阅读说明：本技术 一种集控制冷系统的控制方法、装置及集控制冷系统 (Control method and device of centralized control refrigeration system and centralized control refrigeration system ) 是由 么宇 吴波 李福良 关焕豪 张辰 于 2021-06-23 设计创作，主要内容包括：本发明公开一种集控制冷系统的控制方法、装置及集控制冷系统。其中,该方法包括：获取所述集控制冷系统中各个内机的多种运行参数；根据各个内机的多种运行参数识别故障内机,并确定所述故障内机的故障类型。本发明提出一种集控制冷系统的故障检测方案,从而能够及时准确的识别集控制冷系统中的故障内机,并确定故障内机的故障类型,从而保证对故障内机的及时诊断和维修。(The invention discloses a control method and device of a centralized control refrigeration system and the centralized control refrigeration system. Wherein, the method comprises the following steps: acquiring various operation parameters of each internal machine in the centralized control refrigeration system; and identifying the fault internal machine according to various operation parameters of each internal machine, and determining the fault type of the fault internal machine. The invention provides a fault detection scheme of a centralized control refrigeration system, so that a fault internal machine in the centralized control refrigeration system can be timely and accurately identified, the fault type of the fault internal machine is determined, and the timely diagnosis and maintenance of the fault internal machine are ensured.)

1. A method of controlling a centrally controlled refrigerant system, the method comprising:

acquiring various operation parameters of each internal machine in the centralized control refrigeration system;

and identifying the fault internal machine according to various operation parameters of each internal machine, and determining the fault type of the fault internal machine.

2. The method according to claim 1, characterized in that said operating parameters comprise at least:

the cabinet temperature of the inner machine, the inlet temperature and the outlet temperature of the inner machine, the display step number and the actual step number of the electronic expansion valve of the inner machine, and the superheat degree of the inner machine.

3. The method according to claim 2, wherein identifying a malfunctioning internal unit based on a plurality of operating parameters of the respective internal unit and determining a type of fault of the malfunctioning internal unit comprises:

judging whether the cabinet temperature of each internal unit exceeds a first threshold value;

if so, determining that the internal machine is a fault internal machine, and then determining the fault type of the internal machine according to the inlet temperature and the outlet temperature of the fault internal machine and the display steps of the electronic expansion valve of the fault internal machine;

if not, the fault indoor unit is further identified according to the superheat degree of the indoor unit and the display step number of the electronic expansion valve, and the fault type of the fault indoor unit is determined.

4. The method according to claim 3, wherein determining the fault type of the faulty internal machine according to the inlet temperature and the outlet temperature of the faulty internal machine and the display step number of the electronic expansion valve of the faulty internal machine comprises:

if the inlet temperature and the outlet temperature of the fault internal machine simultaneously show a rising trend, and the rising trend accords with a first preset condition, determining whether the fault type of the fault internal machine is stuck of an electronic expansion valve according to the display steps of the electronic expansion valve of the fault internal machine;

and if the inlet temperature and the outlet temperature of the fault internal machine simultaneously show descending trends, and the descending trends meet a second preset condition, determining whether the fault type of the fault internal machine is the internal leakage of the electronic expansion valve according to the display steps of the electronic expansion valve of the fault internal machine.

5. The method of claim 4,

the first preset condition is that the rising amplitude of the inlet temperature and the outlet temperature exceeds a first preset amplitude, and the temperature difference between the outlet temperature and the inlet temperature is reduced;

the second preset condition is that the descending amplitude of the inlet temperature and the outlet temperature exceeds a second preset amplitude.

6. The method according to claim 4, wherein determining whether the failure type of the electronic expansion valve of the failed internal machine is stuck according to the display steps of the electronic expansion valve comprises:

judging whether the display step number of the electronic expansion valve of the fault internal machine is zero or not;

if so, determining the fault type of the internal machine with the fault as the fault of the non-electronic expansion valve;

and if not, determining that the fault type of the internal machine with the fault is stuck of the electronic expansion valve.

7. The method according to claim 4, wherein determining whether the failure type of the electronic expansion valve of the failed internal machine is internal leakage of the electronic expansion valve according to the display step number of the electronic expansion valve comprises:

judging whether the display step number of the electronic expansion valve of the fault internal machine is zero or not;

if so, determining the fault type of the fault internal machine as internal leakage of the electronic expansion valve;

and if not, determining that the fault type of the internal machine with the fault is the fault of the non-electronic expansion valve.

8. The method of claim 3, wherein if not, identifying a malfunctioning indoor unit further based on a superheat of the indoor unit and a number of display steps of the electronic expansion valve, and determining a type of malfunction of the malfunctioning indoor unit comprises:

judging whether the superheat degree of each indoor unit exceeds a second threshold value;

if so, determining the internal machine as a fault internal machine, and then determining the fault type of the internal machine according to the actual step number of the electronic expansion valve of the fault internal machine;

and if not, determining that no fault indoor unit exists in the centralized control refrigeration system.

9. The method of claim 8, wherein determining the type of failure based on the actual number of steps of the electronic expansion valve of the failed internal machine thereafter comprises:

judging whether the actual step number of the electronic expansion valve of the fault indoor unit is greater than or equal to a preset maximum step number or not, and maintaining a preset time length;

if so, determining that the fault type of the fault internal machine is the electronic expansion valve step loss;

and if not, determining that the fault type of the internal machine with the fault is the fault of the non-electronic expansion valve.

10. The method according to any one of claims 1 to 9, wherein after identifying a malfunctioning indoor unit based on a plurality of operating parameters of the respective indoor unit and determining a type of malfunction of the malfunctioning indoor unit, the method further comprises:

determining a normal internal machine without a fault in the centralized control refrigeration system, and acquiring the exhaust temperature of a compressor;

determining whether PID adjusting parameters need to be corrected according to the exhaust temperature of the compressor; and the PID adjusting parameter is used for calculating the opening adjustment quantity of the electronic expansion valve of the normal internal machine.

