Position sensor for motor and motor system

Abstract

The embodiment of the utility model provides a position sensor for a motor and a motor system, the motor comprises a stator and a rotor, the position sensor comprises a transmitting coil, the transmitting coil and the stator are relatively fixedly arranged, and the transmitting coil comprises a plurality of annular and concentrically arranged coils and a resonant capacitor connected with the coils in parallel; the transmission coil and the rotor are relatively and fixedly arranged, the size of the transmission coil is smaller than that of the transmitting coil, and the projection of the transmission coil in a plane perpendicular to the direction of a motor shaft is located in the projection range of the transmitting coil; and the at least two groups of receiving coils are fixedly arranged relative to the stator, and the phase difference between the groups of receiving coils is set at an angle.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and more particularly to a position sensor and motor system for an electric motor. Background Technology

[0002] In electric motors, the rotor's position needs to be obtained in real time to drive the motor. Currently known methods for rotor position detection involve installing rotor position sensors on the motor. Common position sensors include Hall effect sensors, magnetic encoders, photoelectric encoders, and rotary transformers.

[0003] These position sensors are typically mounted on the motor spindle to detect the rotor's position. However, when the motor is in harsh environments, such as high temperature, high pressure, and high vibration, the reliability of the position detection will be greatly affected. Utility Model Content

[0004] This application provides a position sensor and motor system for motors with high detection reliability.

[0005] In a first aspect, this application provides a position sensor for a motor, the motor including a stator and a rotor, the position sensor comprising:

[0006] A transmitting coil is fixedly disposed relative to the stator, and the transmitting coil includes a plurality of ring-shaped and concentrically arranged coils and a resonant capacitor connected in parallel with the coils;

[0007] A transmission coil is fixedly disposed relative to the rotor. The size of the transmission coil is smaller than that of the transmitting coil, and the projection of the transmission coil in a plane perpendicular to the motor axis is located within the projection range of the transmitting coil.

[0008] At least two sets of receiving coils are fixedly arranged relative to the stator, and the phase difference between each set of receiving coils is set by an angle.

[0009] In a second aspect, this application provides a motor system including a motor and a position sensor as described in any embodiment of this application; wherein the transmitting coil and the receiving coil are fixedly disposed relative to the stator, and the transmitting coil is fixedly disposed relative to the rotor.

[0010] In the above embodiments, the position sensor includes a transmitting coil and at least two sets of receiving coils fixed relative to the stator, and a transmitting coil fixed relative to the rotor. The inductance of the transmitting coil itself and the capacitor connected in parallel with it form an LC resonant circuit. After the initial excitation is applied, the LC resonant circuit generates a high-frequency sinusoidal current in the transmitting coil, which in turn generates a high-frequency sinusoidal magnetic field in space. The transmitting coil rotates with the rotor, and the induced voltage generated in the receiving coil by the high-frequency sinusoidal magnetic field generated by the transmitting coil accurately feeds back the rotor's position information. Thus, the position sensor is based on Faraday's law of electromagnetic induction. It achieves the purpose of reflecting the position of one of the coils (i.e., the rotor) through the mutual excitation and conversion of the electric and magnetic fields between the transmitting, transmitting, and receiving coils, as well as the interaction between the magnetic fields. Even in harsh environments such as high temperature, high pressure, and high vibration, the motor can still ensure good position detection accuracy and reliability.

[0011] The motor system provided in the above embodiments belongs to the same concept as the corresponding position sensor embodiments, and thus has the same technical effect as the corresponding position sensor embodiments, which will not be repeated here. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the principle of a position sensor in one embodiment.

[0013] Figure 2 This is a schematic diagram of the transmitting coil in one embodiment.

[0014] Figure 3 This is a schematic diagram of the transmitting coil and the transmitting coil in one embodiment.

[0015] Figure 4 This is a schematic diagram of the transmitting coil and receiving coil in one embodiment.

[0016] Figure 5 This is a schematic diagram of a transmitting coil and a receiving coil in one embodiment.

