CN115523745B - Heat pump dryer control method and device, heat pump dryer and storage medium - Google Patents

Abstract

The invention provides a heat pump dryer control method, device, heat pump dryer and storage medium, including: when the heat pump dryer is heating, based on the temperature difference between the target setting temperature and the return air outlet temperature, controlling the compressor Run, and control the heating device to start and stop to adjust the return air outlet temperature rise; when it is determined that the absolute value of the temperature difference is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target period, control all The heat pump dryer stops heating. The present invention can accurately determine the drying state of an object, thereby finely controlling the compressor and heating device according to different drying states to achieve the purpose of accurately controlling the dryness of the object to be dried. While improving the drying efficiency, it also reduces the risk of drying. Reduce system energy consumption and improve system energy conservation and emission reduction efficiency.

Description

Heat pump dryer control method, device, heat pump dryer and storage medium

Technical field

The present invention relates to the technical field of heat pump dryers, and in particular to a heat pump dryer control method, device, heat pump dryer and storage medium.

Background technique

At present, heat pump dryers are widely used in various fields, including chemical industry, medicine, products, wood, agricultural and sideline products, etc., with the advantages of safety, environmental protection, energy saving and high efficiency.

The heat pump dryer uses the condensation heat of the air conditioner to heat and dehumidify objects. During heating, the refrigerant continuously repeats the thermodynamic cycle process of evaporation, compression, condensation, throttling and re-evaporation in the system. At the same time, the heat released during the thermodynamic cycle is continuously transferred to the drying chamber. , to achieve continuous drying of objects in the drying room. However, the existing control method is too simple and rough, and it is difficult to accurately judge whether the dryness of the object to be heated and dehumidified meets the requirements. The drying efficiency is poor and the energy consumption is high.

Therefore, how to better control the heat pump dryer has become an urgent technical problem that needs to be solved in the industry.

Contents of the invention

The invention provides a heat pump dryer control method, device, heat pump dryer and storage medium to better control the heat pump dryer, improve drying efficiency and reduce energy consumption.

The invention provides a heat pump dryer control method, which includes:

When the heat pump dryer is heating, based on the temperature difference between the target set temperature and the return air outlet temperature, the compressor operation is controlled, and the heating device is controlled to start and stop to adjust the return air outlet temperature increase;

When it is determined that the absolute value of the temperature difference is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target time period, the heat pump dryer is controlled to stop heating.

According to a heat pump dryer control method provided by the present invention, controlling the operation of the compressor and controlling the start and stop of the heating device based on the temperature difference between the target set temperature and the return air outlet temperature includes:

When the temperature difference between the target set temperature and the return air outlet temperature is greater than the first threshold, the heating device is controlled to start and the compressor is controlled to operate at the maximum operating frequency.

According to a heat pump dryer control method provided by the present invention, the method further includes:

When the temperature difference between the target set temperature and the return air outlet temperature is greater than the second threshold and not greater than the first threshold, the heating device is controlled to stop operating, and the compressor is controlled to operate at the maximum operating frequency. .

According to a heat pump dryer control method provided by the present invention, the method further includes:

When the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than a second threshold, the compressor is controlled to operate based on a first operating frequency and a first control mode, and the first operating frequency It is obtained based on the maximum operating frequency of the compressor minus the first frequency threshold.

According to a heat pump dryer control method provided by the present invention, controlling the compressor to operate based on a first operating frequency and a first control mode includes:

In the case where the change trend of the return air outlet temperature is gradually increasing during the previous operating cycle, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle during the current operating cycle; wherein, in When the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, the operating frequency corresponding to the corresponding first operating cycle is the first operating frequency;

In the case that the change trend of the return air inlet temperature is not gradually increasing in the previous operating cycle, the compressor is controlled to operate based on the second operating frequency in the current operating cycle, and the second operating frequency is It is obtained by adding the second frequency threshold based on the operating frequency corresponding to the previous operating cycle.

According to a heat pump dryer control method provided by the present invention, the method further includes:

When the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, the compressor is controlled to operate based on the current operating frequency and the second control mode, and the current operating frequency is based on the previous operating cycle. The corresponding operating frequency is obtained by subtracting the third frequency threshold.

According to a heat pump dryer control method provided by the present invention, the control of the compressor to operate based on the current operating frequency and the second control mode includes:

In the case that the change trend of the return air inlet temperature is gradually increasing in the previous operating cycle, the compressor is controlled to operate based on the third operating frequency in the current operating cycle, and the third operating frequency is based on The operating frequency corresponding to the previous operating cycle is obtained by subtracting the fourth frequency threshold; wherein, when the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, the corresponding first operating cycle corresponds to The operating frequency is the current operating frequency;

In the case where the change trend of the return air inlet temperature does not gradually increase during the previous operating cycle, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle during the current operating cycle.

The invention also provides a heat pump dryer control device, which includes:

The first control module is used to control the operation of the compressor based on the temperature difference between the target setting temperature and the return air outlet temperature when the heat pump dryer is heating, and to control the start and stop of the heating device to adjust the temperature rise of the return air outlet. high;

The second control module is used to control the heat pump dryer to stop heating when it is determined that the absolute value of the temperature difference is less than the target temperature threshold and the return air outlet humidity continues to be less than the target humidity threshold within the target time period.

