A programmable control system and method for a freezer refrigeration unit

Abstract

The application discloses a programmable control system and method for a refrigeration and freezing unit, which comprises an interaction module, a detection module and a control protection module; the interaction module is used for setting or adjusting logical control parameters; the detection module is used for collecting operation parameters of the refrigeration and freezing unit; and the control module is used for controlling the operation state of the refrigeration and freezing unit according to the collected operation parameters of the refrigeration and freezing unit and in combination with the set or adjusted logical control parameters; the interaction module is arranged to pre-set or adjust the logical control parameters of the system, to realize adaptive modification of the control logic according to the self demand of the unit, and to meet the control demands of different units; the operation state of the unit is controlled by the pre-set or adjusted logical control parameters and the unit operation parameters collected by the detection module, so that automatic control and protection of the compressor are realized, and effective guarantee is provided for the operation stability of the unit.

Description

Technical Field

[0001] This invention belongs to the field of compressor control technology, and specifically relates to a programmable control system and method for refrigeration units. Background Technology

[0002] Refrigeration units generally include components such as compressors, condensers, condenser fans, high-pressure liquid receivers, and evaporators. Among them, compressors are generally fixed-frequency compressors. When the system is working, the compressor discharges high-temperature, high-pressure refrigerant gas into the condenser. The condenser fan enhances the heat exchange in the condenser, and then the refrigerant gas is cooled to high-pressure liquid and enters the high-pressure liquid receiver. Afterward, it passes through a dryer filter to remove any impurities and moisture that may be present in the system. It then enters the evaporator through a throttling structure, and after heat exchange, it is transformed into low-temperature, low-pressure refrigerant gas. Finally, it flows back to the compressor through the compressor suction port.

[0003] As a key component of refrigeration and cold storage units, ensuring the stability of the compressor's operation is crucial for the long-term stable operation of the unit. In actual use, refrigeration and cold storage units may experience compressor malfunctions due to factors such as equipment installation, component configuration, external environment, or internal system issues. If these faults are not detected and eliminated in time, they will cause long-term damage to the compressor, potentially leading to complete compressor failure. Furthermore, due to the wide variety of compressor types, complex operating environments, and the fact that different environments and models of units often require different operating modes, existing refrigeration and cold storage unit control systems often have only one operating mode. Manufacturers can only replace the control system according to actual needs, increasing costs and resulting in relatively lower efficiency and reliability. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention provides a programmable control system and method for refrigeration and freezing units, so as to solve the technical problems of existing refrigeration and freezing unit control systems having a single working mode, low control efficiency and poor reliability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a programmable control system for a refrigeration unit, including an interaction module, a detection module, and a control and protection module; the interaction module is used to set or adjust logic control parameters; the detection module is used to collect operating parameters of the refrigeration unit; the control module is used to control the operating status of the refrigeration unit based on the collected operating parameters of the refrigeration unit and in combination with the pre-set or adjusted logic control parameters.

[0007] The detection module includes a temperature detection module, a power detection module, and a switch signal detection module;

[0008] The temperature detection module is used to collect the real-time exhaust temperature of the compressor, the real-time condensing temperature of the condenser fan, and the real-time ambient temperature of the compressor; the power detection module is used to detect the power status of the compressor and obtain the power phase state detection result of the compressor; the switch signal detection module is used to detect the switching status of the on / off switch in the compressor and obtain the switching status signal of the on / off switch in the compressor.

[0009] The control and protection module includes an exhaust protection module, a condenser fan control module, a solenoid valve / expansion valve control module, a crankshaft heating belt control module, a first start-stop control module, and a second start-stop control module.

[0010] The exhaust protection module is used to provide overheat protection for the compressor based on the real-time exhaust temperature. The condenser fan control module is used to regulate and control the condenser fan based on the real-time condensing temperature. The solenoid valve / expansion valve control module is used to control the start / stop of the liquid injection solenoid valve in the compressor or to adjust the opening of the electronic expansion valve in the compressor based on the real-time exhaust temperature. The crankshaft heating belt control module is used to control the power supply to the crankcase heating belt in the compressor based on the real-time ambient temperature. The first start / stop control module is used to control the start / stop of the compressor or provide abnormal shutdown protection based on the power supply phase detection results. The second start / stop control module is used to control the start / stop of the compressor and provide abnormal shutdown protection based on the on / off status signal of the on / off switch in the compressor.

[0011] Furthermore, the temperature detection module includes an exhaust temperature sensor, a condensation temperature sensor, and an ambient temperature sensor.

[0012] The exhaust temperature sensor is used to collect the real-time exhaust temperature of the compressor; the condensing temperature sensor is used to collect the real-time condensing temperature of the condenser fan; and the ambient temperature sensor is used to collect the real-time ambient temperature of the compressor.

[0013] Furthermore, the switch signal detection module includes a high-pressure switch status detection module, a low-pressure switch status detection module, a 220V power-on signal detection module, and a passive switch status detection module.

[0014] The high-pressure switch status detection module is used to detect the switching status of the high-pressure switch in the compressor and obtain the switching status signal of the high-pressure switch; the low-pressure switch status detection module is used to detect the switching status of the low-pressure switch in the compressor and obtain the switching status signal of the low-pressure switch; the 220V start-up signal detection module is used to acquire the 220V start-up signal of the compressor; and the passive switch status detection module is used to acquire the switching status signal of the passive switch in the compressor.

[0015] Furthermore, the second start-stop control module includes a start-stop control unit A and a start-stop control unit B;

[0016] The start / stop control unit A is used to control the compressor to start / stop and protect it from abnormal shutdown based on the switch status signal of the high-pressure switch or the switch status signal of the low-pressure switch; the start / stop control unit B is used to control the compressor to start / stop based on the 220V start signal of the compressor or the switch status signal of the passive switch in the compressor.

