Air conditioner and control method, device, storage medium and computer program product thereof

Abstract

The application discloses an air conditioner and a control method, device, storage medium and computer program product thereof. The method comprises the following steps: after starting in a current mode, obtaining a condensing side load in the current mode; determining an initial PWM duty cycle in the current mode according to the condensing side load in the current mode; controlling the opening degree of a throttling device according to the initial PWM duty cycle in the current mode; obtaining an evaporator outlet superheat in the current mode after a first set time; correcting the initial PWM duty cycle in the current mode according to the evaporator outlet superheat in the current mode to obtain a corrected PWM duty cycle in the current mode; and adjusting the opening degree of the throttling device according to the corrected PWM duty cycle in the current mode. According to the scheme, the opening degree of the expansion valve is controlled in the PWM mode, the PWM duty cycle is determined in combination with the condensing side load and the evaporator outlet superheat, the expansion valve flow is accurately controlled, the noise is reduced, and the user experience is improved.

Description

Technical Field

[0001] This invention belongs to the field of air conditioner technology, specifically relating to an air conditioner control method, device, air conditioner, storage medium, and computer program product, and particularly to an air conditioner noise reduction control method, device, air conditioner, storage medium, and computer program product. Background Technology

[0002] In air conditioners, expansion valves (such as electronic expansion valves located on the outdoor side and used for throttling) generate noise when regulating refrigerant flow, which affects the user experience due to the throttling effect.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a control method, device, air conditioner, storage medium, and computer program product for an air conditioner, in order to solve the problem that the expansion valve in the air conditioner generates noise when regulating the refrigerant flow, which affects the user experience. The invention achieves the effect of controlling the opening of the expansion valve by adopting PWM mode and determining the PWM duty cycle by combining the condenser side load and the evaporator outlet superheat of the air conditioner, so as to accurately control the expansion valve flow, reduce noise, and improve the user experience.

[0005] This invention provides a control method for an air conditioner, the air conditioner having a throttling device, the opening degree of which can be controlled according to a preset PWM mode; the control method for the air conditioner includes: when the air conditioner is turned on and running in the current mode, acquiring the condenser-side load of the air conditioner in the current mode; determining an initial PWM duty cycle in the current mode based on the condenser-side load of the air conditioner in the current mode; controlling the opening degree of the throttling device according to the initial PWM duty cycle in the current mode; after a first set time, acquiring the evaporator outlet superheat in the air conditioner in the current mode; correcting the initial PWM duty cycle in the current mode based on the evaporator outlet superheat in the current mode to obtain a corrected PWM duty cycle in the current mode; and adjusting the opening degree of the throttling device according to the corrected PWM duty cycle in the current mode.

[0006] In some implementations, the current mode includes: a cooling mode and a heating mode; obtaining the condenser-side load of the air conditioner in the current mode includes: when the current mode is cooling mode, obtaining the outdoor ambient temperature of the air conditioner as the condenser-side load of the air conditioner in cooling mode; when the current mode is heating mode, obtaining the indoor ambient temperature of the air conditioner as the condenser-side load of the air conditioner in heating mode.

[0007] In some implementations, when the current mode is cooling mode, the condenser-side load of the air conditioner in the current mode is the outdoor ambient temperature of the air conditioner; determining the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode includes: in cooling mode, determining whether the outdoor ambient temperature of the air conditioner is greater than or equal to a first set outer ring temperature, and determining whether the outdoor ambient temperature of the air conditioner is less than a second set outer ring temperature; wherein, the first set outer ring temperature is greater than the second set outer ring temperature; if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the first set outer ring temperature, then it is determined that the operating environment of the throttling device belongs to the first... A cooling pressure zone is set, and the initial PWM duty cycle in the current mode is determined to be the first set cooling duty cycle. If the outdoor ambient temperature of the air conditioner is determined to be greater than or equal to the second set outer ring temperature and less than the first set outer ring temperature, then the initial PWM duty cycle in the current mode is determined to be the default duty cycle. If the outdoor ambient temperature of the air conditioner is determined to be less than the second set outer ring temperature, then the operating environment of the throttling device is determined to be in the second set cooling pressure zone, and the initial PWM duty cycle in the current mode is determined to be the second set cooling duty cycle. Wherein, the pressure in the second set cooling pressure zone is less than the pressure in the first set cooling pressure zone, and the second set cooling duty cycle is less than the first set cooling duty cycle.

[0008] In some implementations, when the current mode is cooling mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in cooling mode. Based on the evaporator outlet superheat in the current mode, the initial PWM duty cycle in the current mode is corrected to obtain the corrected PWM duty cycle in the current mode. This includes: in cooling mode, determining whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; if the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; if the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, then the initial PWM duty cycle in the current mode is maintained; if the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the set duty cycle decrease method in the current mode to obtain the corrected PWM duty cycle in the current mode.

[0009] In some implementations, when the current mode is heating mode, the condenser-side load of the air conditioner in the current mode is the indoor ambient temperature of the air conditioner; determining the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode further includes: in heating mode, determining whether the indoor ambient temperature of the air conditioner is greater than or equal to a first set inner ring temperature, and determining whether the indoor ambient temperature of the air conditioner is less than a second set inner ring temperature; wherein, the first set inner ring temperature is greater than the second set inner ring temperature; if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the first set inner ring temperature, then it is determined that the operating environment of the throttling device belongs to the first... A first set heating pressure zone is defined, and the initial PWM duty cycle of the current mode is determined as the first set heating duty cycle. If the indoor ambient temperature of the air conditioner is determined to be greater than or equal to the second set inner ring temperature and less than the first set inner ring temperature, then the initial PWM duty cycle of the current mode is determined to be the default duty cycle. If the indoor ambient temperature of the air conditioner is determined to be less than the second set inner ring temperature, then the operating environment of the throttling device is determined to be within the second set heating pressure zone, and the initial PWM duty cycle of the current mode is determined to be the second set heating duty cycle. Wherein, the pressure of the second set heating pressure zone is less than the pressure of the first set heating pressure zone, and the second set heating duty cycle is less than the first set heating duty cycle.

[0010] In some implementations, when the current mode is heating mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the heating mode. The process of correcting the initial PWM duty cycle in the current mode based on the evaporator outlet superheat in the current mode to obtain a corrected PWM duty cycle in the current mode further includes: in heating mode, determining whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; if it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, then increasing the initial PWM duty cycle in the current mode according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; if it is determined that the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, then maintaining the initial PWM duty cycle in the current mode; if it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, then increasing the initial PWM duty cycle in the current mode according to the set duty cycle decrease method in the current mode to obtain the corrected PWM duty cycle in the current mode.

[0011] In conjunction with the above method, another aspect of the present invention provides a control device for an air conditioner, the air conditioner having a throttling device, the opening degree of which can be controlled according to a preset PWM mode; the control device for the air conditioner includes: an acquisition unit configured to acquire the condenser-side load of the air conditioner in the current mode when the air conditioner is turned on and running in the current mode; a control unit configured to determine an initial PWM duty cycle in the current mode based on the condenser-side load of the air conditioner in the current mode; the control unit is further configured to control the opening degree of the throttling device according to the initial PWM duty cycle in the current mode; the acquisition unit is further configured to acquire the evaporator outlet superheat in the air conditioner in the current mode after a first set time; the control unit is further configured to correct the initial PWM duty cycle in the current mode based on the evaporator outlet superheat in the current mode to obtain a corrected PWM duty cycle in the current mode; the control unit is further configured to adjust the opening degree of the throttling device according to the corrected PWM duty cycle in the current mode.

[0012] In some implementations, the current mode includes a cooling mode and a heating mode; the acquisition unit acquires the condenser-side load of the air conditioner in the current mode, including: when the current mode is cooling mode, acquiring the outdoor ambient temperature of the air conditioner as the condenser-side load of the air conditioner in cooling mode; when the current mode is heating mode, acquiring the indoor ambient temperature of the air conditioner as the condenser-side load of the air conditioner in heating mode.

[0013] In some implementations, when the current mode is cooling mode, the condenser-side load of the air conditioner in the current mode is the outdoor ambient temperature of the air conditioner; the control unit determines the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode, including: in cooling mode, determining whether the outdoor ambient temperature of the air conditioner is greater than or equal to a first set outer ring temperature, and determining whether the outdoor ambient temperature of the air conditioner is less than a second set outer ring temperature; wherein, the first set outer ring temperature is greater than the second set outer ring temperature; if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the first set outer ring temperature, then the operating environment of the throttling device is determined. If the air conditioner's outdoor ambient temperature is greater than or equal to the second set outer ring temperature and less than the first set outer ring temperature, then the initial PWM duty cycle in the current mode is determined to be the default duty cycle. If the air conditioner's outdoor ambient temperature is less than the second set outer ring temperature, then the operating environment of the throttling device is determined to be within the second set cooling pressure zone, and the initial PWM duty cycle in the current mode is determined to be the second set cooling duty cycle. Wherein, the pressure in the second set cooling pressure zone is less than the pressure in the first set cooling pressure zone, and the second set cooling duty cycle is less than the first set cooling duty cycle.

[0014] In some implementations, when the current mode is cooling mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in cooling mode. The control unit corrects the initial PWM duty cycle in the current mode based on the evaporator outlet superheat in the current mode to obtain the corrected PWM duty cycle in the current mode, including: in cooling mode, determining whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; if it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; if it is determined that the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, then the initial PWM duty cycle in the current mode is maintained; if it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the set duty cycle decrease method in the current mode to obtain the corrected PWM duty cycle in the current mode.

[0015] In some implementations, when the current mode is heating mode, the condenser-side load of the air conditioner in the current mode is the indoor ambient temperature of the air conditioner; the control unit, based on the condenser-side load of the air conditioner in the current mode, determines the initial PWM duty cycle of the current mode, and further includes: in heating mode, determining whether the indoor ambient temperature of the air conditioner is greater than or equal to a first set inner ring temperature, and determining whether the indoor ambient temperature of the air conditioner is less than a second set inner ring temperature; wherein, the first set inner ring temperature is greater than the second set inner ring temperature; if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the first set inner ring temperature, then the operating environment of the throttling device is determined. If the air conditioner's indoor ambient temperature is greater than or equal to the second set inner ring temperature and less than the first set inner ring temperature, then the initial PWM duty cycle in the current mode is determined to be the default duty cycle. If the air conditioner's indoor ambient temperature is less than the second set inner ring temperature, then the operating environment of the throttling device is determined to be within the second set heating pressure zone, and the initial PWM duty cycle in the current mode is determined to be the second set heating duty cycle. Wherein, the pressure in the second set heating pressure zone is less than the pressure in the first set heating pressure zone, and the second set heating duty cycle is less than the first set heating duty cycle.

[0016] In some implementations, when the current mode is heating mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the heating mode. The control unit, based on the evaporator outlet superheat in the current mode, corrects the initial PWM duty cycle in the current mode to obtain the corrected PWM duty cycle in the current mode. The method further includes: in heating mode, determining whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; if the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, increasing the initial PWM duty cycle in the current mode according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; if the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, maintaining the initial PWM duty cycle in the current mode; if the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, increasing the initial PWM duty cycle in the current mode according to the set duty cycle decrease method in the current mode to obtain the corrected PWM duty cycle in the current mode.

[0017] In conjunction with the above-described device, the present invention further provides an air conditioner, comprising: the control device for the air conditioner described above.

