Dual-system electronic expansion valve controller applied to railway vehicle air conditioner

Abstract

The utility model provides a dual-system electronic expansion valve controller applied to a railway vehicle air conditioner. Comprising an MCU control module, a communication module, a first system input module, a second system input module, a first system driving module and a second system driving module, wherein the first system input module and the second system input module are used for collecting railway vehicle system information; the first system driving module is connected with a first electronic expansion valve of a railway vehicle air conditioner; the communication module is connected with the MCU control module; each of the first system input module and the second system input module comprises a thermistor type analog input acquisition circuit, a voltage type analog input acquisition circuit and a current type analog input acquisition circuit. The data information of the two systems can be collected at the same time to correspondingly control the electronic expansion valves of the two systems, and the working efficiency of workers is effectively improved; and corresponding analog quantity output acquisition circuits are adopted for acquisition for different signal types, so that the acquisition precision of the signals can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of rail vehicle air conditioning, and in particular to a dual-system electronic expansion valve controller applied to rail vehicle air conditioning. Background Art

[0002] With the development of technology, traditional control valves used in rail vehicle air conditioning systems, such as thermal expansion valves, cannot respond in real time according to the temperature or pressure of the system in the refrigeration system. The thermal expansion valve has a long delay in responding to superheat, especially the volume delay, which will cause oscillation and instability in the rail vehicle air conditioning system, affecting the economy and safety of the rail vehicle air conditioning system. Therefore, electronic expansion valves are gradually being used to replace thermal expansion valves, and the real-time adjustment of the opening of the electronic expansion valve requires a controller that can accurately control the electronic expansion valve.

[0003] At present, the existing electronic expansion valve controller has the defects of being unable to simultaneously control electronic expansion valves of two systems or more, having few data acquisition channels for the system, and the signal acquisition accuracy cannot meet the actual application requirements. Summary of the invention

[0004] The purpose of the present application is to provide a dual-system electronic expansion valve controller adapted to rail vehicle air conditioning and having multiple data analog quantity acquisition circuits.

[0005] A dual-system electronic expansion valve controller for rail vehicle air conditioning comprises: an MCU control module, a communication module, a first system input module and a second system input module for collecting rail vehicle system information, a first system drive module connected to a first electronic expansion valve of the rail vehicle air conditioning, and a second system drive module connected to a second electronic expansion valve of the rail vehicle air conditioning, wherein the communication module is connected to the MCU control module; the first system input module and the second system input module both comprise a thermistor type analog quantity input acquisition circuit, a voltage type analog quantity input acquisition circuit, and a current type analog quantity input acquisition circuit; the MCU control module comprises a first system data input terminal, a second system data input terminal, a first control signal output terminal, and a second control signal output terminal, wherein the module output terminals of the first system input module and the second system input module are respectively connected to the first system data input terminal and the second system data input terminal; the first control signal output terminal and the second control signal output terminal are respectively connected to the first system drive module and the second system drive module.

[0006] Compared with the prior art, the dual-system electronic expansion valve controller for rail vehicle air conditioning provided by the present application simultaneously collects data information of two rail vehicle systems to correspondingly control the electronic expansion valves of the two rail vehicle systems, effectively improving the work efficiency of the staff in the rail vehicle field and reducing their workload. In addition, the system input module of the dual-system electronic expansion valve controller for rail vehicle air conditioning of the present application includes a variety of data analog quantity acquisition circuits such as thermistor type analog quantity input acquisition circuit, voltage type analog quantity input acquisition circuit and current type analog quantity input acquisition circuit, and adopts corresponding analog quantity output acquisition circuits for acquisition of different signal types, which can effectively improve the signal acquisition accuracy.

[0007] Furthermore, the first system input module and the second system input module both include a first resistor, a second resistor and a first operational amplifier, the positive input terminal of the first operational amplifier is connected to one end of the first resistor and the second resistor respectively; the other end of the first resistor is the module input terminal, and the other end of the second resistor is grounded; the negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the output terminal of the first operational amplifier serves as the module output terminal.

[0008] Furthermore, the first system input module and the second system input module both include a first overvoltage protection tube, a first capacitor, a second capacitor, a first voltage regulator tube and a third resistor. The module input end is grounded through the first overvoltage protection tube; the first capacitor is connected in parallel with the second resistor; the output end of the first operational amplifier serves as the module output end after passing through the third resistor and is grounded through the first voltage regulator tube, and the module output end is also grounded through the second capacitor.

[0009] Furthermore, the first system input module and the second system input module both include a seventh resistor, an eighth resistor, a ninth resistor and a third operational amplifier that can receive external resistance signals to adjust resistance values, the positive input terminal of the third operational amplifier is respectively connected to one end of the seventh resistor, the eighth resistor and the ninth resistor, the other end of the seventh resistor serves as the module input terminal, the other end of the eighth resistor is connected to a preset external power supply, and the other end of the ninth resistor is grounded; the negative input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier, and the output terminal of the third operational amplifier serves as the module output terminal.

