A method for controlling the expansion valve to enable rapid cooling and heating in variable frequency air conditioners.

Abstract

This invention specifically relates to a method for controlling the expansion valve of a variable frequency air conditioner to achieve rapid cooling and heating. The method involves controlling the expansion valve opening PLUS according to formula (1) within the first 5 minutes of compressor operation: PLUS = F × Nrps + G (1), where Nrps is the actual compressor speed, F is the variation coefficient, G is a variable constant, and the sampling time is 10 seconds. After the compressor has been running for 5 minutes, the calculated upper and lower limits of the target compressor discharge superheat SPH and SPL are used in a fuzzy control with the actual compressor discharge superheat TdSH to change the expansion valve opening. By optimizing and adjusting the initial expansion valve opening of the variable frequency air conditioner and integrating it with the compressor frequency, the air conditioner can achieve a basically stable capacity within 5 minutes, thereby improving the cooling (heating) speed and providing users with a better user experience.

Description

TECHNICAL FIELD

[0001] The present application relates to the air conditioning technical field, specifically to an expansion valve control method for making the variable frequency air conditioner cool and heat quickly. BACKGROUND

[0002] At present, the air conditioner installed in the market can achieve certain refrigeration or heating effect within 10-30 minutes, many users complain that the refrigeration (heating) speed is slow, and the phenomenon of poor user experience occurs. At present, most users in the market choose variable frequency air conditioner, the variable frequency air conditioner generally selects small capacity, and the room insulation is poor, the variable frequency air conditioner needs certain adjustment time due to frequency, expansion valve opening, air speed change and other factors, so the air conditioner refrigeration (heating) speed becomes relatively slow, and even more than 30 minutes is needed to feel the effect, therefore, it is particularly important to improve the air conditioner refrigeration (heating) effect.

[0003] At present, most manufacturers improve the effect by increasing the use frequency of the air conditioner and the air volume of the air conditioner indoor unit. This method will first make the air conditioner noise larger and the user experience worse, and at the same time, it will increase the power consumption of the air conditioner, so as to increase the power consumption of the user. Through test demonstration and comparative analysis, under the condition that the upper limit of the air conditioner compressor frequency and the indoor unit air speed are unchanged, according to different outdoor ambient temperature, the expansion valve opening and the compressor frequency can be accurately and quickly adjusted to realize the high integration of the expansion valve opening and the compressor frequency, ensure the safe operation of the machine, and make the machine run smoothly at the fastest speed, so as to realize the optimization of the refrigeration (heating) effect. SUMMARY

[0004] The purpose of the present application is to provide an expansion valve control method for making the variable frequency air conditioner cool and heat quickly, so as to solve the problem of slow refrigeration and heating speed of the existing variable frequency air conditioner.

[0005] In order to achieve the above purpose, the present application provides the following technical scheme: an expansion valve control method for making the variable frequency air conditioner cool and heat quickly: the opening of the expansion valve PLUS is controlled according to formula (1) within 5 minutes after the compressor starts running:

[0006] PLUS=F x Nrps+G (1)

[0007] Wherein, Nrps is the actual number of revolutions of the compressor, F is the change coefficient, G is the variable constant, and the sampling time is 10 seconds;

[0008] After 5 minutes of the compressor starting to run, the calculated target compressor discharge superheat upper limit SPH and lower limit SPL and the actual compressor discharge superheat TdSH are subjected to fuzzy control, so as to change the opening of the expansion valve.

[0009] Preferably, when the outdoor environment temperature varies between 22-45℃, F has four values, the specific values F1 is 0.6-0.8, F2 is 2.0-2.5, F3 is 2.5-2.7, and F4 is 2.7-3.0; when the outdoor environment temperature varies between 43-45℃, G has two values, G1 is 10-20, and G2 is 30-40;

[0010] When the outdoor environment temperature varies between -8-16℃, F has four values, the specific values F1 is 0.6-0.8, F2 is 0.8-0.9, F3 is 0.9-1.0, and F4 is 4.0-5.0; when the outdoor environment temperature varies between 2-16℃, G has three values, G1 is 10-20, G2 is 50-60, and G3 is 40-50.

