An air conditioner indoor fan motor control method

Abstract

The application relates to the technical field of air conditioning equipment, and discloses an air conditioner indoor fan motor control method which protects the compressor and reduces the influence on user comfort during the automatic restart of the indoor fan motor. In the application scheme, a system safe operation time is preset, when the indoor fan motor fault condition is detected, the indoor fan motor is quickly restarted within the system safe operation time, and the compressor and the outdoor fan motor do not stop during the period; after the system safe operation time is exceeded, the compressor and the outdoor fan motor are stopped; within the continuous N times of restart time, the indoor unit does not display a fault code, if the continuous N times of restart are unsuccessful, a direct current motor fault code is displayed and the unit is stopped; the restart interval time is gradually prolonged from the first time to the Nth time; and the fan fault count is cleared after the restart is successful.

Description

Technical Field

[0001] This invention relates to the field of air conditioning equipment technology, and in particular to a method for controlling an indoor fan motor in an air conditioner. Background Technology

[0002] The main components of a typical air conditioner include a display, evaporator, indoor fan motor, indoor unit controller, compressor, outdoor fan motor, condenser, and outdoor unit controller.

[0003] When the indoor fan motor malfunctions, in cooling mode, no cold air will be blown out, and the user will not feel any cooling effect. Furthermore, the inability to remove cold air will cause the evaporator to frost or freeze, resulting in excessively low pressure. This can lead to frost buildup on the compressor casing, causing liquid slugging. In heating mode, no hot air will be blown out, and the user will not feel any heating effect. This can also cause excessively high compressor discharge pressure. Both of these situations can severely damage the air conditioning system and the compressor.

[0004] To distinguish between a "soft fault" caused by environmental interference or a software bug, and a "hard fault" caused by hardware failure, industry-standard control solutions typically restart the indoor fan motor several times when it malfunctions. If the restart is successful, the air conditioner continues to operate; if the restart fails, the air conditioner stops operating, the display shows a fault, and the system awaits repair.

[0005] However, traditional technologies typically employ the following automatic restart schemes for indoor fan motors:

[0006] 1. Restart directly according to the set number of automatic restarts:

[0007] When the indoor fan malfunctions, the indoor unit fan motor takes too long to automatically restart several times. If the compressor is not shut off, liquid slugging will occur in cooling mode, and the compressor discharge pressure will be too high in heating mode. Both of these pose a risk of damaging the air conditioning system and the compressor.

[0008] 2. After turning off the compressor, restart it according to the set number of automatic restarts:

[0009] In this solution, when the indoor fan malfunctions, the compressor stops running immediately, and then the indoor fan motor is automatically restarted. Although this can prevent liquid slugging or excessive compressor pressure, after the compressor stops, it will wait 3-5 minutes before restarting in order to balance the system pressure and prevent overload protection. This will affect the air conditioning's cooling and heating effects and reduce user comfort.

[0010] Furthermore, existing automatic restart schemes for indoor fan motors do not adequately consider the requirements of air conditioner immunity tests. According to Clause 5.2 of GB4343.2-2009 Electromagnetic Compatibility Requirements Part 2: Immunity, air conditioners must undergo various immunity tests, including surge and pulse group tests. The longest test is a 2-minute test on both positive and negative voltages of an electrical fast transient pulse group. Generally, performance criterion C must be met, meaning the fan motor is allowed to temporarily stop during the test but can automatically resume operation afterward. If the indoor fan stops within 2 minutes under pulse group interference conditions and cannot automatically restart after the test, then the test requirements are not met. Summary of the Invention

[0011] The technical problem to be solved by this invention is to propose a control method for an indoor fan motor of an air conditioner, which protects the compressor and reduces the impact on user comfort during the automatic restart of the indoor fan motor.

[0012] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0013] An air conditioner indoor fan motor control method is applied to an air conditioning system, the air conditioning system including a display, an indoor fan motor, an indoor unit controller, a compressor, an outdoor fan motor, and an outdoor unit controller; the display and the indoor fan motor are electrically connected to the indoor unit controller, the compressor and the outdoor fan motor are electrically connected to the outdoor unit controller; the indoor unit controller is electrically connected to the outdoor unit controller.

