Electronic expansion valve drive and heat pump device

Abstract

This invention discloses an electronic expansion valve driver and a heat pump device. The driver includes a power module, a MODBUS-RTU communication interface, an LCD display, an input unit, an output unit, and a microprocessor. Its core feature is that the driver receives opening commands from a host computer (such as a PLC) via the MODBUS-RTU communication interface. The microprocessor then directly drives the electronic expansion valve to operate, eliminating the need for local sensor signal acquisition and superheat calculation. This solution transfers complex algorithmic computation tasks to the host computer, significantly reducing the local hardware cost and complexity of the driver. This invention also boasts advantages such as strong compatibility (supporting various brands and models of electronic expansion valves), simple wiring, easy installation and maintenance, and support for UPS backup power for power outage protection. It is particularly suitable for heat pump systems requiring low cost, high reliability, and centralized control.

Description

Technical Field

[0001] This utility model relates to the field of heat pump control system technology, specifically to an electronic expansion valve driver for a heat pump device and a heat pump device using the driver. Background Technology

[0002] Existing electronic expansion valve control systems typically collect evaporator temperature and pressure data from sensors, calculate superheat, and then use a PID algorithm to control a stepper motor to drive the valve needle, thereby changing the valve opening and adjusting the refrigerant flow.

[0003] While electronic expansion valves (EEVs) offer advantages such as high control precision and fast response, they also have some drawbacks in practical applications:

[0004] 1. The hardware cost is too high, requiring matching controllers, sensors (temperature / pressure) and drive circuits, which increases the system cost.

[0005] 2. It relies on electronic control and requires the use of PID algorithms or intelligent control strategies. Parameter tuning is complex (such as the tuning of KP, KI, and KD), and it places high demands on the performance of the controller (such as MCU computing power and anti-interference capabilities).

[0006] 3. The system has strict matching requirements and needs to be dynamically matched with components such as compressors, evaporators, and condensers. Otherwise, oscillations (such as large fluctuations in superheat) are likely to occur. In variable frequency systems, the algorithm needs to be adjusted quickly when the load changes drastically.

[0007] Existing electronic expansion valve actuators typically require dedicated controllers and sensors, resulting in poor compatibility, complex installation and wiring, and difficulties in mass production and maintenance.

[0008] Therefore, it is necessary to provide a new technical solution. Utility Model Content

[0009] The purpose of this invention is to provide an electronic expansion valve actuator that is compact, low-cost, highly compatible, and easy to install, so as to solve the above-mentioned problems existing in the prior art.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] On one hand, an electronic expansion valve actuator is provided, characterized in that it comprises:

[0012] The power module provides a 24V DC power supply.

[0013] The MODBUS-RTU communication interface is used for data communication with the host computer.

[0014] An LCD screen is used to display device status and settings.

[0015] The input unit receives an external start signal, triggering the driver to begin operation.

[0016] The output unit is used to output fault signals;

[0017] The microprocessor is connected to the power module, MODBUS-RTU communication interface, LCD display, input unit and output unit respectively, and is used to receive control commands, output fault signals and change the valve opening of the electronic expansion valve according to the received information.

[0018] Furthermore, the MODBUS-RTU communication interface communicates with the PLC or logic controller via the RS485 protocol, receives opening control commands, and uploads equipment status information.

[0019] Furthermore, the input unit receives a low-level active start signal, triggering the microprocessor to enter the working mode.

[0020] Furthermore, the output unit includes normally open relays and normally closed relays for outputting alarm signals.

[0021] Furthermore, the driver also supports an external UPS power supply to maintain the valve opening or close the valve after the main power supply fails.

[0022] Furthermore, the driver supports electronic expansion valves of models DPFO, DPFQ, UKV, SKV, and PKV with a drive current of less than 1.2A.

[0023] On the other hand, a heat pump device is provided, including the aforementioned electronic expansion valve driver.

[0024] This utility model has the following beneficial effects:

[0025] 1. Significantly reduce system costs:

[0026] Save core controller resources: The driver itself is not responsible for complex overheating calculations and PID operations. These computationally demanding tasks are moved to the host computer such as PLC, thereby allowing the use of lower-cost, lower-performance microprocessors (MCUs).