[0011] Compared with the prior art, the present application has the following advantages:

[0012] We optimize the initial expansion valve opening degree of the variable frequency air conditioner, and highly integrate it with the compressor frequency, so that the air conditioner can reach the basic stable capacity within 5 minutes, thereby improving the refrigeration (heating) speed and providing better body feeling for the user. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Fig. 1 is a refrigerant circulation system diagram of the variable frequency air conditioner;

[0014] Figure 2 Fig. 4 is a refrigeration F value diagram;

[0015] Figure 3 Fig. 5 is a refrigeration G value diagram;

[0016] Figure 4 Fig. 6 is a heating F value diagram;

[0017] Figure 5 Fig. 7 is a heating G value diagram;

[0018] Figure 6 Fig. 8 is a refrigeration target compressor exhaust gas superheat upper limit SPH and lower limit SPL calculation diagram;

[0019] Figure 7 Fig. 9 is another refrigeration target compressor exhaust gas superheat upper limit SPH and lower limit SPL calculation diagram;

[0020] Figure 8 Fig. 10 is a heating target compressor exhaust gas superheat upper limit SPH and lower limit SPL calculation diagram.

[0021] Fig. 10 is a heating target compressor exhaust gas superheat upper limit SPH and lower limit SPL calculation diagram.

[0022] 1, indoor heat exchanger, 2, outdoor heat exchanger, 3, compressor, 4, four-way valve, 5, expansion valve, 6, outdoor heat exchange temperature sensor, 7, outdoor ambient temperature sensor, 8, indoor ambient temperature sensor, 9, indoor heat exchange sensor, 10, exhaust temperature sensor. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0024] The present embodiment provides an expansion valve control method for making a variable frequency air conditioner cool and heat quickly, Figure 1 A refrigerant circulation system diagram of a variable frequency air conditioner is shown, which includes an indoor heat exchanger 1, an outdoor heat exchanger 2, a compressor 3, a four-way valve 4, an expansion valve 5, an outdoor heat exchange temperature sensor 6, an outdoor ambient temperature sensor 7, an indoor ambient temperature sensor 8, an indoor heat exchange sensor 9, an exhaust temperature sensor 10, and the like. The control method of the present embodiment is a control method for the expansion valve 5. Within 5 minutes of starting operation of the compressor 3, the opening degree PLUS of the expansion valve 5 is controlled according to formula (1):

[0025] PLUS=F×Nrps+G (1)

[0026] Wherein, Nrps is the actual number of revolutions of the compressor, F is the change coefficient, G is the variable constant, and the sampling time is 10 seconds.

[0027] The values of F and G are different in different working conditions of refrigeration and heating, such as Figure 2 As shown, when the outdoor ambient temperature changes between 22-45℃, the value of F has four kinds, and the specific values F1 is 0.6-0.8, F2 is 2.0-2.5, F3 is 2.5-2.7, and F4 is 2.7-3.0. As shown in Figure 3 When the outdoor ambient temperature is between 43-45℃, the value of G has two kinds, G1 is 10-20, and G2 is 30-40.

[0028] As shown in Figure 4 When the outdoor ambient temperature changes between -8-16℃, the value of F has four kinds, and the specific values F1 is 0.6-0.8, F2 is 0.8-0.9, F3 is 0.9-1.0, and F4 is 4.0-5.0. As shown in Figure 5As shown, when the outdoor ambient temperature varies from 2 to 16°C, G has three values, G1 is 10-20, G2 is 50-60, and G3 is 40-50.

[0029] Formula (1) is calculated according to the experimental actual expansion valve opening data combined with the outdoor ambient temperature in different intervals and different compressor operating frequencies. First, the maximum machine performance capacity expansion valve opening under each different outdoor ambient temperature and corresponding different compressor operating frequency is found. Under the condition of ensuring the safety of system operation: according to the valve opening list of each different outdoor ambient temperature from the lowest frequency to the highest frequency, the regular relationship between the expansion valve opening and the frequency is found, and the change coefficient F value and G value under each ambient temperature changing with the frequency are determined through linear calculation, because the outdoor ambient temperature is close to the required exhaust superheat, and the required expansion valve opening is also basically similar. Then, the outdoor ambient temperature interval with approximately the same expansion valve opening is found through the expansion valve opening under the condition of different outdoor ambient temperatures at the same frequency, thereby analyzing and dividing the different change coefficient F value and G value of each outdoor ambient temperature control section. Finally, this control logic is written into the air conditioner control substrate for system actual operation control. Because the compressor frequency changes constantly when the air conditioner starts to run, within 5 minutes of starting, the expansion valve opening is timely corrected according to formula (1) with the change of the compressor frequency, and the expansion valve opening is adjusted to the target exhaust superheat required for the nearly stable operation of the air conditioner, so that the running capacity of the air conditioner quickly approaches stability, reduces the adjustment range and the time of fluctuation, and after 5 minutes, only the expansion valve opening is fine-tuned for further correction according to the target superheat, thereby ensuring the effective capacity of the compressor frequency change process to be accelerated.

