Control board card for temperature control system and compressor circulating refrigeration system

Abstract

The invention belongs to the field of temperature control equipment, and particularly discloses a control board card for a temperature control system and a compressor circulating refrigeration system, and the temperature control system comprises a working device, an electric valve, a pressure sensor and a temperature sensor; the control board card comprises a substrate, and an analog quantity acquisition module, a communication module, a main control module and a valve driving module which are integrated on the substrate; the analog quantity acquisition module is used for acquiring pressure sensor data; the communication module is used for acquiring data of the temperature sensor and realizing communication between the main control module and the outside; the main control module is connected with the analog quantity acquisition module, the communication module and the valve driving module, and the main control module is used for determining the target opening degree of the electric valve according to the pressure sensor data and the temperature sensor data and controlling the opening degree of the electric valve through the valve driving module according to the target opening degree. According to the invention, a driver or other functional hardware can be prevented from being added in the circuit during temperature control, the equipment cost is reduced, and the control logic is simplified.

Description

Technical Field

[0001] The present invention belongs to the field of temperature control equipment, and more specifically, relates to a control board for a temperature control system and a compressor cycle refrigeration system. Background Art

[0002] Existing temperature controllers generally implement data monitoring and control of a compressor cycle refrigeration system based on a PLC, and use general discrete boards or modules in combination; for example, using a PLC as the main controller, and combining a power supply board, an analog acquisition board, a communication board, etc. to form a control circuit to achieve data monitoring and control.

[0003] However, the combined use of multiple discrete hardware modules will result in complex hardware control logic, and there are problems such as bloated volume, complex wiring, and high cost. Summary of the Invention

[0004] In view of the above defects or improvement requirements of the prior art, the present invention provides a control board for a temperature control system and a compressor cycle refrigeration system, aiming to reduce the equipment cost, volume, and simplify the control logic during temperature control of the temperature control system.

[0005] To achieve the above object, according to one aspect of the present invention, a control board for a temperature control system is proposed. The temperature control system includes a working device, an electric valve, a pressure sensor, and a temperature sensor, wherein the working device is used to adjust the temperature, the electric valve is used to control the flow rate of the working device, and the pressure sensor and the temperature sensor are respectively used to collect the working pressure and temperature;

[0006] The control board includes a substrate and an analog acquisition module, a communication module, a main control module, and a valve drive module integrated on the substrate;

[0007] The analog acquisition module is used to obtain the pressure sensor data;

[0008] The communication module is used to obtain the temperature sensor data and realize communication between the main control module and the outside world;

[0009] The main control module is connected to the analog acquisition module, the communication module, and the valve drive module. The main control module is used to determine the target opening of the electric valve according to the pressure sensor data and the temperature sensor data, and control the opening of the electric valve through the valve drive module according to the target opening.

[0010] As a further preference, the ground plane of the analog acquisition module circuit is isolated from the digital ground plane inside the control board by a 0-ohm resistor.

[0011] As a further preference, the analog quantity acquisition module includes a first resistor, an active amplification circuit, and an active second-order low-pass filter circuit. Among them, the first resistor is used to convert the current signal of the pressure sensor into a voltage signal, the active amplification circuit is used to amplify the voltage signal, and the active second-order low-pass filter circuit is used to output the amplified voltage signal to the main control module.

[0012] As a further preference, the communication module includes an isolated RS485 communication chip and a TVS tube array. The isolated RS485 communication chip is connected to the main control module, and the TVS tube array is connected in parallel with the differential signal lines of the isolated RS485 communication chip.

[0013] As a further preference, it further includes a digital quantity acquisition module and a digital quantity output module, both of which are connected to the main control module; the digital quantity acquisition module is used to obtain the digital quantity of the temperature control system and transmit it to the main control module; the digital quantity output module is used to adjust the digital quantity of the temperature control system according to the instructions of the main control module.

