Motor rotation angle detection system and method

Abstract

The application relates to the technical field of motors, in particular to a motor rotation angle detection system and method, wherein the motor rotation angle detection system comprises a baffle with a spiral-shaped outer edge and a straight edge connecting two ends of the spiral-shaped outer edge; a first reflective light coupling is arranged on the side of the baffle away from the motor; a controller is used for acquiring a first sensing current based on the first reflective light coupling when the motor rotates, and acquiring the rotation angle of the motor according to the first sensing current and a preset conversion relationship; the motor rotation angle detection system drives the baffle to rotate synchronously through the rotation of the motor rotating shaft, so that the covering range of the baffle in the first effective area is changed based on the spiral-shaped outer edge with continuous change characteristics, and then the first reflective light coupling generates the continuously changing first sensing current, so that the controller can calculate the rotation angle of the motor in real time according to the size of the first sensing current, and the motor rotation angle detection system has the advantages of low structural complexity and low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to an electric machine rotation angle detection system and method. BACKGROUND

[0002] Electric machine rotation angle detection is a crucial link in an electric machine control system. Common detection schemes include absolute position photoelectric encoders, Hall sensors, and rotary transformers.

[0003] An absolute position photoelectric encoder accurately maps the rotation angle of an electric machine to binary information on an encoder disk through the cooperation of multiple groups of photoelectric sensors and the encoder disk. The number of code tracks on the encoder disk directly determines the accuracy of angle division, but this also correspondingly increases the number of photoelectric sensors required, thereby increasing the complexity and cost of the system.

[0004] A Hall sensor estimates the rotation angle by detecting the position of a magnet on the shaft of an electric machine. However, this scheme has problems such as poor output linearity and high cost.

[0005] A rotary transformer needs to be used with a decoder to resolve the rotation position of an electric machine. Although its performance is stable, the processing procedure is relatively complex, and the overall cost is high, which limits its widespread application.

[0006] These electric machine rotation angle detection schemes have different degrees of shortcomings in terms of cost, system complexity, linearity, and processing flexibility.

[0007] There is currently no effective technical solution to the above problems. SUMMARY

[0008] The present application aims to provide an electric machine rotation angle detection system and method to detect the rotation angle, making up for the shortcomings in terms of cost, system complexity, linearity, and processing flexibility.

[0009] In a first aspect, the present application provides an electric machine rotation angle detection system for detecting the rotation angle of an electric machine, the system comprising:

[0010] A baffle is fixed on the rotating shaft of the electric machine, and its plate surface is perpendicular to the axis of the rotating shaft. The baffle has a spiral-shaped outer edge and a straight edge connecting the two ends of the spiral-shaped outer edge.

[0011] a first reflective light coupling disposed on a side of the baffle away from the motor, a first effective area having a minimum distance to an axis of the rotating shaft smaller than a minimum distance of a spiral-shaped outer edge to the axis of the rotating shaft, and a maximum distance to the axis of the rotating shaft greater than a maximum distance of the spiral-shaped outer edge to the axis of the rotating shaft, the first effective area being an effective reflective area of the first reflective light coupling on a plane of a plate surface of the baffle away from the motor;

[0012] a controller configured to obtain a first induced current based on the first reflective light coupling when the motor rotates, and obtain a rotation angle of the motor according to the first induced current and a preset conversion relationship.

[0013] The motor rotation angle detection system of the present application can drive the baffle to rotate synchronously by the rotation of the motor rotating shaft, change the coverage range of the baffle in the first effective area based on the spiral-shaped outer edge with continuous variation characteristics, and further make the first reflective light coupling generate a first induced current with continuous variation, so that the controller can calculate the rotation angle of the motor in real time according to the size of the first induced current. The motor rotation angle detection system has the advantages of low structural complexity and low cost, and the spiral-shaped outer edge with continuous variation characteristics can ensure the linear relationship between the first induced current and the rotation angle of the motor, and can output the rotation angle of the motor in real time, accurately and flexibly.

[0014] The motor rotation angle detection system, wherein the straight edge is radially perpendicular to the axis of the rotating shaft.