[0017] Figure 6 This is a schematic diagram of the transmitting coil, transmitting coil, and receiving coil of a position sensor for a linear motor in one embodiment.

[0018] Figure 7 This is a schematic diagram of the transmitting coil, transmitting coil, and receiving coil of a position sensor for a rotary motor in one embodiment.

[0019] Figure 8 This is a schematic diagram of the transmitting coil, transmitting coil, and receiving coil of a position sensor for a rotary motor in another embodiment.

[0020] Figure 9This is a schematic diagram illustrating the conversion principle between the receiving coil of a linear motor and the receiving coil of a rotary motor in one embodiment.

[0021] Figure 10 This is a schematic diagram of the structure of a position sensor in one embodiment.

[0022] Figure 11 for Figure 10 The diagram shows the exploded structure of the position sensor.

[0023] Figure 12 for Figure 10 The diagram shows the arrangement of the transmitting and receiving coils on the stator circuit board of the position sensor.

[0024] Figure 13 This is a wiring diagram of the top wiring layer of the sensor stator circuit board in one embodiment.

[0025] Figure 14 for Figure 13 The diagram shows the wiring diagram of the bottom wiring layer of the sensor stator circuit board.

[0026] Figure 15 for Figure 13 The diagram shows the wiring diagram of the transmitting coil and two sets of receiving coils on the sensor stator circuit board. Detailed Implementation

[0027] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In the following description, the phrase "some embodiments" refers to a subset of all possible embodiments. It should be noted that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0030] It should also be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "inner," "outer," "left," "right," and similar expressions used herein are for illustrative purposes only in conjunction with the embodiments in the accompanying drawings and do not represent the only possible implementations.

[0031] An electric motor is an electromagnetic device that converts or transmits electrical energy based on the law of electromagnetic induction. The main components of an electric motor include a stator and a rotor that moves relative to the stator. It should be noted that common motor types mainly include linear motors and rotary motors. The motion state of the components moving relative to the stator differs in different motor types. In a linear motor, the component moving relative to the stator has linear motion and is generally called the mover. In a rotary motor, the component moving relative to the stator has rotational motion and is generally called the rotor. In this embodiment, for ease of description, the component moving relative to the stator in the motor is collectively referred to as the rotor. Here, "rotor" should be interpreted broadly, including the mover in a linear motor and the rotor in a rotary motor.

[0032] Please see Figure 1 This application provides a position sensor 50 for a motor 40, which includes a stator 41 and a rotor 42. The position sensor 50 includes: a transmitting coil 10, which is fixedly disposed relative to the stator 41 and includes a plurality of ring-shaped and concentrically disposed coils and a resonant capacitor connected in parallel with the coils; a transmitting coil 20, which is fixedly disposed relative to the rotor 42 and has a smaller size than the transmitting coil 10, and the projection of the transmitting coil 20 in a plane perpendicular to the motor axis is located within the projection range of the transmitting coil 10; and at least two sets of receiving coils 30, which are fixedly disposed relative to the stator 41 and have a phase difference of a set angle between each set of receiving coils 30.

[0033] Both the transmitting coil 10 and the receiving coil 30 are fixedly mounted relative to the stator 41 of the motor 40, and the transmission coil 20 is fixedly mounted relative to the rotor 42 of the motor 40. The size of the transmission coil 20 is smaller than that of the transmitting coil 10, and the projection of the transmission coil 20 in the plane perpendicular to the motor axis is within the projection range of the transmitting coil 10. Thus, the high-frequency sinusoidal magnetic field generated by the transmission coil 20 following the rotation of the rotor 42 induces a voltage in the receiving coil 30, which can be output through the receiving coil 30. The position sensor 50 can be connected to an external processing circuit to process the output voltage in the receiving coil 30 and decompose it into a signal that reflects the rotor position.

