A supermarket split type refrigerator controller and a control method thereof

Abstract

The application discloses a supermarket split type refrigerator controller and a control method, which is provided with six temperature signal input channels, which are respectively used for inputting air outlet temperature, return air temperature, first defrosting temperature, cabinet temperature, evaporator outlet temperature and second defrosting temperature signals to a main control board, and PID automatic adjustment of the opening degree and the change speed of the electronic expansion valve is adopted for the superheat control method of the electronic expansion method, so that the refrigeration system is truly in the best working state. In addition, the control mode can be divided into daytime and nighttime, precise control of the refrigerant electromagnetic valve is realized, frequent operation of the electromagnetic valve due to large temperature fluctuation in the cabinet is avoided, the service life of the electromagnetic valve is prolonged, and the use cost of the supermarket refrigerator is reduced. The application is provided with multiple channels, digital quantity input, upper computer cascade and remote communication through an IOT template can be realized, and quality monitoring is more stable and convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of refrigerator controller and control method, in particular to a kind of supermarket split type refrigerator controller and control method. BACKGROUND

[0002] Supermarket refrigerator is the refrigerator used for displaying goods in supermarket, and has built-in type and split type two structural forms.Supermarket split type refrigerator has cabinet and cabinet door, and is provided with refrigerator controller in cabinet, and evaporative fan, temperature control probe, refrigerant pipeline solenoid valve, lighting lamp, door magnetic switch installed between cabinet and cabinet door and the like connected with controller.And compressor, condenser and evaporator and other refrigeration systems are separated from cabinet, and refrigeration system is connected with multiple split type refrigerators through refrigerant pipeline.The existing refrigerator controller is sensed by temperature control probe arranged in cabinet, and when reaching the upper and lower limit of set temperature, corresponding opening or closing of refrigerant pipeline solenoid valve is controlled.But because of the difference in opening frequency of cabinet door in daytime (business hours) and night (non-business hours), the temperature signal sensed by temperature control probe in cabinet changes greatly, so that refrigerant pipeline solenoid valve frequently operates, directly affecting the service life of solenoid valve, and increasing the use cost of supermarket refrigerator.In addition, the superheat control method is used for electronic expansion valve, that is, the control of electronic expansion valve is realized by controlling the superheat degree (the difference between evaporator outlet temperature and evaporator outlet saturation temperature) of evaporator outlet.Specific method is that when superheat degree is higher than set value, the opening of electronic expansion valve is adjusted to control the flow of refrigerant, otherwise, the electronic expansion valve is not adjusted, and the original refrigerant flow is still maintained.However, the change speed and opening of electronic expansion valve of existing control method are not determined by PID control parameters, so that the refrigeration system cannot be truly in the best working state. SUMMARY

[0003] The present application is to solve the above technical problems existing in the prior art, and provides a kind of supermarket split type refrigerator controller and control method.

[0004] The technical solution of the present application is: a kind of supermarket split type refrigerator controller, which has printed circuit board, and the main control board and the following multiple channels connected with the main control board are integrated on the printed circuit board:

[0005] 6-way temperature signal input channel is used to input air outlet temperature, return air temperature, first defrosting temperature, cabinet temperature, evaporator outlet temperature and second defrosting temperature signal to the main control board respectively;

[0006] Pressure signal input channel is used to input evaporator outlet pressure signal to the main control board;

[0007] A night mode switch signal input channel for inputting a night mode switch state signal to the main control board;

[0008] A remote refrigeration control switch state signal input channel for inputting a remote refrigeration control switch state signal to the main control board;

[0009] A 2-way digital signal input channel for inputting a digital signal to the main control board;

[0010] A 2-way evaporative fan control signal output channel for outputting an instruction signal for controlling an evaporative fan;

[0011] A cabinet-outside lighting control signal output channel for outputting an instruction signal for controlling a cabinet-outside lighting lamp;