The invention also provides a heat pump dryer, including:

Dryer body, evaporator, compressor, condenser, dehumidifier, fresh air valve, air outlet fan and heating device;

The evaporator, the compressor, the condenser, the dehumidifier, the fresh air valve, the air outlet fan and the heating device are all arranged in the dryer body, and the heating device Disposed between the condenser and the air outlet fan;

Also included: controller, temperature sensor and humidity sensor;

The heating device, the temperature sensor and the humidity sensor are all electrically connected to the controller; the temperature sensor and the humidity sensor are arranged at the return air outlet; the temperature sensor is used to obtain the return air outlet Temperature, the humidity sensor is used to obtain the humidity of the return air outlet;

Wherein, the controller includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, any one of the heat pump drying methods described above is implemented. Dryer control methods.

The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it implements any one of the above heat pump dryer control methods.

The present invention also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the computer program implements any one of the above heat pump dryer control methods.

The heat pump dryer control method, device, heat pump dryer and storage medium provided by the present invention, by adding a temperature sensor and a humidity sensor to the return air outlet, set the temperature and detection based on the target when the heat pump dryer is heating. The temperature difference of the return air outlet temperature is reached, and the operation of the compressor is carefully controlled. By adding a heating device, controlling the start and stop of the heating device for auxiliary heat, and adjusting the rising rate of the return air outlet temperature, it is beneficial to improve the drying efficiency; When it is determined that the absolute value of the temperature difference between the target set temperature and the return air outlet temperature is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target duration, it can be accurately determined that the object has been dried, and then the heat pump drying can be controlled The machine stops heating. By detecting the return air outlet temperature and return air outlet humidity in real time, the drying status of the object can be accurately judged, so that the compressor and heating device can be precisely controlled according to different drying statuses to achieve the purpose of accurately controlling the dryness of the objects to be dried. While improving drying efficiency, it also reduces system energy consumption and improves the efficiency of system energy conservation and emission reduction.

Description of the drawings

In order to explain the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are of the present invention. For some embodiments of the invention, those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic system structure diagram of the heat pump dryer provided by the present invention;

Figure 2 is a schematic flow chart of the heat pump dryer control method provided by the present invention;

Figure 3 is a schematic structural diagram of the heat pump dryer control device provided by the present invention;

Figure 4 is a schematic structural diagram of the controller in the heat pump dryer provided by the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention. , not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

In the description of the invention, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrally connected; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

The heat pump dryer control method, device, heat pump dryer and storage medium of the present invention will be described below with reference to Figures 1-4.

Figure 1 is a schematic system structure diagram of a heat pump dryer provided by the present invention. As shown in Figure 1, the heat pump dryer includes a dryer body 1, an evaporator 11, a compressor 12, a condenser 13, and a dehumidifier 14. , fresh air valve 15, air outlet fan 16 and heating device 17 at the air outlet 100;

The evaporator 11, the compressor 12, the condenser 13, the dehumidifier 14, the fresh air valve 15, the air outlet fan 16 and the heating device 17 are all arranged in the dryer body 1, and the heating device 17 is arranged in the condenser 13 and the air outlet fan. between 16;

The heat pump dryer also includes: a controller, a temperature sensor 18 and a humidity sensor 19; the heating device 17, the temperature sensor 18 and the humidity sensor 19 are all electrically connected to the controller; the temperature sensor 18 and the humidity sensor 19 are both arranged in the return air outlet 200 at; the temperature sensor is used to obtain the return air outlet temperature, and the humidity sensor is used to obtain the return air outlet humidity;

As shown in Figure 1, one end of the evaporator 11 (outdoor unit) is connected to one end of the compressor 12, the other end of the compressor 12 is connected to one end of the condenser 13 (internal unit), and the other end of the evaporator 11 expands electronically The valve is connected to the other end of the condenser 13; one end of the dehumidifier 14 is connected to the other end of the condenser 13 through an electronic expansion valve, and the other end of the dehumidifier 14 is connected to one end of the evaporator 11 and one end of the compressor 12. Therefore, when the heat pump dryer is heating, the refrigerant can continuously repeat the thermodynamic cycle process of evaporation, compression, condensation, throttling and re-evaporation in the drying system. At the same time, the heat released during the thermodynamic cycle is It is continuously transferred to the drying room to realize continuous heating and dehumidification of the objects in the drying room until they are dried.

Figure 2 is a schematic flowchart of the heat pump dryer control method provided by the present invention. As shown in Figure 2, it includes: step 110 and step 120.

Step 110, when the heat pump dryer is heating, based on the temperature difference between the target set temperature and the return air outlet temperature, control the operation of the compressor and control the start and stop of the heating device to adjust the increase in the return air outlet temperature;

Specifically, the target setting temperature described in the embodiment of the present invention refers to the preset drying temperature, which may be the system's default setting temperature, or the temperature set by the user according to actual needs.

The return air outlet temperature described in the embodiment of the present invention refers to the temperature information at the return air outlet of the drying area collected in real time through a temperature sensor installed at the return air outlet.

The heating device described in the embodiment of the present invention may be an electric heating device, a solar heating device, or other forms of heating device, which the present invention does not specifically limit.

In embodiments of the present invention, by adding a heating device, the heating device can be turned on when the temperature difference between the target set temperature and the return air outlet temperature is too large, thereby increasing the heat released into the drying chamber and effectively improving the drying area. Drying efficiency of medium objects.

