A method for controlling initial opening degree of an electronic expansion valve of a heat pump system and a heat pump system

Abstract

The present application relates to a kind of initial opening degree control method of heat pump system electronic expansion valve, and the preset initial opening degree of electronic expansion valve is accurately calculated by outdoor ambient temperature, water side heat exchanger outlet temperature and compressor target speed;And target exhaust temperature is calculated by condensing temperature, evaporation temperature and compressor operating speed, and the preset initial opening degree is fine-tuned based on the temperature difference value of the target exhaust temperature and actual exhaust temperature range, obtains the initial opening degree of system.The method can quickly adjust the initial opening degree of the electronic expansion valve of variable frequency heat pump system in time, so that the electronic expansion valve can be timely and accurately adjusted according to environmental changes and user usage habits, avoid the problem of oscillation adjustment of electronic expansion valve, too long adjustment cycle, can reduce the energy consumption output of product and improve the user experience.

Description

Technical Field

[0001] This invention relates to the field of heat pump component control, and more particularly to a method for controlling the initial opening degree of an electronic expansion valve in a heat pump system and a heat pump system thereof. Background Technology

[0002] The current method for controlling the opening of electronic expansion valves in refrigeration equipment such as variable frequency air conditioners and variable frequency heat pump systems mainly involves directly presetting a fixed initial opening and then controlling the opening of the electronic expansion valve by using exhaust superheat, return superheat, or a combination of exhaust superheat and return superheat to achieve the target opening.

[0003] The aforementioned method of controlling the opening of the electronic expansion valve by setting a fixed initial opening and then combining it with exhaust superheat and / or return superheat is based on directly setting electronic control parameters. This control method is highly susceptible to changes in the operating environment and user habits. The set electronic control parameters cannot be adaptively adjusted according to changes in machine size, operating environment, or user habits, leading to oscillating adjustment of the electronic expansion valve, excessively long adjustment cycles, increased energy consumption, and a reduced user experience. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide an initial opening control method for the electronic expansion valve of a heat pump system, so as to solve the problems of oscillation adjustment and excessively long adjustment cycle of the electronic expansion valve caused by the inability of existing control methods to adapt to environmental changes and user habits.

[0005] A method for controlling the initial opening degree of an electronic expansion valve in a heat pump system includes the following steps:

[0006] S10 obtains the outdoor ambient temperature T H Water-side heat exchanger outlet water temperature T w-out and the compressor target speed R target Calculate the preset initial opening degree K of the electronic expansion valve. p-start :

[0007] K p-start =αT H +βT w-out +γR target

[0008] In the formula, α represents the outdoor ambient temperature T. H The correction factor; β represents the outlet water temperature T of the water-side heat exchanger. w-out The correction factor; γ represents the compressor target speed R. target Correction factor;

[0009] S20 controls the opening degree of the electronic expansion valve to be the preset initial opening degree K. p-start Turn on the computer;

[0010] S30 obtains the system's condensing temperature under the current exhaust temperature control cycle T. Evaporation temperature and compressor operating speed The target exhaust temperature is calculated based on the above parameters.

[0011] S40 obtains the actual exhaust temperature of the system under the current exhaust temperature control cycle T. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference Determine the temperature difference value Is it within the allowable temperature difference range?

[0012] If so, the preset initial opening degree K p-start The initial opening K of the electronic expansion valve start ;

[0013] If not, find the temperature difference value from the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is applied to the preset initial opening K. p-start Fine-tuning is performed, and the adjusted opening is used as the initial opening K of the electronic expansion valve. start .

[0014] Furthermore, the target exhaust temperature Calculate according to the following formula:

[0015]

[0016] In the formula, δ represents the condensation temperature at the current moment. The correction factor; ε represents the evaporation temperature at the current moment. The correction factor; η represents the compressor operating speed. The correction factor, C represents other correction terms;

[0017] The temperature difference Calculate according to the following formula:

[0018]

[0019] In the formula, Indicates the actual exhaust temperature. This indicates the target exhaust temperature.

[0020] Furthermore, the allowable temperature difference range is -1 to 1.

