Locked-rotor detection method

Abstract

The locked-rotor detection method provided by the invention comprises the following steps: selecting threshold values and comparing the threshold values and counter electromotive force difference values of the four stages at four stages that the current step number is located between the starting step number and the constant-speed operation step number, at the constant-speed operation step number, at the end collision operation step number and between the end collision operation step number and the ending step number respectively; whether locked-rotor happens to the fluid control device or not is determined based on comparison results of the four stages, and in this way, the locked-rotor detection precision of a sensorless detection method on the fluid control device can be improved.

Description

Technical Field

[0001] This invention relates to fluid control technology, and more specifically to a stall detection method that can detect whether a fluid control device has stalled. Background Technology

[0002] Stall detection methods include sensorless detection methods and sensor-based detection methods. Sensorless detection methods involve: acquiring the stator's back electromotive force (EMF), estimating the rotor's rotational speed based on the back EMF, and determining whether the rotor is stalled relative to the stator based on the rotor's rotational speed. Compared to traditional sensor-based detection methods, this approach detects stall without sensors, reducing the complexity and cost of the device. However, the detection accuracy of sensorless methods is significantly lower than that of sensor-based methods. Improving the stall detection accuracy of sensorless methods for fluid control devices remains a technical challenge. Summary of the Invention

[0003] The purpose of this invention is to provide a stall detection method, which is beneficial to improving the stall detection accuracy of sensorless detection methods for fluid control devices.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] On one hand, embodiments of the present invention provide a stall detection method capable of detecting whether a fluid control device has stalled, including:

[0006] include:

[0007] Acquire the drive signal and the back EMF difference value, wherein the drive signal includes the current step number, the start step number, and the end step number;

[0008] If the current step number is between the starting step number and the constant speed running step number, compare the back electromotive force difference value with the first threshold to obtain the first comparison result;

[0009] If the current step number is within the uniform speed running step number, compare the back electromotive force difference value and the second threshold to obtain a second comparison result;

[0010] If the current step number is within the number of steps taken at the impact point, compare the back electromotive force difference value with the third threshold to obtain a third comparison result, wherein the number of steps taken at the impact point is between the number of steps taken at the constant speed and the number of steps taken at the termination point;

[0011] If the current step number is between the number of steps taken at the impact end and the number of steps terminated, the back electromotive force difference value is compared with the fourth threshold to obtain the fourth comparison result;

[0012] The fluid control device is determined to be stuck based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result.

[0013] In the stall detection method for a fluid control device provided in this embodiment of the invention, the stall detection process is subdivided into four stages: the current step number is between the start step number and the constant speed running step number, the current step number is between the constant speed running step number, the collision end running step number, and the collision end running step number and the termination step number. Threshold selection and comparison of the threshold and back EMF difference values ​​of the four stages are performed in each of the four stages. Based on the comparison results of the four stages, it is determined whether the fluid control device has stalled. This approach is beneficial to improving the stall detection accuracy of the sensorless detection method for the fluid control device. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the internal structure of the fluid control device according to an embodiment of the present invention;

[0015] Figure 2 This is a circuit block diagram of the fluid control device according to an embodiment of the present invention;

[0016] Figure 3 This is a power supply principle block diagram of the driving module according to an embodiment of the present invention;

[0017] Figure 4 This is a graph showing the test results of the number of steps and the back electromotive force difference when the fluid control device of this embodiment of the invention experiences a collision.

[0018] Figure 5 This is a schematic diagram illustrating the detection results provided in the first embodiment of the present invention;

[0019] Figure 6 This is a schematic diagram illustrating the detection results provided in the second embodiment of the present invention;

[0020] 100-Fluid control device; 110-Fluid assembly; 120-Stator assembly; 130-Control assembly; 111-Valve seat assembly; 112-Lead screw assembly; 113-Valve core assembly; 114-Stop assembly; 115-Rotor stop; 116-Magnetic rotor; 121-Stator; 1111-Valve port; 1121-Lead screw; 1122-Nut; 1141-Spring guide rail; 1142-Slip ring; 1141a-Upper stop. 1141b - First helical segment, 1141c - Lower stop, 1142a - Second helical segment, 1142b - Stop lever, 1211 - First stator, 1212 - Second stator, 131 - Signal processing module, 132 - Drive module, 1321 - Control unit, 1322 - Bridge drive unit, 1323 - Detection unit, 1321a - Register, 1322a - A-bridge drive unit, 1322b - B-bridge drive unit. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0022] In related technologies, there are two methods for detecting stall: sensor-based detection and sensorless detection. Sensor-based detection involves using a sensor, typically a Hall effect sensor. This sensor detects changes in the magnetic field of the rotor and generates a signal. The fluid control device can then determine whether the rotor is stalled relative to the stator based on whether the signal is abnormal. This method offers high detection accuracy. However, the sensor is generally required to be installed close to the axial or radial side of the rotor, which increases the complexity and cost of the device.

[0023] Sensorless detection methods do not use sensors. When the magnetic rotor rotates relative to the stator, the stator generates a reverse voltage in the opposite direction to the voltage across its terminals. This is the back electromotive force (EMF). The fluid control device estimates the rotational speed of the magnetic rotor relative to the stator based on this back EMF. The fluid control device can determine whether the magnetic rotor is stalled based on whether the rotational speed of the magnetic rotor is abnormal. This method eliminates the need for sensors, which reduces the complexity and cost of the device to some extent. However, the detection accuracy of sensorless detection methods is lower than that of sensor-based detection methods. How to improve the stall detection accuracy of sensorless detection methods for fluid control devices is a technical problem.

