CN114278735A

CN114278735A - Control system and control method for electronic expansion valve

Info

Publication number: CN114278735A
Application number: CN202011040478.9A
Authority: CN
Inventors: 闫冰; 范春丽; 何继富
Original assignee: Emerson Climate Technologies Suzhou Co Ltd
Current assignee: Copeland Suzhou Co Ltd
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2022-04-05
Anticipated expiration: 2040-09-28
Also published as: WO2022062128A1; CN114278735B

Abstract

The present application provides control systems and control methods for electronic expansion valves. The electronic expansion valve includes a valve member including a valve body and a valve spool movable relative to the valve body, and a motor configured to move the valve spool to open or close the electronic expansion valve. The control system includes: a power supply device configured to supply power to the motor; and a control device that includes a first mode and a second mode for a mode of driving the motor, wherein a current required to drive the motor in the first mode is smaller than a current required to drive the motor in the second mode. The control device is configured to selectively drive the motor in the first mode or the second mode according to preset motor drive related parameters when the electronic expansion valve is activated.

Description

Control system and control method for electronic expansion valve

Technical Field

The present disclosure relates to a control system for an electronic expansion valve and a control method for an electronic expansion valve.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

An electronic expansion valve including a valve member and a stepping motor is known. The valve member includes a fixed valve body and a valve core movable relative to the valve body. When the stepping motor is driven by electricity, the rotor rotates relative to the stator, and then the rotor drives the valve core to move so as to open or close the electronic expansion valve.

The stepping motor is usually supplied with dc power and driven by means of a switching power supply. At present, in order to achieve the purpose of accurate control, a large current is often required for driving a stepping motor. However, in some cases, for example, in the case where the input voltage of the switching power supply is too low or the ambient temperature is too low, the switching power supply may not satisfy the current demand of the stepping motor, or may not output normally because the current demand of the stepping motor is too large.

Accordingly, there is a need in the art for a system and method that can safely and reliably control an electronic expansion valve.

Disclosure of Invention

It is an object of the present disclosure to provide a system and method that enables safe and reliable control of an electronic expansion valve.

It is another object of the present disclosure to provide a control system and control method for an electronic expansion valve that is relatively low cost.

According to one aspect of the present disclosure, a control system for an electronic expansion valve is provided. The electronic expansion valve includes a valve member including a valve body and a valve spool movable relative to the valve body, and a motor configured to move the valve spool to open or close the electronic expansion valve. The control system includes: a power supply device configured to supply power to the motor; and a control device that includes a first mode and a second mode for a mode of driving the motor, wherein a current required to drive the motor in the first mode is smaller than a current required to drive the motor in the second mode. The control device is configured to selectively drive the motor in a first mode or a second mode according to preset motor drive related parameters when the electronic expansion valve is activated.

The control system for an electronic expansion valve of the present application may selectively drive the motor in a first mode (e.g., full-step drive with lower current demand) or a second mode (e.g., half-step drive with higher current demand) depending on a parameter related to the operation or driving of the motor (e.g., input voltage of a power supply device, ambient temperature, or driving time of the motor, etc.) when activating the electronic control valve. Therefore, the problem that the normal driving cannot be realized due to low supply current can be solved, and high-precision control can be realized when the current requirement is met.

Further, the control system for an electronic expansion valve according to the present disclosure only requires the addition of a detection circuit including several resistors and detection devices, and thus the added cost is low, while the development period can be reduced.

In some embodiments, the preset motor drive related parameter comprises an input voltage of the power supply device. The control system further includes a voltage detection device configured to detect an input voltage of the power supply device. The control device drives the motor in the first mode or the second mode according to the input voltage.

In some embodiments, the control device is configured to: the control means drives the motor in the first mode when the detected input voltage is lower than a first voltage predetermined value; the control device drives the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value, which is larger than the first voltage predetermined value; and the control means drives the motor in the present mode when the detected input voltage is equal to or greater than the first voltage predetermined value but equal to or less than the second voltage predetermined value.

In some embodiments, the control system further comprises a negative temperature coefficient resistance disposed at an input side of the power supply device.

In some embodiments, the predetermined motor drive related parameter comprises an ambient temperature of the negative temperature coefficient resistance. The control system further includes a temperature sensing device configured to sense an ambient temperature of the negative temperature coefficient of resistance.

