Controller capable of expanding six-way electronic expansion valve

Abstract

The utility model relates to a controller, in particular to a controller capable of expanding six electronic expansion valves, which comprises an MCU (microprogrammed control unit) main circuit, a power circuit, an NTC (negative temperature coefficient) input circuit, a voltage type pressure sensor input circuit, an electronic expansion valve driving circuit, an RS485 bus circuit, a CAN (controller area network) bus circuit, a state indicating circuit, a DTU (data transfer unit) onboard interface circuit, a reset circuit and an external storage circuit. The power supply circuit, the NTC input circuit, the voltage type pressure sensor input circuit, the electronic expansion valve output circuit, the RS485 bus circuit, the CAN bus circuit, the state indication circuit, the DTU onboard interface circuit, the reset circuit and the external storage circuit are all connected with the MCU main circuit; and six electronic expansion valves can be expanded.

Description

Technical Field

[0001] The utility model relates to a controller, more specifically a controller capable of expanding 6-way electronic expansion valves. Background Art

[0002] The controller of the expansion valve is usually an electronic device used to monitor and adjust the opening and flow of the expansion valve. The controller can adjust the working state of the expansion valve according to the needs of the system to ensure the stable operation of the system; in the past, when a large number of expansion valves were required for air-conditioning units, a dedicated electronic expansion valve driver could be added. The popular design schemes on the market now have many disadvantages; in the past, each electronic expansion valve required a dedicated electronic expansion valve driver. The popular electronic expansion valve drivers on the market are brands such as Carle, Siemens, or Danfoss, each with a price ranging from several hundred to thousands of yuan, and the cost of the electronic expansion valve itself is also in the thousands of yuan. The current situation is that the cost is high. For each additional electronic expansion valve control, a dedicated electronic expansion valve driver needs to be added, which is costly; when multiple electronic expansion valves are required, multiple 0-10 / 4-20MA control circuits are required, and more controller points are required; when multiple electronic expansion valves are required, multiple dedicated electronic expansion valve drivers are required, and the electronic expansion valve drivers need to be assembled on them, which takes up a large installation space. Therefore, a controller that can expand and control 6 electronic expansion valves is needed. Utility Model Content

[0003] The utility model aims to provide a controller capable of expanding 6-way electronic expansion valves, which can meet the needs of expanding 6-way electronic expansion valves.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] A controller capable of expanding 6-way electronic expansion valves, comprising an MCU main circuit, a power supply circuit, an NTC input circuit, a voltage-type pressure sensor input circuit, an electronic expansion valve drive circuit, an RS485 bus circuit, a CAN bus circuit, a status indication circuit, a DTU onboard interface circuit, a reset circuit and an external storage circuit, wherein the power supply circuit, the NTC input circuit, the voltage-type pressure sensor input circuit, the electronic expansion valve output circuit, the RS485 bus circuit, the CAN bus circuit, the status indication circuit, the DTU onboard interface circuit, the reset circuit and the external storage circuit are all connected to the MCU main circuit;

[0006] The MCU main circuit is a 32-bit MCU STM32F103VET6 chip;

[0007] The power supply circuit provides 3 DC power supplies;

[0008] The NTC input circuit has a total of 14 channels for temperature acquisition;

[0009] The voltage-type pressure sensor input circuit has 6 channels in total, using a resistor voltage divider circuit, and then the MCU chip reads its voltage value through the channel;

[0010] The electronic expansion valve drive circuit has a total of 6 five-wire electronic expansion valve drive circuits, and each electronic expansion valve drive circuit drives the MCU chip through ULN2803 to improve the load capacity;

[0011] The RS485 bus circuit has 2 485 bus communications;

[0012] The CAN bus circuit has a total of 1 CAN bus communication, and uses the CAN chip TJA1050 to realize the transmission and reception of the CAN bus;

[0013] The status indication circuit has a total of 3 LED light emitting diode displays;

[0014] The DTU onboard interface circuit is equipped with a 2G or 4G DTU onboard;

[0015] Reset circuit: There is 1 reset circuit in total;

[0016] The external storage circuit is an external storage chip.

