Device and method for detecting the angular position of a rotating element

Abstract

The present invention provides a device and method for detecting the angular position of a rotating element. The device for detecting the angular position of a rotating element includes a portion to be detected arranged on the rotating element, a detection element for detecting the portion to be detected, and a processing unit for processing the signal from the detection element. The device is characterized in that the portion to be detected includes at least one pattern arranged along the circumference on the rotating element and composed of two halves that can be detected separately by the detection element, and the ratio of the area or length of the region of the two halves detected by the detection element within each pattern range along the circumferential direction of the rotating element is uniquely determined. According to the present invention, not only can the measurement accuracy be significantly improved, but the device for detecting the angular position of the motor shaft has a simple structure, low cost, and requires a small installation space.

Description

Technical Field

[0001] The present invention relates to detection of the angular position of a rotating element, and in particular to a device and method for detecting the angular position of a rotating element. Background Art

[0002] In electric motors such as permanent magnet synchronous motors, driving the motor requires detecting the angular position of the motor's rotor for field-oriented control. This involves determining the direction of the magnetic field applied to the stator based on the magnetic field direction of the rotor's permanent magnets during rotation. Detecting the angular position of the motor's rotor typically requires position sensors such as resolvers, Hall sensors, giant magnetoresistive sensors, and optical encoders. These position sensors are not only expensive but also require specific space within the motor for their installation. For example, giant magnetoresistive sensors typically require the motor's shaft to be non-hollow so that a magnet can be mounted to the end of the shaft to detect the magnetic field. Furthermore, resolvers often require a rotor diameter larger than the motor's shaft to accommodate their installation. Others have proposed detecting the rotor's angular position by installing an LED light on the rotor. This method also requires a large space for the relevant components and suffers from low accuracy.

[0003] Therefore, there is a need to improve the existing devices and methods for detecting the angular position of a rotating element. Summary of the Invention

[0004] An object of the present invention is to provide a device and a method for detecting the angular position of a rotating element, according to which the cost can be reduced.

[0005] Another object of the present invention is to provide a device and method for detecting the angular position of a rotating element. According to the device and method of the present invention, only a small space is required to install the device for detecting the angular position of a rotating element.

[0006] Another object of the present invention is to provide a device and method for detecting the angular position of a rotating element. According to the device and method of the present invention, the accuracy of detecting the angular position of the rotating element can be significantly improved.

[0007] According to the present invention, there is provided a device for detecting the angular position of a rotating element, comprising:

[0008] A portion to be detected is provided on the rotating element;

[0009] a detection element for detecting the part to be detected; and

[0010] a processing unit for processing the signal from the detection element;

[0011] It is characterized in that the part to be detected includes at least one pattern arranged along the circumferential direction on the rotating element and composed of two halves that can be detected separately by the detection element, and the ratio of the area or length of the area of ​​the two halves detected by the detection element within each pattern range along the circumferential direction of the rotating element is uniquely determined.

[0012] Preferably, the two halves form a rectangular shape when unfolded on a plane, and the two halves are divided along a diagonal line of the rectangle.

[0013] Preferably, the two halves are formed directly on the rotary element.

[0014] Preferably, the two halves are arranged on a cylindrical collar, and the collar is fixedly mounted on the rotating element.

[0015] Preferably, the two halves are a light half and a dark half distinguished by color.

[0016] Preferably, the light half is a white half and the dark half is a black half.

[0017] Preferably, the rotating element is a shaft of an electric motor.

[0018] Preferably, the motor is a permanent magnet synchronous motor, and a pattern consisting of the two halves is provided within every 360° / N in the circumferential direction of the rotating shaft, wherein N is the number of pairs of magnetic poles provided on the stator of the motor.

[0019] Preferably, the detection element is an infrared sensor comprising a transmitter and a receiver.

[0020] Preferably, the device for detecting the angular position of a rotating element further comprises a light shield covering the infrared sensor and having a slit.

[0021] Preferably, the processing unit further includes:

[0022] A power supply circuit receiving electrical energy from the outside and used to power the detection element;

[0023] a signal amplifier for amplifying the photoelectric signal from the detection element; and

[0024] A signal processor processes the signal amplified by the signal amplifier, wherein the processed signal is provided to the microcontroller of the rotating element.

[0025] Preferably, the power supply circuit, the signal amplifier and the signal processor are integrated into a printed circuit board.

[0026] According to another aspect of the present invention, there is provided a method for detecting an angular position of a rotating element, comprising:

[0027] A portion to be detected is provided on the rotating element, wherein the portion to be detected includes at least one pattern arranged along the circumference of the rotating element and consisting of two halves that can be distinguishably detected by a detection element, and a ratio of the areas or lengths of the two halves detected by the detection element within each pattern range along the circumference of the rotating element is uniquely determined;

[0028] Detecting the portion to be detected to obtain a ratio of the areas or lengths of the two halves detected by the detection element; and

[0029] A signal representing the ratio is processed.