In some embodiments, the control device is configured to: the control device drives the motor in the first mode when the detected ambient temperature is lower than a first temperature predetermined value; the control means drives the motor in the second mode when the detected ambient temperature is higher than a second predetermined temperature value, which is greater than the first predetermined temperature value; and when the detected ambient temperature is greater than or equal to the first temperature preset value but less than or equal to the second temperature preset value, the control device drives the motor in the current mode.

In some embodiments, the preset motor drive related parameters include an input voltage of the power supply device and an ambient temperature of the negative temperature coefficient resistor. The control system further comprises: a voltage detection device configured to detect an input voltage of the power supply device; and a temperature detection device configured to detect an ambient temperature of the negative temperature coefficient resistance.

In some embodiments, the control device is configured to: the control means drives the motor in the first mode when the detected input voltage is lower than a first voltage predetermined value and the detected ambient temperature is lower than a first temperature predetermined value; the control means drives the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value and the detected ambient temperature is higher than a second temperature predetermined value, wherein the second voltage predetermined value is larger than the first voltage predetermined value and the second temperature predetermined value is larger than the first temperature predetermined value; and the control means drives the motor in the present mode when the detected input voltage is equal to or greater than the first voltage predetermined value but equal to or less than the second voltage predetermined value and the detected ambient temperature is equal to or greater than the first temperature predetermined value but equal to or less than the second temperature predetermined value.

In some embodiments, the control system further comprises a timer for measuring a driving time of the first mode. The control system is configured to select to drive the motor in the first mode upon activation of the electronic expansion valve. The preset motor drive related parameter includes a drive time for the motor drive in the first mode. And switching to the second mode when the driving time reaches a set time.

In some embodiments, the motor is a stepper motor, the power supply device is a switching power supply, the first mode is a full-step drive mode, and the second mode is a half-step drive mode.

According to one aspect of the present disclosure, a control method for an electronic expansion valve is provided. The electronic expansion valve includes a valve member including a valve body and a valve spool movable relative to the valve body, and a motor configured to move the valve spool to open or close the electronic expansion valve. The control method comprises the following steps: acquiring a parameter related to driving of the motor; supplying power to the motor by a power supply device to drive the motor, wherein the motor is selected to be driven in a first mode or a second mode according to the parameter, and the current required for driving the motor in the first mode is less than the current required for driving the motor in the second mode.

This control method has similar advantages to the control system described above.

In some embodiments, acquiring the parameter related to the driving of the motor includes detecting an input voltage of the power supply device, and selecting to drive the motor in the first mode or the second mode according to the detected input voltage.

In some embodiments, when the detected input voltage is lower than a first voltage by a predetermined value, selecting to drive the motor in the first mode; selecting to drive the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value, the second voltage predetermined value being greater than the first voltage predetermined value; and maintaining a current mode to drive the motor when the detected input voltage is equal to or greater than the first voltage predetermined value but equal to or less than the second voltage predetermined value.

In some embodiments, the control method further comprises providing a negative temperature coefficient resistance at an input side of the power supply device.

In some embodiments, obtaining a parameter related to driving of the motor includes detecting an ambient temperature of the negative temperature coefficient resistance, and selecting to drive the motor in the first mode or the second mode according to the detected ambient temperature.

In some embodiments, the control method further comprises: selecting to drive the motor in the first mode when the detected ambient temperature is lower than a first temperature predetermined value; selecting to drive the motor in the second mode when the detected ambient temperature is higher than a second predetermined temperature value, the second predetermined temperature value being greater than the first predetermined temperature value; and maintaining the current mode to drive the motor when the detected ambient temperature is greater than or equal to the first temperature predetermined value but less than or equal to the second temperature predetermined value.

In some embodiments, obtaining the parameter related to the driving of the motor includes detecting an input voltage of the power supply device, detecting an ambient temperature of the negative temperature coefficient resistance, and selecting to drive the motor in the first mode or the second mode according to the detected input voltage and the ambient temperature.

In some embodiments, the control method further comprises: selecting to drive the motor in the first mode when the detected input voltage is lower than a first voltage predetermined value and the detected ambient temperature is lower than a first temperature predetermined value; selecting to drive the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value or the detected ambient temperature is higher than a second temperature predetermined value, wherein the second voltage predetermined value is greater than the first voltage predetermined value and the second temperature predetermined value is greater than the first temperature predetermined value; and maintaining a current mode to drive the motor when the detected input voltage is equal to or greater than the first voltage predetermined value but equal to or less than the second voltage predetermined value and the detected ambient temperature is equal to or greater than the first temperature predetermined value but equal to or less than the second temperature predetermined value.

