Method for controlling electronic expansion valve in heat pump system and heat pump system

Abstract

The present application relates to a kind of control methods of electronic expansion valve in heat pump system, target exhaust temperature is accurately calculated by condensing temperature, evaporation temperature, ambient temperature and compressor operating speed, and based on the temperature difference value of target exhaust temperature and actual exhaust temperature to carry out the opening degree fine adjustment of sectioning.This method can quickly adjust the electronic expansion valve of variable frequency heat pump system in time, so that the electronic expansion valve can be adjusted in time and accurately according to environmental change and user use habit, avoid the problem of oscillation adjustment of electronic expansion valve, too long adjustment period, can reduce the energy consumption output of product and improve the use experience of user.

Description

Technical Field

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

[0002] Current inverter air conditioners, inverter heat pump systems, and other refrigeration equipment typically control the opening of the electronic expansion valve by acquiring parameters such as the compressor's direct discharge superheat, direct return superheat, or a combination of both. In this method of controlling the electronic expansion valve opening, the discharge superheat and / or return superheat parameters are directly set as electronic control parameters.

[0003] The above control methods are greatly affected by the usage environment and user habits. The set parameters cannot be adjusted in a timely manner according to environmental changes and user habits, resulting in oscillating adjustment of the electronic expansion valve. The adjustment cycle is too long, which increases the product's energy consumption and reduces the user experience. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a control method for the electronic expansion valve in a heat pump system, so as to solve the problem of oscillation adjustment of the electronic expansion valve caused by the inability of the existing control method to adjust in a timely manner according to environmental changes and user habits.

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

[0006] S10 obtains the system's condensing temperature under the current exhaust temperature control cycle T. Evaporation temperature Ambient temperature and compressor operating speed The target exhaust temperature is calculated based on the above parameters.

[0007] S20 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

[0008] S30 searches for the temperature difference value in the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is used to adjust the opening of the electronic expansion valve and maintain it for a period of time t without adjusting the valve before entering the next exhaust temperature control cycle T+1.

[0009] Compared with the prior art, the control method of the electronic expansion valve of the present invention uses condensation temperature. Evaporation temperature Ambient temperature and compressor operating speed To accurately calculate the target exhaust temperature And based on the target exhaust temperature With actual exhaust temperature temperature difference This method allows for fine-tuning of the opening degree in different zones. It enables rapid and timely adjustment of the electronic expansion valve in the variable frequency heat pump system, allowing the valve to adjust accurately and promptly based on environmental changes and user habits. This avoids issues such as oscillation and excessively long adjustment cycles, reducing energy consumption and improving the user experience.

[0010] Furthermore, the target exhaust temperature Calculate according to the following formula:

[0011]

[0012] In the formula, α represents the condensation temperature. The correction factor; β represents the evaporation temperature. The correction factor; γ represents the compressor operating speed. The correction factor; η represents the ambient temperature. The correction factor.

[0013] Furthermore, the temperature difference value Calculate according to the following formula:

[0014]

[0015] In the formula, Indicates the actual exhaust temperature. This indicates the target exhaust temperature.

[0016] Furthermore, the opening degree is adjusted according to the relationship between the temperature difference value and the gear threshold as follows:

[0017] When the temperature difference When the value is less than or equal to -10, the first fine-tuning opening ΔP1 is reduced based on the initial opening under the current exhaust temperature control cycle T.

[0018] When the temperature difference When the value is greater than -10 and less than or equal to -4, the second fine-tuning opening ΔP2 is reduced based on the initial opening under the current exhaust temperature control cycle T.

[0019] When the temperature difference When the value is greater than -4 and less than or equal to -1, the third fine-tuning opening ΔP3 is adjusted down based on the initial opening under the current exhaust temperature control cycle T.

[0020] When the temperature difference When the value is greater than -1 and less than or equal to 1, the initial opening of the valve remains unchanged under the current exhaust temperature control cycle T.

[0021] When the temperature difference When the value is greater than 1 and less than or equal to 4, the third fine-tuning opening ΔP3 is increased based on the initial opening under the current exhaust temperature control cycle T.