[0010] Furthermore, the first system input module and the second system input module also include a third overvoltage protection tube, a fifth capacitor, a sixth capacitor, a tenth resistor and a third voltage regulator tube. The seventh resistor is grounded through the third overvoltage protection tube, and the fifth capacitor is connected in parallel with the ninth resistor. The output end of the third operational amplifier serves as the module output end after passing through the tenth resistor and is grounded through the third voltage regulator tube. The module output end is also grounded through the sixth capacitor.

[0011] In order to provide a clearer understanding of the present application, the specific implementation of the present application will be described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a dual-system electronic expansion valve controller for rail vehicle air conditioning in this application;

[0013] Figure 2 This is a circuit diagram of a voltage-type analog quantity input acquisition circuit of a first system input acquisition and a second system input module of a dual-system electronic expansion valve controller for rail vehicle air conditioning applied to the present application;

[0014] Figure 3 This is a thermistor type analog quantity input acquisition circuit diagram of a first system input acquisition and a second system input module of a dual system electronic expansion valve controller for rail vehicle air conditioning in the present application;

[0015] Figure 4 A control circuit diagram of an MCU control module of a dual-system electronic expansion valve controller for rail vehicle air conditioning according to the present application;

[0016] Figure 5 Another control circuit diagram of an MCU control module of a dual-system electronic expansion valve controller for rail vehicle air conditioning according to the present application;

[0017] Figure 6 A communication circuit diagram of a communication module of a dual-system electronic expansion valve controller for rail vehicle air conditioning according to the present application;

[0018] Figure 7 This is a driving circuit diagram of a first system driving module of a dual-system electronic expansion valve controller applied to a rail vehicle air conditioner in the present application. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present application. It is understood that the drawings are only provided for reference and illustration, and are not used to limit the present application. The connection relationship shown in the drawings is only for the convenience of clear description and does not limit the connection method.

[0021] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component, or there may be an intermediate component at the same time. Unless otherwise defined, all technical and scientific terms used in this document have the same meaning as those generally understood by technicians in the technical field to which this application belongs. It should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or the internal connection of two components. For ordinary technicians in this field, the above terms can be understood in specific circumstances in this utility model.

[0022] The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0023] It should also be noted that in the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0024] See also Figure 1 , Figure 1This is a schematic diagram of a dual-system electronic expansion valve controller for rail vehicle air conditioning in the present application. The present application provides a dual-system electronic expansion valve controller for rail vehicle air conditioning, including: an MCU control module, a communication module, a first system input module and a second system input module for collecting rail vehicle system information, a first system drive module connected to the first electronic expansion valve of the rail vehicle air conditioning, and a second system drive module connected to the second electronic expansion valve of the rail vehicle air conditioning, the communication module is connected to the MCU control module; the first system input module and the second system input module both include a thermistor type analog input acquisition circuit, a voltage type analog input acquisition circuit, and a current type analog input acquisition circuit; the MCU control module includes a first system data input terminal, a second system data input terminal, a first control signal output terminal and a second control signal output terminal, the module output terminals of the first system input module and the second system input are respectively connected to the first system data input terminal and the second system data input terminal; the first control signal output terminal and the second control signal output terminal are respectively connected to the first system drive module and the second system drive module.

[0025] The dual-system electronic expansion valve controller for rail vehicle air conditioning provided in the present application is provided with two system input modules and two system drive modules, the two system input modules can simultaneously receive the temperature signals of the temperature sensors or the pressure signals of the pressure sensors in the two rail vehicle systems to collect analog input, the MCU control module calculates the difference between the superheat and the target superheat according to the analog input, and sends a drive signal to the first system drive module and the second system drive module, the first system drive module and the second system drive module respectively adjust the opening of the electronic expansion valves of the two systems in real time according to the drive signal, thereby adjusting the refrigerant flow entering the evaporator in the air conditioning system, controlling the target superheat, and ensuring the stable operation of the air conditioning system. By controlling two electronic expansion valves simultaneously through a dual-system electronic expansion valve controller for rail vehicle air conditioning, the work efficiency of the staff in the rail vehicle field is effectively improved and their workload is reduced.

[0026] Furthermore, the system input module of the dual-system electronic expansion valve controller applied to rail vehicle air conditioning of the present application includes a variety of data analog quantity acquisition circuits such as thermistor type analog quantity input acquisition circuit, voltage type analog quantity input acquisition circuit and current type analog quantity input acquisition circuit. Corresponding analog quantity output acquisition circuits are used to collect different signal types. For example, the thermistor type analog quantity input acquisition circuit is used to collect the resistance signal converted by the temperature sensor, the voltage type analog quantity input acquisition circuit is used to collect the voltage signal converted by the pressure sensor, and the current type analog quantity input acquisition circuit is used to collect the current signal converted by the pressure sensor, which can effectively improve the signal acquisition accuracy.

[0027] See also Figure 2 , Figure 2 This is a voltage-type analog input acquisition circuit diagram of the first system input acquisition and the second system input module of a dual-system electronic expansion valve controller for rail vehicle air conditioning. In this embodiment, the pressure sensor (not marked in the figure) in the rail vehicle system is responsible for detecting the evaporation pressure and converting the evaporation pressure value into a 0-5V voltage signal. At this time, the first system input module and the second system input module are voltage-type analog input acquisition circuits, both of which include a first resistor R1, a second resistor R2, and a first operational amplifier U1. The positive input end of the first operational amplifier U1 is connected to one end of the first resistor R1 and the second resistor R2 respectively; the other end of the first resistor R1 is the module input end, and the other end of the second resistor R2 is grounded; the negative input end of the first operational amplifier U1 is connected to the output end of the first operational amplifier U1, and the output end of the first operational amplifier U1 serves as the module output end.