[0017] Furthermore, the control system also includes a display module; the display module is used to display the compressor's operating status parameters or fault codes.

[0018] Furthermore, the interaction module includes three interaction buttons; the first interaction button is a value increment button, used to increase the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameter; the second interaction button is a value decrement button, used to decrease the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameter; the third interaction button is a confirmation button, used to confirm that the current value of the parameter to be set is the new setting value when setting or adjusting the logic control parameter.

[0019] Furthermore, it also includes an alarm output module; the alarm output module is used for fault alarm signals.

[0020] Furthermore, it also includes a DIP switch; the DIP switch is used to select the control mode.

[0021] Furthermore, it also includes a liquid hammer protection module;

[0022] The temperature detection module is also used to collect the real-time return gas temperature of the compressor;

[0023] The liquid slugging protection module is used to determine the liquid slugging state of the compressor based on the real-time exhaust temperature of the compressor, the real-time condensing temperature of the condenser fan, and the real-time return gas temperature of the compressor, and to perform liquid slugging protection control on the compressor based on the liquid slugging state determination result.

[0024] The present invention also provides a programmable control method for refrigeration and freezing units, utilizing the aforementioned programmable control system for refrigeration and freezing units;

[0025] The control method includes:

[0026] The system collects real-time discharge temperature of the compressor, real-time condensing temperature of the condenser fan, and real-time ambient temperature of the compressor.

[0027] The power supply status of the compressor is detected, and the power supply phase status detection results of the compressor are obtained;

[0028] The on / off state of the on / off switch in the compressor is detected, and the on / off state signal of the on / off switch in the compressor is obtained;

[0029] The compressor is protected against overheating based on its real-time exhaust temperature.

[0030] The condenser fan is adjusted and controlled according to its real-time condensing temperature.

[0031] Based on the real-time discharge temperature of the compressor, the start / stop control of the liquid injection solenoid valve in the compressor or the opening degree adjustment of the electronic expansion valve in the compressor are performed.

[0032] The power supply to the crankcase heating belt in the compressor is controlled based on the real-time ambient temperature of the compressor.

[0033] Based on the power phase state detection results of the compressor, start-up and shutdown control and abnormal shutdown protection of the compressor are implemented;

[0034] Based on the on / off status signal of the on / off switch in the compressor, the compressor is controlled to start / stop and protected against abnormal shutdown.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] This invention provides a programmable control system and method for refrigeration and cold storage units. By setting up an interactive module, the system's logic control parameters can be pre-set or adjusted, enabling adaptive modification of the control logic according to the unit's own needs. This satisfies the control requirements of different units, and combined with its programmable characteristics, the actual control logic can be flexibly changed according to actual usage needs. By controlling the unit's operating status through pre-set or adjusted logic control parameters and unit operating parameters collected by the detection module, the system achieves automatic control and protection of the compressor, effectively ensuring the stability of unit operation. The system has clear logic, simple structure, and wide applicability, while significantly improving the control efficiency and reliability of the unit. Attached Figure Description

[0037] Figure 1This is a schematic diagram of the programmable control system for a refrigeration unit as described in the embodiment.

[0038] Figure 2 This is a flowchart of the compressor start-up control logic in the embodiment.

[0039] The system consists of 1 control board, 2 display module, 3 interactive module, 4 alarm output module, and 5 DIP switch. Detailed Implementation

[0040] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0041] This invention provides a programmable control system for a refrigeration unit, comprising an interaction module, a detection module, a control and protection module, a display module, an alarm output module, a DIP switch, and a liquid slugging protection module. The interaction module is used to set or adjust logic control parameters. The detection module is used to collect operating parameters of the refrigeration unit. The control module is used to control the operating status of the refrigeration unit based on the collected operating parameters and pre-set or adjusted logic control parameters. The display module is used to display the compressor's operating status parameters or fault codes. The alarm output module is used to output fault alarm signals. The DIP switch is used to select the control mode. The liquid slugging protection module is used to determine the liquid slugging state of the compressor and, based on the determination result, to perform liquid slugging protection control on the compressor.

[0042] In this invention, the interactive module includes three interactive buttons; the first interactive button is a value increment button, used to increase the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameter; the second interactive button is a value decrement button, used to decrease the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameter; the third interactive button is a confirmation button, used to confirm that the current value of the parameter to be set is the new setting value when setting or adjusting the logic control parameter.

[0043] In this invention, the detection module includes a temperature detection module, a power supply detection module, and a switch signal detection module. The temperature detection module is used to collect real-time discharge temperature of the compressor, real-time condensing temperature of the condenser fan, real-time ambient temperature of the compressor, and real-time return gas temperature of the compressor. The power supply detection module is used to detect the power supply status of the compressor and obtain the power supply phase state detection result. The switch signal detection module is used to detect the switching status of the on / off switch in the compressor and obtain the switching status signal of the on / off switch in the compressor.

[0044] Specifically, the temperature detection module includes an exhaust temperature sensor, a condenser temperature sensor, an ambient temperature sensor, and a return gas temperature sensor; wherein, the exhaust temperature sensor is used to collect the real-time exhaust temperature of the compressor; the condenser temperature sensor is used to collect the real-time condenser temperature of the condenser fan; the ambient temperature sensor is used to collect the real-time ambient temperature of the compressor; and the return gas temperature sensor is used to collect the real-time return gas temperature of the compressor.

