Control method for preventing compressor from frequent temperature-reaching shutdown

Abstract

The invention relates to a control method for preventing a compressor from frequent temperature-reaching shutdown, which comprises the following steps: acquiring a difference value delta T1 between an actual heating temperature Tr and a set heating temperature Tset at the current moment, and determining a starting working frequency gear Fb according to a working frequency gear Fi corresponding to a temperature difference interval in which the difference value delta T1 is located; and if the difference value delta T1 is within a set temperature difference interval in which environment temperature correction needs to be carried out, environment temperature correction is further carried out on the working frequency gear Fi corresponding to the temperature difference interval, and a starting working frequency gear Fb is obtained. And the compressor is started at the working frequency corresponding to the starting working frequency gear Fb, and after timing of the TM period is finished, frequency increasing, frequency decreasing or shutdown of the compressor is judged according to the relation of the actual heating temperature Tr, the set frequency decreasing temperature Tj and the set shutdown temperature Tt at the current moment and the relation of the actual change value delta Tr and the set change value delta Tset of the actual heating temperature Tr in the TM period. The compressor can be prevented from being frequently started and stopped due to the fact that the compressor is rapidly heated and is triggered to stop at the temperature again.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor operation, and in particular to a control method for preventing a compressor from frequently shutting down due to overtemperature. Background Art

[0002] In a heat pump system, when the compressor starts, a large mechanical and electrical shock will be generated when the compressor accelerates directly from a stationary state to a high-speed operation. Therefore, when the compressor restarts, it usually runs at a lower platform frequency (also called the starting frequency) and then quickly increases to a higher or maximum operating frequency.

[0003] In the prior art, especially in heat pump systems, the compressor may temporarily shut down when the water temperature reaches the set temperature. Specifically, when the compressor starts to work, it will first run at a lower starting frequency, and then quickly increase the frequency to the set higher or highest operating frequency (target frequency). The water temperature continues to rise in this process. Once the water temperature reaches the set temperature, the compressor will reduce the frequency and work at a lower operating frequency to maintain the water temperature. However, in most cases, when the compressor works at the highest operating frequency, the water temperature will rise rapidly and the temperature difference between the water temperature and the set temperature will be too high, which can easily trigger a temperature shutdown. The compressor will stop working. As the water temperature gradually drops and falls below the set value, the compressor will restart.

[0004] However, if the compressor is restarted after being triggered by temperature shutdown, and the compressor is still controlled to operate according to the operating frequency before the shutdown, the water temperature may quickly rise to the set temperature, and then trigger the compressor to reduce frequency or shut down. If the frequency reduction speed is not fast enough to respond to the temperature change in time, the compressor may shut down quickly again. In this process, the water temperature rises and falls frequently, seriously affecting the user's comfort experience. Summary of the invention

[0005] Based on this, the purpose of the present invention is to overcome the defects or shortcomings of the prior art and provide a control method to prevent the compressor from frequently shutting down due to over-temperature.

[0006] A control method for preventing a compressor from frequently shutting down due to overtemperature, comprising:

[0007] Get the actual heating temperature T at the current moment r and set heating temperature T set The difference ΔT1, according to the temperature difference range where the difference ΔT1 is located, the corresponding operating frequency level F i Determine the starting operating frequency gear F b If the difference ΔT1 is within the set temperature difference range that needs to be corrected, the operating frequency level F corresponding to the temperature difference range is further adjusted. i Perform ambient temperature correction to obtain the starting operating frequency gear Fb .

[0008] The compressor starts at operating frequency level F b The corresponding working frequency is started. After the TM cycle timing ends, according to the actual heating temperature T at the current moment r , set the frequency reduction temperature T j , Set the shutdown temperature T t and the actual heating temperature T in the TM cycle r The actual change value ΔT r , set the change value ΔT set The relationship between the compressor frequency increase, frequency reduction or shutdown is determined:

[0009] If the actual heating temperature T r Less than the set heating temperature T set , and the actual change value ΔT r ≤Setting change value ΔT set When the compressor starts working at frequency level F b Increase one gear until it reaches the highest frequency gear F 10 ;

[0010] If the actual heating temperature T r Greater than the set frequency reduction temperature T j , compressor starting operating frequency gear F b Downgrade one gear until it reaches the lowest frequency gear F0;

[0011] If the actual heating temperature T r Greater than the set shutdown temperature T t , the compressor is triggered to temperature shutdown;

[0012] The set shutdown temperature T t Greater than the set frequency reduction temperature T j .