[0014] As a further preference, the digital quantity acquisition module includes a parallel-connected resistor voltage division circuit and an optocoupler isolation chip. The resistor voltage division circuit is used to divide the digital quantity collected and supply it to the optocoupler isolation chip, and the optocoupler isolation chip is used to output the divided digital quantity to the main control module;

[0015] The digital quantity output module includes a high-current digital quantity output circuit and a low-current digital quantity output circuit; the high-current digital quantity output circuit includes a triode switch, an optocoupler isolation chip, an NMOS transistor, and a freewheeling diode. The triode switch is connected to the main control module and is connected in series with the input stage of the optocoupler isolation chip. The output stage of the optocoupler isolation chip is connected in parallel with the NMOS transistor, and the freewheeling diode is reversely connected in parallel with the D pole of the NMOS transistor; the low-current digital quantity output circuit includes a Darlington pair integrated chip, and this Darlington pair integrated chip is connected to the main control module.

[0016] As a further preference, it further includes a power supply module, which is used to supply power to the analog quantity acquisition module, the communication module, the main control module, the valve drive module, the digital quantity acquisition module, and the digital quantity output module.

[0017] As a further preference, the power supply module adopts a four-stage circuit conversion architecture, including a 24V power input protection circuit, a 24V to 12V DCDC circuit, a 12V to 5V DCDC circuit, and a 5V to 3.3V LDO circuit; the 24V power input protection circuit is used to provide 24V working power for the digital input module and the digital output module, the 24V to 12V DCDC circuit is used to provide 12V working power for the valve drive module, the 12V to 5V DCDC circuit is used to provide 5V working power for the analog input module and the communication module, and the 5V to 3.3V LDO circuit is used to provide 3.3V working power for the main control module.

[0018] As a further preference, the power supply module supplies power to the communication module via an RS485 isolated power supply circuit, and the RS485 isolated power supply circuit includes an isolated power supply chip and a capacitor connected in parallel with the isolated power supply chip.

[0019] According to another aspect of the present invention, there is provided a compressor cycle refrigeration system, which uses the above control board for the temperature control system to perform temperature control.

[0020] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, the following technical advantages are mainly possessed:

[0021] 1. The control board of the present invention integrates the analog input module, the communication module, the main control module and the valve drive module, and a single board can complete data acquisition, algorithm operation and output control, avoiding the addition of extra drivers and transmitters in the controller of the temperature control system, reducing the cost and volume of the equipment, and simplifying the control logic at the same time. An intelligent power-supply - acquisition - control - communication integrated platform can be established to meet the integrated, miniaturized and highly reliable requirements of industrial automation equipment for the control terminal.

[0022] 2. The present invention preferably isolates the analog circuit part and the digital circuit part by the ground plane isolation method, reducing the interference of digital signals to analog signals; and through the isolated power supply and the isolated RS485 chip, complete isolation between the communication interface and the internal circuit of the board is achieved, which can reduce the interference between modules after integration and avoid electromagnetic compatibility problems.

[0023] 3. The power supply module of the present invention preferably adopts a four-stage circuit conversion architecture, which can directly provide working power of different voltages for different modules, improving the power supply stability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the control board for the temperature control system according to the embodiment of the present invention;

[0025] Figure 2 Schematic diagram of the structure of the compression cycle refrigeration system according to an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the connection between the control board and the compression cycle refrigeration system according to an embodiment of the present invention;

[0027] Figure 4 Flow chart of a refrigeration cycle of the compressor cycle refrigeration system according to an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the structure of the power supply module according to an embodiment of the present invention;

[0029] Figure 6a Circuit diagram of the 24V power input protection according to an embodiment of the present invention;

[0030] Figure 6b Circuit diagram of the 24V to 12V DC-DC according to an embodiment of the present invention;

[0031] Figure 6c Circuit diagram of the 12V to 5V DC-DC according to an embodiment of the present invention;

[0032] Figure 6d Circuit diagram of the 5V to 3.3V LDO according to an embodiment of the present invention;

