An integrated heat pump water heater and a variable frequency control interaction method thereof

Abstract

The application provides a whole heat pump water heater and a variable frequency control interaction method thereof, and relates to the technical field of water heaters.The application constructs an intelligent heat pump system by integrating a variable frequency compressor, a direct current fan, a four-way valve, an electric heater, a water tank, an electronic expansion valve and a controller.The controller communicates with a wire control end and a mobile end, supports user setting strategy parameters, checks running data, and opens bottom layer parameter modification after permission verification, taking into account ease of use and engineering adjustability.During heating, the controller queries a two-dimensional frequency control table according to the ambient temperature, the upper water temperature and a preset strategy, dynamically adjusts the compressor frequency and the fan speed;at the same time, the superheat is calculated based on the return air temperature and the outdoor coil temperature, and the opening degree of the electronic expansion valve is real-time regulated and controlled through PID logic, realizing efficient energy saving, constant temperature stability, rapid response of hot water supply, and significantly improving energy efficiency, control accuracy and user experience.

Description

Technical Field

[0001] This application relates to the field of water heater technology, and in particular to an integrated heat pump water heater and its frequency conversion control interaction method. Background Technology

[0002] As people's living standards improve, the requirements for hot water equipment in terms of comfort, energy efficiency, and safety are increasing. Existing integrated air source heat pump water heaters can efficiently extract heat from the air to heat the water tank, and also have the functions of kitchen cooling and local dehumidification. However, there are still many shortcomings in practical applications: First, most products use fixed frequency control or simple variable frequency strategies, which cannot dynamically optimize the frequency of the variable frequency compressor and the speed of the fan according to the ambient temperature and water temperature, resulting in low energy efficiency and large water temperature fluctuations; Second, the defrosting process usually requires the machine to be shut down, causing the hot water supply to be interrupted and affecting the continuity of use; Third, the user interaction method is simple, and the remote control and engineering-level debugging functions are separated. Ordinary users cannot easily set advanced strategies, and engineers also find it difficult to quickly calibrate control parameters on-site to achieve closed-loop optimization. Summary of the Invention

[0003] This application provides an integrated heat pump water heater and its variable frequency control interaction method to solve one or more technical problems existing in the prior art, and at least provides a beneficial option or creates conditions that enable dynamic adjustment of the variable frequency compressor frequency and fan speed according to environmental conditions and user needs, thereby improving energy efficiency and supporting non-stop defrosting while ensuring constant temperature water supply. Furthermore, it balances convenient operation for ordinary users and precise debugging for engineers by opening up underlying parameter configuration and multi-level interactive interfaces.

[0004] On the one hand, this application provides an integrated heat pump water heater, including: a variable frequency compressor, a DC fan, a four-way valve, an electric heater, a water tank, an electronic expansion valve, and a controller; The water tank is equipped with a first temperature sensor for detecting the upper water temperature and a second temperature sensor for detecting the lower water temperature. The controller establishes a communication connection with the drive-by-wire interaction unit and the mobile application; the drive-by-wire interaction unit and the mobile application provide an interactive interface for receiving frequency conversion control strategy parameters input by the user, transmitting real-time operating data, and granting access to and modification permissions for the underlying operating control parameters after authorization verification. The controller is configured to: In hot water heating mode, based on preset variable frequency control strategy parameters, ambient temperature and upper water temperature, the controller queries the two-dimensional frequency control table stored in the controller to dynamically adjust the operating frequency of the variable frequency compressor and the speed of the DC fan; in the two-dimensional frequency control table, different ambient temperature ranges correspond to frequency-water temperature mapping relationships. The actual superheat is calculated based on the return gas temperature and the outdoor coil temperature, and the opening of the electronic expansion valve is dynamically controlled through PID control logic.

[0005] Furthermore, the underlying operating control parameters include non-stop defrosting control parameters; The controller is also configured to perform a non-stop defrosting operation, specifically: When the defrosting conditions are met, the operating frequency of the variable frequency compressor is reduced to the first preset frequency. After a first preset time delay, the DC fan is turned off and the four-way valve is controlled to switch to the defrosting mode. After a second preset time delay, the variable frequency compressor is increased to the second preset frequency to perform defrosting. When the defrosting exit conditions are met, the operating frequency of the variable frequency compressor is reduced to the first preset frequency. After a third preset time, the four-way valve is controlled to return to the heating mode and the DC fan is turned on. After a fourth preset time, the variable frequency compressor is restored to the normal heating operating frequency before defrosting. Wherein, the first preset frequency, the second preset frequency, the first preset time, the second preset time, the third preset time, and the fourth preset time are all the non-stop defrosting control parameters.

[0006] Furthermore, the underlying operation control parameters also include two-dimensional frequency control table configuration parameters; The construction rules for the two-dimensional frequency control table are as follows: When the ambient temperature is below the first environmental threshold, the operating frequency of the variable frequency compressor is fixed at the low-frequency reference value. When the ambient temperature is not lower than the first environmental threshold, the target operating frequency of the variable frequency compressor decreases step by step as the upper water temperature increases. The first environmental threshold, the low-frequency reference value, and the target operating frequencies at each level are all configuration parameters of the two-dimensional frequency control table.

[0007] Furthermore, the underlying operating control parameters also include oil return control parameters; The controller is also configured to perform oil return control, specifically: When the variable frequency compressor runs continuously below the third preset frequency for a fifth preset time, its operating frequency is controlled to be increased to the fourth preset frequency and maintained for a sixth preset time to perform the oil return operation, and then it is restored to the operating frequency before the oil return. The third preset frequency, the fourth preset frequency, the fifth preset time, and the sixth preset time are all oil return control parameters.

[0008] Furthermore, the underlying operating control parameters also include exhaust temperature protection control parameters; The controller is also configured to perform exhaust temperature protection control, specifically: When the discharge temperature of the variable frequency compressor is higher than the first discharge threshold but not higher than the second discharge threshold, the operating frequency of the variable frequency compressor is controlled to reduce the first frequency reduction magnitude. When the discharge temperature of the variable frequency compressor is higher than the second discharge threshold but not higher than the third discharge threshold, the operating frequency of the variable frequency compressor is controlled to decrease by a second frequency reduction magnitude, which is greater than the first frequency reduction magnitude. When the discharge temperature of the variable frequency compressor is higher than the third discharge threshold, the variable frequency compressor is controlled to stop. Wherein, the first exhaust threshold, the second exhaust threshold, the third exhaust threshold, the first frequency reduction amplitude, and the second frequency reduction amplitude are all exhaust temperature protection control parameters.

[0009] Furthermore, the variable frequency control strategy parameters include the electric auxiliary heating start-up ambient temperature threshold and the hysteresis temperature; The controller also performs the following control functions: Electric auxiliary heating coordinated control: When the ambient temperature is lower than the electric auxiliary heating start-up ambient temperature threshold and the upper water temperature is lower than the difference between the set temperature and the hysteresis temperature, it is determined whether the variable frequency compressor is already running at the maximum allowable frequency; if it is already running at the maximum allowable frequency, the electric heater is controlled to be turned on. High-temperature sterilization control: The lower water temperature is heated to a preset sterilization temperature range and maintained for a preset duration at regular intervals each week; Anti-freeze protection control: In standby mode, the corresponding level of anti-freeze operation logic is triggered based on the ambient temperature and water tank temperature.

[0010] On the other hand, this application provides a variable frequency control interaction method for an integrated heat pump water heater, applied to the aforementioned integrated heat pump water heater, including the following steps: The main interface for the variable frequency control interaction of the integrated heat pump water heater is displayed. The main interface includes variable frequency strategy configuration controls, operation monitoring controls, and engineering diagnostic service controls. In response to the trigger command of the frequency conversion strategy configuration control, the frequency conversion strategy configuration sub-interface is displayed to receive the frequency conversion control strategy parameters set by the user. Based on the variable frequency control strategy parameters, ambient temperature, and upper water temperature, a matching two-dimensional frequency control table is queried to dynamically adjust the operating frequency of the variable frequency compressor and the speed of the DC fan. In the two-dimensional frequency control table, different ambient temperature ranges correspond to frequency-water temperature mapping relationships. At the same time, based on the return air temperature and outdoor coil temperature, the actual superheat is calculated, and the opening of the electronic expansion valve is dynamically controlled through PID control logic. In response to the trigger command of the operation monitoring control, the operation monitoring sub-interface is displayed, and the operation data is transmitted back and visualized in real time. The operation data includes the frequency of the variable frequency compressor, the water temperature change trend, and the defrost event log. In response to the trigger command of the engineering diagnostic service control, after the permission verification is passed, the engineering diagnostic service sub-interface is displayed, granting access to and modification permissions for the underlying operation control parameters, so as to calibrate or correct the control strategy and form a closed-loop optimization.

[0011] Furthermore, the variable frequency control strategy parameters include target water temperature, operating mode, electric auxiliary heating start-up ambient temperature threshold, and hysteresis temperature; Perform the following operations in the frequency conversion strategy configuration sub-interface: Receive the target water temperature set by the user and generate the start / stop threshold range according to the preset hysteresis logic; The system receives the user-selected operating mode, which includes standard mode, hybrid mode, and electric heating mode. The standard mode relies on a heat pump system to absorb heat from the air to heat the water in the tank; the hybrid mode combines the heat pump and electric heating working together; the electric heating mode is used to control the electric heater to start for auxiliary heating based on the electric auxiliary heating start-up ambient temperature threshold and hysteresis temperature. The set frequency converter control strategy parameters are packaged into a control strategy package and sent to the controller to load and execute the corresponding frequency converter control logic.

[0012] Furthermore, the operation monitoring sub-interface includes a real-time status display area, an energy efficiency trend area, a defrost event recording area, and an abnormal alarm push area; The display logic of the operation monitoring sub-interface is as follows: The real-time status display area dynamically refreshes the ambient temperature, upper water temperature, current operating frequency of the variable frequency compressor, DC fan speed, four-way valve status, and electric heater start / stop status. Based on historical operating data, the frequency-water temperature change curve of the variable frequency compressor is plotted through the energy efficiency trend area, and an ambient temperature time series graph is superimposed to visualize the synergistic effect of variable frequency control on energy efficiency and water output stability. The defrost event recording area lists the start and end times, duration, water temperature difference before and after defrost, and frequency change of the variable frequency compressor for each defrost event, and highlights the water temperature fluctuation range during non-stop defrosting. The abnormal alarm push area automatically pushes alarm information when exhaust temperature exceeds the limit, oil return is abnormal, or communication is interrupted, and supports clicking to display a snapshot of the operating parameters for the corresponding time period.

[0013] Furthermore, the underlying operating control parameters include: two-dimensional frequency control table configuration parameters, non-stop defrosting control parameters, oil return control parameters, and exhaust temperature protection control parameters; The engineering diagnostic service sub-interface includes a permission verification control, a low-level parameter monitoring control, a control logic debugging control, and a strategy table editing control. The operation logic of the engineering diagnostic service sub-interface is as follows: In response to the trigger command of the permission verification control, an identity authentication window is displayed, the verification information input by the engineer is received, and the engineering mode function permission is unlocked after the verification is successful. In response to the trigger command of the underlying parameter monitoring control, a real-time parameter monitoring window is displayed, continuously transmitting and displaying the variable frequency compressor discharge temperature, outdoor coil temperature, electronic expansion valve opening, superheat, and DC bus voltage. In response to the trigger command of the control logic debugging control, the debugging operation panel is displayed, providing a forced oil return test button and a manual defrost trigger button for performing oil return or defrost debugging operations; In response to the trigger command of the strategy table editing control, the control strategy editing window is displayed, allowing the underlying operating control parameters to be calibrated, corrected or reconfigured, and the updated parameters are written to the controller storage unit to achieve field adaptation and closed-loop optimization of the control strategy.

