A defrosting control method and system for a condensing unit and a condensing unit

Abstract

The application discloses a defrosting control method and system of a condensing unit and the condensing unit. The method detects the inlet pipe temperature and the outlet pipe temperature of the indoor evaporator at the current time, detects whether the four-way valve reversing fails, controls the working states of the outdoor unit load and the indoor unit load of the condensing unit after determining that the four-way valve reversing fails, and until the condensing unit successfully enters or exits the defrosting mode. Compared with the prior art, the closed-loop detection of the four-way valve reversing failure is realized, and necessary control measures can be taken to ensure that the condensing unit successfully enters the defrosting mode or ends the defrosting mode after the four-way valve reversing failure, so that the stability and reliability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology, specifically to a defrosting control method, system, and condensing unit for a condensing unit. Background Technology

[0002] Currently, the main defrosting method for condensing units used in cold storage is electric heating. This method is prone to problems such as high temperature rebound in the storage area, long defrosting time, low efficiency, and high power consumption due to large defrosting increments. Some products utilize hot gas defrosting solutions, employing a four-way valve to switch the refrigerant flow direction to achieve reverse circulation defrosting. However, condensing units generally use low-temperature refrigerants. When the ambient temperature is low, the pressure difference between the condensing and evaporating pressures of the unit system is very low. At the same time, after the condensing unit stops, the pressure difference between the suction and discharge pressures rapidly decreases to near zero, which can easily cause the four-way valve to fail to switch direction. This can result in the condensing unit waiting to be defrosted failing to enter defrosting mode, or the condensing unit that has finished defrosting not having a defrosting end mode, affecting the normal operation of the condensing unit.

[0003] The related technology discloses a method that compares the pressure difference between the exhaust pressure and the intake pressure with a target value to determine whether the four-way valve switches. If the condition is met, the four-way valve switches; if not, the operating state of the component currently performing condensation is adjusted to ultimately achieve the switching. While this technology overcomes the problem of four-way valve switching failure, which can prevent condensing units awaiting defrosting from entering defrosting mode, or prevent defrosting units from entering a defrosting end mode, thus affecting normal operation, the method fails to achieve closed-loop detection of successful switching because the four-way valve is an open-loop control component. This means it cannot completely solve the practical problem of switching failure, ultimately leading to ice blockage and system malfunctions due to the condensing unit's inability to truly enter defrosting mode; or, if switching fails when exiting defrosting, continued heating causes a rapid rise in storage temperature, damaging stored items and resulting in significant economic losses. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a defrosting control method, system and condensing unit for condensing units, so as to solve the problem in the related technology that the failure of the four-way valve to switch direction causes the condensing unit to be defrosted to be unable to enter the defrosting mode, or the condensing unit that has finished defrosting has no end defrosting mode, which affects the normal use of the condensing unit.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] According to a first aspect of the present invention, a defrosting control method for a condensing unit is provided, comprising:

[0007] Detect the operating mode of the condensing unit;

[0008] If the current working mode is cooling mode or defrosting mode, detect the current inlet pipe temperature of the indoor evaporator and the current outlet pipe temperature of the indoor evaporator.

[0009] Based on the inlet and outlet pipe temperatures, determine whether the four-way valve of the condensing unit has failed to switch direction at the current moment. If the four-way valve fails to switch direction, control the working status of the outdoor unit load and indoor unit load of the condensing unit until the condensing unit successfully enters or exits the defrosting mode.

[0010] Preferably, determining whether the four-way valve of the condensing unit has failed to switch direction at the current moment based on the inlet pipe temperature and the outlet pipe temperature includes:

[0011] If the current working mode is cooling mode, and the difference between the outlet pipe temperature and the inlet pipe temperature is greater than a first preset value, then the four-way valve is determined to have failed to switch.

[0012] If the current working mode is defrosting mode, and the difference between the inlet pipe temperature and the outlet pipe temperature is greater than the second preset value, then the four-way valve is determined to have failed to switch.

[0013] Preferably, when the four-way valve fails to switch, controlling the operating status of the outdoor unit load and indoor unit load of the condensing unit includes:

[0014] If the current working mode is cooling mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is stopped and reset, the indoor fan in the indoor unit load continues to run, and the number of four-way valve switching failures is accumulated.