[0013] Compared with the prior art, the control method for preventing the compressor from frequently shutting down due to overtemperature described in the present invention can prevent the compressor from rapidly heating up and triggering the overtemperature shutdown again, resulting in frequent start and stop of the compressor, which in turn has a negative impact on the efficiency, life and stability of the equipment and increases energy consumption and operating costs.

[0014] The temperature difference interval includes multiple temperature difference intervals. As the temperature difference values ​​included in the temperature difference intervals continue to increase, the operating frequency level of the compressor also increases accordingly.

[0015] The ambient temperature correction is to obtain the current ambient temperature T a , according to the ambient temperature T a The temperature range determines the corresponding correction frequency gear value n, and then starts the working frequency gear Fb F i+n .

[0016] The temperature interval includes multiple temperature intervals. As the temperature values ​​included in the temperature intervals increase continuously, the correction frequency level value n also decreases accordingly.

[0017] The set frequency reduction temperature T j Set the heating temperature T set The sum of the shutdown hysteresis LD, where the shutdown hysteresis LD ranges from 0 to 10°C, and its specific value depends on the user's needs and system characteristics.

[0018] The set shutdown temperature T t Set the heating temperature T set Add 2°C to the sum of the shutdown hysteresis LD, where the shutdown hysteresis LD value range is 0 to 10°C, and its specific value depends on the user's needs and system characteristics.

[0019] The working frequency level F i The i in the formula is an integer ranging from 0 to 10. F0 represents the lowest operating frequency. 10 Indicates the highest operating frequency gear.

[0020] Specifically, the temperature difference intervals include a first temperature difference interval, a second temperature difference interval, a third temperature difference interval and a fourth temperature difference interval; wherein the first temperature difference interval is 0°C≤ΔT1<5°C, and its corresponding operating frequency gear F i F0; the second temperature difference range is 5℃≤ΔT1<10℃, and its corresponding working frequency gear is F i The third temperature difference range is 10℃≤ΔT1<15℃, and its corresponding working frequency level is F i The fourth temperature difference range is ΔT1 ≥ 15°C, and its corresponding operating frequency level is F i F 10 .

[0021] Specifically, when the difference ΔT1 is within the first temperature difference range and the fourth temperature difference range, the starting working frequency gear F b Equal to the operating frequency level F i , respectively F0 and F 10 When the difference ΔT1 is in the second temperature difference range or the third temperature difference range, the operating frequency gear F i Perform ambient temperature correction to obtain the starting operating frequency gear F b .

[0022] The ambient temperature correction is to obtain the current ambient temperature T a , according to the ambient temperature T aThe temperature range determines the corresponding correction frequency gear value n, and the starting working frequency gear F is obtained. b F i+n .

[0023] Specifically, the temperature interval includes a first temperature interval, a second temperature interval, a third temperature interval and a fourth temperature interval; wherein the first temperature interval is T a <-15℃, the corresponding correction frequency gear value n is 3; the second temperature range is -15℃≤T a <0℃, the corresponding correction frequency gear value n is 2; the third temperature range is 0℃≤T a <15℃, the corresponding correction frequency gear value n is 0; the fourth temperature range is T a ≥15℃, the corresponding correction frequency gear value n is -1.

[0024] Specifically, when the difference ΔT1 is in the second temperature difference range and the third temperature difference range, the starting working frequency gear F b F 3+n and F 7+n ; The value of n is determined by the ambient temperature correction.

[0025] Specifically, the TM period ranges from 0 to 10 minutes, preferably 5 minutes.

[0026] Specifically, the heating temperature T is set in the TM cycle. set The change value ΔT set The value range is 0 to 5°C, and the shutdown hysteresis LD value range is 0 to 10°C. The specific value of each parameter depends on the user's needs and the characteristics of the system.

[0027] Specifically, the compressor frequency upshift, downshift and temperature shutdown will only be judged and executed when the TM cycle timing ends.