[0018] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the steps of the control method for the air conditioner described above.

[0019] In conjunction with the above method, the present invention further provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the control method for the air conditioner described above.

[0020] Therefore, the solution of the present invention, targeting the throttling device (such as an expansion valve) in an air conditioner, detects the condensing-side load of the air conditioner (such as the outdoor ambient temperature in cooling mode or the indoor ambient temperature in heating mode) when the air conditioner is turned on and running in the current mode (such as cooling mode or heating mode); based on the level of the condensing-side load of the air conditioner, it determines whether the operating environment of the expansion valve belongs to a first pressure zone (such as a high-pressure zone) or a second pressure zone (such as a low-pressure zone); if the operating environment of the expansion valve belongs to the high-pressure zone, the first duty cycle of the current mode (such as the high duty cycle of the current mode) is used as the initial duty cycle to control the opening degree of the expansion valve; .... If the environment is in a low-pressure zone, the second duty cycle of the current mode (such as the lower duty cycle of the current mode) is used as the initial duty cycle to control the opening of the expansion valve. After the first set time (such as 15 minutes), the superheat of the evaporator outlet in the current mode is detected. The initial duty cycle of the current mode is corrected according to the superheat of the evaporator outlet in the current mode to obtain the corrected duty cycle, and the opening of the expansion valve is controlled according to the corrected duty cycle of the current mode. Thus, by using PWM mode to control the opening of the expansion valve, and combining the condenser side load of the air conditioner and the superheat of the evaporator outlet to determine the PWM duty cycle, the flow rate of the expansion valve can be precisely controlled, noise can be reduced, and the user experience can be improved.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating an embodiment of the control method for an air conditioner according to the present invention;

[0024] Figure 2 This is a flowchart illustrating an embodiment of the method of the present invention for determining the initial PWM duty cycle in the current mode under cooling mode;

[0025] Figure 3This is a schematic flowchart of an embodiment of the method of the present invention for correcting the initial PWM duty cycle in the current mode under the cooling mode;

[0026] Figure 4 This is a flowchart illustrating an embodiment of the method of the present invention for determining the initial PWM duty cycle in the current mode under heating mode;

[0027] Figure 5 This is a schematic flowchart of an embodiment of the method of the present invention for correcting the initial PWM duty cycle in the current mode under heating mode;

[0028] Figure 6 This is a schematic diagram of the structure of an embodiment of the control device for an air conditioner according to the present invention;

[0029] Figure 7 This is a schematic diagram of the overall control flow of a noise reduction control method for an air conditioner;

[0030] Figure 8 This is a schematic diagram of the control flow of a noise reduction control method for an air conditioner in cooling mode.

[0031] Figure 9 This is a schematic diagram of the control flow of a noise reduction control method for an air conditioner in heating mode.

[0032] Figure 10 Table 1 shows the relationship between temperature and pressure in the cooling mode of an air conditioner.

[0033] Figure 11 Table 2 shows the relationship between temperature and pressure in the cooling mode of an air conditioner.

[0034] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0035] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] Considering that the expansion valve in an air conditioner generates noise when regulating refrigerant flow, affecting the user experience, especially in inverter air conditioners where compressor frequency changes affect noise levels (typically low-frequency, continuous sounds that may vary with air conditioner load), and unstable system pressure leading to poor refrigerant flow, abnormal noises such as whistling can easily occur. Therefore, air conditioner noise issues are not only related to the expansion valve's structural design but also closely related to system design factors such as refrigerant flow and system pressure control methods.

[0038] In related solutions, the expansion valve opening control scheme in air conditioners relies on PID (Proportional-Integral-Derivative) continuous adjustment, which cannot avoid fluid vibration at a specific opening degree. This vibration is easily accompanied by whistling sounds and refrigerant flow noise. Because the valve needle and valve body are in continuous contact during the expansion valve opening adjustment process, the collision between the refrigerant pulsation and the valve body and valve needle itself generates flow noise. At a specific opening degree, such as when the opening is too small during throttling, due to the narrow flow channel and the sharp increase in refrigerant velocity, strong turbulence is generated at the narrow valve orifice, resulting in a sudden drop in local pressure. This leads to flash evaporation and instantaneous vaporization of the refrigerant. The bursting of bubbles in the flow channel generates a huge instantaneous impact force, forming a high-frequency crackling sound in the system, which is the whistling sound.

[0039] Therefore, the present invention proposes a control method for an air conditioner, specifically a noise reduction control method for an air conditioner, based on a pulse width modulation (PWM) intelligent expansion valve system. By adjusting the duty cycle, precise control of the expansion valve flow can be achieved; through a dynamic flow compensation algorithm, pressure oscillation is suppressed, noise is reduced, and user experience is improved.

[0040] According to embodiments of the present invention, a control method for an air conditioner is provided, such as... Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. The air conditioner has a throttling device, the opening degree of which can be controlled according to a preset PWM mode, that is, the opening degree of the throttling device can be controlled by adjusting the PWM duty cycle; of course, the air conditioner also has an outdoor heat exchanger, an indoor heat exchanger, and a compressor, etc., and the throttling device is such as an expansion valve; in the current mode of the air conditioner, one of the outdoor heat exchanger and the indoor heat exchanger is a condenser, and the other is an evaporator. The preset PWM mode is a mode that adjusts the opening degree of the throttling device by adjusting the PWM duty cycle of the drive signal of the throttling device opening degree control component. In the solution of the present invention, as... Figure 1 As shown, the control method for the air conditioner includes:

[0041] When the air conditioner is turned on and running in the current mode, the condenser-side load of the air conditioner in the current mode is obtained.

[0042] Based on the condenser-side load of the air conditioner in the current mode, the initial PWM duty cycle for the current mode is determined. The initial PWM duty cycle for the current mode is the PWM duty cycle of the drive signal used to adjust the opening control component of the throttling device in the current mode.

[0043] The opening degree of the throttling device is controlled according to the initial PWM duty cycle in the current mode.

[0044] After the air conditioner controls the opening degree of the throttling device for a first set time according to the initial PWM duty cycle of the current mode, the evaporator outlet superheat of the air conditioner in the current mode is obtained.

[0045] Based on the evaporator outlet superheat in the current mode, the initial PWM duty cycle in the current mode is corrected to obtain the corrected PWM duty cycle in the current mode. The corrected PWM duty cycle in the current mode is the PWM duty cycle of the drive signal used to adjust the opening control component of the throttling device in the current mode.

[0046] Adjust the opening of the throttling device according to the modified PWM duty cycle in the current mode to precisely control the expansion valve flow and reduce noise.

[0047] The present invention proposes an air conditioner noise reduction control scheme based on a pulse width modulation (PWM) intelligent expansion valve system. By adjusting the duty cycle, the flow rate of the expansion valve can be precisely controlled. Through a dynamic flow compensation algorithm, pressure oscillation is suppressed, resonance points are skipped to avoid vibration and howling, thus reducing noise and improving user experience.

[0048] In some implementations, the current mode includes: a cooling mode and a heating mode.

[0049] Step S110 involves obtaining the condenser-side load of the air conditioner in the current mode, including:

[0050] When the current mode is cooling mode, the outdoor ambient temperature of the air conditioner is obtained as the condenser-side load of the air conditioner in cooling mode; the outdoor ambient temperature of the air conditioner is like the outdoor ambient temperature T outer ring.

[0051] When the current mode is heating mode, the indoor ambient temperature of the air conditioner is obtained as the condensing load of the air conditioner in heating mode; the indoor ambient temperature of the air conditioner is the same as the outdoor ambient temperature T_inner ring.

[0052] Figure 7 This is a schematic diagram of the overall control flow of a noise reduction control method for an air conditioner. Figure 7 As shown, the overall control flow of the air conditioner noise reduction control method includes:

[0053] Step 11: Detect and report the room load status, then proceed to step 12.

[0054] Step 12: Determine whether the expansion valve operates in a high-pressure or low-pressure zone, then proceed to Step 13. The system's operating range is divided into high-pressure and low-pressure zones based on the condenser-side load; during cooling, the outdoor ambient temperature is used as the basis, and during heating, the indoor ambient temperature is used. The high-pressure and low-pressure zones are defined by the load: a high condenser-side load defines the high-pressure zone, and a low condenser-side load defines the low-pressure zone.

[0055] Step 13: Obtain the evaporator outlet superheat, and then proceed to step 14.

[0056] Step 14: Correct the PWM duty cycle in real time according to the dynamic flow compensation algorithm. The duty cycle represents the proportion of the valve core fully open period to the total period, ranging from 0% to 100%, and is represented by the letter N.

[0057] In the noise reduction control scheme for an air conditioner proposed in this invention, a pulse width modulation (PWM) module is embedded in the air conditioner control board. Based on the PWM-based intelligent expansion valve system, the output signal is controlled by adjusting the width of the pulse signal (i.e., the duty cycle). Specifically, the output signal of the PWM module embedded in the main control board (or control board) is controlled to control the refrigerant flow of the expansion valve. The PWM-based refrigerant flow control replaces the continuous opening adjustment of the electronic expansion valve in related schemes with high-frequency switching control. By adjusting the duty cycle, the average flow of the expansion valve is controlled, preventing the valve core from remaining in the opening range that easily generates whistling and refrigerant flow noise, and directly skipping the resonance point to avoid vibration and whistling. Here, high-frequency switching control refers to a very fast switching control, controlling the average flow of the expansion valve by rapidly switching between on and off.

[0058] In the scheme of this invention, pressure-flow piecewise linearized control is adopted in the process of adjusting the duty cycle to control the average flow rate: the system operating range is divided into a high-pressure zone and a low-pressure zone, and each zone uses independent control parameters (independent control parameters refer to the initial duty cycle parameters) to avoid pressure surges caused by uniform control parameters; through a dynamic flow compensation algorithm, the PWM duty cycle is corrected in real time according to the superheat of the evaporator outlet to achieve coordinated control of refrigerant circulation and system pressure. Coordinated control of refrigerant circulation and system pressure involves dividing the system into high and low pressure zones based on the condenser side load, adjusting different initial duty cycles for different high and low pressure zones, with different duty cycles corresponding to different refrigerant circulation rates. The dynamic flow compensation algorithm quickly responds to pressure fluctuations, instantly suppresses pressure oscillations, and skips resonance points to avoid vibration and whistling sounds.

[0059] In some implementations, when the current mode is cooling mode, the condenser-side load of the air conditioner in the current mode is the outdoor ambient temperature of the air conditioner.

[0060] Step S120 determines the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode, including the process of determining the initial PWM duty cycle of the current mode in the cooling mode.

[0061] The following is combined with Figure 2 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for determining the initial PWM duty cycle in the current mode under the cooling mode. The specific process of determining the initial PWM duty cycle in the current mode under the cooling mode in step S120 is further explained, including steps S210 to S240.

[0062] Step S210: In cooling mode, determine whether the outdoor ambient temperature of the air conditioner is greater than or equal to the first set outer ring temperature, and determine whether the outdoor ambient temperature of the air conditioner is less than the second set outer ring temperature; wherein, the first set outer ring temperature is greater than the second set outer ring temperature, the first set outer ring temperature is such as 30°C, and the second set outer ring temperature is such as 25°C.

