A control method for opening a fan during a defrosting process of an air source heat pump unit

Abstract

A kind of control method of fan opening in air source heat pump unit defrosting process, this method includes the following steps: S1, after unit enters defrosting state, first by unit control system automatically identify the system type of current unit, wind wheel type, and determine unit type in combination with preset control parameter P08, P07;S2, according to the identification result of step S1, determine the fan type that needs to be started in defrosting process;S3, preset control parameter;S4, by unit temperature acquisition module real-time acquisition upper coil temperature;S5, for the failure condition of upper coil temperature sensor, execute special fault control logic;S6, for only having high-low wind function unit, execute the following special control logic alone, adapt to its fan structure characteristics.The present application can realize the precision, closed-loop control of fan, improve defrosting efficiency, reduce operating energy consumption, ensure that unit can be stably operated under different working conditions, different fault scenarios, prolong the service life of unit.

Description

Technical Field

[0001] This invention relates to the field of heat pump unit control technology, and in particular to a control method for the operation of the fan during the defrosting process of an air source heat pump unit. It is applicable to the precise control of the fan during the defrosting process of various air source heat pump units (including dual-supply cooling and heating, dual-supply single heating, hot water units, and tri-supply units). Background Technology

[0002] When air source heat pump units operate in low-temperature and high-humidity environments, frost easily forms on the surface of the outdoor heat exchanger. Frost increases the heat exchanger's thermal resistance, reduces the unit's heat exchange efficiency, increases operating energy consumption, and in severe cases, can lead to abnormal unit circulation and shutdown protection. Therefore, the defrosting process is a crucial aspect of winter operation for air source heat pump units, directly affecting the unit's operational stability and performance. As a key component in the defrosting process, the fan's operating status (on / off, operating frequency / speed) directly impacts defrosting efficiency, defrosting effect, and unit energy consumption. Properly controlling the fan's operating status is the core means to improve defrosting performance.

[0003] In the defrosting process of existing air source heat pump units, fan control often employs standardized and fixed logic. This fails to adequately consider unit type determination parameters (such as P08 and P07) to differentiate the upper coil temperature detection differences between different units. Furthermore, it doesn't clearly define the detection points for upper coil temperature under different parameter combinations, or whether they even exist. Moreover, the control parameters (P01-P06) are mostly fixed values, not adjusted in real-time according to different unit models and ambient temperatures. This results in insufficient targeting and poor adaptability of the fan control. For example, some control methods fail to determine the unit type based on P08 and P07 parameters, uniformly using a single temperature detection point to control the fan, easily leading to incomplete defrosting or ineffective fan operation. Some control methods lack adaptation logic for dual-system units without upper and lower coil temperature detection, causing chaotic fan control in dual-system units. Simultaneously, fixed control parameters cannot adapt to the differentiated needs of different unit models (such as water heaters and dual-supply systems) and different ambient temperatures (such as low temperatures in the north and warm and humid environments in the south), further reducing defrosting efficiency and increasing energy consumption. Furthermore, existing technologies lack adequate emergency control measures for upper coil temperature sensor malfunctions. In case of failure, they often employ shutdown protection or fixed fan operation modes, which either disrupts user experience, wastes energy, or even exacerbates unit frosting, thus affecting unit lifespan. Additionally, the control parameters in existing methods are not clearly defined, lacking explicit explanations of the meaning and logical relationships of parameters P08 and P07, making them prone to misoperation and control logic failure.

[0004] Therefore, there is an urgent need for a method to determine the unit type by combining P08 and P07 parameters, clarify the upper coil temperature detection standard under different parameter combinations, adapt to different unit types, system types and impeller types, have clear parameter settings, allow P01-P06 parameters to be adjusted according to different models and ambient temperatures, and have complete fault emergency control functions for the defrosting fan control of air source heat pump units, in order to solve the shortcomings of existing technologies and improve the defrosting performance and operational stability of the units. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of existing technologies by providing a control method for the operation of the defrost fan in an air source heat pump unit. This method specifically addresses the technical problems of existing defrost fan control, such as the lack of integration of P08 and P07 parameters to determine the unit type, unclear upper coil temperature detection standards, fixed control parameters (P01-P06) that cannot be adjusted according to different unit models and ambient temperatures, poor control specificity and adaptability, ambiguous control parameters, and poor operational stability under fault conditions. This invention achieves precise, closed-loop control of the fan, improves defrost efficiency, reduces operating energy consumption, ensures stable operation of the unit under different operating conditions and fault scenarios, and extends the service life of the unit.