[0034] In this configuration, with a plane perpendicular to the motor axis as a reference, the projections of the transmitting coil 10 and the receiving coil 30 in the plane are symmetrically arranged. The size of the transmitting coil 20 is smaller than that of the transmitting coil 10, and the projection of the transmitting coil 20 in the plane is asymmetrically arranged. Thus, the induced voltage generated in the receiving coil 30 by the high-frequency sinusoidal magnetic field generated by the transmitting coil 10 is also symmetrical, and they can cancel each other out. This allows the output voltage of the receiving coil 30 to mainly contain the characteristic signal of rotor position detection, simplifying the processing of the output voltage by the external processing circuit and making it easier to determine the rotor position based on the output voltage of the receiving coil 30.

[0035] In the above embodiment, the position sensor 50 includes a transmitting coil 10 fixedly disposed relative to the stator 41, at least two sets of receiving coils 30, and a transmitting coil 20 fixedly disposed relative to the rotor 42. The inductance and resonant capacitance of the transmitting coil 10 are connected in parallel to form an LC resonant circuit. After the initial excitation is applied, the LC resonant circuit generates a high-frequency sinusoidal current in the transmitting coil 10, which in turn generates a high-frequency sinusoidal magnetic field in space. The transmitting coil 20 rotates with the rotor 42, and the induced voltage generated in the receiving coil 30 by the high-frequency sinusoidal magnetic field generated by the transmitting coil 20 is used to accurately feed back the rotor position information. In this way, the position sensor 50 is based on Faraday's law of electromagnetic induction. It achieves the purpose of reflecting the position of one of the coils (i.e., the rotor 42) through the mutual excitation and conversion of the electric field and magnetic field between the transmitting coil 10, the transmitting coil 20, and the receiving coil 30, as well as the interaction between the magnetic fields. Even if the motor 40 is in a harsh environment such as high temperature, high pressure, and high vibration, it can still ensure good position detection accuracy and reliability.

[0036] The position sensor 50 achieves the purpose of feedback on the position of the transmission coil 20 by the mutual excitation and conversion of the electric and magnetic fields between the transmitting coil 10, the transmitting coil 20 and the receiving coil 30, as well as the interaction between the magnetic fields. In this position sensor 50, both the transmitting coil 10 and the receiving coil 30 are mounted on the stator side of the motor 40 and are physically stationary in space, while the transmission coil 20 is mounted on the rotor side of the motor 40 and moves in space with the rotor 42. The rotor position is determined based on the output voltage of the receiving coil 30, mainly by calculating the asymmetric induced voltage generated by the transmission coil 20 relative to the receiving coil 30. The working principle of the position sensor 50 is as follows: a high-frequency sinusoidal current is passed through the transmitting coil 10, which excites a first high-frequency sinusoidal magnetic field Be that varies with time in space; the transmission coil 20 rotates with the rotor 42 within the first high-frequency sinusoidal magnetic field Be, generating a high-frequency sinusoidal current flowing within the transmission coil 20, and exciting a second high-frequency sinusoidal magnetic field Bt that varies with both time and space in space; the second high-frequency sinusoidal magnetic field Bt passes through the receiving coil 30 in space, exciting an output voltage in the receiving coil 30 that is a superposition of a high-frequency voltage signal and a low-frequency voltage signal; the low-frequency voltage signal in the output voltage is used to determine the rotor position; where high frequency refers to a frequency greater than the target value.

[0037] In an optional example, the position sensor 50 operates as follows:

[0038] First, a high-frequency sinusoidal current that varies with time is passed through the transmitting coil 10. According to Faraday's law of electromagnetic induction, this high-frequency sinusoidal current will excite a high-frequency sinusoidal magnetic field that varies with time in space. For ease of distinction and description, this is referred to as the first high-frequency sinusoidal magnetic field Be in the embodiments of this application.

[0039] Secondly, the high-frequency sinusoidal magnetic field generated by the transmitting coil 10 passes through the transmission coil 20 in space, which will excite a high-frequency sinusoidal voltage that varies with time in the transmission coil 20. Since the transmission coil 20 is a closed loop, a high-frequency sinusoidal current that varies with time will be generated and flow in the transmission coil 20. Moreover, since the transmission coil 20 moves with the rotor 42 of the motor 40, the high-frequency sinusoidal current in the transmission coil 20 not only varies with time but also with space. Thus, the high-frequency sinusoidal current in the transmission coil 20 will also excite a high-frequency sinusoidal magnetic field that varies with both time and space in space. For ease of distinction and description, this is referred to as the second high-frequency sinusoidal magnetic field Bt in the embodiments of this application.