Further, in the embodiment of the present invention, when the heat pump dryer is heating, the operation of the compressor is finely controlled based on the temperature difference between the target set temperature and the return air outlet temperature, and the heating device is controlled. It starts when the temperature difference is large and stops when the temperature difference is small. This adjusts the temperature rise of the return air outlet, increases the drying intensity of objects in the drying area, speeds up the drying of objects, and improves the drying speed. While improving efficiency, it ensures the effect of energy saving and emission reduction.

Step 120: When it is determined that the absolute value of the temperature difference between the target set temperature and the return air outlet temperature is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target time period, control the heat pump dryer to stop heating.

Specifically, the target temperature threshold described in the embodiment of the present invention refers to a preset temperature threshold, which can be flexibly set according to actual design requirements. For example, the target temperature threshold can range from 1°C to 3°C.

The target duration described in the embodiment of the present invention refers to a preset duration threshold, which may be the default duration threshold of the drying system, or may be a duration threshold set by the user according to actual needs. Its value range can be from 2 minutes to 5 minutes. Optionally, in this embodiment of the present invention, the target duration may be 3 minutes.

The target humidity threshold described in the embodiment of the present invention refers to a preset humidity threshold, which can be used to determine whether the object in the drying zone has been dried. It can be the default humidity threshold of the drying system, or it can be the humidity threshold set by the user based on the material properties of the object to be dried. Generally, the target humidity threshold can be 30%.

Further, in the embodiment of the present invention, by detecting the return air outlet temperature and return air outlet humidity, it is determined that the absolute value of the temperature difference between the target set temperature and the return air outlet temperature is less than the target temperature threshold, and the return air outlet humidity continues to be less than In the case of the target humidity threshold, it can be seen that the humidity of the objects in the drying area has been effectively reduced, the dryness has reached the requirements, and the objects have been dried, then the heat pump dryer can be controlled to stop heating.

Optionally, in a specific embodiment, the target temperature threshold may be 2°C. When the absolute value of the temperature difference between the target set temperature TC _m and the return air outlet temperature TC is less than 2°C, that is, -2°C ≤ TC _m -TC ≤ 2°C, the return air outlet humidity can be judged at this time. During the continuous target duration, If within 3 minutes, it is detected that the return air outlet humidity of the drying area continues to be less than 30%, it means that the object to be dried has been dried, and the dryer heating can be stopped.

The heat pump dryer control method of the embodiment of the present invention adds a temperature sensor and a humidity sensor to the return air outlet, and when the heat pump dryer is heating, based on the temperature difference between the target set temperature and the detected return air outlet temperature, The operation of the compressor is carefully controlled, and by adding a heating device, controlling the start and stop of the heating device for auxiliary heating, and adjusting the rising rate of the return air outlet temperature, which is beneficial to improving the drying efficiency; after determining the target setting temperature and the return air outlet temperature If the absolute value of the temperature difference is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target time, it can be accurately determined that the object has been dried, and the heat pump dryer can be controlled to stop heating. By detecting the return air outlet temperature and return air outlet humidity in real time, the drying status of the object can be accurately judged, so that the compressor and heating device can be precisely controlled according to different drying statuses to achieve the purpose of accurately controlling the dryness of the objects to be dried. While improving drying efficiency, it also reduces system energy consumption and improves the efficiency of system energy conservation and emission reduction.

Based on the contents of the above embodiments, as an optional embodiment, in step 110, based on the temperature difference between the target set temperature and the return air outlet temperature, the operation of the compressor is controlled and the heating device is started and stopped, including:

When the temperature difference between the target set temperature and the return air outlet temperature is greater than the first threshold, the heating device is controlled to start and the compressor is controlled to run at the maximum operating frequency.

Specifically, the first threshold described in the embodiment of the present invention refers to the preset temperature difference threshold, which can be characterized as the threshold when the temperature difference between the target set temperature and the return air outlet temperature is too large, and its value range can be 19 ℃ to 21℃.

It can be understood that the maximum operating frequency refers to the maximum frequency at which the compressor can operate, which can be determined by the actual capacity and model of the heat pump dryer.

In the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air outlet temperature is greater than the first threshold, it means that the temperature difference between the target set temperature and the return air outlet temperature is too large at this time, and the return air outlet temperature is far less than At the target setting temperature, the temperature in the drying zone is too low and requires high-intensity heating. At this time, the compressor can be controlled to run at the maximum operating frequency and the heating device can be controlled to start heating.

Alternatively, in a specific embodiment, assuming that the target set temperature is expressed as TC _m and the return air outlet temperature is expressed as TC, the first threshold can take a value of 20°C, that is, when it is determined that TC _m -TC> At 20°C, the heating device can be controlled to start and the compressor can be controlled to run at the maximum operating frequency.

According to the method of the embodiment of the present invention, by adding a heating device, when the return air outlet temperature is far lower than the target set temperature, the heating device is automatically started to release heat, and at the same time, the compressor is controlled to run at the maximum operating frequency, so that the drying area can be effectively controlled. The rapid heating is helpful to improve the drying efficiency of the system.

Based on the contents of the above embodiments, as an optional embodiment, the method further includes: controlling the heating device to stop when the temperature difference between the target set temperature and the return air outlet temperature is greater than the second threshold and not greater than the first threshold. operation, and control the compressor to run at the maximum operating frequency.