[0022] When the temperature difference When the value is greater than 4 and less than or equal to 10, the second fine-tuning opening ΔP2 is increased based on the initial opening under the current exhaust temperature control cycle T.

[0023] When the temperature difference When the value is greater than 10, the first fine-tuning opening ΔP1 is increased based on the initial opening under the current exhaust temperature control cycle T.

[0024] 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.

[0025] 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 controls the opening adjustment of the electronic expansion valve in the following manner:

[0026] The controller acquires the system's condensing temperature from the pressure monitoring module and temperature monitoring module during the current exhaust temperature control cycle T. Evaporation temperature Ambient temperature and compressor operating speed The target exhaust temperature is calculated based on the above parameters.

[0027] The controller acquires the actual exhaust temperature of the system from the temperature monitoring module under the current exhaust temperature control cycle T. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference

[0028] The controller searches for the temperature difference value in a preset temperature difference-opening adjustment lookup table. The corresponding opening fine-tuning value is used to adjust the opening of the electronic expansion valve and maintain it for a period of time t without adjusting the valve before entering the next exhaust temperature control cycle T+1.

[0029] Compared with the prior art, the heat pump system provided by the present invention has the same beneficial effects as the control method of the electronic expansion valve described above, which will not be elaborated here.

[0030] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention;

[0032] Figure 2 This is a flowchart of an electronic expansion valve control method according to an embodiment of the present invention. Detailed Implementation

[0033] 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.

[0034] 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 of this application and the appended claims 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” means two or more; and the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0035] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only for distinction and not to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0036] To address the problems of oscillation and excessively long adjustment cycles in existing refrigeration systems that rely on compressor discharge superheat and / or return superheat parameters to control the opening of the electronic expansion valve, which are susceptible to environmental and user habits, this invention proposes a refrigeration system that calculates the target discharge temperature based on the current compressor speed, condensing temperature, evaporating temperature, and ambient temperature. The opening of the electronic expansion valve is then controlled based on the difference between the target and actual discharge temperatures. This control method avoids oscillation 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.

[0037] For specific implementation details, please refer to [link / reference]. Figure 1 The refrigeration system proposed in this invention, taking a heat pump as an example, 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, and a pressure monitoring module 60, a temperature monitoring 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 monitoring module 60, and the temperature monitoring module 70.

[0038] 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 control the refrigerant flow rate into the air-side heat exchanger 50. Furthermore, the electromagnetic expansion valve 40 is also equipped with a filter.

[0039] The pressure monitoring 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 condensation 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, used to collect the pressure signal of the low-temperature gaseous refrigerant drawn into the compressor 10, and the refrigerant's evaporation pressure P. D The corresponding evaporation temperature T E Transmitted to the controller.

[0040] The temperature monitoring module 70 includes a first temperature sensor 71, a second temperature sensor 72, and a third temperature sensor 73. 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 DThe 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. The third temperature sensor 73 is used to collect the ambient temperature T. H and the ambient temperature T H The data is transmitted to the controller. The third temperature sensor 74 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.

[0041] The controller receives pressure and temperature signals collected by the pressure monitoring module 60 and the temperature monitoring module 70, as well as the operating speed R of the compressor 10. S The system calculates the target exhaust temperature based on the collected signals, calculates the temperature difference between the target exhaust temperature and the actual exhaust temperature, and adjusts the opening of the electronic expansion valve 40 according to the opening adjustment method of the electronic expansion valve 40 corresponding to the temperature difference value.

[0042] For details, please refer to Figure 2 The controller controls the opening degree of the electronic expansion valve in the following manner.

[0043] S10 obtains the system's condensing temperature under the current exhaust temperature control cycle T. Evaporation temperature Ambient temperature and compressor operating speed The target exhaust temperature is calculated based on the above parameters.

[0044]

[0045] In the formula, α represents the condensation temperature. The correction factor; β represents the evaporation temperature. The correction factor; γ represents the compressor operating speed. The correction factor; η represents the ambient temperature. The correction factors are determined experimentally, and can be fine-tuned at different ambient temperatures.