In some embodiments, selecting to drive the motor in the first mode when the electronic expansion valve is activated, acquiring a parameter related to the driving of the motor includes measuring a driving time of the first mode, and switching to the second mode when the driving time reaches a set time.

In some embodiments, the control method further comprises: when starting to drive the motor, it is first determined whether the current mode is the first mode or the second mode.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the specific examples and embodiments described in this section are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

Drawings

The features and advantages of one or more embodiments of the present disclosure will become more readily understood from the following description with reference to the accompanying drawings, in which:

fig. 1 is a schematic cross-sectional view of an electronic expansion valve;

FIG. 2 is a schematic functional block diagram of a control system for an electronic expansion valve according to a first embodiment of the present disclosure;

FIG. 3 is a flow chart schematic of a control method of the control system of FIG. 2;

FIG. 4 is a schematic functional block diagram of a control system for an electronic expansion valve according to a second embodiment of the present disclosure;

FIG. 5 is a flow chart schematic of a control method of the control system of FIG. 4;

FIG. 6 is a schematic functional block diagram of a control system for an electronic expansion valve according to a third embodiment of the present disclosure;

FIG. 7 is a flow chart schematic of a control method of the control system of FIG. 6;

FIG. 8 is a schematic functional block diagram of a control system for an electronic expansion valve according to a fourth embodiment of the present disclosure; and

fig. 9 is a flowchart illustrating a control method of the control system of fig. 8.

It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

Detailed Description

Exemplary embodiments of the present application will now be described more fully with reference to the accompanying drawings.

The exemplary embodiments are provided so that this disclosure will be thorough and will more fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The structure of the electronic expansion valve 10 is described below with reference to fig. 1. As shown in fig. 1, the electronic expansion valve 10 includes a valve member 11 communicating

fluid conduits

20 and 30, and a motor 13 driving the valve member 11 in an open state or a closed state.

The valve member 11 includes a fixed valve body 11a and a valve spool 11b movable relative to the valve body 11 a. The valve body 11a has a valve hole 12 formed therein. When the valve spool 11b moves away from the valve hole 12, the electronic expansion valve 10 is opened to allow fluid to flow between the

fluid conduits

20 and 30; when the valve spool 11b moves toward the valve hole 12, the electronic expansion valve 10 is closed to prevent fluid from flowing between the

fluid conduits

20 and 30.

The motor 13 includes a fixed stator 13a and a rotor 13b movable relative to the stator 13 a. The stator 13a is fixed to the valve body 11a, and the rotor 13b is coupled to the valve spool 11 b. The motor 13 is connected to a power supply device (not shown) through a cable 40. When the power supply device supplies power to the motor 13, current passes through the windings 14 of the stator 13a of the motor 13, thereby generating a magnetic field that causes the rotor 13b to rotate relative to the stator 13 a. The rotation of the rotor 13b causes the valve spool 11b to move away from the valve hole 12 or toward the valve hole 12 to open or close the electronic expansion valve 10.

The motor 13 may be, for example, a stepper motor. In order for the rotor 13b of the motor 13 to rotate continuously and smoothly, the stator must produce a continuous, even magnetic field. The strength and direction of the magnetic field of the stator 13a of the motor 13 is determined and proportional by the resultant current of the stator 13 a. That is, the motor 13 can be driven by controlling the current of the stator 13a of the motor 13.

The driving of the stepping motor includes full-step driving and half-step driving. The accuracy of full-step driving is low and the required current is small, while the accuracy of half-step driving is high and the required current is large. Generally, to achieve a high control accuracy, a half-step driving method is used to drive the stepping motor.

However, for example, in the case where the input voltage of the power supply device is too low, the current demand of the stepping motor may not be satisfied, or the current demand of the stepping motor may be too large to be normally output. For example, in the case where a Negative Temperature Coefficient (NTC) resistor is provided to suppress the input terminal of the power supply device from being impacted by the surge current, when the ambient temperature is low, the resistance value of the negative temperature coefficient resistor increases, resulting in a decrease in the voltage of the input terminal of the power supply device. Therefore, the power supply device may not satisfy the current demand of the stepping motor, or may not output normally because the current demand of the stepping motor is too large.

The control system and the control method for an electronic expansion valve according to the present disclosure can safely and reliably drive a motor in a first mode (e.g., full-step driving) in which a current required to drive the motor is smaller than a current required to drive the motor in a second mode (e.g., half-step driving) or selectively drive the motor in the first mode or the second mode (e.g., half-step driving) according to preset motor drive-related parameters (e.g., an input voltage of a power supply device, an ambient temperature, or a driving time of the motor, etc.) at the time of starting the electronic expansion valve. Therefore, the problem that the normal driving cannot be realized due to low supply current can be solved, and high-precision control can be realized when the current requirement is met.