Specifically, the second threshold described in the embodiment of the present invention refers to a preset temperature difference threshold, and its value range may be 9°C to 11°C. It can indicate that the target setting temperature and the return air outlet temperature are at a relatively close level. Optionally, in the embodiment of the present invention, the second threshold value may be 10°C.

In the embodiment of the present invention, when the temperature difference between the target set temperature and the return air outlet temperature is greater than the first threshold, the heating device is controlled to start and the compressor is controlled to operate at the maximum operating frequency. As the return air outlet temperature continues to rise, the temperature difference between the target set temperature and the return air outlet temperature gradually decreases. If it is determined that the temperature difference between the target set temperature and the return air outlet temperature is greater than the second threshold and not greater than the first threshold, it means that the drying zone When the return air temperature is relatively close to the target set temperature, the heating device can be controlled to stop running and the compressor can be controlled to maintain the maximum operating frequency.

Alternatively, in a specific embodiment, the second threshold may be 10°C, and the first threshold may be 20°C, when the temperature difference between the target set temperature TC _m and the return air outlet temperature TC satisfies 10°C < TC _m -TC ≤ 20℃, the heating device can be controlled to stop running and the compressor can be controlled to run at the maximum operating frequency.

According to the method of the embodiment of the present invention, when the temperature difference between the target set temperature and the return air outlet temperature is greater than the second threshold and not greater than the first threshold, the heating device is controlled to stop operating and the compressor is controlled to operate at the maximum operating frequency, while ensuring While improving the drying efficiency of the system, it can effectively reduce the energy consumption of the system.

Based on the content of the above embodiment, as an optional embodiment, the method further includes: when the temperature difference between the target set temperature and the return air inlet temperature is greater than zero and not greater than the second threshold, controlling the compressor based on the first The operating frequency and the first control mode operation, the first operating frequency is obtained based on the maximum operating frequency of the compressor minus the first frequency threshold.

Specifically, the first frequency threshold described in the embodiment of the present invention refers to a preset frequency threshold, which can be flexibly set according to actual design requirements. For example, the first frequency threshold can range from 4 Hz to 6 Hz.

The first operating frequency described in the embodiment of the present invention is obtained based on the maximum operating frequency of the compressor minus the first frequency threshold. That is to say, if the first frequency threshold is 5Hz, then the first operating frequency f ₁ = fmax-5, where fmax represents the maximum operating frequency of the compressor.

The first control mode described in the embodiment of the present invention refers to a control mode that adjusts the operating frequency of the compressor based on the change trend of the return air inlet temperature, which can be represented by intermittently increasing the operating frequency of the compressor.

Further, in the embodiment of the present invention, when the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, it means that the target set temperature and the return air outlet temperature are relatively close. level, the compressor can be controlled to operate in the first control mode based on the first operating frequency as the initial operating frequency of the compressor, thereby achieving fine control of the compressor in the heat pump dryer.

In the method of the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, that is, it is determined that the target set temperature and the return air outlet temperature are at a relatively close level, by calling the third One control mode enables fine control of the compressor and improves the drying efficiency of the system.

Based on the contents of the above embodiments, as an optional embodiment, controlling the compressor to operate based on the first operating frequency and the first control mode includes:

In the previous operating cycle, when the change trend of the return air inlet temperature is gradually increasing, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle in the current operating cycle; where, at the target set temperature When the temperature difference from the return air outlet temperature is greater than zero and not greater than the second threshold, the operating frequency corresponding to the corresponding first operating cycle is the first operating frequency;

In the case where the change trend of the return air inlet temperature does not gradually increase during the previous operating cycle, the compressor is controlled to operate based on the second operating frequency during the current operating cycle, and the second operating frequency is based on the previous operating cycle. The corresponding operating frequency is obtained by adding the second frequency threshold.

Specifically, the operating cycle described in the embodiment of the present invention refers to the preset compressor operating cycle, which can be designed according to actual needs. For example, every 1 minute can be set as an operating cycle, or every 2 minutes can be set. for one operating cycle.

The second frequency threshold described in the embodiment of the present invention refers to a preset frequency threshold, and its specific value can be flexibly set according to actual needs. For example, the value range of the second frequency threshold can be 1 Hz to 3 Hz.

The second operating frequency described in the embodiment of the present invention is obtained by adding the second frequency threshold based on the operating frequency corresponding to the previous operating cycle. That is to say, assuming that the second frequency threshold can take a value of 1 Hz, then the second operating frequency f ₂ =f+1, where f represents the operating frequency of the compressor in the previous operating cycle.

In the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, that is, when the target set temperature and the return air outlet temperature are at a relatively close level, by pre-setting the compressor The operating time is divided into operating cycles, and the changing trend of the return air inlet temperature is detected during each operating cycle of the compressor, so that the operation of the compressor can be finely controlled based on the changing trend of the return air inlet temperature during each operating cycle.

It should be noted that when the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, the operating frequency corresponding to the corresponding first operating cycle is the first operating frequency, that is, in In the first operating cycle, the compressor operates at the first operating frequency.

Further, in the embodiment of the present invention, the changing trend of the return air inlet temperature is detected during each operating cycle of the compressor. If the changing trend of the return air inlet temperature is gradually increasing in the previous operating cycle, , then the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle during the current operating cycle. For example, when it is determined that the change trend of the return air outlet temperature in the first operating cycle is to gradually increase, it can be determined that the compressor is controlled to maintain the first operating frequency in the second operating cycle.