[0015] In this example, the straight edge is arranged to be radially perpendicular to the axis of the rotating shaft, which can maximize the coverage range of the spiral-shaped outer edge.

[0016] The motor rotation angle detection system, wherein the conversion relationship includes a fitting curve about the first induced current and the rotation angle.

[0017] The motor rotation angle detection system, wherein the first effective area is a rectangular area with a length direction perpendicular to the axis of the rotating shaft.

[0018] The motor rotation angle detection system, wherein the first reflective light coupling includes a first light emitting device and a first light receiving device arranged in an up-down manner, and the light emitting surface of the first light emitting device and the light receiving surface of the first light receiving device are both arranged towards the baffle.

[0019] The motor rotation angle detection system, wherein the baffle has an opening at a middle position between the center and the straight edge.

[0020] The system further comprises:

[0021] a second reflective light coupler arranged on a side of the baffle away from the motor and located at a middle position between the first reflective light coupler and the center of the baffle;

[0022] the process of obtaining a first sensing current based on the first reflective light coupler and obtaining the rotation angle of the motor according to the first sensing current and a preset conversion relationship when the motor rotates includes:

[0023] the process of obtaining a first sensing current based on the first reflective light coupler and obtaining a second sensing current based on the second reflective light coupler when the motor rotates;

[0024] selecting a preset conversion relationship based on the size of the second sensing current;

[0025] obtaining the rotation angle of the motor according to the first sensing current and a preset conversion relationship.

[0026] The motor rotation angle detection system, wherein the minimum distance between the second effective area and the axis center line of the rotating shaft is less than the minimum distance between the opening and the axis center line of the rotating shaft, the maximum distance between the second effective area and the axis center line of the rotating shaft is greater than the maximum distance between the opening and the axis center line of the rotating shaft, and the second effective area is an effective reflective area generated by the second reflective light coupler on the plane where the plate surface of the baffle is located.

[0027] The motor rotation angle detection system, wherein the rotation angle range of the motor in the process of the opening passing through the second effective area covers the rotation angle range of the motor in the process of the straight edge passing through the first effective area.

[0028] The motor rotation angle detection system, wherein the axis center line of the rotating shaft coincides with the spiral axis center of the spiral-shaped outer edge.

[0029] In a second aspect, the application further provides a motor rotation angle detection method applied in a motor rotation angle detection system, and the system includes:

[0030] a baffle fixed on a rotating shaft of a motor and having a plate surface perpendicular to an axis center line of the rotating shaft, the baffle having a spiral-shaped outer edge and a straight edge connecting two ends of the spiral-shaped outer edge;

[0031] A first reflective light coupling is arranged on the side of the baffle away from the motor, the minimum distance between the first effective area and the axis of the rotating shaft is smaller than the minimum distance between the spiral-shaped outer edge and the axis of the rotating shaft, the maximum distance between the first effective area and the axis of the rotating shaft is greater than the maximum distance between the spiral-shaped outer edge and the axis of the rotating shaft, and the first effective area is the effective reflective area generated by the first reflective light coupling on the plane of the plate surface of the baffle away from the motor.

[0032] The method comprises the steps of:

[0033] Obtaining a first induced current based on the first reflective light coupling when the motor rotates;

[0034] Obtaining the rotation angle of the motor according to the first induced current and a preset conversion relationship.

[0035] The motor rotation angle detection method provided by the application can drive the baffle to rotate synchronously through the rotation of the motor rotating shaft, change the coverage range of the baffle in the first effective area based on the spiral-shaped outer edge with continuous variation characteristics, and then make the first reflective light coupling generate a continuously changing first induced current, so as to calculate the rotation angle of the motor in real time according to the size of the first induced current.