A control system and a control method for an electronic expansion valve according to various embodiments of the present disclosure will be described below with reference to the accompanying drawings.

< first embodiment >

Fig. 2 is a schematic functional block diagram of a control system for an electronic expansion valve according to a first embodiment of the present disclosure. As shown in fig. 2, the control system according to the first embodiment includes: a switching power supply 120 for supplying a dc power to the stepping motor 110 of the electronic expansion valve; a voltage detection device 140 for detecting an input voltage at an input terminal of the switching power supply 120; and a control device 130 for driving the stepping motor 110 in a full-step driving mode or a half-step driving mode according to the detected input voltage. The current required to drive the stepping motor 110 in the full-step driving mode is smaller than the current required to drive the stepping motor 110 in the half-step driving mode.

The switching power supply 120 is an example of the above power supply device. If the input voltage of the switching power supply 120 is low, the full-step driving mode may be selected to drive the stepping motor 110. At this time, even if the current supplied to the stepping motor 110 is reduced because the input voltage is low, the current demand can be satisfied because the current required for the full-step driving mode is small. If the input voltage of the switching power supply 120 is high, a half-step driving mode may be selected to achieve precise operation of the electronic expansion valve. At this time, since the current supplied to the stepping motor 110 can satisfy the requirement of the half-step driving, the precise driving mode can be selected to achieve a better operation effect of the electronic expansion valve.

Fig. 3 is a flow chart diagram of a control method of the control system of fig. 2. A control method of the control system of fig. 2 is described below with reference to fig. 3.

As shown in fig. 3, the electronic expansion valve is started, i.e., energized to the electronic expansion valve (specifically, the stepping motor 110), and the electronic expansion valve is reset to then drive the stepping motor 110 and move the valve spool in step S00. After the electronic expansion valve is started, driving of the stepping motor 110 is started at step S01. Next, it is determined at step S02 whether the current driving mode is the full-step driving mode.

If it is determined in step S02 that the current driving mode is not the full-step driving mode (i.e., the half-step driving mode), it proceeds to step S110 to compare the input voltage U detected by the voltage detecting device 140 with the first voltage predetermined value U1. The first predetermined voltage value U1 may be set according to the requirements of half-step driving and full-step driving of the stepping motor 110. In other words, when the input voltage is lower than the first voltage by a predetermined value, the requirement of the half-step driving cannot be satisfied.

When it is determined in step S110 that the input voltage U is less than the first voltage predetermined value U1, the current driving mode (half-step driving mode) is switched to the full-step driving mode in step S111 because it cannot satisfy the requirement of the half-step driving. When the input voltage U is not less than the first voltage predetermined value U1, the current driving mode is maintained in the half-step driving mode, see step S122.

If it is determined in step S02 that the current driving mode is the full-step driving mode, it goes to step S120 to compare the input voltage U detected by the voltage detecting means 140 with the second voltage predetermined value U2, wherein the second voltage predetermined value U2 is greater than the first voltage predetermined value U1. Similarly, the second predetermined voltage value U2 may be set according to the requirements of half-step driving and full-step driving of the stepping motor 110. In other words, when the input voltage is higher than the second voltage predetermined value, stable driving of the stepping motor in the half-step driving mode can be ensured.

When it is determined in step S120 that the input voltage U is greater than the second voltage predetermined value U2, the current driving mode (full-step driving mode) is switched to the half-step driving mode in step S121 because it can fully satisfy the requirement of the half-step driving. When the input voltage U is not higher than the second voltage predetermined value U2, the current driving mode is maintained in the full-step driving mode, see step S112.

The driving manner in steps S112 and S122 may continue until the driving of the electronic expansion valve is finished (see step S10).

The control system and the control method for an electronic expansion valve according to the first embodiment actively detect the input voltage of the input terminal of the switching power supply when the electronic expansion valve is activated and can determine the driving manner of the stepping motor according to the detected input voltage. That is, when the input voltage is low, the stepping motor can be driven in a full-step driving manner, thereby avoiding a situation in which the normal driving cannot be performed due to insufficient current. When the input voltage is high, the stepping motor can be driven in a half-step driving manner, thereby achieving high-precision operation.