If the change trend of the return air inlet temperature does not gradually increase in the previous operating cycle, the compressor is controlled to operate based on the second operating frequency in the current operating cycle. For example, when it is determined that the change trend of the return air inlet temperature in the first operating cycle is not to gradually increase, it can be determined that in the second operating cycle, the compressor is controlled to operate based on the second operating frequency. At this time, the second operating frequency is The first operating frequency plus the second frequency threshold.

By analogy, according to the above method, it can be determined that when the temperature difference between the target set temperature and the return air inlet temperature is greater than zero and not greater than the second threshold, the compressor will operate in the third operating cycle, the fourth operating cycle, and the second threshold. The operating frequency within multiple consecutive cycles such as five operating cycles.

In the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, the change trend of the return air outlet temperature is determined during each operating cycle of the compressor. , the operating frequency of the compressor in each operating cycle can be determined, and the compressor can be finely controlled until the temperature difference between the target set temperature and the return air outlet temperature is no greater than zero.

Optionally, in a specific embodiment of the present invention, the second threshold can be 10°C, the first frequency threshold can be 5Hz, the first operating frequency f ₁ =fmax-5, the second frequency threshold can be The value is 1Hz, then when the temperature difference between the target set temperature TCm and the return air outlet temperature TC satisfies 0<TCm-TC≤10℃, the compressor is first controlled to use the first operating frequency f ₁ =f _max -5 as the initial operating frequency. After running, every 1 minute is regarded as one operating cycle of the compressor, and the temperature change trend of TC is judged. Assume that the temperature change of TC Δt=t ₁ -t ₀ , t ₁ represents the return air outlet temperature at the end of 1 minute of operating cycle. , t ₀ represents the return air outlet temperature at the beginning of 1 minute;

If Δt>0, it means that the change trend of the return air outlet temperature is gradually increasing. At this time, the compressor will be controlled to maintain the corresponding operating frequency in the previous operating cycle during the current operating cycle;

If Δt≤0, it means that the change trend of the return air inlet temperature is not gradually increasing, and the compressor is controlled to run at the second operating frequency f ₂ =f+1 in the current operating cycle, where f represents the previous operating cycle. corresponding operating frequency.

The method of the embodiment of the present invention determines that the temperature difference between the target set temperature and the return air outlet temperature is greater than zero and not greater than the second threshold, that is, when it is determined that the target set temperature and the return air outlet temperature are at a relatively close level, during the operation cycle Continuously detect the changing trend of the return air inlet temperature, and gradually increase the operating frequency of the compressor based on the changing trend of the return air inlet temperature to achieve fine adjustment of the compressor operating frequency, which can effectively improve the drying efficiency of the system and reduce the energy consumption of the system. .

Based on the contents of the above embodiments, as an optional embodiment, the method further includes:

When the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, the compressor is controlled to operate based on the current operating frequency and the second control mode. The current operating frequency is based on the operating frequency corresponding to the previous operating cycle minus the third The frequency threshold is obtained.

Specifically, the current operating frequency described in the embodiment of the present invention refers to the operating frequency of the compressor when the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero.

It can be understood that the previous operating cycle at this time refers to the previous operating cycle at the time when the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, which can also be understood as the target in the above embodiment. When the temperature difference between the set temperature and the return air inlet temperature is greater than zero and not greater than the second threshold, the last operating cycle of the divided compressor operating cycles.

The third frequency threshold described in the embodiment of the present invention refers to a preset frequency threshold, which can be flexibly set according to actual design requirements. For example, the third frequency threshold can range from 1 Hz to 3 Hz.

The current operating frequency described in the embodiment of the present invention is obtained based on the operating frequency corresponding to the previous operating cycle minus the third frequency threshold. That is to say, if the third frequency threshold is 2 Hz, then the current operating frequency F = f ₀ -2, where f ₀ represents the operating frequency corresponding to the previous operating cycle, that is, the operating frequency corresponding to the previous operating cycle at the moment when the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero.

The second control mode described in the embodiment of the present invention is also a control mode that adjusts the operating frequency of the compressor based on the change trend of the return air inlet temperature, which can be manifested as intermittently reducing the operating frequency of the compressor.

Further, in the embodiment of the present invention, when the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, it means that the target set temperature is the same as the return air outlet temperature of the drying room, or the return air outlet temperature If the temperature is higher than the target setting temperature, the compressor can be controlled to operate in the second control mode based on the current operating frequency as the initial operating frequency of the compressor, to further finely control the compressor in the heat pump dryer.

According to the method of the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, that is, it is determined that the return air outlet temperature in the drying room has reached or exceeded the target set temperature, by calling the second control mode, Achieve fine control of the compressor and improve the drying efficiency of the system.

Based on the contents of the above embodiments, as an optional embodiment, controlling the compressor to operate based on the current operating frequency and the second control mode includes:

In the case where the change trend of the return air inlet temperature is gradually increasing during the previous operating cycle, the compressor is controlled to operate based on the third operating frequency during the current operating cycle. The third operating frequency is based on the previous operating cycle. It is obtained by subtracting the fourth frequency threshold from the operating frequency; where, when the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, the operating frequency corresponding to the corresponding first operating cycle is the current operating frequency;

In the case where the change trend of the return air inlet temperature does not gradually increase during the previous operating cycle, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle during the current operating cycle.