[0036] As can be seen from the above, the motor rotation angle detection system and method provided by the application can drive the baffle to rotate synchronously through the rotation of the motor rotating shaft, change the coverage range of the baffle in the first effective area based on the spiral-shaped outer edge with continuous variation characteristics, and then make the first reflective light coupling generate a continuously changing first induced current, so as to calculate the rotation angle of the motor in real time according to the size of the first induced current. The motor rotation angle detection system and method have the advantages of low structural complexity and low cost, and the spiral-shaped outer edge with continuous variation characteristics can ensure the linear relationship between the first induced current and the rotation angle of the motor, and can output the rotation angle of the motor in real time, accurately and flexibly. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The structural schematic diagram of the motor rotation angle detection system provided by the embodiment of the application is shown.

[0038] Figure 2 The working principle schematic diagram of the existing reflective light coupling is shown.

[0039] Figure 3 The position relationship schematic diagram of the baffle and the first reflective light coupling is shown.

[0040] Figure 4 is a partial enlarged view of Figure 3

[0041] Figure 5 ​A schematic view of the position relationship between the baffle and the first reflective light coupler and the second reflective light coupler.

[0042] Figure 6 A graph showing the changes of the first induced current and the second induced current with respect to the rotation angle.

[0043] Figure 7 A flowchart of the motor rotation angle detection method provided by some embodiments of the present application.

[0044] Reference numerals: 1, motor; 2, baffle; 3, first reflective light coupler; 4, controller; 5, first effective area; 6, second reflective light coupler; 21, spiral outer edge; 22, straight edge; 23, opening; 31, first light emitting device; 32, first light receiving device. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0046] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. Meanwhile, in the description of the present application, the terms “first”, “second”, etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0047] In a first aspect, referring to Figure 1 and Figure 3 Some embodiments of the present application provide a motor rotation angle detection system for detecting the rotation angle of a motor 1, which comprises:

[0048] A baffle 2 is fixed on the rotating shaft of the motor 1, and the plate surface of the baffle 2 is perpendicular to the axis of the rotating shaft, the baffle 2 has a spiral outer edge 21 and a straight edge 22 connecting the two ends of the spiral outer edge 21;

[0049] The first reflective light coupling 3 is arranged on the side of the baffle 2 away from the motor 1, the minimum distance between the first effective area 5 and the axis of the rotating shaft is smaller than the minimum distance between the spiral outer edge 21 and the axis of the rotating shaft, the maximum distance between the first effective area 5 and the axis of the rotating shaft is greater than the maximum distance between the spiral outer edge 21 and the axis of the rotating shaft, and the first effective area 5 is an effective reflection area generated by the first reflective light coupling 3 on the plane of the plate surface of the baffle 2 away from the motor 1.

[0050] The controller 4 is configured to acquire a first induced current based on the first reflective light coupling 3 when the motor 1 rotates, and acquire the rotation angle of the motor 1 according to the first induced current and a preset conversion relationship.

[0051] Specifically, as shown in Figure 2 the reflective light coupling generally includes a light receiving device and a light emitting device, and the measurement principle is based on that the light receiving device receives the amount of light reflected by the light emitting device projected on the detected object to generate an induced current to realize object detection, wherein the light receiving device and the light emitting device realize object detection based on an effective reflection area, which is the theoretical maximum intersection of the light-illuminated surface formed by the light emitted by the light emitting device on the surface of the detected object and the projection surface formed by the light-sensitive surface of the light receiving device on the surface of the light-blocking piece (equivalent to the baffle 2), the detected object reflects light by covering part or the entire effective reflection area to make the reflective light coupling generate an induced current based on the light received by the light receiving device, and the area of the effective reflection area covered by the detected object is in a proportional relationship with the induced current.

[0052] More specifically, in the embodiment of the present application, as shown in Figure 1 the rotating shaft of the motor 1 is fixedly connected to the baffle 2 through the rear end, and the first reflective light coupling 3 is arranged on the side of the baffle 2 away from the motor 1 to avoid affecting the rotation output of the front end; in order to accurately describe the conversion relationship between the induced current and the rotation angle of the motor 1, the spiral outer edge 21 appears as a spiral line with a continuously increasing radius on the corresponding plate surface of the baffle 2, that is, the radius increases in a linear manner, which can be described based on r=kθ+c, 0≤θ≤360°, wherein r is the radius of the spiral line, θ is the angle, and k and c are constants.