[0021] Furthermore, the preset temperature difference value-opening adjustment reference table is shown below:

[0022] When the temperature difference When less than or equal to -10, at the preset initial opening degree K p-start Adjust the first fine-tuning opening ΔP1 downwards from the base level;

[0023] When the temperature difference When the value is greater than -10 and less than or equal to -4, the initial opening degree K is set at the preset value. p-start Adjust the second fine-tuning opening ΔP2 downwards from the base level;

[0024] When the temperature difference When the value is greater than -4 and less than or equal to -1, the initial opening degree K is set at the preset value. p-start Adjust the third fine-tuning opening ΔP3 downwards from the base level;

[0025] When the temperature difference When the value is greater than 1 and less than or equal to 4, the initial opening K is set at a preset value. p-start The third fine-tuning opening ΔP3 is increased based on the existing setting.

[0026] When the temperature difference When the value is greater than 4 and less than or equal to 10, the initial opening K is set at the preset value. p-start The second fine-tuning opening ΔP2 is increased based on the existing adjustment.

[0027] When the temperature difference When it is greater than 10, the preset initial opening degree K is used. p-start The first fine-tuning opening ΔP1 is increased based on the existing setting.

[0028] Furthermore, the first fine-tuning opening ΔP3 is 1 pulse; the second fine-tuning opening ΔP2 is 2 to 3 pulses; and the third fine-tuning opening ΔP3 is 4 to 5 pulses.

[0029] Compared with the prior art, the initial opening control method of the electronic expansion valve of the heat pump system of the present invention is based on the outdoor ambient temperature T. H Water-side heat exchanger outlet water temperature T w-out and the compressor target speed R target To accurately calculate the preset initial opening K of the electronic expansion valve p-start ; and through condensation temperature Evaporation temperature and compressor operating speed To calculate the target exhaust temperature And based on the target exhaust temperature Temperature difference between the actual exhaust temperature and the actual exhaust temperature The range is used to define the preset initial opening degree K. p-startFine-tuning is performed to obtain the initial opening of the system. This method can quickly and timely adjust the initial opening of the electronic expansion valve of the variable frequency heat pump system, enabling the electronic expansion valve to make timely and accurate adjustments according to environmental changes and user habits. This avoids problems such as oscillation adjustment and excessively long adjustment cycles of the electronic expansion valve, thereby reducing the energy consumption output of the product and improving the user experience.

[0030] Meanwhile, this invention provides a heat pump system, including a compressor, a four-way valve, a water-side heat exchanger, an electronic expansion valve, and an air-side heat exchanger connected sequentially via a refrigerant circulation pipeline, as well as a pressure monitoring module, a temperature monitoring module, and a controller electrically and / or communicatively connected to the compressor, electronic expansion valve, pressure monitoring module, and temperature monitoring module. The controller obtains the initial opening degree of the electronic expansion valve in the following manner:

[0031] S10 obtains the outdoor ambient temperature T H Water-side heat exchanger outlet water temperature T w-out and the compressor target speed R target Calculate the preset initial opening degree K of the electronic expansion valve. p-start :

[0032] K p-start =αT H +βT w-out +γR target

[0033] In the formula, α represents the outdoor ambient temperature T. H The correction factor; β represents the outlet water temperature T of the water-side heat exchanger. w-out The correction factor; γ represents the compressor target speed R. target Correction factor;

[0034] S20 controls the opening degree of the electronic expansion valve to be the preset initial opening degree K. p-start Turn on the computer;

[0035] S30 obtains the system's condensing temperature under the current exhaust temperature control cycle T. Evaporation temperature and compressor operating speed The target exhaust temperature is calculated based on the above parameters.

[0036] S40 obtains the actual exhaust temperature of the system under the current exhaust temperature control cycle T. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference Determine the temperature difference value Is it within the allowable temperature difference range?

[0037] If so, the preset initial opening degree K p-start The initial opening K of the electronic expansion valve start ;

[0038] If not, find the temperature difference value from the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is applied to the preset initial opening K. p-start Fine-tuning is performed, and the adjusted opening is used as the initial opening K of the electronic expansion valve. start .

[0039] Compared with the prior art, the heat pump system provided by the present invention has the same beneficial effects as the above-mentioned electronic expansion valve initial opening control method, which will not be elaborated here.

[0040] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention;

[0042] Figure 2 This is a flowchart of an electronic expansion valve control method according to an embodiment of the present invention. Detailed Implementation

[0043] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention.

[0044] To address the problems in existing refrigeration systems where the electronic expansion valve is controlled by directly presetting a fixed initial opening and then using either exhaust superheat, return superheat, or a combination of both to achieve the target opening, the method is susceptible to environmental and user-specific variations, leading to oscillations and excessively long adjustment cycles. This invention proposes a new initial opening control method for the electronic expansion valve in a heat pump system. This method precisely calculates the target initial opening and target exhaust temperature to control the valve's opening. This approach avoids oscillations and excessively long adjustment cycles, allowing the electronic expansion valve to adapt to environmental changes and user habits in real-time. This enables rapid and timely adjustment of the variable frequency heat pump system, reducing energy consumption and improving the user experience.