[0063] Step S220: In cooling mode, if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the first set outer ring temperature, then it is determined that the operating environment of the throttling device belongs to the first set cooling pressure zone, and the initial PWM duty cycle in the current mode is determined to be the first set cooling duty cycle; the first set cooling pressure zone is like the high pressure zone in cooling mode, and the first set cooling duty cycle is 60%.

[0064] Step S230: In cooling mode, if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the second set outer ring temperature and less than the first set outer ring temperature, then the initial PWM duty cycle of the current mode is determined to be the default duty cycle. That is, the opening degree of the throttling device is controlled to maintain the default opening degree, and the air conditioner is controlled to maintain the current operation (i.e., maintain the default mode operation). Maintaining the default mode, such as operating at the default duty cycle, is set to 45%.

[0065] Step S240: In cooling mode, if it is determined that the outdoor ambient temperature of the air conditioner is lower than the second set outer ring temperature, then it is determined that the operating environment of the throttling device belongs to the second set cooling pressure zone, and the initial PWM duty cycle of the current mode is determined to be the second set cooling duty cycle; wherein, the pressure of the second set cooling pressure zone is lower than the pressure of the first set cooling pressure zone, and the second set cooling duty cycle is lower than the first set cooling duty cycle. The second set cooling pressure zone is like the low-pressure zone in cooling mode, and the second set cooling duty cycle is 30%.

[0066] Figure 8 This is a schematic diagram of the control flow of an air conditioner noise reduction control method in cooling mode. Figure 8 As shown, the control flow of the air conditioner noise reduction control method in cooling mode includes:

[0067] Step 21: Turn on the air conditioner in cooling mode, then proceed to step 22.

[0068] Step 22: Detect the air conditioner load, such as the outdoor ambient temperature T_outer ring, to determine whether the expansion valve operates in a high-pressure or low-pressure zone. If the expansion valve operates in a high-pressure zone, proceed to step 23; if it operates in a low-pressure zone, proceed to step 24. Determining whether the expansion valve system is in a high-pressure or low-pressure zone is based on the condenser-side load. During cooling, the outdoor ambient temperature T_outer ring is used as the basis. Because the expansion valve acts as a throttling device, it is downstream of the condenser side in the refrigerant circulation; therefore, the division is based on the condenser-side load.

[0069] In step 22, it is specifically determined whether the outdoor ambient temperature T_outer ring is greater than or equal to 30℃ or less than 25℃: if the outdoor ambient temperature T_outer ring is greater than or equal to 30℃, proceed to step 23; if the outdoor ambient temperature T_outer ring is less than 25℃, proceed to step 24. Of course, if 25℃ ≤ outdoor ambient temperature T_outer ring < 30℃, the current control is maintained.

[0070] Step 23: When the outdoor ambient temperature T_outer ring is greater than or equal to 30℃, determine that the expansion valve is operating in a high-pressure zone, increase the duty cycle, and then proceed to step 25.

[0071] In step 23, when the air conditioner load is high (T outer ring ≥ 30℃) and the expansion valve system is in a high-pressure area, a larger refrigerant flow is needed to meet system operation requirements. Therefore, the PWM needs to be modified and the duty cycle increased to meet system operation needs. Specifically, within 15 minutes before the air conditioner starts in cooling mode, when the air conditioner load is high, the initial duty cycle N0 is set to 60%. Since the PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to pressure fluctuations caused by the increased opening degree and immediately suppress the whistling sound caused by pressure oscillation. In PWM mode, the output signal is controlled by adjusting the width of the pulse signal (i.e., the duty cycle), which controls the refrigerant flow of the expansion valve. The duty cycle means the proportion of the fully open time to the total time. A duty cycle of 100% means that the expansion is fully open throughout the entire process, and a duty cycle of 60% means that the full open time accounts for 60% and the full closed time accounts for 40%. The longer the full open time, the greater the flow rate, thereby adjusting the refrigerant flow rate.

[0072] Among them, PWM correction and increased duty cycle: When the expansion valve is fully open, the duty cycle is 100%. When the condensing side load is high, the initial duty cycle setting is too large because more refrigerant is required. For example, the duty cycle is 60% when the refrigeration is under high load, compared to 30% when the refrigeration is under low load. The duty cycle of 60% under high load is an increased duty cycle. The correction and increase here are relative to the low load.

[0073] PWM mode allows the valve core to switch rapidly between fully open and fully closed. When using PWM mode, the valve core switching cycle (e.g., 10 milliseconds ms) is much faster than the PID regulation in related solutions (measured in seconds in actual cases). The essential difference is the difference in regulation speed and regulation method. High-speed switching is the switching between fully open and fully closed, which is very fast. The control method of PID regulation in related solutions is to adjust the contact area between the valve needle and the valve port, change the volume of the refrigerant flow channel to control the flow rate. The valve needle action is continuous and the speed is relatively slow.

[0074] Step 24: When the outdoor ambient temperature T_outer ring is less than 25°C, determine that the expansion valve is operating in a low-pressure zone, reduce the duty cycle, and then proceed to step 25.

[0075] In step 24, when the air conditioner load is low (T outer ring < 25℃) and the expansion valve system is in the low-pressure area, since the room does not require much cooling output and the compressor generally operates at low frequency, if the PID control opening adjustment scheme in the relevant solution is used, the expansion valve opening response speed is slow, which can easily lead to energy waste. At the same time, the refrigerant flow noise (the sound of water droplets caused by the intermittent impact of refrigerant on the internal structure of the expansion valve) is transmitted to the room, causing discomfort. Therefore, pulse width modulation (PWM) refrigerant flow control is adopted. By correcting the PWM and reducing the duty cycle, the system operation is satisfied. That is, within 15 minutes before the air conditioner is turned on in cooling mode, when the air conditioner load is low, the initial duty cycle N0 is set to 30% to achieve fast response and solve the problem of abnormal refrigerant flow noise in the air conditioner under low load conditions.

[0076] Correcting PWM and reducing duty cycle: Corresponding to the high load above, the duty cycle is 100% when the expansion valve is fully open. When the condenser load is low, the initial duty cycle setting is relatively small because less refrigerant is required. For example, the duty cycle is 30% when the refrigeration is low load, compared to 60% when the refrigeration is high load. A duty cycle of 30% at low load means reducing the duty cycle. The correction and reduction here are relative to the high load.

[0077] The air conditioner load is determined based on the outdoor ambient temperature in the cooling mode. To determine whether the expansion valve system is in the high-pressure or low-pressure zone: it is based on the condenser-side load; during cooling, the outdoor ambient temperature is used as the basis; because the expansion valve acts as a throttling device, it is downstream of the condenser side in the refrigerant cycle, therefore the condenser-side load is used for classification.

[0078] The present invention provides an intelligent expansion valve system based on pulse width modulation (PWM). By adjusting the width of the pulse signal (i.e., the duty cycle), the output signal is controlled to control the refrigerant flow of the expansion valve. By adjusting the duty cycle, precise control of the expansion valve flow can be achieved.

[0079] In some implementations, when the current mode is cooling mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the cooling mode.

[0080] In step S150, the initial PWM duty cycle of the current mode is corrected according to the evaporator outlet superheat in the current mode to obtain the corrected PWM duty cycle of the current mode, including the process of correcting the initial PWM duty cycle of the current mode in the cooling mode.

[0081] The following is combined with Figure 3 The schematic diagram shows an embodiment of the method of the present invention for correcting the initial PWM duty cycle in the current mode under the cooling mode. It further illustrates the specific process of correcting the initial PWM duty cycle in the current mode under the cooling mode in step S150, including steps S310 to S340.

[0082] Step S310: In cooling mode, determine whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; wherein, in cooling mode, the target superheat in the current mode is the same as the target value in cooling mode.

[0083] Step S320: In cooling mode, if it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, the initial PWM duty cycle in the current mode is increased according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; in cooling mode, the set duty cycle increase method in the current mode is to correct the PWM duty cycle in real time by increasing the duty cycle by 1% / ms.

[0084] Step S330: In cooling mode, if it is determined that the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, then the initial PWM duty cycle in the current mode is maintained, that is, the initial PWM duty cycle in the current mode is used as the corrected PWM duty cycle in the current mode.

[0085] Step S340: In cooling mode, if it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, the initial PWM duty cycle in the current mode is increased according to the set duty cycle reduction method in the current mode to obtain the corrected PWM duty cycle in the current mode; in cooling mode, the set duty cycle reduction method in the current mode is used to correct the PWM duty cycle in real time by reducing the duty cycle by 1% / ms.

[0086] like Figure 8 As shown, the control flow of the air conditioner noise reduction control method in cooling mode also includes:

[0087] Step 25: While executing Step 23 or Step 24, obtain the superheat of the evaporator outlet in the air conditioner and determine whether the superheat of the evaporator outlet is higher than the target value. If it is determined that the superheat of the evaporator outlet is higher than the target value, execute Step 26 to increase the duty cycle. If it is determined that the superheat of the evaporator outlet is lower than the target value, execute Step 27 to decrease the duty cycle. Of course, if it is determined that the superheat of the evaporator outlet is equal to the target value, maintain the current control.

[0088] In step 25, during the pulse width modulation process, the PWM duty cycle is adjusted in real time according to the evaporator outlet superheat using a dynamic flow compensation algorithm. That is, after the air conditioner has been running for 15 minutes, the evaporator outlet superheat is acquired, and it is determined whether the evaporator outlet superheat is higher than the target value. If it is determined that the evaporator outlet superheat is higher than the target value, step 26 is executed to increase the duty cycle; if it is determined that the evaporator outlet superheat is lower than the target value, step 27 is executed to decrease the duty cycle.

[0089] Step 26: When the superheat at the evaporator outlet is higher than the target value, the PWM duty cycle is adjusted in real time by increasing the duty cycle by 1% / ms. By increasing the duty cycle, the refrigerant circulation is increased to reduce the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thus achieving coordinated control of refrigerant circulation and system pressure.

[0090] Step 27: When the superheat at the evaporator outlet is lower than the target value, the PWM duty cycle is adjusted in real time by reducing the duty cycle by 1% / ms. By reducing the duty cycle, the amount of refrigerant circulating is reduced to increase the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thereby achieving coordinated control of the refrigerant circulation and system pressure.

[0091] Because PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to system pressure fluctuations during the increase or decrease of the duty cycle. Therefore, it can solve the problem of fluid vibration and whistling noise caused by continuous adjustment of the expansion valve in related solutions. The adjustment of the duty cycle is calculated in milliseconds, so the adjustment and switching speed is very fast. The process of controlling the flow rate by the proportion of the valve core's fully open and fully closed states is the process of the valve core switching rapidly between fully open and fully closed states. When using PWM mode, the valve core switching cycle (e.g., 1ms) is much faster than traditional PID regulation (measured in seconds in actual cases). The essential difference is the difference in adjustment speed and adjustment method. High-speed switching is the switching between fully open and fully closed states, which is very fast. The conventional control method is to adjust the contact area between the valve needle and the valve port to change the volume of the refrigerant flow channel to control the flow rate. The valve needle action is continuous and the speed is relatively slow.