[0040] Furthermore, the high-frequency sinusoidal magnetic field generated by the transmission coil 20, which varies with time and space, passes through the receiving coil 30 in space, and will excite a superimposed high-frequency and low-frequency output voltage in the receiving coil 30. The high-frequency voltage part reflects the high-frequency change of the sinusoidal magnetic field in time, while the low-frequency voltage part reflects the low-frequency change of the sinusoidal magnetic field in space.

[0041] Finally, the output voltage signal in the receiving coil 30 is decoupled by an external processing circuit, and the resulting low-frequency voltage signal reflects the rotor position of the motor 40.

[0042] Optionally, the receiving coil 30 includes two sets of coils with a phase difference of 90° or three sets of coils with a phase difference of 120°. As can be seen from the description of the working principle of the position sensor 50 above, the multiple sets of receiving coils 30 with a phase difference of a set angle can be decoupled after processing by the external processing circuit to obtain two or three signals. This can improve the accuracy of rotor position detection and also detect the direction of rotor 42 movement.

[0043] It should be noted that the position sensor 50 provided in this application embodiment is suitable for both linear motors and rotary motors. Designers can adapt the shape of the transmitting coil 10, transmitting coil 20 and receiving coil 30 accordingly, based on the technical guidance of the working principle of the position sensor 50 and the motion characteristics of linear motors and rotary motors.

[0044] Please refer to the following: Figures 2 to 6 In some embodiments, taking a linear motor as an example, the transmitting coil 10 is a hollow rectangle, and the size of the transmitting coil 20 is half that of the transmitting coil 10. It should be noted that the transmitting coil 20 can initially be aligned with one end of the transmitting coil 10. During the operation of the motor 40, the transmitting coil 20 moves relative to the transmitting coil 10, forming different alignment states with the transmitting coil 10 from one end to the other. For example, Figure 3 The transmitting coil 10 can be designed as several concentric coils, which can be considered as an inductor L. Connecting the equivalent inductance L of the transmitting coil 10 in parallel with a capacitor C will form an LC resonant circuit after applying initial energy. Upon initial excitation, this resonant circuit will generate a high-frequency sinusoidal current ie in the transmitting coil 10, with a frequency f:

[0045]

[0046] Among them, such as Figure 4The projection of the receiving coil 30 in the plane perpendicular to the motor axis is located within the projection range of the transmitting coil 10. The receiving coil 30 includes a positive coil 31 and a negative coil 32 in the shape of a sine wave. The positive coil 31 and the negative coil 32 together form the shape of an infinity symbol, and the length and width of the infinity symbol are approximately equal to the length and width of the transmitting coil 10, respectively.

[0047] Because the receiving coil 30 is very close to both the transmitting coil 10 and the transmitting coil 20, the first high-frequency sinusoidal magnetic field Be generated by the transmitting coil 10 and the second high-frequency sinusoidal magnetic field Bt generated by the transmitting coil 20 both pass through the receiving coil 30 in space. In this embodiment, the receiving coil 30, shaped like an infinity symbol, adopts a series-twisted double-loop design. Thus, the induced voltage ur1 generated in the receiving coil 30 by the first high-frequency sinusoidal magnetic field Be generated by the transmitting coil 10 is... Figure 4 In both loops, the first high-frequency sinusoidal magnetic field Be passing through the transmitting coil 10 will induce voltages ur1-1 and ur1-2 of the same magnitude but opposite polarity. When the loops are connected in series, the induced voltages ur1-1 and ur1-2 cancel each other out, so the total output voltage ur1 of the receiving coil 30 is zero. Furthermore, as... Figure 5 Because the transmission coil 20 is only half the size of the receiving coil 30, it cannot completely cover the double-loop area of ​​the receiving coil 30 regardless of its position during the movement of the rotor 42. Figure 5 The transmitting coil 20 covers a portion of the different areas of the double rings on the left and right sides of the receiving coil 30. The double rings are excited by the second high-frequency sinusoidal magnetic field Bt, which induces voltages ur2-1 and ur2-2 of different magnitudes. The two cannot be completely canceled out, so the total output voltage ur2 of the receiving coil 30 is not zero.