< second embodiment >

Fig. 4 is a schematic functional block diagram of a control system for an electronic expansion valve according to a second embodiment of the present disclosure. As shown in fig. 4, the control system according to the second embodiment includes: a switching power supply 220 for supplying a dc power to the stepping motor 210 of the electronic expansion valve; a Negative Temperature Coefficient (NTC) resistor 250 for suppressing the input terminal of the switching power supply 220 from being impacted by the inrush current; a temperature detecting means 260 for detecting an ambient temperature of the negative temperature coefficient resistor 250; and a control device 230 for driving the stepping motor 210 in a full-step driving mode or a half-step driving mode according to the detected ambient temperature.

In the control system of the second embodiment, a negative temperature coefficient resistor 250 is generally provided at the input terminal of the switching power supply 220 to protect the circuit. As described above, when the ambient temperature is low, the resistance of the ntc resistor 250 increases, resulting in a decrease in the input voltage at the input terminal of the switching power supply 220. As such, the switching power supply 220 may not meet the current demand of the stepping motor, or may not output normally because the current demand of the stepping motor is too large. Therefore, in the control system of the second embodiment, the stepping motor is driven in the full-step driving mode or the half-step driving mode selected in accordance with the ambient temperature to achieve safe and reliable operation.

Fig. 5 is a flow chart diagram of a control method of the control system of fig. 4. A control method of the control system of fig. 4 is described below with reference to fig. 5.

Steps S00, S01, S02, and S10 in fig. 5 are the same as those in fig. 3, and are not described in detail here. The following mainly describes the steps in fig. 5 different from fig. 3.

It is determined at step S02 whether the current driving mode is the full-step driving mode. If it is determined in step S02 that the current driving mode is not the full-step driving mode (i.e., the half-step driving mode), it proceeds to step S210 to compare the ambient temperature T detected by the temperature detecting means 260 with the first temperature predetermined value T1. The first predetermined temperature value T1 may be set according to the requirements of the half-step driving and the full-step driving of the stepping motor 210. In other words, when the ambient temperature T is lower than the first predetermined temperature T1, the requirement for the half-step driving will not be satisfied.

When it is determined in step S210 that the ambient temperature T is less than the first predetermined temperature T1, the current driving mode (half-step driving mode) is switched to the full-step driving mode in step S211 because it cannot satisfy the requirement of the half-step driving. When the ambient temperature T is not less than the first predetermined temperature T1, the current driving mode is maintained in the half-step driving mode, see step S222.

If it is determined in step S02 that the current driving mode is the full-step driving mode, it goes to step S220 to compare the ambient temperature T detected by the temperature detecting means 260 with a second predetermined temperature value T2, wherein the second predetermined temperature value T2 is greater than the first predetermined temperature value T1. Similarly, the second predetermined temperature value T2 may be set according to the requirements of the half-step driving and the full-step driving of the stepping motor 210. In other words, when the ambient temperature T is higher than the second predetermined temperature T2, stable driving of the stepping motor in the half-step driving mode can be ensured.

When it is determined in step S220 that the ambient temperature T is greater than the second predetermined temperature value T2, the current driving mode (full-step driving mode) is switched to the half-step driving mode in step S221 because it can fully satisfy the requirement of the half-step driving. When the ambient temperature T is not higher than the second temperature predetermined value T2, the current driving mode is maintained in the full-step driving mode, see step S212.

The driving manner in steps S212 and S222 may continue until the driving of the electronic expansion valve is finished (see step S10).

The control system and the control method for an electronic expansion valve according to the second embodiment actively detect the ambient temperature of the negative temperature coefficient resistor at the time of starting the electronic expansion valve and can determine the driving manner of the stepping motor according to the detected ambient temperature. That is, when the ambient temperature is low, the stepping motor can be driven in a full-step driving manner, thereby avoiding a situation in which the normal driving cannot be performed due to insufficient current. When the ambient temperature is high, the stepping motor can be driven in a half-step driving manner, thereby achieving high-precision operation.

< third embodiment >

Fig. 6 is a schematic functional block diagram of a control system for an electronic expansion valve according to a third embodiment of the present disclosure. As shown in fig. 6, the control system according to the third embodiment includes: a switching power supply 320 for supplying a dc power to the stepping motor 310 of the electronic expansion valve; a voltage detection device 340 for detecting an input voltage at an input terminal of the switching power supply 320; a Negative Temperature Coefficient (NTC) resistor 350 for suppressing surge current from being applied to the input terminal of the switching power supply 320; a temperature detection means 360 for detecting an ambient temperature of the negative temperature coefficient resistor 350; and a control means 330 for driving the stepping motor 310 in a full-step driving mode or a half-step driving mode according to the detected input voltage and ambient temperature.