[0024] Furthermore, in applications requiring high detection accuracy, sensorless detection methods are clearly not feasible.

[0025] Furthermore, the fluid control device includes at least one of a valve device and a pump device. The valve device or pump device includes the aforementioned magnetic rotor and stator. The detection of fluid stall has high accuracy requirements. Due to the low accuracy of stall detection, the related sensorless detection methods are prone to mechanical failure, electrical failure, and reduced flow control accuracy of the valve device or pump device. Therefore, the application of the related sensorless detection methods in valve devices or pump devices is not ideal.

[0026] Furthermore, the aforementioned fluid control device can be used as part of a thermal management system, enabling fluid control of the medium within the thermal management system.

[0027] To address the aforementioned technical problems, embodiments of the present invention provide a stall detection method capable of detecting whether a fluid control device 100 has stalled, including:

[0028] Acquire the driving signal and the back EMF difference value, wherein the driving signal includes the current step number, the start step number, and the end step number;

[0029] If the current step number is between the starting step number and the constant speed running step number, compare the back electromotive force difference value with the first threshold to obtain the first comparison result;

[0030] If the current step number is within the uniform speed running step number, compare the back electromotive force difference value and the second threshold to obtain a second comparison result;

[0031] If the current step number is within the number of steps taken at the impact point, compare the back electromotive force difference value with the third threshold to obtain a third comparison result, wherein the number of steps taken at the impact point is between the number of steps taken at the constant speed and the number of steps taken at the termination point;

[0032] If the current step number is between the number of steps taken at the impact end and the number of steps terminated, the back electromotive force difference value is compared with the fourth threshold to obtain the fourth comparison result;

[0033] Based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result, it is determined whether the fluid control device 100 has stalled.

[0034] In this stall detection method, the stall detection process is subdivided into four stages: the current step number is between the starting step number and the constant speed running step number, the current step number is between the constant speed running step number, the collision end running step number, and the collision end running step number and the termination step number. In each of the four stages, a threshold is selected and the threshold and back EMF difference value of the four stages are compared. Based on the comparison results of the four stages, it is determined whether the fluid control device 100 has stalled. This approach helps to improve the stall detection accuracy of the sensorless detection method for the fluid control device.

[0035] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0036] The following is a detailed description of a stall detection method provided by an embodiment of the present invention, including:

[0037] Acquire the driving signal and the back electromotive force difference value. The driving signal includes the current step number, the starting step number, and the ending step number. The starting step number can be less than the ending step number or greater than the ending step number.

[0038] If the current step number is between the starting step number and the constant speed running step number, compare the back electromotive force difference value with the first threshold to obtain the first comparison result;

[0039] If the current step number is within the uniform speed running step number, compare the back EMF difference value and the second threshold to obtain the second comparison result;

[0040] If the current step number is between the constant speed running step number and the termination step number, compare the back electromotive force difference value with the fifth threshold to obtain the fifth comparison result;

[0041] Based on the first comparison result, the second comparison result, and the fifth comparison result, it is determined whether the fluid control device 100 is stalled.

[0042] One possible implementation includes:

[0043] If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is greater than the second threshold, and the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, it is determined that the fluid control device 100 has stalled.

[0044] One possible implementation includes:

[0045] If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is not greater than the second threshold, and the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, then it is determined that the fluid control device 100 does not stall.

[0046] One possible implementation includes:

[0047] If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is not greater than the first threshold, or if the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is not greater than the fifth threshold, it is determined that the fluid control device 100 is in an abnormal operating state.

[0048] One possible implementation includes:

[0049] If the current step number is within the number of steps taken at the impact point, compare the back EMF difference value with the third threshold to obtain the third comparison result, where the number of steps taken at the impact point is between the number of steps taken at constant speed and the number of steps taken at the end.

[0050] If the current step number is between the number of steps taken at the impact point and the number of steps terminated, compare the back EMF difference value with the fourth threshold to obtain the fourth comparison result;

[0051] Based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result, it is determined whether the fluid control device 100 has stalled.

[0052] One possible implementation includes:

[0053] If the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the back EMF difference value when the current step number is between the constant speed running step number and the second threshold, the back EMF difference value when the current step number is between the collision end running step number and the third threshold, and the back EMF difference value when the current step number is between the collision end running step number and the termination step number and the fourth threshold, it is determined that the fluid control device 100 has stalled.

[0054] One possible implementation includes:

[0055] If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is not greater than the second threshold, the third comparison result indicates that the back EMF difference when the current step number is between the impact end running step number is not greater than the third threshold, and the fourth comparison result indicates that the back EMF difference when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, it is determined that the fluid control device 100 has stalled.

[0056] One possible implementation includes:

[0057] If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is not greater than the first threshold, or the fourth comparison result indicates that the back EMF difference when the current step number is between the impact end running step number and the termination step number is not greater than the fourth threshold, or the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is greater than the second threshold, the third comparison result indicates that the back EMF difference when the current step number is between the impact end running step number is not greater than the third threshold, and the fourth comparison result indicates that the back EMF difference when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, then it is determined that the fluid control device 100 is in an abnormal operating state.

[0058] In one possible implementation, the fluid control device 100 includes a fluid assembly 110, a stator assembly 120, and a control assembly 130. The fluid assembly 110 includes a magnetic rotor 116, which is rotatably disposed relative to the stator assembly 120. The stator assembly 120 includes at least two stators 121, which are arranged along the axial direction of the magnetic rotor 116. The at least two stators 121 are communicatively connected to the control assembly 130, which is capable of detecting whether the fluid control device 100 is stalled.