[0006] The technical problem to be solved by this invention is achieved through the following technical solution. This invention is a method for controlling the operation of a fan during the defrosting process of an air source heat pump unit, the method comprising the following steps: S1. After the unit enters the defrosting state, the unit control system first automatically identifies the current system type and rotor type of the unit, and determines the unit type by combining the preset control parameters P08 and P07. The system type includes single system and dual system, and the rotor type includes dual rotor and single rotor. The unit type is determined by the combined use of parameters P08 and P07. The P08 parameter indicates the unit type selection: 0: dual-supply (heating and cooling), 1: tri-supply (heating and cooling), 2: hot water unit, 3: dual-supply (heating only). The P07 parameter indicates whether the water tank temperature probe is enabled or disabled. When P08=0 or 3, P07=0, indicating dual-supply. When P08=2, P07=1, indicating hot water unit. When P08=1, it indicates tri-supply, and the existing tri-supply unit defrost fan control logic applies. The identification process is completed through the unit's preset type identification module and parameter detection module, providing a foundation for the accurate execution of subsequent wind turbine control logic; S2. Based on the identification results of step S1, determine the type of fan to be turned on during the defrosting process: for dual-fan units, turn on the upper fan Fan1; for single-fan units, turn on the DC fan 1. The starting logic of the upper fan Fan1 is controlled by the control parameter P03, which has a value range of [0-20]. When P03=0, the starting logic of the upper fan Fan1 is disabled, meaning that the upper fan Fan1 does not execute any defrosting-related control logic during the defrosting process. The starting logic of the DC fan 1 is also controlled by the control parameter P03, which has a value range of [0-20]. When P03=0, the starting logic of the DC fan 1 is disabled, meaning that during the defrosting process of the single turbine unit, the DC fan 1 does not execute the starting logic by default, and only executes control according to the subsequent logic when P03≠0. P03 needs to have its parameters adjusted according to the current unit model and actual ambient temperature to adapt to the frosting speed and defrosting requirements under different operating conditions. S3. Preset control parameters, including P01, P02, P03, P04, P05, P06, P07, and P08. Each parameter is a digital parameter recognizable by the unit control system. Among them, parameter P07 means enabling or disabling the water tank temperature probe, and parameter P08 means selecting the unit type: 0: dual-supply cooling and heating, 1: triple-supply, 2: hot water unit, 3: dual-supply heating only. P08 and P07 are related: when P08=0 or 3, P07=0; when P08=2, P07=1. P01, P02, P03, P04, P05, and P06 need to be adjusted according to different unit models and actual operating environment temperature. The remaining parameters can be reasonably adjusted according to the actual operating environment and defrosting requirements of the unit, and the adjustments must be saved and taken effect through the unit control system. S4. The upper coil temperature is collected in real time through the unit temperature acquisition module. The upper coil temperature is determined according to parameters P08 and P07 and system type: when P08=0 or 3 and P07=0, i.e., dual-supply, the upper coil temperature of a single system is T16, and there is no corresponding upper coil temperature detection point for dual-system units; when P08=2 and P07=1, i.e., hot water unit, the upper coil temperature of a single system is T14, and there is no corresponding upper coil temperature detection point for dual-system units. The acquisition frequency is real-time to ensure the real-time and accuracy of temperature data. Combined with preset control parameters P01, P02, and P03, the fan operation status is precisely controlled to realize the automatic switching of fan operation mode. If the dual-system unit does not have a corresponding upper coil temperature detection point, the control logic based on the upper coil temperature in this step will not be executed, and the fan will remain in the initial state or the off state. S5. In case of a fault in the upper coil temperature sensor, execute dedicated fault control logic: The unit control system monitors the sensor status in real time. When a fault is detected in the upper coil temperature sensor, fault code Ed1 is immediately reported. At the same time, the unit continues to run without stopping to avoid unit shutdown due to sensor failure and affect user operation. If the unit has entered defrosting mode and the effective defrosting time is >60s, the emergency control logic will be executed immediately: control the upper fan Fan1 to run at frequency P05, or control the DC fan 1 to start through the fixed frequency port DO16, with the starting time strictly P06 seconds, and then shut down for 60-P06 seconds, and repeat the start and stop operation until the unit exits the defrosting mode. After exiting the defrosting mode, the fault control logic will automatically terminate. If there is no corresponding upper coil temperature in the dual system, the fault control logic of this step will not be triggered; P05 and P06 parameters need to be adjusted according to the current model and ambient temperature to avoid energy waste or defrosting interruption in case of fault; S6. For units that only have high and low wind functions, the following dedicated control logic is executed separately to adapt to their fan structure characteristics: In high-wind mode, the down fan is turned on through port DO4 and the up fan is turned on through port DO16. The up and down fans start and stop synchronously. In low-wind mode, the down fan is turned on through port DO1 and the up fan is turned on through port DO15. The up and down fans also start and stop synchronously, ensuring that the up and down fans work together during the defrosting process, improving the uniformity and efficiency of defrosting. In this mode, P01-P03 need to adjust parameters according to the current model and ambient temperature to ensure accurate switching between high and low fan modes.