[0028] Wherein, the first resistor R1 is preferably a precision resistor with a resistance value of 10000 ohms and a resistance accuracy of 0.1%; the second resistor R2 is preferably a precision resistor with a resistance value of 20000 ohms and a resistance accuracy of 0.1%; the first operational amplifier U1 is an LM2902D operational amplifier. Of course, in other embodiments, according to the requirements of the output voltage range of the actual circuit, the resistance values ​​of the first resistor R1 and the second resistor R2 can be adaptively adjusted. According to the actual data acquisition requirements, the first operational amplifier U1 can also adopt other models.

[0029] The voltage signal generated by the pressure sensor enters the voltage type analog input acquisition circuit of the first system input acquisition and the second system input module from the module input end of the first system input module and the second system input module. According to the voltage value of the voltage signal and the resistance values ​​of the first resistor R1 and the second resistor R2, the final output voltage value of the first system input acquisition and the second system input module is obtained, wherein the output voltage value is controlled within the range of 0-3.3V. The data information of the voltage signal is collected by the first operational amplifier U1, and the resistance accuracy of the first resistor R1 and the second resistor R2 is 0.1%, which effectively improves the collection accuracy of the pressure signal of the rail vehicle system.

[0030] In one embodiment, the first system input module and the second system input module further include a first overvoltage protection tube TVS1, a first capacitor C1, a second capacitor C2, a third resistor R3 and a first voltage regulator tube D1. The module input end is grounded through the first overvoltage protection tube TVS1; the first capacitor C1 is connected in parallel with the second resistor R2; the output end of the first operational amplifier U1 serves as the module output end after passing through the third resistor R3, and is grounded through the first voltage regulator tube D1, and the module output end is also grounded through the second capacitor C2.

[0031] Among them, the first overvoltage protection tube TVS1 is a SMBJ6.5CA transient voltage suppression diode; the capacitance of the first capacitor C1 is 0.47 microfarads, and the capacitance of the second capacitor C2 is 0.1 microfarads; the first voltage regulator D1 is a ZMM3V6 voltage regulator diode; the third resistor R3 is preferably a resistor with a resistance value of 1000 ohms. Of course, in other embodiments, according to the actual voltage conditions in the circuit, the capacitance of the first capacitor C1, the second capacitor C2 and the resistance value of the third resistor R3 can be adaptively adjusted, and the first voltage regulator TVS1 uses other models such as SMCJ transient voltage suppression diodes, and the first voltage regulator D1 uses other models such as LM317 voltage regulator diodes.

[0032] By setting the first capacitor C1, the third resistor R3 and the second capacitor C2, before the voltage signal enters the first operational amplifier U1, the first capacitor C1 filters the voltage signal; and before the output ends of the first system input module and the second system input module output the voltage signal, the second capacitor C2 filters the voltage signal, thereby improving the accuracy of the data information of the voltage signal. At the module input ends of the first system input module and the second system input module, the first overvoltage protection tube TVS1 is grounded, which can effectively prevent the overvoltage of the voltage signal from causing damage to the internal circuit. At the module output ends of the first system input module and the second system input module, the first voltage regulator tube D1 is grounded to ensure that the voltage value of the output voltage signal will not be too high and cause damage to the MCU control module.

[0033] In one embodiment, the pressure sensor can also convert the evaporation pressure value into a 4-20mA current signal. At this time, the first system input module and the second system input module are current type analog input acquisition circuits; the first resistor R1 is preferably a resistor with a resistance value of 0 ohm; the second resistor R2 is preferably a precision resistor with a resistance value of 150 ohm and a resistance accuracy of 0.1%. Of course, in other embodiments, the resistance value of the second resistor R2 can be adaptively adjusted according to the requirements of the actual circuit output voltage range.

[0034] The current signal generated by the pressure sensor enters the current-type analog input acquisition circuit of the first system input acquisition and the second system input module from the module input end of the first system input module and the second system input module. By setting the first resistor R1 with a resistance value of 0, overcurrent protection can be provided to the current-type analog input acquisition circuit. The final output voltage value of the first system input acquisition and the second system input module is determined according to the resistance value of the second resistor R2 and the current intensity of the current signal, wherein the output voltage value is controlled within the range of 0-3.3V. The data information of the current signal is collected by the second operational amplifier U2, and the resistance accuracy of the fifth resistor R5 and the sixth resistor R6 is 0.1%, which effectively improves the collection accuracy of the pressure signal of the rail vehicle system.