In the control system of the third embodiment, the driving condition of the stepping motor is judged more accurately by detecting the input voltage of the switching power supply and the ambient temperature of the negative temperature coefficient resistor, so that an appropriate driving manner is selected, and thus the normal driving of the stepping motor is ensured.

Fig. 7 is a flow chart diagram of a control method of the control system of fig. 6. A control method of the control system of fig. 6 is described below with reference to fig. 7.

Steps S00, S01, S02, and S10 in fig. 7 are the same as those in fig. 3, and are not described in detail here. The following mainly describes the steps in fig. 7 different from fig. 3.

It is determined at step S02 whether the current driving mode is the full-step driving mode. If it is determined in step S02 that the current driving mode is not the full-step driving mode (i.e., the half-step driving mode), it proceeds to step S310 to compare the input voltage U detected by the voltage detecting means 340 with the first voltage predetermined value U1.

When it is determined in step S310 that the input voltage U is not less than the first voltage predetermined value U1, it proceeds to step S342 to maintain the current driving mode in the half-step driving mode. When it is determined in step S310 that the input voltage U is less than the first voltage predetermined value U1, the ambient temperature T detected by the temperature detecting means 360 is then compared with the first temperature predetermined value T1 in step S330.

When it is determined in step S330 that the ambient temperature T is less than the first predetermined temperature T1, the current driving mode (half-step driving mode) is switched to the full-step driving mode in step S331 because it cannot satisfy the requirement of the half-step driving. When the ambient temperature T is not less than the first predetermined temperature T1, the current driving mode is maintained in the half-step driving mode, see step S342.

If it is determined in step S02 that the current driving mode is the full-step driving mode, proceeding to step S320, the input voltage U detected by the voltage detecting means 340 is compared with a second voltage predetermined value U2, wherein the second voltage predetermined value U2 is greater than the first voltage predetermined value U1.

When it is determined in step S320 that the input voltage U is greater than the second voltage predetermined value U2, the current driving mode (full-step driving mode) is switched to the half-step driving mode in step S341 because it can fully satisfy the requirement of the half-step driving. When it is determined in step S320 that the input voltage U is not higher than the second voltage predetermined value U2, it is then determined in step S340 that the ambient temperature T detected by the temperature detecting means 360 is compared with a second temperature predetermined value T2, wherein the second temperature predetermined value T2 is greater than the first temperature predetermined value T1.

If it is determined in step S340 that the ambient temperature T is higher than the second temperature predetermined value T2, the current driving mode (full-step driving mode) is switched to the half-step driving mode in step S341. If it is determined in step S340 that the ambient temperature T is not higher than the second temperature predetermined value T2, the current driving mode is maintained in the full-step driving mode, see step S332.

The driving manner in steps S332 and S342 may continue until the driving of the electronic expansion valve is finished (see step S10).

The control system and control method of the third embodiment combine the input voltage of the first embodiment with the ambient temperature of the second embodiment, thereby more accurately judging and controlling the driving condition of the stepping motor.

< fourth embodiment >

Fig. 8 is a schematic functional block diagram of a control system for an electronic expansion valve according to a fourth embodiment of the present disclosure. As shown in fig. 8, the control system according to the fourth embodiment includes: a switching power supply 420 for supplying a dc power to the stepping motor 410 of the electronic expansion valve; a Negative Temperature Coefficient (NTC) resistor 450 for suppressing surge current from being applied to the input terminal of the switching power supply 420; and a control means 430 for controlling the driving of the stepping motor 410 in the full-step driving mode and switching to the half-step driving mode according to a set time when the electronic expansion valve is started.

In the control system of the fourth embodiment, the control means 430 drives the stepping motor in the full-step driving mode (i.e., the safety driving mode) first at the time of starting the electronic expansion valve, and then makes the full-step driving continue for a predetermined period of time (i.e., the set time). The set time may be set according to the condition of the stepping motor. For example, when the stepping motor is driven in the full-step driving mode for a set time, the operation of the electronic device reaches a steady state, and heat generated by the electronic device is transferred to the surrounding environment and causes the ambient temperature to rise, so that the resistance value of the negative temperature coefficient resistor does not increase or increases little (i.e., the input voltage of the input terminal of the switching power supply is not significantly reduced).

To this end, the control device 430 may include a timer 432 for timing the operation time of the full step driving.

Fig. 9 is a flowchart illustrating a control method of the control system of fig. 8. A control method of the control system of fig. 8 is described below with reference to fig. 9.