[0007] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: Regarding the control method for the operation of the fan during the defrosting process of the air source heat pump unit described above, in step S1, the temperature detection parameters are different for different unit types. The specific detection parameters and requirements are as follows, and the temperature detection parameters strictly match the P08 and P07 parameters: When P08=2 and P07=1, it is determined to be a hot water machine: the water tank temperature T16, upper coil temperature, economizer outlet pipe 2 temperature, and heat exchanger temperature need to be monitored in real time; for single-system hot water machines, the upper coil temperature is monitored at the corresponding monitoring point T14, and the economizer outlet pipe 2 temperature is not monitored; for dual-system hot water machines, the upper coil temperature is not monitored, but the economizer outlet pipe 2 temperature is monitored at the corresponding monitoring point T14; the heat exchanger temperature is a fixed value of 25℃, which does not need to be monitored in real time and is preset by the unit control system. When P08=0 or 3 and P07=0, it is determined to be a dual-supply system: no water tank temperature detection is required, but the upper coil temperature, economizer outlet pipe 2 temperature, and heat exchanger temperature must be detected in real time; for a single-system dual-supply system, the upper coil temperature is detected at detection point T16, and the economizer outlet pipe 2 temperature is not detected; for a dual-system dual-supply system, the upper coil temperature is not detected, but the economizer outlet pipe 2 temperature is detected at detection point T14; for the heat exchanger temperature, the single-system dual-supply system corresponds to detection point T14, and the dual-system dual-supply system corresponds to detection point T16. When the heat exchanger temperature detection function is disabled, the heat exchanger temperature is fixed at 25℃, which is preset by the unit control system.

[0008] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: For the control method of the fan during the defrosting process of the air source heat pump unit described above, in step S2, the value range of P03 is [0-20], which is a non-negative integer parameter. P03 needs to be adjusted according to different models and actual ambient temperature. When P03≠0, the upper fan Fan1 of the dual-fan unit is turned on and its operating state is adjusted according to the logic of step S4 during the defrosting process. The larger the value of P03, the higher the sensitivity of the upper fan Fan1. When P03=0, the upper fan Fan1 of the dual-fan unit does not execute the above control logic during the defrosting process and always maintains the closed state or the initial state. If there is no corresponding upper coil temperature in the dual system, the upper fan Fan1 will maintain the initial state or the closed state regardless of the value of P03.

[0009] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: For the control method of the fan during the defrosting process of the air source heat pump unit described above, in step S4, the fan operating status is precisely controlled according to the following logic to realize the automatic switching of the fan operating mode: (1) High wind mode: When the collected upper coil temperature is ≥ P02, control the upper fan Fan1 to run stably at frequency P05, or control the DC fan 1 to start stably through the fixed frequency port DO16; the frequency fluctuation range of the upper fan Fan1 shall not exceed ±1Hz, and the speed of the DC fan 1 shall remain constant after it is turned on to ensure the defrosting efficiency in high wind mode; P02 and P05 need to be adjusted according to the current model and ambient temperature to adapt to different frosting speeds; (2) Low wind mode: When P02-P03 > the collected upper coil temperature ≥ P01, control the upper fan Fan1 to run stably at frequency P04, or control the DC fan 1 to start stably through the fixed frequency port DO15; in this mode, the fan operating power is lower than that in high wind mode, and energy consumption is reduced to the maximum extent while ensuring the defrosting effect; P01, P03, and P04 need to be adjusted according to the current model and ambient temperature to balance the defrosting effect and energy consumption; (3) Shutdown mode: When the collected upper coil temperature is ≤ P01-P03, control the upper fan Fan1 to shut down immediately, or control the fixed frequency ports DO16 and DO15 of DC fan 1 to shut down immediately; the shutdown action delay shall not exceed 1 second to avoid cold air from continuously entering the unit and causing frosting to intensify; P01 and P03 need to be adjusted according to the current model and ambient temperature to avoid incomplete defrosting or ineffective fan shutdown; (4) Original mode: When the above conditions (1), (2) and (3) are not met, the fan maintains the current operating state and does not switch modes, so as to avoid the instability of unit operation caused by frequent switching of operating modes and reduce the start-up and shutdown losses of the fan.

[0010] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: For the control method of turning on the fan during the defrosting process of the air source heat pump unit described above, in step S4, the fixed frequency control of DC fan 1 is only executed in the single turbine unit, and when P03≠0, DC fan 1 is turned on and the operating port is switched according to the logic of step S4, and the port switching delay does not exceed 0.5 seconds; when P03=0, DC fan 1 does not execute the above control logic during the defrosting process, and is kept in the off state by default, and is not affected by the temperature change of the upper coil; if there is no corresponding upper coil temperature in the dual system, then no matter what the value of P03 is, DC fan 1 will maintain the initial state or the off state; P01, P02, P03, P04, and P05 need to be adjusted according to the current model and ambient temperature to ensure that the control logic is adapted to the current operating conditions.

[0011] The technical problem to be solved by the present invention can also be further achieved by the following technical solution: For the control method of the fan during the defrosting process of the air source heat pump unit described above, in step S5, the fault control logic is triggered only when the upper coil temperature sensor is faulty and the unit has a corresponding upper coil temperature detection, that is, a single system dual supply, a single system hot water machine, and the fault detection adopts a dual verification mechanism to ensure accurate fault judgment and avoid false alarms. The cycle of the cyclic start-stop operation is fixed at 60 seconds. The start time is set by P06, and the value of P06 is in the range of [10-50] seconds. P06 needs to be adjusted according to different models and actual ambient temperature. The stop time is the difference between 60 seconds and P06. The cyclic operation continues until the unit exits the defrost state. At this time, the fault control logic will automatically terminate, and the unit will continue to report fault code Ed1 until the sensor fault is resolved.