[0027] Reduced reliance on sensors: The driver does not need to be directly connected to temperature and pressure sensors, saving on hardware costs for sensors, related cables, and signal processing circuits.

[0028] Centralized control: One PLC can control multiple such drives through an RS485 bus, realizing distributed control. Compared with the solution of equipping each electronic expansion valve with an independent high-end controller, it greatly saves the overall cost.

[0029] 2. Simplify system structure and wiring:

[0030] "Plug and play" installation: The driver communicates with the host computer through a standard RS485 (Modbus-RTU) interface, and the wiring is simple and standardized, which greatly simplifies the wiring complexity in the electrical control cabinet.

[0031] Compact structure: It integrates drive, communication and human-machine interaction into a compact unit, reducing the number of independent components in the system and saving installation space.

[0032] 3. Improve control response speed and reliability:

[0033] Rapid command execution: The driver is dedicated to driving functions. After receiving the precise opening command from the host computer, it can quickly drive the motor to move, avoiding the delay caused by signal acquisition and calculation in traditional solutions.

[0034] Separation of duties ensures high reliability: Complex algorithms run on the host computer, while the driver focuses on execution, reducing the risk of the entire system's computing function being paralyzed due to the failure of a single controller. Furthermore, the simplified driver structure reduces potential points of failure.

[0035] 4. Enhanced compatibility and versatility:

[0036] The valve body has strong compatibility: it clearly supports electronic expansion valves from various brands (such as DPFO, DPFQ, UKV, etc.) and various working modes (4-phase 4-step / 8-step) with a drive current of less than 1.2A, making it applicable to a very wide range of applications.

[0037] The system is highly adaptable: the standard Modbus communication protocol allows it to be easily integrated into existing PLCs, DCSs or building automation systems without the need for customized complex communication interfaces.

[0038] 5. Improve installation and maintenance convenience:

[0039] Easy to install: The wiring method is simple and clear. Ordinary technicians can complete the installation and wiring after a short training, reducing the reliance on professional electrician skills.

[0040] Easy maintenance and monitoring: Equipped with a local LCD screen, it can display the working status and parameters in real time, facilitating on-site debugging and fault diagnosis. A dedicated alarm output terminal can promptly report faults, enabling rapid response and handling.

[0041] 6. Improve system security and reliability:

[0042] Power failure protection mechanism: The unique dual power interface design supports external UPS backup power. In the event of a main power failure, it can maintain the valve position or close the valve according to a preset safety strategy, effectively preventing damage to the heat pump system due to sudden valve position changes and protecting core equipment.

[0043] 7. Facilitates mass production and quality control:

[0044] As a standardized and modular functional unit, the driver has a unified structure and relatively fixed software functions, which is very conducive to large-scale and standardized production, thereby ensuring stable product quality and further reducing costs.

[0045] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a system structure diagram provided in an embodiment of the present utility model.

[0048] Figure 2 This is a schematic diagram of the terminal structure provided in an embodiment of the present utility model. Detailed Implementation

[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0050] This utility model discloses an electronic expansion valve actuator, reference... Figure 1 The driver includes a power module 1, a MODBUS-RTU communication interface 2, an LCD display 3, an input unit 4, an output unit 5, and a microprocessor 6.

[0051] The system includes a power module 1 providing 24V DC power, a MODBUS-RTU communication interface 2 for data communication with a host computer to remotely control the opening of the electronic expansion valve and upload equipment status information, an LCD screen 3 to display equipment status and set parameters for real-time monitoring and operation, an input unit 4 to receive external start signals and trigger the driver to start working, and an output unit 5 to output fault signals for timely detection and handling of abnormal situations during equipment operation. A microprocessor 6 is connected to the power module 1, MODBUS-RTU communication interface 2, LCD screen 3, input unit 4, and output unit 5, respectively, to receive control commands, output fault signals based on the received information, and change the valve opening of the electronic expansion valve.