[0059] In one possible implementation, the control component 130 includes a drive module 132 and a signal processing module 131;

[0060] At least two stators 121 are communicatively connected to a drive module 132. The drive module 132 can control at least two stators 121 based on drive signals, and can also acquire the back electromotive force of at least two stators 121 and determine the back electromotive force difference based on the back electromotive force of at least two stators 121.

[0061] The signal processing module 131 can obtain the drive signal and back electromotive force from the drive module 132, and determine whether the fluid control device 100 is stalled based on the drive signal and back electromotive force.

[0062] In one possible implementation, the fluid assembly 110 includes a valve seat assembly 111, a lead screw assembly 112, a valve core assembly 113, a stop assembly 114, and a rotor stop portion 115. The valve seat assembly 111 is fixedly connected to the stator assembly 120, and the magnetic rotor 116 is rotatably connected to the valve seat assembly 111. The lead screw assembly 112 includes a lead rod 1121 and a nut 1122 that are fitted together. The lead rod 1121 and the valve core assembly 113 are fixedly connected or have a limiting connection. The stop assembly 114 and the lead rod 1121 are fixedly connected or have a limiting connection. The nut 1122 and the valve seat assembly 111 are fixedly connected or have a limiting connection. At least a portion of the stop assembly 114 is located radially outside the lead rod 1121, and at least a portion of the rotor stop portion 115 is located radially outside the lead rod 1121. The stop assembly 114 and the rotor stop portion 115 are fitted together.

[0063] For ease of understanding, such as Figures 1 to 2 As shown, the fluid control device 100 will be described in detail first. The device includes: fluid assembly 110, stator assembly 120 and control assembly 130.

[0064] The fluid assembly 110 includes a magnetic rotor 116, which is rotatably disposed relative to the stator assembly 120. The stator assembly 120 includes at least two stators 121, which are arranged along the axial direction of the magnetic rotor 116. The at least two stators 121 are communicatively connected to the control assembly 130. The control assembly 130 can control the rotation of the magnetic rotor 116 relative to the stator assembly 120 through the at least two stators 121. The control assembly 130 can also determine whether the fluid control device 100 is stalled, that is, whether the magnetic rotor 116 is stalled relative to the stator assembly 120, and whether the fluid control device 100 is in an abnormal operating state.

[0065] Furthermore, the control component 130 includes a drive module 132 and a signal processing module 131. At least two stators 121 are communicatively connected to the drive module 132, and the drive module 132 is communicatively connected to the signal processing module 131. The drive module 132 may be a stepper motor driver chip, and the signal processing module 131 may be an MCU. The communication connection method between the drive module 132 and the signal processing module 131 includes, but is not limited to, SPI communication.

[0066] In this embodiment, the control component 130 can change the direction and magnitude of the current on two or more stators 121 based on the drive signal, thereby controlling the rotation of the magnetic rotor 116 relative to the stator assembly 120. For ease of understanding, as follows: Figure 1 and Figure 2As shown, there are two stators 121, namely the first stator 1211 and the second stator 1212. The first stator 1211 is communicatively connected to the drive module 132, and the second stator 1212 assembly 120 is communicatively connected to the drive module 132. The drive module 132 can generate a first current pulse and a second current pulse based on the drive signal, output the first current pulse to the first stator 1211 and the second current pulse to the second stator 1212. Under the excitation of the first current pulse and the second current pulse, the first stator 1211 and the second stator 1212 drive the magnetic rotor 116 to rotate relative to the stator assembly 120. The signal processing module 131 can obtain the drive signal from the drive module 132.

[0067] Specifically, the drive signal includes the current step number, the start step number, and the end step number. It should be noted that the relationship between the step number and the pulse number is fixed. For example, in full-step drive mode, whenever the fluid control device 100 receives a pulse signal, it will rotate approximately one fixed step. One step is equivalent to one step, meaning the step number is equivalent to the pulse number. Therefore, it is obvious to those skilled in the art that the pulse number is equivalent to the step number. The start step number can represent the number of steps required for the magnetic rotor 116 to rotate from zero angle to the angle at the start time. The start time can represent the moment when the magnetic rotor 116 begins to rotate relative to the stator assembly 120 under the drive signal. Zero angle refers to a certain angle of 0 degrees between the magnetic rotor 116 and the stator assembly 120. When the magnetic rotor 116 is at zero angle, the corresponding step number is also 0. When the start step number is 0, the position of the magnetic rotor 116 at the start time roughly coincides with the position of the magnetic rotor 116 at zero angle. Generally, the start step number is set to 0 to facilitate subsequent data processing. The termination step count represents the number of rotations required for the magnetic rotor 116 to reach its final angle from zero. The termination time represents the moment when the magnetic rotor 116 finally stops relative to the stator assembly 120 under the drive signal. Generally, the termination step count is greater than the starting step count. The current step count represents the number of rotations required for the magnetic rotor 116 to reach its final angle from zero. The product of the stride and the step count reflects the angular position of the magnetic rotor 116 relative to the stator assembly 120. Since the stride of the magnetic rotor 116 relative to the stator assembly 120 is fixed, the step count directly reflects the angular position of the magnetic rotor 116 relative to the stator assembly 120.

[0068] Furthermore, the drive module 132 includes a bridge drive unit 1322, a detection unit 1323, and a control unit 1321. There are at least two bridge drive units 1322, and the stators of the at least two bridge drive units 1322 are respectively connected to the at least two bridge drive units 1322. The at least two bridge drive units 1322 are also respectively connected to the detection unit 1323, and the detection unit 1323 is connected to the control unit 1321.

