heat exchange section, the air volume of the current defrosting heat exchange section, and the operating frequency of the compressor are coordinated and adjusted according to the coil temperature parameters of the current defrosting heat exchange section, the indoor load parameters, and the exhaust parameters. After the current defrosting heat exchange section meets the defrosting completion conditions, the other heat exchange section that has not yet completed this round of defrosting is designated as the new current defrosting heat exchange section and defrosting is performed until all heat exchange sections have completed this round of defrosting.

2. The method according to claim 1, characterized in that, The coil temperature parameters include coil temperature variation parameters; The step of designating each heat exchange section as the current defrosting heat exchange section includes: Based on the coil temperature change parameters of each heat exchange section, the defrosting priority of each heat exchange section is determined; wherein, the coil temperature change parameters include the coil temperature change slope, and the defrosting priority is positively correlated with the absolute value of the coil temperature change slope. According to the defrosting priority, each heat exchange section is determined as the current defrosting heat exchange section.

3. The method according to claim 1, characterized in that, The exhaust parameters include exhaust pressure and exhaust temperature; The step of coordinating the adjustment of the bypass refrigerant flow rate entering the current defrost heat exchange section, the air volume of the current defrost heat exchange section, and the operating frequency of the compressor based on the coil temperature parameters of the current defrost heat exchange section, the indoor load parameters, and the exhaust parameters includes: Based on the coil temperature parameters of the current defrost heat exchange section, determine the equivalent degree of frost formation in the current defrost heat exchange section, and based on the equivalent degree of frost formation and the exhaust parameters, determine the bypass refrigerant flow rate entering the current defrost heat exchange section. Obtain the power of the compressor and the total power of the fan, wherein the total power of the fan is the sum of the power of the fans corresponding to each heat exchange section; The air volume of the current defrost heat exchange section is adjusted according to the bypass refrigerant flow rate, the exhaust parameters, the compressor power, and the total fan power. The operating frequency of the compressor is adjusted according to the indoor load parameters, and the bypass refrigerant flow rate is corrected according to the exhaust parameters obtained after adjusting the operating frequency.

4. The method according to claim 3, characterized in that, The coil temperature parameters include coil temperature change parameters, and the coil temperature change parameters include the coil temperature change slope. The step of determining the equivalent degree of frost formation in the current defrost heat exchange section based on the coil temperature parameters of the current defrost heat exchange section includes: Based on the slope of the coil temperature change and the preset mapping relationship, the equivalent frost degree change rate of the current defrosting heat exchange section is determined; Using the equivalent degree of frost that was present when the current defrosting heat exchange section was last defrosted as the initial value, the change rate of the equivalent degree of frost is integrated over time to obtain the equivalent degree of frost in the current defrosting heat exchange section.

5. The method according to claim 3, characterized in that, The bypass shunt circuit includes a proportional bypass valve; The step of determining the bypass refrigerant flow rate entering the current defrost heat exchange section based on the equivalent frosting degree and the exhaust parameters includes: Obtain the preset critical frosting level threshold and the preset basic bypass opening; Determine the ratio between the equivalent degree of frost and the preset critical frost degree threshold; The exhaust parameter correction factor is determined based on the exhaust pressure and the exhaust temperature. The product of the preset basic bypass opening, the ratio, and the exhaust parameter correction factor is determined as the target opening of the proportional bypass valve; The proportional bypass valve is controlled according to the target opening degree to regulate the bypass refrigerant flow rate entering the current defrost heat exchange section.

6. The method according to claim 5, characterized in that, The step of correcting the bypass refrigerant flow rate based on the exhaust parameters obtained after adjusting the operating frequency includes: The exhaust pressure and exhaust temperature after the operating frequency is adjusted are obtained, and the exhaust parameter correction factor is updated according to the exhaust pressure and exhaust temperature. Obtain the equivalent degree of frost in the current defrosting heat exchange section, and update the ratio between the equivalent degree of frost and the preset critical frost degree threshold. The target opening of the proportional bypass valve is updated based on the preset basic bypass opening, the updated ratio, and the updated exhaust parameter correction factor. The proportional bypass valve is controlled according to the updated target opening to correct the bypass refrigerant flow rate.

7. The method according to claim 3, characterized in that, The compressor parameters also include suction temperature; The step of adjusting the airflow of the current defrost heat exchange section based on the bypass refrigerant flow rate, the exhaust parameters, the compressor power, and the total fan power includes: The equivalent defrosting evaluation index is determined based on the bypass refrigerant flow rate and the temperature difference between the exhaust temperature and the intake temperature. The defrosting energy efficiency factor is determined based on the equivalent defrosting evaluation index, the power of the compressor, and the total power of the fan. Adjust the airflow of the current defrost heat exchange section according to the changing trend of the defrost efficiency factor.

8. The method according to claim 7, characterized in that, The step of adjusting the airflow of the current defrost heat exchange section according to the changing trend of the defrost energy efficiency factor includes: Based on the defrosting energy efficiency factor corresponding to the continuous control cycle, determine the changing trend of the defrosting energy efficiency factor; When the defrost efficiency factor is on an upward trend, maintain the current airflow of the current defrost heat exchange section; When the defrost efficiency factor shows a downward trend, adjust the current defrost heat exchange section and selectively adjust the air volume of at least and / or non-current defrost heat exchange sections; After adjusting the air volume, the bypass refrigerant flow rate, the exhaust temperature, the intake temperature, the power of the compressor, and the total power of the fan are obtained again, and the defrost efficiency factor is re-determined. The redefined defrost efficiency factor is compared with the defrost efficiency factor before airflow adjustment, and the airflow of each heat exchange section is adjusted or maintained based on the comparison result.

9. The method according to claim 1, characterized in that, The compressor parameters also include suction temperature and suction pressure, and the main circuit also includes an electronic expansion valve; The method further includes: The intake superheat of the compressor is determined based on the intake temperature and the intake pressure. When the intake superheat is lower than a preset safety threshold, the bypass refrigerant flow rate entering the current defrost heat exchange section is reduced, and the opening of the electronic expansion valve is adjusted according to the intake superheat to restore the intake superheat to the preset safety range.

10. A heat pump system comprising a controller, a main circuit, a bypass circuit, and an outdoor heat exchanger having multiple heat exchange sections arranged in parallel, the main circuit comprising a compressor and a four-way valve, the airflow of each heat exchange section being independently adjustable, the bypass circuit being used to selectively deliver a portion of the refrigerant discharged by the compressor to each of the heat exchange sections, and the controller being configured to perform a segmented heat pump defrosting control method as described in any one of claims 1-9.

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