Specifically, the fourth frequency threshold described in the embodiment of the present invention refers to a preset frequency threshold, and its specific value can be flexibly set according to actual needs. For example, the fourth frequency threshold can range from 1 Hz to 3 Hz.

The third operating frequency described in the embodiment of the present invention is obtained based on the operating frequency corresponding to the previous operating cycle minus the fourth frequency threshold. That is to say, assuming that the fourth frequency threshold can take a value of 2Hz, then the third operating frequency Frequency f ₃ =f-2, where f represents the operating frequency of the compressor in the previous operating cycle.

In the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero, that is, when the return air inlet temperature has reached or exceeded the target set temperature, it can also be determined by measuring the temperature on each operating cycle of the compressor. Detect the changing trend of the return air inlet temperature, and finely control the operation of the compressor based on the changing trend of the return air inlet temperature in each operating cycle.

It should be noted that when the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, the operating frequency corresponding to the first operating cycle is the current operating frequency. That is to say, at this time, during the first operating period Periodically, the compressor operates at the current operating frequency mentioned above, that is, the operating frequency of the compressor when the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero.

Further, in the embodiment of the present invention, when the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero, the change trend of the return air inlet temperature is detected during each operating cycle of the compressor. If the temperature difference in the previous operation cycle is During the operating cycle, when the change trend of the return air inlet temperature is gradually increasing, the compressor is controlled to operate based on the third operating frequency during the current operating cycle.

For example, when it is determined that the change trend of the return air outlet temperature in the first operating cycle is to gradually increase, it can be determined that the compressor is controlled to run at the third operating frequency in the second operating cycle. At this time, the third operating frequency is the above The current operating frequency minus the fourth frequency threshold.

If the change trend of the return air inlet temperature does not gradually increase during the previous operating cycle, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle during the current operating cycle. For example, when it is determined that the change trend of the return air outlet temperature in the first operating cycle is not to gradually increase, it can be determined that in the second operating cycle, the compressor is controlled to maintain the corresponding operating frequency in the first operating cycle, that is, in the second operating cycle During the two operating cycles, the compressor is controlled to maintain the above current operating frequency.

By analogy, according to the above method, it can be determined that when the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero, the compressor will operate in the third, fourth, and fifth operating cycles. Wait for the operating frequency within multiple consecutive cycles.

Optionally, in a specific embodiment of the present invention, the value of the third frequency threshold may be 2 Hz, the value of the fourth frequency threshold may be 2 Hz, and the third operating frequency f ₃ =f-2, f represents compression. The operating frequency of the machine in the previous operating cycle, the current operating frequency F = f ₀ -2, then when the temperature difference between the target set temperature TC _m and the return air outlet temperature TC satisfies TC _m -TC ≤ 0, first control The compressor runs with the above current operating frequency F as the initial operating frequency. After that, every 1 minute is an operating cycle of the compressor to judge the temperature change trend of TC. The temperature change of TC is Δt=t ₁ -t ₀ , t ₁ represents the return air outlet temperature at the end of 1 minute of the operation cycle, t ₀ represents the return air outlet temperature at the beginning of 1 minute;

If Δt>0, it means that the change trend of the return air inlet temperature is gradually increasing. At this time, the compressor will be controlled to operate according to the third operating frequency f ₃ = f-2 during the current operating cycle;

If Δt≤0, it means that the change trend of the return air inlet temperature is not gradually increasing. At this time, the current operating cycle will control the compressor to maintain the corresponding operating frequency in the previous operating cycle.

In the method of the embodiment of the present invention, when it is determined that the temperature difference between the target set temperature and the return air outlet temperature is not greater than zero, that is, when it is determined that the return air outlet temperature reaches or exceeds the target set temperature, the return air outlet temperature is continuously detected during the operation cycle of the compressor. According to the changing trend of the return air inlet temperature, gradually reduce the operating frequency of the compressor to prevent the return air inlet temperature from being too high, reduce energy consumption, and achieve fine adjustment of the compressor operating frequency, which can further improve the drying of the system. efficiency and reduce system operation energy consumption.

In a specific embodiment of the present invention, the temperature and humidity parameters of the return air outlet of the drying area are the return air outlet temperature TC and the return air outlet humidity RH as the control targets. The target setting temperature can be set to TCm, and the target humidity threshold can be 30%. The heating device adopts electric heating device;

When it is determined that TCm-TC>20℃, turn on the electric heating device and control the operating frequency of the compressor f = fmax, that is, run at the maximum operating frequency;

When it is determined that 10℃＜TC _m -TC≤20℃, turn off the electric heating device and control the compressor to operate at the maximum operating frequency f=fmax;

When it is determined that 0＜TC _m -TC≤10°C, the compressor is controlled to run at the first operating frequency f ₁ =f _max -5, and then the temperature of TC is determined at a cycle interval of every 1 minute. For the changing trend, assume Δt=t ₁ -t ₀ , t ₁ represents the return air outlet temperature at the end of 1 minute within a periodic time interval, and t ₀ represents the return air outlet temperature at the beginning of 1 minute;

If Δt>0, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle unchanged;

If Δt≤0, increase the operating frequency of the compressor at this time and control the compressor to operate at the second operating frequency f ₂ =f+1, where f represents the operating frequency corresponding to the previous operating cycle;

When TC _m -TC ≤ 0 is determined, the compressor is controlled to run at the current operating frequency F = f0-2. After that, every 1 minute is used as a cycle time interval to judge the temperature change trend of TC, assuming Δt = t ₁ -t ₀ , t ₁ represents the return air outlet temperature at the end of 1 minute within a cycle time interval, t ₀ represents the return air outlet temperature at the beginning of 1 minute;

If Δt>0, continue to lower the frequency of the compressor and control the compressor to operate at the third operating frequency f ₃ =f-2, where f represents the operating frequency corresponding to the previous operating cycle;

If Δt≤0, the compressor is controlled to maintain the operating frequency corresponding to the previous operating cycle unchanged.