11. The method of claim 10, wherein determining whether a PID adjustment parameter needs to be modified based on a discharge temperature of the compressor comprises:

judging whether the difference value between the exhaust temperature of the compressor and the preset temperature is in a preset range or not;

if yes, the PID adjusting parameter does not need to be corrected;

and if not, correcting the PID adjusting parameter according to the exhaust temperature of the compressor and the superheat degree of the normal indoor unit.

12. The method as claimed in claim 11, wherein the PID adjustment parameter is corrected according to the discharge temperature of the compressor and the superheat degree of the normal indoor unit by the following formula:

wherein Q is a corrected PID adjustment parameter, T_SuperheatingIs the superheat degree, T, of the normal indoor unit_{Superheat setting}Is a superheat setting value, T_{Exhaust of gases}Is the discharge temperature, T, of the compressor_{Exhaust up}Is a preset maximum value of the exhaust temperature.

13. The method of claim 12, after determining whether a PID tuning parameter needs to be modified based on the discharge temperature of the compressor, the method further comprising:

if the PID adjusting parameter is determined to be corrected, calculating the opening degree adjusting quantity of the electronic expansion valve of the normal indoor unit according to the corrected PID adjusting parameter Q, and realizing the adjustment through the following formula:

Δu_k＝QK_p(e_k-e_k-1)+QK_ie_k+QK_d(e_k-2e_k-1+e_k-2)；

wherein, Δ u_kFor the adjustment of the opening, K_pIs a proportionality coefficient, T_iTo integrate the time constant, T_dIs a differential time constant, T is a sampling period, e_kIs the superheat deviation of the normal inner machine in the kth sampling period, K is a non-zero natural number, K_iIs the integral coefficient, K_dIs a differential coefficient;

and if the PID adjusting parameters are determined not to be required to be corrected, calculating the opening degree adjusting quantity of the electronic expansion valve of the normal indoor unit according to preset PID adjusting parameters.

14. The method of claim 13, further comprising:

and if the calculated opening degree adjustment amount exceeds a preset adjustment amplitude, determining the final opening degree adjustment amount as the preset adjustment amplitude.

15. The method according to any one of claims 1 to 9, wherein after identifying a malfunctioning indoor unit based on a plurality of operating parameters of the respective indoor unit and determining a type of malfunction of the malfunctioning indoor unit, the method further comprises:

and executing corresponding emergency operation according to the fault type of the internal fault machine.

16. The method of claim 15, wherein the fault type includes at least one of: the electronic expansion valve is stuck, the inside of the electronic expansion valve leaks, the electronic expansion valve is out of step, and the non-electronic expansion valve fails;

according to the fault type of the internal fault unit, corresponding emergency operation is executed, and the emergency operation comprises the following steps:

if the fault type of the fault inner machine is that the electronic expansion valve is blocked, triggering the fault inner machine to give an alarm, and controlling an electromagnetic valve on an auxiliary liquid supply pipe of the fault inner machine to be opened so as to use the auxiliary liquid supply pipe to supply liquid;

if the fault type of the fault inner machine is leakage inside the electronic expansion valve, triggering the fault inner machine to give an alarm, and controlling the electromagnetic valve on the main liquid supply pipe of the fault inner machine to be closed;

if the fault type of the fault inner machine is that the electronic expansion valve is out of step, triggering the fault inner machine to give an alarm, and controlling the electronic expansion valve on the main liquid supply pipe of the fault inner machine to reset;

and if the fault type of the fault internal machine is a fault of the non-electronic expansion valve, triggering the fault internal machine to alarm.

17. A control device for a centrally controlled refrigeration system, the device comprising:

the acquisition module is used for acquiring various operation parameters of each internal machine in the centralized control refrigeration system;

and the processing module is used for identifying the fault internal machine according to various operation parameters of each internal machine and determining the fault type of the fault internal machine.

18. A centralized control refrigeration system, which is characterized by comprising a variable frequency condensing unit and a plurality of internal machines, and further comprising a control device of the centralized control refrigeration system according to claim 17.

19. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the method according to any one of claims 1 to 16.

Technical Field

The invention relates to the technical field of refrigeration, in particular to a control method and device of a centralized control refrigeration system and the centralized control refrigeration system.

Background

In the centralized control refrigeration system, when an electronic expansion valve of an internal machine breaks down, the distribution of the refrigerant flow of the internal machine is influenced, so that the system cannot meet the requirements of the internal machine on the cooling capacity under different loads. The main faults of the electronic expansion valve during operation at present include electronic expansion valve step loss, electronic expansion valve internal leakage and electronic expansion valve blocking. Currently, most of the electronic expansion valves are opened by adjusting the opening degree of the electronic expansion valve, and whether the corresponding electronic expansion valve has a fault is judged according to the temperature change condition of the pipeline after adjustment. However, the above-mentioned failure determination scheme has a problem that it is impossible to immediately identify a failed internal machine and determine the failure type thereof in the centralized control refrigeration system.

Aiming at the problem that the fault internal machine cannot be immediately identified and the fault type of the fault internal machine cannot be determined in the existing centralized control refrigeration system, an effective solution is not provided at present.

Disclosure of Invention

The embodiment of the invention provides a control method and device of a centralized control refrigeration system and the centralized control refrigeration system, and aims to solve the problem that a fault internal machine cannot be immediately identified and the fault type of the fault internal machine cannot be determined in the existing centralized control refrigeration system.

In order to solve the technical problem, the invention provides a control method of a centralized control refrigeration system, wherein the method comprises the following steps: acquiring various operation parameters of each internal machine in the centralized control refrigeration system; and identifying the fault internal machine according to various operation parameters of each internal machine, and determining the fault type of the fault internal machine.

Further, the operating parameters include at least: the cabinet temperature of the inner machine, the inlet temperature and the outlet temperature of the inner machine, the display step number and the actual step number of the electronic expansion valve of the inner machine, and the superheat degree of the inner machine.