[0033] Figure 6e Circuit diagram of the RS485 isolated power supply according to an embodiment of the present invention;

[0034] Figure 7 Partial circuit diagram of the analog quantity acquisition module according to an embodiment of the present invention;

[0035] Figure 8 Partial circuit diagram of the digital quantity acquisition module according to an embodiment of the present invention;

[0036] Figure 9 Circuit diagram of the small current digital quantity output of the digital quantity output module according to an embodiment of the present invention;

[0037] Figure 10 Partial circuit diagram of the large current digital quantity output circuit of the digital quantity output module according to an embodiment of the present invention;

[0038] Figure 11 Circuit diagram of the valve drive module according to an embodiment of the present invention;

[0039] Figure 12 Circuit diagram of the RS485 communication module according to an embodiment of the present invention;

[0040] Figure 13 Circuit diagram of the main control module according to an embodiment of the present invention;

[0041] Figure 14Schematic diagram of the analog ground and digital ground isolation circuit according to an embodiment of the present invention. Detailed implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present 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 only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] A control board for a temperature control system provided by an embodiment of the present invention; the temperature control system includes a working device, an electric valve, a pressure sensor, and a temperature sensor. The working device is used to adjust the temperature; the electric valve is used to control the flow rate of the working medium in the working device, and specifically can be an electronic expansion valve, a direct-acting stepping motor-driven valve, etc.; the pressure sensor and the temperature sensor are respectively used to collect the pressure and temperature during operation. The temperature control system can specifically be a compressor cycle refrigeration system, an air-cooled temperature control system, a high and low temperature cycle system, etc.

[0044] The control board is used to control the temperature control system, such as Figure 1 shown, the control board includes a substrate and a power module, a main control module, an analog quantity acquisition module, a communication module, a valve drive module, a digital quantity acquisition module, and a digital quantity output module integrated on the substrate.

[0045] The power module is designed with a four-stage circuit conversion architecture of 24V→12V→5V→3.3V, and is combined with a distributed filter network and power plane isolation for digital / analog / communication circuits, solving the problem of large power and signal interference caused by electromagnetic compatibility; and integrating multiple protection functions such as overcurrent, overvoltage, reverse connection prevention, and surge protection to ensure the stability and safety of the power supply. The power module includes a 24V power input protection circuit, a 24V to 12V DCDC circuit, a 12V to 5V DCDC circuit, and a 5V to 3.3V LDO circuit; among them, as Figure 5 shown, the 24V power input protection circuit is used to provide 24V working power for the digital quantity acquisition module and the digital quantity output module, the 24V to 12V DCDC circuit is used to provide 12V working power for the valve drive module, the 12V to 5V DCDC circuit is used to provide 5V working power for the analog quantity acquisition module and the communication module, and the 5V to 3.3V LDO circuit is used to provide 3.3V working power for the main control module.

[0046] Specifically, the 24V power input protection circuit is as Figure 6aAs shown, it plays a role in protecting the power input, preventing power voltage surges, reverse power connection, and overcurrent. At the same time, the parallel distributed capacitance plays a certain filtering role. The power is input through the DC1 interface, DC—IN is the positive power supply, and GND1 and GND2 are connected to the GND pole of the power supply. U2 is a PMOS, which is connected in series with the power interface DC1 to act as a switching tube. It conducts only when the power supply is connected correctly and turns off when reversed, preventing reverse connection. The self-resetting fuse F1 is connected in series between DC1 and U2 to prevent overcurrent. The bidirectional transient diode D1 is connected in parallel with U2 to function as transient surge suppression, and bypasses the power supply when reversed to prevent reverse connection. The resistors R2 and R7 are connected in series for voltage division to keep the PMOS in the normal conducting state. The capacitors C1, C2, C3, C4, and C96 are connected in parallel to play a role in energy storage and filtering.

[0047] The 24V to 12V DCDC circuit is as Figure 6b shown. It mainly uses the DCDCC chip U30 in cooperation with the discrete inductor L4 and the switching tube D15 to convert the input voltage of 24V into an output of 12V. The discrete capacitors C103, C104, C105, C106, C07, C108, and C109 play a filtering role.