[0014] The beneficial effects of this application are as follows: This application provides an integrated heat pump water heater, which integrates a variable frequency compressor, a DC fan, a four-way valve, an electric heater, a water tank, an electronic expansion valve, and a controller. Temperature sensors are installed at the top and bottom of the water tank to achieve accurate sensing of water temperature distribution. The controller establishes a communication connection with the wired control interaction unit and the mobile application, which not only allows users to input variable frequency control strategy parameters and view operating data in real time through the interactive interface, but also allows access to and modification of the underlying operating control parameters after authorization verification, taking into account both the convenient operation of ordinary users and the in-depth debugging needs of engineers. In hot water heating mode, the controller, based on the preset variable frequency control strategy parameters, ambient temperature, and upper water temperature, queries the built-in two-dimensional frequency control table to dynamically adjust the operating frequency of the variable frequency compressor and the speed of the DC fan. At the same time, it calculates the actual superheat based on the return air temperature and the outdoor coil temperature, and adjusts the opening of the electronic expansion valve in real time through PID control logic, thereby achieving a highly efficient, energy-saving, constant temperature, and rapid response hot water supply, significantly improving the overall energy efficiency, control accuracy, and user experience. This application also provides a variable frequency control interaction method for integrated heat pump water heaters. The beneficial effects of the variable frequency control interaction method are similar to those of the water heaters mentioned above, and will not be repeated here.

[0015] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0017] Figure 1 This is a structural diagram of the integrated heat pump water heater provided in this application; Figure 2 This is a flowchart of the variable frequency control interaction method for the integrated heat pump water heater provided in this application; Figure 3 This is a schematic diagram of the main interface of the variable frequency control interaction of the integrated heat pump water heater provided in this application; Figure 4 This is a schematic diagram of the operation monitoring sub-interface provided in this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] The present application will be further described below with reference to the accompanying drawings and specific embodiments. The described embodiments should not be considered as limitations on the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0020] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0022] With the global energy structure transformation and the advancement of "dual carbon" goals, high-efficiency, energy-saving, low-carbon, and environmentally friendly heat pump technology has received widespread attention in the field of hot water supply. Integrated heat pump water heaters, as devices that integrate the heat pump unit and the storage tank, are gradually becoming an important development direction for residential and small commercial hot water solutions due to their advantages such as convenient installation, no need for on-site welding of refrigerant pipes, good sealing, high energy efficiency, and potential for waste heat recovery. These products are based on the reverse Carnot cycle principle, absorbing low-grade heat energy from the ambient air, upgrading it to high-grade heat energy by a variable frequency compressor, and then using it to heat the water in the tank. Under the same heating capacity, its energy consumption is far lower than that of traditional electric or gas water heaters. It also features safe operation, no combustion emissions, and the ability to achieve localized cooling and dehumidification in the kitchen, making it a product with excellent comprehensive application value.

[0023] Specifically, a complete integrated air source heat pump water heater consists of two main parts: a cooling unit and a hot water heating unit. These two parts are closely linked and inseparable, and must work simultaneously. That is, it heats the hot water while simultaneously cooling the kitchen, or vice versa.

[0024] Its internal structure mainly consists of four core components: compressor, condenser, expansion valve, and evaporator. Its working process is as follows: The compressor compresses the returning low-pressure refrigerant, turning it into a high-temperature, high-pressure gas, which is then discharged. This high-temperature, high-pressure refrigerant gas flows through copper pipes wrapped around the outside of the water tank. Heat is conducted to the water tank through these pipes. The cooled refrigerant, under continuous pressure, becomes liquid and enters the evaporator after passing through the expansion valve. Due to the sudden drop in pressure in the evaporator, the liquid refrigerant rapidly evaporates into a gas, absorbing a large amount of heat. Simultaneously, driven by a fan, a large amount of air flows over the outer surface of the evaporator. The energy in the air is absorbed by the evaporator, rapidly lowering the air temperature, and the cooled air is discharged into the kitchen. The refrigerant, having absorbed some energy, then flows back to the compressor, entering the next cycle.

[0025] As can be seen from the above working principle, the working principle of an integrated air source water heater is somewhat similar to that of an air conditioner. It applies the reverse Carnot cycle, absorbing a large amount of low-temperature heat energy from the air, compressing it into high-temperature heat energy through a compressor, and transferring it to the water tank to heat the water. The entire process is an energy transfer process (from air to water), not an energy conversion process. It does not use electric heating elements to heat the water, nor does it use combustible gas to heat the water.

[0026] Currently available integrated heat pump water heaters on the market mainly employ fixed-frequency variable-frequency compressors or basic variable-frequency control strategies. Fixed-frequency models can only start and stop at a fixed frequency during operation, leading to large water temperature fluctuations, poor comfort, and additional energy consumption and mechanical wear due to frequent start-stop cycles. While some variable-frequency products introduce frequency adjustment capabilities, their control logic is relatively simple, typically relying on a coarse adjustment based on the temperature at a single location in the water tank or a set temperature difference. This fails to fully consider factors such as ambient temperature changes, internal temperature stratification in the water tank, fan airflow matching, and dynamic system heat load, making it difficult to achieve true on-demand energy supply and optimal energy efficiency. Furthermore, existing products generally rely on a shutdown defrosting mode, where hot water heating is paused and defrosting begins upon detecting frost on the evaporator. This process not only interrupts hot water supply, affecting continuous user experience, but may also lead to over-defrosting or incomplete defrosting due to inaccurate timing, further reducing system efficiency.

[0027] At the system control level, most integrated heat pump water heaters currently have their underlying operating parameters, such as the electronic expansion valve opening control coefficient, the variable frequency compressor exhaust temperature protection threshold, the oil return cycle logic, and the superheat target value, fixed in the controller firmware. Users or after-sales engineers cannot flexibly adjust these parameters according to the actual installation environment (such as high humidity, low temperature, high altitude, etc.) or usage habits. This closed control architecture limits the equipment's adaptability to complex operating conditions and increases the difficulty of debugging and maintenance. Meanwhile, the human-machine interaction is relatively simple, usually equipped with only simple local buttons or LED displays, lacking remote monitoring and intelligent interaction capabilities. Even some high-end models that support Wi-Fi connectivity and mobile app control are mostly limited to basic operations such as power on / off and temperature setting, unable to provide access to advanced data such as variable frequency strategies, operating curves, and fault logs, and lack a parameter access mechanism with hierarchical permissions. This prevents ordinary users from participating in personalized energy-saving settings, and professionals on-site cannot quickly calibrate key control parameters to achieve closed-loop optimization.

[0028] Furthermore, current technologies for sensing water tank temperature generally rely on single-point temperature measurement, which is insufficient to accurately reflect the actual temperature distribution within the tank. Due to natural convection and thermal stratification during the heat pump heating process, the water temperature at the top is often significantly higher than at the bottom. If only the top temperature is used as the control basis, it can easily lead to insufficient bottom water temperature causing premature shutdown, affecting the effective hot water output. Conversely, if the bottom temperature is used as the standard, it may result in overheating at the top, increased energy consumption, or even the risk of dry burning. Therefore, the lack of multi-point temperature collaborative sensing and stratified control strategies has become a key bottleneck restricting the improvement of overall system performance.

[0029] In summary, existing integrated heat pump water heaters still have significant shortcomings in terms of the precision of frequency conversion control, the continuity of defrosting, the configurability of underlying parameters, the level of intelligent human-machine interaction, and the accuracy of water temperature sensing. These shortcomings make it difficult to meet users' comprehensive needs for constant temperature comfort, high efficiency and energy saving, stable reliability, and intelligent convenience. To address these issues, a novel integrated heat pump water heater and its frequency conversion control interaction method are urgently needed. This method involves constructing a multi-sensor fusion sensing system, introducing a dynamic frequency conversion strategy based on the coupling of environment and water temperature, achieving non-stop defrosting support, providing open parameter configuration interfaces under hierarchical permissions, and combining a dual-channel interaction architecture of wired control and mobile terminals. This will comprehensively improve the system's adaptability, operating efficiency, and user experience, providing a feasible path for the high-quality development of heat pump water heating technology.

[0030] To address the aforementioned issues, this application provides an integrated heat pump water heater and its variable frequency control interaction method. By installing temperature sensors at the top and bottom of the water tank, precise sensing of water temperature stratification is achieved. Based on the ambient temperature and the upper water temperature, a two-dimensional frequency control table is dynamically queried to intelligently adjust the frequency of the variable frequency compressor and the speed of the DC fan, thereby achieving on-demand energy supply and efficient operation. Simultaneously, the system introduces calculations of actual superheat based on return gas temperature and outdoor coil temperature, and uses PID logic to adjust the opening of the electronic expansion valve in real time, improving the accuracy of refrigerant flow control. The controller establishes communication connections with the wired control interaction unit and mobile application, supporting user input of variable frequency control strategies and viewing of operating data. After authorization verification, access to and modification of underlying operating parameters are also granted, balancing convenient operation for ordinary users with the in-depth debugging needs of engineers. The overall structure has a high degree of integration, supporting non-stop defrosting, multi-mode switching, and hierarchical interactive control, effectively solving problems such as low energy efficiency, large water temperature fluctuations, closed parameters, limited interaction, and interrupted hot water supply in existing technologies.

[0031] First, the integrated heat pump water heater provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0032] Reference Figure 1 The integrated heat pump water heater provided in this application includes: a variable frequency compressor, a DC fan, a four-way valve, an electric heater, a water tank, an electronic expansion valve, and a controller.

[0033] The variable frequency compressor is the core power component of the heat pump system. It is used to compress the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas, thereby releasing heat to heat the water in the water tank. Its variable frequency characteristics allow the operating frequency to be dynamically adjusted according to the actual heat load demand, so as to achieve energy saving and constant temperature control.

[0034] The water tank is used to store heated hot water. The water tank is equipped with a first temperature sensor for detecting the water temperature at the top and a second temperature sensor for detecting the water temperature at the bottom. These sensors detect the water temperature at different heights to accurately reflect the water temperature stratification and provide a basis for precise control of the heating strategy.

[0035] The outer wall of the water tank is wrapped with condensing coils as a condenser; in addition, the evaporator is set in the ventilation duct inside the shell of the integrated heat pump water heater. It works with a DC fan to absorb heat from the air in the environment where the equipment is located (such as the kitchen). It is the low-temperature heat source heat exchanger of the heat pump cycle. It is independent of the water tank, but forms a closed loop with the condenser in the water tank through the refrigerant pipeline.

[0036] The DC fan is installed on the outdoor heat exchanger side to drive airflow through the evaporator or condenser and promote heat exchange. The DC motor can achieve stepless speed regulation, and the variable frequency compressor can adjust the air volume according to the ambient temperature and system requirements to improve the overall energy efficiency and operational stability of the unit.

[0037] A four-way valve is a control valve that switches the direction of refrigerant flow. When switching between heating mode and defrosting mode, it changes the refrigerant circulation path, enabling the system to flexibly switch between normal heating and evaporator defrosting, and supports advanced functions such as non-stop defrosting.

[0038] The electric heater is installed inside the water tank or in the water flow channel as an auxiliary heat source. It is activated when the ambient temperature is too low, resulting in insufficient heating capacity of the heat pump, or when the user needs to heat up quickly, to ensure the continuity and response speed of hot water supply.

[0039] Optionally, the upper temperature sensor of the water tank is located 100mm from the top cover, and the lower sensor is 150mm from the bottom surface. Both are NTC sensors with an accuracy of ±0.5℃. The ambient temperature sensor is placed inside the fan inlet cavity with a sunshade. The return air and coil temperature sensors are both PT1000 copper-cased sensors with a response time of <5s and a sampling period of 1s.

[0040] The electronic expansion valve is located in the refrigerant circulation loop and controls the refrigerant flow into the evaporator by precisely adjusting its opening degree. Its opening degree is dynamically adjusted by the controller based on the actual superheat and through a PID algorithm to maintain a highly efficient and stable thermodynamic cycle in the system.

[0041] The controller establishes a communication connection with the drive-by-wire interaction unit and the mobile application. The drive-by-wire interaction unit and the mobile application provide an interactive interface for receiving user-inputted frequency converter control strategy parameters, transmitting real-time operating data, and granting access to and modification permissions for underlying operating control parameters after successful authorization verification.

[0042] Specifically, the controller, as the intelligent hub of the whole machine, is responsible for collecting signals from various sensors, executing control logic, driving the execution components, and communicating with the wire-controlled interactive unit and mobile application. It not only realizes the coordinated control of the variable frequency compressor, DC fan and electronic expansion valve, but also supports user-defined control strategies and configuration of underlying operating parameters after authorization verification, comprehensively improving the intelligence level and adaptability of the system.

