Variable frequency air conditioner heating mode system loop blockage judgment and identification method and system

Abstract

The invention relates to the field of air conditioner loop blockage recognition, and provides a variable frequency air conditioner heating mode system loop blockage judgment recognition method and system in order to improve the accuracy of blockage judgment in a heating mode, first-level blockage judgment is carried out according to the power of an outdoor unit, and second-level blockage judgment is carried out according to the variable quantity of the temperature of an indoor coil pipe; third-level blockage judgment is conducted again according to the variable quantity of the temperature of the indoor coil pipe after the frequency is fixed and the rotating speed of the inner draught fan is reduced; finally, fourth-level blockage judgment is conducted again according to the variable quantity of the indoor coil pipe temperature. Multi-dimensional and multi-level judgment is adopted, and indoor coil pipe temperature variation and downshift frequency fixation measures are added, so that the heating blockage judgment precision is improved, and the misjudgment probability is reduced; and meanwhile, risk level judgment and distinguishing are conducted on blockage faults, the compressor is locked to avoid fire blast accidents due to high-risk faults, and the safety is higher.

Description

Technical Field

[0001] The present invention relates to the field of air-conditioning circuit blockage identification, and in particular to a method and system for judging and identifying circuit blockage in a variable frequency air-conditioning heating mode system. Background Art

[0002] The existing air-conditioning system circuit blockage judgment conditions mainly rely on the corresponding temperature difference between the outdoor ambient temperature, the compressor exhaust temperature and the indoor coil temperature for judgment and identification (CN202111371353.9); or use the outdoor ambient temperature, the opening of the electronic expansion valve, the compressor frequency and the temperature difference change rate of the compressor winding temperature to judge the circuit blockage (CN202011460250.5). Or when the air-conditioning system is in heating mode, detect whether the air-conditioning system is blocked; if the air-conditioning system is detected to be blocked, switch the air-conditioning system from heating mode to cooling mode; obtain the operating parameters of the air-conditioning system in cooling mode; determine the type of blockage based on whether the operating parameters of the air-conditioning system in cooling mode are normal, and the blockage types include ice blockage and non-ice blockage (CN202210410855.6).

[0003] In the heating scenario, the outdoor ambient temperature sensor and outdoor unit coil sensor in the above method are easily covered by ice or frozen, making the temperature detection inaccurate, resulting in misjudgment or inaccurate judgment. The judgment and identification method by switching modes is cumbersome, and switching from heating mode to cooling mode may cause discomfort or misunderstanding to some users. Summary of the invention

[0004] In order to improve the accuracy of blockage judgment in heating mode, the present application provides a method and system for judging and identifying system circuit blockage in heating mode of a variable frequency air conditioner.

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

[0006] A method for determining and identifying circuit blockage in a variable frequency air conditioner heating mode system includes:

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

[0008] S110: The compressor continues to run until time b, and 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 speed of the internal fan 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, operate normally.

[0017] Furthermore, the compressor motor winding temperature value TCR_h adopts 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 correct the basic temperature through the correction temperature to obtain the estimated value of the compressor motor winding 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~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.

[0021] Furthermore, the value range of △T1 is 75% to 85%, T1 is 2°C, T2 is 20°C, and K1 is 3%.

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

[0023] Furthermore, when it is determined that the first system loop is blocked, the machine is immediately shut down and the compressor is locked, and is unlocked and restarted after repair; when it is determined that the second system loop is blocked, the machine is shut down for protection, and can be restarted after power is turned on again.