[0048] According to the motion characteristics of the linear motor, when the transmission coil 20 moves left and right relative to the receiving coil 30 as it follows the rotor 42, the areas covered by the second high-frequency sinusoidal magnetic field Bt on the left and right sides of the receiving coil 30 increase and decrease respectively. Therefore, the amplitude of the output high-frequency sinusoidal voltage ur2 of the receiving coil 30 will exhibit a lower-frequency sinusoidal change as the position of the transmission coil 20 changes, such as... Figure 5 The dashed curve of voltage ur2 at the bottom of the middle right figure is shown. Thus, the second high-frequency sinusoidal magnetic field Bt generated by the transmission coil 20 induces a stable output voltage ur2 in the receiving coil 30. After the voltage signal ur2 is decoupled by the external processing circuit, the position of the transmission coil 20, that is, the rotor position information of the linear motor, can be accurately fed back.

[0049] Please see Figure 6The diagram below shows the wiring of the transmitting coil 10, the transmitting coil 20, and the receiving coil 30 in an optional specific example where the motor 40 is a linear motor. The transmitting coil 10 is a hollow rectangle. The transmitting coil 20 is half the size of the transmitting coil 10 and is aligned with one end of the transmitting coil 10. The receiving coil 30 includes three sets of coils shaped like infinity symbols with a phase difference of 120°. It can output three sinusoidal induced voltage signals with a phase difference of 120° using a high-frequency sine wave as the carrier. After decoupling processing, this voltage signal can accurately feed back the position information of the linear motor's actuator.

[0050] Please refer to the following: Figures 7 to 8 In some embodiments, taking a rotary motor as an example, the transmitting coil 10 is a hollow circle, and the outer contour of the transmitting coil 20 includes at least one arc segment circumferentially arranged corresponding to the transmitting coil 10. Based on the rotational characteristics of the rotor 42 in the rotary motor, the transmitting coil 20 is typically designed to be smaller than the transmitting coil 10 and partially aligned with it, taking into account the assembly characteristics of the assembly on the rotor 42 shaft.

[0051] In an optional example, such as Figure 7 The transmission coil 20 includes a sector-shaped portion 21, half the size of the transmitting coil 10, and a connecting portion 22 surrounding the motor shaft. For a rotary motor, the transmitting coil 10 is annular in shape matching the outer contour of the stator 41 of the motor 40, and the transmission coil 20 is correspondingly formed as a sector. The number of transmission coils 20 is equal to the number of pole pairs of the motor 40. If the motor 40 has multiple pole pairs, a sector-shaped transmission coil 20 can be correspondingly provided for each pole pair and connected in series. Figure 8 The transmission coil 20 includes multiple outer arc segments 231 arranged circumferentially corresponding to the transmitting coil 10, multiple inner arc segments 232 arranged circumferentially around the motor shaft, and connecting segments 233 connecting adjacent outer arc segments 231 and inner arc segments 232; wherein the inner arc segments 232 and outer arc segments 231 are staggered in the circumferential direction. Taking a motor 40 with 5 pole pairs as an example, the number of outer arc segments 231 is 5, which are arranged one-to-one with the 5 pole pairs of the motor 40.

