Method and system for judging and identifying blockage of system circuit of heating mode of variable frequency air conditioner

Abstract

The present application relates to the field of air conditioner circuit blockage identification, in order to improve the accuracy of the blockage judgment in heating mode, a variable frequency air conditioner heating mode system circuit blockage judgment and identification method and system are provided, the first level of blockage judgment is carried out according to the power of the outdoor unit, the second level of blockage judgment is carried out according to the change amount of the indoor coil temperature; the third level of blockage judgment is carried out again according to the change amount of the indoor coil temperature after fixing the frequency and reducing the speed of the indoor fan; the fourth level of blockage judgment is carried out again according to the change amount of the indoor coil temperature; multi-dimensional and multi-level judgment is adopted, and the change amount of the indoor coil temperature and the downshift fixed frequency measure are increased, the heating blockage judgment precision is improved, and the misjudgment probability is reduced; at the same time, the blockage fault is judged and distinguished according to the risk level, the high-risk fault is locked to avoid explosion accident, and the safety is higher.

Description

Technical Field

[0001] This invention relates to the field of air conditioning circuit blockage identification, specifically a method and system for judging and identifying circuit blockage in a variable frequency air conditioning heating mode system. Background Technology

[0002] Current methods for determining circuit blockage in air conditioning systems primarily rely on the temperature difference between the outdoor ambient temperature, compressor exhaust temperature, and indoor coil temperature (CN202111371353.9); or they utilize the rate of change of temperature difference between the outdoor ambient temperature, electronic expansion valve opening, compressor frequency, and compressor winding temperature to determine circuit blockage (CN202011460250.5). Alternatively, when the air conditioning system is in heating mode, the system is checked for blockage; if blockage is detected, the system is switched from heating to cooling mode; the operating parameters of the air conditioning system in cooling mode are obtained; and based on whether the operating parameters in cooling mode are normal, the type of blockage is determined, including ice blockage and non-ice blockage (CN202210410855.6).

[0003] In heating scenarios, outdoor ambient temperature sensors and outdoor unit coil sensors mentioned above are easily covered by ice and snow or frozen, leading to inaccurate temperature detection and thus misjudgment or inaccurate assessment. The method of judging and identifying by switching modes is cumbersome, and switching from heating mode to cooling mode may cause discomfort or misunderstanding for some users. Summary of the Invention

[0004] To improve the accuracy of blockage detection in heating mode, this application provides a method and system for detecting and identifying blockages in the circuit of a variable frequency air conditioner in heating mode.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] Methods for identifying and determining system circuit blockage in variable frequency air conditioner heating mode, including:

[0007] S100: The air conditioner is turned on and runs in heating mode. When the compressor starts running for time a, record the maximum value of the outdoor unit power Power_max and the indoor coil temperature Tic_a within time a, and proceed to the next step S110; a is the time taken for the outdoor unit power to reach the maximum value when the system is completely blocked or the valve is not open.

[0008] S110: The compressor continues to run until time b, obtains the current power Power_b, if Power_b / Power_max < △T1, then proceed to step S120, otherwise maintain normal operation;

[0009] S120: Continue to run until time c, and judge the temperature rise change between the indoor coil temperature Tic_c at the current moment and the indoor coil temperature Tic_a at time a. If Tic_c - Tic_a < T1, then enter step S130; if not satisfied, maintain normal operation.

[0010] S130: After continuing to run until time d, preset the current frequency to F1, synchronously drive the internal fan speed to decrease by one gear at the set gear, and then enter step S140;

[0011] S140: After continuing to run until time e, continuously record the power at subsequent times f, g, and h, as well as the compressor motor winding temperature value TCR_h and the exhaust temperature TP_h at time point h;

[0012] Judge whether both of the following are satisfied simultaneously:

[0013] Power_f > Power_e * K1 and Power_g > Power_f * K1 and Power_h > Power_g * K1;

[0014] TCR_h - TP_h > T2;

[0015] If both conditions are satisfied simultaneously, it is determined that the first system loop is blocked; if any one of the conditions is not satisfied, enter step S150;

[0016] S150: Continue to run until time i, and judge whether the difference between the current internal disk temperature Tic_i and the internal disk temperature Tic_e at time e is less than T1. If so, it is determined that the second system loop is blocked; if not, normal operation.