[0043] In some embodiments of this application, the refrigerant circulation loop logic is as follows: The discharge port of the variable frequency compressor is connected to the condenser (i.e., water-side heat exchanger) inside or on the outer wall of the water tank through a high-temperature, high-pressure gaseous refrigerant pipeline. The refrigerant releases heat here to heat the water in the water tank, and after cooling, it becomes a high-pressure liquid. After the liquid refrigerant flows out of the condenser, it enters the electronic expansion valve, and after throttling and depressurization, it becomes a low-temperature, low-pressure gas-liquid two-phase flow. Then it flows into the evaporator (located on the outdoor side or at the air inlet of the equipment). When the ambient air driven by the DC fan flows through the evaporator fins, the refrigerant absorbs heat from the air and completely evaporates into a low-temperature, low-pressure gas. The gas returns to the suction port of the variable frequency compressor through the return pipe, completing the main refrigerant cycle.

[0044] In some embodiments of this application, a four-way valve serves as a flow direction switching device, with its four ports connected to: the compressor discharge port, the compressor suction port, one side of the condenser (water tank heat exchanger), and one side of the evaporator. In heating mode, the four-way valve causes the refrigerant to flow in the direction of "compressor → condenser → electronic expansion valve → evaporator → compressor"; in defrosting mode, the four-way valve switches the flow path, allowing the high-temperature exhaust gas to directly enter the evaporator for defrosting, thus reversing the flow direction.

[0045] In some embodiments of this application, the electric heater is installed inside the water tank, submerged in water, and in direct thermal contact with the water tank. Its electrical circuit is independently connected to the controller, which can be activated by the controller to provide auxiliary heating when the heat pump heating capacity is insufficient.

[0046] In some embodiments of this application, the controller serves as the intelligent central hub of the entire machine and is connected to the following components via signal lines: acquiring the operating frequency, current, and exhaust temperature of the variable frequency compressor; driving the speed of the DC fan (usually using PWM or 0–10 V analog signals); controlling the on / off state of the solenoid coil of the four-way valve to switch modes; switching the relay or solid-state switch of the electric heater; reading the position feedback of the electronic expansion valve (if any) and outputting the opening adjustment signal (usually a pulse signal); and receiving signals from multiple temperature sensors, such as those at the top / bottom of the water tank, the environment, the return air, and the outdoor coil, for comprehensive judgment and closed-loop control.

[0047] In summary, all components are physically highly integrated within the same housing (integrated structure) and logically coordinated by a unified controller, forming a complete heat pump water heating system with a variable frequency compressor as the main power source, an electronic expansion valve as the core of flow regulation, a four-way valve to support defrosting switching, an electric heater for emergency supplementation, a DC fan to enhance heat exchange, and a water tank as an integrated carrier for heat storage and heat exchange.

[0048] In some embodiments of this application, the controller is configured to perform the following operations: In hot water heating mode, based on preset variable frequency control strategy parameters, ambient temperature, and upper water temperature, the controller queries a two-dimensional frequency control table stored in the controller to dynamically adjust the operating frequency of the variable frequency compressor and the speed of the DC fan. In the two-dimensional frequency control table, different ambient temperature ranges correspond to a frequency-water temperature mapping relationship, and the actual superheat is calculated based on the return air temperature and the outdoor coil temperature. The opening degree of the electronic expansion valve is then dynamically controlled through PID control logic.

[0049] Specifically, in hot water heating mode, the controller queries a two-dimensional frequency control table stored in the controller based on preset variable frequency control strategy parameters, ambient temperature, and upper water temperature. The core function of this operation is to achieve precise dynamic adjustment of the overall unit's operating status. Traditional heat pump water heaters typically operate based on a single water temperature or fixed frequency, making it difficult to balance energy efficiency and comfort under different climatic conditions. This application, however, introduces a two-dimensional frequency control table, dividing the ambient temperature into multiple intervals. Within each interval, a mapping relationship is established between the compressor frequency and the upper water temperature, enabling the controller to accurately select the optimal compressor operating frequency and matching DC fan speed based on the current external environment and the actual thermal state of the upper part of the water tank. For example, in low-temperature environments, the system can automatically increase the frequency to maintain heating capacity; while at high temperatures or when the water temperature is close to the set value, the frequency is reduced to avoid overshoot and energy waste. This multi-dimensional coupled control method significantly improves the overall unit's adaptability, energy efficiency, and outlet water temperature stability.

[0050] Furthermore, the controller calculates the actual superheat based on the return gas temperature and the outdoor coil temperature, and dynamically controls the opening of the electronic expansion valve through PID control logic. This step aims to optimize the thermodynamic performance and operational reliability of the refrigerant circulation system. Superheat is a key parameter for measuring the refrigerant state at the evaporator outlet, directly affecting the compressor oil return effect, system heat exchange efficiency, and safety. If the superheat is too low, liquid refrigerant may flow back to the compressor, causing liquid slugging; if it is too high, it indicates insufficient evaporation, resulting in decreased refrigerant utilization and increased energy consumption. This application accurately calculates the actual superheat under the current operating conditions by real-time acquisition of the return gas temperature and the outdoor coil temperature, compares it with the target superheat, and uses a proportional-integral-derivative (PID) control algorithm to generate adjustment commands and dynamically adjust the opening of the electronic expansion valve. This mechanism ensures that the refrigerant flow rate always matches the heat load demand, maintaining a highly efficient and stable evaporation process under various ambient temperatures and operating stages. This not only improves the overall energy efficiency ratio but also enhances the system's robustness and long-term operational reliability under complex conditions such as low temperature and high humidity.

[0051] In some embodiments of this application, the two-dimensional frequency control table is stored in the controller's Flash memory as a two-dimensional array. The row index is the ambient temperature range (e.g., <–5℃, –5 to 5℃, >5℃), and the column index is the water temperature range (<45℃, 45–50℃, ≥50℃). The controller samples the ambient temperature and the upper water temperature every 2 seconds, locates the corresponding cell using if-else or table lookup instructions, and directly outputs the pre-stored frequency value without real-time calculation, ensuring a response speed of <100ms.

[0052] In some embodiments of this application, an example of a two-dimensional frequency control table is provided: when the ambient temperature is below -5℃, the compressor frequency is forcibly locked at 30Hz; when the ambient temperature is between -5℃ and 5℃, if the water temperature at the top of the tank is <45℃, the frequency is set to 45Hz; when 45℃ ≤ water temperature < 50℃, it drops to 38Hz; and when the water temperature is ≥50℃, it drops to 30Hz. When the ambient temperature is ≥5℃, the frequencies corresponding to the three water temperature ranges are 40Hz, 32Hz, and 25Hz, respectively. The DC fan speed is synchronously linked: 30Hz corresponds to 600RPM, 40Hz corresponds to 900RPM, and 45Hz corresponds to 1100RPM. The controller reads the ambient temperature (from the NTC sensor at the air inlet) and the upper water temperature (NTC sensor 100mm from the top of the tank) every 2 seconds, and directly looks up the target frequency and fan speed from the table based on the range judgment, without interpolation or complex calculations, ensuring fast and stable response.

[0053] In some embodiments of this application, the actual superheat is calculated based on the return gas temperature and the outdoor coil temperature, specifically including: Actual superheat = Compressor return gas temperature – Outdoor evaporator coil temperature. The return gas temperature is measured by a PT1000 sensor installed on the suction pipe, and the coil temperature is taken from another PT1000 sensor on the surface of the copper tube in the middle of the evaporator. For example, if the return gas temperature is measured to be 8°C and the coil temperature to be 5°C under a certain operating condition, then the superheat is 3K. This value directly reflects whether evaporation is sufficient—too low (e.g., <1.5K) poses a risk of liquid slugging, while too high (e.g., >6K) indicates that the refrigerant is not fully utilizing the heat exchange area.

[0054] In some embodiments of this application, taking the scenario of PID-controlled electronic expansion valve as an example: the target superheat is set to 4K, the PID uses an incremental algorithm, the proportional coefficient Kp=0.8, the integral time Ti=120s, and the derivative time Td=15s. The initial opening of the electronic expansion valve is 300 steps (driven by a stepper motor, 0–600 steps in the full stroke). The controller performs a PID calculation every 10s, and the output adjustment is limited to ±5 steps / s to prevent valve body oscillation. Actual measurements show that within an ambient temperature range of -7℃ to 35℃, this strategy can stably control the actual superheat within the range of 3.5–4.5K, avoiding liquid return while ensuring evaporation efficiency.

[0055] In some embodiments of this application, the underlying operating control parameters include non-stop defrosting control parameters. The significance of this design lies in fundamentally solving the technical bottleneck of traditional heat pump water heaters requiring an interruption of hot water supply during defrosting. Conventional defrosting strategies typically require a complete shutdown of the compressor or switching to pure defrosting mode, resulting in users being unable to obtain hot water during this period, severely impacting the user experience. However, by incorporating non-stop defrosting control parameters into a configurable underlying parameter system, the system can complete evaporator defrosting while ensuring continuous heating of the water tank. This maintains the continuity of hot water output and improves the adaptability and reliability of the entire unit in low-temperature and high-humidity environments, providing users with truly stable, all-weather hot water service.

[0056] The controller is also configured to perform a non-stop defrosting operation, with the following specific logic.

[0057] (1) When the defrosting conditions are met, the operating frequency of the variable frequency compressor is reduced to the first preset frequency, the DC fan is turned off after a first preset time and the four-way valve is switched to the defrosting mode, and after a second preset time, the variable frequency compressor is increased to the second preset frequency to perform defrosting.

[0058] Specifically, when the defrosting entry conditions are met, the controller first reduces the operating frequency of the inverter compressor to a first preset frequency. This operation smoothly transitions the system state, preventing pressure surges or sudden drops in water temperature caused by frequency abrupt changes. Then, a first preset time delay is allowed to stabilize the refrigerant pressure and temperature within the system, creating safe conditions for the four-way valve to switch. Next, the DC fan is shut off, and the four-way valve is switched to defrost mode. At this point, the refrigerant flow reverses, and the high-temperature, high-pressure gas directly enters the outdoor evaporator to melt the frost layer. Since the compressor continues to operate at a lower frequency and the water tank already has a certain heat reserve, the water-side heat exchanger can still maintain a weak heating capacity, thus achieving a "non-stop" effect. After a second preset time delay, the inverter compressor is increased to a second preset frequency to perform efficient defrosting, ensuring the defrosting process is completed in the shortest possible time and minimizing the impact on overall heating efficiency. The entire entry logic precisely coordinates the timing of frequency, fan shutdown, and valve switching, balancing defrosting efficiency with hot water continuity.

[0059] (2) When the defrosting exit condition is met, the operating frequency of the variable frequency compressor is reduced to the first preset frequency, and after a third preset time, the four-way valve is controlled to return to the heating mode and the DC fan is turned on. After a fourth preset time, the variable frequency compressor is restored to the normal heating operating frequency before defrosting.

[0060] Specifically, when the defrost exit conditions are met, the controller reduces the operating frequency of the inverter compressor back to the first preset frequency. This buffers the system before resuming heating, preventing refrigerant backflow or compressor overload caused by the instantaneous switching of the four-way valve. A third preset time delay is then allowed to rebalance the pressure in the pipeline, providing a window for the four-way valve to safely reset. Afterward, the four-way valve is controlled to return to heating mode and the DC fan is activated to re-establish the normal air-refrigerant heat exchange path. After a fourth preset time delay, once the system operation has stabilized, the inverter compressor returns to its normal heating operating frequency before defrosting, continuing to efficiently heat the water tank. This exit logic effectively avoids water temperature fluctuations or mechanical stress caused by sudden frequency increases or airflow changes after defrosting, ensuring a smooth return of the system to main heating mode and guaranteeing user comfort and long-term equipment stability.

[0061] Among them, the first preset frequency, the second preset frequency, the first preset time, the second preset time, the third preset time, and the fourth preset time are all used as non-stop defrosting control parameters and are incorporated into the controller's configurable underlying parameter set. This design gives the system a high degree of environmental adaptability and engineering adjustability.

[0062] Climate conditions vary significantly across regions, such as winter humidity, minimum temperature, and frost rate, making it difficult to universally apply fixed defrosting sequences. By granting access permissions to these parameters, professionals can optimize and adjust them based on actual field data after authorization. For example, they can appropriately extend the defrosting operation time in high-humidity areas or reduce the first preset frequency in cold regions to minimize water temperature fluctuations, thereby achieving localized and precise matching of defrosting strategies. This configurable parameter mechanism not only improves product performance in diverse application scenarios but also creates technical conditions for later maintenance, fault diagnosis, and energy efficiency upgrades.