[0069] For ease of understanding, such as Figure 3 As shown, there are two bridge drive units 1322, namely A-bridge drive unit 1322a and B-bridge drive unit 1322b. A-bridge drive unit 1322a is communicatively connected to the first stator 1211, and B-bridge drive unit 1322b is communicatively connected to the second stator 1212. A-bridge drive unit 1322a and B-bridge drive unit 1322b are communicatively connected to control unit 1321. Control unit 1321 can control the magnitude and direction of the current on the first stator 1211 and the second stator 1212 based on the drive signal and through A-bridge drive unit 1322a and B-bridge drive unit 1322b. The A-bridge drive unit 1322a and the B-bridge drive unit 1322b are also communicatively connected to the detection unit 1323. The detection unit 1323 is communicatively connected to the control unit 1321. The detection unit 1323 can detect the back EMF of the A-bridge drive unit 1322a and the B-bridge drive unit 1322b, and calculate the back EMF difference value based on the back EMF of the A-bridge drive unit 1322a and the B-bridge drive unit 1322b. The control unit 1321 can acquire the drive signal and the back EMF difference value. The drive signal and the back EMF difference value are stored in the register 1321a of the control unit 1321. The signal processing module 131 is communicatively connected to the register 1321a of the control unit 1321, and the signal processing module 131 can acquire the drive signal and the back EMF difference value from the register 1321a.

[0070] The fluid control device provided in this embodiment can be a valve device. For ease of understanding, as shown below... Figure 1As shown, the fluid assembly 110 includes a valve seat assembly 111, a lead screw assembly 112, a valve core assembly 113, a stop assembly 114, and a rotor stop part 115. A magnetic rotor 116 is rotatably connected to the valve seat assembly 111, and the valve seat assembly 111 is fixedly connected to the stator assembly 120. The valve seat assembly 111 has a valve port 1111. The valve core assembly 113 extends axially toward the valve port 1111. The lead screw assembly 112 includes a lead rod 1121 and a nut 1122 that are fitted together. The lead rod 1121 and the valve core assembly 113 are in a limiting connection. The nut 1122 and the valve seat assembly 111 are fixedly connected or in a limiting connection. The stop assembly 114 and the lead rod 1121 are fixedly connected or in a limiting connection. The rotor stop part 115 is fixedly connected or in a limiting connection to the magnetic rotor 116. The stop assembly 114 and the rotor stop part 115 are fitted together.

[0071] The stop assembly 114 includes a spring guide rail 1141 and a slip ring 1142. The slip ring 1142 and the rotor stop part 115 are configured to cooperate. The spring guide rail 1141 and the magnetic rotor 116 are fixedly connected or limitedly connected. The spring guide rail 1141 includes a first helical segment 1141b, and the slip ring 1142 includes a second helical segment 1142a. The rotor stop part 115 is located radially outside the first helical segment 1141b and extends axially along the lead screw 1121. The first helical segment 1141b and the second helical segment 1142a are helically engaged, and the second helical segment 1142a can rotate helically relative to the first helical segment 1141b. The top end of the second spiral section 1142a is provided with an upper stop 1141a, which extends radially outward from the lead screw 1121. The upper stop 1141a can prevent the slip ring 1142 from spiraling upward relative to the spring guide rail 1141. When the slip ring 1142 spirals to the upper limit position, the slip ring 1142 can abut against the upper stop 1141a, which can prevent the slip ring 1142 from continuing to move upward. The abutment between the slip ring 1142 and the upper stop 1141a is also referred to as the impact end of the fluid control device 100. The bottom end of the second helical segment 1142a is provided with a lower stop 1141c, which extends radially outward from the lead screw 1121. The lower stop 1141c can prevent the slip ring 1142 from spiraling downward relative to the spring guide rail 1141. When the slip ring 1142 spirals to the lower limit position, the slip ring 1142 can abut against the lower stop 1141c, which can prevent the slip ring 1142 from continuing to move downward. The abutment between the slip ring 1142 and the lower stop 1141c is also referred to as the impact end of the fluid control device 100. The slip ring 1142 includes a stop bar 1142b, which extends radially outward from the second helical segment 1142a and can abut against the rotor stop 115.

[0072] To facilitate understanding, the relationship between the rotation of the magnetic rotor 116 relative to the stator assembly 120 and the back electromotive force (EMF) difference is explained in detail below. When the magnetic rotor 116 rotates relative to the stator assembly 120, the stator generates a back EMF. The back EMF difference can be calculated based on the back EMFs of two or more stators. For ease of understanding, the process of obtaining the back EMF difference includes:

[0073] The drive module 132 acquires the back electromotive force of the first stator 1211 and the back electromotive force of the second stator 1212;

[0074] The drive module 132 calculates the back electromotive force difference based on the back electromotive force of the first stator 1211 and the back electromotive force of the second stator 1212. The back electromotive force difference can be the difference between the back electromotive force of the first stator 1211 and the back electromotive force of the second stator 1212.

[0075] The signal processing module 131 can obtain the back electromotive force difference value from the drive module 132.

[0076] The back EMF difference value is related to the rotational speed of the magnetic rotor 116 relative to the stator assembly 120 as follows: when the magnetic rotor 116 is running at a constant or approximately constant speed relative to the stator assembly 120, the back EMF difference value is small; when the magnetic rotor 116 is accelerating relative to the stator assembly 120, the back EMF difference value is large; when the magnetic rotor 116 is decelerating relative to the stator assembly 120, the back EMF difference value is large; when the magnetic rotor 116 stalls relative to the stator assembly 120, the back EMF difference value is large. Therefore, to a certain extent, the magnitude of the back EMF difference value can be mapped to the stall condition of the magnetic rotor 116 relative to the stator assembly 120.