[0014] The method includes: setting a safe operating time threshold T0, a maximum restart count threshold N for the indoor fan motor, and an interval between each start-up; setting a fault flag A in the communication protocol between the indoor unit controller and the outdoor unit controller, where A=1 indicates a fault in the indoor fan motor and A=0 indicates that the indoor fan motor is operating normally;

[0015] When the indoor fan motor is determined to be in fault mode, control it as follows:

[0016] The indoor fan motor is restarted sequentially according to the set restart interval:

[0017] For restarts within the preset safe operating time threshold T0, the compressor and outdoor fan motor will not stop running. If a restart is successful, the restart will stop and the air conditioner will operate normally.

[0018] For restarts outside the preset safe operating time threshold T0, the compressor and outdoor fan motor will be shut down. If a restart is successful, the restart will be stopped, and the compressor and outdoor fan motor will be shut down and restarted after the shutdown protection phase, and the air conditioner will operate normally.

[0019] If the indoor unit display does not show a fault code within the N restart time period, it will display a fault code and shut down if the restart fails for N consecutive times.

[0020] Furthermore, methods for determining whether an indoor fan motor has entered a fault mode include:

[0021] During the operation of the air conditioning system, the indoor unit controller detects the real-time speed V fed back by the indoor fan motor. S And compare it with the preset fan fault speed threshold V0, if V S If V > V0, the fan is considered to be operating normally; if V S If the value is ≤V0, then the fan is considered to have entered a fault mode.

[0022] Furthermore, the time interval between restarts gradually increases from the first to the Nth restart, i.e., T1 <T2<...T N-1 <T N , among which, T N This represents the time interval between the Nth restart, that is, the delay between the (N-1)th restart and the Nth restart.

[0023] Furthermore, for restarts within the preset safe operating time threshold T0, the fault flag A is set to 0, and the indoor unit controller does not report indoor fan faults to the outdoor unit controller.

[0024] Furthermore, for restarts outside the preset safe operating time threshold T0, the fault flag A is set to 1, and the indoor unit controller reports an indoor fan fault to the outdoor unit controller.

[0025] Furthermore, the following controls are executed during the shutdown protection phase:

[0026] If the air conditioner is in cooling mode, the indoor fan will first return to normal speed, and the compressor and outdoor fan motor will start after the shutdown time reaches the shutdown protection time threshold, and the whole unit will resume normal cooling.

[0027] If the air conditioner is in heating mode, the indoor unit will initially run at a preset low fan speed. It will then start after the compressor and outdoor fan motor reach the shutdown protection time threshold. Once the indoor unit's heat exchanger temperature rises to a certain level, it will resume normal speed.

[0028] Furthermore, T1+T2+...T N-1 +T N >120 seconds.

[0029] The beneficial effects of this invention are:

[0030] (1) A preset safe operating time threshold is set. Within this time, the exhaust temperature and system pressure are within the safe range that the air conditioning system can withstand. Therefore, a quick restart within the safe operating time of the system can eliminate most soft faults while minimizing the impact on user comfort.

[0031] (2) After the system's safe operating time has expired, control the compressor and outdoor fan motor to stop to prevent refrigerant slugging or excessively high exhaust temperature of the heating compressor and excessive system pressure.

[0032] (3) By setting the sum of all restart time intervals to be greater than the pulse group test time (120 seconds), at least one restart occurs 2 minutes after the wind turbine failure, which can avoid interference from the pulse group test and thus identify whether it is a real wind turbine failure. Attached Figure Description

[0033] Figure 1 This is a structural block diagram of the air conditioning system of the present invention;

[0034] Figure 2 This is a flowchart of the air conditioner indoor fan motor control method of the present invention. Detailed Implementation

[0035] This invention aims to provide a control method for an indoor fan motor in an air conditioner, protecting the compressor and reducing the impact on user comfort during the automatic restart of the indoor fan motor. The control method of this invention is applied to air conditioning systems, such as... Figure 1 As shown, the air conditioning system mainly includes a display, an indoor fan motor, an indoor unit controller, a compressor, an outdoor fan motor, and an outdoor unit controller; the display and the indoor fan motor are electrically connected to the indoor unit controller, the compressor and the outdoor fan motor are electrically connected to the outdoor unit controller; and the indoor unit controller is electrically connected to the outdoor unit controller.