[0052] The shape of the receiving coil 30 can be designed as a ring that matches the outer contour shape of the stator 41 of the rotary motor. For example... Figure 7The receiving coil 30 includes three sets of coils with a 120° phase difference, distinguished by green, red, and blue colors respectively. Each set of receiving coils 30 includes a circular positive coil 31 and a negative coil 32, smaller than the transmitting coil 10. The positive coil 31 and negative coil 32 in each set of receiving coils 30 are arranged axially symmetrically. Thus, relative to the transmitting coil 10, the induced voltages generated by the first high-frequency sinusoidal magnetic field Be generated by the transmitting coil 10 can cancel each other out. However, the second high-frequency sinusoidal magnetic field Bt generated by the transmitting coil 20 generates induced voltages ur2-1 and ur2-2 of different magnitudes, which cannot be completely canceled out. These voltages are output by the receiving coil 30 to calculate the rotor position.

[0053] like Figure 8 The receiving coil 30 includes three sets of coils with a phase difference of 120°, distinguished by green, red, and blue colors respectively. Each set of receiving coils 30 includes a positive coil 31 and a negative coil 32 in the shape of a sine wave. The troughs of the positive coil 31 and the negative coil 32 are located on the same ring surrounding the motor shaft, and the peaks are located on the same ring near the inner periphery of the transmitting coil 10. In this embodiment, each set of receiving coils 30 is still symmetrically arranged relative to the transmitting coil 10. The induced voltages generated by the first high-frequency sinusoidal magnetic field Be generated by the transmitting coil 10 can cancel each other out, while the second high-frequency sinusoidal magnetic field Bt generated by the transmitting coil 20 generates induced voltages ur2-1 and ur2-2 of different magnitudes, which cannot be completely canceled out. These voltages are output by the receiving coil 30 to calculate the rotor position.

[0054] In the linear configuration, the receiving coil 30 exhibits a sinusoidal shape. Through coordinate transformation, the trajectory expression of the linear receiving coil 30 can be converted into the trajectory expression of the rotating receiving coil 30. For example... Figure 9 The left-middle figure shows the receiving coil 30 of a sensor for a linear motor with 4 pole pairs. The solid sine curve R(θ) and the dashed sine curve R′(θ) can be represented by Equation 1 and Equation 2, respectively:

[0055] R(θ)=1 / 2(Ro+Ri)+1 / 2(Ro-Ri)sin(pθ); (Formula 1)

[0056] R'(θ)=1 / 2(Ro+Ri)-1 / 2(Ro-Ri)sin(pθ); (Formula 2)

[0057] Where Ro and Ri are the maximum and minimum values ​​relative to the x-axis, respectively.

[0058] like Figure 9 The calculations shown in the middle right figure are as follows: Formula 3 and Formula 4.

[0059] x=R(θ)cos(θ); y=R(θ)sin(θ); (Formula 3)

[0060] x′=R′(θ)cos(θ); y′=R′(θ)sin(θ); (Formula 4)

[0061] The sine and cosine components of R(θ) and R′(θ) can be calculated separately to obtain the receiving coil 30 of a position sensor 50 for a 4-pole rotary motor.

[0062] Please refer to the following: Figures 10 to 12 In the position sensor 50, the wiring design of the transmitting coil 10, the transmitting coil 20, and the receiving coil 30 can be implemented based on a PCB circuit board. In some embodiments, the transmitting coil 10 and the receiving coil 30 are both formed on the sensor stator circuit board 51, and the transmitting coil 20 is formed on the sensor rotor circuit board 52; wherein, the sensor stator circuit board 51 includes multiple wiring layers, the transmitting coil 10 is located on the same wiring layer, and in each group of receiving coils 30, a through hole 511 is provided at the overlapping position of the positive coil 31 and the negative coil 32, and the coil segments located on both sides of the through hole 511 are respectively disposed on different wiring layers by passing through the through hole 511. The transmitting coil 10 and the receiving coil 30 can be integratedly disposed on the same sensor stator circuit board 51, such as... Figure 12 The mechanical frame shape of the sensor stator circuit board 51 (PCB) is roughly the same as the outer contour of the stator 41 of the rotary motor. The transmitting coil 10 includes multiple concentrically arranged annular coils, and the receiving coil 30 includes three groups, each group of receiving coils including coils for sine voltage signals and cosine voltage signals. The sensor stator circuit board 51 is composed of two wiring layers, such as the top wiring layer 512 and the bottom wiring layer 513. The transmitting coil 10 consists of multiple concentric circular coils arranged on the same wiring layer of the sensor stator circuit board 51, such as the top wiring layer 512. The positive coil 31 and negative coil 32 of the receiving coil 30 are respectively wavy, with multiple intersection points between each pair. By setting through holes 511 at each intersection point or in front of the position about to cross, when each receiving coil 30 starts from the starting end and travels on one of the wiring layers on the sensor stator circuit board 51, it passes through the through hole 511 and conducts to another wiring layer to continue traveling. This back and forth is repeated, and wiring is carried back and forth between the two wiring layers, so that the receiving coil 30 is arranged without crossing and conducting.