[0092] In cooling mode, there are corresponding relationships between the compressor's suction temperature, system pressure, saturation temperature, and superheat under different outdoor and indoor ambient temperatures. These relationships can be referenced. Figure 10 The example shown. Figure 10 Table 1 shows the relationship between temperature and pressure in air conditioner cooling mode. The outdoor ambient temperature, indoor ambient temperature, and compressor suction temperature are detected by the air conditioner's temperature sensor. The system pressure is detected by a pressure sensor. The saturation temperature is calculated by coupling the system pressure and suction temperature (this can be done using pressure and temperature lookup software). The evaporator outlet superheat is calculated as suction temperature minus the corresponding saturation temperature. System pressure refers to suction pressure or evaporation pressure.

[0093] The table showing the relationship between temperature and pressure in cooling mode is as follows: Figure 10 Table 1 is shown below. For example: Figure 10 As shown in one example, in cooling mode, the outer ring temperature (i.e., outdoor ambient temperature) is 20°C, the compressor suction temperature is 3.5°C, the compressor suction pressure is 0.75 MPa, the saturation temperature corresponding to the compressor suction pressure is 1.502°C, and the evaporator outlet superheat is 1.998°C.

[0094] In the solution of this invention, when controlling the refrigerant flow of the expansion valve, pressure-flow segmented linearization control is used: the system operating range is divided into a high-pressure zone and a low-pressure zone, and each zone adopts independent control parameters. Through a dynamic flow compensation algorithm, the PWM duty cycle is corrected in real time according to the superheat of the evaporator outlet, so as to achieve coordinated control of refrigerant circulation and system pressure; by quickly responding to pressure fluctuations and suppressing pressure oscillations in real time, the problem of expansion valve whistling is solved.

[0095] In some implementations, when the current mode is heating mode, the condenser-side load of the air conditioner in the current mode is the indoor ambient temperature of the air conditioner.

[0096] Step S120, which determines the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode, also includes the process of determining the initial PWM duty cycle of the current mode in the heating mode.

[0097] The following is combined with Figure 4 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for determining the initial PWM duty cycle in the current mode under the heating mode. The specific process of determining the initial PWM duty cycle in the current mode under the heating mode in step S120 is further explained, including steps S410 to S440.

[0098] Step S410: In heating mode, determine whether the indoor ambient temperature of the air conditioner is greater than or equal to the first set inner ring temperature, and determine whether the indoor ambient temperature of the air conditioner is less than the second set inner ring temperature; wherein, the first set inner ring temperature is greater than the second set inner ring temperature, the first set inner ring temperature is such as 20℃, and the second set inner ring temperature is such as 10℃.

[0099] Step S420: In heating mode, if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the first set inner ring temperature, then it is determined that the operating environment of the throttling device belongs to the first set heating pressure zone, and the initial PWM duty cycle of the current mode is determined to be the first set heating duty cycle; the first set heating pressure zone is like the high pressure zone in the heating mode, and the first set heating duty cycle is 50%.

[0100] Step S430: In heating mode, if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the second set inner ring temperature and less than the first set inner ring temperature, then the initial PWM duty cycle of the current mode is determined to be the default duty cycle, that is, the opening degree of the throttling device is controlled to maintain the default opening degree, and the air conditioner is controlled to maintain the current operation (i.e., maintain the default mode operation).

[0101] Step S440: In heating mode, if it is determined that the indoor ambient temperature of the air conditioner is lower than the second set inner ring temperature, then it is determined that the operating environment of the throttling device belongs to the second set heating pressure zone, and the initial PWM duty cycle of the current mode is determined to be the second set heating duty cycle; wherein, the pressure of the second set heating pressure zone is lower than the pressure of the first set heating pressure zone, and the second set heating duty cycle is lower than the first set heating duty cycle. The second set heating pressure zone is like the low-pressure zone in heating mode, and the second set heating duty cycle is 20%.

[0102] Figure 9 This is a schematic diagram of the control flow of an air conditioner noise reduction control method in heating mode. Figure 9 As shown, the control flow of the air conditioner noise reduction control method in heating mode includes:

[0103] Step 31: Turn on the air conditioner in heating mode, then proceed to step 32.

[0104] Step 32: Detect the air conditioner load, such as the indoor ambient temperature T (inner loop), to determine whether the expansion valve operating environment is in a high-pressure or low-pressure zone. If the expansion valve operating environment is determined to be in a high-pressure zone, proceed to step 33; if the expansion valve operating environment is determined to be in a low-pressure zone, proceed to step 34. Determining whether the expansion valve system is in a high-pressure or low-pressure zone is based on the condenser-side load. During heating, the indoor ambient temperature T (inner loop) is used as the basis. Because the expansion valve acts as a throttling device, it is downstream of the condenser side in the refrigerant circulation; therefore, the division is based on the condenser-side load.

[0105] In step 32, it is specifically determined whether the indoor ambient temperature T_inner ring is greater than or equal to 20℃ or less than 10℃: if the indoor ambient temperature T_inner ring is greater than or equal to 20℃, proceed to step 33; if the indoor ambient temperature T_inner ring is less than 10℃, proceed to step 34. Of course, if 10℃ ≤ indoor ambient temperature T_inner ring < 20℃, the current control is maintained.

[0106] Step 33: When the indoor ambient temperature T inner ring is greater than or equal to 20℃, it is determined that the expansion valve is operating in a high-pressure zone. The duty cycle is increased, and then step 35 is executed.

[0107] In step 33, when the air conditioner load is high (T inner ring ≥ 20℃) and the expansion valve system is in the high-pressure area, more refrigerant flow needs to be compensated to meet the system operation. Therefore, it is necessary to modify the PWM and increase the duty cycle to meet this requirement. That is, in the first 15 minutes before the heating mode is turned on, when the air conditioner load is high, the initial duty cycle N0 is set to 50%. Similar to the cooling mode, this is relative to the low-pressure area. Relative to the low-pressure area, it means increasing the duty cycle to increase the refrigerant flow. Since the PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to the pressure fluctuations caused by the increase in opening degree and immediately suppress the whistling sound caused by pressure oscillation.

[0108] Step 34: When the indoor ambient temperature T inner ring is less than 10℃, it is determined that the expansion valve is operating in a low-pressure zone. The duty cycle is reduced, and then step 35 is executed.

[0109] In step 34, when the air conditioner load is low (T inner ring < 10℃) and the expansion valve system is in the low-pressure area, it is necessary to quickly reduce the refrigerant circulation volume and increase the exhaust temperature to meet the room's heating requirements. If the PID control opening adjustment scheme in the relevant solution is used, the expansion valve opening response speed is slow, the outlet air temperature is low, and the comfort is poor. At the same time, the refrigerant flow noise (the sound of water droplets caused by the intermittent impact of refrigerant on the internal structure of the expansion valve) is transmitted to the room, causing discomfort. Therefore, pulse width modulation (PWM) refrigerant flow control is adopted. By correcting the PWM and reducing the duty cycle, in the first 15 minutes of the heating mode, when the air conditioner load is low, the initial duty cycle N0 is set to 20%. Similar to the cooling mode, this is relative to the high-pressure area. Relative to the high-pressure area, it means reducing the duty cycle and reducing the refrigerant volume to achieve a fast response and solve the problem of abnormal refrigerant flow noise in the air conditioner under low load conditions.

[0110] The heating mode determines the air conditioner load based on the indoor ambient temperature. Determining whether the expansion valve system is in a high-pressure or low-pressure zone is based on the condenser-side load. During heating, the indoor ambient temperature is used as the basis; because the expansion valve acts as a throttling device and is downstream of the condenser side in the refrigerant circulation, the condenser-side load is used for classification. During cooling, the outer side is the condenser side, so the outdoor ambient temperature is used as the basis; during heating, the inner side is the condenser side, so the indoor ambient temperature is used as the basis. Essentially, it's based on the condenser-side load. High and low pressure zones are defined by load; a high condenser-side load defines a high-pressure zone, and a low condenser-side load defines a low-pressure zone. Because the expansion valve acts as a throttling device and is downstream of the condenser side in the refrigerant circulation, the condenser-side load is used for classification. This ensures a true reflection of the refrigerant pressure entering the expansion valve.

[0111] In the solution of this invention, an intelligent expansion valve system based on pulse width modulation (PWM) is adopted. The output signal is controlled by adjusting the width of the pulse signal (i.e., the duty cycle), thereby controlling the refrigerant flow of the expansion valve. This solves the problem of inaccurate flow control of the expansion valve in related solutions, achieves fast and accurate flow control, and achieves the effect of low power consumption and high efficiency.

[0112] In some implementations, when the current mode is heating mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the heating mode.

[0113] Step S150 includes correcting the initial PWM duty cycle of the current mode based on the evaporator outlet superheat in the current mode to obtain the corrected PWM duty cycle of the current mode. It also includes the process of correcting the initial PWM duty cycle of the current mode in the heating mode.

[0114] The following is combined with Figure 5The schematic diagram shows an embodiment of the method of the present invention for correcting the initial PWM duty cycle in the current mode under the heating mode. It further illustrates the specific process of correcting the initial PWM duty cycle in the current mode under the heating mode in step S150, including steps S510 to S540.

[0115] Step S510: In heating mode, determine whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; wherein, in heating mode, the target superheat in the current mode is the target value in heating mode.

[0116] Step S520: In heating mode, if it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, the initial PWM duty cycle in the current mode is increased according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; in heating mode, the set duty cycle increase method in the current mode is to correct the PWM duty cycle in real time by increasing the duty cycle by 1% / ms.

[0117] Step S530: In heating mode, if it is determined that the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, then the initial PWM duty cycle in the current mode is maintained, that is, the initial PWM duty cycle in the current mode is used as the corrected PWM duty cycle in the current mode.

[0118] Step S540: In heating mode, if it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, the initial PWM duty cycle in the current mode is increased according to the set duty cycle reduction method in the current mode to obtain the corrected PWM duty cycle in the current mode; in heating mode, the set duty cycle reduction method in the current mode is used to correct the PWM duty cycle in real time by reducing the duty cycle by 1% / ms.

[0119] like Figure 9 As shown, the control flow of the air conditioner noise reduction control method in heating mode also includes:

[0120] Step 35: While executing step 33 or step 34, obtain the superheat of the evaporator outlet in the air conditioner and determine whether the superheat of the evaporator outlet is higher than the target value: if it is determined that the superheat of the evaporator outlet is higher than the target value, execute step 36 to increase the duty cycle; if it is determined that the superheat of the evaporator outlet is lower than the target value, execute step 37 to decrease the duty cycle; of course, if it is determined that the superheat of the evaporator outlet is equal to the target value, maintain the current control.

[0121] In step 35, during the pulse width modulation process, the PWM duty cycle is adjusted in real time according to the evaporator outlet superheat using a dynamic flow compensation algorithm. That is, after the air conditioner has been running for 15 minutes, the evaporator outlet superheat is acquired, and it is determined whether the evaporator outlet superheat is higher than the target value. If it is determined that the evaporator outlet superheat is higher than the target value, step 36 is executed to increase the duty cycle; if it is determined that the evaporator outlet superheat is lower than the target value, step 37 is executed to decrease the duty cycle.

[0122] Step 36: When the superheat at the evaporator outlet is higher than the target value, the PWM duty cycle is adjusted in real time by increasing the duty cycle by 1% / ms. By increasing the duty cycle, the refrigerant circulation is increased to reduce the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thus achieving coordinated control of refrigerant circulation and system pressure.