[0077] Driven by the drive signal, the fluid control device 100 can operate without collision. The change in rotational speed of the magnetic rotor 116 relative to the stator assembly 120 presents the following stages: At startup, the stator assembly 120 drives the magnetic rotor 116 to accelerate, and the rotational speed of the magnetic rotor 116 relative to the stator assembly 120 gradually increases from zero until it reaches the target speed for stable operation. This stage is defined as the startup operation stage, and the number of startup steps can define the starting position of the startup operation stage. Subsequently, the stator assembly 120 drives the magnetic rotor 116 to run at a constant speed, and the rotational speed is maintained at approximately a certain value. The rotational speed of the magnetic rotor 116 relative to the stator assembly 120 is in a state of uniform rotation, and this stage is defined as the uniform speed operation stage, and the number of uniform speed steps can define the uniform speed operation stage. Finally, the stator assembly 120 drives the magnetic rotor 116 to decelerate, and the rotational speed of the magnetic rotor 116 relative to the stator assembly 120 gradually decreases until it stops. This stage is defined as the braking operation stage, and the number of termination steps can define the termination position of the braking operation stage.

[0078] Driven by the drive signal, the fluid control device 100 can generate a collision end. The change in the rotational speed of the magnetic rotor 116 relative to the stator assembly 120 presents the following stages: At startup, the stator assembly 120 drives the magnetic rotor 116 to accelerate, and the rotational speed of the magnetic rotor 116 relative to the stator assembly 120 gradually increases from zero until the speed reaches the target speed for stable operation. This stage is defined as the startup operation stage, and the number of startup steps can define the starting position of the startup operation stage. Subsequently, the stator assembly 120 drives the magnetic rotor 116 to run at a constant speed, and the rotational speed is maintained at approximately a certain value. The rotational speed of the magnetic rotor 116 relative to the stator assembly 120 exhibits a state of uniform rotation. This stage is defined as the uniform speed operation stage, and the number of uniform speed operation steps can be expressed as the range of steps in the uniform speed operation stage. Then, the fluid control device 100 experiences a collision, and the magnetic rotor 116 reciprocates relative to the stator assembly 120. The rotational speed of the magnetic rotor 116 relative to the stator assembly 120 increases and decreases. This stage is defined as the collision end operation stage, and the number of collision end operation steps can be expressed as the range of steps in the collision end operation stage. Finally, the stator assembly 120 drives the magnetic rotor 116 to decelerate. The rotational speed of the magnetic rotor 116 relative to the stator assembly 120 gradually decreases until it stops. This stage is defined as the braking operation stage, and the number of termination steps can define the termination position of the braking operation stage.

[0079] The back electromotive force difference can be mapped to the stall condition of the magnetic rotor 116 relative to the stator assembly 120 at different stages. For ease of understanding, as follows: Figure 4The figure shows the test results of the number of steps and back electromotive force difference when the fluid control device 100 experiences a collision. The horizontal axis represents the number of steps, and the vertical axis represents the back electromotive force difference. S1 represents the start-up operation stage, S2 represents the constant speed operation stage, S3 represents the collision operation stage, and S4 represents the braking operation stage. The number of steps in the start-up stage is approximately 36.3, the number of steps in the start-up operation stage is approximately 36.3 to 36.5, the number of steps in the constant speed operation stage is approximately 36.5 to 39.35, and the number of steps in the constant speed operation stage can be defined as the constant speed operation steps. The number of steps in the collision operation stage is approximately 39.35 to 41.35, the number of steps in the braking operation stage is approximately 41.35 to 43.5, and the number of steps in the termination stage is approximately 43.5. During the startup phase, the waveform of the back EMF difference exhibits a peak-like bulge, with the value rising and falling sharply over time. This reflects the characteristic that the acceleration of the magnetic rotor 116 relative to the stator assembly 120 first increases and then decreases until the magnetic rotor 116 reaches the target speed relative to the stator assembly 120. During the stable operation phase, the waveform of the back EMF difference is essentially a horizontal line, with a value that is essentially zero. This reflects that the acceleration of the magnetic rotor 116 relative to the stator assembly 120 is essentially zero, and the magnetic rotor 116 maintains a relatively constant speed relative to the stator assembly 120. During the collision-end operation phase, the waveform of the back EMF difference exhibits a jagged, jumping pattern, with its value fluctuating between large and small. This reflects that the acceleration of the magnetic rotor 116 relative to the stator assembly 120 also fluctuates between large and small. During the braking operation phase, the waveform of the back electromotive force difference (EMF) difference appears as multiple continuous horizontal lines, with the back EMF difference value generally greater than zero. This reflects that the magnitude of the acceleration of the magnetic rotor 116 relative to the stator assembly 120 first gradually increases and then gradually decreases until the rotational speed of the magnetic rotor 116 relative to the stator assembly 120 is zero. In different phases, the back EMF difference value and the number of steps exhibit different relationship characteristics. In this embodiment, the control component 130 can perform stall detection separately for three phases (start-up operation phase, constant speed operation phase, and braking operation phase) or four phases (start-up operation phase, constant speed operation phase, impact-end operation phase, and braking operation phase). This setting helps improve the accuracy of stall detection.

[0080] For ease of understanding, the first embodiment performs stall detection in three stages respectively. The stall detection method of the fluid control device 100 provided in the first embodiment has the following steps:

[0081] P1: Obtain the drive signal and the back EMF difference value, where the drive signal includes the current step number, the start step number, and the end step number;

[0082] P2: Based on the current step number, select the corresponding threshold and the back EMF difference value for comparison to obtain the comparison result. The corresponding thresholds include the first threshold, the second threshold, and the fifth threshold.