[0063] In some embodiments of this application, the defrosting start condition can be defined as: continuous operation in heating mode for ≥30 minutes, outdoor coil temperature ≤-5℃, ambient temperature ≤7℃, and compressor current fluctuation <5% (indicating that the evaporator has frosted, leading to heat exchange attenuation). The defrosting exit condition is: defrosting operation time ≥4 minutes, or coil temperature ≥12℃, and compressor exhaust temperature steadily rising by more than 5K / min, indicating that the frost layer has basically melted.

[0064] In some embodiments of this application, the first preset frequency is set to 28Hz. This frequency is low enough to reduce system pressure surges while maintaining compressor operation to ensure a slight heat output from the water tank side, preventing hot water interruption. The second preset frequency is set to 48Hz. This is a high-efficiency defrosting frequency; after the four-way valve switches, the compressor power is increased, allowing the high-temperature exhaust gas to quickly heat the evaporator and accelerate defrosting.

[0065] In some embodiments of this application, the first preset time is 15 seconds. This is used to wait for the refrigerant pressure to balance after frequency reduction, preventing liquid slugging during the four-way valve switching. The second preset time is 8 seconds. This ensures the four-way valve is fully engaged before increasing the frequency, avoiding high power loading before the valve body has finished switching. The third preset time is 12 seconds. This reduces the frequency again before exiting defrosting and waits for the system pressure to stabilize, preparing for the four-way valve to switch back to heating mode. The fourth preset time is 20 seconds. After the fan and heating cycle resume, sufficient time is allowed for the refrigerant flow to stabilize and the water temperature to rise before resuming the original operating frequency, preventing a sudden drop in water temperature or compressor overload.

[0066] In some embodiments of this application, assuming the unit operates continuously for 35 minutes at an ambient temperature of 2°C and a water temperature of 42°C at the top of the water tank, the outdoor coil temperature is detected to have dropped to -6°C, and the compressor current tends to stabilize, indicating that the defrosting start conditions are met. The controller first reduces the frequency of the inverter compressor from the current 38Hz to 28Hz, and after a 15-second delay, shuts off the DC fan (speed drops from 900RPM to 0), while simultaneously driving the four-way valve to switch to defrosting mode. After another 8-second delay, the compressor frequency is increased to 48Hz, and high-temperature exhaust gas enters the outdoor heat exchanger to begin defrosting. Four minutes later, the coil temperature rises to 13°C, meeting the exit conditions. The controller immediately reverts the frequency back to 28Hz, and after a 12-second delay, the four-way valve switches back to heating mode and starts the fan at 900RPM. After a 20-second system stabilization period, the compressor frequency returns to the pre-defrosting 38Hz, and normal heating continues. Throughout the entire process, the water tank temperature fluctuation does not exceed ±1.5°C, and the user experiences no interruption.

[0067] In some embodiments of this application, the underlying operating control parameters also include two-dimensional frequency control table configuration parameters, enabling the integrated heat pump water heater to achieve a highly adaptive frequency control strategy based on the dual variables of external ambient temperature and the internal thermal state of the water tank.

[0068] Traditional heat pump systems typically use a single temperature threshold or a fixed frequency curve for adjustment, making it difficult to simultaneously address insufficient heating capacity in low-temperature environments and energy waste in high-temperature environments. However, by introducing a configurable two-dimensional frequency control table, the system establishes a dynamic mapping relationship between ambient temperature and the upper water temperature. This allows the compressor frequency to be optimized in real-time according to actual operating conditions, rather than being a static setting. This maximizes energy efficiency while ensuring a stable hot water supply and provides flexible engineering adaptability for product deployment under different regional climate conditions.

[0069] Furthermore, the construction rules for the two-dimensional frequency control table are as follows.

[0070] (1) When the ambient temperature is below the first environmental threshold, the operating frequency of the variable frequency compressor is fixed at a low-frequency reference value to address system safety and reliability issues under extreme low-temperature conditions. In cold environments, the available thermal energy in the air is significantly reduced. If the compressor frequency is forcibly increased to pursue heating speed, it will not only lead to a sharp drop in energy efficiency, but may also cause risks such as excessively high exhaust temperature, difficulty in oil return, or even compressor overload. Therefore, under this condition, the system actively limits the frequency to a preset low-frequency reference value, which can maintain the basic heating cycle to avoid complete shutdown, and also prevent equipment damage due to overload operation. This strategy reflects the protective control logic for low-temperature extreme conditions, ensuring that the whole machine can still provide a limited but continuous hot water output stably and safely under severe cold conditions.

[0071] (2) When the ambient temperature is not lower than the first environmental threshold, the target operating frequency of the variable frequency compressor gradually decreases as the upper water temperature rises, achieving refined on-demand energy supply and energy-saving operation. In normal or warm environments, the heat pump system has sufficient heat source. If the upper water temperature of the water tank is close to or reaches the user's set target, continuing to operate at a high frequency will result in energy waste and water temperature overshoot. By setting multiple target operating frequencies, the controller can automatically select the corresponding lower frequency according to the range of the upper water temperature, gradually slowing down the heating rate and making the water temperature steadily approach the set value. This gradual frequency reduction strategy effectively suppresses the temperature fluctuations caused by traditional start-stop control, improves the comfort of the water outlet, and significantly reduces the ineffective energy consumption during standby, achieving a balance between high-precision constant temperature and high-efficiency operation.

[0072] The first environmental threshold, low-frequency reference value, and target operating frequencies at each level are all incorporated into the underlying adjustable parameter system as configuration parameters of a two-dimensional frequency control table. This arrangement endows the product with strong on-site adaptability and personalized optimization capabilities. Significant differences exist in winter minimum temperatures, humidity levels, and user water usage habits across different regions. For example, the requirements for low-temperature operation strategies differ drastically between cold, dry northern regions and cold, humid southern regions. By granting configuration permissions to these key parameters, professional engineers, after authentication, can make localized adjustments based on actual climate data and user feedback from the installation location. For instance, in areas with normal temperatures, the first environmental threshold can be appropriately increased to activate frequency conversion regulation earlier; in frigid regions, the low-frequency reference value can be lowered to extend operating time rather than pursue power; or a gentler frequency reduction gradient can be set for households with high water consumption. This configurable parameter architecture not only improves the product's performance in diverse application scenarios but also lays the technical foundation for after-sales service, energy efficiency certification optimization, and future functional iterations.

[0073] In some embodiments of this application, the first environmental threshold is set to -5°C. This value is determined based on extensive low-temperature measurement data—when the ambient temperature is below -5°C, the air-side heat exchange drops sharply, and high-frequency operation of the compressor can easily lead to excessive exhaust temperature (>120°C) or difficulty in oil return, thus reducing system reliability. Therefore, forcibly reducing the frequency below this threshold is a protection strategy that balances safety and basic hot water output. Furthermore, the low-frequency reference value is set to 30Hz. At this frequency, the compressor power consumption is approximately 40% of the rated power, which can still maintain a slow temperature rise in the water tank (approximately 1–2°C / 10min) while ensuring that the exhaust temperature remains stable within the safe range of 95±5°C, avoiding shutdown. This value has been verified through multiple rounds of cold-region testing and can operate continuously in an environment of -15°C without triggering a protective shutdown.

[0074] In some embodiments of this application, the temperature gradually decreases as the upper water temperature rises, specifically including: when the ambient temperature is ≥–5℃, the system divides the water tank into three control zones based on the upper water temperature: If the upper water temperature is <45℃, the target frequency is 40Hz (rapid heating stage). If 45℃≤upper water temperature<50℃, the target frequency drops to 32Hz (deceleration approaches the set value); If the upper water temperature is ≥50℃, the target frequency is further reduced to 25Hz (to maintain heat preservation and prevent overshoot).

[0075] This three-stage structure avoids the oscillation problem of traditional PID control when approaching the target temperature, while significantly reducing standby power consumption.

[0076] In some embodiments of this application, it is assumed that the user sets the water temperature to 52°C, the current ambient temperature is 3°C, and the water temperature at the top of the tank is 43°C. The controller determines that the ambient temperature is ≥–5°C and enters the frequency conversion adjustment mode; since the water temperature is <45°C, the target frequency is found to be 40Hz, and the fan is synchronously set to 900RPM. As heating proceeds, the water temperature at the top rises to 47°C, and the controller switches to 32Hz / 750RPM after the next cycle detection; when the water temperature reaches 51°C, it further drops to 25Hz / 600RPM to maintain the temperature. Throughout the process, the water temperature rises steadily without overshoot, and the overall energy efficiency ratio (COP) remains above 3.8.

[0077] In some embodiments of this application, the underlying operating control parameters also include oil return control parameters to proactively address the lubricating oil retention problem that may occur when the variable frequency compressor operates at low frequencies for extended periods. The compressor in a heat pump system relies on refrigerant oil for lubrication and sealing. However, under low-frequency operating conditions, the refrigerant flow rate decreases, weakening its ability to carry refrigerant oil back to the compressor. This can easily lead to lubricating oil accumulation in the evaporator or pipelines, causing oil shortage inside the compressor, which can then lead to wear, overheating, or even cylinder seizure. By incorporating the oil return control parameters into a configurable underlying parameter system, the system can intelligently trigger oil return operations based on actual operating conditions, significantly improving the long-term reliability and lifespan of the entire unit.

[0078] The controller is also configured to perform oil return control, with the following logic: when the variable frequency compressor continuously operates below the third preset frequency for a fifth preset time, its operating frequency is increased to the fourth preset frequency and maintained for a sixth preset time to perform the oil return operation, after which it returns to the operating frequency before the oil return. The third preset frequency, fourth preset frequency, fifth preset time, and sixth preset time are all oil return control parameters.

[0079] Specifically, when the variable frequency compressor operates continuously at a frequency below the third preset frequency for a fifth preset time, the controller determines that the system has entered a low-frequency steady-state operation phase. At this time, the refrigerant circulation volume is small, the oil return efficiency decreases, and there is a risk of oil stagnation. For example, setting the third preset frequency to 30 Hz and the fifth preset time to 60 minutes means that if the compressor runs continuously at a frequency of 30 Hz or lower for one hour, the oil return trigger condition is met. This judgment logic avoids frequent or unnecessary oil return actions, intervening only when there is a genuine risk of oil stagnation, thus balancing energy efficiency and protection needs.

[0080] Subsequently, the controller raises the operating frequency of the variable frequency compressor to the fourth preset frequency and maintains it for the sixth preset time to perform the oil return operation. This step effectively flushes away accumulated refrigerant oil in the pipeline and promotes its return to the compressor cavity by briefly increasing the compressor speed, enhancing the refrigerant flow rate and system pressure differential. For example, the fourth preset frequency is set to 45 Hz, and the sixth preset time is set to 3 minutes. During this high-frequency operation, the refrigerant flow rate increases significantly, the oil film is fully carried back, and due to the short duration, the impact on the water tank temperature is limited, typically causing only a fluctuation of about 0.5 to 1°C in the upper water temperature, which is almost imperceptible to the user.

[0081] After completing the oil return operation, the controller restores the variable frequency compressor to its operating frequency before the oil return, allowing it to continue its original heating task. This recovery mechanism ensures that the oil return action is only a brief intervention, without affecting the continuity of the overall heating strategy and energy efficiency targets. The entire oil return process is executed automatically by the controller without user intervention, thus resolving the potential mechanical risks under low-frequency operation while maintaining the system's intelligence and stability.

[0082] Furthermore, factors such as pipe length, elevation difference, and ambient temperature in different installation scenarios can affect the difficulty of oil return. For example, in high-rise residential buildings, the indoor unit being higher than the main unit may make oil return more difficult. By opening up these oil return control parameters, professional engineers can adjust the thresholds according to the site conditions after authorization verification. For example, in long pipe systems, the fifth preset time can be shortened to 45 minutes, or the fourth preset frequency can be increased to 50 Hz to enhance the flushing force. This configurable mechanism not only improves the reliability of the product under complex installation conditions but also provides technical support for after-sales maintenance and performance optimization.

[0083] In some embodiments of this application, the underlying operating control parameters also include exhaust temperature protection control parameters. This mechanism aims to proactively prevent safety risks caused by high-temperature operation of the variable frequency compressor. Compressor exhaust temperature is a key indicator reflecting the system's heat load, refrigerant circulation status, and lubrication reliability. Prolonged exposure to excessively high temperatures can not only accelerate refrigerant oil carbonization and reduce lubrication performance, but may also lead to motor insulation failure, valve deformation, or even compressor chamber jamming. By setting multi-level thresholds and graded frequency reduction strategies, and making relevant parameters configurable, the system can take appropriate protective measures under different overheating conditions. This avoids interruptions to the user's hot water experience due to abrupt shutdowns and effectively ensures the long-term reliability of core components.