[0030] Preferably, the processed signal is provided to a microcontroller of the rotating element.

[0031] According to the present invention, the angular position of the rotating shaft can be uniquely determined by detecting at least one pattern formed of two halves disposed on the rotating shaft using a detection element. This significantly improves measurement accuracy and provides a device for detecting the angular position of a motor shaft that is simple in structure, low in cost, and requires minimal installation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the attached figure:

[0033] Figure 1 is a simplified schematic diagram schematically showing a motor provided with a device for detecting the angular position of a motor shaft according to a preferred embodiment of the present invention;

[0034] Figure 2 It is installed Figure 1 A three-dimensional schematic diagram of a collar on the rotating shaft of the motor;

[0035] Figure 3 yes Figure 2 A plan view of the ring body after the ring is unfolded;

[0036] Figure 4 is a schematic diagram showing detection light projected onto the unfolded collar body; and

[0037] Figure 5The figure schematically shows a processing unit for processing a signal from a detection element of an apparatus for detecting the angular position of a motor shaft according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in detail below with reference to examples. It should be understood by those skilled in the art that these exemplary embodiments are not intended to impose any limitations on the present invention.

[0039] Figure 1 FIG is a simplified diagram schematically showing a motor provided with a device for detecting the angular position of a motor shaft according to a preferred embodiment of the present invention. Figure 1 The housing of the electric motor is partially omitted. Figure 1 The motor 1 is, for example, a permanent magnet synchronous motor, which generally includes a stator 5 disposed in a housing 3 and a rotor 7 located at the center of the stator 5 and rotatable relative to the stator 5. The rotor 7 includes a rotating shaft 9 and a rotor core mounted on the rotating shaft 9.

[0040] In order to drive the motor 1, it is necessary to detect the angular position of the motor's rotor 7 so that the direction of the magnetic field to be applied to the stator can be determined based on the magnetic field direction of the rotor's permanent magnet during rotation. To this end, a device 11 for detecting the angular position of a motor shaft according to a preferred embodiment of the present invention includes a portion to be detected 13 disposed on the shaft 9, a detection element 15 for detecting the portion to be detected, and a processing unit 17 for processing the signal from the detection element. According to a preferred embodiment, the portion to be detected 13 disposed on the shaft 9 is a collar 19 fixed to the shaft 9. Figure 2 It is installed Figure 1 A three-dimensional schematic diagram of the collar on the rotating shaft of the motor, Figure 3 yes Figure 2 A plan view of the ring body after the ring is unfolded. Figure 2 As shown, the collar 19 is a cylindrical sleeve. When the collar 19 is unfolded, the collar body 19a should have Figure 3 The rectangular shape shown. Figure 3 The diagonal line 19b of the rectangular ring body 19a divides the ring body 19a into a light-colored half 21a and a dark-colored half 21b. In a preferred embodiment, the light-colored half 21a is painted white, and the dark-colored half 21b is painted black. However, it should be understood that the light and dark colors are not limited to white and black, as long as the two parts form an area that can be distinguishably detected by the detection element.

[0041] The detection element 15 for detecting the portion to be detected can be any suitable sensor capable of identifying the pattern consisting of the distinct light-colored half 21a and dark-colored half 21b on the collar 19. As an example, the detection element 15 for detecting the portion to be detected is an infrared sensor comprising an infrared transmitter and an infrared receiver. Of course, the detection element 15 for detecting the portion to be detected can also be other suitable sensors besides infrared sensors. The detection element 15 for detecting the portion to be detected can be mounted on a support 23 fixed to the motor housing 3. The distance between the detection element 15 for detecting the portion to be detected and the collar 19 fixed to the motor shaft 9 is selected to achieve optimal detection accuracy. Preferably, the detection element 15 for detecting the portion to be detected is covered by a light shield 25 having a slit therein so that only a narrow infrared beam is projected onto the collar 19. This allows only a small area on the collar 19 to be detected, and adjacent areas do not affect the detection, thereby further improving detection accuracy.