When it is determined that -2℃≤TCm-TC≤2℃, start to judge the return air humidity. If RH<30% is detected for 3 minutes, it means that the object to be dried has been dried and the heat pump compressor can be controlled. Stop heating.

The heat pump dryer control device provided by the present invention will be described below. The heat pump dryer control device described below and the heat pump dryer control method described above can be referenced correspondingly.

Figure 3 is a schematic structural diagram of the heat pump dryer control device provided by the present invention. As shown in Figure 3, it includes:

The first control module 310 is used to control the operation of the compressor based on the temperature difference between the target setting temperature and the return air outlet temperature when the heat pump dryer is heating, and to control the start and stop of the heating device to adjust the return air outlet temperature. rise; rise

The second control module 320 is used to control the heat pump dryer to stop heating when it is determined that the absolute value of the temperature difference is less than the target temperature threshold and the return air outlet humidity continues to be less than the target humidity threshold within the target time period.

The heat pump dryer control device described in this embodiment can be used to execute the above heat pump dryer control method embodiment. Its principles and technical effects are similar and will not be described again here.

The heat pump dryer control device in the embodiment of the present invention adds a temperature sensor and a humidity sensor to the return air outlet, and when the heat pump dryer is heating, based on the temperature difference between the target setting temperature and the detected return air outlet temperature, the control device The operation of the compressor is carefully controlled, and by adding a heating device, controlling the start and stop of the heating device for auxiliary heating, and adjusting the rising rate of the return air outlet temperature, which is beneficial to improving the drying efficiency; after determining the target setting temperature and the return air outlet temperature If the absolute value of the temperature difference is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target time, it can be accurately determined that the object has been dried, and the heat pump dryer can be controlled to stop heating. By detecting the return air outlet temperature and return air outlet humidity in real time, the drying status of the object can be accurately judged, so that the compressor and heating device can be precisely controlled according to different drying statuses to achieve the purpose of accurately controlling the dryness of the objects to be dried. While improving drying efficiency, it also reduces system energy consumption and improves the efficiency of system energy conservation and emission reduction.

Figure 4 is a schematic structural diagram of a controller in a heat pump dryer provided by the present invention. As shown in Figure 4, the electronic device may include: a processor (processor) 410, a communications interface (Communications Interface) 420, and a memory (memory) 430 and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 complete communication with each other through the communication bus 440. The processor 410 can call the logic instructions in the memory 430 to execute the heat pump dryer control method provided by each of the above methods. The method includes: when the heat pump dryer is heating, setting the temperature and return air outlet based on the target. temperature difference, control the operation of the compressor, and control the start and stop of the heating device to adjust the temperature increase of the return air outlet; after determining that the absolute value of the temperature difference is less than the target temperature threshold, and the humidity of the return air outlet continues to be less than the target humidity within the target duration In the event of a threshold, the heat pump dryer is controlled to stop heating.

In addition, the above-mentioned logical instructions in the memory 430 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program code. .

On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can Execute the heat pump dryer control method provided by each of the above methods. The method includes: when the heat pump dryer is heating, based on the temperature difference between the target set temperature and the return air outlet temperature, control the operation of the compressor and control the heating device Start and stop to adjust the temperature rise of the return air outlet; when it is determined that the absolute value of the temperature difference is less than the target temperature threshold, and the humidity of the return air outlet continues to be less than the target humidity threshold within the target period, the heat pump dryer is controlled to stop heating.

In another aspect, the present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. The computer program is implemented when executed by the processor to execute the heat pump dryer control method provided by each of the above methods. The method includes: when the heat pump dryer is heating, based on the temperature difference between the target set temperature and the return air outlet temperature, control the operation of the compressor, and control the start and stop of the heating device to adjust the increase in the return air outlet temperature; after determining If the absolute value of the temperature difference is less than the target temperature threshold, and the return air outlet humidity continues to be less than the target humidity threshold within the target time period, the heat pump dryer is controlled to stop heating.

The device embodiments described above are only illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in One location, or it can be distributed across multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Persons of ordinary skill in the art can understand and implement the method without any creative effort.

Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the part of the above technical solution that essentially contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., including a number of instructions to cause a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be used Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent substitutions are made to some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (7)

1. A heat pump dryer control method, comprising:

under the condition that the heat pump dryer heats, controlling the operation of a compressor based on the temperature difference between the target set temperature and the temperature of the return air inlet, and controlling the starting and stopping of a heating device so as to adjust the temperature rise of the return air inlet;

controlling the heat pump dryer to stop heating under the condition that the absolute value of the temperature difference is smaller than a target temperature threshold value and the humidity of the return air inlet in a target duration is continuously smaller than a target humidity threshold value;

the temperature difference based on the target set temperature and the return air inlet temperature controls the operation of the compressor and controls the starting and stopping of the heating device, and the method comprises the following steps:

Controlling the heating device to start and controlling the compressor to operate at the maximum operating frequency under the condition that the temperature difference between the target set temperature and the return air inlet temperature is larger than a first threshold value;

controlling the heating device to stop running and controlling the compressor to run at the maximum running frequency under the condition that the temperature difference between the target set temperature and the return air inlet temperature is larger than a second threshold value and not larger than the first threshold value;

controlling the compressor to operate based on a first operating frequency and a first control mode when the temperature difference between the target set temperature and the return air inlet temperature is greater than zero and not greater than the second threshold, wherein the first operating frequency is obtained by subtracting a first frequency threshold from the maximum operating frequency of the compressor, and the first control mode is to intermittently increase the operating frequency of the compressor;

and under the condition that the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero, controlling the compressor to operate based on the current operating frequency and a second control mode, wherein the current operating frequency is obtained by subtracting a third frequency threshold value from the operating frequency corresponding to the previous operating period, and the second control mode is to intermittently reduce the operating frequency of the compressor.

2. The heat pump dryer control method of claim 1, wherein the controlling the compressor to operate based on a first operating frequency and a first control mode includes:

under the condition that the change trend of the temperature of the return air inlet is gradually increased in the previous operation period, controlling the compressor to maintain the operation frequency corresponding to the previous operation period to operate in the current operation period; wherein, under the condition that the temperature difference between the target set temperature and the return air inlet temperature is greater than zero and not greater than the second threshold value, the corresponding operation frequency of the corresponding first operation period is the first operation frequency;

and under the condition that the change trend of the temperature of the return air inlet is not gradually increased in the previous operation period, controlling the compressor to operate based on a second operation frequency in the current operation period, wherein the second operation frequency is obtained by increasing a second frequency threshold value based on the operation frequency corresponding to the previous operation period.

3. The heat pump dryer control method of claim 1, wherein the controlling the compressor to operate based on a current operating frequency and a second control mode includes:

Under the condition that the change trend of the temperature of the return air inlet is gradually increased in the previous operation period, controlling the compressor to operate based on a third operation frequency in the current operation period, wherein the third operation frequency is obtained by subtracting a fourth frequency threshold value from the operation frequency corresponding to the previous operation period; wherein, under the condition that the temperature difference between the target set temperature and the return air inlet temperature is not more than zero, the corresponding operation frequency of the first operation period is the current operation frequency;

and under the condition that the change trend of the temperature of the return air inlet is not gradually increased in the previous operation period, controlling the compressor to maintain the operation frequency corresponding to the previous operation period to operate in the current operation period.

4. A heat pump dryer control apparatus, comprising:

the first control module is used for controlling the operation of the compressor based on the temperature difference between the target set temperature and the temperature of the return air inlet under the condition that the heat pump dryer heats, and controlling the starting and stopping of the heating device so as to adjust the temperature rise of the return air inlet;

the second control module is used for controlling the heat pump dryer to stop heating under the condition that the absolute value of the temperature difference is smaller than a target temperature threshold value and the humidity of the return air inlet in the target duration is continuously smaller than the target humidity threshold value;

The temperature difference based on the target set temperature and the return air inlet temperature controls the operation of the compressor and controls the starting and stopping of the heating device, and the method comprises the following steps:

controlling the heating device to start and controlling the compressor to operate at the maximum operating frequency under the condition that the temperature difference between the target set temperature and the return air inlet temperature is larger than a first threshold value;

controlling the heating device to stop running and controlling the compressor to run at the maximum running frequency under the condition that the temperature difference between the target set temperature and the return air inlet temperature is larger than a second threshold value and not larger than the first threshold value;

controlling the compressor to operate based on a first operating frequency and a first control mode when the temperature difference between the target set temperature and the return air inlet temperature is greater than zero and not greater than the second threshold, wherein the first operating frequency is obtained by subtracting a first frequency threshold from the maximum operating frequency of the compressor, and the first control mode is to intermittently increase the operating frequency of the compressor;

and under the condition that the temperature difference between the target set temperature and the return air inlet temperature is not greater than zero, controlling the compressor to operate based on the current operating frequency and a second control mode, wherein the current operating frequency is obtained by subtracting a third frequency threshold value from the operating frequency corresponding to the previous operating period, and the second control mode is to intermittently reduce the operating frequency of the compressor.

5. A heat pump dryer, comprising:

the dryer comprises a dryer body, an evaporator, a compressor, a condenser, a dehumidifier, a fresh air valve, an air outlet fan and a heating device;

the evaporator, the compressor, the condenser, the dehumidifier, the fresh air valve, the air outlet fan and the heating device are all arranged in the dryer body, and the heating device is arranged between the condenser and the air outlet fan;

further comprises: a controller, a temperature sensor and a humidity sensor;

the heating device, the temperature sensor and the humidity sensor are all electrically connected with the controller; the temperature sensor and the humidity sensor are both arranged at the air return opening; the temperature sensor is used for obtaining the temperature of the retrieving air opening, and the humidity sensor is used for obtaining the humidity of the retrieving air opening;

wherein the controller comprises a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the heat pump dryer control method according to any one of claims 1 to 3 when executing the program.

6. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the heat pump dryer control method according to any one of claims 1 to 3.

7. A computer program product comprising a computer program, characterized in that the computer program, when executed by a processor, implements a heat pump dryer control method as claimed in any one of claims 1 to 3.