[0015] After the first preset time, obtain the ambient temperature inside the condenser unit where the indoor unit is located.

[0016] If the ambient temperature inside the warehouse is lower than the preset warehouse temperature alarm temperature, and the number of times the four-way valve switches is less than the first preset number, the internal fan is controlled to keep running, and the compressor, external fan and electronic expansion valve in the external unit load are started.

[0017] After the intake and exhaust pressure difference at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to enter the defrosting mode.

[0018] In defrost mode, when the pressure difference between the suction and discharge at both ends of the piston in the four-way valve reaches the reversing pressure difference again, the four-way valve is de-energized, exiting defrost mode and returning to refrigeration mode.

[0019] Preferably, the method further includes:

[0020] If the current operating mode is cooling mode, and the four-way valve fails to switch, the four-way valve switching failure fault information is defined as a Level 1 manufacturer-level fault and simultaneously reported to the manufacturer; and / or,

[0021] If the current operating mode is refrigeration mode, and the ambient temperature inside the refrigeration unit is greater than or equal to the preset refrigeration temperature alarm temperature, the four-way valve reversal failure fault information is defined as a first-level user-level fault, the condensing unit is controlled to stop running, and the user is simultaneously reminded to perform maintenance or report a repair.

[0022] Preferably, when determining that the four-way valve has failed to switch, controlling the operating state of the outdoor unit load and indoor unit load of the condensing unit further includes:

[0023] If the current working mode is defrosting mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is controlled to stop and reset, while the indoor fan in the indoor unit load continues to run;

[0024] After the second preset time period, the internal fan is kept running, and the compressor, external fan and electronic expansion valve in the external unit load are started;

[0025] After the pressure difference between the intake and exhaust at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to exit the defrosting mode.

[0026] Preferably, the method further includes:

[0027] If the current working mode is defrosting mode, and the four-way valve fails to switch, the number of four-way valve switching failures is accumulated, and the four-way valve switching failure information is defined as a secondary manufacturer-level fault and reported to the manufacturer simultaneously.

[0028] Preferably, the method further includes:

[0029] Start timing from the end of the four-way valve switching and calculate the switching time from the end of the four-way valve switching to the current time;

[0030] If the switching time exceeds the threshold range, the current four-way valve switching failure is determined to be an intermittent failure, and the accumulated number of four-way valve switching failures is cleared to zero.

[0031] Preferably, the method further includes:

[0032] When the condensing chiller unit is powered on for the first time, the timer starts from the moment the compressor starts.

[0033] Preferably, the operating mode of the condenser unit is as follows:

[0034] When the condensing unit starts, if the reversing time is longer than the preset reversing time of the four-way valve, the working mode of the condensing unit is detected.

[0035] According to a second aspect of the present invention, a defrosting control system for a condensing unit is provided, comprising:

[0036] The first detection module is used to detect the operating mode of the condensing unit;

[0037] The second detection module is used to detect the inlet pipe temperature and the outlet pipe temperature of the indoor evaporator at the current moment if the current working mode is cooling mode or defrosting mode.

[0038] The control module is used to determine whether the four-way valve of the condensing unit has failed to switch direction at the current moment based on the inlet pipe temperature and the outlet pipe temperature, and when the four-way valve is determined to have failed to switch direction, it controls the working state of the outdoor unit load and the indoor unit load of the condensing unit until the condensing unit successfully enters or exits the defrosting mode.

[0039] According to a third aspect of the present invention, a condensing unit is provided, comprising:

[0040] A processor, and a memory connected to the processor;

[0041] The memory is used to store computer programs;

[0042] The processor is used to call and execute the computer program in the memory to perform the above-described method.

[0043] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0044] By detecting the inlet and outlet pipe temperatures of the indoor evaporator at the current moment, the system detects whether the four-way valve reversing has failed. After determining that the four-way valve has failed to reversing, the system controls the operating status of the outdoor and indoor unit loads of the condensing unit until the condensing unit successfully enters or exits the defrosting mode. Compared with the existing technology, this system achieves closed-loop detection of four-way valve reversing failure and can take necessary control measures after the four-way valve fails to reversing to ensure that the condensing unit successfully enters or exits the defrosting mode, thereby improving the stability and reliability of the system.