[0035] See also Figure 3 , Figure 3 This is a thermistor type analog input acquisition circuit diagram of the first system input acquisition and the second system input module of a dual system electronic expansion valve controller for rail vehicle air conditioning. In one embodiment, a temperature sensor (not shown in the figure) is also provided in the rail vehicle system, and the temperature sensor can be converted into a resistance value signal according to the temperature change value, wherein the temperature of the rail vehicle system is in the range of -40℃-105℃. At this time, the first system input module and the second system input module are thermistor type analog input acquisition circuits, both of which include a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a third operational amplifier U3 that can receive an external resistance signal and adjust the resistance value, the positive input end of the third operational amplifier U3 is respectively connected to one end of the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9, the other end of the seventh resistor R7 is used as the module input end, the other end of the eighth resistor R8 is connected to a preset external power supply, and the other end of the ninth resistor R9 is grounded; the negative input end of the third operational amplifier U3 is connected to the output end of the third operational amplifier U3, and the output end of the third operational amplifier U3 is used as the module output end.

[0036] Among them, the variable range of the resistance value of the seventh resistor R7 is 0.832 ohms-200K ohms, the eighth resistor R8 is preferably a precision resistor with a resistance value of 20K ohms and a resistance accuracy of 0.1%; the ninth resistor R9 is preferably a precision resistor with a resistance value of 10K ohms and a resistance accuracy of 0.1%; the third operational amplifier U3 is an LM2902D operational amplifier. Of course, in other embodiments, according to the requirements of the actual circuit output voltage range, the resistance values ​​of the eighth resistor R8 and the ninth resistor R9 can be adaptively adjusted. According to the actual data acquisition requirements, the third operational amplifier U3 can also use other models; according to the temperature range in the system, the variable range of the resistance value of the seventh resistor R7 is adaptively modified.

[0037] The resistance value signal generated by the temperature sensor can change the resistance value of the seventh resistor R7 accordingly, and determine the final output voltage value of the current type analog input acquisition circuit of the first system input acquisition and the second system input module according to the resistance values ​​of the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9, wherein the output voltage value is controlled within the range of 0-3.3 V. The data information of the current signal is collected by the third operational amplifier U3, and the resistance accuracy of the eighth resistor R8 and the ninth resistor R9 is 0.1%, which effectively improves the collection accuracy of the pressure signal of the rail vehicle system.

[0038] In another embodiment, the first system input module and the second system input module further include a third overvoltage protection tube TVS3, a fifth capacitor C5, a sixth capacitor C6, a tenth resistor R10 and a third voltage regulator tube D3, the seventh resistor R7 is grounded through the third overvoltage protection tube TVS3, the fifth capacitor C5 is connected in parallel with the ninth resistor R9; the output end of the third operational amplifier U3 passes through the tenth resistor R10 as the module output end, and is grounded through the third voltage regulator tube D3, and the module output end is also grounded through the sixth capacitor C6.

[0039] Among them, the third overvoltage protection tube TVS3 is a SMBJ6.5CA transient voltage suppression diode; the capacitance of the fifth capacitor C5 is 0.47 microfarads, and the capacitance of the sixth capacitor C6 is 0.1 microfarads; the third voltage regulator D3 is a ZMM3V6 voltage regulator diode; the sixth resistor R10 is preferably a resistor with a resistance value of 1000 ohms. Of course, in other embodiments, according to the actual voltage conditions in the circuit, the capacitance of the fifth capacitor C5, the sixth capacitor C6 and the resistance value of the sixth resistor R10 can be adaptively adjusted, and the second voltage regulator TVS2 uses other types such as SMCJ transient voltage suppression diodes, and the second voltage regulator D2 uses other types such as LM317 voltage regulator diodes.

[0040] By setting the fifth capacitor C5, the tenth resistor R10 and the sixth capacitor C6, before the voltage signal provided by the external power supply enters the third operational amplifier U3, the fifth capacitor C5 filters the current signal; and before the module output ends of the first system input module and the second system input module output the voltage signal, the sixth capacitor C6 filters the voltage signal to improve the accuracy of the data information of the voltage signal. At the module input ends of the first system input module and the second system input module, the second overvoltage protection tube TVS2 is grounded, which can effectively prevent the overcurrent of the current in the circuit or the overvoltage of the voltage from causing damage to the internal circuit. At the module output ends of the first system input module and the second system input module, the second voltage regulator tube D2 is grounded to ensure that the voltage value of the output voltage signal will not be too high, thereby causing damage to the MCU control module.

[0041] See also Figure 4 , Figure 4 This is a control circuit diagram of an MCU control module of a dual-system electronic expansion valve controller for rail vehicle air conditioning in this application. The MCU control module includes an MCU control chip MCU1, and the MCU control chip is embedded with a Flash memory, an SRAM memory, a 3-way SPI module and a JTAG debugging interface. In this embodiment, the MCU control chip MCU1 is a GD32F303CET6 chip, the 16th pin of the MCU control chip MCU1 is a first system temperature analog input pin 16, the 18th pin of the MCU control chip MCU1 is a first system pressure analog input pin 18, the first system temperature analog input pin 16 and the first system pressure analog input pin 18 serve as the first system data input terminal, the 17th pin of the MCU control chip MCU1 is a second system temperature analog input pin 17, the 19th pin of the MCU control chip MCU1 is a second system pressure analog input pin 19, the second system temperature analog input pin 17 and the second system pressure analog input pin 19 serve as the second system data input terminal.