[0083] P3: Based on the comparison results, determine whether the fluid control device 100 is stalled or in an abnormal operating state.

[0084] In P1 above, the signal processing module 131 obtains the driving signal and the electromotive force difference value from the register 1321a of the driving module 132.

[0085] The above P2 specifically includes:

[0086] P21: If the current step number is between the starting step number and the constant speed running step number, compare the back electromotive force difference value with the first threshold to obtain the first comparison result;

[0087] For ease of understanding, the following explains P21 in detail. The number between the starting step number and the constant speed running step number can refer to the number of steps in the startup running phase. The current step number being between the starting step number and the constant speed running step number means that the signal processing module 131 determines that the current step number is in the startup running phase.

[0088] If the signal processing module 131 determines that the current step number is within the startup phase, it compares the back EMF difference value of the startup phase with a first threshold. If the back EMF difference value of the startup phase is greater than the first threshold, the signal processing module 131 marks the startup phase state as T; otherwise, it marks it as F.

[0089] It should be noted that the first threshold can be preset in the signal processing module 131. The number of constant-speed running steps can be preset in the signal processing module 131, or it can be calculated based on the start and end steps, as shown in the following formula:

[0090] M = a * b, N = c * d, where M is the upper limit of the number of steps in constant speed running, a is the final step number, b is a constant, N is the lower limit of the number of steps in constant speed running, c is the starting step number, and d is a constant. b can be 1.1, and d can be 0.9.

[0091] P22: If the current step number is within the uniform speed running step number, compare the back electromotive force difference value and the second threshold to obtain the second comparison result;

[0092] For ease of understanding, the following explanation of page 22 will clarify that the number of steps in a uniform speed operation can refer to the number of steps within a uniform speed operation phase. The current step number being within the uniform speed operation phase refers to the number of steps determined by the signal processing module 131.

[0093] If the signal processing module 131 determines that the current step number is within the uniform speed running phase, it compares the back electromotive force difference value of the uniform speed running phase with the second threshold. If the back electromotive force difference value of the uniform speed running phase is greater than the second threshold, the signal processing module 131 marks the state of the uniform speed running phase as T; otherwise, it marks it as F.

[0094] P23: If the current step number is between the constant speed running step number and the final step number, compare the back electromotive force difference value with the fifth threshold to obtain the fifth comparison result;

[0095] For ease of understanding, the following explanation of page 23 will clarify this point. The number of steps between the constant-speed running step count and the termination step count can refer to the number of steps in the braking running phase. The current step count being between the constant-speed running step count and the termination step count means that the signal processing module 131 determines that the current step count is within the braking running phase.

[0096] If the signal processing module 131 determines that the current step number is within the braking operation phase, it compares the back EMF difference value of the braking operation phase with the fifth threshold. If the back EMF difference value of the braking operation phase is greater than the fifth threshold, the signal processing module 131 marks the state of the braking operation phase as T; otherwise, it marks it as F.

[0097] The above P3 specifically includes:

[0098] P31: If the first comparison result indicates that the back electromotive force difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back electromotive force difference when the current step number is between the constant speed running step number is greater than the second threshold, and the fifth comparison result indicates that the back electromotive force difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, then it is determined that the fluid control device 100 has stalled;

[0099] For ease of understanding, such as Figure 5 As shown below, P31 is explained in detail. P31 indicates that when the state of the start-up operation phase is T, the state of the constant speed operation phase is T, and the state of the braking operation phase is T (that is, mod1), the signal processing module 131 determines that the fluid control device 100 is stalled, that is, the magnetic rotor 116 is stalled relative to the stator assembly 120. However, the position of the valve core assembly 113 relative to the valve seat assembly 111 can reach the expected position.

[0100] P32: If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is not greater than the second threshold, and the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, then it is determined that the fluid control device 100 does not stall.

[0101] For ease of understanding, such as Figure 5As shown below, P32 is explained in detail. P32 indicates that when the state of the start-up operation phase is T, the state of the constant speed operation phase is F, and the state of the braking operation phase is T (that is, mod2), the signal processing module 131 determines that the fluid control device 100 does not stall.

[0102] P33: If the first comparison result indicates that the back electromotive force difference when the current step number is between the starting step number and the constant speed running step number is not greater than the first threshold, or if the fifth comparison result indicates that the back electromotive force difference when the current step number is between the constant speed running step number and the ending step number is not greater than the fifth threshold, it is determined that the fluid control device 100 is in an abnormal operating state.

[0103] For ease of understanding, such as Figure 5 As shown below, P33 is explained in detail. P33 indicates that when the state of the start-up operation phase is F or the state of the braking operation phase is F (that is, any one of mod3 to mod8), the signal processing module 131 determines that the fluid control device 100 is in an abnormal operating state. The abnormal operating state may be that the fluid control device 100 has an electrical fault or a mechanical fault.

[0104] For ease of understanding, the second embodiment performs stall detection in four stages respectively. The stall detection method of the fluid control device 100 provided in the second embodiment has the following steps:

[0105] Pa1: Acquire the driving signal and the back EMF difference value, wherein the driving signal includes the current step number, the start step number, and the end step number;

[0106] Pa2: Based on the current step number, select the corresponding threshold and the back EMF difference value for comparison to obtain the comparison result. The corresponding thresholds include the first threshold, the second threshold, the third threshold, and the fourth threshold.

[0107] Pa3: Based on the comparison results, determine whether the fluid control device 100 is stalled or in an abnormal operating state.

[0108] The differences between the stall detection method in the second embodiment and the stall detection method in the first embodiment include: Pa2 and Pa3.