[0045] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating a defrosting control method for a condensing unit according to an exemplary embodiment;

[0047] Figure 2 This is a flowchart illustrating a defrosting control method for a condensing unit according to another exemplary embodiment;

[0048] Figure 3 This is a schematic block diagram illustrating a defrosting control system for a condensing unit according to an exemplary embodiment. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0050] As described in the background section, the relevant technology has a problem where the four-way valve fails to switch, preventing the condensing unit waiting to defrost from entering the defrosting mode, or the condensing unit that has finished defrosting does not have an end-of-defrosting mode, thus affecting the normal use of the condensing unit.

[0051] In order to effectively solve the problems in related technologies, the present invention provides a defrosting control method, system and condensing unit for condensing units, which will be described in detail below.

[0052] Example 1

[0053] Figure 1 This is a flowchart illustrating a defrosting control method for a condensing unit according to an exemplary embodiment, such as... Figure 1 As shown, the method includes:

[0054] Step S11: Detect the operating mode of the condensing unit;

[0055] Step S12: If the current working mode is cooling mode or defrosting mode, detect the current inlet pipe temperature of the indoor evaporator and the current outlet pipe temperature of the indoor evaporator.

[0056] Step S13: Based on the inlet pipe temperature and outlet pipe temperature, determine whether the four-way valve of the condensing unit has failed to switch direction at the current moment. When it is determined that the four-way valve has failed to switch direction, control the working status of the outdoor unit load and indoor unit load of the condensing unit until the condensing unit successfully enters or exits the defrosting mode.

[0057] It should be noted that the technical solution provided in this embodiment is implemented in practice within the controller of the condensing unit, or in an electronic device connected to the controller. The controller includes, but is not limited to, a PLC controller, a microcontroller, an ARM processor, a DSP processor, an FPGA controller, etc.

[0058] Reverse cycle defrosting is a common defrosting method that is low-cost and simple to implement, and is therefore gradually replacing electric heating defrosting in various condensing units. The four-way valve is a crucial component for reverse cycle defrosting. Based on the pressure difference across the piston, the four-way valve automatically reverses the evaporation and condensation processes of the heat exchanger, transforming the evaporator to be defrosted into a "condenser" for hot gas defrosting. After defrosting, the four-way valve reverses again to restore the evaporator to normal cooling mode. Due to the difference in refrigerant flow direction between cooling and defrosting modes, there will be a temperature difference between the inlet and outlet pipe temperatures of the indoor evaporator.

[0059] It is understood that the technical solution provided in this embodiment detects whether the four-way valve reversing has failed by detecting the inlet and outlet pipe temperatures of the indoor evaporator at the current moment. After determining that the four-way valve reversing has failed, the working state of the outdoor and indoor unit loads of the condensing unit is controlled until the condensing unit successfully enters or exits the defrosting mode. Compared with the prior art, this achieves closed-loop detection of four-way valve reversing failure and can take necessary control measures after the four-way valve reversing fails to ensure that the condensing unit successfully enters or exits the defrosting mode, thereby improving the stability and reliability of the system.

[0060] In practice, step S11, which involves detecting the operating mode of the condensing unit, specifically involves:

[0061] When the condensing unit starts up, if the switching time Δt of the four-way valve is greater than the preset switching time ta of the four-way valve, the working mode of the condensing unit is detected.

[0062] It should be noted that the preset switching time ta is set based on historical experience or experimental data. It is understood that if the switching time Δt of the four-way valve is greater than the preset switching time ta, it indicates that the four-way valve may currently have a switching fault. Therefore, under this premise, further detection of the condensing unit's operating mode and control based on the operating mode will reduce the system's computational load, shorten the judgment and calculation process, save system computing resources, and improve system response speed.

[0063] In practice, timing begins from the end of the four-way valve switching and the switching time Δt between the end of the four-way valve switching and the current time is calculated.

[0064] If the switching time Δt exceeds the threshold range (the threshold range is set based on historical experience or experimental data, for example, set to be greater than 1 hour and less than 2 hours), then the current four-way valve switching failure is determined to be an intermittent failure, and the accumulated number of four-way valve switching failures is cleared to zero.