[0048] The 12V to 5V DCDC circuit is as Figure 6c shown. It mainly uses the DCDCC chip U9 in cooperation with the discrete inductor L4 and the switching tube D15 to convert the input voltage of 12V into an output of 5V. The discrete capacitors C26, C110, C27, C28, C102, C97, and C29 play a filtering role.

[0049] The 5V to 3.3V LDO circuit is as Figure 6d shown. The LDO chip U7 is used to convert the 5V input voltage into a 3.3V voltage. The discrete capacitors C23, C101, C24, and C99 are used in combination to play a filtering role.

[0050] Furthermore, the power supply module also includes an RS485 isolated power supply circuit. The 12V to 5V DCDC circuit supplies power to the communication module via the RS485 isolated power supply circuit. Specifically, the RS485 isolated power supply circuit is as Figure 6e shown. It realizes the isolation of the input 5V and output 5V power supplies and the isolation of the input ground plane and output ground plane through the isolation power supply chip U8 in combination with the capacitor C34. The discrete capacitors C30, C31, C32, and C33 are connected in parallel with the chip U8, and the inductor L2 is connected in series with the chip U8 to form a filtering network.

[0051] The main control module is the brain of the entire board, responsible for processing the collected data, performing algorithm operations for calculation and output, communication interaction, etc. The main control module is connected to the analog quantity acquisition module, RS485 communication module, valve drive module, digital quantity acquisition module, and digital quantity output module. The main control module chip uses an MCU of the STM32H7 series with an arm architecture.

[0052] Specifically, the main control module is as Figure 13 shown. In order to ensure the stable power supply of the ADC peripheral of the MCU to achieve high-precision acquisition of analog quantities, an array composed of magnetic beads and capacitors is used to isolate and filter the power supply of the ADC peripheral of the MCU, ensuring stable power supply to the analog power pins of the MCU; the magnetic beads absorb the spike pulses of the power supply, and the discrete capacitors eliminate the ripples.

[0053] The analog quantity acquisition module is used to obtain the data of the pressure sensor, and it converts the 4-20mA analog quantity collected by the sensor into a voltage analog quantity and outputs it to the main control MCU. The analog quantity acquisition module includes a high-precision resistor, a 10-fold active amplification circuit, and an active second-order low-pass filter circuit. Among them, the high-precision resistor is in parallel with the 10-fold active amplification circuit, and the 10-fold active amplification circuit is in series with the active second-order low-pass circuit. The high-precision resistor converts the collected current analog quantity into a voltage analog quantity, the 10-fold active amplification circuit amplifies the voltage signal, and the active second-order low-pass filter circuit outputs the amplified voltage signal to the main control MCU.

[0054] Specifically, the circuit of the analog quantity acquisition module is as Figure 7 shown. CN3 is the interface of the 24V transmitter. Port 1 can supply 24V DC power to the transmitter, and the 4-20mA loop current analog quantity of the transmitter is input to the board through Port 2. The 4-20mA current analog quantity flows through a precision resistor with a resistance accuracy of ±0.1% to be converted into a voltage analog quantity. The operational amplifier U15 and the peripheral discrete resistors R42, R46, R49, and R50 form a differential amplification circuit to amplify the analog quantity. The operational amplifier U16 and the peripheral discrete resistors R47, R48, and capacitors C60, C69 form a second-order low-pass active filter.

[0055] Furthermore, as Figure 14 shown, the analog circuit part (i.e., the analog quantity acquisition module) and the digital circuit part (other modules) are isolated through the ground plane isolation technology to reduce the interference of digital signals on analog signals. Specifically, the ground plane of the analog quantity acquisition module circuit is isolated from the digital ground plane inside the board through the 0-ohm resistor R1.