Further, identifying a faulty internal machine according to various operation parameters of each internal machine, and determining the fault type of the faulty internal machine, including: judging whether the cabinet temperature of each internal unit exceeds a first threshold value; if so, determining that the internal machine is a fault internal machine, and then determining the fault type of the internal machine according to the inlet temperature and the outlet temperature of the fault internal machine and the display steps of the electronic expansion valve of the fault internal machine; if not, the fault indoor unit is further identified according to the superheat degree of the indoor unit and the display step number of the electronic expansion valve, and the fault type of the fault indoor unit is determined.

Further, determining the fault type of the faulty internal machine according to the inlet temperature and the outlet temperature of the faulty internal machine and the display step number of the electronic expansion valve of the faulty internal machine, wherein the method comprises the following steps:

if the inlet temperature and the outlet temperature of the fault internal machine simultaneously show a rising trend, and the rising trend accords with a first preset condition, determining whether the fault type of the fault internal machine is stuck of an electronic expansion valve according to the display steps of the electronic expansion valve of the fault internal machine;

and if the inlet temperature and the outlet temperature of the fault internal machine simultaneously show descending trends, and the descending trends meet a second preset condition, determining whether the fault type of the fault internal machine is the internal leakage of the electronic expansion valve according to the display steps of the electronic expansion valve of the fault internal machine.

Further, the first preset condition is that the rising amplitude of the inlet temperature and the outlet temperature exceeds a first preset amplitude, and the temperature difference between the outlet temperature and the inlet temperature is reduced; the second preset condition is that the descending amplitude of the inlet temperature and the outlet temperature exceeds a second preset amplitude.

Further, determining whether the fault type of the electronic expansion valve of the faulty internal machine is stuck according to the display step number of the electronic expansion valve of the faulty internal machine, including: judging whether the display step number of the electronic expansion valve of the fault internal machine is zero or not; if so, determining the fault type of the internal machine with the fault as the fault of the non-electronic expansion valve; and if not, determining that the fault type of the internal machine with the fault is stuck of the electronic expansion valve.

Further, determining whether the fault type of the electronic expansion valve of the faulty internal machine is internal leakage of the electronic expansion valve according to the display step number of the electronic expansion valve of the faulty internal machine, including: judging whether the display step number of the electronic expansion valve of the fault internal machine is zero or not; if so, determining the fault type of the fault internal machine as internal leakage of the electronic expansion valve; and if not, determining that the fault type of the internal machine with the fault is the fault of the non-electronic expansion valve.

Further, if not, the method further identifies a failed indoor unit according to the superheat degree of the indoor unit and the display step number of the electronic expansion valve, and determines the fault type of the failed indoor unit, and comprises the following steps: judging whether the superheat degree of each indoor unit exceeds a second threshold value; if so, determining the internal machine as a fault internal machine, and then determining the fault type of the internal machine according to the actual step number of the electronic expansion valve of the fault internal machine; and if not, determining that no fault indoor unit exists in the centralized control refrigeration system.

Further, determining the fault type of the faulty internal machine according to the actual step number of the electronic expansion valve of the faulty internal machine, including: judging whether the actual step number of the electronic expansion valve of the fault indoor unit is greater than or equal to a preset maximum step number or not, and maintaining a preset time length; if so, determining that the fault type of the fault internal machine is the electronic expansion valve step loss; and if not, determining that the fault type of the internal machine with the fault is the fault of the non-electronic expansion valve.

Further, after identifying a faulty internal unit according to various operation parameters of each internal unit and determining a fault type of the faulty internal unit, the method further includes: determining a normal internal machine without a fault in the centralized control refrigeration system, and acquiring the exhaust temperature of a compressor; determining whether PID adjusting parameters need to be corrected according to the exhaust temperature of the compressor; and the PID adjusting parameter is used for calculating the opening adjustment quantity of the electronic expansion valve of the normal internal machine.

Further, determining whether a PID adjustment parameter needs to be corrected based on the discharge temperature of the compressor includes: judging whether the difference value between the exhaust temperature of the compressor and the preset temperature is in a preset range or not; if yes, the PID adjusting parameter does not need to be corrected; and if not, correcting the PID adjusting parameter according to the exhaust temperature of the compressor and the superheat degree of the normal indoor unit.

Further, the PID adjusting parameter is corrected according to the exhaust temperature of the compressor and the superheat degree of the normal indoor unit, and the method is realized through the following formula:

wherein Q is a corrected PID adjustment parameter, T_SuperheatingIs the superheat degree, T, of the normal indoor unit_{Superheat setting}Is a superheat setting value, T_{Exhaust of gases}Is the discharge temperature, T, of the compressor_{Exhaust up}Is a preset maximum value of the exhaust temperature.

Further, after determining whether the PID adjustment parameter needs to be corrected according to the discharge temperature of the compressor, the method further includes:

if the PID adjusting parameter is determined to be corrected, calculating the opening degree adjusting quantity of the electronic expansion valve of the normal indoor unit according to the corrected PID adjusting parameter Q, and realizing the adjustment through the following formula:

Δu_k＝QK_p(e_k-e_k-1)+QK_ie_k+QK_d(e_k-2e_k-1+e_k-2)；

wherein, Δ u_kFor the adjustment of the opening, K_pIs a proportionality coefficient, T_iTo integrate the time constant, T_dIs a differential time constant, T is a sampling period, e_kIs the superheat deviation of the normal inner machine in the kth sampling period, K is a non-zero natural number, K_iIs the integral coefficient, K_dIs a differential coefficient;

and if the PID adjusting parameters are determined not to be required to be corrected, calculating the opening degree adjusting quantity of the electronic expansion valve of the normal indoor unit according to preset PID adjusting parameters.