[0063] The sensor rotor circuit board 52 can be formed in a shape corresponding to the transmission coil 20. In this embodiment, taking the transmission coil 20 designed for the four pole pairs in a rotary motor as an example, the sensor rotor circuit board 52 is a metal plate, and its outer contour is consistent with the outer contour of the transmission coil 20. The metal plate can be regarded as multiple concentric transmission coils 20 stacked, one after another, from the outside to the inside, connected in series, with a through hole 521 in the middle, and is tightly fitted onto the rotor 42 shaft of the motor 40.

[0064] In some embodiments, the position sensor 50 further includes a housing cover 53, within which the sensor stator circuit board 51 is encapsulated. The housing cover 53 has a mounting portion 531 for mounting onto the stator 41. The sensor rotor circuit board 52 is tightly fitted onto the rotor 42 shaft. The housing cover 53 can be a plastic cover. After the sensor stator circuit board 51 is installed in the housing cover 53, potting compound can be used to completely encapsulate and wrap the sensor stator circuit board 51 within the cavity of the housing cover 53, isolating the sensor stator circuit board 51 from contact with the external environment and preventing failure. The sensor stator circuit board 51 can be screwed onto the stator 41 of the motor 40 through the mounting portion 531 on the housing cover 53, specifically including three positioning mounting holes.

[0065] Please see Figures 13 to 15 , Figure 13 This is a schematic diagram showing the wiring of the top wiring layer 512 on the sensor stator circuit board 51 after the arrangement of the transmitting coil 10 and the receiving coil 30 is completed.

[0066] Figure 14 This is a schematic diagram showing the circuit of the bottom wiring layer 513 on the sensor stator circuit board 51 after the receiving coil 30 is arranged. Figure 15 This diagram illustrates the superimposed arrangement of the transmitting coil 10 and receiving coil 30 in the top wiring layer 512 and bottom wiring layer 513 of the sensor stator circuit board 51. As can be seen, the position sensor 50 provided in this embodiment includes a transmitting coil 10, a transmitting coil 20, and a receiving coil 30. By employing the sensor stator circuit board 51 and the sensor rotor circuit board 52 to achieve the required shapes and sizes of the transmitting coil 10, transmitting coil 20, and receiving coil 30, the resulting position sensor 50 has a simple and easily achievable form. The coil wiring design is orderly, neat, and aesthetically pleasing, and it achieves high reliability in detecting the rotor position of the motor 40.

[0067] In another aspect, this application also provides a motor system, including a motor 40 and a position sensor 50 in the embodiments of this application; wherein, the transmitting coil 10 and the receiving coil 30 are fixedly arranged relative to the stator 41, and the transmitting coil 20 is fixedly arranged relative to the rotor 42.

[0068] Among them, motor 40 can be a linear motor or a rotary motor.

[0069] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0070] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A position sensor for a motor, the motor comprising a stator and a rotor, characterized in that, The position sensor includes: A transmitting coil is fixedly disposed relative to the stator, and the transmitting coil includes a plurality of ring-shaped and concentrically arranged coils and a resonant capacitor connected in parallel with the coils; A transmission coil is fixedly disposed relative to the rotor. The size of the transmission coil is smaller than that of the transmitting coil, and the projection of the transmission coil in a plane perpendicular to the motor axis is located within the projection range of the transmitting coil. At least two sets of receiving coils are fixedly arranged relative to the stator, and the phase difference between each set of receiving coils is set by an angle.