[0012] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: For the control method of the fan on during the defrosting process of the air source heat pump unit described above, in step S6, the upper and lower fan on-state logic of the high and low fan units is only for the defrosting process and corresponds one-to-one with the high and low fan modes in step S4. The on-state of the lower fan switches synchronously with the upper fan, and the switching delay does not exceed 1 second. After the defrosting process is completed, the upper and lower fans automatically return to the operating state before defrosting. If the fan was in the off state before defrosting, it remains in the off state after defrosting. If there is no corresponding upper coil temperature in the dual system, the high and low fan units maintain the initial operating state. The parameters of P01-P03 corresponding to the high and low fan units need to be adjusted according to the model and ambient temperature to ensure the coordinated operation effect of the upper and lower fans.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Highly adaptable: This invention accurately determines the unit type by combining parameters P08 and P07, clearly identifying the detection point and presence of the upper coil temperature under different parameter combinations and system types. Simultaneously, parameters P01-P06 can be adjusted according to different unit models and ambient temperatures. It fully considers the structural differences and operational requirements of unit types (dual-supply heating and cooling, dual-supply heating and cooling alone, hot water units, tri-supply), system types (single system, dual system), and impeller types (dual impeller, single impeller), as well as the differences in operating conditions under different ambient temperatures. It designs differentiated fan control logic and distinguishes between dedicated control methods for high and low voltage fan units, solving the problems of insufficient adaptability, unclear upper coil temperature detection standards, and fixed parameters in existing control methods. It can be widely applied to various air source heat pump units, adapting to different engineering application scenarios and climatic environments. 2. Precise and efficient control: This invention combines the upper coil temperature of the corresponding unit with parameters P08 and P07, and the P01-P06 control parameters which can be adjusted according to the model and ambient temperature, to achieve automatic closed-loop switching of four fan modes: high wind, low wind, off, and original. This precisely matches the frost amount requirements of different defrosting stages and the operating requirements of different working conditions. While ensuring thorough defrosting, it minimizes the energy consumption of the fan and improves defrosting efficiency. Actual tests show that this invention can improve defrosting efficiency by 15%-20% and reduce fan energy consumption by 10%-15%. 3. High operational stability: This invention has a complete emergency control logic for upper coil temperature sensor failure, clearly defined fault triggering conditions (only for units with upper coil temperature detection), and adopts a dual fault verification mechanism. The unit does not stop during a fault, and the defrosting process is ensured by cyclically starting and stopping the fan. In addition, the parameters of P05 and P06 involved in the emergency control can be adjusted according to the model and ambient temperature to avoid fan runaway and defrosting interruption due to sensor failure. At the same time, it reduces the impact of the fault on the user and significantly improves the reliability and stability of the unit operation. 4. Convenient operation and strong maintainability: This invention clarifies the value range, function and setting requirements of each control parameter, and elaborates on the meaning and related logic of parameters P08 and P07. It also clarifies that parameters P01-P06 need to be adjusted according to different models and ambient temperatures. The parameter adjustment is simple and easy to understand, avoiding the impact of misoperation on the control logic. At the same time, the fan control logic is fully automated and does not require manual intervention, reducing operation and maintenance costs. In case of failure, the fault code provides accurate prompts, which facilitates the staff to quickly troubleshoot the fault. Attached Figure Description

[0014] Figure 1 This is a control diagram of the defrosting fan of the dual-fan water heater (single system) of the present invention; Figure 2 This is a control diagram of the single-impeller dual-supply (dual-system) defrosting fan of the present invention; Figure 3 This is a flowchart of the defrosting fan control for the high and low temperature fan unit (dual impeller, dual-supply single heating, single system) of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1: Defrosting fan control of a dual-fan water heater (single system) (see attached) Figure 1 ) In this embodiment, the unit's preset parameters are: P08=2 (hot water machine), P07=1 (water tank temperature probe enabled), indicating it is a hot water machine; the system type is a single system, the impeller type is a dual impeller, suitable for the low temperature and high humidity environment in northern winters (ambient temperature -10℃~5℃, relative humidity 60%~80%). Based on this model and ambient temperature, the control parameters are adjusted as follows: P01=5℃ (appropriately increased in low temperature environment), P02=15℃, P03=10 (increase response sensitivity in low temperature and high humidity environment), P04=30Hz (appropriately increased in low temperature environment), P05=50Hz (appropriately increased in severe frosting), P06=30s (appropriately extended in low temperature environment).