[0042] Figure 4This schematic diagram illustrates the projection of detection light onto an unfolded collar body, used to explain the operating principle of the device for detecting the angular position of a motor shaft according to the present invention. The dashed box 27 in the diagram represents an infrared beam emitted by the transmitter of the detection element 15 detecting the portion to be detected and projected onto the collar 19. This infrared beam is reflected by the pattern formed by the light-colored half 21a and the dark-colored half 21b of the collar 19 and is received by the receiver of the detection element 15 detecting the portion to be detected. Assuming that when the motor rotates, the pattern composed of the light half 21a and the dark half 21b on the ring 19 moves from left to right relative to the infrared light beam represented by the dotted box 27, then at each moment in the process of the motor shaft rotating one circle, that is, 360°, the area of ​​the light half 21a and the dark half 21b detected by the infrared beam have corresponding values, that is, the ratio of the area of ​​the light half 21a detected by the infrared beam to the area of ​​the dark half 21b detected by the infrared beam is uniquely determined. Therefore, after obtaining the ratio of the area of ​​the light half 21a detected by the infrared beam to the area of ​​the dark half 21b detected by the infrared beam, the angular position of the motor shaft at the corresponding moment can be known or tracked. Of course, it should be understood that, instead of determining the angular position of the motor shaft by obtaining the ratio of the area of ​​the light-colored half 21a detected by the infrared beam to the area of ​​the dark-colored half 21b detected by the infrared beam, the angular position of the motor shaft can also be determined by obtaining the ratio of the length of the area of ​​the light-colored half 21a detected by the infrared beam to the length of the area of ​​the dark-colored half 21b detected by the infrared beam. In this application, the "length" of the two detected halves should refer to the length of the detected area of ​​the two halves along a direction parallel to the motor shaft.

[0043] In the preferred embodiment described above, a light-colored half 21a and a dark-colored half 21b are symmetrically arranged along the entire circumference of the collar 19, that is, within a 360° circumferential range. This corresponds to the fact that the motor's stator has only one pair of magnetic poles. If the motor's stator has two pairs of magnetic poles, then a light-colored half 21a and a dark-colored half 21b are symmetrically arranged along half the circumference of the collar 19, that is, within each 180° circumferential range. Similarly, if the motor's stator has N pairs of magnetic poles, then a light-colored half 21a and a dark-colored half 21b are symmetrically arranged along 1 / N of the circumference of the collar 19, that is, within each 360° / N circumferential range. In this way, the pattern consisting of a light-colored half 21a and a corresponding dark-colored half 21b corresponds to a corresponding pair of magnetic poles of the motor's stator.

[0044] Figure 5The figure schematically shows a processing unit for processing the signal from the detection element of the device for detecting the angular position of the motor shaft according to a preferred embodiment of the present invention. Figure 5 As shown, the processing unit 17 for processing the signals from the detection element includes a power supply circuit 25 that receives external electrical energy and is used to power the detection element 15 that detects the portion to be detected. The processing unit 17 also includes a signal amplifier 27 for amplifying the photoelectric signal from the detection element 15 that detects the portion to be detected, and a signal processor 29 for processing the signal amplified by the signal amplifier 27. The signal processor 29 processes the photoelectric signal using control software and converts it into a differential signal that can be received by the motor's microcontroller. The motor's microcontroller controls the current or voltage applied to the motor's stator based on the differential signal representing the angular position of the shaft, thereby controlling the direction of the magnetic field generated by the motor's stator. In a preferred embodiment, the power supply circuit 25, signal amplifier 27, and signal processor 29 of the processing unit 17 for processing the signals from the detection element are integrated onto a single printed circuit board. The processing unit 17 for processing the signals from the detection element can be mounted on the motor housing independently of the detection element 15 that detects the portion to be detected, or it can be integrated into the control panel of the motor's control device.

[0045] In the preferred embodiment above, a pattern consisting of a light half 21a and a dark half 21b is provided on the collar 19, which is then fixed to the motor shaft 9. However, it should be understood that the pattern consisting of the light half 21a and the dark half 21b can be provided directly on the motor shaft 9. In addition, as long as the ratio of the areas of the two distinguishable halves detected by the detection element is uniquely determined in the circumferential direction, the pattern consisting of a light half and a dark half distinguished by color can also be replaced by a pattern consisting of halves that can be detected distinguishably, such as a smooth half and a rough half, or a protruding half and a concave half. Therefore, the pattern in the present invention is not limited to a pattern formed by color. Moreover, the area formed by the two halves after expansion is not limited to a rectangle.

[0046] According to the present invention, by detecting at least one pattern consisting of two halves arranged on the rotating shaft through a detection element, the angular position of the rotating shaft can be uniquely determined, which not only significantly improves the measurement accuracy, but also the device for detecting the angular position of the rotating shaft of the motor has a simple structure, low cost, and requires a small installation space.