Further, the method further comprises: and if the calculated opening degree adjustment amount exceeds a preset adjustment amplitude, determining the final opening degree adjustment amount as the preset adjustment amplitude.

Further, after identifying a faulty internal unit according to various operation parameters of each internal unit and determining a fault type of the faulty internal unit, the method further includes: and executing corresponding emergency operation according to the fault type of the internal fault machine.

Further, the fault type includes at least one of: the electronic expansion valve is stuck, the inside of the electronic expansion valve leaks, the electronic expansion valve is out of step, and the non-electronic expansion valve fails;

according to the fault type of the internal fault unit, corresponding emergency operation is executed, and the emergency operation comprises the following steps:

if the fault type of the fault inner machine is that the electronic expansion valve is blocked, triggering the fault inner machine to give an alarm, and controlling an electromagnetic valve on an auxiliary liquid supply pipe of the fault inner machine to be opened so as to use the auxiliary liquid supply pipe to supply liquid;

if the fault type of the fault inner machine is leakage inside the electronic expansion valve, triggering the fault inner machine to give an alarm, and controlling the electromagnetic valve on the main liquid supply pipe of the fault inner machine to be closed;

if the fault type of the fault inner machine is that the electronic expansion valve is out of step, triggering the fault inner machine to give an alarm, and controlling the electronic expansion valve on the main liquid supply pipe of the fault inner machine to reset;

and if the fault type of the fault internal machine is a fault of the non-electronic expansion valve, triggering the fault internal machine to alarm.

The invention also provides a control device of the centralized control refrigeration system, wherein the device comprises: the acquisition module is used for acquiring various operation parameters of each internal machine in the centralized control refrigeration system; and the processing module is used for identifying the fault internal machine according to various operation parameters of each internal machine and determining the fault type of the fault internal machine.

The invention also provides a centralized control refrigeration system, wherein the centralized control refrigeration system comprises a variable frequency condensing unit, a plurality of internal machines and a control device of the centralized control refrigeration system.

The invention also provides a computer-readable storage medium, on which a computer program is stored, wherein the program, when executed by a processor, implements the method as described above.

The invention provides a fault detection scheme and an electronic expansion valve feedback regulation scheme of a centralized control refrigeration system, so that a fault internal machine in the centralized control refrigeration system can be timely and accurately identified, and the fault type of the fault internal machine can be determined. The problem that PID adjusting parameters are fixed and unchanged is solved, the opening of the electronic expansion valve is adjusted to adapt to changes of different operation conditions, the adjustment of the opening is more accurate, and the energy efficiency ratio of the centralized control refrigeration system is more optimized.

Drawings

FIG. 1 is a flow chart of a method of controlling a centrally controlled refrigeration system according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a centrally controlled display case according to an embodiment of the present invention;

FIG. 3 is a flow chart of fault identification and electronic expansion valve feedback adjustment for a centrally controlled display case in accordance with an embodiment of the present invention;

FIG. 4 is a flow chart of the overall control of a centrally controlled refrigeration system according to an embodiment of the present invention;

fig. 5 is a block diagram of a control apparatus for a centrally controlled refrigeration system according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, and "a plurality" typically includes at least two unless the context clearly indicates otherwise.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of additional like elements in the article or device comprising the element.

Alternative embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Example 1

Fig. 1 is a flowchart of a control method of a centrally controlled refrigeration system according to an embodiment of the present invention, as shown in fig. 1, the method including the steps of:

s101, acquiring various operation parameters of each internal machine in the centralized control refrigeration system; the above-mentioned operational parameters at least include: the cabinet temperature of the inner machine, the inlet temperature and the outlet temperature of the inner machine, the display step number and the actual step number of the electronic expansion valve of the inner machine, and the superheat degree of the inner machine.

And S102, identifying the fault indoor unit according to various operation parameters of each indoor unit, and determining the fault type of the fault indoor unit.

The embodiment provides a fault detection scheme of a centralized control refrigeration system, so that a fault internal machine in the centralized control refrigeration system can be timely and accurately identified, the fault type of the fault internal machine is determined, and the timely diagnosis and maintenance of the fault internal machine are guaranteed.

In the step S102, a failed indoor unit is first identified according to the cabinet temperature of the indoor unit, and if the cabinet temperature of the indoor unit is not abnormal, the failed indoor unit is further identified according to the superheat degree of the indoor unit. In particular, this can be achieved by the following preferred embodiments:

1) and judging whether the cabinet temperature of each internal unit exceeds a first threshold value.

2) And if the cabinet temperature of the internal machine exceeds a first threshold value, determining that the internal machine is a fault internal machine, and then determining the fault type of the internal machine according to the inlet temperature and the outlet temperature of the fault internal machine and the display step number of an electronic expansion valve of the fault internal machine.

21) If the inlet temperature and the outlet temperature of the fault indoor unit simultaneously show a rising trend, and the rising trend accords with a first preset condition: and determining whether the fault type is the electronic expansion valve jamming according to the display steps of the electronic expansion valve of the fault indoor unit if the rising amplitude of the inlet temperature and the outlet temperature exceeds a first preset amplitude and the temperature difference between the outlet temperature and the inlet temperature is reduced.

Specifically, whether the display step number of an electronic expansion valve of a faulted internal machine is zero or not is judged; if so, determining the fault type of the internal machine with the fault as the fault of the non-electronic expansion valve; and if not, determining that the fault type of the internal machine with the fault is stuck of the electronic expansion valve.

Based on the preferred embodiment, after the fault internal machine is identified in time, the fault type of the fault internal machine is also determined in time, and if the fault type is determined to be blocked by the electronic expansion valve, corresponding emergency operation is executed: and triggering the fault inner machine to alarm, and controlling the opening of an electromagnetic valve on an auxiliary liquid supply pipe of the fault inner machine so as to use the auxiliary liquid supply pipe to supply liquid and prevent the cabinet from overtemperature. It should be noted that the internal fault alarm may be triggered when an internal fault is identified, or may be triggered after the fault type is determined, and the specific triggering time may be set according to actual requirements.