[0045] Specifically, the switch signal detection module includes a high-pressure switch status detection module, a low-pressure switch status detection module, a 220V start-up signal detection module, and a passive switch status detection module. The high-pressure switch status detection module detects the switching status of the high-pressure switch in the compressor to obtain its switching status signal. The low-pressure switch status detection module detects the switching status of the low-pressure switch in the compressor to obtain its switching status signal. The 220V start-up signal detection module acquires the 220V start-up signal of the compressor. The passive switch status detection module acquires the switching status signal of the passive switch in the compressor.

[0046] In this invention, the control and protection module includes an exhaust protection module, a condenser fan control module, a solenoid valve / expansion valve control module, a crankshaft heating belt control module, a first start-stop control module, and a second start-stop control module. The exhaust protection module is used to provide overheat protection for the compressor based on its real-time exhaust temperature. The condenser fan control module is used to regulate and control the condenser fan based on its real-time condensing temperature. The solenoid valve / expansion valve control module is used to control the start-stop of the liquid injection solenoid valve in the compressor or to adjust the opening of the electronic expansion valve in the compressor based on its real-time exhaust temperature. The crankshaft heating belt control module is used to heat the crankcase in the compressor based on its real-time ambient temperature. The compressor is powered on and off; the first start-stop control module is used to control the compressor to start / stop or provide abnormal shutdown protection based on the power phase detection result of the compressor; the second start-stop control module is used to control the compressor to start / stop and provide abnormal shutdown protection based on the switch status signal of the on / off switch in the compressor; wherein, the second start-stop control module includes start-stop control unit A and start-stop control unit B; the start-stop control unit A is used to control the compressor to start / stop and provide abnormal shutdown protection based on the switch status signal of the high-pressure switch or the low-pressure switch; the start-stop control unit B is used to control the compressor to start / stop based on the 220V start signal of the compressor or the switch status signal of the passive switch in the compressor.

[0047] In this invention, the liquid slugging protection module is used to determine the liquid slugging state of the compressor based on the real-time exhaust temperature of the compressor, the real-time condensing temperature of the condenser fan, and the real-time return gas temperature of the compressor, and to perform liquid slugging protection control on the compressor based on the liquid slugging state determination result.

[0048] The present invention also provides a programmable control method for refrigeration and freezing units, comprising the following steps:

[0049] The system collects real-time discharge temperature of the compressor, real-time condensing temperature of the condenser fan, and real-time ambient temperature of the compressor.

[0050] The power supply status of the compressor is detected, and the power supply phase status detection results of the compressor are obtained;

[0051] The on / off state of the on / off switch in the compressor is detected, and the on / off state signal of the on / off switch in the compressor is obtained;

[0052] The compressor is protected against overheating based on its real-time exhaust temperature.

[0053] The condenser fan is adjusted and controlled according to its real-time condensing temperature.

[0054] Based on the real-time discharge temperature of the compressor, the start / stop control of the liquid injection solenoid valve in the compressor or the opening degree adjustment of the electronic expansion valve in the compressor are performed.

[0055] The power supply to the crankcase heating belt in the compressor is controlled based on the real-time ambient temperature of the compressor.

[0056] Based on the power phase state detection results of the compressor, start-up and shutdown control and abnormal shutdown protection of the compressor are implemented;

[0057] Based on the on / off status signal of the on / off switch in the compressor, the compressor is controlled to start / stop and protected against abnormal shutdown.

[0058] The programmable control system and method described in this invention utilize an interactive module to pre-set or adjust the system's logic control parameters, enabling adaptive modification of the control logic according to the unit's own needs and meeting the control requirements of different units. By controlling the unit's operating status through pre-set or adjusted logic control parameters and unit operating parameters collected by the detection module, the system achieves automatic control and protection of the compressor, effectively ensuring the stability of unit operation.

[0059] Example

[0060] In this embodiment, the control process of a certain refrigeration unit is taken as an example; wherein, the refrigeration unit includes a compressor and a condenser fan, and the compressor is a fixed-frequency compressor.

[0061] As attached Figure 1 As shown, this embodiment provides a programmable control system for a refrigeration unit, including a control board 1 and a detection module, a control protection module, a display module 2, an interaction module 3, an alarm output module 4, a DIP switch 5, a liquid hammer protection module, and a communication module disposed on or connected to the control board 1.

[0062] The detection module includes a temperature detection module, a power supply detection module, and a switch signal detection module.

[0063] The temperature detection module is used to collect the real-time exhaust temperature of the compressor, the real-time condensing temperature of the condenser fan, the real-time ambient temperature of the compressor, and the real-time return gas temperature of the compressor. Specifically, the temperature detection module includes an exhaust temperature sensor, a condensing temperature sensor, an ambient temperature sensor, and a return gas temperature sensor. The exhaust temperature sensor is used to collect the real-time exhaust temperature of the compressor; the condensing temperature sensor is used to collect the real-time condensing temperature of the condenser fan; the ambient temperature sensor is used to collect the real-time ambient temperature of the compressor; and the return gas temperature sensor is used to collect the real-time return gas temperature of the compressor.

[0064] The power detection module is used to detect the power status of the compressor and obtain the power phase state detection results of the compressor.

[0065] The switch signal detection module is used to detect the switching status of the on / off switches in the compressor and obtain the switching status signals of the on / off switches in the compressor. Specifically, the switch signal detection module includes a high-pressure switch status detection module, a low-pressure switch status detection module, a 220V start-up signal detection module, and a passive switch status detection module. The high-pressure switch status detection module is used to detect the switching status of the high-pressure switch in the compressor and obtain the high-pressure switch status signal. The low-pressure switch status detection module is used to detect the switching status of the low-pressure switch in the compressor and obtain the low-pressure switch status signal. The 220V start-up signal detection module is used to obtain the 220V start-up signal of the compressor. The passive switch status detection module is used to obtain the switching status signals of the passive switches in the compressor.