[0047] The present invention has been described in detail above with reference to specific preferred embodiments. Obviously, the embodiments described above and shown in the accompanying drawings are exemplary and should not be construed as limiting the present invention. For example, although the preferred embodiment describes the present invention by taking the measurement of the angular position of the rotating shaft of an electric motor as an example, it should be understood that the present invention can be used to measure the angular position of any rotating element. It should be understood by those skilled in the art that various modifications and variations can be made without departing from the spirit of the present invention, and that such modifications and variations do not depart from the scope of protection of the present invention.

Claims

1. A device (11) for detecting the angular position of a rotating element, comprising: A portion to be detected (13) is provided on the rotating element; a detection element (15) for detecting the part to be detected (13); as well as a processing unit (17) for processing the signal from the detection element (15); The invention is characterized in that the portion to be detected (13) includes at least one pattern arranged on the rotating element along the circumferential direction and consisting of two halves that can be detected separately by the detection element, the ratio of the area or length of the region of the two halves detected by the detection element within each pattern range along the circumferential direction of the rotating element is uniquely determined, and the angular position of the rotating element is determined according to the ratio; The two halves form a rectangular shape when unfolded on a plane, and the two halves are separated along a diagonal line of the rectangle.

2. The device (11) for detecting the angular position of a rotating element according to claim 1, characterized in that The two halves are formed directly on the rotary element.

3. The device (11) for detecting the angular position of a rotating element according to claim 1, characterized in that The two halves are arranged on a cylindrical collar (19), and the collar (19) is fixedly mounted on the rotating element.

4. The device (11) for detecting the angular position of a rotating element according to claim 1, characterized in that The two halves are a light half (21a) and a dark half (21b) distinguished by color.

5. The device (11) for detecting the angular position of a rotating element according to claim 4, characterized in that in, The light half (21a) is a white half, and the dark half (21b) is a black half.

6. The device (11) for detecting the angular position of a rotating element according to claim 1, characterized in that The rotating element is the shaft of the electric motor.

7. The device (11) for detecting the angular position of a rotating element according to claim 6, characterized in that The motor is a permanent magnet synchronous motor, and a pattern consisting of the two halves is provided within a range of 360° / N in the circumferential direction of the rotating shaft, wherein N is the number of pairs of magnetic poles provided on the stator of the motor.

8. The device (11) for detecting the angular position of a rotating element according to claim 1, characterized in that The detection element (15) is an infrared sensor comprising a transmitter and a receiver.

9. The device (11) for detecting the angular position of a rotating element according to claim 8, characterized in that The invention also comprises a light shield (25) covering the infrared sensor and having a slit.

10. The device (11) for detecting the angular position of a rotating element according to claim 1, characterized in that The processing unit (17) comprises: a power supply circuit (25) receiving electric energy from the outside and used to supply power to the detection element (15); a signal amplifier (27) for amplifying the photoelectric signal from the detection element (15); and A signal processor (29) processes the signal amplified by the signal amplifier (27), wherein the processed signal is provided to the microcontroller of the rotating element.

11. The device (11) for detecting the angular position of a rotating element according to claim 10, characterized in that The power supply line (25), the signal amplifier (27) and the signal processor (29) are integrated into a printed circuit board.

12. A method for detecting an angular position of a rotating element, comprising: A portion to be detected (13) is provided on the rotating element, wherein the portion to be detected (13) includes at least one pattern arranged along the circumference of the rotating element and consisting of two halves that can be detected separately by the detection element, and a ratio of the area or length of the two halves within each pattern range along the circumferential direction of the rotating element that is detected by the detection element is uniquely determined; Detecting the portion to be detected (13) to obtain the ratio of the area or length of the two halves detected by the detection element; and processing a signal representative of the ratio to determine an angular position of the rotating element based on the ratio; The two halves form a rectangular shape when unfolded on a plane, and the two halves are separated along a diagonal line of the rectangle.

13. The method for detecting the angular position of a rotating element according to claim 12, wherein: The processed signal is provided to the microcontroller of the rotating element.

14. The method for detecting the angular position of a rotating element according to claim 12, wherein: The two halves are formed directly on the rotary element.

15. The method for detecting the angular position of a rotating element according to claim 12, wherein: The two halves are arranged on a cylindrical collar (19), and the collar (19) is fixedly mounted on the rotating element.

16. The method for detecting the angular position of a rotating element according to claim 12, wherein: The two halves are a light half (21a) and a dark half (21b) distinguished by color.

17. The method for detecting the angular position of a rotating element according to claim 12, wherein: The rotating element is the shaft of the electric motor.

18. The method for detecting the angular position of a rotating element according to claim 17, wherein: The motor is a permanent magnet synchronous motor, and a pattern consisting of the two halves is provided within a range of 360° / N in the circumferential direction of the rotating shaft, wherein N is the number of pairs of magnetic poles provided on the stator of the motor.

Images