[0123] Step 37: When the superheat at the evaporator outlet is lower than the target value, the PWM duty cycle is adjusted in real time by reducing the duty cycle by 1% / ms. By reducing the duty cycle, the amount of refrigerant circulating is reduced to increase the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thereby achieving coordinated control of the refrigerant circulation and system pressure.

[0124] Since PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to system pressure fluctuations during the increase or decrease of the duty cycle. Therefore, it can solve the problem of whistling noise such as fluid vibration caused by continuous adjustment of the expansion valve in related solutions.

[0125] In heating mode, there are corresponding relationships between the compressor's suction temperature, system pressure, saturation temperature, and superheat under different outdoor and indoor ambient temperatures. These relationships can be referenced. Figure 11 The example shown. Figure 11 Table 2 shows the relationship between temperature and pressure in air conditioner cooling mode. The outdoor ambient temperature, indoor ambient temperature, and compressor suction temperature are detected by the air conditioner's temperature sensor. The system pressure is detected by a pressure sensor. The saturation temperature is calculated by coupling the system pressure and suction temperature (this can be done using pressure and temperature lookup software). The evaporator outlet superheat is calculated as suction temperature minus the corresponding saturation temperature. System pressure refers to suction pressure or evaporation pressure.

[0126] The table showing the relationship between temperature and pressure in heating mode is as follows: Figure 11 Table 1 is shown below. For example: Figure 11 As shown in one example, in heating mode, the inner ring temperature (i.e., the indoor ambient temperature) is 20°C, the compressor suction temperature is -5°C, the compressor suction pressure is 0.55MPa, the saturation temperature corresponding to the compressor suction pressure is -6.66°C, and the evaporator outlet superheat is 1.669°C.

[0127] In the present invention, the refrigerant flow control method of the intelligent expansion valve system based on pulse width modulation (PWM) is as follows: the continuous opening adjustment of the electronic expansion valve in related solutions is replaced with high-frequency switching control. By adjusting the duty cycle, the average flow rate is controlled, avoiding the valve core of the expansion valve from remaining in the opening range that is prone to whistling and refrigerant flow noise, and directly skipping the resonance point to avoid vibration and whistling. The refrigerant flow control using pulse width modulation (PWM) is achieved through high-frequency switching, resulting in low power consumption and high efficiency.

[0128] In the solution of this invention, a dynamic flow compensation algorithm is used to quickly respond to pressure fluctuations and instantly suppress pressure oscillations, thus solving the whistling sound problem caused by expansion valve control in related solutions and achieving the effect of suppressing pressure oscillations. By suppressing pressure oscillations, the resonance point is skipped to avoid generating vibration whistling sound.

[0129] In this invention, the opening of the expansion valve is controlled using PWM mode. Pulse Width Modulation (PWM) controls refrigerant flow through high-frequency switching, resulting in low power consumption and high efficiency. By adjusting the duty cycle, precise control of the expansion valve flow can be achieved. PWM controls the output signal by adjusting the width of the pulse signal (i.e., the duty cycle). The duty cycle represents the proportion of the fully open time to the total time; a longer fully open time results in a larger flow rate, thus regulating the refrigerant flow. Because the fully open / fully closed adjustment speed is very fast, it is described as a high-frequency switch. In related solutions, the expansion valve gradually adjusts its opening using a stepper motor, while the PWM mode allows the valve core to switch rapidly between fully open and fully closed (e.g., 100 times / second). By adjusting the proportion of the fully open time (duty cycle), the average refrigerant flow is controlled, providing a rapid response to pressure fluctuations. The switching cycle of PWM (e.g., 10ms) is much faster than the PID regulation in related solutions (over 200ms), which can instantly suppress pressure oscillations. Pulse Width Modulation (PWM) refrigerant flow control replaces continuous adjustment with high-frequency switching, offering advantages such as fast response, low cost, and ease of implementation. It represents an innovative breakthrough in solving expansion valve whistling. The solution provided in this invention is a PWM regulation control flowchart. Conventional PID control adjusts the opening based on the target exhaust gas level; if the exhaust gas level is higher than the target, the opening is increased; if it is lower, the opening is decreased, until it falls within the exhaust gas tolerance range required by the program.

[0130] The technical solution of this embodiment involves detecting the condenser-side load (e.g., outdoor ambient temperature in cooling mode or indoor ambient temperature in heating mode) of the air conditioner when it is turned on and running in the current mode (e.g., cooling mode or heating mode) and targeting the throttling device (e.g., expansion valve) in the air conditioner. Based on the level of the condenser-side load, it is determined whether the operating environment of the expansion valve belongs to a first pressure zone (e.g., high pressure zone) or a second pressure zone (e.g., low pressure zone). If the operating environment of the expansion valve belongs to the high pressure zone, the first duty cycle of the current mode (e.g., the higher duty cycle of the current mode) is used as the initial duty cycle to control the opening degree of the expansion valve. If the expansion valve's... If the operating environment is in a low-pressure zone, the second duty cycle of the current mode (such as the lower duty cycle of the current mode) is used as the initial duty cycle to control the opening of the expansion valve. After the first set time (such as 15 minutes), the superheat of the evaporator outlet in the current mode is detected. The initial duty cycle of the current mode is corrected based on the superheat of the evaporator outlet in the current mode to obtain the corrected duty cycle, and the opening of the expansion valve is controlled according to the corrected duty cycle of the current mode. Thus, by using PWM mode to control the opening of the expansion valve, and combining the condenser side load of the air conditioner and the superheat of the evaporator outlet to determine the PWM duty cycle, the flow rate of the expansion valve can be precisely controlled, noise can be reduced, and the user experience can be improved.

[0131] According to an embodiment of the present invention, a control device for an air conditioner corresponding to the control method for an air conditioner is also provided. See also Figure 6 The diagram shows a structural schematic of an embodiment of the device of the present invention. The air conditioner has a throttling device, the opening degree of which can be controlled according to a preset PWM mode, that is, the opening degree of the throttling device can be controlled by adjusting the PWM duty cycle; of course, the air conditioner also has an outdoor heat exchanger, an indoor heat exchanger, and a compressor, etc., and the throttling device is such as an expansion valve; in the current mode of the air conditioner, one of the outdoor heat exchanger and the indoor heat exchanger is a condenser, and the other heat exchanger is an evaporator; in the solution of the present invention, as... Figure 6 As shown, the control device of the air conditioner includes: an acquisition unit 102 and a control unit 104.

[0132] The acquisition unit 102 is configured to acquire the condenser-side load of the air conditioner in the current mode when the air conditioner is turned on and running in the current mode. The specific functions and processing of the acquisition unit 102 are described in step S110.

[0133] The control unit 104 is configured to determine the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode. The specific functions and processing of the control unit 104 are described in step S110.

[0134] The control unit 104 is also configured to control the opening degree of the throttling device according to the initial PWM duty cycle in the current mode. The specific functions and processing of the control unit 104 are further described in step S130.

[0135] The acquisition unit 102 is further configured to acquire the evaporator outlet superheat in the air conditioner under the current mode after the air conditioner controls the opening degree of the throttling device for a first set time according to the initial PWM duty cycle of the current mode. The specific functions and processing of the acquisition unit 102 are further described in step S140.

[0136] The control unit 104 is further configured to correct the initial PWM duty cycle of the current mode based on the evaporator outlet superheat in the current mode, thereby obtaining the corrected PWM duty cycle in the current mode. The specific functions and processing of this control unit 104 are further described in step S150.

[0137] The control unit 104 is also configured to adjust the opening of the throttling device according to the modified PWM duty cycle in the current mode, so as to precisely control the flow rate of the expansion valve and reduce noise. The specific functions and processing of the control unit 104 are further described in step S160.

[0138] The present invention proposes an air conditioner noise reduction control scheme based on a pulse width modulation (PWM) intelligent expansion valve system. By adjusting the duty cycle, the flow rate of the expansion valve can be precisely controlled. Through a dynamic flow compensation algorithm, pressure oscillation is suppressed, resonance points are skipped to avoid vibration and howling, thus reducing noise and improving user experience.

[0139] In some implementations, the current mode includes: a cooling mode and a heating mode.

[0140] The acquisition unit 102 acquires the condenser-side load of the air conditioner in the current mode, including:

[0141] The acquisition unit 102 is further configured to acquire the outdoor ambient temperature of the air conditioner when the current mode is cooling mode, and use it as the condenser-side load of the air conditioner in cooling mode; the outdoor ambient temperature of the air conditioner is like the outdoor ambient temperature T outer ring.

[0142] The acquisition unit 102 is further configured to acquire the indoor ambient temperature of the air conditioner when the current mode is heating mode, and use this as the condensing-side load of the air conditioner in heating mode. The indoor ambient temperature of the air conditioner is the same as the outdoor ambient temperature T_inner ring.

[0143] Figure 7 This is a schematic diagram of the overall control flow of a noise reduction control method for an air conditioner. Figure 7As shown, the overall control flow of the air conditioner noise reduction control method includes:

[0144] Step 11: Detect and report the room load status, then proceed to step 12.

[0145] Step 12: Determine whether the expansion valve operates in a high-pressure or low-pressure zone, then proceed to Step 13. The system's operating range is divided into high-pressure and low-pressure zones based on the condenser-side load; during cooling, the outdoor ambient temperature is used as the basis, and during heating, the indoor ambient temperature is used. The high-pressure and low-pressure zones are defined by the load: a high condenser-side load defines the high-pressure zone, and a low condenser-side load defines the low-pressure zone.

[0146] Step 13: Obtain the evaporator outlet superheat, and then proceed to step 14.

[0147] Step 14: Correct the PWM duty cycle in real time according to the dynamic flow compensation algorithm. The duty cycle represents the proportion of the valve core fully open period to the total period, ranging from 0% to 100%, and is represented by the letter N.

[0148] In the noise reduction control scheme for an air conditioner proposed in this invention, the air conditioner control board embeds a pulse width modulation (PWM) module. Based on the intelligent expansion valve system of pulse width modulation (PWM), the output signal is controlled by adjusting the width of the pulse signal (i.e., the duty cycle), thereby controlling the refrigerant flow of the expansion valve. The pulse width modulation (PWM) refrigerant flow control changes the continuous opening adjustment of the electronic expansion valve in related schemes to high-frequency switching control. By adjusting the duty cycle, the average flow is controlled, avoiding the valve core from staying in the opening range that is prone to whistling and refrigerant flow noise, and directly skipping the resonance point to avoid generating vibration whistling.

[0149] In the scheme of this invention, pressure-flow piecewise linearized control is adopted in the process of adjusting the duty cycle to control the average flow rate: the system operating range is divided into a high-pressure zone and a low-pressure zone, and each zone uses independent control parameters (independent control parameters refer to the initial duty cycle parameters) to avoid pressure surges caused by uniform control parameters; through a dynamic flow compensation algorithm, the PWM duty cycle is corrected in real time according to the superheat of the evaporator outlet to achieve coordinated control of refrigerant circulation and system pressure. Coordinated control of refrigerant circulation and system pressure involves dividing the system into high and low pressure zones based on the condenser side load, adjusting different initial duty cycles for different high and low pressure zones, with different duty cycles corresponding to different refrigerant circulation rates. The dynamic flow compensation algorithm quickly responds to pressure fluctuations, instantly suppresses pressure oscillations, and skips resonance points to avoid vibration and whistling sounds.

[0150] In some implementations, when the current mode is cooling mode, the condenser-side load of the air conditioner in the current mode is the outdoor ambient temperature of the air conditioner.