[0052] The MODBUS-RTU communication interface 2 communicates with the PLC or logic controller via the RS485 protocol, receiving opening control commands and uploading equipment status information. The MODBUS-RTU communication interface 2 acts as a bridge between the driver and the host computer, with one end connected to the host computer and the other end directly connected to the microprocessor 6. It transmits the electronic expansion valve opening control commands issued by the host computer to the microprocessor 6, and simultaneously uploads the equipment status information processed by the microprocessor 6 to the host computer, realizing remote control and status feedback. In one embodiment, this communication interface is implemented by an independent communication module, the core of which is an RS485 protocol chip.

[0053] The LCD screen 3 and the microprocessor 6 are bidirectionally connected. The microprocessor 6 sends the device's operating status and parameter information to the LCD screen 3 for display, making it convenient for users to view. Signals generated by the user's parameter setting operations through the LCD screen 3 are also transmitted back to the microprocessor 6, which processes and executes the corresponding actions.

[0054] The input unit 4 receives a low-level active start signal, triggering the microprocessor 6 to enter the operating mode. The input unit 4 is specifically designed to receive external start signals and is connected only to the microprocessor 6. Once an external start signal is received, the input unit 4 transmits the signal to the microprocessor 6, triggering the microprocessor 6 to begin executing subsequent control procedures, thus enabling the driver to start operating.

[0055] The output unit 5 includes normally open and normally closed relays for outputting alarm signals. The output unit 5 is connected to the microprocessor 6 and primarily receives fault signals from the microprocessor 6. When the microprocessor 6 detects an abnormality in the equipment's operation, it sends a fault signal to the output unit 5, which then transmits the signal to external devices for timely fault handling.

[0056] The microprocessor 6 serves as the core and connects to all other components. It receives the start signal from the input unit 4, processes the control commands transmitted from the MODBUS-RTU communication interface 2, controls the display content of the LCD screen 3 and receives user operation signals, sends fault signals to the output unit 5 based on the equipment's operating status, directly controls the opening of the electronic expansion valve, coordinates the work of various components, and ensures the normal operation of the driver.

[0057] The driver also supports an external UPS power supply to maintain the valve opening or close the valve after the main power supply fails.

[0058] The driver is compatible with electronic expansion valves of models DPFO, DPFQ, UKV, SKV, and PKV with a drive current of less than 1.2A.

[0059] In one embodiment, reference Figure 2 The diagram shows the terminal structure of the driver of this utility model, which includes a power input terminal (24V / 0V), a start signal input terminal (DI1 / GND1), an electronic expansion valve drive terminal (A / B / A- / B- / VM), a normally open relay alarm output terminal (95 / 98), a normally closed relay alarm output terminal (95 / 96), and an RS485 external communication interface (RS-A / RS-B).

[0060] During actual installation, connect the external power supply cable to the terminal (24V / 0V), the host computer communication cable to the terminal (RS-A / RS-B), and the motor cable of the electronic expansion valve to the terminal (A / B / A- / B- / VM) to complete the basic connection.

[0061] This utility model also discloses a heat pump device including the above-mentioned electronic expansion valve driver.

[0062] The detailed operating procedure of this electronic expansion valve actuator during the operation of the heat pump unit is as follows:

[0063] 1. Initialization Phase: After the driver is powered on, the power module starts working, converting the external power input into a stable 24V DC power supply to power the various components within the driver. The microprocessor (MCU / FPGA) starts up, performs internal initialization operations, and simultaneously initializes the LCD screen to display the initial interface. At this time, the input unit is in a state of waiting to receive an external start signal, the output unit outputs no fault signal, and the electronic expansion valve remains initially closed or at a specific default opening degree.

[0064] 2. Receiving a Start Signal: When an external device sends a start signal (e.g., an operator presses the start button, generating a low-level active trigger signal that meets the input unit's requirements), the input unit receives the signal and transmits it to the microprocessor. Upon receiving the start signal, the microprocessor enters normal operating mode, updates the display content on the LCD screen, and indicates that the system has started and is ready to receive control commands.