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

[0025] The inverter air conditioner heating mode system circuit blockage judgment and identification system includes:

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

[0027] Power collection unit: used to collect the power value of the outdoor unit;

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

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

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The first level of blockage judgment is made according to the power of the outdoor unit, and the second level of blockage judgment is made according to the change in the indoor coil temperature. After fixing the frequency and reducing the speed of the internal fan, the third level of blockage judgment is made again according to the change in the indoor coil temperature. Finally, the fourth level of blockage judgment is made again according to the change in the indoor coil temperature. Multi-dimensional and multi-level judgment is adopted, and the change in indoor coil temperature and downshift fixed frequency measures are increased to improve the accuracy of heating blockage judgment and reduce the probability of misjudgment. At the same time, the blockage faults are distinguished by risk level, and the compressor is locked for high-risk faults to avoid explosion accidents, which is safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of a method for judging and identifying system circuit blockage in a heating mode of an inverter air conditioner;

[0033] Figure 2 Start the operation data table for normal heating;

[0034] Figure 3 This is the normal heating startup operation curve;

[0035] Figure 4 Start the operation data table for heating circuit blockage;

[0036] Figure 5 This is the start-up operation curve for the heating circuit being blocked;

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

[0038] Figure 7 Preset wind speed and frequency data table for heating blockage. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

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

[0041] S100: The air conditioner is turned on and runs in heating mode. When the compressor starts running for time a, the maximum value of the outdoor unit power Power_max within time a and the indoor coil temperature Tic_a at time a are recorded, where a is the time taken for the outdoor unit power to reach the maximum value when the system is fully blocked or the valve is not opened, and the general value range is 30s to 50s, and the process proceeds to the next step S110.

[0042] S110: The compressor continues to run until time b, where the value range of b is 70s to 90s, and the current power Power_b is obtained. If Power_b / Power_max is less than ΔT1, and ΔT1 is preferably 75% to 85%, then the process proceeds to the next step S120, otherwise the normal operation is maintained.

[0043] If the system is completely blocked or the valve is not open, the power of the outdoor unit will reach its maximum value at the moment the compressor starts. After that, due to the lack of refrigerant flow, the compressor will run at no load and its power will drop significantly (see attached). 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, where 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, where the value range of d is 160s - 180s, preset the current frequency to F1 (preferably the current operating 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 indoor 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 of the following are satisfied simultaneously:

[0049] Power_f > Power_e * K1 and Power_g > Power_f * K1 and Power_h > Power_g * K1, where 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. Since the system loop is blocked, 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, which has 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 door 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 adopts the compressor motor winding temperature estimated value, and there are two methods for obtaining the compressor motor winding temperature estimated value: the first method is to calculate the basic temperature according to the change relationship between magnetic flux and temperature disclosed in the patent document with patent application number 201610808947.4, calculate the corrected temperature according to the relationship between temperature and current, and correct the basic temperature by the corrected temperature to obtain the compressor motor winding temperature estimated value. The second method is to determine the compressor motor winding temperature estimated value based on the magnetic flux change rate and resistance change rate of the motor disclosed in the patent document with patent application number 201910249866.9.

[0053] When the system loop is blocked, there is no effective flow of refrigerant for heat exchange, and the compressor exhaust temperature is low, which cannot truly reflect the internal temperature of the compressor. Therefore, the traditional method of relying on exhaust sensors to judge and identify system blockage will be affected. The present invention utilizes the compressor motor winding temperature estimation technology to estimate the compressor internal motor winding temperature in real time, which is basically equivalent to the measured winding temperature. The blockage judgment is made based on the difference between the estimated compressor motor winding temperature and the exhaust temperature, which is more accurate.

[0054] S150: Continue to run until time i, where the value range of i is 300s to 320s, and determine whether 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 circuit is blocked, and it needs to be shut down for protection. It can be restarted after powering on again. It can also be pushed to the cloud server synchronously to request after-sales service to check the blockage on site. If not, it runs normally.

[0055] It should be noted that the preset values ​​of the present invention can be adjusted according to the blockage experiment. With the judgment method of the present invention, the blockage judgment can be completed about 300 seconds before starting the machine, which is more timely, thereby improving the safety and reliability of the whole machine; the judgment process does not require switching the cooling mode, and the user experience is better.

[0056] The present application also provides a variable frequency air conditioning heating mode system circuit blockage judgment and identification system, comprising:

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

[0058] Power collection unit: used to collect the power value of the outdoor unit;

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

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

[0061] Example

[0062] For the convenience of comparison and explanation, this embodiment also carried out a normal heating start-up operation experiment, and the core parameters such as power of the normal heating start-up operation are shown in the table. Figure 2 , curve see Figure 3 , preset wind speed and frequency data see Figure 6 .