[0151] The control unit 104 determines the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode, including the process of determining the initial PWM duty cycle of the current mode in cooling mode, as follows:

[0152] The control unit 104 is further configured to, in cooling mode, determine whether the outdoor ambient temperature of the air conditioner is greater than or equal to a first set outer ring temperature, and whether the outdoor ambient temperature of the air conditioner is less than a second set outer ring temperature; wherein, the first set outer ring temperature is greater than the second set outer ring temperature, for example, the first set outer ring temperature is 30°C, and the second set outer ring temperature is for example, 25°C. The specific functions and processing of the control unit 104 are further described in step S210.

[0153] The control unit 104 is further configured to, in cooling mode, if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to a first set outer ring temperature, determine that the operating environment of the throttling device belongs to a first set cooling pressure zone, and determine the initial PWM duty cycle of the current mode as the first set cooling duty cycle; the first set cooling pressure zone is like the high-pressure zone in cooling mode, and the first set cooling duty cycle is 60%. The specific functions and processing of the control unit 104 are further described in step S220.

[0154] The control unit 104 is further configured to, in cooling mode, if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the second set outer ring temperature and less than the first set outer ring temperature, then determine the initial PWM duty cycle of the current mode as the default duty cycle, that is, control the opening degree of the throttling device to maintain the default opening degree, and control the air conditioner to maintain the current operation (i.e., maintain the default mode operation). The specific functions and processing of this control unit 104 are further described in step S230.

[0155] The control unit 104 is further configured to, in cooling mode, if it is determined that the outdoor ambient temperature of the air conditioner is lower than the second set outer ring temperature, determine that the operating environment of the throttling device belongs to the second set cooling pressure zone, and determine the initial PWM duty cycle of the current mode as the second set cooling duty cycle; wherein, the pressure of the second set cooling pressure zone is lower than the pressure of the first set cooling pressure zone, and the second set cooling duty cycle is lower than the first set cooling duty cycle. The second set cooling pressure zone is like the low-pressure zone in cooling mode, and the second set cooling duty cycle is 30%. The specific functions and processing of this control unit 104 are further described in step S240.

[0156] Figure 8 This is a schematic diagram of the control flow of an air conditioner noise reduction control method in cooling mode. Figure 8 As shown, the control flow of the air conditioner noise reduction control method in cooling mode includes:

[0157] Step 21: Turn on the air conditioner in cooling mode, then proceed to step 22.

[0158] Step 22: Detect the air conditioner load, such as the outdoor ambient temperature T_outer ring, to determine whether the expansion valve operates in a high-pressure or low-pressure zone. If the expansion valve operates in a high-pressure zone, proceed to step 23; if it operates in a low-pressure zone, proceed to step 24. Determining whether the expansion valve system is in a high-pressure or low-pressure zone is based on the condenser-side load. During cooling, the outdoor ambient temperature T_outer ring is used as the basis. Because the expansion valve acts as a throttling device, it is downstream of the condenser side in the refrigerant circulation; therefore, the division is based on the condenser-side load.

[0159] In step 22, it is specifically determined whether the outdoor ambient temperature T_outer ring is greater than or equal to 30℃ or less than 25℃: if the outdoor ambient temperature T_outer ring is greater than or equal to 30℃, proceed to step 23; if the outdoor ambient temperature T_outer ring is less than 25℃, proceed to step 24. Of course, if 25℃ ≤ outdoor ambient temperature T_outer ring < 30℃, the current control is maintained.

[0160] Step 23: When the outdoor ambient temperature T_outer ring is greater than or equal to 30℃, determine that the expansion valve is operating in a high-pressure zone, increase the duty cycle, and then proceed to step 25.

[0161] In step 23, when the air conditioner load is high (T outer ring ≥ 30℃) and the expansion valve system is in the high pressure area, more refrigerant flow needs to be compensated to meet the system operation. Therefore, it is necessary to modify the PWM and increase the duty cycle to meet the system operation. That is, within 15 minutes before the air conditioner is turned on in cooling mode, when the air conditioner load is high, the initial duty cycle N0 is set to 60%. Since the PWM mode allows the valve core to switch between fully open and fully closed at high speed, it can quickly respond to the pressure fluctuations caused by the increase in opening degree and immediately suppress the whistling sound caused by pressure oscillation.

[0162] Among them, PWM correction and increased duty cycle: When the expansion valve is fully open, the duty cycle is 100%. When the condensing side load is high, the initial duty cycle setting is too large because more refrigerant is required. For example, the duty cycle is 60% when the refrigeration is under high load, compared to 30% when the refrigeration is under low load. The duty cycle of 60% under high load is an increased duty cycle. The correction and increase here are relative to the low load.

[0163] PWM mode allows the valve core to switch rapidly between fully open and fully closed. When using PWM mode, the valve core switching cycle (e.g., 10 milliseconds ms) is much faster than the PID regulation in related solutions (measured in seconds in actual cases). The essential difference is the difference in regulation speed and regulation method. High-speed switching is the switching between fully open and fully closed, which is very fast. The control method of PID regulation in related solutions is to adjust the contact area between the valve needle and the valve port, change the volume of the refrigerant flow channel to control the flow rate. The valve needle action is continuous and the speed is relatively slow.

[0164] Step 24: When the outdoor ambient temperature T_outer ring is less than 25°C, determine that the expansion valve is operating in a low-pressure zone, reduce the duty cycle, and then proceed to step 25.

[0165] In step 24, when the air conditioner load is low (T outer ring < 25℃) and the expansion valve system is in the low-pressure area, since the room does not require much cooling output and the compressor generally operates at low frequency, if the PID control opening adjustment scheme in the relevant solution is used, the expansion valve opening response speed is slow, which can easily lead to energy waste. At the same time, the refrigerant flow noise (the sound of water droplets caused by the intermittent impact of refrigerant on the internal structure of the expansion valve) is transmitted to the room, causing discomfort. Therefore, pulse width modulation (PWM) refrigerant flow control is adopted. By correcting the PWM and reducing the duty cycle, the system operation is satisfied. That is, within 15 minutes before the air conditioner is turned on in cooling mode, when the air conditioner load is low, the initial duty cycle N0 is set to 30% to achieve fast response and solve the problem of abnormal refrigerant flow noise in the air conditioner under low load conditions.

[0166] Correcting PWM and reducing duty cycle: Corresponding to the high load above, the duty cycle is 100% when the expansion valve is fully open. When the condenser load is low, the initial duty cycle setting is relatively small because less refrigerant is required. For example, the duty cycle is 30% when the refrigeration is low load, compared to 60% when the refrigeration is high load. A duty cycle of 30% at low load means reducing the duty cycle. The correction and reduction here are relative to the high load.

[0167] The air conditioner load is determined based on the outdoor ambient temperature in the cooling mode. To determine whether the expansion valve system is in the high-pressure or low-pressure zone: it is based on the condenser-side load; during cooling, the outdoor ambient temperature is used as the basis; because the expansion valve acts as a throttling device, it is downstream of the condenser side in the refrigerant cycle, therefore the condenser-side load is used for classification.

[0168] The present invention provides an intelligent expansion valve system based on pulse width modulation (PWM). By adjusting the width of the pulse signal (i.e., the duty cycle), the output signal is controlled to control the refrigerant flow of the expansion valve. By adjusting the duty cycle, precise control of the expansion valve flow can be achieved.

[0169] In some implementations, when the current mode is cooling mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the cooling mode.

[0170] The control unit 104 corrects the initial PWM duty cycle of the current mode based on the evaporator outlet superheat in the current mode, to obtain the corrected PWM duty cycle of the current mode. This includes the process of correcting the initial PWM duty cycle of the current mode in the cooling mode, as detailed below:

[0171] The control unit 104 is further configured to determine, in cooling mode, whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; wherein, in cooling mode, the target superheat in the current mode is the target value in cooling mode. The specific functions and processing of this control unit 104 are further described in step S310.

[0172] The control unit 104 is further configured to, in cooling mode, if it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, increase the initial PWM duty cycle in the current mode according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; in cooling mode, the set duty cycle increase method in the current mode is used to correct the PWM duty cycle in real time, such as by increasing the duty cycle by 1% / ms. The specific functions and processing of this control unit 104 are further described in step S320.

[0173] The control unit 104 is further configured to, in cooling mode, if it is determined that the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, maintain the initial PWM duty cycle in the current mode, that is, use the initial PWM duty cycle in the current mode as the corrected PWM duty cycle in the current mode. The specific functions and processing of this control unit 104 are further described in step S330.

[0174] The control unit 104 is further configured to, in cooling mode, if it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, increase the initial PWM duty cycle in the current mode according to the set duty cycle reduction method in the current mode to obtain the corrected PWM duty cycle in the current mode; in cooling mode, the set duty cycle reduction method in the current mode is used to correct the PWM duty cycle in real time, such as by reducing the duty cycle by 1% / ms. The specific functions and processing of this control unit 104 are further described in step S340.

[0175] like Figure 8 As shown, the control flow of the air conditioner noise reduction control method in cooling mode also includes:

[0176] Step 25: While executing Step 23 or Step 24, obtain the superheat of the evaporator outlet in the air conditioner and determine whether the superheat of the evaporator outlet is higher than the target value. If it is determined that the superheat of the evaporator outlet is higher than the target value, execute Step 26 to increase the duty cycle. If it is determined that the superheat of the evaporator outlet is lower than the target value, execute Step 27 to decrease the duty cycle. Of course, if it is determined that the superheat of the evaporator outlet is equal to the target value, maintain the current control.

[0177] In step 25, during the pulse width modulation process, the PWM duty cycle is adjusted in real time according to the evaporator outlet superheat using a dynamic flow compensation algorithm. That is, after the air conditioner has been running for 15 minutes, the evaporator outlet superheat is acquired, and it is determined whether the evaporator outlet superheat is higher than the target value. If it is determined that the evaporator outlet superheat is higher than the target value, step 26 is executed to increase the duty cycle; if it is determined that the evaporator outlet superheat is lower than the target value, step 27 is executed to decrease the duty cycle.

[0178] Step 26: When the superheat at the evaporator outlet is higher than the target value, the PWM duty cycle is adjusted in real time by increasing the duty cycle by 1% / ms. By increasing the duty cycle, the refrigerant circulation is increased to reduce the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thus achieving coordinated control of refrigerant circulation and system pressure.

[0179] Step 27: When the superheat at the evaporator outlet is lower than the target value, the PWM duty cycle is adjusted in real time by reducing the duty cycle by 1% / ms. By reducing the duty cycle, the amount of refrigerant circulating is reduced to increase the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thereby achieving coordinated control of the refrigerant circulation and system pressure.

[0180] Since PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to system pressure fluctuations during the increase or decrease of the duty cycle. Therefore, it can solve the problem of whistling noise such as fluid vibration caused by continuous adjustment of the expansion valve in related solutions.

[0181] In cooling mode, there are corresponding relationships between the compressor's suction temperature, system pressure, saturation temperature, and superheat under different outdoor and indoor ambient temperatures. These relationships can be referenced. Figure 10 The example shown. Figure 10 Table 1 shows the relationship between temperature and pressure in air conditioner cooling mode. The outdoor ambient temperature, indoor ambient temperature, and compressor suction temperature are detected by the air conditioner's temperature sensor. The system pressure is detected by a pressure sensor. The saturation temperature is calculated by coupling the system pressure and suction temperature (this can be done using pressure and temperature lookup software). The evaporator outlet superheat is calculated as suction temperature minus the corresponding saturation temperature. System pressure refers to suction pressure or evaporation pressure.