[0036] The indoor fan motor features speed feedback, allowing the indoor unit controller to control and acquire its speed. The indoor fan motor includes both AC PG motors and DC motors. The DC motor can be driven internally (IPM or separate IGBT) or externally (with the drive module integrated into the indoor unit controller, and the motor using bare wires).

[0037] According to the air conditioner indoor fan motor control method provided by the present invention, a system safe operating time is preset. When the indoor fan motor fault condition is detected, the indoor fan motor is quickly restarted within the system safe operating time, during which the compressor and outdoor fan motor do not stop. After the system safe operating time is exceeded, the compressor and outdoor fan motor are stopped. During the N consecutive restarts, the indoor unit does not display a fault code. If the N consecutive restarts fail, a DC motor fault code is displayed and the unit stops. The restart interval is gradually extended from the first to the Nth restart. After a successful restart, the fan fault count is reset to zero.

[0038] Specifically, the method first presets a safe operating time threshold T0, a maximum restart count threshold N for the indoor fan motor, and a start-up interval; it then presets a fault flag A in the communication protocol between the indoor unit controller and the outdoor unit controller. When A=1, it indicates a fault in the indoor fan motor; when A=0, it indicates that the indoor fan motor is operating normally.

[0039] The safe operating time threshold T0 can be set based on experience or experiments. Within this time, the exhaust temperature and system pressure are within the safe range that the air conditioning system can withstand. The maximum number of restarts threshold N for the indoor fan motor represents the maximum number of restarts allowed and can be set based on experience or requirements. The start-up time interval should gradually increase from the 1st to the Nth time, and the sum of all time intervals should be greater than the pulse group test time of 120 seconds. This is because during the electrical fast transient pulse group test, even if the indoor fan motor restarts successfully on one occasion, it may be interrupted and stop again. Therefore, setting at least one restart to occur 120 seconds after the fan failure and a pulse group test time exceeding 120 seconds can avoid power interference caused by the experiment and identify whether it is a real hardware failure.

[0040] Based on the above settings, the flowchart of the air conditioner indoor fan motor control method is as follows: Figure 2 ,include:

[0041] During the operation of the air conditioning system, the indoor unit controller detects the real-time speed V fed back by the indoor fan motor. S And compare it with the preset fan fault speed threshold V0, if V S If V > V0, the fan is considered to be operating normally; if V S If the value is ≤V0, then the fan is considered to have entered a fault mode.

[0042] In fault mode, follow these steps:

[0043] S1. First reboot process:

[0044] After time T1, the indoor unit controller restarts the indoor fan motor for the first time. At this time, the display does not show any fault, the fault flag A is set to 0, the indoor unit controller does not report an indoor fan fault to the outdoor unit controller, and the compressor and outdoor fan operate normally. Determine whether the first restart is successful. If it is, the air conditioner operates normally and the process ends; otherwise, proceed to step S2.

[0045] S2, Second restart process:

[0046] After time T2, the indoor unit controller restarts the indoor fan motor for the second time. At this time, the display does not show any fault, the fault flag A is set to 0, the indoor unit controller does not report an indoor fan fault to the outdoor unit controller, and the compressor and outdoor fan operate normally. Determine whether the second restart is successful. If it is, the air conditioner operates normally and the process ends; otherwise, proceed to step S3.

[0047] S3, Third Reboot Process:

[0048] After time T3, a third restart is performed. At this time, the display does not show a fault, flag A is set to 1, and the outdoor unit immediately stops the compressor and outdoor fan motor to prevent liquid slugging. It is determined whether the third restart is successful. If it is, the fault flag is cleared to zero, and the outdoor unit controller controls the compressor and outdoor fan to start after the shutdown protection phase. The air conditioner operates normally, and the process ends. Otherwise, a fourth restart is performed... and so on.

