Electronic expansion valve control circuit and refrigeration apparatus

Abstract

The utility model belongs to the technical field of electronic expansion valve control circuit, specifically relates to electronic expansion valve control circuit and refrigeration plant, electronic expansion valve control circuit includes mutually electric connection's MCU main module, drive module and electronic expansion valve, still includes current detection module and electric signal amplification module, current detection module is connected with being arranged between electronic expansion valve and power end or drive module and ground terminal, is used for detecting the electric signal change of drive module, the input of electric signal amplification module is electric connection with current detection module, the output of electric signal amplification module is electric connection with MCU main module, is used for amplifying the electric signal change, in the utility model, current detection module and current signal amplification module connect MCU main module, can monitor the abnormality and disconnect the corresponding module in time when the short circuit failure of inside coil of electronic expansion valve, avoids the fire risk caused by short circuit.

Description

Technical Field

[0001] This utility model belongs to the technical field of electronic expansion valve control circuit, specifically relating to electronic expansion valve control circuit and refrigeration equipment. Background Technology

[0002] Electronic expansion valve control circuits are commonly used to monitor and regulate the opening and flow of expansion valves. They can adjust the working state of expansion valves according to system requirements to ensure the stable operation of refrigeration equipment.

[0003] However, the electronic expansion valve control circuit design currently popular in the market has many drawbacks. In actual operation, the electronic expansion valve drive module only detects the voltage of one control coil, which can only detect when the electronic expansion valve is not connected, but cannot detect when the electronic expansion valve loses synchronization, phase loss or other abnormalities. In addition, detecting the voltage waveforms of four control coils at the same time can easily make the detection circuit too complicated and costly, and it cannot detect the internal short circuit of the electronic expansion valve coil.

[0004] Therefore, there is an urgent need for a simple and effective detection scheme to detect abnormalities and disconnect the corresponding circuit in a timely manner when a short circuit occurs in the coil inside the electronic expansion valve, so as to avoid fire caused by the burnout of electronic components in the electronic expansion valve itself or the drive module due to the short circuit. Utility Model Content

[0005] In order to overcome the shortcomings of the prior art, this utility model provides an electronic expansion valve control circuit and a refrigeration device to solve the problems of the prior art. When a short circuit fault occurs in the coil inside the electronic expansion valve, the abnormality is detected in time and the corresponding circuit is disconnected, so as to avoid fire caused by the electronic expansion valve itself or the electronic components in the drive module being burned out due to the short circuit.

[0006] One embodiment of this utility model provides an electronic expansion valve control circuit, including an MCU main module, a drive module, and an electronic expansion valve that are electrically connected to each other, and also includes a current detection module and an electrical signal amplification module:

[0007] The current detection module is connected between the electronic expansion valve and the power supply terminal, and the current detection module is configured to detect changes in the electrical signal of the electronic expansion valve; or, the current detection module is connected between the drive module and the ground terminal, and the current detection module is configured to detect changes in the electrical signal of the drive module.

[0008] The input terminal of the electrical signal amplification module is electrically connected to the current detection module, and the output terminal of the electrical signal amplification module is electrically connected to the MCU main module. The electrical signal amplification module is configured to amplify the changes in the electrical signal output by the current detection module.

[0009] The MCU main module is configured to detect the operating status of the electronic expansion valve based on the comparison result of the change in electrical signal with a preset value; and to output a drive signal or a shut-off signal to the drive module to make the electronic expansion valve operate or shut down.

[0010] In one embodiment of this utility model, a conversion module is further included. The conversion module is connected between the output terminal of the electrical signal amplification module and the control unit of the MCU main module. The conversion module is configured to convert the electrical signal amplified by the electrical signal amplification module.

[0011] In one embodiment of this utility model, when the current detection module is connected between the electronic expansion valve and the power supply, the current detection module is provided with a sensing resistor, which is configured to detect the current change of the electronic expansion valve.

[0012] In one embodiment of this utility model, the electrical signal amplification module includes an operational amplifier circuit.

[0013] In one embodiment of this utility model, when the current detection module is connected between the electronic expansion valve and the power supply, the current detection module is equipped with a Hall sensor, which is configured to detect the current change of the electronic expansion valve.

[0014] In one embodiment of this utility model, when the current detection module is connected between the drive module and the ground terminal, the current detection module is provided with a sensing resistor, which is configured to detect the current change of the drive module.

[0015] In one embodiment of this utility model, the electrical signal amplification module includes an operational amplifier circuit.