[0053] It should be noted that the first reflective light coupling 3 can be fixed in a scene or other supporting equipment to maintain a fixed gap distance between it and the baffle 2, and its relative position to the shell of the motor 1 is fixed, so that the corresponding first induced current can be generated based on the reflection of the baffle 2 to detect the rotation angle of the motor 1 when the motor 1 rotates.

[0054] It should be noted that the controller 4 is electrically connected to the first reflective light coupling 3.

[0055] More specifically, as shown in Figure 4As shown, the setting range of the first effective area 5 can cover the minimum radius and the maximum radius of the spiral outer edge 21, so that the baffle 2 is always in the state of partially covering the first effective area 5 when the motor 1 rotates, so that the first induced current generated by the first reflective light coupling 3 continuously changes and the first induced current cyclically changes with respect to the rotation period of each rotation shaft, and the current rotation angle of the motor 1 can be calculated according to the first induced current combined with the preset conversion relationship between the first induced current and the rotation angle of the motor 1.

[0056] The motor rotation angle detection system of the embodiment of the present application drives the baffle 2 to rotate synchronously by the rotation of the rotation shaft of the motor 1, changes the covering range of the baffle 2 in the first effective area 5 based on the spiral outer edge 21 with continuous change characteristics, and then makes the first reflective light coupling 3 generate a first induced current with continuous change, so that the controller 4 can calculate the rotation angle of the motor 1 in real time according to the size of the first induced current. It has the advantages of low structural complexity and low cost, and the spiral outer edge 21 with continuous change characteristics can ensure the linear relationship between the first induced current and the rotation angle of the motor 1, and can output the rotation angle of the motor 1 in real time, accurately and flexibly.

[0057] In some preferred embodiments, the straight edge 22 is radially perpendicular to the axis of the rotation shaft.

[0058] Specifically, the straight edge 22 is arranged to be radially perpendicular to the axis of the rotation shaft, which can maximize the covering range of the spiral outer edge 21. In Figure 3 When the baffle 2 in the motor 1 rotates counterclockwise, the relationship between the rotation angle of the motor 1 and the change of the first induced current is as shown in Figure 6 As shown, the decreasing line part represents the change process of the first induced current when the straight edge 22 passes through the first effective area 5, and the straight edge 22 arranged to be radially perpendicular to the axis of the rotation shaft can reduce the range of the rotation angle of the motor 1 occupied by the change process, and prolong the range of the rotation angle of the motor 1 occupied by the increasing line.

[0059] In some preferred embodiments, the length of the straight edge 22 is 0.9-0.95 times the length of the first effective area 5.

[0060] Specifically, the length of the straight edge 22 is related to the rate of increase of the radius of the spiral outer edge 21 (i.e., the aforementioned constant k). The larger the rate of increase of the radius, the longer the straight edge 22. Based on the relationship that "the minimum distance between the first effective region 5 and the axis of rotation is less than the minimum distance between the spiral outer edge 21 and the axis of rotation, and the maximum distance between the first effective region 5 and the axis of rotation is greater than the maximum distance between the spiral outer edge 21 and the axis of rotation," it can be known that the length of the straight edge 22 must be less than the length of the first effective region 5. The larger the straight edge 22 is, the more conducive it is to generating a first induced current with a greater degree of variation, i.e., increasing the length of the first effective region 5. Figure 6 The slope of the increasing line in the first effective area 5 is used to make fuller use of the first reflective optocoupler 3 to generate a larger difference in the first induced current during the rotation of the motor 1, so that the controller 4 can more accurately analyze and calculate the rotation angle of the motor 1.

[0061] In some preferred embodiments, the conversion relationship includes a fitted curve of the first induced current versus the rotation angle.