[0045] For specific implementation details, please refer to [link / reference]. Figure 1The heat pump system proposed in this invention includes a compressor 10, a four-way valve 20, a water-side heat exchanger 30, an electronic expansion valve 40, an air-side heat exchanger 50, a pressure detection module 60, a temperature detection module 70, a fan 80 located next to the air-side heat exchanger 50, a controller (not shown), and other auxiliary pipes. The controller is electrically or communicatively connected to the compressor 10, the electronic expansion valve 40, the pressure detection module 60, and the temperature detection module 70.

[0046] An electromagnetic expansion valve 40 is installed on the refrigerant pipeline between the water-side heat exchanger 30 and the air-side heat exchanger 50 to throttle the medium-temperature, high-pressure liquid refrigerant into a low-temperature, low-pressure refrigerant. Furthermore, the electromagnetic expansion valve 40 is also equipped with a filter.

[0047] The pressure detection module 60 includes a first pressure sensor 61 and a second pressure sensor 62. The first pressure sensor 61 is located between the discharge end of the compressor 10 and the liquid inlet of the four-way valve, and is used to collect the pressure signal of the high-temperature and high-pressure liquid refrigerant discharged by the compressor 10, and to convert the high pressure P of the refrigerant into a signal. H The corresponding condensation temperature T C The signal is transmitted to the controller. The second pressure sensor 72 is located between the inlet of the compressor 10 and the outlet of the four-way valve. It is used to collect the pressure signal of the low-temperature, low-pressure gaseous refrigerant drawn into the compressor 10 and to transmit the refrigerant low-pressure P signal to the controller. D The corresponding evaporation temperature T E Transmitted to the controller.

[0048] The temperature detection module 70 includes a first temperature sensor 71, a second temperature sensor 72, a third temperature sensor 73, a fourth temperature sensor 74, and a fifth temperature sensor 75. The first temperature sensor 71 is located at the discharge end of the compressor 10 and is used to collect the actual discharge temperature T of the compressor 10. D and the actual exhaust temperature T D The data is transmitted to the controller. The second temperature sensor 72 is located at the return gas end of the compressor 10 and is used to collect the actual return gas temperature T of the compressor 10. B and the actual return gas temperature T B The data is transmitted to the controller. A third temperature sensor 73 is located at the inlet of the water-side heat exchanger 30 to collect the inlet water temperature T. in-w and the inlet water temperature T w-in The data is transmitted to the controller. The fourth temperature sensor 74 is located at the outlet of the water-side heat exchanger 30 and is used to collect the outlet water temperature T. w-out and set the outlet water temperature T out-w The data is transmitted to the controller. The fifth temperature sensor, 75, is used to collect the ambient temperature T. H and the ambient temperature T HThe data is transmitted to the controller. The fifth temperature sensor 75 can be located on the outside of the air-side heat exchanger 30 or on the heat pump system casing. This application does not impose any restrictions.

[0049] The controller receives pressure and temperature signals collected by the pressure detection module 60 and temperature detection module 70, as well as the operating speed R of the compressor 10. S Based on the collected signals, the initial opening degree of the electronic expansion valve and the target exhaust temperature are calculated. The temperature difference between the target exhaust temperature and the actual exhaust temperature is calculated, and the opening degree of the electronic expansion valve 40 is adjusted according to the opening degree adjustment method of the electronic expansion valve 40 corresponding to the temperature difference value.

[0050] For details, please refer to Figure 2 The controller controls the opening degree of the electronic expansion valve in the following manner.

[0051] S10 obtains the outdoor ambient temperature T H Water-side heat exchanger outlet water temperature T w-out and the compressor target speed R target And calculate the preset initial opening degree K of the electronic expansion valve based on the above parameters. p-start :

[0052] K p-start =αT H +βT w-out +γR target

[0053] In the formula, α represents the outdoor ambient temperature T. H The correction factor; β represents the outlet water temperature T of the water-side heat exchanger. w-out The correction factor; γ represents the compressor target speed R. target The correction factors are determined based on factory tests and can be fine-tuned under different ambient temperatures.