[0042] The first system temperature analog input pin 16 and the second system temperature analog input pin 17 are electrically connected to the module output end of the thermistor type analog input acquisition circuit of the first system input module and the second system input module respectively; the first system pressure analog input pin 18 and the second system pressure analog input pin 19 are electrically connected to the module output end of the voltage type analog input acquisition circuit or the current type analog input acquisition circuit of the first system input module and the second system input module respectively. The 26th to 29th pins of the MCU control chip are all the first system control signal output pins, and as the first control signal output end, they are used to be electrically connected to the first system drive module; the 30th to 33rd pins of the MCU control chip MCU1 are all the second system control signal output pins, and as the second control signal output end, they are used to be electrically connected to the second system drive module; the 12th to 14th pins of the MCU control chip MCU1 are all communication pins, which are used to be electrically connected to the communication module. Of course, according to actual needs, the MCU1 can also use other types of chips.

[0043] The 1st pin, the 9th pin, the 24th pin, the 36th pin and the 48th pin of the MCU control chip MCU1 are all power pins, and are respectively connected to an external power supply of 3.3V, and the 8th pin, the 10th pin, the 20th pin, the 23rd pin, the 35th pin, the 44th pin and the 47th pin are all ground pins, and are grounded. In one embodiment, in order to improve the quality of the input power supply, the power pin 8 and the ground pin 9 of the MCU control chip MCU1 are connected in parallel with the seventh capacitor C7 and the eighth capacitor C8, and the capacitance of the seventh capacitor C7 and the eighth capacitor C8 are both 1 microfarad. To ensure that the MCU1 is in a low-level state in order to ensure that the pin of the fixed function of the communication module is in a low-level state, the 10th pin is grounded through the 11th resistor R11, the 20th pin is grounded through the 15th resistor R15, and the 44th pin is grounded through the 24th resistor R24. Wherein, the resistance values ​​of the 11th resistor R11, the 15th resistor R15 and the 24th resistor R24 ​​are all 10K ohms. Of course, in other embodiments, the capacitance of the seventh capacitor C7 and the eighth capacitor C8, as well as the resistance values ​​of the eleventh resistor R11, the fifteenth resistor R15 and the twenty-fourth resistor R24 ​​can be adaptively adjusted according to actual circuit conditions.

[0044] In one embodiment, in order to ensure that the voltage signal output by the MCU control chip MCU1 does not have an excessively high peak voltage, which would damage the first system drive module and the second system drive module. The first system control signal output pins 26-29 of the MCU control chip MCU1 are respectively connected in series with the twenty-third resistor R23, the twenty-second resistor R22, the twenty-first resistor R21 and the twentieth resistor R20 with a resistance of 22 ohms; the second system control signal output pins 30-33 of the MCU control chip MCU1 are respectively connected in series with the nineteenth resistor R19, the eighteenth resistor R18, the seventeenth resistor R17 and the sixteenth resistor R16 with a resistance of 22 ohms. In order to ensure that the communication module does not generate ringing during the communication process, which would damage the MCU control chip MCU1, the communication pins 12-14 of the MCU control chip MCU1 are respectively connected in series with the eleventh resistor R11, the twelfth resistor R12 and the thirteenth resistor R13 with a resistance of 22 ohms. Of course, in other embodiments, the resistance values ​​of the twenty-third resistor R23, the twenty-second resistor R22, the twenty-first resistor R21, the twentieth resistor R20, the nineteenth resistor R19, the eighteenth resistor R18, the seventeenth resistor R17, the sixteenth resistor R16, the eleventh resistor R11, the twelfth resistor R12 and the thirteenth resistor R1 can be adaptively adjusted according to actual needs.

[0045] The thermistor type analog quantity input acquisition circuit of the first system input module and the thermistor type analog quantity input acquisition circuit of the second system input module respectively acquire the temperature change analog quantity of the first rail vehicle system and the temperature change analog quantity of the second rail vehicle system, and output them to the MCU control chip MCU1; the voltage type analog quantity input acquisition circuit or the current type analog quantity input acquisition circuit of the first system input module and the voltage type analog quantity input acquisition circuit or the current type analog quantity input acquisition circuit of the second system input module respectively acquire the pressure change analog quantity of the evaporator of the first rail vehicle system and the pressure change analog quantity of the evaporator of the second rail vehicle system, and output them to the MCU control chip MCU1. The control chip MCU1 calculates the current actual superheat of the first rail vehicle system according to the temperature change analog quantity and the pressure change analog quantity of the first rail vehicle system; refers to the preset required superheat of the rail vehicle system; and generates a first drive signal for adjusting the opening of the electronic expansion valve of the first rail vehicle system according to the actual superheat and the required superheat of the first rail vehicle system; the control chip MCU1 calculates the current actual superheat of the second rail vehicle system according to the temperature change analog quantity and the pressure change analog quantity of the second rail vehicle system; refers to the preset required superheat of the rail vehicle system; and generates a second drive signal for adjusting the opening of the electronic expansion valve of the second rail vehicle system according to the actual superheat and the required superheat of the second rail vehicle system.