[0017] Furthermore, the compressor motor winding temperature value TCR_h uses the estimated value of the compressor motor winding temperature.

[0018] Furthermore, the method for obtaining the estimated value of the compressor motor winding temperature is: calculate the basic temperature according to the change relationship between the magnetic flux and the temperature, calculate the correction temperature according to the relationship between the temperature and the current, and obtain the estimated value of the compressor motor winding temperature by correcting the basic temperature with the correction temperature.

[0019] Furthermore, the method for obtaining the estimated value of the compressor motor winding temperature is: determine the magnetic flux change rate and resistance change rate corresponding to the motor, and determine the estimated value of the compressor motor winding temperature based on the magnetic flux change rate and resistance change rate of the motor.

[0020] Furthermore, the value range of a is 30s to 50s, the value range of b is 70s to 90s, the value range of c is 120s to 150s, the value range of d is 160s to 180s, the value range of e is 190s to 200s, the value range of f is 210s to 230s, the value range of g is 240s to 260s, the value range of h is 270s to 290s, and the value range of i is 300s to 320s.

[0021] Furthermore, the value of △T1 ranges from 75% to 85%, T1 is 2℃, T2 is 20℃, and K1 is 3%.

[0022] Furthermore, F1 represents the current operating frequency of the air conditioner at time d.

[0023] Furthermore, when the first system circuit is determined to be blocked, the machine is immediately stopped and the compressor is locked. After repair, the machine is unlocked and restarted. When the second system circuit is determined to be blocked, the machine is stopped for protection. The machine can be restarted after power is restored.

[0024] Furthermore, when it is determined that the first system loop is blocked or the second system loop is blocked, the method also includes: pushing the blockage information to the cloud server.

[0025] The variable frequency air conditioner heating mode system circuit blockage detection and identification system includes:

[0026] Time acquisition unit: used to collect time information;

[0027] Power acquisition unit: Used to acquire the power value of the outdoor unit;

[0028] Temperature acquisition unit: used to acquire compressor motor winding temperature, indoor coil temperature and exhaust temperature;

[0029] Control unit: Used to implement a method for identifying and determining system circuit blockage in variable frequency air conditioner heating mode based on the collected information.

[0030] The advantages of this invention compared to the prior art are:

[0031] The system employs a multi-dimensional, multi-level approach to blockage detection. First, it assesses blockage based on the outdoor unit's power output. Second, it uses changes in indoor coil temperature for temperature assessment. Third, it uses a fixed frequency and reduced indoor fan speed for temperature assessment. Finally, it assesses blockage based on changes in indoor coil temperature. This multi-dimensional approach, combined with measures to measure changes in indoor coil temperature and reduce frequency, improves the accuracy of heating blockage detection and reduces the probability of false positives. Furthermore, it differentiates blockage faults by risk level, locking the compressor in case of high-risk faults to prevent combustion or explosion accidents, thus enhancing safety. Attached Figure Description

[0032] Figure 1 Flowchart of a method for identifying and determining system circuit blockage in variable frequency air conditioner heating mode;

[0033] Figure 2 This is a data table for normal heating start-up operation;

[0034] Figure 3 This is the normal heating start-up operation curve;

[0035] Figure 4 Startup data table for heating circuit blockage;

[0036] Figure 5 Start-up and operation curve for heating circuit blockage;

[0037] Figure 6 Preset fan speed and frequency data table for normal heating;

[0038] Figure 7 Preset fan speed and frequency data table for heating blockage. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] like Figure 1 As shown, the method for identifying and determining system circuit blockage in the heating mode of a variable frequency air conditioner includes:

[0041] S100: The air conditioner is turned on and runs in heating mode. When the compressor starts running for time a, record the maximum value of the outdoor unit power Power_max and the indoor coil temperature Tic_a within time a. Here, a is the time it takes for the outdoor unit power to reach the maximum value when the system is completely blocked or the valve is not open. The value range is generally 30s to 50s. Proceed to the next step S110.