[0017] The control process is as follows, with each step executed sequentially: S1. Within 1 second after the unit enters the defrosting state, the control system identifies the system type as a single system and the impeller type as a dual impeller. Combined with P08=2 and P07=1, the unit is determined to be a hot water unit. At the same time, it is confirmed that the coil temperature of the single system hot water unit is T14. S2. Since the wind turbine type is a dual wind turbine, it is determined that the upper fan Fan1 will be turned on, P03=10≠0 (the parameters have been adjusted according to the low temperature and high humidity of the northern environment), and the logic for turning on the upper fan Fan1 will be activated. The subsequent control will be executed according to the logic of step S4. S3. The preset parameters have been set and saved through the unit control system and are effective. At the same time, the temperature detection module is started to detect the relevant temperature parameters of the water heater in real time: water tank temperature T16, upper coil temperature T14 (single system water heater), heat exchanger temperature (fixed at 25℃). The temperature acquisition frequency is real time. S4, the temperature acquisition module collects the upper coil temperature T14 in real time. The control system, in conjunction with preset parameters P01, P02, and P03 (all parameters have been adjusted according to the model and ambient temperature), determines the mode and controls the operation of the upper fan Fan1. (1) When T14≥15℃ (P02), the upper fan Fan1 operates stably at a frequency of 50Hz (P05, parameters have been adjusted according to the model and ambient temperature), with frequency fluctuation not exceeding ±1Hz, to accelerate air circulation and improve defrosting efficiency; (2) When 15℃-10℃>T14≥5℃ (P01), that is, 5℃≤T14<6℃, the upper fan Fan1 operates stably at a frequency of 30Hz (P04, the parameters have been adjusted according to the model and ambient temperature) to reduce energy consumption while ensuring the defrosting effect; (3) When T14≤5℃-10℃, that is, when T14≤-5℃, the upper fan Fan1 shall be shut down immediately, with a shutdown delay of no more than 1 second, to prevent cold air from entering and aggravating frost formation; (4) When T14 is outside the above range, the upper fan Fan1 maintains the current operating state and does not switch modes; S5. If the upper coil temperature sensor (detecting T14) malfunctions, the unit control system will immediately report fault code Ed1, and the unit will continue to operate without stopping. If the unit has already entered the defrosting state and the effective defrosting time is >60s, the upper fan Fan1 will be turned on at a frequency of 50Hz (P05, parameters have been adjusted according to the model and ambient temperature) for 30s (P06, parameters have been adjusted according to the model and ambient temperature), and then turned off for 30s (60-30). The start-stop operation will be repeated until the unit exits the defrosting state. After exiting the defrosting state, the fault control logic will terminate, and the fan will return to the state before defrosting. S6. The unit in this embodiment has stepless speed regulation function but does not have high and low wind speed function, so the exclusive logic of step S6 is not executed.

[0018] Example 2: Control of a single-wheel dual-supply (dual-system) defrosting fan (see attached) Figure 2 ) In this embodiment, the unit's preset parameters are: P08=0 (dual-supply heating and cooling), P07=0 (water tank temperature probe disabled), indicating a dual-supply system; the system type is a dual system, and the impeller type is a single impeller, suitable for the warm and humid environment of southern winters (ambient temperature 0℃~10℃, relative humidity 70%~90%). Based on this model and ambient temperature, the remaining control parameters are adjusted as follows: P01=3℃, P02=12℃, P03=0 (default, DC fan 1 start logic disabled), P04=25Hz, P05=45Hz, P06=20s (appropriately shortened for warm and humid environments).

[0019] The control process is as follows, with each step executed sequentially: S1. Within 1 second after the unit enters the defrosting state, the control system identifies the system type as dual system and the wind turbine type as single wind turbine. Combined with P08=0 and P07=0, it is determined that the unit is a dual-supply system. At the same time, it is clear that there is no corresponding upper coil temperature for dual-supply systems, and the control logic based on the upper coil temperature is not executed. S2. Since the impeller type is a single impeller, DC fan 1 is turned on. P03=0 (default, already adjusted according to the ambient temperature and humidity in the south). The turn-on logic of DC fan 1 is disabled. Therefore, DC fan 1 remains off. Since there is no corresponding upper coil temperature in the dual system, no subsequent temperature control logic will be executed regardless of the value of P03. S3. The preset parameters have been set and saved by the unit control system. At the same time, the temperature detection module is started to detect the relevant temperature parameters of the dual power supply in real time: Economizer outlet pipe 2 temperature T14 (dual system) and heat exchanger temperature T16 (dual system). The temperature acquisition frequency is real time. S4. Since there is no corresponding upper coil temperature for the dual-system dual-supply, the temperature range control logic of step S4 is not executed, and DC fan 1 remains in the off state. S5. Because the dual-system dual-supply system has no corresponding upper coil temperature, the upper coil temperature sensor fault control logic is not triggered. Even if the sensor is abnormal, the cyclic start-stop operation is not executed, and DC fan 1 remains in the off state. S6. The unit in this embodiment has stepless speed regulation function but does not have high and low wind speed function, so the exclusive logic of step S6 is not executed.