[0012] A cabinet-inside lighting control signal output channel for outputting an instruction signal for controlling a cabinet-inside lighting lamp;

[0013] An alarm signal output channel for outputting an instruction signal for controlling an alarm device;

[0014] A dimming control signal output channel for outputting an instruction signal for adjusting the brightness of a cabinet-inside lighting lamp;

[0015] A non-cold state feedback signal input channel for inputting a feedback signal that the compressor is in a non-cold state to the main control board;

[0016] A defrosting synchronization input / output channel for inputting a defrosting synchronization signal to the main control board or outputting a defrosting synchronization signal by the main board;

[0017] A defrosting relay control signal output channel for outputting an instruction signal for controlling a defroster;

[0018] A refrigeration control signal output channel for outputting a signal for controlling a refrigerant electromagnetic valve;

[0019] An electronic expansion valve control signal output channel for outputting a signal for controlling the opening degree of an electronic expansion valve;

[0020] A condensation-preventing solid-state relay regulating power output channel for outputting a low-voltage direct-current control signal for regulating a solid-state relay connected with a condensation-preventing heater;

[0021] An analog signal output channel for outputting a 0-10V / 4-20mA analog signal to control an EC energy-saving fan.

[0022] The preferred technical solution is that the main control board is connected with an IOT board through a communication interface circuit arranged on a printed circuit board.

[0023] The preferred technical solution is that the IOT template is an NB-IOT module, a LoRa module, a 4G module or a 5G module.

[0024] The preferred technical solution is that the IOT board communicates with a remote monitoring server, and the remote monitoring server communicates with a mobile / PC device through an Internet network.

[0025] A control method of the above-mentioned commercial super split type refrigerator controller, when there is a refrigeration request, outputting a signal for controlling the opening degree of the electronic expansion valve, that is, if the superheat is higher than the set value, the PID control increases the opening degree and the change speed of the electronic expansion valve; the control steps for the step type electronic expansion valve and the PWM type electronic expansion valve are as follows:

[0026] A. Step type electronic expansion valve

[0027] Initial power-on: first close the electronic expansion valve, ensure that the electronic expansion valve opening degree is zero, and the corresponding step number is zero;

[0028] At each time when refrigeration is needed: first open the electronic expansion valve to the initial opening degree and keep the time delay, and then perform PID automatic adjustment of the electronic expansion valve opening degree after the time delay ends;

[0029] When refrigeration is not needed: close the electronic expansion valve to the shutdown set position, and close the solenoid valve at the same time;

[0030] B. PWM type electronic expansion valve

[0031] At each time when refrigeration is needed: first open the electronic expansion valve to the initial opening degree and keep the time delay, and then perform PID automatic adjustment of the electronic expansion valve opening degree after the time delay ends;

[0032] When refrigeration is not needed: close the electronic expansion valve to the shutdown set position, and close the solenoid valve at the same time.

[0033] The preferred control method is to have a daytime mode and a nighttime mode, which are as follows:

[0034] Daytime mode: control the opening and closing of the refrigerant solenoid valve by detecting the return air temperature;

[0035] When the return air temperature is greater than or equal to the temperature set value and the temperature upper deviation value, open the refrigerant solenoid valve; when the return air temperature is less than or equal to the temperature set value, close the refrigerant solenoid valve;

[0036] Nighttime mode: control the opening and closing of the refrigerant solenoid valve by detecting the return air temperature

[0037] When the return air temperature is greater than or equal to the return air temperature set value, the return air temperature upper deviation, and the nighttime mode set value upper floating deviation, open the refrigerant solenoid valve; when the return air temperature is less than or equal to the return air temperature set value and the nighttime mode set value upper floating deviation, close the refrigerant solenoid valve.