[0016] In one embodiment of this utility model, an alarm device is also included. The alarm device is connected to the MCU main module and is configured to issue an alarm when the electronic expansion valve is closed.

[0017] One embodiment of this utility model also discloses a refrigeration device, including an electronic expansion valve control circuit as described in any of the above embodiments.

[0018] The electronic expansion valve control circuit and refrigeration equipment provided by this utility model can achieve the following technical effects:

[0019] 1. The current detection module and the current signal amplification circuit are connected to the MCU main module. When a short circuit fault occurs in the coil inside the electronic expansion valve, the abnormality can be detected in time and the corresponding circuit can be disconnected to avoid fire caused by the electronic expansion valve itself or the electronic components in the drive module burning out due to the short circuit.

[0020] 2. Utilizing the detection function of the current detection module, the MCU control unit can quickly and accurately determine whether the electronic expansion valve is properly connected, avoiding the occurrence of disconnection or phase loss problems; the current detection module is connected to the MCU main module with the current signal amplification circuit, which can monitor the operating current of the electronic expansion valve in real time, ensuring that the operating current of the electronic expansion valve operates within the normal range.

[0021] 3. When the detection element is a resistive sensor, the current detection module can be connected between the electronic expansion valve and the power supply terminal. Combined with an electrical signal amplification module using other devices with symmetrical dual input resistors or operational amplifier circuits, high-precision detection can be achieved, suitable for applications requiring high detection accuracy. Alternatively, when the detection element is a resistive sensor or a Hall sensor, the current detection module can be connected between the drive module and the ground terminal. Combined with an input resistor connected to the non-inverting input terminal of the operational amplifier, and the inverting input terminal of the operational amplifier connected to the ground terminal of the electrical signal amplification module, qualitative anomaly detection can be achieved. This method has low hardware cost and is suitable for applications requiring conventional detection accuracy. Attached Figure Description

[0022] 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 the structures shown in these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the electronic expansion valve control circuit structure according to one embodiment of the present invention;

[0024] Figure 2 A schematic diagram illustrating the electronic expansion valve control circuit structure including a sensing resistor according to this utility model.

[0025] Figure 3 This diagram illustrates the structure of the electronic expansion valve control circuit of this invention, which includes a Hall sensor.

[0026] The symbols in the attached image are explained as follows:

[0027] 1-Current detection module; 11-Sensing resistor; 12-Hall sensor;

[0028] 2-Electronic signal amplification module;

[0029] 3-Driver module;

[0030] 4-MCU main module; 41-Conversion module; 42-Control unit;

[0031] 5-Electronic expansion valve;

[0032] 6-Pulse voltage detection circuit. Detailed Implementation

[0033] The technical solutions of the present utility model 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 utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] Understandably, electronic expansion valves may experience abnormalities during operation, such as step loss, excessive current, and coil short circuit. Step loss refers to the phenomenon where, due to various reasons, the rotor fails to move to the predetermined position according to the pulse signal sent by the MCU controller during operation. Excessive current refers to the current flowing through the electronic expansion valve drive module or stepper motor coil exceeding its rated value or normal operating current range. Coil short circuit refers to an abnormally low resistance connection inside the stepper motor coil or between it and external circuitry, causing the current to bypass the normal path and directly form a short circuit loop. When these abnormalities occur, the current changes in the power supply circuit of the electronic expansion valve will be abnormal.

[0035] Please refer to Figures 1-3 One embodiment of this utility model provides an electronic expansion valve control circuit, including an MCU main module 4, a drive module 3, and an electronic expansion valve 5 that are electrically connected to each other, and also includes a current detection module 1 and an electrical signal amplification module 2.

[0036] The current detection module 1 is connected between the electronic expansion valve 5 and the power supply terminal, and the current detection module 1 is configured to detect changes in the electrical signal of the electronic expansion valve 5; or, the current detection module 1 is connected between the drive module 3 and the ground terminal, and the current detection module 1 is configured to detect changes in the electrical signal of the drive module 3.

[0037] The input terminal of the electrical signal amplification module 2 is electrically connected to the current detection module 1, and the output terminal of the electrical signal amplification module 2 is electrically connected to the MCU main module 4. The electrical signal amplification module 2 is configured to amplify the changes in the electrical signal output by the current detection module 1.

[0038] The MCU main module 4 is configured to output a drive signal or a shut-off signal to the drive module 3 based on the comparison result of the electrical signal change and the preset value, so as to make the electronic expansion valve 5 operate or shut down.