[0084] In some embodiments of this application, the controller is also configured to perform exhaust temperature protection control, with the specific logic as follows.

[0085] (1) When the discharge temperature of the variable frequency compressor is higher than the first discharge threshold but not higher than the second discharge threshold, the controller determines that the system is in a slightly overheated state. At this time, it immediately controls the operating frequency of the variable frequency compressor to reduce the first frequency reduction amplitude. The significance of this operation is to reduce the compression work and heat dissipation per unit time by slightly reducing the compressor speed, thereby gently suppressing the discharge temperature from continuing to rise. For example, the first discharge threshold is set to 105℃, the second discharge threshold is set to 115℃, and the first frequency reduction amplitude is 5 Hz. Within this range, the system is still on the edge of safety, and there is no need to interrupt heating. Only moderate load reduction is needed to restore thermal balance, while maintaining the continuous temperature rise of the water tank to ensure that the user does not perceive any fluctuations.

[0086] (2) When the discharge temperature of the variable frequency compressor rises further, exceeding the second discharge threshold but not reaching the third discharge threshold, it indicates that the system has entered the moderate overheating danger zone. At this time, the controller executes stronger intervention measures, namely, controlling the operating frequency of the variable frequency compressor to reduce the second frequency reduction amplitude, and this frequency reduction amplitude is significantly greater than the first frequency reduction amplitude. This measure significantly reduces the compressor load, quickly reduces the heat source input, and causes the discharge temperature to drop rapidly back to a safe range. For example, the second discharge threshold is set to 115℃, the third discharge threshold is 125℃, and the second frequency reduction amplitude is 12 Hz. This step-by-step response strategy reflects the control concept of "graded early warning and gradual intervention", which avoids frequent shutdowns while maximizing the continuity of hot water supply.

[0087] (3) When the discharge temperature of the variable frequency compressor exceeds the third discharge threshold, the system faces a serious risk of overheating. Continued operation is likely to cause irreversible mechanical damage. At this time, the controller will decisively shut down the variable frequency compressor. This shutdown action is the last line of defense, used to forcibly cut off the heat source and prevent equipment damage. For example, the third discharge threshold is set to 125℃. This value is based on the maximum allowable discharge temperature limit provided by the compressor manufacturer and a 5℃ safety margin is reserved. After shutdown, the system can enter a fault lockout state and can only be restarted after user confirmation or natural cooling to a safe level to ensure operational safety.

[0088] The first exhaust threshold, second exhaust threshold, third exhaust threshold, first frequency reduction amplitude, and second frequency reduction amplitude are all incorporated into the underlying configurable parameter system as exhaust temperature protection control parameters. This design fully considers the differences in regional climate conditions, installation environment, and compressor models. For example, in high-altitude areas where thin air leads to reduced heat dissipation efficiency, or when using high back pressure refrigerant, the thresholds can be appropriately lowered to trigger protection earlier. In southern regions with excellent heat dissipation conditions, the thresholds can be slightly relaxed to improve heating efficiency. After authorization verification, engineers can flexibly adjust these parameters based on on-site measurement data, ensuring that the protection strategy accurately matches the actual operating conditions. This avoids being overly sensitive and causing malfunctions, or being too sluggish and losing its protective significance, thus achieving an optimal balance between safety, energy efficiency, and user experience.

[0089] In some embodiments of this application, the first exhaust threshold is set at 105°C as a mild overheat warning point; the second exhaust threshold is set at 115°C, representing moderate overheating requiring stronger intervention; and the third exhaust threshold is set at 125°C, the maximum safety limit, which will shut down the machine upon exceeding this limit. Furthermore, the first frequency reduction is 5 Hz, for example, from 42 Hz to 37 Hz; the second frequency reduction is 12 Hz, for example, directly from 42 Hz to 30 Hz; the frequency after reduction must not be lower than the minimum allowed operating frequency of the system (e.g., 25 Hz) to prevent deterioration of oil return.

[0090] In some embodiments of this application, after the exhaust temperature exceeds the threshold, the frequency reduction is triggered only after it lasts for more than 3 seconds to avoid malfunctions due to instantaneous fluctuations. After the frequency reduction, if the exhaust temperature drops back below the corresponding threshold and remains below it for 10 seconds, the original frequency is gradually restored. If the temperature continues to rise to a higher threshold while the frequency is reduced, a higher level of protection is implemented.

[0091] In some embodiments of this application, after shutdown, the system enters a fault lockout state, and the LED displays the fault code "E3". It can only resume operation after manual reset or after the exhaust temperature naturally cools down to below 90°C and the power is turned off and restarted. Three consecutive high-temperature shutdowns will be recorded in the fault log for easy after-sales diagnosis.

[0092] In some embodiments of this application, it is assumed that the entire unit is heating for an extended period at an ambient temperature of -3°C, with the compressor operating at 45Hz. Due to slight frost formation on the evaporator and a decrease in fan efficiency, the exhaust temperature gradually rises to 108°C, exceeding the first threshold of 105°C but not reaching 115°C. After confirming that the overheating has lasted for 3 seconds, the controller reduces the frequency from 45 Hz to 40 Hz (a reduction of 5 Hz). If the exhaust temperature continues to rise to 118°C due to deteriorating operating conditions, the system determines that it has entered the second-level protection stage and immediately further reduces the frequency to 33 Hz (a cumulative reduction of 12 Hz). Subsequently, if heat dissipation improves, the temperature drops back to 110°C and stabilizes for 10 seconds, and the frequency gradually recovers to 40 Hz. However, if the exhaust temperature surges to 127°C, exceeding the third threshold of 125°C, the controller immediately cuts off the compressor power, displays an E3 fault, and stops all heating operations until manual intervention or sufficient cooling before resetting.

[0093] In some embodiments of this application, the variable frequency control strategy parameters include the electric auxiliary heating start-up ambient temperature threshold and the hysteresis temperature. These two parameters together constitute the basis for the judgment of electric auxiliary heating coordinated control. Their function is to realize intelligent coordination between the heat pump and the electric heater, ensuring hot water supply capacity while taking into account energy efficiency optimization.

[0094] In some embodiments of this application, the controller also performs the following electric auxiliary heating coordinated control: when the ambient temperature is lower than the electric auxiliary heating start-up ambient temperature threshold, and the upper water temperature is lower than the difference between the set temperature and the hysteresis temperature, it determines whether the variable frequency compressor is already running at the maximum allowable frequency. If it is already running at the maximum allowable frequency, it controls the electric heater to be turned on.

[0095] Specifically, when the ambient temperature is below the electric auxiliary heating start-up threshold, it indicates that the heating efficiency of the air source heat pump has significantly decreased. If the upper water temperature is still below the trigger lower limit formed by subtracting the hysteresis temperature from the user-set temperature, it means that the heat pump alone cannot meet the water demand within a reasonable time. Under this premise, the controller further detects whether the variable frequency compressor is operating at the maximum allowable frequency. Only when the compressor has reached its capacity limit and still cannot raise the water temperature will the electric heater be activated as an auxiliary heat source. This logic avoids premature or ineffective activation of the electric auxiliary heating, ensuring that electric heating only intervenes when truly necessary, thereby maintaining a rapid and stable hot water output in low-temperature environments while minimizing the consumption of high-cost electricity.

[0096] In some embodiments of this application, the starting ambient temperature threshold for electric auxiliary heating is set to 5°C, because below this temperature, the heat pump's heating capacity decreases by more than 30%, making it difficult to meet rapid heating requirements when operating alone; the hysteresis temperature is set to 3°C, meaning that auxiliary heating is only considered when the upper water temperature is lower than "set temperature - 3°C", avoiding frequent start-stop heating due to small fluctuations in water temperature; the maximum allowable frequency is set to 48 Hz, which is the compressor's upper limit under the current ambient temperature, dynamically limited by the system protection logic (e.g., the upper limit will be temporarily reduced when the exhaust temperature is too high). For example, if the user sets the water temperature to 52℃, the current ambient temperature is 3℃ (below 5℃), and the upper water temperature is 47℃ (below 52 – 3 = 49℃), the controller detects that the compressor is running at 48 Hz and has not raised the water temperature for 5 minutes. It determines that the heat pump has reached its capacity limit and immediately activates the electric heater. If the ambient temperature is 8℃ (above the threshold), even if the water temperature is low, auxiliary heating will not be activated, and the high-efficiency heat pump will be used preferentially.

[0097] In some embodiments of this application, the controller also performs the following high-temperature sterilization control: heating the lower water temperature to a preset sterilization temperature range and maintaining it for a preset duration at regular intervals each week.

[0098] Specifically, the high-temperature sterilization control function aims to improve the hygiene and safety of users' water. Its function is to periodically raise the water temperature in the tank to a range sufficient to inactivate common pathogenic microorganisms and maintain this temperature for a sufficient duration to ensure sterilization effectiveness. The controller has a built-in timer mechanism, for example, automatically triggering a sterilization program once a week. In this program, the system prioritizes heat pump heating, supplemented by electric heating when necessary, to raise the water temperature in the lower part of the tank to a preset sterilization temperature range (usually between 70°C and 80°C) and maintain this temperature for a certain period (e.g., 30 minutes). The lower water temperature is chosen as the control target because the bottom of the tank is often the area where hot and cold water mixing is least complete and bacteria are most likely to proliferate; precise heating of this area ensures effective sterilization of the entire tank of water. This function requires no manual user intervention, ensuring healthy water use while intelligent scheduling avoids excessive energy efficiency impact from frequent high-temperature operation.

[0099] In some embodiments of this application, the sterilization temperature range is 70°C to 80°C, which can effectively kill 99.9% of bacteria in the water while avoiding aging of the water tank material or excessive energy consumption; the sterilization time is 30 minutes to ensure that the heat is fully conducted to the dead corners at the bottom of the water tank; it is automatically started at 2:00 AM every Sunday by default, when the electricity price is low and the probability of water use is low, reducing the impact on users.

[0100] For example, if the system detects that the entire unit is in standby mode at 2:00 AM on Sunday, it automatically enters the sterilization mode. The controller starts the compressor to heat the water in the lower part of the water tank (monitored by a sensor 150 mm from the bottom) to 75°C and maintains this temperature for 30 minutes. If the user turns on the hot water during this period, the program pauses and prioritizes water supply, then retryes on another day.

[0101] In some embodiments of this application, the controller also performs the following antifreeze protection control: in standby mode, it triggers the corresponding level of antifreeze operation logic based on the ambient temperature and the water tank temperature.

[0102] Specifically, the anti-freeze protection control addresses the freezing risk that equipment may face when idle in cold environments. Its significance lies in preventing damage to water circuits or heat exchangers due to freezing through a multi-level response mechanism. When the entire unit is in standby mode, the controller continuously monitors the ambient temperature and water tank temperature, triggering different levels of anti-freeze logic based on their combination. For example, under mildly low temperatures, if the water tank temperature is close to the freezing point but not yet dangerous, the system can simply activate a low-frequency circulating water pump to promote water flow; when the ambient temperature further decreases or the water temperature continues to drop, the compressor is activated for short-term low-power heating; if extreme low temperatures are detected and the water temperature rapidly approaches the freezing point, the electric heater is simultaneously activated for emergency insulation. This tiered anti-freeze strategy effectively prevents pipes from freezing and cracking, and avoids the energy waste associated with single full-power anti-freeze, enabling the equipment to maintain autonomous environmental adaptation and self-protection capabilities even when unused.

[0103] In some embodiments of this application, a three-level antifreeze strategy is adopted: Level 1 antifreeze: When the ambient temperature is ≤5℃ and the water temperature at the bottom of the water tank is ≥8℃, only start the circulating water pump for 2 minutes / hour to prevent local static water from freezing; Level 2 antifreeze: When the ambient temperature is ≤0℃ or the water temperature at the bottom of the water tank is ≤6℃, start the compressor at 25 Hz to maintain the water temperature above 10℃; Level 3 antifreeze: When the ambient temperature is ≤ -10℃ and the water temperature in the tank is ≤ 4℃, the electric heater will be turned on simultaneously to quickly heat the water to 15℃ at a power of 1.5kW before stopping.