[0054] S20 controls the opening degree of the electronic expansion valve to be the preset initial opening degree K. p-start Turn on the computer.

[0055] S30 obtains the current condensation temperature of the system. Evaporation temperature and compressor operating speed The target exhaust temperature at the current moment is calculated based on the above parameters.

[0056]

[0057] In the formula, δ represents the condensation temperature at the current moment. The correction factor; ε represents the evaporation temperature at the current moment. The correction factor; η represents the compressor operating speed. The correction factor is denoted by C, which represents other correction terms. The values ​​of δ, ε, η, and C are determined based on factory testing and can be fine-tuned under different ambient temperatures.

[0058] S40 obtains the system's actual exhaust temperature at the current moment. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference

[0059]

[0060] S50 determines the temperature difference value Is it within the tolerance range?

[0061] If so, then the preset initial opening degree K is used. p-start The initial opening K of the electronic expansion valve start Entering PID control mode;

[0062] If not, then look up the temperature difference value from the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value corresponds to the preset initial opening K of the electronic expansion valve. p-start Adjustments are made to obtain the initial opening degree K of the electronic expansion valve. start Then, it enters the working PID control mode.

[0063] The tolerance range is -1 to 1.

[0064] The specific preset temperature difference value-opening adjustment reference table is shown in Table 1.

[0065] Table 1

[0066]

[0067] Among them, K p-start To preset the initial opening, the first fine-tuning opening ΔP3 is 1 pulse; the second fine-tuning opening ΔP2 is 2 to 3 pulses; and the third fine-tuning opening ΔP3 is 4 to 5 pulses.

[0068] The initial opening control method of the electronic expansion valve of the heat pump system of the present invention is based on the outdoor ambient temperature T. H Water-side heat exchanger outlet water temperature T w-out and the compressor target speed R target To accurately calculate the preset initial opening K of the electronic expansion valve p-start ; and through condensation temperature Evaporation temperature and compressor operating speed To calculate the target exhaust temperature And based on the target exhaust temperature Temperature difference between the actual exhaust temperature and the actual exhaust temperature The range is used to define the preset initial opening degree K. p-start Fine-tuning is performed to obtain the initial opening degree of the system, and the system then enters the operating PID opening adjustment mode based on this initial opening degree. This method can quickly and timely adjust the initial opening degree of the electronic expansion valve of the variable frequency heat pump system, enabling the electronic expansion valve to make timely and accurate adjustments according to environmental changes and user habits. This avoids problems such as oscillation adjustment and excessively long adjustment cycles of the electronic expansion valve, thereby reducing the product's energy consumption output and improving the user experience.

[0069] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments and claims of this application are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” and “several” refer to two or more; “and / or” refers to and includes any or all possible combinations of one or more associated listed items; “first,” “second,” “third,” etc., are used only to distinguish and not to describe a particular order or sequence, nor should they be construed as indicating or implying relative importance. When the above description relates to drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of this application, those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0070] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A method for controlling the initial opening degree of an electronic expansion valve in a heat pump system, characterized in that, Includes the following steps: S10 obtains outdoor ambient temperature Water-side heat exchanger outlet water temperature and compressor target speed Calculate the preset initial opening degree of the electronic expansion valve. : In the formula, Indicates outdoor ambient temperature Correction factor; Indicates the outlet water temperature of the water-side heat exchanger Correction factor; Indicates the target speed of the compressor Correction factor; S20 controls the opening degree of the electronic expansion valve to the preset initial opening degree. Turn on the computer; S30 Obtains the system condensation temperature under the current exhaust temperature control cycle T. Evaporation temperature and compressor operating speed And calculate the target exhaust temperature based on the above parameters. ; S40 Obtains the actual exhaust temperature of the system under the current exhaust temperature control cycle T. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference Determine the temperature difference value Is it within the allowable temperature difference range? If so, the preset initial opening degree is used. As the initial opening of the electronic expansion valve ; If not, find the temperature difference value from the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is relative to the preset initial opening. Fine-tuning is performed, and the adjusted opening is used as the initial opening of the electronic expansion valve. ; The preset temperature difference value-opening adjustment table is shown below: When the temperature difference When less than or equal to -10, at the preset initial opening degree Adjust the first fine-tuning degree based on the existing settings. ; When the temperature difference When the value is greater than -10 and less than or equal to -4, the preset initial opening degree is... Adjust the second fine-tuning degree based on the existing settings. ; When the temperature difference When the value is greater than -4 and less than or equal to -1, the preset initial opening degree is... Adjust the third fine-tuning degree based on the existing settings. ; When the temperature difference When the value is greater than 1 and less than or equal to 4, the initial opening is set at the preset value. Increase the third fine-tuning opening based on the existing settings. ; When the temperature difference When the value is greater than 4 and less than or equal to 10, the initial opening is set at the preset value. Increase the second fine-tuning opening based on the existing settings. ; When the temperature difference When the value is greater than 10, the initial opening is set at the preset value. Increase the first fine-tuning opening based on the existing settings. ; Among them, the first fine-tuning opening The first pulse is the first pulse; the second fine-tuning opening is... For 2 to 3 pulses; third fine-tuning opening. It consists of 4 to 5 pulses.