[0017] The beneficial effects of the utility model are:

[0018] The whole integrates 6-channel 5-wire electronic expansion valve drive circuits, 7-channel NTC input circuits, 6-channel (voltage type pressure sensor) analog input circuits, 3-channel RS485 communication, 1-channel CAN communication, 1-channel DTU, 1-channel JLINK circuit, 1-channel serial port debugging port, storage circuit, etc.; it can meet the expansion of 6-channel electronic expansion valves; due to the integrated design, the reliability is greatly improved, and the risk of serious damage to the unit due to communication failure is eliminated; it adopts STMicroelectronics' 32-bit MCU STM32F103VET6 chip and is written in standard C language. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The utility model is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0020] Figure 1 This is a principle block diagram of the controller of the expandable 6-way electronic expansion valve of the utility model;

[0021] Figure 2 It is a schematic diagram of the structure of a controller module of an expandable 6-way electronic expansion valve of the utility model. DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0023] like Figure 1 to Figure 2 As shown, in order to achieve the technical effect of "being able to expand 6-way electronic expansion valves", the structure and function of a controller capable of expanding 6-way electronic expansion valves are described in detail below;

[0024] A controller capable of expanding 6-way electronic expansion valves, comprising an MCU main circuit, a power supply circuit, an NTC input circuit, a voltage-type pressure sensor input circuit, an electronic expansion valve drive circuit, an RS485 bus circuit, a CAN bus circuit, a status indication circuit, a DTU onboard interface circuit, a reset circuit and an external storage circuit, wherein the power supply circuit, the NTC input circuit, the voltage-type pressure sensor input circuit, the electronic expansion valve output circuit, the RS485 bus circuit, the CAN bus circuit, the status indication circuit, the DTU onboard interface circuit, the reset circuit and the external storage circuit are all connected to the MCU main circuit;

[0025] The MCU main circuit is a 32-bit MCU STM32F103VET6 chip; this chip is LQPF-100 package, a 32-bit processor, 512K FLASH memory and 64K RAM space, 72MHz CPU speed, with multiple ADCs and rich resources such as CAN and USART. It is a cost-effective chip suitable for the indoor unit controller of the variable frequency direct expansion machine; the chip can be upgraded through interfaces such as JLINK, CAN or DTU to complete the online upgrade function;

[0026] The power supply circuit provides 3 DC power supplies; 12V, 5V, and 3.3V DC power supplies are provided to provide the power required by the controller; the 13.5VAC power supply, after bridge rectification and filtering, is provided by the LM2596-12 switching power supply with a maximum of 3A 12V DC power supply, and then the MC33269T-5.0G switching power supply provides 5V DC power supply; the 3.3V power supply is provided by the LM1117S-3.3V switching power supply to provide 3.3V DC power supply for the MCU main circuit;

[0027] The NTC input circuit has 14 channels for temperature acquisition; each channel uses an NTC type temperature sensor, which forms a resistance network with a fixed resistor, and then the MCU chip reads its temperature value through the channel; the NTC temperature sensor is a temperature sensing device that changes its resistance value as the temperature changes. Take TH1 as an example: when TH1 is inserted into the module, R24 (10K ohms) is connected in series with the developer TH1, and then coupled to the MCU's PIN15 pin PA5 through R25. Through AD conversion, the chip reads its AD value, and then calculates the voltage across TH1 according to the AD value, and then calculates the resistance value of TH1 at a certain temperature value according to Ohm's law. Then find out the corresponding temperature value according to the RT table;

[0028] The voltage-type pressure sensor input circuit has 6 channels in total, using a resistor voltage divider circuit, and then the MCU chip reads its voltage value through the channel; take PS1 as an example. When the pressure sensor PS1 is inserted, it will generate a voltage value at a certain pressure value, and then it will be divided by R35 and R4. In order not to exceed the 3.3V voltage limit, it will then be coupled to the MCU's PIN30 pin PA5 through R3. Through AD conversion, the chip reads its AD value, and then calculates its actual voltage value according to the AD value. Finally, the actual pressure value is deduced based on the corresponding diagram of the pressure and voltage values ​​of the pressure sensor;

[0029] The electronic expansion valve drive circuit has a total of 6 five-wire electronic expansion valve drive circuits, and each electronic expansion valve drive circuit drives the MCU chip through ULN2803 to improve the load capacity; take EXV1 as an example. When the DPF-TS / S series electronic expansion valve of the Sanhua brand is inserted, the PC15, PC14, PC3, and PE6 ports of the MCU respectively drive the I1, I2, I3, and I4 pins of the U7 (ULU03) chip to perform 4-phase 8-beat excitation to drive the electronic expansion valve, achieving precise step control;