[0066] The control and protection module includes an exhaust protection module, a condenser fan control module, a solenoid valve / expansion valve control module, a crankshaft heating belt control module, a first start-stop control module, and a second start-stop control module. Specifically, the exhaust protection module is used to provide overheat protection for the compressor based on the real-time exhaust temperature; the condenser fan control module is used to regulate and control the condenser fan based on the real-time condensing temperature; the solenoid valve / expansion valve control module is used to control the start-stop of the liquid injection solenoid valve in the compressor or to adjust the opening of the electronic expansion valve in the compressor based on the real-time exhaust temperature; the crankshaft heating belt control module is used to control the power supply to the crankcase heating belt in the compressor based on the real-time ambient temperature; the first start-stop control module is used to control the start-stop of the compressor or provide abnormal shutdown protection based on the power supply phase detection results; and the second start-stop control module is used to control the start-stop of the compressor and provide abnormal shutdown protection based on the on / off status signal of the on / off switch in the compressor.

[0067] It should be noted that the second start-stop control module includes a start-stop control unit A and a start-stop control unit B; the start-stop control unit A is used to control the compressor to start and stop and protect against abnormal shutdown based on the switch status signal of the high-pressure switch or the switch status signal of the low-pressure switch; the start-stop control unit B is used to control the compressor to start and stop based on the 220V start signal of the compressor or the switch status signal of the passive switch in the compressor.

[0068] The display module is used to display the compressor's operating status or fault codes; wherein, the display module includes surface-mount LEDs and LED display digital tubes; specifically, the surface-mount LEDs are used for phase power-on indication, low-voltage 3.3V / 5V power-on indication, relay power-on indication, and 220V power-on signal power-on indication; the LED display digital tubes are used for parameter or fault code display; preferably, the LED display digital tubes have three display digits and the display font is red.

[0069] The interactive module is used to set or adjust logic control parameters. It includes three interactive buttons: the first button is an increment button, used to increase the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameters; the second button is a decrement button, used to decrease the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameters; and the third button is a confirmation button, used to confirm that the current value of the parameter to be set is the new setting value when setting or adjusting the logic control parameters.

[0070] The alarm output module is used to output a fault alarm signal; wherein, the alarm output module adopts a buzzer alarm.

[0071] The DIP switch is used to select the control mode; wherein the DIP switch includes three switch positions, the first switch position is used to select three-phase power supply or single-phase power supply, the second switch position is used to select high voltage protection lockout or high voltage protection not lockout, and the third switch position is used to select whether to perform liquid hammer protection determination.

[0072] The communication module is used for communication between various component modules in the system; preferably, the communication module is a 485 communication module.

[0073] The programmable control system for refrigeration units described in this embodiment allows for the pre-setting and modification of various system parameters through the interactive and display modules. The control mode is selected via a DIP switch, enabling corresponding compressor function switching. During data acquisition and feedback, real-time temperature data, the status of the liquid injection solenoid valve, the high-pressure switch status, and the low-pressure switch status are all displayed on LED digital tubes. During data analysis and automatic control judgment, the compressor's operating status is assessed based on the current real-time temperature values. When an abnormal temperature is detected, the corresponding components are automatically controlled to adjust the compressor back to normal operation. If the system cannot automatically adjust, a shutdown protection mechanism is implemented, and a corresponding alarm is output. The compressor's start-up and shutdown are controlled based on the high-pressure and low-pressure switches; in case of abnormalities, a shutdown protection mechanism is implemented, and a fault alarm is output. Based on the input power supply, the power detection module controls the compressor's start-up and shutdown; in case of power abnormalities, a shutdown protection mechanism is implemented, and a fault alarm is output. The compressor's start-up and shutdown are controlled based on the 220V start-up signal input to the compressor or the switch status signal of the passive switch within the compressor.

[0074] It should be noted that the control board 1 also has a reserved temperature probe interface, a switch interface, and a relay interface; wherein, the temperature probe interface is used to connect a temperature probe to introduce a temperature feedback signal; the switch interface is used to connect a passive switch to detect the switch input of the passive switch; and the relay interface is used to connect a 220V output control to control the preset power supply.

[0075] Working principle:

[0076] As attached Figure 2 As shown in this embodiment, the programmable control system for refrigeration units has the following control principle:

[0077] 1. Compressor start-up and shutdown control process

[0078] 1.1 The compressor start-up control logic is as follows: When the refrigeration unit is started, the condenser fan is started first, and after the set compressor start-up delay time, the compressor is started; wherein, the main circuit refrigeration solenoid valve in the refrigeration unit starts synchronously with the condenser fan, and the display code for the compressor start-up delay time is F21.

[0079] 1.2 Compressor shutdown control logic, specifically: When the compressor is running, the compressor will shut down when either the 220V start signal of the compressor or the switch status signal of the passive switch in the compressor is disconnected; after the compressor stops, it can only be restarted after the set minimum compressor shutdown time; wherein, the compressor shutdown control logic only applies to the natural control shutdown method under normal conditions, and the main circuit refrigeration solenoid valve is synchronously disconnected when the compressor stops, and the display code for the minimum compressor shutdown time is F17.