[0042] S110: The compressor continues to run until time b, where the value of b ranges from 70s to 90s. The current power Power_b is obtained. If Power_b / Power_max < △T1, where △T1 is preferably 75% to 85%, then proceed to the next step S120; otherwise, maintain normal operation.

[0043] If the system is completely blocked or the valves are not open, the outdoor unit's power will reach its maximum value at the moment the compressor starts due to its high torque. Afterward, because there is no refrigerant flow, the compressor runs under no-load, and its power will drop significantly (see appendix). Figure 5) Even if the frequency increases, its power is 10% - 50% or more lower than the peak power at startup. Based on this, the first-level blockage judgment can be carried out. Compared with traditional temperature sensors, using power for judgment has a more timely response, a smaller error range, and a more accurate judgment.

[0044] S120: Continue to run until time c. The value range of c is 120s - 150s. Judge the temperature rise change of the indoor coil temperature Tic_c at the current moment and the indoor coil temperature Tic_a at time a. If Tic_c - Tic_a < T1 (preferably 2°C), then enter the next step S130. If not satisfied, maintain normal operation.

[0045] S130: After continuing to run until time d, the value range of d is 160s - 180s. Preset the current frequency to F1 (preferably the current frequency of the air conditioner at time d), and synchronously drive the speed of the internal fan to decrease by one gear in the set gear, and enter the next step S140.

[0046] By fixing the frequency, the influence of frequent fluctuations on the detection accuracy can be avoided; the purpose of reducing the speed of the internal fan by one gear is to reduce the heat exchange of the internal unit. If the system is normal, the indoor coil temperature will rise rapidly when the air volume decreases. If the system is blocked, the indoor coil temperature will not have a temperature rise change.

[0047] S140: After continuing to run until time e, continuously record the power at subsequent times f, g, and h, as well as the compressor motor winding temperature value TCR_h and the exhaust temperature TP_h at time h; the value range of e is 190s - 200s, the value range of f is 210s - 230s, the value range of g is 240s - 260s, and the value range of h is 270s - 290s;

[0048] Judge whether both are satisfied simultaneously:

[0049] Power_f > Power_e * K1 and Power_g > Power_f * K1 and Power_h > Power_g * K1, K1 is preferably 3%;

[0050] TCR_h - TP_h > T2 (preferably 20°C);

[0051] If both conditions are satisfied simultaneously, it is determined that the first system loop is blocked. In this case, the power continuously increases. Due to the blocked system loop, the exhaust temperature is low, but the temperature of the internal motor winding of the compressor is high. According to experimental verification, this feature is system loop blockage + mixed air, with a high risk of compressor explosion. It is necessary to immediately stop the machine and lock the compressor, and synchronously push it to the cloud server, requiring after-sales to visit the site to check for leakage points and blockage points, and unlock and start the machine after repair. If any one of the conditions is not satisfied, enter step S150.

[0052] Furthermore, the compressor motor winding temperature value TCR_h is a calculated value of the compressor motor winding temperature. There are two methods for obtaining the calculated value of the compressor motor winding temperature: The first method is to calculate the basic temperature based on the relationship between magnetic flux and temperature, as disclosed in patent application number 201610808947.4, and calculate the correction temperature based on the relationship between temperature and current. The basic temperature is then corrected using the correction temperature to obtain the calculated value of the compressor motor winding temperature. The second method is to determine the calculated value of the compressor motor winding temperature based on the rate of change of magnetic flux and the rate of change of resistance of the motor, as disclosed in patent application number 201910249866.9.