[0109] The aforementioned Pa2 specifically includes:

[0110] Pa21: If the current step number is between the starting step number and the constant speed running step number, compare the back electromotive force difference with the first threshold to obtain the first comparison result;

[0111] Pa21 and P21 are basically the same, and will not be elaborated on here.

[0112] Pa22: If the current step number is within the uniform speed running step number, compare the back electromotive force difference value and the second threshold to obtain the second comparison result;

[0113] Pa22 and P22 are basically the same, so they will not be elaborated on here.

[0114] Pa23: If the current step number is within the number of steps in the collision course, compare the back EMF difference value with the third threshold to obtain the third comparison result, where the number of steps in the collision course is between the number of steps in the uniform running course and the number of steps to terminate.

[0115] For ease of understanding, Pa23 will be explained in detail below. The number of collision-end running steps can refer to the number of steps in the collision-end running phase. The current step number is the number of steps in the collision-end running phase as determined by the signal processing module 131.

[0116] If the signal processing module 131 determines that the current step number is within the impact-end running phase, it compares the back EMF difference value of the impact-end running phase with the third threshold. If the back EMF difference value of the impact-end running phase is greater than the third threshold, the signal processing module 131 marks the state of the impact-end running phase as T; otherwise, it marks it as F.

[0117] It should be noted that the third threshold can be preset in the signal processing module 131. The number of steps in the impact-end operation phase can also be preset in the signal processing module 131, and the number of steps in the impact-end operation phase can also be obtained by testing the fluid control device 100.

[0118] Pa24: If the current step number is between the number of steps taken at the impact point and the number of steps terminated, compare the back EMF difference with the fourth threshold to obtain the fourth comparison result;

[0119] For ease of understanding, Pa24 is explained in detail below. The number of steps between the impact-end running steps and the termination steps refers to the number of steps in the braking operation phase. The current step number being between the impact-end running steps and the termination steps means that the signal processing module 131 determines that the current step number is within the braking operation phase.

[0120] If the signal processing module 131 determines that the previous step number is within the braking operation phase, it compares the back EMF difference value of the braking operation phase with the fourth threshold. If the back EMF difference value of the braking operation phase is greater than the fourth threshold, the signal processing module 131 marks the state of the braking operation phase as T; otherwise, it marks it as F.

[0121] It should be noted that the fourth threshold can be preset in the signal processing module 131.

[0122] The aforementioned Pa3 specifically includes:

[0123] Pa31: If the back electromotive force difference value when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the back electromotive force difference value when the current step number is between the constant speed running step number and the second threshold, the back electromotive force difference value when the current step number is between the impact end running step number and the third threshold, and the back electromotive force difference value when the current step number is between the impact end running step number and the termination step number and the fourth threshold, it is determined that the fluid control device 100 has stalled;

[0124] For ease of understanding, such as Figure 6 As shown, Pa31 will be explained in detail below. Pa31 means that when the start-up operation phase is T, the constant speed operation phase is T, the collision end operation phase is T, and the braking operation phase is T (that is, mod9), the signal processing module 131 determines that the fluid control device 100 is stalled. However, the position of the valve core assembly 113 relative to the valve seat assembly 111 can reach the expected position.

[0125] Pa32: If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is not greater than the second threshold, the third comparison result indicates that the back EMF difference when the current step number is between the impact end running step number is not greater than the third threshold, and the fourth comparison result indicates that the back EMF difference when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, it is determined that the fluid control device 100 has stalled;

[0126] For ease of understanding, such as Figure 6 As shown below, Pa32 is explained in detail. Pa32 indicates that when the start-up operation phase is T, the constant speed operation phase is F, the collision end operation phase is F, and the braking operation phase is T (i.e., mod10), the signal processing module 131 determines that the fluid control device 100 is stalled and the position of the valve core assembly 113 relative to the valve seat assembly 111 cannot reach the expected position.

[0127] Pa33: If the first comparison result indicates that the back electromotive force difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back electromotive force difference when the current step number is between the constant speed running step number is not greater than the second threshold, the third comparison result indicates that the back electromotive force difference when the current step number is between the impact end running step number is greater than the third threshold, and the fourth comparison result indicates that the back electromotive force difference when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, it is determined that the fluid control device 100 does not stall;

[0128] For ease of understanding, such as Figure 6As shown below, Pa33 is explained in detail. Pa33 means that when the start-up operation stage is T, the constant speed operation stage is F, the collision end operation stage is T, and the braking operation stage is T (that is, mod11), the signal processing module 131 determines that the fluid control device 100 does not stall and the position of the valve core assembly 113 relative to the valve seat assembly 111 can reach the expected position.

[0129] Pa34: If the first comparison result indicates that the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is not greater than the first threshold, or the fourth comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number and the termination step number is not greater than the fourth threshold, or the first comparison result indicates that the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference value when the current step number is between the constant speed running step number is greater than the second threshold, the third comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number is not greater than the third threshold, or the fourth comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, then it is determined that the fluid control device 100 is in an abnormal operating state;

[0130] For ease of understanding, such as Figure 6 As shown below, Pa34 is explained in detail. Pa34 means that when the start-up operation phase is F, the braking operation phase is F, the start-up operation phase is T, the constant speed operation phase is T, the collision end operation phase is F, and the braking operation phase is T (that is, any one of mod10 to mod24), the signal processing module 131 determines that the fluid control device 100 is in an abnormal operation state.

[0131] In summary, the stall detection method provided in this embodiment can detect both fluid control devices 100 that experience a collision and fluid control devices 100 that do not experience a collision. The entire detection process is roughly divided into three or four stages, and each of the three or four stages is tested separately. Based on the detection results of the three or four stages, it is determined whether a stall has occurred. This detection method helps to improve the accuracy of the detection. Moreover, the detection results can also determine whether the valve core assembly 113 of the fluid control device 100 has reached the expected position.