[0104] For example, during winter nighttime standby, when the ambient temperature drops to -12℃ and the water temperature at the bottom of the tank is 3℃, the controller determines that the level 3 antifreeze condition is met, immediately starts the compressor (30 Hz) and turns on the electric heater. After 15 minutes, the water temperature rises to 16℃, the system exits the antifreeze mode, and returns to standby.

[0105] Secondly, refer to Figure 2 This application provides a variable frequency control interaction method for an integrated heat pump water heater, applied to the aforementioned integrated heat pump water heater, including the following steps.

[0106] Step S110: Display the main interface 100 of the variable frequency control interaction of the integrated heat pump water heater.

[0107] Among them, reference Figure 3 The main interface 100 includes frequency conversion strategy configuration control 101, operation monitoring control 102, and engineering diagnostic service control 103.

[0108] In step S110, a clearly structured and functionally distinct interactive entry point is provided to the user. The main interface 100 for variable frequency control simplifies complex system operations into intuitive graphical selections. The main interface 100 integrates three core modules: variable frequency strategy configuration control 101, operation monitoring control 102, and engineering diagnostic service control 103. These modules cater to the needs of ordinary users for strategy customization, daily operation status viewing, and in-depth debugging by professionals, respectively. This achieves operational isolation and functional focus for different user roles, lowering the barrier to entry while preserving system maintainability and optimization potential, laying the interactive foundation for subsequent intelligent control and human-machine collaboration.

[0109] Step S120: In response to the trigger command of the frequency conversion strategy configuration control 101, the frequency conversion strategy configuration sub-interface is displayed. The user-defined frequency conversion control strategy parameters are received, and based on the frequency conversion control strategy parameters, ambient temperature, and upper water temperature, a matching two-dimensional frequency control table is queried to dynamically adjust the operating frequency of the frequency conversion compressor and the speed of the DC fan. The two-dimensional frequency control table shows the frequency-water temperature mapping relationship for different ambient temperature ranges.

[0110] In step S120, seamless integration between user-defined energy-saving strategies and dynamic equipment response is achieved. When the user triggers the frequency conversion strategy configuration control 101, the system displays the frequency conversion strategy configuration sub-interface, allowing the user to input key parameters such as the electric auxiliary heating start-up ambient temperature threshold and hysteresis temperature. The controller then combines these strategy parameters, real-time ambient temperature, and water temperature at the top of the water tank to perform a matching query in the built-in two-dimensional frequency control table. This table uses ambient temperature ranges as rows and water temperature ranges as columns, pre-storing corresponding compressor frequency and fan speed combinations. This allows the system to automatically select the optimal operating point based on the current operating conditions, dynamically adjusting the operating frequency of the frequency conversion compressor and the speed of the DC fan, thereby achieving a balance between on-demand energy supply, constant temperature stability, and high-efficiency energy saving under different climates and water usage scenarios.

[0111] Step S130: Calculate the actual superheat based on the return gas temperature and the outdoor coil temperature, and dynamically control the opening of the electronic expansion valve through PID control logic.

[0112] In step S130, the refrigerant circulation system is ensured to always be in a highly efficient and safe thermodynamic state. The controller calculates the actual superheat by collecting the compressor return gas temperature and the outdoor evaporator coil temperature. This value directly reflects whether the refrigerant at the evaporator outlet has been completely vaporized. If the superheat is too low, there is a risk of liquid slugging; if it is too high, it indicates that heat exchange is not being fully utilized. The system uses PID control logic, with the target superheat as the setpoint and the actual superheat deviation as the input, to dynamically adjust the opening of the electronic expansion valve in real time, precisely controlling the refrigerant flow into the evaporator. This closed-loop control mechanism enables the system to maintain optimal evaporation performance under various ambient temperature and load changes, significantly improving the energy efficiency ratio and ensuring long-term reliable operation of the compressor.

[0113] In step S140, in response to the trigger command of the operation monitoring control 102, the operation monitoring sub-interface 200 is displayed, and the operation data is transmitted back and visualized in real time. The operation data includes the frequency of the variable frequency compressor, the water temperature change trend and the defrost event log.

[0114] In step S140, the user's awareness and trust in the equipment's operating status are enhanced. When the user clicks the operation monitoring control 102, the system brings up the operation monitoring sub-interface 200, which visualizes the key data collected in the background in real time in the form of charts or lists. This includes the current operating frequency of the variable frequency compressor, the trend of water temperature changes in the upper and lower parts of the water tank over time, and log information such as the occurrence time and duration of historical defrost events. This transparent data display not only helps users understand the hot water generation process and judge the rationality of water use, but also provides preliminary diagnostic clues when anomalies occur, improving product usability and service experience.

[0115] In step S150, in response to the trigger command of the engineering diagnostic service control 103, after the permission verification is passed, the engineering diagnostic service sub-interface is displayed, granting access to and modification permissions for the underlying operation control parameters in order to calibrate or correct the control strategy and form a closed-loop optimization.

[0116] In step S150, a closed-loop channel from on-site feedback to strategy optimization is established. When engineers or authorized technicians trigger the engineering diagnostic service control 103, the system first performs identity and permission verification, and only after successful verification is the engineering diagnostic service sub-interface opened. This interface allows access to and modification of underlying operating control parameters, such as non-stop defrosting control parameters, oil return control parameters, exhaust temperature protection threshold, and two-dimensional frequency control table configuration parameters. By calibrating or correcting these parameters using on-site measured data, the control strategy can be made more suitable for the actual installation environment and user habits, realizing the transformation from "general factory settings" to "local optimal configuration," thereby completing the continuous iteration and performance improvement of the control logic and forming a truly closed-loop optimization system.

[0117] Therefore, the variable frequency control interaction method for integrated heat pump water heaters provided in this application not only significantly improves the user experience for ordinary users, but also greatly optimizes the diagnostic and maintenance efficiency for professional engineers. For users, the system supports water temperature setting and operating mode selection through a simple and intuitive interactive interface, and provides real-time visual display of water temperature trends, defrost records, and abnormal alarms, allowing users to clearly understand the equipment status without professional knowledge, achieving convenient and worry-free daily operation.

[0118] Meanwhile, the system provides engineers with a complete engineering-level diagnostic support system: after authorization, engineers can access underlying operating parameters, manually trigger oil return or defrost tests, and perform on-site calibration and correction of core control strategies such as the two-dimensional frequency control table, non-stop defrosting logic, oil return conditions, and exhaust temperature protection thresholds. This hierarchical interactive architecture breaks through the limitations of traditional "black box control" of home appliances, enabling equipment to have the capabilities of perception, intervention, and optimization, significantly shortening troubleshooting time, improving after-sales response efficiency, and enhancing the adaptability and long-term reliability of products in diverse installation environments.

[0119] In some embodiments of this application, the variable frequency control strategy parameters include target water temperature, operating mode, electric auxiliary heating start-up ambient temperature threshold, and hysteresis temperature. In step S120, the following operations are performed in the variable frequency strategy configuration sub-interface.

[0120] Step S210: Receive the target water temperature set by the user and generate a start / stop threshold range according to the preset hysteresis logic.

[0121] In step S210, the user's subjective needs for hot water comfort are transformed into precise control boundaries that the system can execute. When the user sets the target water temperature in the variable frequency strategy configuration sub-interface, the controller does not simply use that value as the sole start / stop point. Instead, it automatically generates a start / stop threshold range based on preset hysteresis logic. For example, if the target water temperature is 52℃ and the hysteresis temperature is 3℃, the system sets the heating start threshold to 49℃ and the stop threshold to 52℃. This dual-threshold control with hysteresis effectively avoids frequent start / stop of the compressor or electric heater due to slight fluctuations in water temperature near the set point. This not only improves equipment operational stability and extends the lifespan of key components but also reduces energy waste, while ensuring stable outlet water temperature and a positive user experience.

[0122] Optionally, the hysteresis logic uses a fixed hysteresis temperature ΔT, and the start / stop threshold range is [target water temperature]. ΔT, target water temperature], where ΔT is a user-configurable or system default constant (e.g., 3℃). Heating starts when the upper water temperature is ≤ the target water temperature. ΔT, the stopping condition is that the upper water temperature is ≥ the target water temperature. This logic uses hysteresis control to prevent frequent starts and stops, which is a common technique in this field.

[0123] Step S220: Receive the operating mode selected by the user. The operating modes include standard mode, mixed mode and electric heating mode.

[0124] In standard mode, a heat pump system absorbs heat from the air to heat the water in the tank. Hybrid mode combines heat pump and electric heating. The electric heating mode controls the activation of the electric heater for auxiliary heating based on the electric auxiliary heating start-up ambient temperature threshold and hysteresis temperature.

[0125] In step S220, users are given the ability to flexibly select the optimal heating strategy based on season, environmental conditions, or water demand. Users can switch between standard mode, hybrid mode, and electric heating mode, each mode corresponding to a different energy utilization logic.

[0126] The standard mode relies entirely on the heat pump to efficiently extract heat from the air, making it suitable for scenarios with high ambient temperatures and where energy conservation is a priority. In addition, the electric heater is always disabled in the standard mode, and heating is provided solely by the heat pump.

[0127] The hybrid mode intelligently introduces electric heating assistance on the basis of heat pump, which maintains a faster heating speed and takes into account some energy efficiency advantages in low temperature environment. In the hybrid mode, when the ambient temperature is lower than the electric auxiliary heating start-up ambient temperature threshold and the compressor has reached the highest frequency, the auxiliary heating is automatically activated.

[0128] The electric heating mode does not rely solely on electric heating throughout the entire process. Instead, it combines the auxiliary electric heating activation ambient temperature threshold and hysteresis temperature to determine the conditions for activation. Auxiliary heating is only activated when the heat pump capacity is insufficient and specific temperature control conditions are met, thus ensuring uninterrupted hot water supply even in extreme climates. Through mode selection, users can independently balance energy efficiency, heating speed, and reliability, achieving personalized hot water management.

[0129] Step S230: Package the set frequency converter control strategy parameters into a control strategy package and send it to the controller to load and execute the corresponding frequency converter control logic.

[0130] In step S230, a seamless connection and strategy implementation from user interaction to equipment control are achieved. After the user completes the target water temperature setting, operating mode selection, and other parameter configuration, the system integrates all frequency converter control strategy parameters—including target water temperature, selected operating mode, electric auxiliary heating start-up ambient temperature threshold, and hysteresis temperature—into a structured control strategy package and sends it to the main controller via an internal communication protocol.

[0131] The control strategy package uses a structured data format (such as JSON or a custom binary frame) and includes fields such as target water temperature (unit: °C), operating mode identifier (0 / 1 / 2), electric auxiliary heating start-up ambient temperature threshold ( °C), hysteresis temperature ( °C), etc., along with a CRC checksum. It is sent to the main controller via internal UART or CAN bus. Upon receiving the package, the controller parses and verifies it. If the data is complete and valid, the current operating strategy is overwritten, and an acknowledgment signal is returned. This mechanism ensures the reliability and atomicity of parameter transmission, preventing control conflicts caused by partial updates.

[0132] Upon receiving the strategy package, the controller immediately parses and loads the corresponding variable frequency control logic, dynamically adjusting the compressor frequency, fan speed, electric heater start / stop conditions, and coordination rules with other subsystems. This packaging and loading mechanism ensures the integrity and consistency of user configurations, avoids control conflicts caused by parameter fragmentation, and provides a standardized data interface for subsequent remote updates, strategy backups, or fault reproduction, significantly improving the system's intelligence level and engineering maintainability.

[0133] Furthermore, after the new strategy package is loaded, the controller takes effect at the start of the next control cycle (e.g., every 2 seconds). If the current process is a critical sub-process such as defrosting, oil return, or high-temperature sterilization, the new parameters will be applied only after the process is completed to ensure operational safety. This mechanism avoids system instability caused by sudden changes in the middle of the process.

[0134] In some embodiments of this application, reference is made to Figure 4 The operation monitoring sub-interface 200 includes a real-time status display area 201, an energy efficiency trend area 202, a defrost event recording area 203, and an abnormal alarm push area 204. In step S140, the display logic of the operation monitoring sub-interface 200 has the following steps.

[0135] Step S310: Dynamically refresh the ambient temperature, upper water temperature, current operating frequency of the variable frequency compressor, DC fan speed, four-way valve status, and electric heater start / stop status through the real-time status display area 201.