[0080] 2. Compressor exhaust protection control process

[0081] In this embodiment, the compressor is overheated and protected by real-time exhaust temperature collected by an exhaust temperature sensor. Specifically, the compressor's real-time exhaust temperature is collected by the exhaust temperature sensor. When the compressor's real-time exhaust temperature reaches the set value T1, the LED display shows an exhaust protection alarm; simultaneously, the alarm buzzer continuously sounds, and the compressor continues to run. When the compressor's real-time exhaust temperature continues to rise, and further increases from the set value T1 to the set value T2, the compressor shuts down for protection, the LED display shows the corresponding fault, and the alarm buzzer continues to sound. The alarm will sound until the real-time discharge temperature of the compressor drops to the set value T0. At this point, the alarm will be silenced, and the compressor can be restarted. Because the discharge protection shutdown time interval does not refer to the set minimum shutdown time, preferably, the discharge protection shutdown time is 10 minutes. The set value T0 is the compressor discharge protection reset temperature, and its display code is F07. The set value T1 is the compressor discharge protection alarm temperature, and its display code is F05. The set value T2 is the compressor discharge protection shutdown temperature, and its display code is F06.

[0082] In the event of a compressor exhaust protection shutdown, the condenser fan operates according to operating mode 1. Specifically, after the compressor exhaust protection shutdown, the condenser fan runs for a delay until the real-time exhaust temperature of the compressor is less than the set value T0 or the compressor exhaust protection shutdown exceeds the set value t. Here, the set value t is the condenser fan delay shutdown time during compressor temperature protection, and the display code for the condenser fan delay shutdown time during compressor temperature protection is F23. If the controller's power-on / off signal remains in the on state, the condenser fan remains on and will not undergo the aforementioned shutdown determination.

[0083] When the exhaust temperature sensor malfunctions, the LED display digital tube will output the corresponding fault information, and the alarm buzzer will continuously sound an alarm. At this time, the compressor exhaust protection function will not be activated.

[0084] 3. Condenser fan control

[0085] In this embodiment, the condenser fan is automatically controlled by a condenser temperature sensor. When the 220V start signal of the compressor and the switch status signal of the passive switch in the compressor are simultaneously connected, the condenser fan begins to perform start-stop logic determination. It should be noted that the condenser fan starts first, and the compressor starts later. After the compressor stops, the condenser fan shuts down after a preset time. The preset time is the condenser fan delayed shutdown time, and the display code for the condenser fan delayed shutdown time is F22.

[0086] The control modes of the condenser fan include chopper speed regulation and on / off mode; wherein, the corresponding control mode is selected according to the fan type setting; that is, when the parameter set for the fan type is 0 / 1, the control mode of the condenser fan is selected as chopper speed regulation or on / off mode; wherein, the display code for the fan type setting is F26.

[0087] Specifically, when the start-stop mode is selected, the control process of the condenser fan is as follows: when the real-time condensing temperature of the condenser fan is greater than or equal to the condenser fan start-up coil temperature, the condenser fan starts running; when the real-time condensing temperature of the condenser fan is less than the condenser fan stop-down condensing temperature, the condenser fan stops; wherein, the display code for the condenser fan stop-down condensing temperature is F10, and the display code for the condenser fan start-up coil temperature is F11.

[0088] Specifically, when the speed regulation mode is selected, the control process of the condenser fan is as follows: assuming that the operating speed of the condenser fan is divided into five levels, the speed of the condenser fan is adjusted according to the preset parameter values ​​and the real-time condensing temperature of the condenser fan detected by the condensing temperature sensor.

[0089] The speed regulation logic is as follows:

[0090] When the real-time condensing temperature of the condenser fan meets the following conditions: condenser fan shutdown condensing temperature < condenser fan real-time condensing temperature ≤ condenser fan start-up coil temperature, adjust the condenser fan speed to level 1 (ultra-low fan speed); when the real-time condensing temperature of the condenser fan meets the following conditions: condenser fan shutdown condensing temperature +5 < condenser fan real-time condensing temperature ≤ condenser fan start-up coil temperature +5, adjust the condenser fan speed to level 2 (low fan speed); when the real-time condensing temperature of the condenser fan meets the following conditions: condenser fan shutdown condensing temperature +10 < condenser fan real-time condensing temperature ≤ condenser fan start-up coil temperature +10, adjust the condenser fan speed to level 3 (medium fan speed); when the real-time condensing temperature of the condenser fan meets the following conditions: condenser fan real-time condensing temperature > condenser fan shutdown condensing temperature +15, adjust the condenser fan speed to level 4 (high fan speed); when the real-time condensing temperature of the condenser fan is less than the condenser fan shutdown condensing temperature, the condenser fan is shut down.

[0091] It should be noted that the setting value for Level 1 (ultra-low fan speed) is obtained by setting the ultra-low fan speed duty cycle of the condenser fan; the setting value for Level 2 (low fan speed) is obtained by setting the low fan speed duty cycle of the condenser fan; the setting value for Level 3 (medium fan speed) is obtained by setting the medium fan speed duty cycle of the condenser fan; and the setting value for Level 4 (high fan speed) is obtained by setting the high fan speed duty cycle of the condenser fan. The display code for the ultra-low fan speed duty cycle of the condenser fan is F00, the display code for the low fan speed duty cycle is F01, the display code for the medium fan speed duty cycle is F02, and the display code for the high fan speed duty cycle is F03.