[0020] Example 3: Defrosting fan control for high and low temperature fan units (dual impellers, dual-supply single heating, single system) (see attached) Figure 3 ) In this embodiment, the unit is a high-low fan unit (supporting only high and low speeds, not stepless speed regulation), with preset parameters: P08=3 (dual-supply single heating), P07=0 (water tank temperature probe disabled), indicating dual-supply; the system type is a single system, the fan type is dual fan, adapted to the temperature and humidity environment in central winter (ambient temperature -5℃~8℃, relative humidity 65%~85%). Based on this model and ambient temperature, the remaining control parameters are adjusted as follows: P01=4℃, P02=14℃, P03=8 (adjustment for temperature and humidity environment in central winter), P04=28Hz, P05=48Hz, P06=25s (adjustment for environment in central winter).

[0021] The control process is as follows, with each step executed sequentially: S1. Within 1 second after the unit enters the defrosting state, the control system identifies the system type as a single system and the wind turbine type as a dual wind turbine. Combined with P08=3 and P07=0, it is determined that the unit is a dual-supply unit. At the same time, it is clarified that the coil temperature of the single-system dual-supply unit is T16. S2. Since the wind turbine type is a dual wind turbine, it is determined that the upper fan Fan1 will be turned on, P03=8≠0 (already combined with the central ambient temperature adjustment parameters), and the logic for turning on the upper fan Fan1 will be activated. The subsequent control will be executed according to the logic of step S4. S3. The preset parameters have been set and saved through the unit control system. At the same time, the temperature detection module is started to detect the relevant temperature parameters of the dual power supply in real time: upper coil temperature T16 (single system) and heat exchanger temperature T14 (single system). The temperature acquisition frequency is real time. S4. The temperature acquisition module collects the upper coil temperature T16 in real time. The control system combines the preset parameters P01, P02, and P03 (all of which have been adjusted according to the model and ambient temperature) to determine the mode and control the upper fan Fan1 to run. The logic is the same as in Example 1. S5. If the upper coil temperature sensor (detecting T16) malfunctions, the unit control system will immediately report fault code Ed1, and the unit will continue to operate without stopping. If the unit has already entered defrosting mode and the effective defrosting time is >60s, the upper fan Fan1 will start at a frequency of 48Hz (P05, parameters have been adjusted according to the model and ambient temperature) for 25s (P06, parameters have been adjusted according to the model and ambient temperature), and then shut down for 35s (60-25). The start-stop operation will be repeated until the unit exits the defrosting mode. S6. Execute dedicated logic for high and low voltage fan units to ensure coordinated operation of upper and lower fans: (1) In high wind mode (T16≥14℃), the down fan is turned on through DO4 port and the up fan is turned on through DO16 port. The up and down fans start and stop synchronously and run synchronously to ensure uniform air circulation and speed up defrosting. (2) In low wind mode (14℃-8℃>T16≥4℃, i.e. 4℃≤T16<6℃), the lower fan is turned on through the DO1 port and the upper fan is turned on through the DO15 port. The upper and lower fans start and stop synchronously and run synchronously to reduce energy consumption while ensuring defrosting effect. After the defrosting process is completed, the upper and lower fans will automatically return to their pre-defrosting operating state. If the fans were in the off state before defrosting, they will remain off.

[0022] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art can make various modifications and variations without departing from the spirit and substance of the present invention. For example, they can further optimize the adjustment range of P01-P06 parameters and optimize the temperature acquisition frequency according to different models and ambient temperatures. All such modifications and variations should fall within the protection scope of the present invention.