[0028] Specifically, when the compressor is defrosted, the control method for preventing the compressor from frequently shutting down due to overtemperature is stopped to adjust the compressor operating frequency. After the defrosting operation is completed, the compressor operating frequency level must be restored to that before defrosting, and the control method for preventing the compressor from frequently shutting down due to overtemperature is started only after the compressor has run for 5 minutes.

[0029] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flow chart of a control method for preventing a compressor from frequently shutting down due to over-temperature conditions. DETAILED DESCRIPTION

[0031] When the compressor is restarted after being triggered by temperature shutdown, in order to prevent the compressor from being controlled according to the operating frequency before shutdown, the water temperature may quickly rise to the set temperature and then trigger the compressor to reduce frequency or shut down. Before the compressor works, the target frequency is corrected by detecting the ambient temperature, actual heating temperature and set heating temperature.

[0032] According to the difference between the actual heating temperature of the water tank and the set heating temperature, the heating process is divided into multiple temperature rise sections. In each temperature rise section, the variable frequency compressor adopts a different working frequency. This can more finely control the working frequency of the compressor to adapt to different heating requirements and environmental conditions. At the same time, the impact of ambient temperature on the heat pump system is considered. When the ambient temperature is too low, the compressor operating frequency needs to be increased accordingly. When the ambient temperature is too high, the compressor operating frequency needs to be reduced accordingly.

[0033] The present invention can prevent the compressor from rapidly heating up and triggering a temperature shutdown again, causing the compressor to start and stop frequently, thereby negatively affecting the efficiency, life and stability of the equipment and increasing energy consumption and operating costs.

[0034] The scheme of the present invention is described in detail below with reference to the accompanying drawings.

[0035] The heat pump system includes a compressor, a condenser, an electronic expansion valve and an evaporator connected in sequence by a refrigerant circulation pipeline. The condenser is a condensing coil wound outside the water tank; it also includes a first temperature sensor for detecting the ambient temperature, a second temperature sensor for detecting the water tank temperature and a controller. The first temperature sensor, the second temperature sensor and the controller are connected electrically or by communication. The position of the first temperature sensor is not specifically limited in the present invention, and is only used to collect the ambient temperature of the heat pump system to obtain the ambient temperature T a The second temperature sensor is arranged inside the water tank to obtain the actual heating temperature T r .

[0036] like Figure 1 As shown, a control method for preventing a compressor from frequently shutting down due to over-temperature conditions according to an embodiment of the present invention comprises the following steps:

[0037] S10 obtains the actual heating temperature T at the current moment r and set heating temperature T set The difference ΔT1, according to the temperature difference range where the difference ΔT1 is located, the corresponding operating frequency level F i Determine the starting operating frequency gear F b If the difference ΔT1 is within the set temperature difference range that needs to be corrected, the operating frequency level F corresponding to the temperature difference range is further adjusted. i Perform ambient temperature correction to obtain the starting operating frequency gear F b.

[0038] The temperature difference intervals include a first temperature difference interval, a second temperature difference interval, a third temperature difference interval and a fourth temperature difference interval; wherein the first temperature difference interval is 0°C≤ΔT1<5°C; the second temperature difference interval is 5°C≤ΔT1<10°C; the third temperature difference interval is 10°C≤ΔT1<15°C; the fourth temperature difference interval is ΔT1≥15°C;

[0039] The working frequency level F i The value of i in the formula ranges from 0 to 10, F0 represents the lowest operating frequency, and F 10 Indicates the highest operating frequency gear;

[0040] If ΔT1 is in the first temperature difference range, then its operating frequency level F i is F0; if ΔT1 is in the second temperature difference range, then its operating frequency level is F i If ΔT1 is in the third temperature difference range, its operating frequency level is F i If ΔT1 is in the fourth temperature difference range, its operating frequency level is F i F 10 ;Specific details are shown in Table 1:

[0041]

[0042] Specifically, when the difference ΔT1 is in the first temperature difference zone or the fourth temperature difference zone, the starting working frequency gear F b Equal to the operating frequency level F i , respectively F0 and F 10 When the difference ΔT1 is in the second temperature difference range or the third temperature difference range, the operating frequency gear F i Perform ambient temperature correction to obtain the starting operating frequency gear F b ;