[0038] The application sets 6 temperature signal input channels, respectively used for inputting the air outlet temperature, return air temperature, first defrosting temperature, cabinet temperature, evaporator outlet temperature and second defrosting temperature signals to the main control board, and for the superheat control method of electronic expansion method, the PID automatic adjustment electronic expansion valve opening degree and change speed are adopted, so that the refrigeration system is truly in the best working state. In addition, the control mode is divided into daytime and nighttime: the daytime mode is to control the opening and closing of the refrigerant electromagnetic valve by detecting the return air temperature; the nighttime mode is to control the opening and closing of the refrigerant electromagnetic valve by detecting the air outlet temperature. The precise control of the refrigerant electromagnetic valve can be realized, the frequent action of the electromagnetic valve due to the large cabinet temperature fluctuation is avoided, the service life of the electromagnetic valve is prolonged, and the use cost of the supermarket freezer is reduced. The application sets multiple channels, can realize digital quantity input, host computer cascade and remote communication through IOT template, and the quality monitoring is more convenient. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the embodiment of the application. DETAILED DESCRIPTION

[0040] The application is a controller of a supermarket split type freezer, the structure of the supermarket split type freezer is the same as that of the prior art, the refrigeration system is connected with multiple split type freezers through a refrigerant pipeline, one master cabinet and multiple slave cabinets are included in the multiple split type freezers, and the controllers of the master cabinet and the slave cabinets are as shown in the figure. Figure 1 There is a printed circuit board, the printed circuit board is integrated with a main control board (MCU) and a communication interface circuit connected with the main control board, an RS485 communication interface circuit, a display interface circuit and a power input circuit, the RS485 communication interface circuit supports Modbus communication protocol, can realize data networking communication and host computer cascade, the display interface circuit is used for connecting with a display, the display has a separate shell installation, includes an LED display unit, is used for displaying LOGO, temperature, humidity, energy consumption, time, setting and working state etc.; includes 7 touch keys, is used for interactive input; a built-in buzzer is used for alarm prompt etc.

[0041] The printed circuit board is also integrated with the following multiple channels connected with the main control board:

[0042] 6 temperature signal input channels, respectively used for inputting the air outlet temperature, return air temperature, first defrosting temperature, cabinet temperature, evaporator outlet temperature and second defrosting temperature signals to the main control board;

[0043] A pressure signal input channel is used for inputting the evaporator outlet pressure signal to the main control board, that is, a pressure sensor is arranged at the evaporator outlet, and the pressure signal detected by the pressure sensor is input to the main control board from this channel;

[0044] Night mode switch signal input channel, for inputting night mode switch state signal to main control board;

[0045] Remote refrigeration control switch state signal input channel, for inputting remote refrigeration control switch state signal to main control board, the remote refrigeration control switch is a switch for remotely controlling the compressor to refrigerate or not to refrigerate;

[0046] 2-way digital signal input channel, for inputting digital signal to main control board, which can be set to select external alarm, door switch, door curtain switch and other digital signals;

[0047] 2-way evaporative fan control signal output channel, for outputting control signal of evaporative fan, one way is control signal of evaporative fan switch, and the other way is signal of evaporative fan speed control;

[0048] Cabinet outside lighting control signal output channel, for outputting control signal of cabinet outside lighting lamp, which is turned off during the day and turned on at night;

[0049] Cabinet inside lighting control signal output channel, for outputting control signal of cabinet inside lighting lamp, which is controlled by main control board according to cabinet door switch state, and controls electric plug lock and lighting lamp;

[0050] Alarm signal output channel, for outputting control signal of alarm device;

[0051] Dimming control signal output channel, for outputting control signal of adjusting brightness of cabinet inside lighting lamp;

[0052] Non-refrigeration state feedback signal input channel, for inputting feedback signal of compressor in non-refrigeration state to main control board;

[0053] Defrosting synchronization input / output channel, for inputting defrosting synchronization signal to main control board or outputting defrosting synchronization signal by main board; if the controller is a master cabinet, this channel is used for outputting defrosting synchronization signal, and if the controller is a slave cabinet, this channel is used for inputting defrosting synchronization signal to main control board;