[0136] In step S310, users are provided with a comprehensive and real-time understanding of the overall machine's current operating status. The real-time status display area 201 dynamically updates key parameters such as ambient temperature, upper water temperature, current operating frequency of the variable frequency compressor, DC fan speed, four-way valve status, and electric heater start / stop status. This data is continuously updated at a high refresh rate, allowing users or maintenance personnel to intuitively understand whether the equipment is in heating, defrosting, or standby mode, determine whether the heating intensity matches current needs, and quickly identify abnormal phenomena such as fan stoppage, four-way valve jamming, or accidental activation of the electric auxiliary heater. This area serves as the "dashboard" for operational monitoring, providing users with the first window to understand system behavior and perform preliminary diagnostics, significantly improving operational transparency and trust.

[0137] Optionally, all status parameters are read by the controller from the corresponding sensor or drive module at fixed intervals (e.g., every 1 second), digitally filtered (e.g., by moving average), and then sent to the interactive unit via an internal communication bus (e.g., Modbus RTU). The interactive interface updates its display at a refresh rate of no more than 2 seconds to ensure that the status seen by the user is basically synchronized with the actual operation of the equipment. For example, the status of a four-way valve is confirmed by feedback signals from the valve body, rather than relying solely on control commands, to avoid inconsistencies between the displayed status and the actual operation.

[0138] In step S320, the frequency-water temperature change curve of the variable frequency compressor is plotted based on historical operating data through the energy efficiency trend area 202 to visually demonstrate the synergistic effect of variable frequency control on energy efficiency and water output stability.

[0139] In step S320, the abstract energy efficiency performance is transformed into a visualized trend chart to help users understand the actual effect of the variable frequency control strategy. Energy efficiency trend area 202, based on historical operating data, simultaneously plots the curves of the variable frequency compressor frequency and the upper water temperature over time. For example, when the water temperature approaches the target value, the frequency decreases gradually to avoid overshoot. This visualization verifies the dynamic adjustment capability of the two-dimensional frequency control table, making energy-saving results visible and understandable, and providing data support for users to optimize water usage habits or adjust strategy parameters.

[0140] Optionally, the system cyclically caches the operating data of the most recent 7 days in the controller's non-volatile memory, with a sampling interval of 30 seconds. Each record includes a timestamp, ambient temperature (°C), upper water temperature (°C), and compressor frequency (Hz). The interactive interface calls this dataset and simultaneously plots three curves in a graph with time on the horizontal axis and dual Y-axis (water temperature / °C on the left axis and frequency / Hz on the right axis), allowing users to swipe and view any time period. This mechanism makes energy efficiency performance traceable and comparable, rather than just displaying instantaneous values.

[0141] In step S330, the start and end times, duration, water temperature difference before and after defrosting, and frequency change of the variable frequency compressor are listed in the defrosting event recording area 203, and the water temperature fluctuation range during the non-stop defrosting is highlighted.

[0142] In step S330, a traceability and performance evaluation mechanism for the defrosting process is established. The defrosting event record area 203 presents a detailed list of the start and end times, duration, water temperature difference before and after defrosting, and the complete trajectory of the variable frequency compressor frequency for each defrosting event, with special annotation of the water temperature fluctuation during non-stop defrosting. This design highlights the advantages of the non-stop defrosting technology of this application—compared to traditional shutdown defrosting which causes hot water interruption, users can directly see in this area that the water temperature fluctuates only slightly (e.g., ±1.2℃), while defrosting efficiency is still guaranteed. Simultaneously, by analyzing the frequency and duration of defrosting, it is also possible to determine whether the installation environment has excessive humidity or whether the evaporator needs cleaning, providing a basis for preventative maintenance and realizing a shift from "passive repair" to "proactive management."

[0143] Optionally, a defrost event is automatically marked as a valid event by the controller based on the condition that the four-way valve switches to defrost mode and the compressor runs continuously for ≥30 seconds; each time an event is triggered, the system automatically records the start time, end time (based on the four-way valve switching back to heating), the minimum / maximum water temperature during the period, the frequency change sequence (sampled every 10 seconds), and calculates the water temperature fluctuation amplitude (maximum value). (Minimum value). This data is stored in structured log format, with a maximum of 50 entries retained for display in the interface.

[0144] In step S340, when an abnormal alarm push area 204 detects an excessive exhaust temperature, abnormal oil return, or communication interruption, an alarm message is automatically pushed, and the corresponding time period's operating parameter snapshot can be displayed by clicking.

[0145] In step S340, a proactive safety protection and fault response mechanism is established. When the system detects risk events such as excessive exhaust temperature, abnormal oil return, or communication interruption between the controller and the interaction unit, the abnormal alarm push area 204 immediately pushes alarm information in a prominent manner. It also supports clicking to display a snapshot of operating parameters within a few seconds before and after the alarm occurrence, including the frequency, water temperature, ambient temperature, and valve status at that time. This "alarm + context" presentation method greatly shortens the fault location time. Whether it's user self-checking or remote diagnosis by engineers, the event scene can be quickly reconstructed to determine whether it's intermittent interference or a hardware defect. This function not only improves the safety and reliability of the product but also significantly reduces after-sales service costs, reflecting the technological depth of smart home appliances evolving from "function execution" to "state self-awareness and risk self-alertness."

[0146] Optionally, an excessive exhaust temperature refers to a temperature exceeding 125°C for 3 consecutive seconds; abnormal oil return refers to the compressor running continuously for 60 minutes below 30 Hz without performing an oil return operation; and communication interruption refers to the interactive unit not receiving a heartbeat packet from the controller within 5 seconds. A debouncing delay is provided before each alarm trigger to prevent false alarms due to momentary interference. The parameter snapshot contains key data within 10 seconds before and after the alarm occurrence: timestamp, exhaust temperature, return gas temperature, coil temperature, compressor frequency, electronic expansion valve opening, DC bus voltage, and four-way valve status. This snapshot is cached along with the alarm information for easy post-event analysis.

[0147] In one specific embodiment of this application, reference is made to Figure 4 Users can access the operation monitoring sub-interface of the integrated heat pump water heater via a wired controller or mobile terminal. This interface dynamically updates key parameters in real time, including ambient temperature (3℃), upper water temperature (48℃), inverter compressor operating frequency (42 Hz), DC fan speed (1200 rpm), the four-way valve being in heating mode, and the electric heater being off. When the system detects that the exhaust temperature exceeds the limit, it automatically pushes an "E3—Exhaust Temperature Protection Activated" alarm and supports viewing details. The defrost event record area fully displays the start and end time of the most recent defrost (06:18:22–06:26:47), duration (8 minutes and 25 seconds), the water temperature drop of only 0.4℃ before and after defrosting, and the compressor frequency following the non-stop logic from 30 Hz→60 Hz→30 Hz→42 Hz. Throughout the entire process, the advantages of minimal water temperature fluctuations are highlighted. At the same time, the energy efficiency trend area is presented in the form of a curve, showing the relationship between water temperature and frequency over time. This clearly reflects the synergistic effect of variable frequency control in ensuring water output stability while achieving on-demand energy saving. Thus, an intelligent monitoring system integrating real-time perception, anomaly warning, historical traceability, and energy efficiency visualization is constructed.

[0148] In some embodiments of this application, the underlying operating control parameters include: two-dimensional frequency control table configuration parameters, non-stop defrosting control parameters, oil return control parameters, and exhaust temperature protection control parameters. The engineering diagnostic service sub-interface includes permission verification controls, underlying parameter monitoring controls, control logic debugging controls, and strategy table editing controls. In step S150, the operation logic of the engineering diagnostic service sub-interface is as follows.

[0149] In step S410, in response to the trigger command of the permission verification control, the identity authentication window is displayed, the verification information entered by the engineer is received, and the engineering mode function permission is unlocked after the verification is successful.

[0150] In step S410, a secure and reliable technical access barrier is established to ensure that only authorized professionals can access the engineering diagnostic mode. When an engineer clicks the permission verification control, the system pops up an authentication window, requiring the input of specific verification information, such as a preset engineering password, a dynamic verification code, or a digital certificate bound to the device. Only after the verification information matches and the permission verification passes will the system unlock all functional permissions in the engineering mode. This mechanism effectively prevents ordinary users from accidentally manipulating underlying parameters, leading to system malfunction or performance degradation. It also ensures the security of device operation and protects the manufacturer's intellectual property rights over core control logic, laying a reliable operational foundation for subsequent advanced debugging and parameter adjustments.

[0151] In step S420, in response to the trigger command of the underlying parameter monitoring control, a real-time parameter monitoring window is displayed, continuously transmitting and displaying the variable frequency compressor discharge temperature, outdoor coil temperature, electronic expansion valve opening, superheat, and DC bus voltage.

[0152] In step S420, a high-precision, low-latency system internal status observation window is provided to engineers. By triggering the underlying parameter monitoring control, the system opens the real-time parameter monitoring window, continuously transmitting and dynamically displaying key operating data, including the inverter compressor exhaust temperature, outdoor coil temperature, electronic expansion valve opening, actual superheat, and DC bus voltage. These parameters are usually not available to ordinary users, but they are the core basis for judging whether the heat pump system's thermodynamic cycle is normal and whether the electrical drive is stable. For example, by observing the linkage between superheat and electronic expansion valve opening, it is possible to quickly determine whether the PID regulation has converged; by monitoring DC bus voltage fluctuations, grid anomalies or inverter faults can be identified. This window is equivalent to an engineer's "endoscope," allowing them to gain in-depth insight into the essence of equipment operation without external instruments, significantly improving on-site diagnostic efficiency.

[0153] In step S430, in response to the trigger command of the control logic debugging control, the debugging operation panel is displayed, providing a forced oil return test button and a manual defrost trigger button for performing the oil return or defrost debugging operation.

[0154] In step S430, engineers are given the ability to proactively intervene in and verify specific control logic to accelerate troubleshooting or functional verification. When the control logic debugging control is triggered, the system displays a debugging operation panel, which includes dedicated tools such as a forced oil return test button and a manual defrost trigger button. Clicking the forced oil return test button immediately initiates the oil return control process, regardless of whether the automatic oil return conditions are currently met, thereby verifying the compressor's frequency reduction / increase logic and oil circuit unobstructedness. Clicking the manual defrost trigger button immediately enters defrost mode to test the stability of water temperature during four-way valve switching, fan start / stop, and defrosting without shutting down the system. These debugging functions transform operating conditions that previously relied on prolonged natural operation into instantly controllable operations, significantly shortening the on-site testing cycle and improving the speed and accuracy of after-sales service response.

[0155] In step S440, in response to the trigger command of the strategy table editing control, the control strategy editing window is displayed, allowing the underlying operating control parameters to be calibrated, corrected or reconfigured, and the updated parameters are written to the controller storage unit to realize the field adaptation and closed-loop optimization of the control strategy.

[0156] In step S440, the localization and continuous optimization of the control strategy are achieved in a closed loop. By triggering the strategy table editing control, the system brings up the control strategy editing window, allowing engineers to calibrate, correct, or reconfigure underlying operating control parameters such as the two-dimensional frequency control table configuration parameters, non-stop defrosting control parameters, oil return control parameters, and exhaust temperature protection control parameters. For example, in high-humidity areas, the defrosting duration can be extended; in cold regions, the frequency reference value at low temperatures can be adjusted; or the protection threshold can be adjusted based on the measured exhaust temperature. After editing, the updated parameters can be directly written to the controller's non-volatile storage unit, enabling the equipment to immediately operate according to the new strategy. This field-programmable capability breaks the limitations of traditional products being "fixed at the factory," allowing the same hardware platform to flexibly adapt to diverse installation environments and user needs. It truly realizes a technological leap from "general design" to "precise matching" and provides a feasible path for performance iteration throughout the product's lifecycle.

[0157] In summary, the integrated heat pump water heater and its variable frequency control interaction method provided in this application have the following technical effects.

[0158] This solution significantly improves overall system performance through multi-dimensional sensing and intelligent control. Based on temperature sensors at the top and bottom of the water tank and ambient temperature, the system dynamically queries a two-dimensional frequency control table to precisely adjust the frequency of the inverter compressor and the speed of the DC fan. Simultaneously, it calculates the actual superheat based on the return air temperature and outdoor coil temperature, using PID logic to control the opening of the electronic expansion valve in real time, achieving efficient heat exchange and stable operation. Combining standard, hybrid, and electric heating operating modes, and introducing an electric auxiliary heating collaborative control strategy, the equipment can balance energy efficiency, heating speed, and hot water continuity under different climatic conditions. The innovative non-stop defrosting logic maintains a relatively stable water temperature during defrosting by adjusting the compressor, fan, and four-way valve in stages, completely avoiding hot water interruptions. Oil return control and multi-stage exhaust temperature protection mechanisms ensure compressor lubrication safety and thermal management reliability from the ground up, effectively extending the lifespan of core components.