[0046] In one embodiment, the 41st pin and the 42nd pin of the MCU control chip MCU1 are both function selection pins, the function selection pin 41 is electrically connected to one end of the 26th resistor R26, the function selection pin 42 is electrically connected to the 25th resistor R25, and the other end of the 26th resistor R26 is electrically connected to the other end of the 25th resistor R25. A 3.3V external power supply is connected to the connection circuit of the 25th resistor R25 and the 26th resistor R26. At this time, the MCU control chip MCU1 calculates the actual overheating of the first rail vehicle system and the second rail vehicle system according to the temperature signal and pressure signal of the first rail vehicle system, as well as the temperature signal and pressure signal of the second rail vehicle system.

[0047] In another embodiment, see Figure 5 , Figure 5Another control circuit diagram of the MCU control module of the dual-system electronic expansion valve controller for rail vehicle air conditioning is provided in the present application. The function selection pin 41 is electrically connected to one end of the twenty-eighth resistor R28, the function selection pin 42 is electrically connected to the twenty-seventh resistor R27, and the other end of the twenty-eighth resistor R28 is electrically connected to the other end of the twenty-seventh resistor R27. Ground is connected in the connection circuit between the twenty-eighth resistor R28 and the twenty-seventh resistor R27. At this time, the MCU control chip MCU1 only calculates the actual superheat of the first rail vehicle system and the second rail vehicle system based on the pressure signal of the first rail vehicle system and the pressure signal of the second rail vehicle system.

[0048] See also Figure 7 , Figure 7 This is a driving circuit diagram of the first system driving module of a dual-system electronic expansion valve controller for rail vehicle air conditioning in this application. In this embodiment, the driving chips STM of the first system driving module and the second system driving module both use TBD62064APG chips, and the 3rd, 6th, 11th and 14th pins of the driving chip STM are all first system control signal receiving pins, and the first system control signal receiving pins are electrically connected to the first system control signal output pins 26-29 of the MCU control chip MCU1 respectively; the driving chip STM is the first system electronic expansion drive signal output pin through its 2nd, 7th, 9th and 16th pins, and the first system electronic expansion drive signal output pins 2, 7, 9, 16 are connected to the electronic expansion valve of the first rail vehicle system; the 1st and 8th pins of the driving chip STM are both power pins, and are connected to a 12V power supply; the 4th and 5th pins are both ground pins, and the two are grounded after being connected. The 12th and 13th pins are both ground pins, and the two are grounded after being connected. The driving chip STM receives the first driving signal from the MCU control chip MCU1 and gradually adjusts the electronic expansion valve of the first rail vehicle system in real time.

[0049] The circuit structure of the second system driver module is the same as that of the first system driver module, so it is not repeated here. Of course, in other embodiments, according to actual conditions, the driver chips STM of the first system driver module and the second system driver module can also use other types of chips.

[0050] In one embodiment, light emitting diodes are respectively connected in series in the connection circuits between the first system electronic expansion drive signal output pins 2, 7, 9, 16 and the electronic expansion valve of the first rail vehicle system, and the light emitting diodes are also provided in the connection circuits between the second system drive module and the electronic expansion valve of the second rail vehicle system. The brightness of the light emitting diodes facilitates the staff to monitor the working conditions of the first system drive module and the second system drive module.

[0051] See also Figure 6 , Figure 6 This is a communication circuit diagram of a communication module of a dual-system electronic expansion valve controller for rail vehicle air conditioning. In this embodiment, the communication chip IC1 of the communication module adopts the ADM2483 chip. The 3rd, 5th and 6th pins of the communication chip IC1 are all communication data output pins, and the communication data output pins 6, 5, and 3 are electrically connected to the communication pins 12-14 of the MCU control chip MCU1 respectively. The 1st and 16th pins of the communication chip IC1 are both power pins and are connected to the power supply; the 2nd, 8th, 9th and 15th pins of the communication chip IC1 are all ground pins and are grounded; the 12th pin of the communication chip IC1 is the external device access pin 12, and is electrically connected to the external device access terminal 485_A3; the 13th pin of the communication chip IC1 is the external device access pin 13, and is electrically connected to the external device access terminal 485_B3.

[0052] In one embodiment, the 12th pin of the communication chip IC1 is electrically connected to the power pin 16 of the communication chip IC1 through a pull-up resistor R33; the external device access pin 13 of the communication chip IC1 is electrically connected to the ground pin 9 of the communication chip IC1 through a pull-down resistor R32. The resistance value of the pull-up resistor R33 is 680 ohms, and the resistance value of the pull-down resistor R32 is 680 ohms. The external device access pin 12 of the communication chip IC1 is electrically connected to the external device access pin 13 of the communication chip IC1 through a terminal resistor R36, wherein the resistance value of the terminal resistor R33 is 120 ohms. By providing the terminal resistor R36, in long-line signal transmission, signal reflection and echo can be avoided to ensure stable transmission of signal quality. By setting the pull-up resistor R32 and the pull-down resistor R33 with a resistance value of 680 ohms, it is ensured that after the terminal resistor R36 is connected, the absolute value of the voltage between the external device access terminal 485_A3 and the external device access terminal 485_B3 is greater than 200mv. Of course, according to the actual voltage difference range requirement between the external device access terminal 485_A3 and the external device access terminal 485_B3, the resistance values ​​of the pull-up resistor R32 and the pull-down resistor R33 are adaptively adjusted; according to the actual signal reflection and echo conditions, the resistance value of the terminal resistor R36 is adaptively modified.

