Control method of a refrigeration control system

Abstract

The present application relates to the field of refrigeration control, in order to realize the safety and energy saving control of refrigeration control system, provide the control method of refrigeration control system, including: starting control and energy saving control, the energy saving control includes defrosting control and electric quantity optimization control, the starting control includes: step 1, compressor power on, record the maximum current Imax in the preset time during starting process;Step 2, according to the judgment condition, the current I in subsequent t time is judged in real time: step 3, after starting failure, stop for a period of time, adjust the judgment condition in step 2, and repeat step 1, 2, until starting success or the number of starting failure exceeds the failure threshold value. The above-mentioned mode realizes the safety and energy saving control of refrigeration control system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration control, and particularly relates to a control method of a refrigeration control system. BACKGROUND

[0002] With the continuous development of the Internet economy, prefabricated food, biological medicine, quick-frozen food and the like have higher requirements for cold chain systems in terms of cold speed, energy saving and reliability.

[0003] Traditional refrigerator, freezer, display cabinet and the like terminal refrigeration systems have the following pain points:

[0004] Each time, 5 minutes of downtime is required before the system can be used again, which is not conducive to the quick start and stop control of the refrigeration system.

[0005] The protector parameters are not stable in actual matching with the motor, and the protection capability is reduced; and the protection current fluctuation range is up to 30% and the protection temperature fluctuation range is up to 10% due to the influence of the production process, resulting in insufficient protection capability of the compressor when it is abnormally working. When the current characteristics of the compressor change with the increase of the service life, the protection capability of the protector is insufficient.

[0006] In addition, the existing protectors and starters have many types and poor standardization, which brings great inconvenience to procurement, production and maintenance. SUMMARY

[0007] In order to realize the safety and energy saving control of the refrigeration control system, the present application provides a control method of a refrigeration control system.

[0008] The technical solution adopted by the present application to solve the above problems is:

[0009] The control method of the refrigeration control system comprises: start control and energy saving control, the energy saving control comprises defrosting control and electric quantity optimization control, and the start control comprises:

[0010] Step 1, power on the compressor, and record the maximum current Imax in the preset time during the start process;

[0011] Step 2, real-time judge the current I in the subsequent t time:

[0012] If t < t 阈值 , and I ≤ Imax × P, 0.65 ≤ P ≤ 0.85, then disconnect the electronic start switch, the compressor normally runs, the voltage, the maximum current and the time when the electronic start switch is disconnected in this process are recorded, it is noted that the start is successful, and the number of start failures is cleared to zero;

[0013] If t < t 阈值, if 0.65≤P≤0.85 is not reached, turn off the compressor power supply, record the voltage, the maximum current, the time when the electronic starting switch is turned off as t 阈值 , and note that the starting fails once.

[0014] Step 3, after the starting fails, stop for a period of time, adjust t 阈值 in step 2 to t 阈值 +Δt, and repeat steps 1 and 2 until the starting succeeds or the number of starting failures exceeds a failure threshold.

[0015] Further, the preset time in step 1 is 0.1s, and the failure threshold in step 3 is 4.

[0016] Further, in step 2, when the compressor is powered on for the first time, t 阈值 =3s; when the compressor is powered on for the second time, t 阈值 =5s; when the compressor is powered on for the third time, t 阈值 =7s; and when the compressor is powered on for the fourth time, t 阈值 =10s.

[0017] Further, in step 3, after the starting fails for the first time, stop for 2 minutes; after the starting fails for the second time, stop for 5 minutes; and after the starting fails for the third time, stop for 15 minutes.

[0018] Further, in step 3, when the number of starting failures exceeds the failure threshold, the system issues an alarm.

[0019] Further, the starting control further comprises: step 4, using the minimum starting current corresponding to different voltages when the starting succeeds to protect the motor winding temperature during the starting process, and using the minimum voltage value when the starting continuously fails to protect the voltage during the starting process.