Steps S00, S01, S02, and S10 in fig. 9 are the same as those in fig. 3, and are not described in detail here. The following mainly describes the steps in fig. 9 different from fig. 3.

It is determined at step S02 whether the current driving mode is the full-step driving mode. If it is determined in step S02 that the current drive mode is not the full-step drive mode (i.e., the half-step drive mode), it proceeds to step S410 to switch the current drive mode (i.e., the half-step drive mode) to the full-step drive mode.

Then, the operation time of the full-step driving mode is counted by the timer 432 (hereinafter, referred to as a measurement time for convenience of description). It is determined in step S411 whether the measured time reaches the set time. If it is determined that the measured time does not reach the set time, the full-step driving mode is maintained in step S412. If it is determined that the measured time reaches the set time, the half-step driving mode is switched to in step S421.

If it is determined in step S02 that the current drive mode is the full-step drive mode, it proceeds to step S420 to determine whether the measured time reaches the set time. If it is determined that the measured time does not reach the set time, the full-step driving mode is maintained in step S412. If it is determined that the measured time reaches the set time, the half-step driving mode is switched to in step S421.

The driving manner in steps S412 and S421 may continue until the driving of the electronic expansion valve is finished (see step S10).

According to the control system, only a detection circuit comprising a plurality of resistors and detection devices needs to be added, so that the added cost is lower, and the development period can be reduced.

It should be understood that the above-described respective control methods of the present disclosure are not limited to the illustrated specific examples. For example, the comparing step or the determining step may be repeatedly performed after a predetermined time interval to switch to the half-step driving in the case where the high driving condition is satisfied and to switch to the full-step driving in the low driving condition.

Further, alternatively or additionally, some less important high current devices may be shut down when the electronic expansion valve is activated, thereby ensuring the current supplied to the stepper motor.

Although various embodiments of the present disclosure have been described in detail herein, it is to be understood that the disclosure is not limited to the particular embodiments described and illustrated in detail herein, and that other variations and modifications may be effected by one skilled in the art without departing from the true spirit and scope of the disclosure. All such variations and modifications are intended to fall within the scope of the present disclosure.

Claims

1. A control system for an electronic expansion valve, wherein the electronic expansion valve comprises a valve member comprising a valve body and a valve spool movable relative to the valve body, and a motor configured to move the valve spool to open or close the electronic expansion valve,

the control system includes:

a power supply device configured to supply power to the motor; and

a control device including a first mode and a second mode for the motor driving mode, wherein a current required to drive the motor in the first mode is less than a current required to drive the motor in the second mode, and the control device is configured to selectively drive the motor in the first mode or the second mode according to a preset motor driving related parameter when the electronic expansion valve is activated.

2. The control system according to claim 1, wherein the preset motor drive related parameter includes an input voltage of the power supply device, the control system further comprising a voltage detection device configured to detect the input voltage of the power supply device,

wherein the control device drives the motor in the first mode or the second mode according to the input voltage.

3. The control system of claim 2, wherein the control device is configured to:

when the detected input voltage is lower than a first voltage predetermined value, the control device drives the motor in the first mode;

when the detected input voltage is higher than a second voltage predetermined value, the control device drives the motor in the second mode, the second voltage predetermined value being greater than the first voltage predetermined value; and

when the detected input voltage is equal to or higher than the first voltage predetermined value but equal to or lower than the second voltage predetermined value, the control device drives the motor in the current mode.

4. The control system of claim 1, wherein the control system further comprises:

a negative temperature coefficient resistance provided at an input side of the power supply device.

5. The control system of claim 4, wherein the preset motor drive related parameter comprises an ambient temperature of the negative temperature coefficient resistance,

the control system further comprises:

a temperature detection device configured to detect an ambient temperature of the negative temperature coefficient resistance.

6. The control system of claim 5, wherein the control device is configured to:

when the detected ambient temperature is lower than a first temperature preset value, the control device drives the motor in the first mode;

when the detected ambient temperature is higher than a second predetermined temperature value, the control device drives the motor in the second mode, wherein the second predetermined temperature value is larger than the first predetermined temperature value; and

when the detected ambient temperature is equal to or higher than the first predetermined temperature value but equal to or lower than the second predetermined temperature value, the control device drives the motor in the current mode.