22) If the inlet temperature and the outlet temperature of the fault internal machine simultaneously show descending trend, and the descending trend accords with a second preset condition: and if the descending amplitude of the inlet temperature and the outlet temperature exceeds a second preset amplitude, determining whether the fault type is internal leakage of the electronic expansion valve according to the display steps of the electronic expansion valve of the fault internal machine.

Specifically, whether the display step number of an electronic expansion valve of a faulted internal machine is zero or not is judged; if so, determining the fault type of the internal fault machine as internal leakage of the electronic expansion valve; and if not, determining that the fault type of the internal machine with the fault is the fault of the non-electronic expansion valve.

Based on the preferred embodiment, after the fault internal machine is identified in time, the fault type of the fault internal machine is also determined in time, and if the fault type is determined to be internal leakage of the electronic expansion valve, corresponding emergency operation is executed: and triggering the fault inner machine to alarm, and controlling the electromagnetic valve on the main liquid supply pipe of the fault inner machine to be closed to prevent the cabinet temperature from being ultralow in temperature. It should be noted that the internal fault alarm may be triggered when an internal fault is identified, or may be triggered after the fault type is determined, and the specific triggering time may be set according to actual requirements.

3) And if the cabinet temperature of the internal machine does not exceed the first threshold value, identifying the failed internal machine further according to the superheat degree of the internal machine and the display step number of the electronic expansion valve, and determining the failure type of the failed internal machine.

Specifically, it is determined whether the degree of superheat of each of the indoor units exceeds the second threshold value.

And if the superheat degree of the indoor unit exceeds a second threshold value, determining the indoor unit as a fault indoor unit, and then determining the fault type of the indoor unit according to the actual step number of the electronic expansion valve of the fault indoor unit. Specifically, the method comprises the following steps: judging whether the actual step number of an electronic expansion valve of the fault indoor unit is greater than or equal to a preset maximum step number or not, and maintaining a preset time length; if so, determining the fault type of the fault internal machine as the electronic expansion valve step-out; and if not, determining that the fault type of the internal machine with the fault is the fault of the non-electronic expansion valve.

Based on the preferred embodiment, after the fault internal machine is identified in time, the fault type of the fault internal machine is also determined in time, and if the fault type is determined to be the electronic expansion valve step-out, corresponding emergency operation is executed: and triggering the fault inner machine to alarm, and controlling the electronic expansion valve on the main liquid supply pipe of the fault inner machine to reset. It should be noted that the internal fault alarm may be triggered when an internal fault is identified, or may be triggered after the fault type is determined, and the specific triggering time may be set according to actual requirements.

And if the superheat degrees of all the indoor units do not exceed the second threshold value, determining that no fault indoor unit exists in the centralized control refrigeration system.

It should be noted that the fault type in this embodiment includes at least one of the following: the electronic expansion valve is stuck, the inside of the electronic expansion valve leaks, the electronic expansion valve is out of step, and the non-electronic expansion valve has faults. The emergency operation corresponding to the first three fault types is described, and if the non-electronic expansion valve is in fault, the alarm of the fault internal machine is directly triggered.

4) An electronic expansion valve as a throttling part is one of core parts of a refrigeration apparatus (such as a showcase). In the prior PID regulation control of the display cabinet, PID regulation parameters are fixed, so that the regulation of the opening of the electronic expansion valve cannot adapt to the change of different operation conditions, the regulation of the opening is not accurate enough, and the ideal energy efficiency ratio of a refrigerant circulating system of the centralized control display cabinet is difficult to achieve.

Based on this, the present embodiment provides a feedback adjustment scheme for an electronic expansion valve, which adjusts a control strategy according to the feedback condition of a single display cabinet to determine whether a system PID adjustment parameter is needed.

Specifically, after the faulty internal machine is identified according to various operation parameters of each internal machine and the fault type of the faulty internal machine is determined, for the normal internal machine without fault in the centralized control refrigeration system, whether the PID adjusting parameter needs to be corrected or not can be determined according to the exhaust temperature of the compressor, so that the opening degree adjusting quantity of the electronic expansion valve is further calculated according to the PID adjusting parameter.

Specifically, the exhaust temperature of the compressor is acquired; determining whether PID adjusting parameters need to be corrected according to the exhaust temperature of the compressor; and the PID adjusting parameters are used for calculating the opening adjustment quantity of the electronic expansion valve of the normal internal machine.

As to how to determine whether the PID adjustment parameter needs to be corrected, this embodiment provides a preferable implementation manner of determining whether the difference between the discharge temperature of the compressor and the preset temperature is within a preset range. If so, the PID tuning parameters do not need to be modified. If not, correcting PID adjusting parameters according to the exhaust temperature of the compressor and the superheat degree of the normal indoor unit, and specifically realizing the following formula:

wherein Q is a corrected PID adjustment parameter, T_SuperheatingThe superheat degree of the normal inner machine, T_{Superheat setting}Is a superheat setting value, T_{Exhaust of gases}Is the discharge temperature, T, of the compressor_{Exhaust up}Is a preset maximum value of the exhaust temperature.

After the PID adjusting parameter is corrected, the opening degree adjusting quantity of the electronic expansion valve of the normal internal machine is calculated according to the corrected PID adjusting parameter Q, and the method is realized by the following formula:

Δu_k＝QK_p(e_k-e_k-1)+QK_ie_k+QK_d(e_k-2e_k-1+e_k-2)；

wherein, Δ u_kFor the adjustment of the opening, K_pIs a proportionality coefficient, T_iTo integrate the time constant, T_dIs a differential time constant, T is a sampling period, e_kIs the superheat deviation of the normal inner machine in the kth sampling period, K is a non-zero natural number, K_iIs the integral coefficient, K_dIs a differential coefficient;

and if the PID adjusting parameters are determined not to be required to be corrected, calculating the opening degree adjusting quantity of the electronic expansion valve of the normal indoor unit according to the preset PID adjusting parameters.