[0092] It should be noted that the condenser fan control module regulates the condenser fan to adjust the condensing temperature; when the condenser fan's heat dissipation is insufficient or other reasons cause the condensing temperature to continue rising, it also provides compressor shutdown protection logic; the compressor shutdown protection logic is as follows:

[0093] When the condenser fan stops and the condensing temperature is greater than or equal to the coil temperature protection alarm temperature, a fault code is output and displayed on the LED digital display, while a buzzer alarm is also sounded. The display code for the coil temperature protection alarm temperature is F12. When the condenser fan stops and the condensing temperature is greater than or equal to the coil temperature protection shutdown temperature, a fault code is output and displayed on the LED digital display, while a buzzer alarm is also sounded. At this time, the compressor stops. The display code for the coil temperature protection shutdown temperature is F13. When the condensing temperature fault alarm signal continues until the temperature drops to the coil temperature protection reset temperature, the condensing temperature fault alarm signal is cleared, and the compressor is allowed to restart. The display code for the coil temperature protection reset temperature is F14. Because the compressor shutdown time interval is not based on the minimum compressor shutdown time during condensing temperature protection shutdown, the compressor shutdown time interval is fixed at 10 minutes. The display code for the minimum compressor shutdown time is F17.

[0094] Under temperature protection conditions, the condenser fan operates in operating mode 2. Specifically, after the compressor stops, the condenser fan runs for a delay until the exhaust temperature is lower than the coil temperature protection reset temperature or exceeds the temperature protection fan delay shutdown time setting value t. If the power on / off signal is always in the on state, the condenser fan will remain on and will not perform this shutdown judgment.

[0095] 4. Control of the injection solenoid valve and electronic expansion valve

[0096] When the compressor is running, if the exhaust temperature sensor detects that the real-time exhaust temperature of the compressor is greater than or equal to the opening temperature of the liquid injection solenoid valve, the liquid injection valve and the electronic valve will open; the display code for the opening temperature of the liquid injection solenoid valve is F08; if the exhaust temperature sensor detects that the exhaust temperature is less than or equal to the opening temperature of the liquid injection solenoid valve, the liquid injection solenoid valve will close; during the operation of the liquid injection solenoid valve / electronic expansion valve, the protection logic corresponding to exhaust superheat is closed.

[0097] Specifically, the electronic expansion valve operates as follows: when the electronic expansion valve opens, it first opens for 30 seconds at the initial value of the set electronic expansion valve opening degree, and then dynamically adjusts the opening degree according to the real-time exhaust temperature of the compressor; the display code for the electronic expansion valve opening degree is F15; at the same time, the real-time exhaust temperature of the compressor is maintained at the opening temperature of the liquid injection solenoid valve; when the exhaust temperature sensor is abnormal, the LED display digital tube will output the corresponding fault display, and the buzzer alarm will continuously output an alarm sound. At this time, the liquid injection solenoid valve / electronic expansion valve will not make an opening determination.

[0098] 5. Control of crankshaft heating belt:

[0099] Crankcase heater activation conditions: When the outdoor ambient temperature is ≤ the set value of the heater opening temperature and the compressor is in a stopped state, the crankcase heater is energized; the display code for the heater opening temperature is F24; when the outdoor ambient temperature is ≥ the set value of the heater opening temperature or the compressor starts running, the crankcase heater is de-energized; when the ambient temperature sensor fails and the compressor stops, the crankcase heater is energized, and when the compressor is running, the crankcase heater is de-energized.

[0100] 6. Control of the main cooling solenoid valve

[0101] The main circuit solenoid valve and the condenser fan open simultaneously, and the compressor disconnects simultaneously.

[0102] 7. High and low pressure protection control

[0103] Upon receiving the compressor start-up signal, the status of the high-pressure and low-pressure switches is checked. If they are open, an alarm is triggered, and the compressor, fan, and main circuit solenoid valve are not powered on. If either the high-pressure or low-pressure switch is closed and the reset time exceeds the specified time, the compressor, fan, and main circuit solenoid valve operate normally according to the control logic. The display code for the pressure switch reset time is F20. If the high-pressure and low-pressure switches are detected to be open during compressor operation, the compressor is de-energized, the main circuit solenoid valve is de-energized, and the condenser fan is de-energized after a delay after the low-pressure switch protection time or the high-pressure switch protection time has elapsed. The display code for the low-pressure switch protection time is F18, and the display code for the high-pressure switch protection time is F19.

[0104] 8. High-voltage lockout function

[0105] If three consecutive protection cycles occur within the high-pressure switch lockout interval, the system enters a lockout state and flashes alarm HP. The display code for the high-pressure switch lockout interval is F25. At this time, the compressor, main circuit solenoid valve, and condenser fan are de-energized sequentially, and the compressor will not start until power is restored to reset the fault. If the cumulative high-pressure protection count is less than three, and the compressor is de-energized due to other reasons, the cumulative high-pressure protection count is reset to zero, and the timing and counting restart.

[0106] 9. Automatic adjustment function for low pressure and low temperature

[0107] When the low-pressure switch protection action time is ≤10s, and the ambient temperature is ≤-10℃, the low-pressure switch delay will automatically adjust to 10s; when the ambient temperature is ≤-20℃, the low-pressure switch delay will automatically adjust to 30s; if the set value of the low-pressure switch protection action time is higher than 10s, the low-pressure switch delay will be determined according to the set value of the low-pressure switch protection action time; the display code for the low-pressure switch protection action time is F18.

[0108] Before high-pressure lockout, the high-pressure or low-pressure switch needs to detect continuous closure exceeding the condenser fan's delayed shutdown time before entering the reset state, and the compressor can only start after a minimum running time; the display code for the condenser fan's delayed shutdown time is F22; the main circuit solenoid valve and condenser fan start according to normal control logic; when high or low pressure protection is activated, the LED display digital tube outputs an alarm code, and the buzzer alarm does not activate.