[0020] Further, the defrosting control is:

[0021] A. Monitor the evaporator inlet temperature and the evaporator outlet temperature, calculate the temperature difference between the evaporator inlet and the evaporator outlet, and perform defrosting once when the temperature difference exceeds a defrosting preset value.

[0022] B. Monitor the total door opening time, and perform defrosting once when the total door opening time reaches a door opening preset value.

[0023] Further, the power optimization control is:

[0024] C. According to different ambient temperatures, preset different starting and stopping strategies.

[0025] D. Monitor the actual condensing temperature and adjust the condensing fan speed.

[0026] Further, the control method further comprises: intelligent life detection, the intelligent life detection comprising start-stop ratio monitoring and power monitoring,

[0027] The start-stop ratio monitoring is: presetting corresponding start-stop ratios according to different ambient temperatures; when the start-stop ratio is abnormal, defrosting is performed once, and if it cannot be restored, an alarm is given.

[0028] The power monitoring is:

[0029] According to different ambient temperatures, preset corresponding start-up power, when the start-up power is large and shows a gradual upward trend, an alarm is given.

[0030] In the power monitoring process, in addition to the start-up process, if the power suddenly decreases, an alarm is given.

[0031] The present application has the beneficial effects compared with the prior art: using the circuit board composed of MCU, voltage sensor, current sensor and other electronic components, through special operation and starting strategy, the starting success or failure is accurately and intelligently identified, and it is safer to use. By actively recording the current and voltage of the motor starting success or failure, synchronous analysis, self-learning, automatic adaptation to different types of compressor motors are realized. Through normal use of the user, the starting control strategy is self-improved, which can adapt to different use environments to a certain extent; using the communication system to actively report the starting failure can effectively protect the high-value properties of the user such as vaccines, medicines, etc. In addition, defrosting control, power optimization control and intelligent life detection can be realized, which is safer and more energy-saving to use. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a control method architecture diagram of the refrigeration control system;

[0033] Figure 2 It is a starting control flow chart. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0035] As shown in Figure 1 The control method of the refrigeration control system comprises: starting control and energy-saving control, the energy-saving control comprising defrosting control and power optimization control, as shown in Figure 2 The starting control comprises:

[0036] Step 1, the compressor is powered on, and the maximum current Imax in the preset time during the starting process is recorded; in this embodiment, the preset time is 0.1s.

[0037] Step 2, real-time judgment is made on the current I in the subsequent t time:

[0038] If t < t 阈值 , and I ≤ Imax × P, 0.65 ≤ P ≤ 0.85, the electronic starting switch is turned off, the compressor is normally operated, the voltage, the maximum current and the time when the electronic starting switch is turned off in this process are recorded, it is noted that the starting is successful, and the number of starting failures is cleared;

[0039] If t < t 阈值 , 0.65 ≤ P ≤ 0.85 cannot be reached, the power supply of the compressor is turned off, the voltage, the maximum current and the time when the electronic starting switch is turned off in this process are recorded as t 阈值 , it is noted that the starting fails once;

[0040] Step 3, after the starting fails, the machine is stopped for a period of time, t 阈值 in step 2 is adjusted to t 阈值 + Δt, and steps 1 and 2 are repeated until the starting is successful or the number of starting failures exceeds the failure threshold.

[0041] After failing once, the machine is stopped for 2 minutes, the power is turned on for the second time, the maximum current Imax in 0.1s is recorded again, t 阈值 is adjusted to 5s, P remains unchanged; if the starting is successful, the voltage, the maximum current and the time when the electronic starting switch is turned off in this process are recorded, it is noted that the starting is successful, and the number of starting failures is cleared. If the starting fails, the voltage, the maximum current and the time when the electronic starting switch is turned off in this process are recorded as 4s, it is noted that the starting fails twice. 4s is uniformly recorded by referring to the national standard blocked rotation judgment, so as to facilitate the background to judge whether the compressor motor has abnormal conditions such as short circuit and open circuit.

[0042] After failing twice, the machine is stopped for 5 minutes, the power is turned on for the third time, the maximum current Imax in 0.1s is recorded again, t 阈值 is adjusted to 7s, P remains unchanged. If the starting is successful or fails, the data is judged and recorded according to the previous strategy.