In order to ensure that the opening degree of the electronic expansion valve is adjusted within a proper range, the embodiment also sets an opening degree maximum limit value and an opening degree minimum limit value in advance, if the finally determined opening degree of the electronic expansion valve exceeds the opening degree maximum limit value, the electronic expansion valve is controlled to operate according to the opening degree maximum limit value, and if the finally determined opening degree of the electronic expansion valve is lower than the opening degree minimum limit value, the electronic expansion valve is controlled to operate according to the opening degree minimum limit value. Therefore, the situation that the opening degree of the electronic expansion valve is too high or too low is avoided, and the normal and stable operation of the system is ensured.

Besides setting the maximum opening value and the minimum opening value, the present embodiment may also set a preset adjustment range, and if the calculated opening adjustment amount exceeds the preset adjustment range, determine that the final opening adjustment amount is the preset adjustment range. Therefore, the opening degree of the electronic expansion valve is adjusted within a reasonable range, and the condition that the opening degree of the electronic expansion valve is too high or too low is avoided, so that the normal and stable operation of the system is ensured.

Example 2

The centralized control refrigeration system can be a centralized control display cabinet, namely an internal machine in the centralized control refrigeration system is a display cabinet. Of course, the internal unit may be other refrigeration equipment such as an air conditioner. The present embodiment takes a showcase as an example, and details a control scheme of the centralized control refrigeration system of the present application are described with reference to the accompanying drawings.

Fig. 2 is a schematic structural diagram of a centralized control display cabinet according to an embodiment of the present invention, as shown in fig. 2, a plurality of display cabinets are connected to a variable frequency condenser unit through a return air pipe (dashed line in fig. 2), and the variable frequency condenser unit is connected to the plurality of display cabinets through a communication line (dashed line in fig. 2), so as to achieve information interaction. A main liquid supply pipe is led out from the variable-frequency condensing unit, a plurality of branches are led out from the main liquid supply pipe and are respectively connected to each display cabinet, namely a main liquid supply pipe of each display cabinet, and an electronic expansion valve and an electromagnetic valve are arranged on the main liquid supply pipe. In addition, an auxiliary liquid supply pipe is provided between the showcase 1 and the showcase 2, and an auxiliary liquid supply pipe is provided between the showcase 3 and the showcase 4, and so on. The auxiliary liquid supply pipe is provided with an electromagnetic valve, and the opening and closing of the electromagnetic valve determine the on-off of the auxiliary liquid supply pipe. And when the fault type of the fault internal machine is that the electronic expansion valve is stuck, controlling the electromagnetic valve on the auxiliary liquid supply pipe of the fault internal machine to open so as to use the auxiliary liquid supply pipe to supply liquid.

Fig. 3 is a flow chart of fault identification and electronic expansion valve feedback adjustment of the centrally controlled showcase according to an embodiment of the present invention, as shown in fig. 3, the flow chart includes the following steps:

and S301, acquiring the operation parameters of the internal machine. It should be noted that the operation parameters of the internal machine obtained in this step may be operation parameters that need to be determined in the following step: the cabinet temperature of the inner machine can also be all the operation parameters of the inner machine required by the whole control flow: the cabinet temperature of the inner machine, the inlet temperature and the outlet temperature of the inner machine, the display step number and the actual step number of the electronic expansion valve of the inner machine, and the superheat degree of the inner machine. In this embodiment, this step is described by taking the cabinet temperature of the internal machine as an example.

Step S302, judging whether the cabinet temperature of the internal machine exceeds a first threshold value; if so, step S303 is performed, otherwise, step S313 is performed.

The first threshold value is a critical value of the cabinet temperature of the inner unit, and can be set according to actual requirements, and if the cabinet temperature of the inner unit exceeds the critical value, the cabinet temperature of the inner unit is indicated to be abnormal, and the inner unit breaks down. Cabinet temperature T of inner machine_{In the cabinet}Is the real-time temperature T detected by a cabinet temperature sensor (generally arranged at an air return inlet)_{Sensor with a sensor element}And T_{Cabinet temperature correction}(preset value for correcting the cabinet temperature) or a difference. I.e. T_{In the cabinet}＝T_{Sensor with a sensor element}±T_{Cabinet temperature correction}。

Step S303, after the cabinet temperature of the internal machine is judged to exceed the first threshold value, the internal machine is determined to be a fault internal machine, and the inlet temperature and the outlet temperature of the fault internal machine are obtained. The inlet temperature of the malfunctioning internal machine is the inlet temperature of the evaporator, and the outlet temperature of the malfunctioning internal machine is the outlet temperature of the evaporator.

And step S304, judging the variation trend of the inlet temperature and the outlet temperature.

If the variation trends of the inlet temperature and the outlet temperature are rising trends, the rising amplitudes of the inlet temperature and the outlet temperature exceed a first preset amplitude, and the temperature difference between the outlet temperature and the inlet temperature is reduced, executing step S305;

if the variation trends of the inlet temperature and the outlet temperature are both decreasing trends and the decreasing magnitudes of the inlet temperature and the outlet temperature both exceed the second preset magnitude, step S309 is performed.

In step S305, the display step number of the electronic expansion valve of the malfunctioning internal unit is obtained.

Step S306, determining whether the display step number is 0, if yes, executing step S308, otherwise executing step S307.

Step S307, determining the fault type of the faulty internal unit as: the electronic expansion valve is blocked, the fault inner machine gives an alarm, and the fault inner machine uses the auxiliary liquid supply pipe to supply liquid, so that the overtemperature of the cabinet is prevented.

Step S308, determining that the faulted internal machine is a failure of the non-electronic expansion valve, namely the failure of the internal machine is not caused by the failure of the electronic expansion valve, and alarming by the faulted internal machine.