[0054] Defrosting relay control signal output channel, for outputting control signal of defroster;

[0055] Refrigeration control signal output channel, for outputting signal of controlling refrigerant electromagnetic valve;

[0056] Electronic expansion valve control signal output channel, for outputting signal of controlling opening degree of electronic expansion valve;

[0057] Anti-condensation solid-state relay regulating power output channel, for outputting low-voltage direct-current control signal of regulating solid-state relay connected with anti-condensation heater;

[0058] Analog output reserved channel is used for outputting 0-10V / 4-20mA analog signal to control EC energy-saving fan.

[0059] The main control board is connected with the IOT board through a communication interface circuit arranged on the printed circuit board, the IOT template can be an NB-IOT module, a LoRa module, a 4G module or a 5G module, the IOT board communicates with a remote monitoring server, and the remote monitoring server communicates with a mobile / PC device end through an Internet network.

[0060] The control method of the above supermarket split type refrigerator controller is that when there is a refrigeration request (the electromagnetic valve relay is enabled), a signal for controlling the opening degree of the electronic expansion valve is output, that is, if the superheat degree is higher than the set value, the PID control increases the opening degree and the change speed of the electronic expansion valve; the control steps of the step-type electronic expansion valve and the PWM-type electronic expansion valve are as follows:

[0061] A. Step-type electronic expansion valve

[0062] When initially powered on: first, close the electronic expansion valve to ensure that the opening degree of the electronic expansion valve is zero, and the corresponding step number is zero;

[0063] When refrigeration is needed each time (normal working refrigeration and refrigeration needed after defrosting is finished): first, open the electronic expansion valve to the initial opening degree and keep a time delay, and then automatically adjust the opening degree of the electronic expansion valve by PID after the time delay is over;

[0064] When refrigeration is not needed: close the electronic expansion valve to the shutdown set position, and close the electromagnetic valve at the same time.

[0065] B. PWM-type electronic expansion valve

[0066] When refrigeration is needed each time (normal working refrigeration and refrigeration needed after defrosting is finished): first, open the electronic expansion valve to the initial opening degree and keep a time delay, and then automatically adjust the opening degree of the electronic expansion valve by PID after the time delay is over;

[0067] When refrigeration is not needed: close the electronic expansion valve to the shutdown set position, and close the electromagnetic valve at the same time.

[0068] The preferred control method is divided into daytime mode and night mode, and the specific steps are as follows:

[0069] Daytime mode: the opening and closing of the refrigerant electromagnetic valve are controlled by detecting the return air temperature;

[0070] When the return air temperature is greater than or equal to the temperature set value and the temperature upper deviation value, the refrigerant electromagnetic valve is turned on; when the return air temperature is less than or equal to the temperature set value, the refrigerant electromagnetic valve is turned off;

[0071] Night mode: the opening and closing of the refrigerant electromagnetic valve are controlled by detecting the outlet air temperature

[0072] When the outlet air temperature is greater than or equal to the sum of the return air temperature set value, the return air temperature upper deviation, and the night mode set value upper floating deviation, the refrigerant solenoid valve is opened. When the outlet air temperature is less than or equal to the sum of the return air temperature set value and the night mode set value upper floating deviation, the refrigerant solenoid valve is closed.