[0056] The communication module serves as a bridge for the main control MCU to communicate with the outside world and can obtain temperature sensor data. The communication module includes an isolated RS485 communication chip, a TVS tube array, and two self - reset fuses. The main control MCU is connected to the isolated RS485 communication chip, and the TVS tube array is connected in parallel with the differential signal lines of the RS485 communication chip. The main control MCU can send the parameters of each refrigeration cycle to the host computer through the RS485 communication module to display the data. The power supply module supplies power to the communication module through the RS485 isolation power supply circuit. Through the isolated power supply and the isolated RS485 chip, complete isolation between the communication interface and the internal circuit of the board is achieved, and over - voltage and over - current protection are realized through the TVS and self - reset fuses.

[0057] Specifically, the circuit of the communication module is as Figure 12 shown. With the isolated RS485 communication chip U24 as the core, a voltage isolation of up to ±16 kV is achieved. The resistor R76 functions as a matching resistor. The array composed of TVS tubes D12, D13, and D14 can prevent over - voltage on the communication wire. The self - reset fuses F4 and F5 play a role in over - current protection of the communication wire. The board communicates with the outside world through the interface CN19.

[0058] The valve drive module is connected to the TIM peripheral and GPIO peripheral of the main control MCU to drive a stepper - motor - type valve; the DRV8825 chip is adopted, and the use of the PWM output of the MCU simplifies the design of the drive circuit of the electric valve, improving the drive efficiency and reliability. Specifically, the main control module can determine the target opening of the electric valve according to the pressure sensor data and temperature sensor data, and control the opening of the electric valve through the valve drive module according to the target opening.

[0059] Specifically, the circuit of the valve drive module is as Figure 11 shown. The stepper - motor drive chip U4 can control the action of the electric valve through the cooperation of the TIM timer of the MCU and the GPIO of the MCU. The capacitors C13, C14, and C8 play a filtering role.

[0060] The digital input module converts the collected 24V digital input into a 3.3V level and outputs it to the main control MCU. The digital input module includes a resistor voltage - dividing circuit and an opto - isolator chip. The resistor voltage - dividing network is connected in parallel with the opto - isolation circuit, dividing the collected digital input voltage for the opto - isolator chip, and the opto - isolator chip outputs 3.3V to the main control MCU.

[0061] Specifically, part of the circuit of the digital input module is as Figure 8As shown, this part of the circuit can achieve the acquisition of 4 channels of 24V digital signals; resistors R77, R80, and R83 are connected in series for voltage division. The input stage of the optocoupler isolation chip U25 is connected in parallel with resistor R80 among them to obtain an appropriate input voltage. When the output stage is conducting, it injects a 3.3V voltage signal into the EXTI pin of the MCU to achieve high-sensitivity and high-precision digital signal sampling, and at the same time realizes the function of isolation protection. The zener diode ZD5 and capacitor C82 achieve the functions of voltage regulation and filtering.

[0062] The digital output module converts the 3.3V level output by the main control MCU into a 24V digital output. The digital output module includes two sub-modules: a high-current (>0.4A) digital output circuit and a low-current (≤0.4A) digital output circuit. The high-current digital output circuit includes a transistor switch, an optocoupler isolation chip, an NMOS transistor, and a freewheeling diode. The transistor is connected in series with the input stage of the optocoupler isolation chip. The output stage of the optocoupler isolation chip is connected in parallel with the NMOS transistor. The freewheeling diode is reversely connected in parallel at the D pole of the NMOS transistor. The GPIO output pin of the main control MCU is connected to the base of the transistor switch. When the GPIO pin outputs a high level, the transistor switch, the optocoupler isolation chip, and the NMOS transistor are all conducting, and a 24V digital signal is output. The low-current digital output circuit is a Darlington pair integrated chip. The GPIO of the main control MCU is directly connected to this chip. When the GPIO pin outputs a high level, the Darlington pair integrated chip is conducting, and a 24V digital signal is output.