2. The initial opening degree control method according to claim 1, characterized in that, The target exhaust temperature Calculate according to the following formula: ； In the formula, Indicates the condensation temperature at the current moment. Correction factor; Indicates the evaporation temperature at the current moment. Correction factor; Indicates the compressor operating speed The correction factor Indicates other correction terms; The temperature difference Calculate according to the following formula: In the formula, Indicates the actual exhaust temperature. This indicates the target exhaust temperature.

3. The control method according to claim 1 or 2, characterized in that, The allowable temperature difference range is -1 to 1.

4. A heat pump system, comprising a compressor, a four-way valve, a water-side heat exchanger, an electronic expansion valve, and an air-side heat exchanger connected sequentially via a refrigerant circulation pipeline, a pressure monitoring module, a temperature monitoring module, and a controller electrically and / or communicatively connected to the compressor, the electronic expansion valve, the pressure monitoring module, and the temperature monitoring module, characterized in that, The controller obtains the initial opening of the electronic expansion valve in the following manner: S10 obtains outdoor ambient temperature Water-side heat exchanger outlet water temperature and compressor target speed Calculate the preset initial opening degree of the electronic expansion valve. : In the formula, Indicates outdoor ambient temperature Correction factor; Indicates the outlet water temperature of the water-side heat exchanger Correction factor; Indicates the target speed of the compressor Correction factor; S20 controls the opening degree of the electronic expansion valve to the preset initial opening degree. Turn on the computer; S30 Obtains the system condensation temperature under the current exhaust temperature control cycle T. Evaporation temperature and compressor operating speed And calculate the target exhaust temperature based on the above parameters. ; S40 Obtains the actual exhaust temperature of the system under the current exhaust temperature control cycle T. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference Determine the temperature difference value Is it within the allowable temperature difference range? If so, the preset initial opening degree is used. As the initial opening of the electronic expansion valve ; If not, find the temperature difference value from the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is relative to the preset initial opening. Fine-tuning is performed, and the adjusted opening is used as the initial opening of the electronic expansion valve. ; The preset temperature difference value-opening adjustment table is shown below: When the temperature difference When less than or equal to -10, at the preset initial opening degree Adjust the first fine-tuning degree based on the existing settings. ; When the temperature difference When the value is greater than -10 and less than or equal to -4, the preset initial opening degree is... Adjust the second fine-tuning degree based on the existing settings. ; When the temperature difference When the value is greater than -4 and less than or equal to -1, the preset initial opening degree is... Adjust the third fine-tuning degree based on the existing settings. ; When the temperature difference When the value is greater than 1 and less than or equal to 4, the initial opening is set at the preset value. Increase the third fine-tuning opening based on the existing settings. ; When the temperature difference When the value is greater than 4 and less than or equal to 10, the initial opening is set at the preset value. Increase the second fine-tuning opening based on the existing settings. ; When the temperature difference When the value is greater than 10, the initial opening is set at the preset value. Increase the first fine-tuning opening based on the existing settings. ; Among them, the first fine-tuning opening The first pulse is the first pulse; the second fine-tuning opening is... For 2 to 3 pulses; third fine-tuning opening. It consists of 4 to 5 pulses.

5. The heat pump system according to claim 4, characterized in that, The target exhaust temperature Calculate according to the following formula: ； In the formula, Indicates the condensation temperature at the current moment. Correction factor; Indicates the evaporation temperature at the current moment. Correction factor; Indicates the compressor operating speed The correction factor Indicates other correction terms; The temperature difference Calculate according to the following formula: In the formula, Indicates the actual exhaust temperature. This indicates the target exhaust temperature.

6. The heat pump system according to claim 4 or 5, characterized in that, The allowable temperature difference range is -1 to 1.

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