In the above steps S305 to S308, when the variation trends of the inlet temperature and the outlet temperature of the faulty internal machine are both increasing trends, the specific fault type (electronic expansion valve stuck, non-electronic expansion valve fault) is determined by combining the display steps of the electronic expansion valve.

For example, after detecting that the cabinet temperature exceeds a first threshold (e.g., 19 ℃), the inlet temperature and the outlet temperature of the faulty internal machine increase simultaneously, both of the increasing magnitudes exceed a first preset magnitude (e.g., 3 ℃), in general, the lower the ambient temperature, the lower the value of the first preset magnitude), and the temperature difference Δ T between the outlet temperature and the inlet temperature decreases. And if the display step number of the electronic expansion valve is further judged not to be 0, determining that the fault type of the fault internal machine is that the electronic expansion valve is stuck at 0 step. Emergency operations may be performed at this time: the fault inner machine reports the high temperature of E01 to alarm, controls the electromagnetic valve on the auxiliary liquid supply pipe of the fault inner machine to open, and the fault inner machine uses the auxiliary liquid supply pipe to supply liquid, thereby preventing the cabinet temperature from generating ultrahigh temperature.

Step S309, the display step number of the electronic expansion valve of the malfunctioning internal machine is acquired.

Step S310, judging whether the display step number is 0, if so, executing step S312, otherwise, executing step S311.

And step S311, the non-electronic expansion valve is in failure, and the failed internal machine gives an alarm.

Step S312, determining the fault type of the faulty internal unit as: inside revealing of electronic expansion valve, the trouble indoor unit reports to the police, and the solenoid valve on the main feed pipe of trouble indoor unit closes, prevents that the cabinet temperature is ultra-low temperature.

In the above steps S309 to S312, when the variation trends of the inlet temperature and the outlet temperature of the faulty internal machine are both downward trends, the specific fault type (internal leakage of the electronic expansion valve, fault of the non-electronic expansion valve) is determined by combining the display steps of the electronic expansion valve.

For example, after it is detected that the cabinet temperature exceeds a first threshold (e.g., 19 ℃), the inlet temperature and the outlet temperature of the faulty internal machine decrease simultaneously, and both the decreasing amplitudes exceed a second preset amplitude (e.g., 3 ℃), in general, the lower the ambient temperature is, the lower the value of the first preset amplitude is). And if the display step number of the electronic expansion valve is further judged to be 0, determining that the fault type of the fault internal machine is internal leakage of the electronic expansion valve. Emergency operations may be performed at this time: the warning of trouble inner unit, the solenoid valve on the main feed pipe of trouble inner unit closes, prevents that the ultra-low temperature from appearing in the cabinet temperature.

And step 313, if the cabinet temperature of the indoor unit does not exceed the first threshold, acquiring the superheat degree of the indoor unit. If the degree of superheat of the indoor unit has been acquired in the above-described step S301, it is not necessary to repeatedly perform this step.

In step S314, it is determined whether the degree of superheat of the indoor unit exceeds a second threshold (i.e., a maximum limit value of the degree of superheat, e.g., 5 ℃), and if so, step S315 is executed, otherwise, step S319 is executed.

And step S315, acquiring the actual step number of the electronic expansion valve of the failed internal machine.

Step S316, determining whether the actual number of steps of the electronic expansion valve is greater than or equal to the preset maximum number of steps, and maintaining the preset duration. If so, step S317 is performed, otherwise, step S318 is performed.

Step S317, determining the fault type of the faulty internal unit as: the electronic expansion valve is out of step, the throttle cannot be correctly throttled, and the failure internal machine gives an alarm.

And step S318, the non-electronic expansion valve is in failure, and the failed internal machine gives an alarm.

In the above steps S313 to S318, when the cabinet temperature of the internal unit does not exceed the first threshold, the faulty internal unit is further identified according to the degree of superheat of the internal unit, and the specific fault type (electronic expansion valve step loss, non-electronic expansion valve fault) is further determined according to the actual step number of the electronic expansion valve of the faulty internal unit.

The electronic expansion valve can set the maximum step number and the minimum step number, and different adjusting ranges (for example, 0-500 steps) can be set according to the structure and the performance of the electronic expansion valve. When the superheat degree is increased, the number of steps of the electronic expansion valve is increased, so that the flow rate of the refrigerant is increased. When the superheat degree T of the indoor unit is detected_SuperheatingAnd if the actual step number of the electronic expansion valve is greater than or equal to the preset maximum step number and the duration is greater than the preset duration (for example, 60s) when the actual step number exceeds the second threshold (for example, 5 ℃), determining that the fault type of the fault internal machine is that the electronic expansion valve is out of step and cannot correctly throttle, and alarming the fault internal machine at the moment and resetting the electronic expansion valve on the main liquid supply pipe of the fault internal machine.

Note that T is_Superheating(degree of superheat) ═ T_{An outlet}－[T_{An inlet}+T_{Inlet correction}]. Wherein, T_{An outlet}Is the outlet temperature of the internal machine, i.e. the temperature value, T, of the thermal bulb arranged at the outlet of the evaporator_{An inlet}Is the inlet temperature of the internal machine, i.e. the temperature value, T, of the thermal bulb arranged at the inlet of the evaporator_{Inlet correction}Is a correction value for the inlet temperature.

In step S319, the discharge temperature of the compressor is acquired.

And step 320, judging whether the difference value between the exhaust temperature of the compressor and the preset temperature is in a preset range, if so, executing step 321, otherwise, executing step 323.

In step S321, the degree of superheat of the indoor unit is acquired.

And step S322, correcting PID adjusting parameters according to the exhaust temperature of the compressor and the superheat degree of the indoor unit. And the corrected PID adjusting parameter is used for calculating the opening adjustment quantity of the electronic expansion valve of the internal machine. After that, the process may return to step S302 to perform failure determination on the next internal unit.