[0065] Specifically, when the condensing unit is powered on for the first time, the timer starts from the moment the compressor starts.

[0066] In practice, step S13 involves determining whether the four-way valve of the condensing unit has failed to switch direction based on the inlet and outlet pipe temperatures, including:

[0067] If the current working mode is cooling mode, and the difference between the outlet pipe temperature Ti-c and the inlet pipe temperature Ti-j is greater than the first preset value Ta (i.e., (Ti-c)-(Ti-j)>Ta), then the four-way valve is determined to have failed to switch.

[0068] If the current working mode is defrosting mode, and the difference between the inlet pipe temperature Ti-j and the outlet pipe temperature Ti-c is greater than the second preset value Tb (i.e., (Ti-j)-(Ti-c)>Tb), then the four-way valve is determined to have failed to switch.

[0069] It should be noted that Ta and Tb are set based on historical experience or experimental data. To improve the detection accuracy of four-way valve switching failure, the ambient temperature range of the storage chamber corresponding to different operating modes can be subdivided into multiple ranges, with different Ta and Tb values ​​corresponding to different ranges, making the detection more accurate.

[0070] It should be noted that in other operating modes or when the four-way valve is determined to have successfully switched, the condensing unit maintains its current operating state.

[0071] Further, in step S13, when it is determined that the four-way valve has failed to switch, the operating status of the outdoor unit load and indoor unit load of the condensing unit is controlled, including:

[0072] If the current working mode is cooling mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is stopped and reset, the indoor fan in the indoor unit load continues to run, and the number of four-way valve switching failures is accumulated (i.e., Ca = Ca + 1, where Ca is the number of four-way valve failures).

[0073] After the first preset time, obtain the ambient temperature Ti-h inside the condenser unit;

[0074] If the ambient temperature Ti-h inside the warehouse is less than the preset warehouse temperature alarm temperature Tbj (i.e. (Ti-h) < Tbj), and the number of times the four-way valve switches is less than the first preset number (i.e. Ca ≤ n1, where n1 is obtained based on historical experience or experimental data), the internal fan is controlled to keep running, and the compressor, external fan, and electronic expansion valve in the external unit load are started.

[0075] After the intake and exhaust pressure difference at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to enter the defrosting mode.

[0076] In defrost mode, when the pressure difference between the suction and discharge at both ends of the piston in the four-way valve reaches the reversing pressure difference again, the four-way valve is de-energized, exiting defrost mode and returning to refrigeration mode.

[0077] It should be noted that the first preset duration is the minimum preset time t for restarting the four-way valve after a reversal failure in cooling mode. b The first preset duration is set based on historical experience or experimental data.

[0078] Outdoor unit loads include, but are not limited to: compressor, outdoor fan, electronic expansion valve, etc.

[0079] Preferably, the method further includes:

[0080] If the current operating mode is cooling mode, and the four-way valve fails to switch, the four-way valve switching failure fault information is defined as a Level 1 manufacturer-level fault S1, and is simultaneously reported to the manufacturer; and / or,

[0081] If the current operating mode is refrigeration mode, and the ambient temperature Ti-h inside the refrigeration unit is greater than or equal to the preset refrigeration temperature alarm temperature Tbj (i.e., (Ti-h)≥Tbj), the four-way valve reversal failure fault information is defined as a first-level user-level fault R1, the condensing unit is controlled to stop running, and the user is simultaneously reminded to perform maintenance or report a repair.

[0082] Understandably, in cooling mode, a failed reversal of the four-way valve can cause a sharp rise in the temperature inside the cold storage. If the ambient temperature is below the preset alarm temperature, the valve can be pushed again. If the ambient temperature exceeds the preset alarm temperature, the unit will shut down immediately, and the user will be notified to report the problem or resolve the issue. This tiered control system reduces unnecessary downtime and ensures timely shutdown in case of potential malfunctions, maximizing the unit's reliability under harsh operating conditions and improving system stability and reliability.

[0083] In practice, when step S13 determines that the four-way valve has failed to switch, controlling the operating status of the outdoor and indoor loads of the condensing unit also includes:

[0084] If the current working mode is defrosting mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is controlled to stop and reset, while the indoor fan in the indoor unit load continues to run;

[0085] After the second preset time period, the internal fan is kept running, and the compressor, external fan and electronic expansion valve in the external unit load are started;

[0086] After the pressure difference between the intake and exhaust at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to exit the defrosting mode.