[0053] In another embodiment, the communication circuit further includes a thirty-fourth resistor R34 and a thirty-fifth resistor R35, and the external device access pin 12 of the communication chip IC1 is electrically connected to the external device access terminal 485_A3 through the thirty-fourth resistor R34; the external device access pin 13 of the communication chip IC1 is electrically connected to the external device access terminal 485_B3 through the thirty-fifth resistor R35. Among them, the resistance value of the thirty-fourth resistor R34 and the thirty-fifth resistor R35 is 5.1Ω, and the thirty-fourth resistor R34 and the thirty-fifth resistor R35 can effectively eliminate the ringing phenomenon caused by signal feedback in the circuit, thereby improving the communication quality between the external device and the MCU control chip MCU1. Of course, according to the actual circuit situation, the resistance value of the thirty-fourth resistor R34 and the thirty-fifth resistor R35 can be adaptively adjusted.

[0054] In one embodiment, the communication circuit further includes a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a twenty-ninth resistor R29, a thirtieth resistor R30, a thirty-first resistor R31, a fourth overvoltage protection tube TVS4, a fifth overvoltage protection tube TVS5, and a sixth overvoltage protection tube TVS6. The power pin 1 and the ground pin 2 of the communication chip IC1 are connected through the ninth capacitor C9, the tenth capacitor C10, and the eleventh capacitor C11, and the ninth capacitor C9, the tenth capacitor C10, and the eleventh capacitor C11 are connected in parallel, wherein the capacitance of the ninth capacitor C9, the tenth capacitor C10, and the eleventh capacitor C11 is 10 microfarads, and the maximum withstand voltage is 16V. The 16th pin of the communication chip IC1 is grounded through the twelfth capacitor C12, and the capacitance of the twelfth capacitor C12 is 0.1 microfarad.

[0055] The communication data output pin 3 of the communication chip IC1 is connected to the external power supply through the thirty-first resistor R31, the communication data output pin 5 of the communication chip IC1 is connected to the external power supply through the thirtieth resistor R30, and the communication data output pin 6 of the communication chip IC1 is connected to the external power supply through the twenty-ninth resistor R29, and the twenty-ninth resistor R29, the thirtieth resistor R30 and the thirty-first resistor R31 are connected in parallel, wherein the resistance value of the twenty-ninth resistor R29, the thirtieth resistor R30 and the thirty-first resistor R31 is 10K ohms.

[0056] The fifth overvoltage protection tube TVS5 is electrically connected in parallel with the thirty-sixth resistor, one end of the fifth overvoltage protection tube TVS5 is grounded through the fourth overvoltage protection tube TVS4, and the other end of the fifth overvoltage protection tube TVS5 is grounded through the sixth overvoltage protection tube TVS6. The fourth overvoltage protection tube TVS4 and the sixth overvoltage protection tube TVS6 are both SMBJ6.5CA transient voltage suppression diodes, and the fifth overvoltage protection tube TVS5 is a SMBJ12CA transient voltage suppression diode.

[0057] When the power consumption of the circuit suddenly increases, by setting the ninth capacitor C9, the tenth capacitor C10, the eleventh capacitor C11 and the twelfth capacitor C12, the stored electric energy can be temporarily released, the power supply voltage can be stabilized, and the stability of the circuit can be protected; and the small-capacity capacitor can block the DC signal through the high-frequency signal, thereby bypassing this noise to the ground, reducing the power supply noise and improving the stability of the circuit. In addition, by setting the fourth overvoltage protection tube TVS4, the fifth overvoltage protection tube TVS5 and the sixth overvoltage protection tube TVS6, the overcurrent of the current in the circuit or the overvoltage of the voltage can be effectively prevented from causing damage to the internal circuit. By setting the twenty-ninth resistor R29, the thirtieth resistor R30 and the thirty-first resistor R31, it can play the role of voltage division or current limiting, and can effectively protect the pins of the communication chip IC1.

[0058] Of course, in other embodiments, according to the actual circuit conditions, the capacitance values ​​of the ninth capacitor C9, the tenth capacitor C10, the eleventh capacitor C11 and the twelfth capacitor C12 can be adaptively adjusted; the resistance values ​​of the twenty-ninth resistor R29, the thirtieth resistor R30 and the thirty-first resistor R31 can be adaptively adjusted; and the fourth overvoltage protection tube TVS4, the fifth overvoltage protection tube TVS5 and the sixth overvoltage protection tube TVS6 can also adopt other types of diodes.

[0059] In this application, the dual-system electronic expansion valve controller applied to rail vehicle air conditioning has two working modes:

[0060] 1. Automatic control working mode, collecting sensor data (such as temperature and pressure, etc.) of the first rail vehicle system and the second rail vehicle system through the first system input module and the second acquisition system input module; when the MCU control module determines that the sensor data is invalid, it outputs a control signal to the first system drive module and the second system drive module, so that the electronic expansion valves of the first rail vehicle system and the second rail vehicle system maintain a default opening state; when the MCU control module determines that the sensor data is valid, the MCU control module calculates the current superheat according to the sensor data; the MCU control module compares the current superheat with the preset target superheat, and outputs a control signal to the first system drive module and the second system drive module, thereby adjusting the opening of the electronic expansion valves of the first rail vehicle system and the second rail vehicle system.