[0053] In the event of a system circuit blockage, the compressor discharge temperature is low due to the lack of effective refrigerant flow and heat exchange, failing to accurately reflect the internal temperature of the compressor. Therefore, the effectiveness of traditional methods relying on discharge sensors to identify system blockages is affected. However, this invention utilizes compressor motor winding temperature estimation technology to calculate the internal motor winding temperature of the compressor in real time, which is essentially equivalent to the measured winding temperature. By combining the calculated value of the compressor motor winding temperature with the difference between the discharge temperature, the blockage judgment is made with higher accuracy.

[0054] S150: Continue running until time i, where i ranges from 300s to 320s. Determine if the difference between the current inner disk temperature Tic_i and the inner disk temperature Tic_e at time e is less than T1. If so, it is determined that the second system loop is blocked, requiring a shutdown protection. Powering on again will allow the machine to start. The data can also be simultaneously pushed to the cloud server, requesting after-sales service to investigate the blockage. If not, normal operation continues.

[0055] It should be noted that the preset values ​​of this invention can all be adjusted based on the blockage experiment. Using the judgment method of this invention, blockage judgment can be completed approximately 300 seconds before power-on, resulting in higher timeliness and thus improving the overall safety and reliability of the machine; the judgment process does not require switching cooling modes, providing a better user experience.

[0056] This application also provides a system for detecting and identifying circuit blockages in a variable frequency air conditioner heating mode system, including:

[0057] Time acquisition unit: used to collect time information;

[0058] Power acquisition unit: Used to acquire the power value of the outdoor unit;

[0059] Temperature acquisition unit: used to acquire compressor motor winding temperature, indoor coil temperature and exhaust temperature;

[0060] Control unit: Used to implement a method for identifying and determining system circuit blockage in variable frequency air conditioner heating mode based on the collected information.

[0061] Example

[0062] For ease of comparison, this embodiment also conducted a normal heating start-up operation experiment. The core parameters, such as power, for normal heating start-up operation are shown in the table below. Figure 2 The curve is shown. Figure 3 For preset wind speed and frequency data, please refer to [link / reference]. Figure 6 .

[0063] Under the heating conditions specified in GB / T7725 standard, the shut-off valve of the air conditioner should be closed before starting the unit (this can be done by closing the small shut-off valve, the large shut-off valve, or both shut-off valves). This scenario simulates the situation where the valve was not opened after the air conditioner was installed, or the air conditioner was not used for a period of time, and impurities accumulated and blocked the system circuit.

[0064] When the compressor starts running, it takes 35 seconds for the maximum power (Power_max) to reach 661W (see...). Figure 4 After that, the power dropped rapidly and significantly (see...). Figure 5 This is significantly different from normal heating start-up. The system blockage condition Power / Power_max*100%<△T1 can be triggered in 90 seconds, that is, 428 / 661*100%=64.75%, 64.75%<△T1 (△T1 is preferably 75~85%), and the blockage condition is established.

[0065] It ran for about 140 seconds (see Figure 7 The difference between the current indoor coil temperature Tic_c and the indoor coil temperature Tic_a at 35S is 28-34.8=-6.8, which satisfies Tic_c-Tic_a<T1 (T1 is preferably 2℃); continue running for 180S and fix the preset frequency at 75.9Hz, and reduce the indoor unit fan speed from high speed to medium speed. After running for 200s, the power is continuously measured at 230s, 260s and 290s. The power growth rate is less than K1 (3%), and the difference between the calculated value of the compressor motor winding temperature and the exhaust temperature at 290s is less than 20℃. Therefore, the circuit blockage + air mixing does not meet the requirements (the actual experiment only showed circuit blockage and no air mixing).

[0066] The temperature difference between the inner disk temperature at time i (300S) and the inner disk temperature at time e (200S) is negative and less than 2℃, which proves that the system circuit is blocked. The system can be shut down for protection, and the blockage information can be pushed to the cloud server to indicate that the system is blocked and on-site repair is required.

[0067] By comparison Figure 6 , Figure 7It can be seen that under normal conditions, after fixing the preset frequency and reducing the fan speed by one level, the indoor coil temperature will rise rapidly, with a temperature rise of at least 5°C. Moreover, the difference between the calculated value of the compressor motor winding temperature and the exhaust temperature is only 4.6°C, which fully proves the effectiveness and rationality of the blockage judgment logic.