[0065] After the input unit triggers the driver to operate, the communication interface initializes and prepares to receive commands from the host computer. Control commands from the host computer enter the driver through this interface, driving the electronic expansion valve to operate. Simultaneously, the driver's status information is uploaded to the host computer via the communication interface. Therefore, the activation of the input unit is a prerequisite for the normal operation of the communication interface. The host computer controls the driver's operation through the communication interface, and the two establish an indirect connection through the communication interface.

[0066] 3. Communication Data Interaction: Upon startup, the driver's MODBUS-RTU communication interface begins data communication with the host computer (such as a PLC). Based on the operating requirements of the heat pump unit and real-time monitoring data, the host computer calculates the required opening value of the electronic expansion valve and sends the opening command to the driver via the MODBUS-RTU protocol. After receiving the command data, the driver's communication interface verifies and decodes the data to ensure its accuracy and integrity. Once verification is successful, the opening command is transmitted to the microprocessor.

[0067] 4. Control Signal Processing and Output: After receiving the opening command, the microprocessor further processes the command according to its internal preset control algorithm and logic. The microprocessor generates a corresponding control signal, which is sent to the drive circuit of the electronic expansion valve through the output unit to drive the stepper motor of the electronic expansion valve, thereby changing the opening degree of the electronic expansion valve.

[0068] 5. Equipment Status Monitoring and Feedback: During the operation of the electronic expansion valve, the actuator continuously monitors the equipment's operating status. Simultaneously, the microprocessor monitors the working status of its various components, such as whether the power supply voltage is normal and whether communication is stable. If any abnormality is detected, the microprocessor immediately performs fault diagnosis and handling.

[0069] The microprocessor will decide whether to stop the operation of the electronic expansion valve or take other safety protection measures based on the type of fault, such as closing the electronic expansion valve to a safe opening to prevent further damage to the equipment.

[0070] 6. Data display and parameter adjustment: During equipment operation, users can view the real-time operating parameters and operating status information of the equipment through the LCD screen of the operating driver.

[0071] The user-input adjustment commands are transmitted to the microprocessor via the LCD screen, and the microprocessor executes the commands accordingly.

[0072] 7. Shutdown Phase: When an external device sends a stop signal (e.g., an operator presses a stop button), the input unit receives the signal and transmits it to the microprocessor. Upon receiving the stop signal, the microprocessor controls the electronic expansion valve to gradually close to its initial state or a specific safe shut-off position. Simultaneously, the microprocessor ceases communication with the host computer and sets all components of the driver to low-power or standby mode to reduce energy consumption. Finally, the microprocessor displays a message indicating that the system has stopped operating on the LCD screen, awaiting the next startup command.

[0073] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An electronic expansion valve actuator, characterized in that, include: The power module provides a 24V DC power supply. The MODBUS-RTU communication interface is used for data communication with the host computer. An LCD screen is used to display device status and settings. The input unit receives an external start signal, triggering the driver to begin operation. The output unit is used to output fault signals; The microprocessor is connected to the power module, MODBUS-RTU communication interface, LCD display, input unit and output unit respectively, and is used to receive control commands, output fault signals and change the valve opening of the electronic expansion valve according to the received information.

2. The electronic expansion valve actuator according to claim 1, characterized in that, The MODBUS-RTU communication interface communicates with the PLC or logic controller via the RS485 protocol, receives opening control commands, and uploads equipment status information.

3. The electronic expansion valve actuator according to claim 1, characterized in that, The input unit receives a low-level active start signal, triggering the microprocessor to enter the working mode.

4. The electronic expansion valve actuator according to claim 1, characterized in that, The output unit includes normally open relays and normally closed relays, used to output alarm signals.

5. The electronic expansion valve actuator according to claim 1, characterized in that, The driver also supports an external UPS power supply to maintain the valve opening or close the valve after the main power supply fails.

6. The electronic expansion valve actuator according to claim 1, characterized in that, The driver supports electronic expansion valves of models DPFO, DPFQ, UKV, SKV, and PKV with a drive current of less than 1.2A.

7. A heat pump device, characterized in that, Includes the electronic expansion valve actuator as described in any one of claims 1 to 6.

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