[0046] S20 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

[0047]

[0048] S30 searches for the temperature difference value in the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is used to adjust the opening of the electronic expansion valve and maintain it for a period of time t without adjusting the valve before entering the next exhaust temperature control cycle T+1.

[0049] The specific preset temperature difference value-opening adjustment reference table is shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] Among them, P T The initial opening is set under the current exhaust temperature control cycle T. 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.

[0054] The control method of the electronic expansion valve of the present invention uses condensation temperature. Evaporation temperature Ambient temperature and compressor operating speed To accurately calculate the target exhaust temperature And based on the target exhaust temperature With actual exhaust temperature temperature difference This method allows for fine-tuning of the opening degree in different zones. It enables rapid and timely adjustment of the electronic expansion valve in the variable frequency heat pump system, allowing the valve to adjust accurately and promptly based on environmental changes and user habits. This avoids issues such as oscillation and excessively long adjustment cycles, reducing energy consumption and improving the user experience.

[0055] 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 control method for an electronic expansion valve in a heat pump system, characterized in that, Includes the following steps: S10 Obtain the system condensation temperature under the current exhaust temperature control cycle T. Evaporation temperature Ambient temperature and compressor operating speed And calculate the target exhaust temperature based on the above parameters. ;in: In the formula, Indicates condensation temperature Correction factor; Indicates evaporation temperature Correction factor; Indicates the compressor operating speed Correction factor; Indicates ambient temperature The correction factor , , , The value was determined experimentally and fine-tuned at different ambient temperatures; S20 Obtain 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 ; S30 Searches for the temperature difference value in the preset temperature difference-opening adjustment table. The corresponding opening fine-tuning value is used to adjust the opening of the electronic expansion valve and maintain it for a period of time. Without adjusting the valve, proceed to the next exhaust temperature control cycle T+1; the temperature difference value-opening adjustment reference table is as follows: ≤-10, opening adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; in, Indicates the temperature difference value. This indicates the initial opening degree under the current exhaust temperature control cycle T. This indicates the first fine-tuning opening, which is 1 pulse. This indicates the second fine-tuning degree, which is 2 to 3 pulses. This indicates the third fine-tuning opening, which is 4 to 5 pulses.

2. The control method according to claim 1, characterized in that, The temperature difference Calculate according to the following formula: In the formula, Indicates the actual exhaust temperature. This indicates the target exhaust temperature.

3. 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 adjusts the opening of the electronic expansion valve in the following way: The controller acquires the system's condensing temperature from the pressure monitoring module and temperature monitoring module during the current exhaust temperature control cycle T. Evaporation temperature Ambient temperature and compressor operating speed And calculate the target exhaust temperature based on the above parameters. ;in: In the formula, Indicates condensation temperature Correction factor; Indicates evaporation temperature Correction factor; Indicates the compressor operating speed Correction factor; Indicates ambient temperature The correction factor , , , The value was determined experimentally and fine-tuned at different ambient temperatures; The controller acquires the actual exhaust temperature of the system from the temperature monitoring module under the current exhaust temperature control cycle T. Calculate the actual exhaust temperature With the target exhaust temperature temperature difference ; The controller searches for the temperature difference value in a preset temperature difference-opening adjustment lookup table. The corresponding opening fine-tuning value is used to adjust the opening of the electronic expansion valve and maintain it for a period of time. Without adjusting the valve, proceed to the next exhaust temperature control cycle T+1; the temperature difference value-opening adjustment reference table is as follows: ≤-10, opening adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; The opening degree is adjusted to ; in, Indicates the temperature difference value. This indicates the initial opening degree under the current exhaust temperature control cycle T. This indicates the first fine-tuning opening, which is 1 pulse. This indicates the second fine-tuning degree, which is 2 to 3 pulses. This indicates the third fine-tuning opening, which is 4 to 5 pulses.

4. The heat pump system according to claim 3, characterized in that, The temperature difference Calculate according to the following formula: In the formula, Indicates the actual exhaust temperature. This indicates the target exhaust temperature.

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