[0063] Specifically, the high-current digital output circuit is as Figure 10 shown. The switch transistor Q2 is driven by the GPIO of the MCU, and then the optocoupler isolation chip U29 is driven, and further the NMOS transistor Q1 is driven to achieve the output of a high-current digital signal with 3.3V controlling 24V. The interface CN1 is connected to the electrical appliance that requires digital control. The freewheeling diode D5 can achieve the function of discharging the energy during power-off and preventing the internal circuit from being burned when CN1 is connected to an inductive load. The low-current digital output circuit is as Figure 9 shown. It mainly uses the Darlington pair chip Q12 as the switch, which is directly controlled by the GPIO of the MCU to achieve the output of a low-current 24V digital signal. The interfaces P13 and P14 can achieve the digital control of 7 channels.

[0064] The above control board can complete the data acquisition - algorithm processing - output control of the entire temperature control system, solving the problems that the existing control system based on PLC design has high complexity of the control circuit and complex control logic due to the need for additional drivers and hardware.

[0065] This embodiment is specifically described by taking the compressor cycle refrigeration system as an example. As Figure 2As shown in the figure, in the compressor cycle refrigeration system, the compressor is the core component of the refrigeration system, which compresses the low-temperature and low-pressure gaseous refrigerant into a high-temperature and high-pressure gaseous refrigerant. The refrigeration capacity can be controlled by controlling the rotational speed of the compressor. The condenser is a heat exchanger in the refrigeration system, which is responsible for cooling and liquefying the incoming high-temperature and high-pressure gaseous refrigerant. The electronic expansion valve is a throttling device in the system, which is responsible for throttling and reducing the pressure of the high-temperature and high-pressure liquid refrigerant. The evaporator is another heat exchanger in the system, where the refrigerant vaporizes and absorbs heat to achieve the refrigeration effect. The temperature sensor and pressure sensor respectively detect the temperature and pressure at the outlet of the compressor and the inlet and outlet of the evaporator. The temperature control system determines the compressor frequency corresponding to the required refrigeration capacity according to the deviation between the set temperature and the actual temperature at the outlet of the evaporator, and controls the compressor to operate at the target frequency to adjust the superheat at the outlet of the evaporator. In this process, the evaporator indirectly realizes the adjustment of the gas temperature by exchanging temperature with the outside air.

[0066] The control board is applied to the refrigeration system, and the connection relationship is as Figure 3 shown; Figure 4 The process of a refrigeration cycle for the refrigeration system connected to the control board includes the following steps:

[0067] The power module distributes the external power supply to each functional module inside the board;

[0068] The analog acquisition module acquires the current outputs of the pressure sensors P1, P2, and P3 with current-type analog outputs, converts them into voltage values, amplifies and filters them, and then inputs them to the main control module MCU;

[0069] The ADC peripheral of the MCU performs analog-to-digital conversion to obtain the data of the pressure sensors;

[0070] The MCU acquires the temperature data of the temperature sensors T1, T2, and T3 through the module to obtain the temperature values;

[0071] The MCU judges whether the pressure value and temperature value are abnormal according to the rules. When there is an abnormality, error handling is performed. If there is no abnormality, the process continues;

[0072] The MCU calculates the superheat SH based on the pressure P1 and temperature T1 at the outlet of the evaporator, and calculates the deviation e from the target superheat; calculates the target opening of the electronic expansion valve through the PID controller, and the MCU adjusts the opening of the electronic expansion valve through the valve drive module;

[0073] The MCU sends the parameters of this refrigeration cycle to the upper computer through the communication module, and one refrigeration cycle ends, and it is ready to enter the next refrigeration cycle.