Step S323, the opening degree of the electronic expansion valve is adjusted according to the preset PID adjustment parameter, and specifically, the opening degree adjustment amount of the electronic expansion valve may be calculated according to the preset PID adjustment parameter.

In the above step S319 to step S323, when the cabinet temperature of the internal machine does not exceed the first threshold and the superheat degree of the internal machine does not exceed the second threshold, it is determined that the internal machine has no fault, and it is further determined whether the PID adjustment parameter needs to be corrected according to the exhaust temperature of the compressor of the external machine, and if so, the opening adjustment amount of the electronic expansion valve is calculated according to the corrected PID adjustment parameter. And if not, calculating the opening adjustment quantity of the electronic expansion valve according to the preset PID adjusting parameter.

Wherein Q is a corrected PID adjustment parameter, T_SuperheatingIs the superheat degree, T, of the normal indoor unit_{Superheat setting}Is a superheat setting value, T_{Exhaust of gases}Is the discharge temperature, T, of the compressor_{Exhaust up}Is a preset maximum value of the exhaust temperature.

Data sampling is carried out on the internal machine for a plurality of periods, and the opening degree variable quantity delta u of the electronic expansion valve of the internal machine is controlled in the kth sampling period_kIs (unit:%):

e_k＝T_superheating-T_{Overheating target}；T_{Overheating target}The superheat degree is a preset target superheat degree;

wherein Kp is a proportionality coefficient, T_iTo integrate the time constant, T_dIs a differential time constant, T is a sampling period (referred to as a time period), e_kIs the superheat deviation at the kth sampling period, K_iIs the integral coefficient, K_dK is a non-zero natural number.

Finally determined opening degree of the electronic expansion valve is equal to current opening degree + delta u_k，Δu_kEither positive or negative, i.e. the opening degree of the electronic expansion valve may be adjusted up or down.

When the opening degree of the electronic expansion valve is adjusted, an opening degree maximum limit value and an opening degree minimum limit value may be set, and if the finally determined opening degree of the electronic expansion valve exceeds the opening degree maximum limit value, the electronic expansion valve is controlled to operate according to the opening degree maximum limit value, and if the finally determined opening degree of the electronic expansion valve is lower than the opening degree minimum limit value, the electronic expansion valve is controlled to operate according to the opening degree minimum limit value. Therefore, the situation that the opening degree of the electronic expansion valve is too high or too low is avoided, and the normal and stable operation of the system is ensured.

Besides the maximum opening value and the minimum opening value, a preset adjustment range can be set, and if the calculated opening adjustment amount exceeds the preset adjustment range, the final opening adjustment amount is determined to be the preset adjustment range. Therefore, the opening degree of the electronic expansion valve is adjusted within a reasonable range, and the condition that the opening degree of the electronic expansion valve is too high or too low is avoided, so that the normal and stable operation of the system is ensured.

Example 3

With reference to fig. 3, the overall control logic of the centralized control refrigeration system is described below, and fig. 4 is a flowchart of the overall control of the centralized control refrigeration system according to the embodiment of the present invention, as shown in fig. 4, the flowchart includes the following steps:

and step S401, obtaining the operating parameters of the internal machine.

And step S402, judging whether the operation parameters meet the fault judgment conditions or not, and obtaining a judgment result. The fault determination condition is a determination condition of each operation parameter, such as whether the cabinet temperature of the indoor unit exceeds a first threshold, whether the superheat degree of the indoor unit exceeds a second threshold, and the like.

And step S403, judging whether the operation parameters accord with PID correction judgment conditions or not, and obtaining a judgment result. The PID correction determination condition is whether a difference between the discharge temperature of the compressor and a preset temperature is within a preset range.

In step S404, the system operates according to the determination result. That is, the determination results of "yes" and "no" after each determination condition in fig. 3 described above.

The embodiment solves the following technical problems:

1) when the centralized control display cabinet is in use, the failure of the electronic expansion valve cannot be detected;

2) the cold quantity of each display cabinet in the centralized control display cabinet is not matched with the requirement;

3) in the existing PID regulation control, PID regulation parameters are fixed, so that the regulation of the opening of the electronic expansion valve cannot adapt to the change of different operation conditions, the opening regulation is not accurate enough, and the ideal energy efficiency ratio of the refrigerant circulating system of the centralized control display cabinet is difficult to achieve.

The embodiment achieves the following technical effects:

1) timely positioning a fault internal machine and determining the fault type;

2) and according to the actual running condition of the compressor, the PID adjusting parameters are corrected in real time, the opening of the electronic expansion valve is accurately adjusted, and the cold quantity and the requirement of each display cabinet are matched.

Example 4

Corresponding to the control method of the centralized control refrigeration system introduced in fig. 1, the present embodiment provides a control device of the centralized control refrigeration system, such as the structural block diagram of the control device of the centralized control refrigeration system shown in fig. 5, and the device includes:

the acquisition module is used for acquiring various operation parameters of each internal machine in the centralized control refrigeration system;

and the processing module is used for identifying the fault internal machine according to various operation parameters of each internal machine and determining the fault type of the fault internal machine.

For the specific technical solutions of the obtaining module and the processing module, the foregoing embodiments have been described in detail, and are not described herein again.

The embodiment also provides a centralized control refrigeration system, which comprises a variable frequency condensing unit, a plurality of internal machines and a control device of the centralized control refrigeration system introduced above.

Example 5

The embodiment of the present invention provides software for implementing the technical solutions described in the above embodiments and preferred embodiments.

Embodiments of the present invention provide a non-volatile computer storage medium, where a computer-executable instruction is stored in the computer storage medium, and the computer-executable instruction may execute a control method of a centralized control refrigeration system in any of the above method embodiments.

The storage medium stores the software, and the storage medium includes but is not limited to: optical disks, floppy disks, hard disks, erasable memory, etc.

The product can execute the method provided by the embodiment of the invention, and has corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the method provided by the embodiment of the present invention.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.