[0132] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A stall detection method, capable of detecting whether a fluid control device (100) has stalled, characterized in that, include: Acquire the drive signal and the back EMF difference value, wherein the drive signal includes the current step number, the start step number, and the end step number; If the current step number is between the starting step number and the constant speed running step number, compare the back electromotive force difference value with the first threshold to obtain a first comparison result, wherein the constant speed running step number is between the starting step number and the ending step number; If the current step number is within the uniform speed running step number, compare the back electromotive force difference value and the second threshold to obtain a second comparison result; If the current step number is within the number of steps in the collision course, compare the back electromotive force difference value with the third threshold to obtain a third comparison result, wherein the number of steps in the collision course is between the number of steps in the uniform speed operation and the number of steps to terminate. If the current step number is between the number of steps taken at the impact end and the number of steps terminated, the back electromotive force difference value is compared with the fourth threshold to obtain the fourth comparison result; Based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result, it is determined whether the fluid control device (100) has stalled.

2. The stall detection method of the fluid control device (100) according to claim 1, characterized in that, include: If the first comparison result indicates that the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference value when the current step number is between the constant speed running step number is greater than the second threshold, the third comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number is greater than the third threshold, and the fourth comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, it is determined that the fluid control device (100) has stalled; If the first comparison result indicates that the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference value when the current step number is between the constant speed running step number is not greater than the second threshold, the third comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number is greater than the third threshold, and the fourth comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, it is determined that the fluid control device (100) does not experience stall.

3. The stall detection method according to claim 2, characterized in that, include: If the first comparison result indicates that the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference value when the current step number is between the constant speed running step number is not greater than the second threshold, the third comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number is not greater than the third threshold, and the fourth comparison result indicates that the back EMF difference value when the current step number is between the impact end running step number and the termination step number is greater than the fourth threshold, it is determined that the fluid control device (100) has stalled.

4. The stall detection method according to any one of claims 1 to 3, characterized in that, include: If the first comparison result indicates that the back EMF difference value when the current step number is between the starting step number and the constant speed running step number is not greater than the first threshold, or if the fourth comparison result indicates that the back EMF difference value when the current step number is between the collision end running step number and the termination step number is not greater than the fourth threshold, it is determined that the fluid control device (100) is in an abnormal operating state.

5. The stall detection method according to any one of claims 1 to 4, characterized in that, include: If the current step number is between the constant speed running step number and the termination step number, and the collision end running step number is not between the start step number and the termination step number, compare the back electromotive force difference value with the fifth threshold to obtain the fifth comparison result; Based on the first comparison result, the second comparison result, and the fifth comparison result, it is determined whether the fluid control device (100) is stalled.

6. The stall detection method according to claim 5, characterized in that, include: If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is greater than the second threshold, and the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, it is determined that the fluid control device (100) has stalled; If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is greater than the first threshold, the second comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number is not greater than the second threshold, and the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, then it is determined that the fluid control device (100) does not stall.

7. The stall detection method according to claim 5 or 6, characterized in that, include: If the first comparison result indicates that the back EMF difference when the current step number is between the starting step number and the constant speed running step number is not greater than the first threshold, or if the fifth comparison result indicates that the back EMF difference when the current step number is between the constant speed running step number and the ending step number is greater than the fifth threshold, it is determined that the fluid control device (100) is in an abnormal operating state.

8. The stall detection method according to any one of claims 1 to 7, characterized in that, include: The fluid control device (100) includes a fluid assembly (110), a stator assembly (120), and a control assembly (130). The fluid assembly (110) includes a magnetic rotor (116) which is rotatably disposed relative to the stator assembly (120). The stator assembly (120) includes at least two stators (121) which are arranged along the axial direction of the magnetic rotor (116). The at least two stators (121) are communicatively connected to the control assembly (130). The control assembly (130) is capable of detecting whether the fluid control device (100) is stalled.

9. The stall detection method according to any one of claims 1 to 8, characterized in that, The control component (130) includes a drive module (132) and a signal processing module (131); At least two of the stators (121) are communicatively connected to the drive module (132). The drive module (132) is able to control at least two of the stators (121) based on the drive signal, and is also able to acquire the back electromotive force of at least two of the stators (121) and determine the back electromotive force difference based on the back electromotive force of at least two of the stators (121). The signal processing module (131) can obtain the driving signal and the back electromotive force from the driving module (132), and detect whether the fluid control device (100) is stalled based on the driving signal and the back electromotive force.

10. The stall detection method according to claim 8 or 9, characterized in that, The fluid assembly (110) includes a valve seat assembly (111), a lead screw assembly (112), a valve core assembly (113), a stop assembly (114), and a rotor stop part (115). The valve seat assembly (111) is fixedly connected to the stator assembly (120), and the magnetic rotor (116) is rotatably connected to the valve seat assembly (111). The lead screw assembly (112) includes a lead screw (1121) and a nut (1122) that are fitted together. The lead screw (1121) and the valve core assembly (113) are connected together. 3) Fixed connection or limiting connection, the stop assembly (114) and the lead screw (1121) are fixedly connected or limiting connection, the nut (1122) and the valve seat assembly (111) are fixedly connected or limiting connection, at least a portion of the stop assembly (114) is located on the radial outside of the lead screw (1121), at least a portion of the rotor stop part (115) is located on the radial outside of the lead screw (1121), and the stop assembly (114) and the rotor stop part (115) are configured to cooperate.

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