2. The position sensor according to claim 1, characterized in that, The receiving coil includes two sets of coils with a phase difference of 90°, or three sets of coils with a phase difference of 120°.

3. The position sensor according to claim 1, characterized in that, The motor is a linear motor; The transmitting coil is a hollow rectangle, and the size of the transmitting coil is half that of the transmitting coil.

4. The position sensor according to claim 3, characterized in that, The projection of the receiving coil in a plane perpendicular to the motor axis is located within the projection range of the transmitting coil. The receiving coil includes a positive coil and a negative coil in the shape of a sine wave. The positive coil and the negative coil together form the shape of an infinity symbol, and the length and width of the infinity symbol are approximately equal to the length and width of the transmitting coil, respectively.

5. The position sensor according to claim 1, characterized in that, The motor is a rotary motor; The transmitting coil is a hollow circle, and the outer contour of the transmitting coil includes at least one arc segment arranged circumferentially corresponding to the transmitting coil.

6. The position sensor according to claim 5, characterized in that, The transmission coil includes a sector-shaped portion that is half the size of the transmitting coil and a connecting portion arranged around the motor shaft.

7. The position sensor according to claim 5, characterized in that, The transmission coil includes a plurality of outer arc segments arranged circumferentially corresponding to the transmitting coil, a plurality of inner arc segments arranged circumferentially around the motor shaft, and a connecting segment connecting adjacent outer arc segments and inner arc segments. The inner arc segment and the outer arc segment are staggered in the circumferential direction.

8. The position sensor according to claim 5, characterized in that, The receiving coil includes three sets of coils with a phase difference of 120°; Each set of receiving coils includes a positive coil and a negative coil, both smaller than the transmitting coil, arranged in annular shape. The positive and negative coils in each set of receiving coils are axially symmetrical. Alternatively, each set of receiving coils includes a positive coil and a negative coil in the shape of a sine wave, with the troughs of the positive and negative coils located on the same annulus surrounding the motor shaft, and the peaks located on the same annulus near the inner periphery of the transmitting coil.

9. The position sensor according to any one of claims 1 to 8, characterized in that, The transmitting coil and the receiving coil are both formed on the sensor stator circuit board, and the transmitting coil is formed on the sensor rotor circuit board; The sensor stator circuit board includes multiple wiring layers. The transmitting coil is located on the same wiring layer. The receiving coil includes a positive coil and a negative coil in the shape of a sine wave. In each group of receiving coils, a through hole is provided at the overlapping position of the positive coil and the negative coil. The coil segments located on both sides of the through hole are respectively located on different wiring layers by passing through the through hole.

10. The position sensor according to claim 9, characterized in that, It also includes a housing cover, in which the sensor stator circuit board is encapsulated and disposed, and the housing cover is provided with a mounting portion for assembly onto the stator; The sensor rotor circuit board is tightly fitted onto the rotor shaft.

11. The position sensor according to any one of claims 1 to 8, characterized in that, A high-frequency sinusoidal current is passed through the transmitting coil, and the high-frequency sinusoidal current excites a first high-frequency sinusoidal magnetic field that varies with time in space. The transmission coil rotates with the rotor within the first high-frequency sinusoidal magnetic field, generating a high-frequency sinusoidal current flowing within the transmission coil, and spatially exciting a second high-frequency sinusoidal magnetic field that changes simultaneously with time and space. The second high-frequency sinusoidal magnetic field passes through the receiving coil in space, exciting an output voltage in the receiving coil that is a superposition of a high-frequency voltage signal and a low-frequency voltage signal; the low-frequency voltage signal in the output voltage is used to determine the position of the rotor. Among them, high frequency refers to a frequency greater than the target value.

12. A motor system, characterized in that, It includes a motor and a position sensor as described in any one of claims 1 to 11; wherein the transmitting coil and the receiving coil are fixedly disposed relative to the stator, and the transmitting coil is fixedly disposed relative to the rotor.

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