[0030] The RS485 bus circuit has two 485 bus communications. The receiving and sending state of the MAX485 chip is controlled through an I / O port of the chip. When receiving, the MAX48 chip transmits the received data to the receiving pin of the USART of the MCU chip through the A and B bus data of the 6th and 7th pins through the 1st pin. When sending, the sending pin of the USART of the MCU chip transmits the data to the 4th pin of the MAX48, and then transmits the data through the A and B buses of the 6th and 7th pins. Each circuit adopts optical coupling isolation to isolate it from the main circuit.

[0031] The CAN bus circuit has a total of 1 CAN bus communication, and uses the CAN chip TJA1050 to realize the transmission and reception of the CAN bus;

[0032] The state indication circuit has 3 LED light-emitting diodes for display; when the chip pin outputs a low level, the LED lights up; conversely, when the chip pin outputs a high level, the LED goes out;

[0033] The DTU onboard interface circuit is equipped with a 2G or 4G DTU onboard;

[0034] The main chip implements DTU onboard through corresponding pins such as GPRS_txd / rxd / reset, and can realize functions such as remote monitoring and program upgrade for this module;

[0035] Reset circuit There is a total of 1 reset circuit; it uses a mature RC circuit and can be reset externally by pressing a button. Before power-on or when the reset switch is pressed, C45 is at a low level, and then C45 is charged through the resistor R76 (10K ohms) to reset the MCU;

[0036] The external storage circuit is an external storage chip. The W25Q28 (128MB) chip is used to realize the external storage function. The data is stored through the MCU's PB12 (CS), PB13 (SCK), PB14 (MISO), and PB15 (MOSI) SPI bus.

[0037] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A controller capable of expanding 6-way electronic expansion valves, comprising an MCU main circuit, a power supply circuit, an NTC input circuit, a voltage-type pressure sensor input circuit, an electronic expansion valve drive circuit, an RS485 bus circuit, a CAN bus circuit, a status indication circuit, a DTU onboard interface circuit, a reset circuit and an external storage circuit, characterized in that: The power supply circuit, NTC input circuit, voltage-type pressure sensor input circuit, electronic expansion valve output circuit, RS485 bus circuit, CAN bus circuit, status indication circuit, DTU onboard interface circuit, reset circuit and external storage circuit are all connected to the MCU main circuit.

2. A controller capable of expanding 6-way electronic expansion valves according to claim 1, characterized in that: The MCU main circuit is a 32-bit MCU chip.

3. The controller of the expandable 6-way electronic expansion valve according to claim 1, characterized in that: The power supply circuit provides three direct current power supplies.

4. The controller of the expandable 6-way electronic expansion valve according to claim 1, characterized in that: The NTC input circuit has 14 channels for temperature acquisition.

5. The controller of the expandable 6-way electronic expansion valve according to claim 2, characterized in that: The voltage-type pressure sensor input circuit has 6 channels in total, using a resistor voltage divider circuit, and then the MCU chip reads its voltage value through the channel.

6. The controller of the expandable 6-way electronic expansion valve according to claim 2, characterized in that: The electronic expansion valve drive circuit has a total of 6 five-wire electronic expansion valve drive circuits, and each electronic expansion valve drive circuit drives the MCU chip through ULN2803 to improve the load capacity.

7. The controller of the expandable 6-way electronic expansion valve according to claim 1, characterized in that: The RS485 bus circuit has 2 485 bus communications.

8. The controller of the expandable 6-way electronic expansion valve according to claim 1, characterized in that: The CAN bus circuit has a total of 1 CAN bus communication, and uses the CAN chip TJA1050 to realize the transmission and reception of the CAN bus.

9. The controller of the expandable 6-way electronic expansion valve according to claim 1, characterized in that: The state indication circuit has a total of 3 LED light emitting diode displays.

10. The controller of the expandable 6-way electronic expansion valve according to claim 1, characterized in that: The DTU onboard interface circuit has a 2G or 4G DTU onboard, a reset circuit has a total of 1 reset circuit, and the external storage circuit is an external storage chip.

Images