[0063] Under the GB / T7725 standard heating condition, close the air conditioner's stop valve before starting the machine (the small stop valve, the large stop valve, or both stop valves can be closed). This scenario simulates the situation where the air conditioner is installed and the valve is forgotten to be opened, or the air conditioner has not been used for a period of time, resulting in impurity deposition that blocks the system circuit.

[0064] The compressor starts and runs for 35 seconds, and the maximum power Power_max is 661w (see Figure 4 ), after which the power drops rapidly and sharply (see Figure 5 ), which is very different from the normal heating start. The system blocking condition Power / Power_max*100%<△T1 can be triggered in 90S, that is, 428 / 661*100%=64.75%, 64.75%<△T1 (△T1 is preferably 75~85%), and the blocking condition is established.

[0065] Run to about 140s (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, satisfying Tic_c-Tic_a<T1 (T1 is preferably 2°C); continue to run until 180S to fix the preset frequency at 75.9Hz, and reduce the indoor unit wind speed from high speed to medium speed. After running for 200s, take the power of 230s, 260s and 290s continuously, and the power growth rate is less than K1 (3%), and the difference between the estimated value of the compressor motor winding temperature and the exhaust temperature at 290s is less than 20°C, so it does not meet the circuit blockage + mixed air condition (the actual experiment is only circuit blockage, and no mixed air leakage).

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

[0067] By comparison Figure 6 , Figure 7It can be seen that under normal conditions, after fixing the preset frequency and reducing the internal fan speed by one gear, the indoor coil temperature will rise rapidly, the temperature rise can reach at least 5°C, and the difference between the estimated temperature of the compressor motor winding 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 judging and identifying system circuit blockage in a variable frequency air conditioner heating mode, characterized in that: Including: S100: The air conditioner starts 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, 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, 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, preset the current frequency to F1, synchronously drive the speed of the indoor fan to decrease by 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 of the following 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, 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.

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

3. The method for judging and identifying system circuit blockage in the heating mode of a variable frequency air conditioner according to claim 2, characterized in that: The method for obtaining the calculated 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 correct the basic temperature through the correction temperature to obtain the calculated value of the compressor motor winding temperature.

4. The method for judging and identifying system circuit blockage in a variable frequency air conditioner heating mode according to claim 2, characterized in that: The method for obtaining the calculated 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 calculated 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 judging and identifying system circuit blockage in a variable frequency air conditioner heating mode according to claim 1, characterized in that: 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.

6. The method for judging and identifying system circuit blockage in the heating mode of a variable frequency air conditioner according to claim 5, characterized in that: The value range of △T1 is 75% - 85%, T1 is 2°C, T2 is 20°C, and K1 is taken as 3%.

7. The method for judging and identifying system circuit blockage in a variable frequency air conditioner heating mode according to claim 5, characterized in that: F1 is the current operating frequency of the air conditioner at time d.

8. The method for judging and identifying system circuit blockage in a variable frequency air conditioner heating mode according to any one of claims 1 to 7, characterized in that: When it is determined that the first system circuit is blocked, the machine will be shut down immediately and the compressor will be locked. After repair, it will be unlocked and restarted. When it is determined that the second system circuit is blocked, the machine will be shut down for protection and can be restarted after power is turned on again.

9. The method for judging and identifying system circuit blockage in the heating mode of a variable frequency air conditioner according to claim 8, characterized in that: When it is determined that the first system loop is blocked or the second system loop is blocked, the method further includes: pushing the blocking information to a cloud server.

10. A system for judging and identifying circuit blockage in a variable frequency air conditioning heating mode system, characterized in that: include: Time collection unit: used to collect time information; Power collection unit: used to collect the power value of the outdoor unit; Temperature acquisition unit: used to obtain 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 1-9 based on the collected information.

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