[0087] It should be noted that the second preset duration is the minimum preset time t for restarting the four-way valve after a failed reversal in defrost mode. c The second preset duration is set based on historical experience or experimental data.

[0088] Outdoor unit loads include, but are not limited to: compressor, outdoor fan, electronic expansion valve, etc.

[0089] Preferably, the method further includes:

[0090] If the current working mode is defrosting mode, and the four-way valve fails to switch, the number of four-way valve switching failures is accumulated (i.e., Ca = Ca + 1, where Ca is the number of four-way valve failures), and the four-way valve switching failure information is defined as a secondary manufacturer-level fault S2, and is simultaneously reported to the manufacturer.

[0091] It should be noted that the reversing failure fault S1 in refrigeration mode and the reversing failure fault S2 in defrosting mode are both manufacturer-level faults, and the condensing unit has no impact on users under these fault conditions. However, if the reversing fails in refrigeration mode and the ambient temperature inside the refrigeration unit exceeds the refrigeration temperature alarm temperature, a user-level fault R1 will be reported. This fault condition has already affected the user's use or caused economic losses to the user, and the user should be promptly notified.

[0092] Understandably, in defrost mode, a failure of the four-way valve to switch direction has minimal impact on the stored items. The compressor system operates intermittently while the internal fan remains on to achieve defrosting (by controlling the outdoor unit load of the condensing unit to stop and reset, at which point the compressor stops working; after a second preset time, the compressor, outdoor fan, and electronic expansion valve in the outdoor unit load are restarted, and the compressor begins operation), thus ensuring a lower temperature inside the storage unit. This tiered control reduces unnecessary downtime and ensures timely shutdown in case of potential failures, maximizing the unit's reliability under harsh operating conditions and improving system stability and reliability.

[0093] It is understandable that in practice, the failure of a four-way valve to switch can be caused by a variety of reasons, such as the four-way valve switching voltage being too low or occasional abnormalities in the system or components.

[0094] It is understood that the technical solution provided in this embodiment detects whether the four-way valve reversing has failed by detecting the difference between the inlet and outlet pipe temperatures of the indoor evaporator in both cooling and defrosting modes and comparing it with preset values. Based on the detection results, the unit is further controlled, attempting to push the valve several times to resolve issues such as low voltage, occasional system or component malfunctions causing the four-way valve reversing failure. This technical solution maximizes the unit's beneficial effects by real-time monitoring of the four-way valve reversing and adjusting the outdoor and indoor unit loads based on detected anomalies. Through tiered control, unnecessary downtime and timely shutdown due to potential faults are reduced, maximizing the unit's reliability under harsh operating conditions and improving system stability and reliability.

[0095] Example 2

[0096] Figure 2 This is a flowchart illustrating a defrosting control method for a condensing unit according to another exemplary embodiment, such as... Figure 2 As shown, the method includes:

[0097] Step S21: When the condensing unit is powered on for the first time, the timer starts from the compressor start time by default; otherwise, the timer starts from the end time of the four-way valve reversal and the reversal time from the end time of the four-way valve reversal to the current time is calculated.

[0098] Step S22: If the switching time exceeds the threshold range, the current four-way valve switching failure is determined to be an intermittent failure, and the accumulated number of four-way valve switching failures is cleared to zero.

[0099] Step S23: If the switching time is greater than the preset switching time of the four-way valve, detect the working mode of the condensing unit;

[0100] Step S24: If the current working mode is cooling mode, and the difference between the outlet pipe temperature and the inlet pipe temperature is greater than the first preset value, then it is determined that the four-way valve has failed to switch, and the process jumps to step S27.

[0101] Step S25: If the current working mode is defrosting mode, and the difference between the inlet pipe temperature and the outlet pipe temperature is greater than the second preset value, then the four-way valve is determined to have failed to switch, and the process jumps to step S28.

[0102] Step S26: In other operating modes or when the four-way valve is determined to have successfully reversed, the condensing unit maintains its current operating state.