[0043] The ambient temperature correction is to obtain the current ambient temperature T a , according to the ambient temperature T a The temperature range determines the corresponding correction frequency gear value n, and the starting working frequency gear F b F i+n ;

[0044] The temperature interval includes a first temperature interval, a second temperature interval, a third temperature interval and a fourth temperature interval; wherein the first temperature interval is T a <-15℃, the corresponding correction frequency gear value n is 3; the second temperature range is -15℃≤T a <0℃, the corresponding correction frequency gear value n is 2; the third temperature range is 0℃≤T a<15℃, the corresponding correction frequency gear value n is 0; the fourth temperature range is T a ≥15℃, the corresponding correction frequency gear value n is -1; as shown in Table 2:

[0045]

[0046] S20 compressor starts at operating frequency level F b The corresponding working frequency is started, and after the TM cycle timing ends, the actual heating temperature T at the current moment is obtained. r , actual heating temperature T during TM cycle r The change value ΔT r , according to the actual heating temperature T at the current moment r , set heating temperature T set Between the shutdown hysteresis LD and the actual change value ΔT r and the set change value ΔT set The relationship between them is used to make corresponding judgments and executions on the working status of the compressor:

[0047] If the actual heating temperature T r <Set heating temperature T set , and the actual change value ΔT r ≤Setting change value ΔT set When the compressor operating frequency increases by 1 level, it will reach the highest frequency level F. 10 ;

[0048] If the heating temperature is set to T set The sum of the shutdown differential LD ​​≤ the actual heating temperature T r <Set heating temperature T set When the shutdown hysteresis LD is equal to the sum of 2℃, the compressor operating frequency drops by 1 level until it reaches the lowest frequency level F0;

[0049] If the actual heating temperature T r ≥Set heating temperature T set When the shutdown hysteresis difference LD is equal to 2℃, the compressor will be triggered to shutdown due to overtemperature.

[0050] In other cases, the compressor frequency remains unchanged; the actual heating temperature T after the next TM cycle timing ends is continuously obtained. r , and the actual heating temperature T during the TM cycle r The change value ΔT r .

[0051] Specifically, the heating temperature T is set set The specific value depends on the user's needs.

[0052] Specifically, the TM period ranges from 0 to 10 minutes, and is preferably 5 minutes in this embodiment.

[0053] Specifically, the heating temperature T is set in the TM cycle. set The change value ΔT set The value range is 0 to 5°C, and the shutdown hysteresis LD value range is 0 to 10°C. The specific value of each parameter depends on the user's needs and the characteristics of the system.

[0054] Specifically, the compressor frequency upshift, downshift and temperature shutdown will only be judged and executed when the TM cycle timing ends.

[0055] Specifically, when the compressor is defrosted, the control method for preventing the compressor from frequently shutting down due to overtemperature is stopped to adjust the compressor operating frequency. After the defrosting operation is completed, the compressor operating frequency level must be restored to that before defrosting, and the control method for preventing the compressor from frequently shutting down due to overtemperature is started only after the compressor has run for 5 minutes.

[0056] Compared with the prior art, the present invention uses the temperature difference range of the difference ΔT1 and the ambient temperature T a Determine the starting operating frequency gear F b Then the compressor starts at the operating frequency level F b After running the TM cycle, according to the actual heating temperature T at the current moment r , set the frequency reduction temperature T j , Set the shutdown temperature T t and the actual heating temperature T in the TM cycle r The actual change value ΔT r , set the change value ΔT set Based on the relationship between the compressor frequency, the frequency increase, frequency decrease or shutdown judgment can be made to prevent the frequent start and stop of the compressor, which may lead to reduced equipment efficiency, shortened life, decreased stability and other problems.