[0043] After failing three times, the machine is stopped for 15 minutes, the power is turned on for the fourth time, t 阈值 is adjusted to 10s. The data is recorded synchronously.

[0044] In subsequent power-on attempts, the machine is stopped for 15 minutes, t 阈值 remains 10s. If the starting is successful, the number of continuous failures is cleared. If the number of continuous failures exceeds 4 times, an alarm is given. In this embodiment, the communication system is used to notify the relevant personnel to realize manual active intervention maintenance, including remote recovery operation or on-site service.

[0045] Adopting the above starting control mode, whether the terminal user uses abnormally, the use environment is too harsh, the compressor is damaged, or the system leaks refrigerant can be effectively judged, so that the after-sales can effectively intervene.

[0046] Further, the starting control further comprises: automatically counting the minimum starting current value under different voltages when starting is successful, taking it as a learning value for motor winding temperature protection in the starting process. After a certain period of time, such as 1 month, the motor winding temperature protection function in the starting process is turned on. That is, when the current value < learning value corresponding to the starting voltage V, stop for 15 minutes in order to cool the compressor motor.

[0047] Automatically count the minimum voltage value V when continuous starting fails 小 as a learning value for voltage protection in the starting process, and must satisfy V 小 ≤ 0.85V 额定 After a certain period of time, such as 1 month, the voltage protection function in the starting process is turned on. If V 小 ≤ 0.85V 额定 does not appear, the voltage protection is delayed.

[0048] In the subsequent use process, once the motor winding temperature protection or voltage protection is triggered, whether it is restored or not, the user and the staff are automatically informed, and the user is guided by the staff to troubleshoot voltage or other abnormal conditions.

[0049] The stator current is collected through the current sampling circuit, and after signal processing, the stator voltage frequency signal and the difference frequency signal (Hz) are obtained, and then the slip of the asynchronous motor is calculated.

[0050] After starting successfully, the running process protection strategy is turned on, and when the slip is greater than a certain value, such as 12%, the running process protection is performed. For example, when the actual running speed is 2650 rpm while the motor synchronous speed is 3000 rpm, protection is performed to avoid the risk of motor burnout caused by motor overload operation.

[0051] The defrosting control is:

[0052] A. Monitor the evaporator inlet temperature and the evaporator outlet temperature, calculate the temperature difference between the evaporator inlet and outlet, and when the temperature difference exceeds the defrosting preset value, perform defrosting once;

[0053] B. Monitor the total door opening time, and when the total door opening time reaches the door opening preset value, perform defrosting once.

[0054] The above method can realize precise defrosting control and reduce energy consumption.

[0055] The power optimization control is:

[0056] C. According to different ambient temperatures, preset different start and stop strategies;

[0057] D. Monitor the actual condensing temperature and adjust the condensing fan speed. For example, when the ambient temperature is higher and the condenser is dusty, the condensing temperature T1 will be higher than the design value T0. At this time, the system refrigeration capacity will decrease, and the system pressure will rise, which will increase the risk of refrigerant leakage. At this time, the condensing fan speed is increased to ensure normal refrigeration of the system and reduce the system pressure. When T1 < T0, the condensing fan speed is reduced to save power.

[0058] Further, the control method further comprises intelligent life detection, wherein the intelligent life detection comprises start-stop ratio monitoring and power monitoring,

[0059] The start-stop ratio monitoring is that according to different ambient temperatures, corresponding start-stop ratios are preset; when the start-stop ratio is abnormal, defrosting is performed once, and if it cannot be restored, an alarm is given; the staff can determine the failure mode according to the big data comparison result, such as seal aging, refrigerant leakage, condenser dust, and compressor suction and exhaust valve fatigue, and give an early warning of the decline of the refrigeration capacity of the refrigeration system.