[0039] Understandably, in this embodiment, in the field of electronic expansion valve control circuit technology, the MCU main module 4 digitizes the acquired analog signal using existing analog-to-digital conversion algorithms, converting it into a digital signal that is easy to calculate and analyze. It then calculates and determines whether the electronic expansion valve is out of sync or whether the electronic expansion valve coil is abnormal (e.g., coil detachment, internal short circuit, open circuit, excessively high power supply voltage to the electronic expansion valve coil). Based on the compressor system's requirements, the MCU main module 4 outputs a PWM control signal to the drive module 3 of the electronic expansion valve 5. The drive module 3 can flexibly switch the current direction of the electronic expansion valve coil winding according to the input PWM control signal, realizing the forward and reverse rotation and precise step control of the electronic expansion valve 5, thereby adjusting the valve opening. In actual circuit design, suitable power transistors and drive chips, such as the common ULN2003, can be selected to ensure that the electronic expansion valve 5 drive module 3 has sufficient driving capability and stability, reliably driving the electronic expansion valve 5 to meet the operating requirements under different working conditions.

[0040] In one embodiment, the logic for detecting excessively high voltage is as follows: Given a fixed electronic expansion valve coil, its coil impedance Z is also fixed, and the coil current I = U / Z; when the voltage increases, the current I increases. The dangers of high voltage are: the voltage exceeds the rated voltage of the electronic expansion valve, the current flowing through the electronic expansion valve coil will be relatively large, the electronic expansion valve coil will overheat severely, and may even melt, ultimately leading to a fire. This embodiment solves the problem of excessively high voltage causing severe overheating of the electronic expansion valve coil by detecting the coil current.

[0041] The current detection module 1 is used to detect changes in the electrical signal of the drive module 3, mainly changes in current. The current detection module 1 includes a detection element and wires connected to the positive and negative terminals of the detection element. The current sampling circuit monitors the operating current of the electronic expansion valve 5 in real time. The detection element can be either a Hall effect sensor or a detection resistor, selected according to the actual application scenario and accuracy requirements. In terms of circuit connection, the current detection module 1 is connected in series in the power supply circuit of the electronic expansion valve 5. The collected current signal is transmitted to the electrical signal amplification module 2, which is used to amplify the changes in electrical signal, mainly the current.

[0042] The preset value for current variation can be set by engineers based on design requirements and historical experience, and can be a fixed value or a variation range.

[0043] The electronic expansion valve control circuit of this embodiment can achieve the following technical effects:

[0044] When a short circuit fault occurs in the coil inside the electronic expansion valve 5, the abnormality can be detected in time and the corresponding circuit can be disconnected to avoid fire caused by the electronic expansion valve 5 itself or the electronic components in the drive module 3 burning out due to the short circuit.

[0045] Using the detection function of the current detection module 1, the MCU control unit 42 can quickly and accurately determine whether the electronic expansion valve 5 is properly connected, thus avoiding the occurrence of disconnection or phase loss problems. The current detection module 1 is connected to the current signal amplification circuit of the MCU main module 4, which can monitor the operating current of the electronic expansion valve 5 in real time to ensure that the operating current of the electronic expansion valve 5 operates within the normal range.

[0046] In one embodiment of this utility model, a conversion module 41 is also included. The conversion module 41 is connected between the output terminal of the electrical signal amplification module 2 and the control unit 42 of the MCU main module 4. The conversion module 41 is configured to convert the electrical signal amplified by the electrical signal amplification module 2.

[0047] Understandably, the conversion module 41 is used to further filter and level-convert the amplified current signal so that it meets the input requirements of the control unit 42 of the MCU main module 4, so that the MCU main module 4 can perform accurate analysis and judgment.

[0048] Please refer to Figure 1 In one embodiment of this utility model, when the current detection module 1 is connected between the electronic expansion valve 5 and the power supply terminal, the current detection module 1 is provided with a sensing resistor 11, which is configured to detect the current change of the electronic expansion valve 5.

[0049] The operational amplifier circuit includes an operational amplifier, input resistors R1 and R2, and capacitor C1. The two input resistors are respectively connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier.

[0050] Understandably, when the sensing element is a sensing resistor 11, the current sensing module 1 can be connected and set between the electronic expansion valve 5 and the power supply terminal. In conjunction with the electrical signal amplification module 2 with symmetrical dual input resistors, a high-precision detection effect can be achieved, which is suitable for occasions with high detection accuracy requirements.

