Air conditioner non-stop defrosting frequency control method based on current compensation

Abstract

The invention discloses an air conditioner non-stop defrosting frequency control method based on current compensation, and the method comprises the steps: calculating a difference value delta I, comparing the difference value with a preset threshold value a, carrying out normal frequency reduction according to a comparison result when the current is normal, and carrying out frequency reduction or step-by-step frequency reduction according to a real-time limit value when the current is too large. And by dynamically adjusting the frequency and the current limiting value, stable frequency reduction of the compressor is ensured, the defrosting success rate is improved, normal operation of a unit is ensured, the step S6 serves as a redundancy control mechanism, the defrosting process is effectively prevented from being interrupted, the hardware damage risk is reduced, the overall reliability is improved, temperature fluctuation in the defrosting period can be reduced, and the defrosting efficiency is improved. The heating continuity is maintained, the user experience is optimized, and the current limit value is dynamically corrected, so that the unnecessary frequency rise can be reduced, the energy consumption is reduced, and the energy is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to a method for controlling defrosting frequency of an air conditioner without stopping based on current compensation. Background Art

[0002] The core function of an air conditioner is to adjust the temperature, humidity, air flow rate, and cleanliness of the indoor environment through cooling, heating, dehumidification, ventilation, or air filtration. When a heat pump air conditioner is heating at low temperatures, frost easily forms on the surface of the outdoor heat exchanger due to the low temperature and high humidity, resulting in reduced heating efficiency. In existing technologies, non-stop defrosting methods achieve defrosting by controlling the compressor to reduce frequency, reversing the four-way valve, and increasing the frequency to defrost. The process is as follows: 1. After receiving the defrost command, the compressor reduces the frequency to the preset reversing preparation frequency; 2. Switch the direction of the four-way valve after stable operation for t1 second; 3. Increase the frequency to the defrost frequency to quickly defrost; 4. After defrosting is completed, the frequency is reduced again to the reversing preparation frequency and the four-way valve is switched to resume heating.

[0003] See attached Figure 2 When the compressor drive module is unable to reduce its frequency to the switching preparation frequency due to the low-frequency current limit (set to prevent loss of synchronism), the four-way valve fails to switch, interrupting the defrost process and even preventing the defrost process from exiting. In this case, the compressor may be damaged due to continuous high current operation, liquid backflow, and other factors, while the user's heating experience is poor. Publication number CN108518815A discloses a defrosting method for an air conditioner, comprising: S10: Counting from the second compressor startup, obtaining and storing a first temperature difference of the evaporator within a first preset time; S20: Counting from the next compressor startup, obtaining and storing a second temperature difference of the evaporator within the first preset time; S30: Calculating the absolute value of the difference between the first and second temperature differences; S40: If the absolute value is greater than or equal to the preset difference, executing step S50; otherwise, executing step S60; S50: Performing the defrost operation; S60 includes repeating steps S20 to S40. This method calculates the temperature difference, but cannot prevent poor defrosting due to current issues. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a cardboard heat dissipation and temperature reduction device on a logistics conveyor line with strong practicality and high automation length.

[0005] To achieve the above object, the present invention provides a method for controlling the defrosting frequency of an air conditioner without stopping based on current compensation, comprising the following steps: S1. Preset commutation preparation frequency F_pre, defrost frequency F_defrost, current limit value initial value I, threshold a; S2. If the unit receives a defrost command, the compressor is detected to be in the frequency reduction stage; if the unit does not receive a defrost command, proceed to step S9; S3. If the compressor is in the frequency reduction stage, proceed to step S3; if the compressor is in the frequency increase stage, proceed to step S8; S4. Real-time collection of the compressor operating current I_comp, then calculate the difference ΔI. When ΔI is greater than the threshold a, proceed to step S5. When ΔI is less than or equal to the threshold a, the compressor normal speed is reduced to F_pre, and then proceed to step S7. S5. Calculate the correction coefficient K (K = α × T_out + β × P_high) based on T_out and P_high, dynamically update the limit value I_new = I × K, and then reduce the frequency within time t2. If the frequency reduction to F_pre is successful, proceed to step S7. If the frequency reduction to F_pre fails, proceed to step S6. S6. Perform step-by-step frequency reduction within t3. If the frequency reduction to F_pre2 fails, the compressor is shut down for a short time, and then restarted, and proceeds to step S5. If the frequency reduction to F_pre2 is successful, proceeds to step S7. S7. The compressor runs stably for t1 time, then the four-way valve is switched, and then the defrost is detected. If defrost is completed, the unit resumes normal heating and proceeds to step S9. If defrost is not completed, proceed to step S8. S8. The compressor frequency is increased to F_defrost to continue defrosting and proceed to step S4.