[0109] 10. Power protection function

[0110] Power protection is only detected when the DIP switch is set to three-phase power; when the DIP switch is set to single-phase power, three-phase power protection is not detected. When the power status is a phase loss, phase loss protection is activated, and the compressor signal is disconnected. The phase power indicator LED display can directly display the phase loss through hardware. When the LED display outputs an alarm code, the buzzer also sounds an alarm. When the power status phase sequence is incorrect, phase sequence protection is activated, at which time the compressor signal is disconnected, the LED display outputs an alarm code, and the buzzer sounds an alarm. When phase imbalance is detected, phase imbalance protection is activated, at which time the compressor signal is disconnected, the LED display outputs an alarm code, and the buzzer sounds an alarm. When the power is detected to return to normal for 2 seconds, the alarm is reset, and the compressor, fan, and main circuit solenoid valve enter normal operation control. If a power error is detected three times consecutively during operation, the system will lock up and will not be restarted until power is cut off and reset. Here, error-to-normal constitutes one power error. In addition, when the power is locked up, the LED display outputs an alarm code, and the buzzer sounds an alarm.

[0111] 11. Compressor liquid slugging protection

[0112] When the third DIP switch is OFF, the compressor liquid slugging logic is not checked; when the third DIP switch is ON, the compressor liquid slugging logic is checked. The specific process for checking the compressor liquid slugging logic is as follows: when the real-time discharge temperature of the compressor drops by more than 20°C within 3 minutes, it is determined that the discharge temperature minus the condensing temperature is less than the liquid slugging protection trigger value. Simultaneously, if the real-time return gas temperature of the compressor is less than the preset return gas temperature, the liquid slugging protection is triggered. When the liquid slugging protection is triggered, the compressor shuts down, and the fault is automatically cleared after 3 minutes. At this time, the LED display digital tube outputs a fault code, and the buzzer alarm outputs an alarm. Preferably, the liquid slugging protection trigger value is 15°C by default.

[0113] In this embodiment, a compressor relay is used to respond to the compressor's start-stop control signal to control the compressor's start and stop; a solenoid valve relay is used to respond to the start-stop control signal of the main circuit refrigeration solenoid valve to control the main circuit refrigeration solenoid valve's start and stop; a liquid injection relay is used to respond to the start-stop control signal of the cooling liquid injection valve to control the cooling liquid injection valve's start and stop; the LED display digital tube uses light-emitting LEDs; wherein, all light-emitting LEDs are lit when the circuit is energized and are off when there is no power.

[0114] In the interactive module, pressing and holding the third interactive button for more than 3 seconds enters the setting state. After the LED display digital tube performs a power-on self-test, it rotates the static display of the compressor's real-time exhaust temperature, the condenser fan's real-time condensing temperature, and the compressor's real-time ambient temperature every 3 seconds by default. Specifically, it first displays the parameter code, then the data corresponding to the code, and then switches to the next parameter code. The display time for both the parameter code and the data is 3 seconds. Parameters are not displayed during faults. Fault codes flash at a frequency of 0.5 seconds. If multiple faults occur, each fault code is displayed twice and displayed in a loop. In the standby interface or during an alarm, pressing the value increment and value decrement keys in the interactive module allows viewing other parameters, including the compressor's real-time return gas temperature, the status of the liquid injection solenoid valve, and the opening of the electronic expansion valve. Viewing these parameters in this way does not involve a 3-second rotation. When the corresponding code is selected, press OK to view the immediate value, then press to return to the previous level, and press and hold to exit. By long-pressing the confirmation button, you can enter or exit the parameter query interface; in the parameter status query interface, pressing the confirmation button will take you to the parameter setting interface; in the parameter setting interface, you can set parameters using the value increment and value decrement buttons in the interactive module; you can save the settings by pressing the confirmation button; click the confirmation button again to confirm the settings; or after 30 seconds of no further operation, you can exit the setting state directly, and the settings will be invalid.

[0115] When the LED display digital tube shows parameters or fault codes, press and hold the confirmation button for 3 seconds to enter the parameter query interface. During this time, the parameter code is displayed for 2 seconds, and the parameter data is displayed for 2 seconds. In the parameter query interface, press the up or down keys to change the queried parameter code, and click the confirmation button to adjust the parameter. The parameter data flashes at a frequency of 0.5 seconds for 4 seconds, and the parameter code is displayed for 1 second. At this time, use the value increment and value decrement keys in the interactive module to modify the parameter. After modifying the parameter, click the confirmation button again to complete the modification. If there is no operation for 30 seconds while the parameter query interface is displayed, it will automatically exit the query interface. Note that if parameters are changed during setting but the confirmation button is not pressed, the modified parameters will not be saved.

[0116] In this embodiment, the logic control parameters set or adjusted by the interactive module can be programmed to add or change the content of the control parameters according to actual needs, as shown in Table 1.

[0117] Table 1. Settable or Adjustable Logic Control Parameters

[0118]

[0119]

[0120] It should be noted that the fault codes include: exhaust temperature sensor fault E01, condensate temperature sensor fault E02, ambient temperature sensor fault E03, return gas temperature sensor fault E04, high pressure switch fault E05, low pressure switch fault E06, reserved switch fault E07, exhaust temperature protection fault E08, condensate temperature protection fault E09, liquid hammer protection fault E10, phase loss fault E11, phase sequence error fault E12, phase imbalance fault E13, power supply error lockout fault E14i, and high pressure alarm lockout fault HP.