[0049] SN, Nth restart process:

[0050] T N After a certain time, the Nth restart (the last restart) will be performed. During this time, the display will not show any fault, flag A will be set to 1, and the compressor and outdoor fan motor will remain stopped. If the restart is successful, the fault flag will be cleared, and the outdoor unit controller will start the compressor and outdoor fan after the shutdown protection phase. The air conditioner will then operate normally, and the process will end. If the restart fails, the indoor fan motor will not restart, the indoor unit will disconnect power from the outdoor unit, the display will show the indoor fan fault code, and the user will be prompted to report a repair.

[0051] During the above process, if the compressor and outdoor fan motor stop for less than 3 minutes after the indoor unit fan successfully restarts, they are in the shutdown protection phase and the following controls are implemented:

[0052] 1) If the air conditioner is in cooling mode, the indoor fan can first resume normal speed, and the compressor and outdoor fan motor will start after the shutdown time reaches the shutdown protection time threshold (such as 3 minutes), and the whole unit will resume normal cooling.

[0053] 2) If the air conditioner is in heating mode, the indoor unit will initially run at a very low fan speed to prevent the user from being blown by cold air. After the compressor and outdoor fan motor start up after the shutdown protection time threshold (e.g., 3 minutes) is reached, the indoor unit heat exchanger temperature will rise to a certain level and then the normal fan speed will be restored.

[0054] Example:

[0055] In this embodiment, the following presets are made first:

[0056] Based on the experimental results, the preset safe operating time threshold T0 = 20 seconds means that even if the indoor fan motor stops running and only the compressor and outdoor fan motor are running, liquid slugging will not occur during cooling within 20 seconds.

[0057] The indoor fan motor is preset to automatically restart a maximum of 6 times, i.e., N=6, and the first start time T1=5 seconds, the second start interval time T2=10 seconds; the third to sixth start interval time T3-T6 are all 40 seconds.

[0058] At this time: T1+T2+T3+T4+T5+T6=5+10+(6-2)*40=175 seconds. It can be seen that the indoor fan motor has exceeded the 120-second pulse group test time during the 5th and 6th restarts. This can avoid interference from the experiment and identify whether it is a real fan failure.

[0059] Assuming the air conditioner's normal operating speed is V S At speeds above 600 r / min, the actual speed V of the indoor fan motor was detected once. S =80r / min, which is less than the indoor fan fault threshold speed V0 = 100r / min, then the air conditioner is determined to have entered the indoor fan motor fault mode, which specifically includes the following steps:

[0060] Step 1: After 5 seconds, the indoor unit controller restarts the indoor fan motor for the first time. At this time, the display does not show any fault, the flag bit A is set to 0, the indoor unit controller does not report an indoor fan fault to the outdoor unit controller, and the outdoor unit compressor and outdoor fan operate normally. Since T1 = 5 seconds and T0 = 20 seconds, T1 < T0 is satisfied.

[0061] Step 2: The indoor fan motor failed to restart on the first attempt. Proceed to Step 3.

[0062] Step 3: After a 10-second interval, the indoor unit controller restarts the indoor fan motor for the second time. At this time, the display does not show a fault, flag A is set to 0, the indoor unit controller does not report an indoor fan fault to the outdoor unit controller, and the outdoor unit compressor and outdoor fan operate normally. Since T2 = 10 seconds, the following conditions are met: T2 ≥ T1, and T1 + T2 < T0.

[0063] Step 4: The indoor fan motor failed to restart for the second time, proceed to step 5;

[0064] Step 5: After a 40-second interval, the indoor unit controller will automatically restart the indoor fan motor for the third time. At this time, the display will not show any fault, and the outdoor unit will immediately stop the compressor and outdoor fan motor to prevent liquid slugging; at this time, T3 = 40 seconds.

[0065] Step 6: The indoor fan motor failed to restart for the third time, proceeding to Step 7:

[0066] Step 7: After a 40-second interval, the indoor unit controller will automatically restart the indoor fan motor for the fourth time. At this time, the display will not show any fault, and the compressor and outdoor fan motor will remain stopped; at this time, T4 = 40 seconds.