[0006] S9. The unit is operating normally.

[0007] The beneficial effects of the present invention are: high defrost success rate and low energy consumption. The method calculates the difference ΔI and compares the difference with a preset threshold value a. According to the comparison result, normal frequency reduction is performed when the current is normal. When the current is too large, the frequency is reduced according to the real-time limit, or the frequency is reduced in steps to avoid commutation failure caused by excessive current. By dynamically adjusting the frequency and current limit values, the compressor can be stably reduced in frequency, the defrost success rate can be improved, and the normal operation of the unit can be guaranteed. Step S6 serves as a redundant control mechanism to effectively prevent interruption of the defrost process, reduce the risk of hardware damage, and improve overall reliability. It can also reduce temperature fluctuations during defrost, maintain heating continuity, and optimize user experience. In addition, by dynamically correcting the current limit value, unnecessary frequency increases can be reduced, energy consumption can be reduced, and energy can be saved.

[0008] Furthermore, in step S1, the threshold a∈[-0.5,0)}.

[0009] Furthermore, in step S4 , ΔI is the difference between I_comp and I.

[0010] Furthermore, in step S4, the ambient temperature T_out and the system high-pressure side pressure P_high are collected in real time.

[0011] Furthermore, in step S6, the frequency of the step-by-step frequency reduction is to run stably for 2-5 seconds at every 5 Hz interval.

[0012] Furthermore, in step S6, the short-term shutdown is a shutdown of 5-10 seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Flowchart of the present invention.

[0014] Figure 2 This is a defrost timing diagram of the prior art. DETAILED DESCRIPTION

[0015] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] See attached Figure 1 To the attached Figure 2 As shown, a method for controlling the defrosting frequency of an air conditioner without stopping based on current compensation includes the following steps: S1. Preset the commutation preparation frequency F_pre, the defrost frequency F_defrost, the initial value of the current limit value I, and the threshold a, where the threshold a∈[-0.5,0)}.

[0018] S2. If the unit receives a defrost command, it detects whether the compressor is in the frequency reduction stage; if the unit does not receive a defrost command, it proceeds to step S9.

[0019] S3. If the compressor is in the frequency reduction stage, proceed to step S3; if the compressor is in the frequency increase stage, proceed to step S8.

[0020] S4. Real-time collection of ambient temperature T_out, system high-pressure side pressure P_high, and compressor operating current I_comp. Calculate the difference ΔI, which is the difference between I_comp and I. Adjust the target frequency reduction rate based on ΔI to avoid current exceeding the limit and triggering forced frequency increase. When ΔI is greater than threshold a, enter the current limit compensation stage and proceed to step S5. When ΔI is less than or equal to threshold a, reduce the compressor's normal speed to F_pre, and then proceed to step S7.

[0021] S5. Calculate the correction coefficient K (K = α × T_out + β × P_high) based on T_out and P_high, dynamically update the limit value I_new = I × K, and then reduce the frequency within time t2. If the frequency reduction to F_pre is successful, continue to step S7. If the frequency reduction to F_pre fails, trigger the standby defrost mode and proceed to step S6.

[0022] S6. Perform step-by-step frequency reduction within time t3. If the frequency reduction to F_pre2 fails, the compressor is temporarily shut down, and then restarted, and step S5 is performed. If the frequency reduction to F_pre2 is successful, step S7 is performed.

[0023] F_pre2 is the secondary frequency, which is higher than F_pre but lower than the current operating frequency, such as F_pre2 = F_pre + 5Hz. F_pre2 cannot be set too high, otherwise there will be noise problems and the risk of damaging the four-way valve. It is preferably reduced to the suboptimal frequency F_pre2 at a rate of 1Hz / S to ensure that the defrost process is forced to complete.