7. The control system of claim 4, wherein the preset motor drive related parameters include an input voltage of the power supply device and an ambient temperature of the negative temperature coefficient resistance,

the control system further comprises:

a voltage detection device configured to detect an input voltage of the power supply device; and

8. The control system of claim 7, wherein the control device is configured to:

the control means drives the motor in the first mode when the detected input voltage is lower than a first voltage predetermined value and the detected ambient temperature is lower than a first temperature predetermined value;

the control means drives the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value and the detected ambient temperature is higher than a second temperature predetermined value, which are greater than the first voltage predetermined value and greater than the first temperature predetermined value; and

the control means drives the motor in a present mode when the detected input voltage is equal to or higher than the first voltage predetermined value but equal to or lower than the second voltage predetermined value and the detected ambient temperature is equal to or higher than the first temperature predetermined value but equal to or lower than the second temperature predetermined value.

9. The control system of claim 4,

the control system further includes a timer for measuring a driving time of the first mode,

wherein the control system is configured to select to drive the motor in the first mode upon activation of the electronic expansion valve, the preset motor drive related parameter comprises a drive time for the motor drive in the first mode, and

and switching to the second mode when the driving time reaches a set time.

10. The control system according to any one of claims 1 to 9, wherein the motor is a stepping motor, the power supply device is a switching power supply, the first mode is a full-step drive mode, and the second mode is a half-step drive mode.

11. A control method for an electronic expansion valve, wherein the electronic expansion valve comprises a valve member including a valve body and a valve spool movable relative to the valve body, and a motor configured to move the valve spool to open or close the electronic expansion valve,

the control method comprises the following steps:

acquiring a parameter related to driving of the motor; and

power is supplied to the motor through a power supply device to drive the motor,

wherein the motor is selected to be driven in a first mode or a second mode depending on the parameter, the current required to drive the motor in the first mode being less than the current required to drive the motor in the second mode.

12. The control method according to claim 11, wherein,

acquiring a parameter related to driving of the motor includes detecting an input voltage of the power supply device; and

selecting to drive the motor in the first mode or the second mode according to the detected input voltage.

13. The control method according to claim 12, further comprising:

selecting to drive the motor in the first mode when the detected input voltage is lower than a first voltage by a predetermined value;

selecting to drive the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value, the second voltage predetermined value being greater than the first voltage predetermined value; and

when the detected input voltage is equal to or greater than the first voltage predetermined value but equal to or less than the second voltage predetermined value, the current mode is maintained to drive the motor.

14. The control method according to claim 11, further comprising:

a negative temperature coefficient resistor is provided on an input side of the power supply device.

15. The control method according to claim 14, wherein,

acquiring a parameter related to driving of the motor includes detecting an ambient temperature of the negative temperature coefficient resistance; and

selecting to drive the motor in the first mode or the second mode depending on the detected ambient temperature.

16. The control method according to claim 15, further comprising:

selecting to drive the motor in the first mode when the detected ambient temperature is lower than a first temperature predetermined value;

selecting to drive the motor in the second mode when the detected ambient temperature is higher than a second predetermined temperature value, the second predetermined temperature value being greater than the first predetermined temperature value; and

and when the detected ambient temperature is greater than or equal to the first temperature preset value but less than or equal to the second temperature preset value, maintaining the current mode to drive the motor.

17. The control method according to claim 14, wherein,

acquiring a parameter related to driving of the motor includes detecting an input voltage of the power supply device and detecting an ambient temperature of the negative temperature coefficient resistance; and

selecting to drive the motor in the first mode or the second mode according to the detected input voltage and ambient temperature.

18. The control method according to claim 17, further comprising:

selecting to drive the motor in the first mode when the detected input voltage is lower than a first voltage predetermined value and the detected ambient temperature is lower than a first temperature predetermined value;

selecting to drive the motor in the second mode when the detected input voltage is higher than a second voltage predetermined value or the detected ambient temperature is higher than a second temperature predetermined value, wherein the second voltage predetermined value is greater than the first voltage predetermined value and the second temperature predetermined value is greater than the first temperature predetermined value; and

maintaining a current mode to drive the motor when the detected input voltage is equal to or greater than the first voltage predetermined value but equal to or less than the second voltage predetermined value and the detected ambient temperature is equal to or greater than the first temperature predetermined value but equal to or less than the second temperature predetermined value.

19. The control method according to claim 14, wherein,

selecting to drive the motor in the first mode when the electronic expansion valve is activated;

acquiring a parameter related to driving of the motor includes measuring a driving time of the first mode; and

and switching to the second mode when the driving time reaches a set time.

20. The control method according to any one of claims 11 to 19, further comprising:

when starting to drive the motor, it is first determined whether the current mode is the first mode or the second mode.