[0030] After the compressor starts to run for 5 minutes, the upper limit SPH(TdSH) and the lower limit SPL(TdSH) of the target compressor exhaust superheat calculated according to formulas (2)-(7) and the actual compressor exhaust superheat TdSH are subjected to fuzzy control to change the expansion valve opening.

[0031] The compressor exhaust superheat TdSH is defined as follows:

[0032] When refrigerating: TdSH = exhaust pipe temperature Tho-D - outdoor heat exchange temperature Tho-R,

[0033] When heating: TdSH = exhaust pipe temperature Tho-D - indoor heat exchange temperature Thi-R.

[0034] Referring to Figure 6 , refrigerating, and 25°C ≤ Tho-A < 46°C, SPH = d*N + e (2)

[0035] SPL = a*N + b (3)

[0036] Referring toFigure 7 , refrigeration, and Tho-A < 25°C, 46°C < Tho-A, SPH = g*N + h (4)

[0037] SPL = f*N + c (5)

[0038] Referring to Figure 8 , heating, SPH = t*N + y (6)

[0039] SPH = x*N + z (7)

[0040] The a, b, c, d, e, f, g, h, t, x, y, z are coefficients, and N is the actual number of revolutions of the compressor.

[0041] According to Figure 6 , 7 , 8 determines the target compressor discharge superheat TdSH, the deviation E(n), and the sampling time.

[0042] The target compressor discharge superheat TdSH in the a region of the figure is SPH, the deviation E(n) is equal to TdSH-SPH, and the next sampling time is 10 seconds;

[0043] The deviation E(n) in the i region of the figure is equal to 0, and the next sampling time is 120 seconds;

[0044] The target compressor discharge superheat TdSH in the u region of the figure is SPL, the deviation E(n) is equal to TdSH-SPL, and the next sampling time is 10 seconds.

[0045] The time change differential DE of the deviation E(n) is DE = E(n)-E(n-1) (°C / sampling time), and the value determined from the deviation E(n) and the time change differential DE is added (or subtracted) to the expansion valve opening degree, so that the expansion valve opening degree changes according to Table 1.

[0046] Table 1 Fuzzy control rule of the expansion valve opening degree after the compressor has been running for 5 minutes

[0047]

[0048] By the method of the embodiment, the expansion valve opening degree can be adjusted to the optimal opening degree in real time under the condition that the compressor frequency is constantly changing at the start of operation, that is, the expansion valve opening degree is adjusted to reach the target discharge superheat of the air conditioner when the air conditioner is running almost steadily, so that the running capacity of the air conditioner quickly approaches steady, the large adjustment range and the long fluctuation time are reduced, and only the fine adjustment of the expansion valve opening degree is required according to the target superheat after 5 minutes, so that the air conditioner can exert the best capacity within 5 minutes, the buffer period is reduced, and the refrigeration (heating) speed is maximized under the condition that the noise and the use cost remain unchanged.

[0049] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the application. The scope of the application is not to be limited by the embodiments shown and described, but only by the claims and their equivalents.

Claims

1. An expansion valve control method for making a variable refrigerant air conditioner cool and heat quickly, characterized in that, The method is that the opening of the expansion valve is controlled according to formula (1) within 5 minutes after the compressor starts running: PLUS=FxNrps+G (1) Wherein, Nrps is the actual number of revolutions of the compressor, F is a variable coefficient, G is a variable constant, the sampling time is 10 seconds; after 5 minutes of the start of the compressor, the calculated target upper limit SPH and lower limit SPL of the compressor discharge superheat degree and the actual compressor discharge superheat degree TdSH are subjected to fuzzy control to change the opening of the expansion valve; When the outdoor ambient temperature changes between 22-45℃, the value of F has four kinds, the specific value F1 is 0.6-0.8, F2 is 2.0-2.5, F3 is 2.5-2.7, F4 is 2.7-3.0; when the outdoor ambient temperature is between 43-45℃, the value of G has two kinds, G1 is 10-20, G2 is 30-40; when the outdoor ambient temperature changes between -8-16℃, the value of F has four kinds, the specific value F1 is 0.6-0.8, F2 is 0.8-0.9, F3 is 0.9-1.0, F4 is 4.0-5.0; when the outdoor ambient temperature changes between 2-16℃, the value of G has three kinds, G1 is 10-20, G2 is 50-60, G3 is 40-50.

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