[0057] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. When the above description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of the present application, for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0058] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A control method for preventing a compressor from frequently shutting down due to over-temperature, characterized in that: Get the actual heating temperature T at the current moment r and set heating temperature T set The difference ΔT1, according to the temperature difference range where the difference ΔT1 is located, the corresponding operating frequency level F i Determine the starting operating frequency gear F b If the difference ΔT1 is within the set temperature difference range that needs to be corrected, the operating frequency level F corresponding to the temperature difference range is further adjusted. i Perform ambient temperature correction to obtain the starting operating frequency gear F b ; The compressor starts at operating frequency level F b The corresponding working frequency is started. After the TM cycle timing ends, according to the actual heating temperature T at the current moment r , set the frequency reduction temperature T j , Set the shutdown temperature T t and the actual heating temperature T in the TM cycle r The actual change value ΔT r , set the change value ΔT set The relationship between the compressor frequency increase, frequency reduction or shutdown is determined: If the actual heating temperature T r Less than the set heating temperature T set , and the actual change value ΔT r ≤Setting change value ΔT set When the compressor starts working at frequency level F b Increase one gear until it reaches the highest frequency gear F 10 ; If the actual heating temperature T r Greater than the set frequency reduction temperature T j , compressor starting operating frequency gear F b Downgrade one gear until it reaches the lowest frequency gear F0; If the actual heating temperature T r Greater than the set shutdown temperature T t , the compressor is triggered to temperature shutdown; The set shutdown temperature T t Greater than the set frequency reduction temperature T j .

2. The control method for preventing the compressor from frequently shutting down due to overtemperature according to claim 1 is characterized in that: The temperature difference interval includes multiple temperature difference intervals. As the temperature difference value included in the temperature difference interval increases, the operating frequency level F of the compressor increases. i Also increased.

3. The control method for preventing the compressor from frequently shutting down due to overtemperature according to claim 2 is characterized in that: The ambient temperature correction is to obtain the current ambient temperature T a , according to the ambient temperature T a The temperature range determines the corresponding correction frequency gear value n, and then starts the working frequency gear F b F i+n .

4. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 3 is characterized in that: The temperature interval includes multiple temperature intervals. As the temperature values ​​included in the temperature intervals increase, the correction frequency level value n also decreases.

5. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 4 is characterized in that: The set frequency reduction temperature T j Set the heating temperature T set The sum of the shutdown hysteresis LD, where the shutdown hysteresis LD ranges from 0 to 10°C, and its specific value depends on the user's needs and system characteristics.

6. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 5, characterized in that: The set shutdown temperature T t Set the heating temperature T set Add 2°C to the sum of the shutdown hysteresis LD, where the shutdown hysteresis LD value range is 0 to 10°C, and its specific value depends on the user's needs and system characteristics.

7. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 6, characterized in that: The temperature difference intervals include a first temperature difference interval, a second temperature difference interval, a third temperature difference interval and a fourth temperature difference interval; wherein the first temperature difference interval is 0°C≤ΔT1<5°C, and its corresponding operating frequency gear F i F0; the second temperature difference range is 5℃≤ΔT1<10℃, and its corresponding working frequency gear is F i The third temperature difference range is 10℃≤ΔT1<15℃, and its corresponding working frequency level is F i The fourth temperature difference range is ΔT1 ≥ 15°C, and its corresponding operating frequency level is F i F 10 .

8. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 7, characterized in that: When the difference ΔT1 is in the first temperature difference range and the fourth temperature difference range, the starting working frequency gear F b Equal to the operating frequency level F i , respectively F0 and F 10 When the difference ΔT1 is in the second temperature difference range or the third temperature difference range, the operating frequency gear F i Perform ambient temperature correction to obtain the starting operating frequency gear F b .

9. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 8, characterized in that: The ambient temperature correction is to obtain the current ambient temperature T a , according to the ambient temperature T a The temperature range determines the corresponding correction frequency gear value n, and the starting working frequency gear F is obtained. b F i+n .

10. The control method for preventing the compressor from frequently shutting down due to over-temperature according to claim 9, characterized in that: The temperature interval includes a first temperature interval, a second temperature interval, a third temperature interval and a fourth temperature interval; wherein the first temperature interval is T a <-15℃, the corresponding correction frequency gear value n is 3; the second temperature range is -15℃≤T a <0℃, the corresponding correction frequency gear value n is 2; the third temperature range is 0℃≤T a <15℃, the corresponding correction frequency gear value n is 0; the fourth temperature range is T a ≥15℃, the corresponding correction frequency gear value n is -1.

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