[0062] Specifically, to improve the output accuracy of the rotation angle of motor 1, the motor rotation angle detection system of this application determines the conversion relationship by calculating and obtaining a fitted curve. That is, the conversion relationship is obtained by fitting the first induced current corresponding to multiple different rotation angles through multiple measurements. Figure 6 As shown, the fitted curve includes two alternating fitted straight lines. The decreasing line corresponds to the relationship between the first induced current generated during the process of the edge 22 entering the first effective region 5 and leaving the first effective region 5 and the rotation angle of the motor 1. The motor rotation angle detection system of this application obtains the conversion relationship between the first induced current and the rotation angle in one rotation cycle (2π) through experimental measurement and curve fitting. This ensures that the controller 4 can accurately and conveniently calculate the corresponding rotation angle of the motor 1 based on the first induced current, and can also accurately distinguish the two segments of the change characteristics of the first induced current.

[0063] More specifically, in other embodiments, in order to further improve the accuracy of the fitted curve, the transformation relationship can be fitted by dividing it into multiple fitted straight lines based on a preset angular spacing. For example, the rotation period (2π) can be divided into n (n greater than 2) intervals, each interval can be sampled multiple times and fitted with straight lines to obtain fitted straight line segments, and finally these fitted straight line segments can be combined into a fitted curve.

[0064] In some implementations, the conversion relationship includes:

[0065] (1)

[0066] Where I1 is the first induced current, I 10is the first induced current when θ is 0, k and c are constants of the spiral line of the spiral outer edge 21, a is the width of the first effective area 5, and θ is the rotation angle of the motor 1, wherein, θ is defined as Figure 3 The state shown corresponds to θ being 0, and λ is a conversion constant.

[0067] More specifically, the conversion constant λ is a design parameter of the first reflective light coupling 3, which satisfies the relationship I1=λS, and can be obtained according to measurement or viewing of the design specification, wherein S is the effective reflection area, i.e., the area of the intersection of the area of the first effective area 5 and the blocked emitted light of the detection object.

[0068] More specifically, the motor rotation angle detection system of the embodiments of the present application can obtain the fitting curve through a sampling fitting method, or can obtain the corresponding curve relationship by determining the specific form of formula (1) by obtaining the unknown quantity of formula (1) except I1 and θ, or can obtain the final conversion relationship by combining the two methods for data verification, wherein the sampling fitting method is actually equivalent to the process of calculating and determining λ by sampling I1 at multiple angles.

[0069] In some preferred embodiments, the first effective area 5 is a rectangular area with the length direction perpendicular to the axis of the shaft.

[0070] Specifically, by setting the first effective area 5 as a rectangular area with the length direction perpendicular to the axis of the shaft, the motor rotation angle detection system of the embodiments of the present application can more fully utilize the first effective area 5 to make the first reflective light coupling 3 generate a larger difference in the first induced current during the rotation of the motor 1, while also ensuring that the aforementioned conversion relationship contains two clear fitting straight lines in one rotation period.

[0071] In some preferred embodiments, the first reflective light coupling 3 includes the first light emitting device 31 and the first light sensing device 32 arranged above and below, and the light emitting surface of the first light emitting device 31 and the light sensing surface of the first light sensing device 32 are both arranged towards the vane 2.

[0072] Specifically, in the embodiments of the present application, the light emitting surface of the first light emitting device 31 and the light sensing surface of the first light sensing device 32 are both parallel to the outer plate surface of the vane 2, and by changing the distance between the first light emitting device 31 and the first light sensing device 32 and changing the distance between the first light emitting device 31 and the first light sensing device 32 and the vane 2, the size of the first effective area 5 can be adjusted, so that the motor rotation angle detection system of the embodiments of the present application can conveniently adjust the size of the first effective area 5 according to the use requirements, so that the first effective area 5 meets the detection requirements of the rotation angle of the motor 1.

[0073] In some preferred embodiments, as shown in Figure 5As shown, the baffle 2 has an opening 23 at a middle position between the center and the straight edge 22;

[0074] The system further comprises:

[0075] A second reflective light coupler 6 is arranged on the side of the baffle 2 away from the motor 1 at a middle position between the first reflective light coupler 3 and the center of the baffle 2;

[0076] The process of obtaining the first sensing current based on the first reflective light coupler 3 when the motor 1 rotates and obtaining the rotation angle of the motor 1 according to the first sensing current and the preset conversion relationship comprises:

[0077] The first sensing current is obtained based on the first reflective light coupler 3 and the second sensing current is obtained based on the second reflective light coupler 6 when the motor 1 rotates;

[0078] The preset conversion relationship is selected based on the size of the second sensing current;

[0079] The rotation angle of the motor 1 is obtained according to the first sensing current and the preset conversion relationship.