[0103] Step S27: Control the operating status of the outdoor unit load and indoor unit load of the condensing unit until the condensing unit successfully enters and exits the defrosting mode, including:

[0104] The system controls the outdoor unit load of the condensing unit to stop and reset, while the indoor fan in the indoor unit load remains running, and accumulates the number of four-way valve reversing failures; the four-way valve reversing failure information is defined as a first-level manufacturer-level failure and reported to the manufacturer simultaneously.

[0105] After the first preset time, obtain the ambient temperature inside the condenser unit where the indoor unit is located.

[0106] If the ambient temperature inside the refrigeration unit is lower than the preset refrigeration temperature alarm temperature, and the number of times the four-way valve switches is less than the first preset number, the internal fan is kept running, and the compressor, external fan, and electronic expansion valve in the external unit load are started; if the ambient temperature inside the refrigeration unit is greater than or equal to the preset refrigeration temperature alarm temperature, the four-way valve switching failure fault information is defined as a first-level user-level fault, the condensing unit is stopped, and the user is simultaneously reminded to perform maintenance or report a repair.

[0107] After the intake and exhaust pressure difference at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to enter the defrosting mode.

[0108] In defrost mode, when the pressure difference between the suction and discharge at both ends of the piston in the four-way valve reaches the reversing pressure difference again, the four-way valve is de-energized, exiting defrost mode and returning to refrigeration mode.

[0109] Step S28: Control the operating status of the outdoor unit load and indoor unit load of the condensing unit until the condensing unit successfully exits the defrosting mode, including:

[0110] If the current working mode is defrosting mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is stopped and reset, while the indoor fan in the indoor unit load continues to run; the number of four-way valve switching failures is accumulated, and the four-way valve switching failure information is defined as a secondary manufacturer-level fault and reported to the manufacturer simultaneously.

[0111] After the second preset time period, the internal fan is kept running, and the compressor, external fan and electronic expansion valve in the external unit load are started;

[0112] After the pressure difference between the intake and exhaust at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to exit the defrosting mode.

[0113] It should be noted that the technical solution provided in this embodiment is implemented in practice within the controller of the condensing unit, or in an electronic device connected to the controller. The controller includes, but is not limited to, a PLC controller, a microcontroller, an ARM processor, a DSP processor, an FPGA controller, etc.

[0114] It is understood that the technical solution provided in this embodiment detects whether the four-way valve reversing has failed by detecting the difference between the inlet and outlet pipe temperatures of the indoor evaporator in both cooling and defrosting modes and comparing it with preset values. Based on the detection results, the unit is further controlled, attempting to push the valve several times to resolve issues such as low voltage, occasional system or component malfunctions causing the four-way valve reversing failure. This technical solution maximizes the unit's beneficial effects by real-time monitoring of the four-way valve reversing and adjusting the outdoor and indoor unit loads based on detected anomalies. Through tiered control, unnecessary downtime and timely shutdown due to potential faults are reduced, maximizing the unit's reliability under harsh operating conditions and improving system stability and reliability.

[0115] Example 3

[0116] Figure 3 This is a schematic block diagram of a defrosting control system 100 for a condensing unit according to an exemplary embodiment, as shown below. Figure 3 As shown, the system 100 includes:

[0117] The first detection module 101 is used to detect the operating mode of the condensing unit;

[0118] The second detection module 102 is used to detect the inlet pipe temperature and the outlet pipe temperature of the indoor evaporator at the current moment if the current working mode is cooling mode or defrosting mode.

[0119] The control module 103 is used to determine whether the four-way valve of the condensing unit has failed to switch direction at the current moment based on the inlet pipe temperature and the outlet pipe temperature, and when the four-way valve is determined to have failed to switch direction, to control the working state of the outdoor unit load and the indoor unit load of the condensing unit until the condensing unit successfully enters or exits the defrosting mode.

[0120] It should be noted that the technical solution provided in this embodiment is implemented in practice within the controller of the condensing unit, or in an electronic device connected to the controller. The controller includes, but is not limited to, a PLC controller, a microcontroller, an ARM processor, a DSP processor, an FPGA controller, etc.

[0121] For the implementation methods and beneficial effects of the above modules, please refer to the description of the relevant steps in the above embodiments, which will not be repeated in this embodiment.