[0060] The power monitoring is that:

[0061] According to different ambient temperatures, corresponding start-stop ratios are preset; when the start-stop ratio is abnormal, defrosting is performed once, and if it cannot be restored, an alarm is given; the staff can determine the failure mode according to the big data comparison result, such as seal aging, refrigerant leakage, condenser dust, and compressor suction and exhaust valve fatigue, and give an early warning of the decline of the refrigeration capacity of the refrigeration system.

[0062] In the power monitoring process, in addition to the start-up process, if the power suddenly decreases, it is predicted that the refrigerant leaks rapidly, and the power is immediately cut off and the user is notified.

Claims

1. A control method of a refrigeration control system, characterized by, The application relates to a control method for a compressor, which comprises: a start control and an energy-saving control, wherein the energy-saving control comprises a defrosting control and an electric quantity optimization control, and the start control comprises: Step 1: power-on of the compressor, and recording of the maximum current Imax in a preset time during the starting process; Step 2: real-time judgment of the current I in the subsequent t time; If t < t0, and I > Imax x P, 0.65 < P < 0.85, then the electronic starting switch is turned off, the compressor is normally operated, the voltage, the maximum current and the time when the electronic starting switch is turned off in this process are recorded, it is remarked that the starting is successful, and the number of starting failures is cleared. If t < t0, and I > Imax x P, 0.65 < P < 0.85, then the electronic starting switch is turned off, the compressor is normally operated, the voltage, the maximum current and the time when the electronic starting switch is turned off in If t , if 0.65≤P≤0.85 is not reached, the compressor power is disconnected, the voltage, the maximum current, and the time when the electronic starting switch is disconnected during this process are recorded , and it is noted that the starting fails once; Step 3, after startup failure, stop for a period of time, adjust step 2 in To And repeat steps 1, 2 until the startup is successful or the number of startup failures exceeds the failure threshold; The control method further comprises an intelligent life detection, which comprises an open-stop ratio monitoring and a power monitoring, The open-stop ratio monitoring is that corresponding open-stop ratios are preset according to different environmental temperatures; when the open-stop ratio is abnormal, defrosting is carried out once, and if the open-stop ratio cannot be restored, an alarm is given; The power monitoring is that: corresponding starting powers are preset according to different environmental temperatures, and when the starting power is large and shows a gradually increasing trend, an alarm is given; in the power monitoring process, an alarm is given when the power suddenly decreases except in the starting process.

2. The control method of the refrigeration control system according to claim 1, characterized by, The preset time in the step 1 is 0.1s, and the failure threshold value in the step 3 is 4.

3. The control method of the refrigeration control system according to claim 2, characterized by, In step 2, the compressor is powered on for the first time, ; the compressor is powered on for the second time, ; the compressor is powered on for the third time, ; the compressor is powered on for the fourth time, .

4. The control method of the refrigeration control system according to claim 3, characterized by, In the step 3, the compressor is stopped for 2min after the first starting failure, stopped for 5min after the second starting failure, and stopped for 15min after the third starting failure.

5. The control method of the refrigeration control system according to claim 1, characterized by, In the step 3, when the number of starting failures exceeds the failure threshold value, the system gives an alarm.

6. The control method of the refrigeration control system according to claim 1, characterized by, The start control further comprises:

7. The control method of the refrigeration control system according to claim 1, characterized by, Step 4: the minimum starting current corresponding to different voltages when starting is successful is used for motor winding temperature protection in the starting process, and the minimum voltage value when starting continuously fails is used for voltage protection in the starting process. The defrosting control is that: A. the evaporator inlet temperature and the evaporator outlet temperature are monitored, the temperature difference between the evaporator inlet and the evaporator outlet is calculated, and when the temperature difference exceeds a defrosting preset value, defrosting is carried out once; 8. The control method of the refrigeration control system according to claim 1, characterized by, B. the total door opening time is monitored, and when the total door opening time reaches a door opening preset value, defrosting is carried out once. The electric quantity optimization control is that: C. different starting and stopping strategies are preset according to different environmental temperatures; D. the actual condensing temperature is monitored, and the condensing fan rotating speed is adjusted.

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