[0182] The table showing the relationship between temperature and pressure in cooling mode is as follows: Figure 10 Table 1 is shown below. For example: Figure 10 As shown in one example, in cooling mode, the outer ring temperature (i.e., outdoor ambient temperature) is 20°C, the compressor suction temperature is 3.5°C, the compressor suction pressure is 0.75 MPa, the saturation temperature corresponding to the compressor suction pressure is 1.502°C, and the evaporator outlet superheat is 1.998°C.

[0183] In the solution of this invention, when controlling the refrigerant flow of the expansion valve, pressure-flow segmented linearization control is used: the system operating range is divided into a high-pressure zone and a low-pressure zone, and each zone adopts independent control parameters. Through a dynamic flow compensation algorithm, the PWM duty cycle is corrected in real time according to the superheat of the evaporator outlet, so as to achieve coordinated control of refrigerant circulation and system pressure; by quickly responding to pressure fluctuations and suppressing pressure oscillations in real time, the problem of expansion valve whistling is solved.

[0184] In some implementations, when the current mode is heating mode, the condenser-side load of the air conditioner in the current mode is the indoor ambient temperature of the air conditioner.

[0185] The control unit 104 determines the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode. The process of determining the initial PWM duty cycle in the heating mode is as follows:

[0186] The control unit 104 is further configured to, in heating mode, determine whether the indoor ambient temperature of the air conditioner is greater than or equal to a first set inner ring temperature, and whether the indoor ambient temperature of the air conditioner is less than a second set inner ring temperature; wherein, the first set inner ring temperature is greater than the second set inner ring temperature, for example, the first set inner ring temperature is 20°C, and the second set inner ring temperature is for example, 10°C. The specific functions and processing of the control unit 104 are further described in step S410.

[0187] The control unit 104 is further configured to, in heating mode, if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to a first set inner ring temperature, determine that the operating environment of the throttling device belongs to a first set heating pressure zone, and determine the initial PWM duty cycle of the current mode as the first set heating duty cycle; the first set heating pressure zone is such as the high-pressure zone in heating mode, and the first set heating duty cycle is 50%. The specific functions and processing of the control unit 104 are further described in step S420.

[0188] The control unit 104 is further configured to, in heating mode, if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the second set inner ring temperature and less than the first set inner ring temperature, then determine the initial PWM duty cycle of the current mode as the default duty cycle, that is, control the opening degree of the throttling device to maintain the default opening degree, and control the air conditioner to maintain the current operation (i.e., maintain the default mode operation). The specific functions and processing of this control unit 104 are further described in step S430.

[0189] The control unit 104 is further configured to, in heating mode, if it is determined that the indoor ambient temperature of the air conditioner is lower than the second set inner ring temperature, determine that the operating environment of the throttling device belongs to the second set heating pressure zone, and determine the initial PWM duty cycle of the current mode as the second set heating duty cycle; wherein, the pressure of the second set heating pressure zone is lower than the pressure of the first set heating pressure zone, and the second set heating duty cycle is lower than the first set heating duty cycle. The second set heating pressure zone is like the low-pressure zone in heating mode, and the second set heating duty cycle is 20%. The specific functions and processing of this control unit 104 are further described in step S440.

[0190] Figure 9 This is a schematic diagram of the control flow of an air conditioner noise reduction control method in heating mode. Figure 9 As shown, the control flow of the air conditioner noise reduction control method in heating mode includes:

[0191] Step 31: Turn on the air conditioner in heating mode, then proceed to step 32.

[0192] Step 32: Detect the air conditioner load, such as the indoor ambient temperature T (inner loop), to determine whether the expansion valve operating environment is in a high-pressure or low-pressure zone. If the expansion valve operating environment is determined to be in a high-pressure zone, proceed to step 33; if the expansion valve operating environment is determined to be in a low-pressure zone, proceed to step 34. Determining whether the expansion valve system is in a high-pressure or low-pressure zone is based on the condenser-side load. During heating, the indoor ambient temperature T (inner loop) is used as the basis. Because the expansion valve acts as a throttling device, it is downstream of the condenser side in the refrigerant circulation; therefore, the division is based on the condenser-side load.

[0193] In step 32, it is specifically determined whether the indoor ambient temperature T_inner ring is greater than or equal to 20℃ or less than 10℃: if the indoor ambient temperature T_inner ring is greater than or equal to 20℃, proceed to step 33; if the indoor ambient temperature T_inner ring is less than 10℃, proceed to step 34. Of course, if 10℃ ≤ indoor ambient temperature T_inner ring < 20℃, the current control is maintained.

[0194] Step 33: When the indoor ambient temperature T inner ring is greater than or equal to 20℃, it is determined that the expansion valve is operating in a high-pressure zone. The duty cycle is increased, and then step 35 is executed.

[0195] In step 33, when the air conditioner load is high (T inner ring ≥ 20℃) and the expansion valve system is in the high-pressure area, more refrigerant flow needs to be compensated to meet the system operation. Therefore, it is necessary to modify the PWM and increase the duty cycle to meet this requirement. That is, in the first 15 minutes before the heating mode is turned on, when the air conditioner load is high, the initial duty cycle N0 is set to 50%. Similar to the cooling mode, this is relative to the low-pressure area. Relative to the low-pressure area, it means increasing the duty cycle to increase the refrigerant flow. Since the PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to the pressure fluctuations caused by the increase in opening degree and immediately suppress the whistling sound caused by pressure oscillation.

[0196] Step 34: When the indoor ambient temperature T inner ring is less than 10℃, it is determined that the expansion valve is operating in a low-pressure zone. The duty cycle is reduced, and then step 35 is executed.

[0197] In step 34, when the air conditioner load is low (T inner ring < 10℃) and the expansion valve system is in the low-pressure area, it is necessary to quickly reduce the refrigerant circulation volume and increase the exhaust temperature to meet the room's heating requirements. If the PID control opening adjustment scheme in the relevant solution is used, the expansion valve opening response speed is slow, the outlet air temperature is low, and the comfort is poor. At the same time, the refrigerant flow noise (the sound of water droplets caused by the intermittent impact of refrigerant on the internal structure of the expansion valve) is transmitted to the room, causing discomfort. Therefore, pulse width modulation (PWM) refrigerant flow control is adopted. By correcting the PWM and reducing the duty cycle, in the first 15 minutes of the heating mode, when the air conditioner load is low, the initial duty cycle N0 is set to 20%. Similar to the cooling mode, this is relative to the high-pressure area. Relative to the high-pressure area, it means reducing the duty cycle and reducing the refrigerant volume to achieve a fast response and solve the problem of abnormal refrigerant flow noise in the air conditioner under low load conditions.

[0198] The heating mode determines the air conditioner load based on the indoor ambient temperature. Determining whether the expansion valve system is in a high-pressure or low-pressure zone is based on the condenser-side load. During heating, the indoor ambient temperature is used as the basis; because the expansion valve acts as a throttling device and is downstream of the condenser side in the refrigerant circulation, the condenser-side load is used for classification. During cooling, the outer side is the condenser side, so the outdoor ambient temperature is used as the basis; during heating, the inner side is the condenser side, so the indoor ambient temperature is used as the basis. Essentially, it's based on the condenser-side load. High and low pressure zones are defined by load; a high condenser-side load defines a high-pressure zone, and a low condenser-side load defines a low-pressure zone. Because the expansion valve acts as a throttling device and is downstream of the condenser side in the refrigerant circulation, the condenser-side load is used for classification. This ensures a true reflection of the refrigerant pressure entering the expansion valve.

[0199] In the solution of this invention, an intelligent expansion valve system based on pulse width modulation (PWM) is adopted. The output signal is controlled by adjusting the width of the pulse signal (i.e., the duty cycle), thereby controlling the refrigerant flow of the expansion valve. This solves the problem of inaccurate flow control of the expansion valve in related solutions, achieves fast and accurate flow control, and achieves the effect of low power consumption and high efficiency.

[0200] In some implementations, when the current mode is heating mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the heating mode.

[0201] The control unit 104, based on the evaporator outlet superheat in the current mode, corrects the initial PWM duty cycle in the current mode to obtain the corrected PWM duty cycle in the current mode. The process also includes correcting the initial PWM duty cycle in the heating mode, as detailed below:

[0202] The control unit 104 is further configured to determine, in heating mode, whether the evaporator outlet superheat is greater than the target superheat in the current mode; wherein, in heating mode, the target superheat is the target value in the current mode. The specific functions and processing of the control unit 104 are further described in step S510.

[0203] The control unit 104 is further configured to, in heating mode, if it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, increase the initial PWM duty cycle in the current mode according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode; in heating mode, the set duty cycle increase method in the current mode is to correct the PWM duty cycle in real time by increasing it by 1% duty cycle / ms. The specific functions and processing of this control unit 104 are further described in step S520.

[0204] The control unit 104 is further configured to, in heating mode, if it is determined that the evaporator outlet superheat in the current mode is equal to the target superheat in the current mode, maintain the initial PWM duty cycle in the current mode, that is, use the initial PWM duty cycle in the current mode as the corrected PWM duty cycle in the current mode. The specific functions and processing of this control unit 104 are further described in step S530.

[0205] The control unit 104 is further configured to, in heating mode, if it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, increase the initial PWM duty cycle in the current mode according to the set duty cycle reduction method in the current mode to obtain the corrected PWM duty cycle in the current mode; in heating mode, the set duty cycle reduction method in the current mode is used to correct the PWM duty cycle in real time, such as by reducing the duty cycle by 1% / ms. The specific functions and processing of this control unit 104 are further described in step S540.

[0206] like Figure 9 As shown, the control flow of the air conditioner noise reduction control method in heating mode also includes:

[0207] Step 35: While executing step 33 or step 34, obtain the superheat of the evaporator outlet in the air conditioner and determine whether the superheat of the evaporator outlet is higher than the target value: if it is determined that the superheat of the evaporator outlet is higher than the target value, execute step 36 to increase the duty cycle; if it is determined that the superheat of the evaporator outlet is lower than the target value, execute step 37 to decrease the duty cycle; of course, if it is determined that the superheat of the evaporator outlet is equal to the target value, maintain the current control.

[0208] In step 35, during the pulse width modulation process, the PWM duty cycle is adjusted in real time according to the evaporator outlet superheat using a dynamic flow compensation algorithm. That is, after the air conditioner has been running for 15 minutes, the evaporator outlet superheat is acquired, and it is determined whether the evaporator outlet superheat is higher than the target value. If it is determined that the evaporator outlet superheat is higher than the target value, step 36 is executed to increase the duty cycle; if it is determined that the evaporator outlet superheat is lower than the target value, step 37 is executed to decrease the duty cycle.

[0209] Step 36: When the superheat at the evaporator outlet is higher than the target value, the PWM duty cycle is adjusted in real time by increasing the duty cycle by 1% / ms. By increasing the duty cycle, the refrigerant circulation is increased to reduce the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thus achieving coordinated control of refrigerant circulation and system pressure.