[0122] Reverse cycle defrosting is a common defrosting method that is low-cost and simple to implement, and is therefore gradually replacing electric heating defrosting in various condensing units. The four-way valve is a crucial component for reverse cycle defrosting. Based on the pressure difference across the piston, the four-way valve automatically reverses the evaporation and condensation processes of the heat exchanger, transforming the evaporator to be defrosted into a "condenser" for hot gas defrosting. After defrosting, the four-way valve reverses again to restore the evaporator to normal cooling mode. Due to the difference in refrigerant flow direction between cooling and defrosting modes, there will be a temperature difference between the inlet and outlet pipe temperatures of the indoor evaporator.

[0123] It is understood that the technical solution provided in this embodiment detects whether the four-way valve reversing has failed by detecting the inlet and outlet pipe temperatures of the indoor evaporator at the current moment. After determining that the four-way valve reversing has failed, the working state of the outdoor and indoor unit loads of the condensing unit is controlled until the condensing unit successfully enters or exits the defrosting mode. Compared with the prior art, this achieves closed-loop detection of four-way valve reversing failure and can take necessary control measures after the four-way valve reversing fails to ensure that the condensing unit successfully enters or exits the defrosting mode, thereby improving the stability and reliability of the system.

[0124] Example 4

[0125] A condensing unit according to an exemplary embodiment includes:

[0126] A processor, and a memory connected to the processor;

[0127] The memory is used to store computer programs;

[0128] The processor is used to call and execute the computer program in the memory to perform the above-described method.

[0129] It is understood that the technical solution provided in this embodiment detects whether the four-way valve reversing has failed by detecting the inlet and outlet pipe temperatures of the indoor evaporator at the current moment. After determining that the four-way valve reversing has failed, the working state of the outdoor and indoor unit loads of the condensing unit is controlled until the condensing unit successfully enters or exits the defrosting mode. Compared with the prior art, this achieves closed-loop detection of four-way valve reversing failure and can take necessary control measures after the four-way valve reversing fails to ensure that the condensing unit successfully enters or exits the defrosting mode, thereby improving the stability and reliability of the system.

[0130] Of course, those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.). The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The storage medium can be a memory, magnetic disk, optical disk, etc.

[0131] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A defrosting control method for a condensing unit, characterized in that, include: Detect the operating mode of the condensing unit; If the current working mode is cooling mode or defrosting mode, detect the current inlet pipe temperature of the indoor evaporator and the current outlet pipe temperature of the indoor evaporator. Based on the inlet pipe temperature and outlet pipe temperature, determine whether the four-way valve of the condensing unit has failed to switch direction at the current moment. When it is determined that the four-way valve has failed to switch direction, control the working status of the outdoor unit load and indoor unit load of the condensing unit until the condensing unit successfully enters or exits the defrosting mode. When the four-way valve fails to switch, the operating status of the outdoor and indoor unit loads of the condensing unit is controlled, including: If the current working mode is cooling mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is stopped and reset, the indoor fan in the indoor unit load continues to run, and the number of four-way valve switching failures is accumulated. After the first preset time, obtain the ambient temperature inside the condenser unit where the indoor unit is located. If the ambient temperature inside the warehouse is lower than the preset warehouse temperature alarm temperature, and the number of times the four-way valve switches is less than the first preset number, the internal fan is controlled to keep running, and the compressor, external fan and electronic expansion valve in the external unit load are started. After the intake and exhaust pressure difference at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to enter the defrosting mode. In defrost mode, when the pressure difference between the suction and discharge at both ends of the piston in the four-way valve reaches the reversing pressure difference again, the four-way valve is de-energized, exiting defrost mode and returning to refrigeration mode. When the four-way valve fails to switch, the method of controlling the operating status of the outdoor unit load and indoor unit load of the condensing unit further includes: If the current working mode is defrosting mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is controlled to stop and reset, while the indoor fan in the indoor unit load continues to run; After the second preset time period, the internal fan is kept running, and the compressor, external fan and electronic expansion valve in the external unit load are started; After the pressure difference between the intake and exhaust at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to exit the defrosting mode.