[0051] Please refer to Figures 2-3In one embodiment of this utility model, when the current detection module 1 is connected between the electronic expansion valve 5 and the power supply terminal, the current detection module 1 is equipped with a Hall sensor 12, which is configured to detect the current change of the electronic expansion valve 5.

[0052] Alternatively, when the current detection module 1 is connected between the drive module 3 and the ground terminal, the current detection module 1 is provided with a sensing resistor 11, which is configured to detect the current change of the drive module 3.

[0053] The operational amplifier circuit includes an operational amplifier and an input resistor R1. The input resistor R1 is connected to the non-inverting input terminal of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to the ground terminal of the electrical signal amplification module 2.

[0054] Understandably, when the detection element is a sensing resistor 11 or a Hall sensor 12, and the current detection module 1 is connected between the drive module 3 and the ground terminal, the input resistor R1 is connected to the non-inverting input terminal of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to the ground terminal of the electrical signal amplification module 2, so as to achieve a qualitative abnormality detection effect, with low hardware cost and suitable for occasions with conventional detection accuracy requirements.

[0055] In one embodiment of this utility model, an alarm device is also included. The alarm device is connected to the MCU main module 4 and is configured to issue an alarm when the electronic expansion valve 5 is closed.

[0056] Understandably, this embodiment issues alarm information via a display screen or alarm device to prompt users or maintenance personnel to perform inspection and repair. Furthermore, the control unit 42 of the MCU main module 4 can be connected to a memory to record information such as the time and type of the fault, facilitating subsequent fault analysis and equipment maintenance.

[0057] One embodiment of this utility model also discloses a refrigeration device, including an electronic expansion valve control circuit as described in any of the above embodiments.

[0058] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An electronic expansion valve control circuit, comprising an MCU main module (4), a drive module (3), and an electronic expansion valve (5) electrically connected to each other, characterized in that, It also includes a current detection module (1) and an electrical signal amplification module (2): The current detection module (1) is connected between the electronic expansion valve (5) and the power supply terminal, and the current detection module (1) is configured to detect the change in the electrical signal of the electronic expansion valve (5); or, the current detection module (1) is connected between the drive module (3) and the ground terminal, and the current detection module (1) is configured to detect the change in the electrical signal of the drive module (3); The input terminal of the electrical signal amplification module (2) is electrically connected to the current detection module (1), and the output terminal of the electrical signal amplification module (2) is electrically connected to the MCU main module (4). The electrical signal amplification module (2) is configured to amplify the changes in the electrical signal output by the current detection module (1). The MCU main module (4) is configured to output a drive signal or a shut-off signal to the drive module (3) based on the comparison result of the change of electrical signal with a preset value, so as to make the electronic expansion valve (5) run or shut down.

2. The electronic expansion valve control circuit as described in claim 1, characterized in that, It also includes a conversion module (41), which is connected between the output of the electrical signal amplification module (2) and the control unit (42) of the MCU main module (4). The conversion module (41) is configured to convert the electrical signal amplified by the electrical signal amplification module (2).

3. The electronic expansion valve control circuit as described in claim 2, characterized in that, When the current detection module (1) is connected between the electronic expansion valve (5) and the power supply, the current detection module (1) is provided with a sensing resistor (11), which is configured to detect the current change of the electronic expansion valve (5).

4. The electronic expansion valve control circuit as described in claim 3, characterized in that, The electrical signal amplification module (2) includes an operational amplifier circuit.

5. The electronic expansion valve control circuit as described in claim 2, characterized in that, When the current detection module (1) is connected between the electronic expansion valve (5) and the power supply, the current detection module (1) is equipped with a Hall sensor (12), which is configured to detect the current change of the electronic expansion valve (5).

6. The electronic expansion valve control circuit as described in claim 2, characterized in that, When the current detection module (1) is connected between the drive module (3) and the ground terminal, the current detection module (1) is provided with a sensing resistor (11), which is configured to detect the current change of the drive module (3).

7. The electronic expansion valve control circuit as described in claim 5 or 6, characterized in that, The electrical signal amplification module (2) includes an operational amplifier circuit.

8. The electronic expansion valve control circuit as described in claim 7, characterized in that, It also includes an alarm device connected to the MCU main module (4) and configured to issue an alarm when the electronic expansion valve (5) is closed.

9. A refrigeration device, characterized in that, Includes the electronic expansion valve control circuit as described in any one of claims 1-8.

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