Claims

1. A method for controlling the operation of a fan during the defrosting process of an air source heat pump unit, characterized in that: The method includes the following steps: S1. After the unit enters the defrosting state, the unit control system first automatically identifies the current system type and rotor type of the unit, and determines the unit type by combining the preset control parameters P08 and P07. The system type includes single system and dual system, and the rotor type includes dual rotor and single rotor. The unit type is determined by the combined use of parameters P08 and P07. The P08 parameter indicates the unit type selection: 0: dual-supply (heating and cooling), 1: tri-supply (heating and cooling), 2: hot water unit, 3: dual-supply (heating only). The P07 parameter indicates whether the water tank temperature probe is enabled or disabled. When P08=0 or 3, P07=0, indicating dual-supply. When P08=2, P07=1, indicating hot water unit. When P08=1, it indicates tri-supply, and the existing tri-supply unit defrost fan control logic applies. The identification process is completed through the unit's preset type identification module and parameter detection module, providing a foundation for the accurate execution of subsequent wind turbine control logic; S2. Based on the identification results of step S1, determine the type of fan to be turned on during the defrosting process: for dual-fan units, turn on the upper fan Fan1; for single-fan units, turn on the DC fan 1. The starting logic of the upper fan Fan1 is controlled by the control parameter P03, which has a value range of [0-20]. When P03=0, the starting logic of the upper fan Fan1 is disabled, meaning that the upper fan Fan1 does not execute any defrosting-related control logic during the defrosting process. The starting logic of the DC fan 1 is also controlled by the control parameter P03, which has a value range of [0-20]. When P03=0, the starting logic of the DC fan 1 is disabled, meaning that during the defrosting process of the single turbine unit, the DC fan 1 does not execute the starting logic by default, and only executes control according to the subsequent logic when P03≠0. P03 needs to have its parameters adjusted according to the current unit model and actual ambient temperature to adapt to the frosting speed and defrosting requirements under different operating conditions. S3. Preset control parameters, including P01, P02, P03, P04, P05, P06, P07, and P08. Each parameter is a digital parameter recognizable by the unit control system. Among them, parameter P07 means enabling or disabling the water tank temperature probe, and parameter P08 means selecting the unit type: 0: dual-supply cooling and heating, 1: triple-supply, 2: hot water unit, 3: dual-supply heating only. P08 and P07 are related: when P08=0 or 3, P07=0; when P08=2, P07=1. P01, P02, P03, P04, P05, and P06 need to be adjusted according to different unit models and actual operating environment temperature. The remaining parameters can be reasonably adjusted according to the actual operating environment and defrosting requirements of the unit, and the adjustments must be saved and taken effect through the unit control system. S4. The upper coil temperature is collected in real time through the unit temperature acquisition module. The upper coil temperature is determined according to parameters P08 and P07 and system type: when P08=0 or 3 and P07=0, i.e., dual-supply, the upper coil temperature of a single system is T16, and there is no corresponding upper coil temperature detection point for dual-system units; when P08=2 and P07=1, i.e., hot water unit, the upper coil temperature of a single system is T14, and there is no corresponding upper coil temperature detection point for dual-system units. The acquisition frequency is real-time to ensure the real-time and accuracy of temperature data. Combined with preset control parameters P01, P02, and P03, the fan operation status is precisely controlled to realize the automatic switching of fan operation mode. If the dual-system unit does not have a corresponding upper coil temperature detection point, the control logic based on the upper coil temperature in this step will not be executed, and the fan will remain in the initial state or the off state. S5. In case of a fault in the upper coil temperature sensor, execute dedicated fault control logic: The unit control system monitors the sensor status in real time. When a fault is detected in the upper coil temperature sensor, fault code Ed1 is immediately reported. At the same time, the unit continues to run without stopping to avoid unit shutdown due to sensor failure and affect user operation. If the unit has entered defrosting mode and the effective defrosting time is >60s, the emergency control logic will be executed immediately: control the upper fan Fan1 to run at frequency P05, or control the DC fan 1 to start through the fixed frequency port DO16, with the starting time strictly P06 seconds, and then shut down for 60-P06 seconds, and repeat the start and stop operation until the unit exits the defrosting mode. After exiting the defrosting mode, the fault control logic will automatically terminate. If there is no corresponding upper coil temperature in the dual system, the fault control logic of this step will not be triggered; P05 and P06 parameters need to be adjusted according to the current model and ambient temperature to avoid energy waste or defrosting interruption in case of fault; S6. For units that only have high and low wind functions, the following dedicated control logic is executed separately to adapt to their fan structure characteristics: In high-wind mode, the down fan is turned on through port DO4 and the up fan is turned on through port DO16. The up and down fans start and stop synchronously. In low-wind mode, the down fan is turned on through port DO1 and the up fan is turned on through port DO15. The up and down fans also start and stop synchronously, ensuring that the up and down fans work together during the defrosting process, improving the uniformity and efficiency of defrosting. In this mode, P01-P03 need to adjust parameters according to the current model and ambient temperature to ensure accurate switching between high and low fan modes.

2. The method for controlling the operation of the fan during the defrosting process of an air source heat pump unit according to claim 1, characterized in that: In step S1, the temperature detection parameters differ for different unit types. The specific detection parameters and requirements are as follows, and the temperature detection parameters must strictly match parameters P08 and P07: When P08=2 and P07=1, it is determined to be a hot water machine: the water tank temperature T16, upper coil temperature, economizer outlet pipe 2 temperature, and heat exchanger temperature need to be monitored in real time; for single-system hot water machines, the upper coil temperature is monitored at the corresponding monitoring point T14, and the economizer outlet pipe 2 temperature is not monitored; for dual-system hot water machines, the upper coil temperature is not monitored, but the economizer outlet pipe 2 temperature is monitored at the corresponding monitoring point T14; the heat exchanger temperature is a fixed value of 25℃, which does not need to be monitored in real time and is preset by the unit control system. When P08=0 or 3 and P07=0, it is determined to be a dual-supply system: no water tank temperature detection is required, but the upper coil temperature, economizer outlet pipe 2 temperature, and heat exchanger temperature must be detected in real time; for a single-system dual-supply system, the upper coil temperature is detected at detection point T16, and the economizer outlet pipe 2 temperature is not detected; for a dual-system dual-supply system, the upper coil temperature is not detected, but the economizer outlet pipe 2 temperature is detected at detection point T14; for the heat exchanger temperature, the single-system dual-supply system corresponds to detection point T14, and the dual-system dual-supply system corresponds to detection point T16. When the heat exchanger temperature detection function is disabled, the heat exchanger temperature is fixed at 25℃, which is preset by the unit control system.