2. The method according to claim 1, characterized in that, The step of determining whether the four-way valve of the condensing unit has failed to switch direction at the current moment based on the inlet pipe temperature and the outlet pipe temperature includes: If the current working mode is cooling mode, and the difference between the outlet pipe temperature and the inlet pipe temperature is greater than a first preset value, then the four-way valve is determined to have failed to switch. If the current working mode is defrosting mode, and the difference between the inlet pipe temperature and the outlet pipe temperature is greater than the second preset value, then the four-way valve is determined to have failed to switch.

3. The method according to claim 1, characterized in that, Also includes: If the current operating mode is cooling mode, and the four-way valve fails to switch, the four-way valve switching failure fault information is defined as a Level 1 manufacturer-level fault and simultaneously reported to the manufacturer; and / or, If the current operating mode is refrigeration mode, and the ambient temperature inside the refrigeration unit is greater than or equal to the preset refrigeration temperature alarm temperature, the four-way valve reversal failure fault information is defined as a first-level user-level fault, the condensing unit is controlled to stop running, and the user is simultaneously reminded to perform maintenance or report a repair.

4. The method according to claim 1, characterized in that, Also includes: If the current working mode is defrosting mode, and the four-way valve fails to switch, the number of four-way valve switching failures is accumulated, and the four-way valve switching failure information is defined as a secondary manufacturer-level fault and reported to the manufacturer simultaneously.

5. The method according to any one of claims 2 to 4, characterized in that, Also includes: Start timing from the end of the four-way valve switching and calculate the switching time from the end of the four-way valve switching to the current time; If the switching time exceeds the threshold range, the current four-way valve switching failure is determined to be an intermittent failure, and the accumulated number of four-way valve switching failures is cleared to zero.

6. The method according to claim 5, characterized in that, Also includes: When the condensing chiller unit is powered on for the first time, the timer starts from the moment the compressor starts.

7. The method according to claim 6, characterized in that, The specific operating mode of the condenser unit being tested is as follows: When the condensing unit starts, if the reversing time is longer than the preset reversing time of the four-way valve, the working mode of the condensing unit is detected.

8. A defrosting control system for a condensing unit, characterized in that, include: The first detection module is used to detect the operating mode of the condensing unit; The second detection module is used to detect the inlet pipe temperature and the outlet pipe temperature of the indoor evaporator at the current moment if the current working mode is cooling mode or defrosting mode. The control module is used to determine whether the four-way valve of the condensing unit has failed to switch direction at the current moment based on the inlet pipe temperature and the outlet pipe temperature, and when the four-way valve is determined to have failed to switch direction, control the working state of the outdoor unit load and the indoor unit load of the condensing unit until the condensing unit successfully enters or exits the defrosting mode. When the four-way valve fails to switch, the operating status of the outdoor and indoor unit loads of the condensing unit is controlled, including: If the current working mode is cooling mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is stopped and reset, the indoor fan in the indoor unit load continues to run, and the number of four-way valve switching failures is accumulated. After the first preset time, obtain the ambient temperature inside the condenser unit where the indoor unit is located. If the ambient temperature inside the warehouse is lower than the preset warehouse temperature alarm temperature, and the number of times the four-way valve switches is less than the first preset number, the internal fan is controlled to keep running, and the compressor, external fan and electronic expansion valve in the external unit load are started. After the intake and exhaust pressure difference at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to enter the defrosting mode. In defrost mode, when the pressure difference between the suction and discharge at both ends of the piston in the four-way valve reaches the reversing pressure difference again, the four-way valve is de-energized, exiting defrost mode and returning to refrigeration mode. When the four-way valve fails to switch, the method of controlling the operating status of the outdoor unit load and indoor unit load of the condensing unit further includes: If the current working mode is defrosting mode, and the four-way valve fails to switch, the outdoor unit load of the condensing unit is controlled to stop and reset, while the indoor fan in the indoor unit load continues to run; After the second preset time period, the internal fan is kept running, and the compressor, external fan and electronic expansion valve in the external unit load are started; After the pressure difference between the intake and exhaust at both ends of the piston in the four-way valve reaches the reversing pressure difference, the four-way valve is energized and reversed to exit the defrosting mode.

9. A condensing unit, characterized in that, include: A processor, and a memory connected to the processor; The memory is used to store computer programs; The processor is used to call and execute the computer program in the memory to perform the method according to any one of claims 1 to 7.

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