[0024] S7. The compressor runs stably for t1 time, then the four-way valve is reversed, and then it is detected whether defrosting is completed. If defrosting is completed, the unit repeats the frequency reduction and reversing process to resume heating and proceeds to step S9. If defrosting is not completed, proceed to step S8.

[0025] S8. The compressor frequency is increased to F_defrost to continue defrosting and proceed to step S4.

[0026] S9. The unit is operating normally.

[0027] In this embodiment, step S6 is a standby defrost mode, a fault redundancy control mechanism, and effectively forces defrost to proceed.

[0028] In this embodiment, the alternative to defrosting by stopping the compressor completely is to perform defrosting, but this will result in heating interruption, poor user experience, and increased energy consumption.

[0029] Optimizing the switching timing of the four-way valve: adjusting the stable operation time t1 before switching, but it cannot fundamentally solve the frequency reduction failure problem caused by current limitation.

[0030] Hardware upgrade solution: Use a higher-performance compressor drive module to relax current limits, but the cost increases significantly.

[0031] Therefore, compared with the traditional technology, this embodiment can fundamentally solve the problem of frequency reduction failure caused by current limitation, has lower energy consumption, is easier for users to replace, and has low cost.

[0032] In the attached Figure 2 Where, t=[tfan early stop time], t1=[t1 reversing preparation time].

[0033] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any person skilled in the art can, without departing from the scope of the present invention, utilize the technical content disclosed above to make further possible variations and modifications to the present invention, or modify the present invention into equivalent embodiments with equivalent variations. Therefore, any equivalent variations made in accordance with the principles of the present invention without departing from the content of the present invention's technical solution should be included within the scope of protection of the present invention.

Claims

1. A method for controlling defrosting frequency of an air conditioner without stopping based on current compensation, characterized in that: The following steps are involved: S1. Preset commutation preparation frequency F_pre, defrost frequency F_defrost, current limit value initial value I, threshold a; S2. If the unit receives a defrost command, the compressor is detected to be in the frequency reduction stage; if the unit does not receive a defrost command, proceed to step S9; S3. If the compressor is in the frequency reduction stage, proceed to step S3; if the compressor is in the frequency increase stage, proceed to step S8; S4. Real-time collection of the compressor operating current I_comp, then calculate the difference ΔI. When ΔI is greater than the threshold a, proceed to step S5. When ΔI is less than or equal to the threshold a, the compressor normal speed is reduced to F_pre, and then proceed to step S7. S5. Calculate the correction coefficient K (K = α × T_out + β × P_high) based on T_out and P_high, dynamically update the limit value I_new = I × K, and then reduce the frequency within time t2. If the frequency reduction to F_pre is successful, proceed to step S7. If the frequency reduction to F_pre fails, proceed to step S6. S6. Perform step-by-step frequency reduction within t3. If the frequency reduction to F_pre2 fails, the compressor is shut down for a short time, and then restarted, and proceeds to step S5. If the frequency reduction to F_pre2 is successful, proceeds to step S7. S7. The compressor runs stably for t1 time, then the four-way valve is switched, and then the defrost is detected. If defrost is completed, the unit resumes normal heating and proceeds to step S9. If defrost is not completed, proceed to step S8. S8. The compressor frequency is increased to F_defrost to continue defrosting and proceed to step S4. 2.S9. The unit is operating normally.

3. The method for controlling defrosting frequency of an air conditioner without stopping based on current compensation according to claim 1, characterized in that: In step S1, the threshold a∈[-0.5,0)}.

4. The method for controlling defrosting frequency of an air conditioner without stopping based on current compensation according to claim 1, characterized in that: In step S4 , ΔI is the difference between I_comp and I.

5. The method for controlling defrosting frequency of an air conditioner without stopping based on current compensation according to claim 1, characterized in that: In step S4, the ambient temperature T_out and the system high-pressure side pressure P_high are collected in real time.

6. The method for controlling defrosting frequency of an air conditioner without stopping based on current compensation according to claim 1, characterized in that: In step S6, the frequency of the step-by-step frequency reduction is to run stably for 2-5 seconds at every 5 Hz interval.

7. The method for controlling defrosting frequency of an air conditioner without stopping based on current compensation according to claim 1, characterized in that: In step S6, the short shutdown is a shutdown of 5-10 seconds.

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