[0159] This solution further establishes a dual-channel interaction system through the wired control unit and mobile terminal, enabling tiered operation for users and engineers: ordinary users can easily set target water temperature and operating mode, and monitor operating status and defrost records in real time; authorized engineers can access and modify underlying operating control parameters, including the two-dimensional frequency table, defrost sequence, oil return conditions, and protection thresholds, to complete on-site calibration and closed-loop optimization. Therefore, this application not only addresses several shortcomings of existing products in terms of energy efficiency, comfort, reliability, and intelligence, but also breaks down the technical barriers of "ease of use" and "adjustability," providing a complete and feasible technical path for high-performance, highly adaptable operation of integrated heat pump water heaters in diverse environments.

[0160] It should be noted that in all specific embodiments of this application, all data processing activities related to user identity or personal characteristics, such as user information, user behavior data, historical data, and location information, will be conducted in accordance with the principles of legality, legitimacy, and necessity. All data collection, use, storage, and processing will be subject to compliance with applicable national and regional laws, regulations, and industry standards, and informed consent from users will be obtained in a clear and explicit manner before processing. For the processing of sensitive personal information, separate consent from users will be obtained through prominent means such as pop-up prompts and independent confirmation pages. If any processing conflicts with laws and regulations, the laws and regulations will prevail, and necessary data processing will only be carried out within the scope permitted by laws and regulations, ensuring that all data-based applications, analyses, and technical implementations are conducted within the scope permitted by laws and regulations.

[0161] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.

[0162] Furthermore, although this application is described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding this application. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of ordinary skill of an engineer. Therefore, those skilled in the art can implement the application set forth in the claims using ordinary skill. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of this application, which is determined by the full scope of the appended claims and their equivalents.

[0163] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several programs to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned 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.

[0164] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable programs for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, a program execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can retrieve and execute a program from or in conjunction with such a program execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can mean any means that can contain, store, communicate, propagate, or transmit a program for use by or in conjunction with a program execution system, apparatus, or device.

[0165] More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Additionally, computer-readable media can even be paper or other suitable media on which programs can be printed, for example, by optically scanning the paper or other media, then editing, interpreting, or, if necessary, processing it in a suitable manner to obtain the program electronically, and then storing it in computer memory.

[0166] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0167] In the foregoing description of this specification, the reference to terms such as "one embodiment / implementation," "another embodiment / implementation," or "certain embodiments / implementations," etc., indicates that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in an embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0168] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0169] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. An integrated heat pump water heater, characterized in that, include: Variable frequency compressor, DC fan, four-way valve, electric heater, water tank, electronic expansion valve and controller; The water tank is equipped with a first temperature sensor for detecting the upper water temperature and a second temperature sensor for detecting the lower water temperature. The controller establishes a communication connection with the drive-by-wire interaction unit and the mobile application; the drive-by-wire interaction unit and the mobile application provide an interactive interface for receiving frequency conversion control strategy parameters input by the user, transmitting real-time operating data, and granting access to and modification permissions for the underlying operating control parameters after authorization verification. The controller is configured to: In hot water heating mode, based on preset variable frequency control strategy parameters, ambient temperature and upper water temperature, the controller queries the two-dimensional frequency control table stored in the controller to dynamically adjust the operating frequency of the variable frequency compressor and the speed of the DC fan; in the two-dimensional frequency control table, different ambient temperature ranges correspond to frequency-water temperature mapping relationships. The actual superheat is calculated based on the return gas temperature and the outdoor coil temperature, and the opening of the electronic expansion valve is dynamically controlled through PID control logic.

2. The integrated heat pump water heater according to claim 1, characterized in that, The underlying operating control parameters include non-stop defrosting control parameters; The controller is also configured to perform a non-stop defrosting operation, specifically: When the defrosting conditions are met, the operating frequency of the variable frequency compressor is reduced to the first preset frequency. After a first preset time delay, the DC fan is turned off and the four-way valve is controlled to switch to the defrosting mode. After a second preset time delay, the variable frequency compressor is increased to the second preset frequency to perform defrosting. When the defrosting exit conditions are met, the operating frequency of the variable frequency compressor is reduced to the first preset frequency. After a third preset time, the four-way valve is controlled to return to the heating mode and the DC fan is turned on. After a fourth preset time, the variable frequency compressor is restored to the normal heating operating frequency before defrosting. Wherein, the first preset frequency, the second preset frequency, the first preset time, the second preset time, the third preset time, and the fourth preset time are all the non-stop defrosting control parameters.

3. The integrated heat pump water heater according to claim 1, characterized in that, The underlying operation control parameters also include two-dimensional frequency control table configuration parameters; The construction rules for the two-dimensional frequency control table are as follows: When the ambient temperature is below the first environmental threshold, the operating frequency of the variable frequency compressor is fixed at the low-frequency reference value. When the ambient temperature is not lower than the first environmental threshold, the target operating frequency of the variable frequency compressor decreases step by step as the upper water temperature increases. The first environmental threshold, the low-frequency reference value, and the target operating frequencies at each level are all configuration parameters of the two-dimensional frequency control table.

4. The integrated heat pump water heater according to claim 1, characterized in that, The underlying operating control parameters also include oil return control parameters; The controller is also configured to perform oil return control, specifically: When the variable frequency compressor runs continuously below the third preset frequency for a fifth preset time, its operating frequency is controlled to be increased to the fourth preset frequency and maintained for a sixth preset time to perform the oil return operation, and then it is restored to the operating frequency before the oil return. The third preset frequency, the fourth preset frequency, the fifth preset time, and the sixth preset time are all oil return control parameters.

5. The integrated heat pump water heater according to claim 1, characterized in that, The underlying operating control parameters also include exhaust temperature protection control parameters; The controller is also configured to perform exhaust temperature protection control, specifically: When the discharge temperature of the variable frequency compressor is higher than the first discharge threshold but not higher than the second discharge threshold, the operating frequency of the variable frequency compressor is controlled to reduce the first frequency reduction magnitude. When the discharge temperature of the variable frequency compressor is higher than the second discharge threshold but not higher than the third discharge threshold, the operating frequency of the variable frequency compressor is controlled to decrease by a second frequency reduction magnitude, which is greater than the first frequency reduction magnitude. When the discharge temperature of the variable frequency compressor is higher than the third discharge threshold, the variable frequency compressor is controlled to stop. Wherein, the first exhaust threshold, the second exhaust threshold, the third exhaust threshold, the first frequency reduction amplitude, and the second frequency reduction amplitude are all exhaust temperature protection control parameters.

6. The integrated heat pump water heater according to claim 1, characterized in that, The variable frequency control strategy parameters include the electric auxiliary heating start-up ambient temperature threshold and hysteresis temperature; The controller also performs the following control functions: Electric auxiliary heating coordinated control: When the ambient temperature is lower than the electric auxiliary heating start-up ambient temperature threshold and the upper water temperature is lower than the difference between the set temperature and the hysteresis temperature, it is determined whether the variable frequency compressor is already running at the maximum allowable frequency; if it is already running at the maximum allowable frequency, the electric heater is controlled to be turned on. High-temperature sterilization control: The lower water temperature is heated to a preset sterilization temperature range and maintained for a preset duration at regular intervals each week; Anti-freeze protection control: In standby mode, the corresponding level of anti-freeze operation logic is triggered based on the ambient temperature and water tank temperature.

7. A variable frequency control interactive method for an integrated heat pump water heater, applied to the integrated heat pump water heater as described in any one of claims 1 to 6, characterized in that, Includes the following steps: The main interface for the variable frequency control interaction of the integrated heat pump water heater is displayed. The main interface includes variable frequency strategy configuration controls, operation monitoring controls, and engineering diagnostic service controls. In response to the trigger command of the frequency conversion strategy configuration control, the frequency conversion strategy configuration sub-interface is displayed to receive the frequency conversion control strategy parameters set by the user; Based on the variable frequency control strategy parameters, ambient temperature, and upper water temperature, a matching two-dimensional frequency control table is queried to dynamically adjust the operating frequency of the variable frequency compressor and the speed of the DC fan. In the two-dimensional frequency control table, different ambient temperature ranges correspond to frequency-water temperature mapping relationships. At the same time, based on the return air temperature and outdoor coil temperature, the actual superheat is calculated, and the opening of the electronic expansion valve is dynamically controlled through PID control logic. In response to the trigger command of the operation monitoring control, the operation monitoring sub-interface is displayed, and the operation data is transmitted back and visualized in real time. The operation data includes the frequency of the variable frequency compressor, the water temperature change trend, and the defrost event log. In response to the trigger command of the engineering diagnostic service control, after the permission verification is passed, the engineering diagnostic service sub-interface is displayed, granting access to and modification permissions for the underlying operation control parameters, so as to calibrate or correct the control strategy and form a closed-loop optimization.

8. The variable frequency control interactive method for an integrated heat pump water heater according to claim 7, characterized in that, The variable frequency control strategy parameters include target water temperature, operating mode, electric auxiliary heating start-up ambient temperature threshold, and hysteresis temperature. Perform the following operations in the frequency conversion strategy configuration sub-interface: Receive the target water temperature set by the user and generate the start / stop threshold range according to the preset hysteresis logic; The system receives the user-selected operating mode, which includes standard mode, hybrid mode, and electric heating mode. The standard mode relies on a heat pump system to absorb heat from the air to heat the water in the tank; the hybrid mode combines the heat pump and electric heating working together; the electric heating mode is used to control the electric heater to start for auxiliary heating based on the electric auxiliary heating start-up ambient temperature threshold and hysteresis temperature. The set frequency converter control strategy parameters are packaged into a control strategy package and sent to the controller to load and execute the corresponding frequency converter control logic.

9. The variable frequency control interactive method for an integrated heat pump water heater according to claim 7, characterized in that, The operation monitoring sub-interface includes a real-time status display area, an energy efficiency trend area, a defrost event recording area, and an abnormal alarm push area. The display logic of the operation monitoring sub-interface is as follows: The real-time status display area dynamically refreshes the ambient temperature, upper water temperature, current operating frequency of the variable frequency compressor, DC fan speed, four-way valve status, and electric heater start / stop status. Based on historical operating data, the frequency-water temperature change curve of the variable frequency compressor is plotted through the energy efficiency trend area to visually demonstrate the synergistic effect of variable frequency control on energy efficiency and water output stability. The defrost event recording area lists the start and end times, duration, water temperature difference before and after defrost, and frequency change of the variable frequency compressor for each defrost event, and highlights the water temperature fluctuation range during non-stop defrosting. The abnormal alarm push area automatically pushes alarm information when exhaust temperature exceeds the limit, oil return is abnormal, or communication is interrupted, and supports clicking to display a snapshot of the operating parameters for the corresponding time period.

10. The variable frequency control interactive method for an integrated heat pump water heater according to claim 7, characterized in that, The underlying operating control parameters include: two-dimensional frequency control table configuration parameters, non-stop defrosting control parameters, oil return control parameters, and exhaust temperature protection control parameters; The engineering diagnostic service sub-interface includes a permission verification control, a low-level parameter monitoring control, a control logic debugging control, and a strategy table editing control. The operation logic of the engineering diagnostic service sub-interface is as follows: In response to the trigger command of the permission verification control, an identity authentication window is displayed, the verification information input by the engineer is received, and the engineering mode function permission is unlocked after the verification is successful. In response to the trigger command of the underlying parameter monitoring control, a real-time parameter monitoring window is displayed, continuously transmitting and displaying the variable frequency compressor discharge temperature, outdoor coil temperature, electronic expansion valve opening, superheat, and DC bus voltage. In response to the trigger command of the control logic debugging control, the debugging operation panel is displayed, providing a forced oil return test button and a manual defrost trigger button for performing oil return or defrost debugging operations; In response to the trigger command of the strategy table editing control, the control strategy editing window is displayed, allowing the underlying operating control parameters to be calibrated, corrected or reconfigured, and the updated parameters are written to the controller storage unit to achieve field adaptation and closed-loop optimization of the control strategy.

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