[0074] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control board for a temperature control system, the temperature control system includes a working device, an electric valve, a pressure sensor and a temperature sensor, wherein: The working device is used to adjust the temperature, the electric valve is used to control the flow of the working device, and the pressure sensor and the temperature sensor are used to collect the working pressure and temperature respectively; the characteristics are: The control board includes a base plate and an analog quantity acquisition module, a communication module, a main control module and a valve drive module integrated on the base plate; The analog quantity acquisition module is used to obtain pressure sensor data; The communication module is used to obtain temperature sensor data and realize communication between the main control module and the outside world; The main control module is connected to the analog quantity acquisition module, the communication module and the valve drive module. The main control module is used to determine the target opening of the electric valve according to the pressure sensor data and the temperature sensor data, and control the opening of the electric valve through the valve drive module according to the target opening.

2. The control board for the temperature control system according to claim 1, characterized in that: The ground plane of the analog quantity acquisition module circuit is isolated from the digital ground plane inside the control board by a 0 ohm resistor.

3. The control board for the temperature control system according to claim 1, characterized in that: The analog quantity acquisition module includes a first resistor, an active amplifier circuit and an active second-order low-pass filter circuit, wherein the first resistor is used to convert the current signal of the pressure sensor into a voltage signal, the active amplifier circuit is used to amplify the voltage signal, and the active second-order low-pass filter circuit is used to output the amplified voltage signal to the main control module.

4. The control board for a temperature control system according to claim 1, characterized in that: The communication module comprises an isolated RS485 communication chip and a TVS tube array, the isolated RS485 communication chip is connected to the main control module, and the TVS tube array is connected in parallel with the differential signal line of the isolated RS485 communication chip.

5. The control board for a temperature control system according to any one of claims 1 to 4, characterized in that: It also includes a switch quantity acquisition module and a switch quantity output module, both of which are connected to the main control module; the switch quantity acquisition module is used to obtain the switch quantity of the temperature control system and transmit it to the main control module; the switch quantity output module is used to adjust the switch quantity of the temperature control system according to the instructions of the main control module.

6. The control board for the temperature control system according to claim 5, characterized in that: The switch quantity acquisition module includes a resistor voltage divider circuit and an optocoupler isolation chip connected in parallel, wherein the resistor voltage divider circuit is used to divide the collected switch quantity to the optocoupler isolation chip, and the optocoupler isolation chip is used to output the divided switch quantity to the main control module; The switch quantity output module includes a large current switch quantity output circuit and a small current switch quantity output circuit; the large current switch quantity output circuit includes a triode switch, an optocoupler isolation chip, an NMOS tube and a freewheeling diode, the triode switch is connected to the main control module and is connected in series with the input stage of the optocoupler isolation chip, the output stage of the optocoupler isolation chip is connected in parallel with the NMOS tube, and the freewheeling diode is connected in reverse parallel to the D pole of the NMOS tube; the small current switch quantity output circuit includes a Darlington pair integrated chip, and the Darlington pair integrated chip is connected to the main control module.

7. The control board for the temperature control system according to claim 5, characterized in that: It also includes a power supply module, which is used to supply power to the analog quantity acquisition module, the communication module, the main control module, the valve drive module, the switch quantity acquisition module and the switch quantity output module.

8. The control board for the temperature control system according to claim 7, characterized in that: The power module adopts a four-level circuit conversion architecture, including a 24V power input protection circuit, a 24V to 12V DCDC circuit, a 12V to 5V DCDC circuit and a 5V to 3.3V LDO circuit; the 24V power input protection circuit is used to provide a 24V working power supply for the switch quantity acquisition module and the switch quantity output module, the 24V to 12V DCDC circuit is used to provide a 12V working power supply for the valve drive module, the 12V to 5V DCDC circuit is used to provide a 5V working power supply for the analog quantity acquisition module and the communication module, and the 5V to 3.3V LDO circuit is used to provide a 3.3V working power supply for the main control module.

9. The control board for a temperature control system according to claim 8, characterized in that: The power module supplies power to the communication module via an RS485 isolated power circuit, wherein the RS485 isolated power circuit comprises an isolated power chip and a capacitor connected in parallel with the isolated power chip.

10. A compressor cycle refrigeration system, characterized in that: The temperature control is performed by using a control board for a temperature control system as described in any one of claims 1 to 9.

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