[0080] Specifically, based on the foregoing, it can be known that the conversion relationship comprises two parts of an increasing line and a decreasing line, that is, in the conversion relationship, the value of each first sensing current actually corresponds to two rotation angles, in actual processing, the controller 4 can determine which one of the two rotation angles the first sensing current actually corresponds to according to the change trend or periodic timing of the first sensing current, but in order to further simplify the complexity of the algorithm, the motor rotation angle detection system of the embodiment of the application further introduces the second reflective light coupler 6 to distinguish the increasing line and the decreasing line.

[0081] More specifically, in the embodiment introducing the second reflective light coupler 6, the change relationship of the second sensing current generated by the second reflective light coupler 6 and the first sensing current generated by the first reflective light coupler 3 about the rotation period is as follows: Figure 6As shown, when the opening 23 does not pass through the second active area, the baffle 2 completely covers the second active area, so that the second induced current generated by the second reflective phototransistor 6 always remains at the maximum value; and when the first induced current is located on the decreasing line portion, the opening 23 just passes through the second active area, so that the second induced current generated by the second reflective phototransistor 6 is lower than the maximum value, thereby the controller 4 can determine whether the current first induced current is located on the decreasing line portion by judging whether the second induced current is lower than the maximum value (or comparing the size based on a certain preset threshold value), and then calling the appropriate fitting straight line segment in the conversion relationship to calculate the rotation angle of the motor 1; the motor rotation angle detection system of the embodiment of the application introduces the second reflective phototransistor 6 to determine the second induced current detected thereby as the matching reference of the first induced current and the conversion relationship, so as to improve the accuracy of the rotation angle of the motor 1 on the premise of reducing the algorithm complexity.

[0082] More specifically, the operating principle and composition of the second reflective phototransistor 6 are consistent with those of the first reflective phototransistor 3, and the structure and arrangement mode thereof will not be described herein.

[0083] In some preferred embodiments, the process of selecting the preset conversion relationship based on the size of the second induced current comprises:

[0084] comparing the size relationship between the second induced current and the current threshold value to select the preset conversion relationship, wherein the current threshold value is the second induced current corresponding to the maximum value or the minimum value of the first induced current.

[0085] Specifically, the process of selecting the preset conversion relationship based on the size of the second induced current comprises: Figure 6 It can be seen that when the second induced current is lower than the maximum value, the front part and the rear part of the second induced current still have the problem that a first induced current value corresponds to two rotation angles, therefore, the motor rotation angle detection system of the embodiment of the application further divides the fitting straight line used in the conversion relationship by setting a current threshold value, and in actual operation, the value of the second induced current at the moment when the first induced current reaches the maximum value or the minimum value can be measured as the current threshold value, so that when the second induced current is greater than or equal to the current threshold value, the controller 4 selects the fitting straight line corresponding to the increasing line in the conversion relationship to calculate and obtain the rotation angle of the motor 1, and when the second induced current is less than the current threshold value, the controller 4 selects the fitting straight line corresponding to the decreasing line in the conversion relationship to calculate and obtain the rotation angle of the motor 1.

[0086] In some preferred embodiments, the minimum distance between the second active area and the axis center line of the rotating shaft is less than the minimum distance between the opening 23 and the axis center line of the rotating shaft, the maximum distance between the second active area and the axis center line of the rotating shaft is greater than the maximum distance between the opening 23 and the axis center line of the rotating shaft, and the second active area is an effective reflective area generated by the second reflective phototransistor 6 on the plane where the plate surface of the baffle 2 faces away from the motor 1.

[0087] More specifically, the above arrangement ensures that the second induced current decreases linearly and increases linearly when the opening 23 passes through the second effective area, and ensures that the controller 4 can accurately capture the change of the second induced current and select a suitable conversion relationship to calculate the rotation angle of the motor 1.