Claims

1. A control method for a supermarket split-type refrigerator controller, characterized by: When there is a cooling request, a signal to control the opening of the electronic expansion valve is output. That is, if the superheat is higher than the set value, the PID control increases the opening of the electronic expansion valve and the speed of change. The control steps for the stepping electronic expansion valve and the PWM electronic expansion valve are as follows: A. Step-type electronic expansion valve When initially powered on: first close the electronic expansion valve to ensure that when the opening of the electronic expansion valve is zero, the corresponding number of steps is zero; Each time cooling is required: first open the electronic expansion valve to the initial opening and maintain the time delay. After the time delay ends, PID automatically adjusts the opening of the electronic expansion valve. When cooling is not required: close the electronic expansion valve to the shutdown setting position and close the solenoid valve at the same time; B. PWM electronic expansion valve Each time cooling is required: first open the electronic expansion valve to the initial opening and maintain the time delay. After the time delay ends, PID automatically adjusts the opening of the electronic expansion valve. When cooling is not required: close the electronic expansion valve to the shutdown setting position and close the solenoid valve at the same time; There are day mode and night mode, as follows: Day mode: Control the opening and closing of the refrigerant solenoid valve by detecting the return air temperature; When the return air temperature is greater than or equal to the temperature setting value and the temperature upper deviation value, the refrigerant solenoid valve is opened; when the return air temperature is less than or equal to the temperature setting value, the refrigerant solenoid valve is closed; Night mode: Control the opening and closing of the refrigerant solenoid valve by detecting the outlet air temperature When the outlet air temperature is greater than or equal to the sum of the return air temperature setting value, the return air temperature upper deviation and the night mode setting value upper deviation, the refrigerant solenoid valve is opened; when the outlet air temperature is less than or equal to the return air temperature setting value and the night mode setting value upper deviation, the refrigerant solenoid valve is closed.

2. The control method of the supermarket split-type refrigerator controller according to claim 1, characterized in that: The supermarket split-type refrigerator controller has a printed circuit board, which integrates a main control board and a communication interface circuit connected to the main control board, an RS485 communication interface circuit, a display interface circuit, and a power input circuit. The printed circuit board also integrates the following multiple channels connected to the main control board: 6 temperature signal input channels, used to input the outlet air temperature, return air temperature, first defrost temperature, cabinet temperature, evaporator outlet temperature and second defrost temperature signals to the main control board; Pressure signal input channel, used to input evaporator outlet pressure signal to the main control board; Night mode switch signal input channel, used to input the night mode switch status signal to the main control board; Remote refrigeration control switch status signal input channel, used to input remote refrigeration control switch status signal to the main control board; 2-way digital signal input channels, used to input digital signals to the main control board; 2-way evaporation fan control signal output channel, used to output the command signal for controlling the evaporation fan; External lighting control signal output channel, used to output command signals for controlling external lighting; The cabinet lighting control signal output channel is used to output the command signal for controlling the lighting in the cabinet; Alarm signal output channel, used to output command signals for controlling the alarm device; Dimming control signal output channel, used to output the command signal for adjusting the brightness of the lighting in the cabinet; The non-cooling state feedback signal input channel is used to input the feedback signal that the compressor is in the non-cooling state to the main control board; Defrost synchronization input and output channel, used to input defrost synchronization signal to the main control board or output defrost synchronization signal from the main board; Defrost relay control signal output channel, used to output the command signal for controlling the defroster; Refrigeration control signal output channel, used to output the signal for controlling the refrigerant solenoid valve; Electronic expansion valve control signal output channel, used to output the signal for controlling the opening of the electronic expansion valve; The anti-condensation solid-state relay regulates the power output channel, which is used to output a low-voltage DC control signal for regulating the solid-state relay connected to the anti-condensation heater; Analog signal output channel, used to output 0-10V / 4-20mA analog signal to control EC energy-saving fans.

3. The control method of the supermarket split-type refrigerator controller according to claim 2, characterized in that: The main control board is connected to the IOT board via a communication interface circuit arranged on the printed circuit board.

4. The control method of the supermarket split-type refrigerator controller according to claim 3, characterized in that: The IOT board is an NB-IOT module, a LoRa module, a 4G module or a 5G module.

5. The supermarket split-type refrigerator controller according to claim 4, characterized in that: The IOT board communicates with the remote monitoring server, and the remote monitoring server communicates with the mobile / PC device end through the Internet network.

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