Claims

1. A method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system, characterized in that, Including: S100: The air conditioner is turned on and operates in the heating mode. When the compressor starts and runs for a time a, record the maximum value Power_max of the indoor and outdoor unit power and the indoor coil temperature Tic_a at time a, and enter the next step S110; a is the time it takes for the outdoor unit power to reach the maximum value in the case of a complete blockage of the system or the valve not being opened; S110: The compressor continues to run until time b, and obtain the current power Power_b. If Power_b / Power_max < △T1, then enter step S120, otherwise maintain normal operation; S120: Continue to run until time c, and judge the temperature rise change between the indoor coil temperature Tic_c at the current moment and the indoor coil temperature Tic_a at time a. If Tic_c - Tic_a < T1, then enter step S130, if not satisfied, then maintain normal operation; S130: After continuing to run until time d, fix the operating frequency at the current operating frequency F1 of the air conditioner, synchronously drive the speed of the indoor fan to decrease one gear at the set gear, and then enter step S140; S140: After continuing to run until time e, continuously record the power at subsequent times f, g, and h, as well as the compressor motor winding temperature value TCR_h and the exhaust temperature TP_h at time h; Judge whether both are satisfied simultaneously: Power_f > Power_e * K1 and Power_g > Power_f * K1 and Power_h > Power_g * K1; TCR_h - TP_h > T2; If both conditions are satisfied simultaneously, it is determined that the first system loop is blocked. If any one of the conditions is not satisfied, enter step S150; S150: Continue to run until time i, and judge whether the difference between the current indoor coil temperature Tic_i and the indoor coil temperature Tic_e at time e is less than T1. If so, it is determined that the second system loop is blocked. If not, it operates normally; Specifically, the value range of a is 30s - 50s, the value range of b is 70s - 90s, the value range of c is 120s - 150s, the value range of d is 160s - 180s, the value range of e is 190s - 200s, the value range of f is 210s - 230s, the value range of g is 240s - 260s, the value range of h is 270s - 290s, and the value range of i is 300s - 320s; The value range of △T1 is 75% - 85%, T1 is 2℃, T2 is 20℃, and K1 is taken as 3%.

2. The method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system according to claim 1, characterized in that, The compressor motor winding temperature value TCR_h uses the estimated value of the compressor motor winding temperature.

3. The method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system according to claim 2, characterized in that, The method for obtaining the estimated value of the compressor motor winding temperature is: calculate the basic temperature according to the change relationship between the magnetic flux and the temperature, calculate the correction temperature according to the relationship between the temperature and the current, and obtain the estimated value of the compressor motor winding temperature by correcting the basic temperature with the correction temperature.

4. The method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system according to claim 2, characterized in that, The method for obtaining the estimated value of the compressor motor winding temperature is: determine the magnetic flux change rate and resistance change rate corresponding to the motor, and determine the estimated value of the compressor motor winding temperature based on the magnetic flux change rate and resistance change rate of the motor.

5. The method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system according to any one of claims 1-4, characterized in that, If the first system circuit is determined to be blocked, the machine should be stopped immediately and the compressor locked. After repair, the machine should be unlocked and restarted. If the second system circuit is determined to be blocked, the machine should be stopped for protection. The machine can be restarted after power is restored.

6. The method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system according to claim 5, characterized in that, When it is determined that the first system loop is blocked or the second system loop is blocked, the process also includes: pushing the blockage information to the cloud server.

7. A system for detecting and identifying circuit blockages in the heating mode of a variable frequency air conditioner, characterized in that: include: Time acquisition unit: used to collect time information; Power acquisition unit: Used to acquire the power value of the outdoor unit; Temperature acquisition unit: used to acquire compressor motor winding temperature, indoor coil temperature and exhaust temperature; Control unit: Used to implement the variable frequency air conditioner heating mode system circuit blockage judgment and identification method as described in any one of claims 1-6 based on the collected information.

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