[0088] In some preferred embodiments, the rotation angle range of the motor 1 during the process in which the opening 23 passes through the second effective area covers the rotation angle range of the motor 1 during the process in which the straight edge 22 passes through the first effective area 5.

[0089] Specifically, the above arrangement ensures that the range of the rotation angle of the motor 1 corresponding to the process in which the second induced current generated by the second reflective light coupling 6 is below the maximum value includes the range of the rotation angle of the motor 1 corresponding to the process in which the first induced current is on the decreasing line.

[0090] In some preferred embodiments, the axis of the rotating shaft coincides with the helical axis of the helical outer edge 21, which ensures that the first induced current and the rotation angle of the motor 1 have multiple linear relationships in a rotation period.

[0091] In the second aspect, referring to Figure 7 Some embodiments of the present application also provide a motor rotation angle detection method applied in a motor rotation angle detection system, which comprises:

[0092] The baffle 2 is fixed on the rotating shaft of the motor 1, and the plate surface thereof is perpendicular to the axis of the rotating shaft. The baffle 2 has a helical outer edge 21 and a straight edge 22 connecting the two ends of the helical outer edge 21.

[0093] The first reflective light coupling 3 is arranged on the side of the baffle 2 away from the motor 1. The minimum distance between the first effective area 5 and the axis of the rotating shaft is smaller than the minimum distance between the helical outer edge 21 and the axis of the rotating shaft. The maximum distance between the first effective area 5 and the axis of the rotating shaft is greater than the maximum distance between the helical outer edge 21 and the axis of the rotating shaft. The first effective area 5 is the effective reflection area of the first reflective light coupling 3 on the plane of the plate surface of the baffle 2 away from the motor 1.

[0094] The method comprises the following steps:

[0095] S1, acquiring a first induced current based on the first reflective light coupling 3 when the motor 1 rotates;

[0096] S2, acquiring the rotation angle of the motor 1 according to the first induced current and a preset conversion relationship.

[0097] The motor rotation angle detection method of the embodiment of the application drives the baffle 2 to rotate synchronously by the rotation of the motor 1 rotating shaft, changes the coverage range of the baffle 2 in the first effective area 5 based on the spiral-shaped outer edge 21 with continuous change characteristics, and further makes the first reflective light coupling 3 generate a continuously changing first induced current, so as to calculate the rotation angle of the motor 1 in real time according to the size of the first induced current. The motor rotation angle detection method has the advantages of low structural complexity and low cost, and the spiral-shaped outer edge 21 with continuous change characteristics can ensure the linear relationship between the first induced current and the rotation angle of the motor 1, and can output the rotation angle of the motor 1 in real time, accurately and flexibly.

[0098] In addition, the units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0099] Furthermore, the functional modules in each embodiment of the application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0100] In this paper, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0101] The above is only an embodiment of the application and does not limit the protection scope of the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A motor rotation angle detection system for detecting the rotation angle of a motor, characterized in that, The system comprises: a baffle fixed on a rotating shaft of a motor, and a plate surface of the baffle is perpendicular to an axial line of the rotating shaft, the baffle has a spiral outer edge and a straight edge connecting two ends of the spiral outer edge; a first reflective light coupler arranged on a side of the baffle away from the motor, a first effective area has a minimum distance to the axial line of the rotating shaft smaller than a minimum distance of the spiral outer edge to the axial line of the rotating shaft, and a maximum distance of the first effective area to the axial line of the rotating shaft is greater than a maximum distance of the spiral outer edge to the axial line of the rotating shaft, the first effective area is an effective reflective area of the first reflective light coupler on a plane where the plate surface of the baffle is located away from the motor; a controller configured to acquire a first sensing current based on the first reflective light coupler when the motor rotates, and acquire a rotation angle of the motor according to the first sensing current and a preset conversion relationship; the baffle has an opening at a middle position between the center of the baffle and the straight edge; the system further comprises: a second reflective light coupler arranged on the side of the baffle away from the motor at a middle position between the first reflective light coupler and the center of the baffle; the process of acquiring the first sensing current based on the first reflective light coupler and acquiring the rotation angle of the motor according to the first sensing current and the preset conversion relationship when the motor rotates comprises: acquiring the first sensing current based on the first reflective light coupler and acquiring a second sensing current based on the second reflective light coupler when the motor rotates; selecting the preset conversion relationship based on a size of the second sensing current; acquiring the rotation angle of the motor according to the first sensing current and the preset conversion relationship; a second effective area has a minimum distance to the axial line of the rotating shaft smaller than a minimum distance of the opening to the axial line of the rotating shaft, and a maximum distance of the second effective area to the axial line of the rotating shaft is greater than a maximum distance of the opening to the axial line of the rotating shaft, the second effective area is an effective reflective area of the second reflective light coupler on the plane where the plate surface of the baffle is located away from the motor; a rotation angle range of the motor in a process in which the opening passes through the second effective area covers a rotation angle range of the motor in a process in which the straight edge passes through the first effective area.