[0210] Step 37: When the superheat at the evaporator outlet is lower than the target value, the PWM duty cycle is adjusted in real time by reducing the duty cycle by 1% / ms. By reducing the duty cycle, the amount of refrigerant circulating is reduced to increase the superheat at the evaporator outlet, ensuring that the superheat is maintained between 1℃ and 3℃, thereby achieving coordinated control of the refrigerant circulation and system pressure.

[0211] Since PWM mode allows the valve core to switch rapidly between fully open and fully closed, it can quickly respond to system pressure fluctuations during the increase or decrease of the duty cycle. Therefore, it can solve the problem of whistling noise such as fluid vibration caused by continuous adjustment of the expansion valve in related solutions.

[0212] In heating mode, there are corresponding relationships between the compressor's suction temperature, system pressure, saturation temperature, and superheat under different outdoor and indoor ambient temperatures. These relationships can be referenced. Figure 11 The example shown. Figure 11 Table 2 shows the relationship between temperature and pressure in air conditioner cooling mode. The outdoor ambient temperature, indoor ambient temperature, and compressor suction temperature are detected by the air conditioner's temperature sensor. The system pressure is detected by a pressure sensor. The saturation temperature is calculated by coupling the system pressure and suction temperature (this can be done using pressure and temperature lookup software). The evaporator outlet superheat is calculated as suction temperature minus the corresponding saturation temperature. System pressure refers to suction pressure or evaporation pressure.

[0213] The table showing the relationship between temperature and pressure in heating mode is as follows: Figure 11 Table 1 is shown below. For example: Figure 11 As shown in one example, in heating mode, the inner ring temperature (i.e., the indoor ambient temperature) is 20°C, the compressor suction temperature is -5°C, the compressor suction pressure is 0.55MPa, the saturation temperature corresponding to the compressor suction pressure is -6.66°C, and the evaporator outlet superheat is 1.669°C.

[0214] In the present invention, the refrigerant flow control method of the intelligent expansion valve system based on pulse width modulation (PWM) is as follows: the continuous opening adjustment of the electronic expansion valve in related solutions is replaced with high-frequency switching control. By adjusting the duty cycle, the average flow rate is controlled, avoiding the valve core of the expansion valve from remaining in the opening range that is prone to whistling and refrigerant flow noise, and directly skipping the resonance point to avoid vibration and whistling. The refrigerant flow control using pulse width modulation (PWM) is achieved through high-frequency switching, resulting in low power consumption and high efficiency.

[0215] In the solution of this invention, a dynamic flow compensation algorithm is used to quickly respond to pressure fluctuations and instantly suppress pressure oscillations, thus solving the whistling sound problem caused by expansion valve control in related solutions and achieving the effect of suppressing pressure oscillations. By suppressing pressure oscillations, the resonance point is skipped to avoid generating vibration whistling sound.

[0216] In this invention, the opening of the expansion valve is controlled using PWM mode. Pulse Width Modulation (PWM) controls refrigerant flow through high-frequency switching, resulting in low power consumption and high efficiency. By adjusting the duty cycle, precise control of the expansion valve flow can be achieved. In related solutions, the expansion valve opening is gradually adjusted by a stepper motor, while the PWM mode allows the valve core to switch rapidly between fully open and fully closed (e.g., 100 times / second). The average refrigerant flow is controlled by adjusting the proportion of fully open time (duty cycle), providing a rapid response to pressure fluctuations. The switching cycle of PWM (e.g., 10ms) is much faster than the PID regulation (over 200ms) in related solutions, instantly suppressing pressure oscillations. Pulse Width Modulation (PWM) refrigerant flow control replaces continuous regulation with high-frequency switching, offering advantages such as fast response, low cost, and ease of implementation, representing an innovative breakthrough in solving the expansion valve whistling problem. This invention provides a PWM regulation control flowchart. Conventional PID regulation adjusts the opening based on the target exhaust volume; if the exhaust volume is higher than the target, the opening is increased; if it is lower, the opening is decreased, until it falls within the exhaust tolerance range required by the program.

[0217] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0218] According to an embodiment of the present invention, an air conditioner corresponding to a control device for an air conditioner is also provided. This air conditioner may include the control device for an air conditioner described above.

[0219] Since the processing and functions implemented by the air conditioner in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned devices, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0220] According to an embodiment of the present invention, a computer program product corresponding to the control method for an air conditioner is also provided, comprising a computer program that, when executed by a processor, implements the steps of the control method for an air conditioner described above.

[0221] Since the processing and functions implemented by the product in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0222] According to an embodiment of the present invention, a storage medium corresponding to a control method for an air conditioner is also provided, the storage medium including a stored program, wherein, when the program is executed, the device where the storage medium is located executes the steps of the control method for the air conditioner described above.

[0223] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0224] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0225] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for an air conditioner, characterized in that, The air conditioner has a throttling device, and the opening degree of the throttling device can be controlled according to a preset PWM mode; The control method for the air conditioner includes: When the air conditioner is turned on and running in the current mode, obtain the condenser-side load of the air conditioner in the current mode; Based on the condenser-side load of the air conditioner in the current mode, determine the initial PWM duty cycle for the current mode, including: In cooling mode, it is determined whether the outdoor ambient temperature of the air conditioner is greater than or equal to a first set outer ring temperature, and whether the outdoor ambient temperature of the air conditioner is less than a second set outer ring temperature; wherein, the first set outer ring temperature is greater than the second set outer ring temperature; if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the first set outer ring temperature, then it is determined that the operating environment of the throttling device belongs to the first set cooling pressure zone, and the initial PWM duty cycle of the current mode is determined to be the first set cooling duty cycle; if it is determined that the outdoor ambient temperature of the air conditioner is less than the second set outer ring temperature, then it is determined that the operating environment of the throttling device belongs to the second set cooling pressure zone, and the initial PWM duty cycle of the current mode is determined to be the second set cooling duty cycle. In heating mode, it is determined whether the indoor ambient temperature of the air conditioner is greater than or equal to a first set inner ring temperature, and whether the indoor ambient temperature of the air conditioner is less than a second set inner ring temperature; wherein, the first set inner ring temperature is greater than the second set inner ring temperature; if it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the first set inner ring temperature, then it is determined that the operating environment of the throttling device belongs to the first set heating pressure zone, and the initial PWM duty cycle of the current mode is determined to be the first set heating duty cycle; if it is determined that the indoor ambient temperature of the air conditioner is less than the second set inner ring temperature, then it is determined that the operating environment of the throttling device belongs to the second set heating pressure zone, and the initial PWM duty cycle of the current mode is determined to be the second set heating duty cycle; The opening degree of the throttling device is controlled according to the initial PWM duty cycle in the current mode; After a first set time, the evaporator outlet superheat of the air conditioner in the current mode is obtained; Based on the evaporator outlet superheat in the current mode, the initial PWM duty cycle in the current mode is corrected to obtain the corrected PWM duty cycle in the current mode. Adjust the opening degree of the throttling device according to the modified PWM duty cycle in the current mode.

2. The control method for an air conditioner according to claim 1, characterized in that, Current modes include: cooling mode and heating mode; Obtaining the condenser-side load of the air conditioner in the current mode includes: When the current mode is cooling mode, the outdoor ambient temperature of the air conditioner is obtained as the condensing-side load of the air conditioner in cooling mode; When the current mode is heating mode, the indoor ambient temperature of the air conditioner is obtained as the condensing load of the air conditioner in heating mode.

3. The control method for an air conditioner according to claim 1, characterized in that, When the current mode is cooling mode, the condenser-side load of the air conditioner in the current mode is the outdoor ambient temperature of the air conditioner; Based on the condenser-side load of the air conditioner in the current mode, the initial PWM duty cycle in the current mode is determined, which further includes: if it is determined that the outdoor ambient temperature of the air conditioner is greater than or equal to the second set outer ring temperature and less than the first set outer ring temperature, then the initial PWM duty cycle in the current mode is determined to be the default duty cycle. The pressure in the second set cooling pressure zone is lower than the pressure in the first set cooling pressure zone, and the duty cycle of the second set cooling zone is lower than the duty cycle of the first set cooling zone.

4. The control method for an air conditioner according to claim 1 or 3, characterized in that, When the current mode is cooling mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the cooling mode. Based on the evaporator outlet superheat in the current mode, the initial PWM duty cycle in the current mode is corrected to obtain the corrected PWM duty cycle in the current mode, including: In cooling mode, determine whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; If it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode. If the evaporator outlet superheat in the current mode is determined to be equal to the target superheat in the current mode, then the initial PWM duty cycle in the current mode is maintained. If it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the duty cycle reduction method set in the current mode, so as to obtain the corrected PWM duty cycle in the current mode.

5. The control method for an air conditioner according to claim 1, characterized in that, When the current mode is heating mode, the condensing load of the air conditioner in the current mode is the indoor ambient temperature of the air conditioner; Based on the condenser-side load of the air conditioner in the current mode, the initial PWM duty cycle in the current mode is determined, and the method further includes: If it is determined that the indoor ambient temperature of the air conditioner is greater than or equal to the second set inner ring temperature and less than the first set inner ring temperature, then the initial PWM duty cycle in the current mode is determined to be the default duty cycle. The pressure in the second set heating pressure zone is lower than the pressure in the first set heating pressure zone, and the duty cycle of the second set heating is lower than the duty cycle of the first set heating.

6. The control method for an air conditioner according to claim 1 or 5, characterized in that, When the current mode is heating mode, the evaporator outlet superheat in the current mode is the same as the evaporator outlet superheat in the heating mode. Based on the evaporator outlet superheat in the current mode, the initial PWM duty cycle in the current mode is corrected to obtain the corrected PWM duty cycle in the current mode, which also includes: In heating mode, determine whether the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode; If it is determined that the evaporator outlet superheat in the current mode is greater than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the set duty cycle increase method in the current mode to obtain the corrected PWM duty cycle in the current mode. If the evaporator outlet superheat in the current mode is determined to be equal to the target superheat in the current mode, then the initial PWM duty cycle in the current mode is maintained. If it is determined that the evaporator outlet superheat in the current mode is less than the target superheat in the current mode, then the initial PWM duty cycle in the current mode is increased according to the duty cycle reduction method set in the current mode, so as to obtain the corrected PWM duty cycle in the current mode.

7. A control device for an air conditioner, wherein the control method for an air conditioner as described in any one of claims 1 to 6 is used for control, characterized in that, The air conditioner has a throttling device, and the opening degree of the throttling device can be controlled according to a preset PWM mode; The control device for the air conditioner includes: The acquisition unit is configured to acquire the condenser-side load of the air conditioner in the current mode when the air conditioner is turned on and running in the current mode; The control unit is configured to determine the initial PWM duty cycle of the current mode based on the condenser-side load of the air conditioner in the current mode; The control unit is also configured to control the opening degree of the throttling device according to the initial PWM duty cycle in the current mode; The acquisition unit is also configured to acquire the evaporator outlet superheat in the current mode of the air conditioner after a first set time. The control unit is also configured to correct the initial PWM duty cycle of the current mode based on the evaporator outlet superheat in the current mode, so as to obtain the corrected PWM duty cycle of the current mode. The control unit is also configured to adjust the opening of the throttling device according to the modified PWM duty cycle in the current mode.

8. An air conditioner, characterized in that, include: The control device for an air conditioner as described in claim 7.

9. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the air conditioner according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method for the air conditioner according to any one of claims 1 to 6.

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