[0061] 2. External control mode: the MCU control module communicates with the external device through the RS485 interface of the communication module to obtain the external device control information in real time; the MCU control module outputs a control signal to the first system drive module and the second system drive module according to the external device control information, thereby adjusting the opening of the electronic expansion valve of the first rail vehicle system and the second rail vehicle system.

[0062] The present application is not limited to the above-mentioned implementation modes. If various changes or modifications to the present application do not depart from the spirit and scope of the present application, and if these changes and modifications fall within the claims of the present application and the scope of equivalent technologies, the present application is also intended to include these changes and modifications.

Claims

1. A dual-system electronic expansion valve controller for rail vehicle air conditioning, characterized in that: include: An MCU control module, a communication module, a first system input module and a second system input module for collecting rail vehicle system information, a first system drive module connected to a first electronic expansion valve of an air conditioner of a rail vehicle, and a second system drive module connected to a second electronic expansion valve of an air conditioner of a rail vehicle, wherein the communication module is connected to the MCU control module; the first system input module and the second system input module both include a thermistor type analog quantity input acquisition circuit, a voltage type analog quantity input acquisition circuit, and a current type analog quantity input acquisition circuit; the MCU control module includes a first system data input terminal, a second system data input terminal, a first control signal output terminal, and a second control signal output terminal, and the module output terminals of the first system input module and the second system input are respectively connected to the first system data input terminal and the second system data input terminal; the first control signal output terminal and the second control signal output terminal are respectively connected to the first system drive module and the second system drive module.

2. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 1, characterized in that: The first system input module and the second system input module both include a first resistor, a second resistor and a first operational amplifier, the positive input terminal of the first operational amplifier is connected to one end of the first resistor and the second resistor respectively; the other end of the first resistor is the module input terminal, and the other end of the second resistor is grounded; the negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the output terminal of the first operational amplifier serves as the module output terminal.

3. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 2, characterized in that: The first system input module and the second system input module both include a first overvoltage protection tube, a first capacitor, a second capacitor, a first voltage regulator tube and a third resistor. The module input end is grounded through the first overvoltage protection tube; the first capacitor is connected in parallel with the second resistor; the output end of the first operational amplifier passes through the third resistor as the module output end and is grounded through the first voltage regulator tube. The module output end is also grounded through the second capacitor.

4. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 1, characterized in that: The first system input module and the second system input module both include a seventh resistor, an eighth resistor, a ninth resistor and a third operational amplifier that can receive external resistance signals to adjust resistance values. The positive input terminal of the third operational amplifier is connected to one end of the seventh resistor, the eighth resistor and the ninth resistor, respectively. The other end of the seventh resistor serves as the module input terminal, the other end of the eighth resistor is connected to a preset external power supply, and the other end of the ninth resistor is grounded; the negative input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier, and the output terminal of the third operational amplifier serves as the module output terminal.

5. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 4, characterized in that: The first system input module and the second system input module both further include a third overvoltage protection tube, a fifth capacitor, a sixth capacitor, a tenth resistor and a third voltage regulator tube, the seventh resistor is grounded through the third overvoltage protection tube, and the fifth capacitor is connected in parallel with the ninth resistor; The output end of the third operational amplifier is used as the module output end after passing through the tenth resistor and is grounded through the third voltage regulator tube. The module output end is also grounded through the sixth capacitor.

6. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 1, characterized in that: The MCU control module includes an MCU control chip, and the MCU control chip is provided with a first system temperature analog input pin, a first system pressure analog input pin, a second system temperature analog input pin, a second system pressure analog input pin, a first system control signal output pin and a second system control signal output pin. The first system temperature analog input pin and the second system temperature analog input pin are electrically connected to the module output ends of the thermistor type analog input acquisition circuit of the first system input module and the second system input module respectively; the first system pressure analog input pin and the second system pressure analog input pin are electrically connected to the module output ends of the voltage type analog input acquisition circuit or the current type analog input acquisition circuit of the first system input module and the second system input module respectively; the first system control signal output pin serves as the first control signal output end; and the second system control signal output pin serves as the second control signal output end.

7. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 6, characterized in that: The first system driving module includes a driving chip, and the driving chip is provided with a first system control signal receiving pin and a first system electronic expansion driving signal output pin, the first system control signal receiving pin is connected to the first system control signal output pin; the first system electronic expansion driving signal output pin is connected to the electronic expansion valve of the first rail vehicle system.

8. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 7, characterized in that: A light emitting diode is connected in a connection circuit between the first system electronic expansion drive signal output pin and the electronic expansion valve of the first rail vehicle system.

9. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 7, characterized in that: The MCU control chip is a GD32F303CET6 chip, and the driver chip is a TBD62064APG chip.

10. A dual-system electronic expansion valve controller for rail vehicle air conditioning according to claim 6, characterized in that: The communication module includes a communication chip, which is provided with a communication data output pin and an external device access pin; the MCU control chip is provided with a communication pin, and the communication data output pin is connected to the communication pin; the external device is connected to the communication chip through the external device access pin.

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