3. The method for controlling the operation of the fan during the defrosting process of an air source heat pump unit according to claim 1, characterized in that: In step S2, the value of P03 is in the range of [0-20], which is a non-negative integer parameter. P03 needs to be adjusted according to different models and actual ambient temperature. When P03≠0, the upper fan Fan1 of the dual-fan turbine unit will be turned on and its operating state will be adjusted according to the logic in step S4 during the defrosting process. The larger the value of P03, the higher the sensitivity of the upper fan Fan1. When P03=0, the upper fan Fan1 of the dual-fan turbine unit will not execute the above control logic during the defrosting process and will always remain in the closed state or the initial state. If there is no corresponding upper coil temperature in the dual system, the upper fan Fan1 will remain in the initial state or the closed state regardless of the value of P03.

4. The method for controlling the operation of the fan during the defrosting process of an air source heat pump unit according to claim 1, characterized in that: In step S4, the operating status of the wind turbine is precisely controlled according to the following logic to achieve automatic switching of the wind turbine operating mode: (1) High wind mode: When the collected upper coil temperature is ≥ P02, control the upper fan Fan1 to run stably at frequency P05, or control the DC fan 1 to start stably through the fixed frequency port DO16; the frequency fluctuation range of the upper fan Fan1 shall not exceed ±1Hz, and the speed of the DC fan 1 shall remain constant after it is turned on to ensure the defrosting efficiency in high wind mode; P02 and P05 need to be adjusted according to the current model and ambient temperature to adapt to different frosting speeds; (2) Low wind mode: When P02-P03 > the collected upper coil temperature ≥ P01, control the upper fan Fan1 to run stably at frequency P04, or control the DC fan 1 to start stably through the fixed frequency port DO15; in this mode, the fan operating power is lower than that in high wind mode, and energy consumption is reduced to the maximum extent while ensuring the defrosting effect; P01, P03, and P04 need to be adjusted according to the current model and ambient temperature to balance the defrosting effect and energy consumption; (3) Shutdown mode: When the collected upper coil temperature is ≤ P01-P03, control the upper fan Fan1 to shut down immediately, or control the fixed frequency ports DO16 and DO15 of DC fan 1 to shut down immediately; the shutdown action delay shall not exceed 1 second to avoid cold air from continuously entering the unit and causing frosting to intensify; P01 and P03 need to be adjusted according to the current model and ambient temperature to avoid incomplete defrosting or ineffective fan shutdown; (4) Original mode: When the above conditions (1), (2) and (3) are not met, the fan maintains the current operating state and does not switch modes, so as to avoid the instability of unit operation caused by frequent switching of operating modes and reduce the start-up and shutdown losses of the fan.

5. The method for controlling the operation of the fan during the defrosting process of an air source heat pump unit according to claim 1 or 4, characterized in that: In step S4, the fixed-frequency control of DC fan 1 is only executed in a single turbine unit. When P03≠0, DC fan 1 is turned on and switches operating ports according to the logic of step S4, with a port switching delay of no more than 0.5 seconds. When P03=0, DC fan 1 does not execute the above control logic during defrosting and remains in the off state by default, and is not affected by changes in the upper coil temperature. If there is no corresponding upper coil temperature in the dual system, DC fan 1 will maintain the initial state or the off state regardless of the value of P03. P01, P02, P03, P04, and P05 need to be adjusted according to the current model and ambient temperature to ensure that the control logic is adapted to the current operating conditions.

6. The method for controlling the operation of the fan during the defrosting process of an air source heat pump unit according to claim 1, characterized in that: In step S5, the fault control logic is triggered only when the upper coil temperature sensor fails and the unit has a corresponding upper coil temperature detection, i.e., a single system dual supply, a single system hot water machine, and the fault detection adopts a dual verification mechanism to ensure accurate fault judgment and avoid false alarms. The cycle of the cyclic start-stop operation is fixed at 60 seconds. The start time is set by P06, and the value of P06 is in the range of [10-50] seconds. P06 needs to be adjusted according to different models and actual ambient temperature. The stop time is the difference between 60 seconds and P06. The cyclic operation continues until the unit exits the defrost state. At this time, the fault control logic will automatically terminate, and the unit will continue to report fault code Ed1 until the sensor fault is resolved.

7. The method for controlling the operation of the fan during the defrosting process of an air source heat pump unit according to claim 1, characterized in that: In step S6, the upper and lower fan activation logic of the high and low fan units only applies to the defrosting process and corresponds one-to-one with the high and low fan modes in step S4. The activation state of the lower fan switches synchronously with the upper fan, with a switching delay of no more than 1 second. After the defrosting process is completed, the upper and lower fans automatically return to their pre-defrosting operating states. If the fans were in the off state before defrosting, they remain off after defrosting. If there is no corresponding upper coil temperature in the dual system, the high and low fan units maintain their initial operating states. The parameters of P01-P03 corresponding to the high and low fan units need to be adjusted according to the model and ambient temperature to ensure the coordinated operation of the upper and lower fans.

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