[0067] Step 8: The indoor fan motor has been successfully restarted for the 4th time.

[0068] At this point, the indoor fan motor fault count is reset to zero. The compressor and outdoor fan motor have been off for 80 seconds, from the second failed restart of the indoor fan motor to the fourth successful restart. Since the air conditioner is in cooling mode, the indoor fan immediately resumes normal speed, and the compressor and outdoor fan motor start up after 3 minutes of downtime, and the whole unit resumes normal cooling.

[0069] Finally, it should be noted that the above embodiments are merely preferred embodiments and are not intended to limit the present invention. It should be pointed out that those skilled in the art can make various modifications, equivalent substitutions, and improvements without departing from the spirit and scope of the claims, and all such modifications, substitutions, and improvements should be included within the scope of protection of the present invention.

Claims

1. A method for controlling an indoor fan motor in an air conditioning system, the air conditioning system comprising a display, an indoor fan motor, an indoor unit controller, a compressor, an outdoor fan motor, and an outdoor unit controller; the display and the indoor fan motor are electrically connected to the indoor unit controller, and the compressor and the outdoor fan motor are electrically connected to the outdoor unit controller; The indoor unit controller is electrically connected to the outdoor unit controller; Its features are, The method includes: setting a safe operating time threshold T0, a maximum restart count threshold N for the indoor fan motor, and an interval between each start-up; setting a fault flag A in the communication protocol between the indoor unit controller and the outdoor unit controller, where A=1 indicates a fault in the indoor fan motor, and A=0 indicates that the indoor fan motor is operating normally; When the indoor fan motor is determined to be in fault mode, control it as follows: The indoor fan motor is restarted sequentially according to the set restart interval, with the restart interval gradually increasing from the first to the Nth time, i.e., T1. <T2<...T N-1 <T N And satisfying T1+T2+...T N-1 +T N >120 seconds; where T N This represents the time interval between the Nth restart, that is, the delay between the (N-1)th restart and the Nth restart; For restarts within the preset safe operating time threshold T0, the compressor and outdoor fan motor will not stop running. If a restart is successful, the restart will stop and the air conditioner will operate normally. For restarts outside the preset safe operating time threshold T0, the compressor and outdoor fan motor will be shut down. If a restart is successful, the restart will be stopped, and the compressor and outdoor fan motor will be shut down and restarted after the shutdown protection phase, and the air conditioner will operate normally. If the indoor unit display does not show a fault code within the N restart time period, it will display a fault code and shut down if the restart fails for N consecutive times.

2. The air conditioner indoor fan motor control method as described in claim 1, characterized in that, Methods for determining if an indoor fan motor has entered a fault mode include: During the operation of the air conditioning system, the indoor unit controller detects the real-time speed V fed back by the indoor fan motor. S And compare it with the preset fan fault speed threshold V0, if V S If V > V0, the fan is considered to be operating normally; if V S If the value is ≤V0, then the fan is considered to have entered a fault mode.

3. A method for controlling an indoor fan motor in an air conditioner as described in claim 1 or 2, characterized in that, For restarts within the preset safe operating time threshold T0, the fault flag A is set to 0, and the indoor unit controller does not report indoor fan faults to the outdoor unit controller.

4. The air conditioner indoor fan motor control method as described in claim 3, characterized in that, For restarts outside the preset safe operating time threshold T0, the fault flag bit A is set to 1, and the indoor unit controller reports an indoor fan fault to the outdoor unit controller.

5. A method for controlling an indoor fan motor in an air conditioner as described in claim 1 or 2, characterized in that, The following controls are executed during the shutdown protection phase: If the air conditioner is in cooling mode, the indoor fan will first return to normal speed, and the compressor and outdoor fan motor will start after the shutdown time reaches the shutdown protection time threshold, and the whole unit will resume normal cooling. If the air conditioner is in heating mode, the indoor unit will initially run at a preset low fan speed. It will then start after the compressor and outdoor fan motor reach the shutdown protection time threshold. Once the indoor unit's heat exchanger temperature rises to a certain level, it will resume normal speed.

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