2. The motor rotation angle detection system according to claim 1, characterized by the straight edge is radially perpendicular to the axial line of the rotating shaft.

3. The motor rotation angle detection system according to claim 1, characterized by the conversion relationship comprises a fitting curve about the first sensing current and the rotation angle.

4. The motor rotation angle detection system according to claim 1, characterized by the first effective area is a rectangular area with a length direction perpendicular to the axial line of the rotating shaft.

5. The motor rotation angle detection system according to claim 1, characterized by the first reflective light coupler comprises a first light emitting device and a first light sensing device arranged in an up-down manner, and a light emitting surface of the first light emitting device and a light sensing surface of the first light sensing device are both arranged towards the baffle.

6. The motor rotation angle detection system according to claim 1, characterized by the axial line of the rotating shaft coincides with a spiral axial center of the spiral outer edge.

7. A method of detecting a rotation angle of a motor, which is applied to a system for detecting a rotation angle of a motor, characterized by The system comprises: a baffle fixed on a rotating shaft of a motor, and a plate surface of the baffle is perpendicular to an axial line of the rotating shaft, the baffle has a spiral outer edge and a straight edge connecting two ends of the spiral outer edge; The first reflective light coupling is arranged on the side of the baffle away from the motor, the minimum distance between the first effective area and the axis of the rotating shaft is smaller than the minimum distance between the spiral outer edge and the axis of the rotating shaft, the maximum distance between the first effective area and the axis of the rotating shaft is greater than the maximum distance between the spiral outer edge and the axis of the rotating shaft, and the first effective area is an effective reflective area generated by the first reflective light coupling on the plane of the plate surface of the baffle away from the motor; The baffle has an opening in the middle position between the center and the straight edge; The system further comprises: The second reflective light coupling is arranged on the side of the baffle away from the motor and located in the middle position between the first reflective light coupling and the center of the baffle; The process of obtaining the first induced current based on the first reflective light coupling when the motor rotates and obtaining the rotation angle of the motor according to the first induced current and a preset conversion relationship comprises: The first induced current is obtained based on the first reflective light coupling and the second induced current is obtained based on the second reflective light coupling when the motor rotates; The preset conversion relationship is selected based on the size of the second induced current; The rotation angle of the motor is obtained according to the first induced current and the preset conversion relationship; The minimum distance between the second effective area and the axis of the rotating shaft is smaller than the minimum distance between the opening and the axis of the rotating shaft, the maximum distance between the second effective area and the axis of the rotating shaft is greater than the maximum distance between the opening and the axis of the rotating shaft, and the second effective area is an effective reflective area generated by the second reflective light coupling on the plane of the plate surface of the baffle away from the motor; The rotation angle range of the motor in the process of passing through the second effective area by the opening covers the rotation angle range of the motor in the process of passing through the first effective area by the straight edge; The method comprises the steps of: The first induced current is obtained based on the first reflective light coupling when the motor rotates; The rotation angle of the motor is obtained according to the first induced current and a preset conversion relationship.

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