[0121] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A programmable control system for refrigeration and freezing units, characterized in that, It includes an interaction module, a detection module, and a control and protection module; the interaction module is used to set or adjust logic control parameters; the detection module is used to collect the operating parameters of the refrigeration unit; the control and protection module is used to control the operating status of the refrigeration unit based on the collected operating parameters of the refrigeration unit and in combination with the pre-set or adjusted logic control parameters. The detection module includes a temperature detection module, a power detection module, and a switch signal detection module; The temperature detection module is used to collect the real-time exhaust temperature of the compressor, the real-time condensing temperature of the condenser fan, and the real-time ambient temperature of the compressor. The power supply detection module is used to detect the power supply status of the compressor and obtain the power supply phase state detection result of the compressor; the switch signal detection module is used to detect the switching status of the on / off switch in the compressor and obtain the switching status signal of the on / off switch in the compressor. The control and protection module includes an exhaust protection module, a condenser fan control module, a solenoid valve / expansion valve control module, a crankshaft heating belt control module, a first start-stop control module, and a second start-stop control module. The exhaust protection module is used to protect the compressor from overheating based on the real-time exhaust temperature. The condenser fan control module is used to regulate and control the condenser fan based on the real-time condensing temperature. The solenoid valve / expansion valve control module is used to start / stop the liquid injection solenoid valve in the compressor or adjust the opening of the electronic expansion valve in the compressor based on the real-time exhaust temperature. The crankshaft heating belt control module is used to control the power supply to the crankcase heating belt in the compressor based on the real-time ambient temperature. The first start-stop control module is used to control the compressor to start or stop or protect it from abnormal shutdown based on the power phase state detection result of the compressor. The second start-stop control module is used to control the start-stop of the compressor and protect it from abnormal shutdown based on the on / off status signal of the on / off switch in the compressor.

2. The programmable control system for a refrigeration unit according to claim 1, characterized in that, The temperature detection module includes an exhaust temperature sensor, a condensation temperature sensor, and an ambient temperature sensor. The exhaust temperature sensor is used to collect the real-time exhaust temperature of the compressor; the condensing temperature sensor is used to collect the real-time condensing temperature of the condenser fan; and the ambient temperature sensor is used to collect the real-time ambient temperature of the compressor.

3. A programmable control system for a refrigeration unit according to claim 1, characterized in that, The switch signal detection module includes a high-pressure switch status detection module, a low-pressure switch status detection module, a 220V power-on signal detection module, and a passive switch status detection module. The high-pressure switch status detection module is used to detect the switching status of the high-pressure switch in the compressor and obtain the switching status signal of the high-pressure switch; the low-pressure switch status detection module is used to detect the switching status of the low-pressure switch in the compressor and obtain the switching status signal of the low-pressure switch; the 220V start-up signal detection module is used to acquire the 220V start-up signal of the compressor; and the passive switch status detection module is used to acquire the switching status signal of the passive switch in the compressor.

4. A programmable control system for a refrigeration unit according to claim 3, characterized in that, The second start-stop control module includes start-stop control unit A and start-stop control unit B; The start / stop control unit A is used to control the compressor to start / stop and protect it from abnormal shutdown based on the switch status signal of the high-pressure switch or the switch status signal of the low-pressure switch. The start / stop control unit B is used to control the compressor to start and stop based on the compressor's 220V start signal or the switch status signal of the passive switch in the compressor.

5. A programmable control system for a refrigeration unit according to claim 1, characterized in that, It also includes a display module; the display module is used to display the compressor's operating status parameters or fault codes.

6. A programmable control system for a refrigeration unit according to claim 1, characterized in that, The interactive module includes three interactive buttons: the first interactive button is an increment button, used to increase the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameter; the second interactive button is a decrement button, used to decrease the value of the parameter to be set by a preset step size when setting or adjusting the logic control parameter; and the third interactive button is a confirmation button, used to confirm that the current value of the parameter to be set is the new setting value when setting or adjusting the logic control parameter.

7. A programmable control system for a refrigeration unit according to claim 1, characterized in that, It also includes an alarm output module; the alarm output module is used to output fault alarm signals.

8. A programmable control system for a refrigeration unit according to claim 1, characterized in that, It also includes a DIP switch; the DIP switch is used to select the control mode.

9. A programmable control system for a refrigeration unit according to claim 1, characterized in that, It also includes a liquid hammer protection module; The temperature detection module is also used to collect the real-time return gas temperature of the compressor; The liquid slugging protection module is used to determine the liquid slugging state of the compressor based on the real-time exhaust temperature of the compressor, the real-time condensing temperature of the condenser fan, and the real-time return gas temperature of the compressor, and to perform liquid slugging protection control on the compressor based on the liquid slugging state determination result.

10. A programmable control method for refrigeration and freezing units, characterized in that, Using a programmable control system for refrigeration and cold storage units as described in any one of claims 1-9; The control method includes: The system collects real-time discharge temperature of the compressor, real-time condensing temperature of the condenser fan, and real-time ambient temperature of the compressor. The power supply status of the compressor is detected, and the power supply phase status detection results of the compressor are obtained; The on / off state of the on / off switch in the compressor is detected, and the on / off state signal of the on / off switch in the compressor is obtained; The compressor is protected against overheating based on its real-time exhaust temperature. The condenser fan is adjusted and controlled according to its real-time condensing temperature. Based on the real-time discharge temperature of the compressor, the start / stop control of the liquid injection solenoid valve in the compressor or the opening degree adjustment of the electronic expansion valve in the compressor are performed. The power supply to the crankcase heating belt in the compressor is controlled based on the real-time ambient temperature of the compressor. Based on the power phase state detection results of the compressor, start-up and shutdown control and abnormal shutdown protection of the compressor are implemented; Based on the on / off status signal of the on / off switch in the compressor, the compressor is controlled to start / stop and protected against abnormal shutdown.

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