Sensor for radially detecting position of rotor of eddy current motor

Abstract

The utility model discloses a sensor for radially detecting the position of an eddy current motor rotor, which comprises an outer rotor motor hub, an outer rotor motor rotor and an eddy current sensor, the outer rotor motor rotor is positioned in the outer rotor motor hub, and the eddy current sensor is fixed on a shell of an outer rotor motor. A detection window is formed in the position, corresponding to the eddy current sensor, of the outer rotor motor hub; the eddy current sensor comprises a flexible circuit board and an ASIC chip. The beneficial effects of the utility model are that: 1, the eddy current sensor adopting the radial detection mode can successfully solve the problem of axial space design of a motor, is beneficial to reduction of the axial size, and further improves the electric drive power density; 2, the eddy current sensor adopting the radial detection mode does not need an independent metal target wheel, and the window feature on the rotating hub of the motor rotor can be used as a detected object, so that the number and weight of parts can be reduced, and meanwhile, the system cost can be reduced;

Description

Technical Field

[0001] The utility model relates to the technical field of motor rotor position detection, in particular to a sensor for radially detecting the rotor position of an eddy current motor. Background Art

[0002] Currently, most eddy current sensors on the market are used in motors to detect the real-time phase of the motor rotor. They are axially installed, occupying the axial space of the motor, which hinders the further reduction of the axial size of the motor or the increase of the power density. In addition, the normal operation of the axial eddy current sensor requires a separate metal target wheel, which is difficult to integrate into other parts. Utility Model Content

[0003] In order to solve the above problems, the present invention provides a sensor for radially detecting the rotor position of an eddy current motor. The present invention is implemented through the following technical solutions.

[0004] A sensor for radially detecting the rotor position of an eddy current motor comprises an outer rotor motor hub, an outer rotor motor rotor and an eddy current sensor. The outer rotor motor rotor is inserted into the outer rotor motor hub, and the outer rotor motor rotor and the outer rotor motor hub rotate synchronously. The eddy current sensor is fixed to the outer rotor motor housing. Detection windows are uniformly opened on the outer rotor motor hub at positions corresponding to the eddy current sensors.

[0005] The eddy current sensor includes a flexible circuit board and an ASIC chip; an eddy current coil is etched on the flexible circuit board, and the eddy current coil includes an excitation coil and three groups of induction coils with a phase difference of 120°, and the excitation coil and the induction coil are connected to the ASIC chip.

[0006] Preferably, the length of the detection window is not less than 8 mm, the depth of the detection window is not less than 6 mm, and the position of the detection window corresponds to the position of the magnetic pole of the motor.

[0007] Preferably, a plastic shell is fixed to the outer shell of the outer rotor motor, and the side of the plastic shell close to the outer rotor motor hub is arc-shaped. A soft board that matches the arc shape of its bottom is riveted to the inside of the plastic shell. The flexible circuit board and the ASIC chip are SMT on the soft board. The pins of the ASIC chip are connected to the wiring harness through metal terminals. The soft board, metal terminals and wiring harness are located in the plastic shell and are encapsulated by epoxy resin. The ASIC chip is connected to the host computer ECU.

[0008] Preferably, pins 1-3 of the ASIC chip are each connected to an induction coil L R x, induction coil L R The other ends of x are connected to each other, and the excitation coil L TThe two ends of x are connected to the 4th and 6th pins of the ASIC chip respectively. The 7th and 10th pins of the ASIC chip are connected to the input of the host ECU respectively. The power output of the host ECU is connected in parallel with two pull-up resistors R PU And the ASIC chip's pin 11, one of the pull-up resistors R PU The other end is connected to pin 7 of the ASIC chip, and another pull-up resistor R PU The other end is connected to pin 10 of the ASIC chip, pins 5, 16, 12, 14, and 15 of the ASIC chip are grounded, and the ground end of the host ECU is also grounded.

[0009] Preferably, a capacitor C is connected between pins 1-3 of the ASIC chip. IN Ground, pins 4 and 6 of the ASIC chip are connected to the ground through capacitor C LC Ground, pin 11 of the ASIC chip is connected to the ground through capacitor C VS Grounding, pins 7-10 of the ASIC chip are grounded through capacitor C1, pins 7 and 10 of the ASIC chip are also grounded through capacitor C3, and pin 13 of the ASIC chip is grounded through capacitor C2.

[0010] Preferably, pins 1-3 of the ASIC chip are induction coils L R The voltage input port of x, pins 4 and 6 of the ASIC chip are the excitation coil L T x's output and input ports, pins 5, 12, and 14-16 of the ASIC chip are ground terminals, pin 11 of the ASIC chip is the power input terminal, pins 7 and 8 of the ASIC chip are the output and input terminals of the sine voltage respectively, and pins 10 and 9 of the ASIC chip are the output and input terminals of the cosine voltage respectively.

[0011] The beneficial effects of the utility model are as follows:

[0012] 1. This radial detection method of eddy current sensors can successfully solve the axial space problem of motor design, which is conducive to reducing the axial size and further improving the power density of electric drives.

[0013] 2. This radial detection method of the eddy current sensor does not require a separate metal target wheel. The window feature on the motor rotor hub can be used as the detection object, which helps to reduce the number of parts and weight, while also reducing system costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the specific implementation methods. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 : A schematic structural diagram of a sensor for radially detecting the rotor position of an eddy current motor according to the present invention;

[0016] Figure 2 : Exploded view of the eddy current sensor of the present invention;

[0017] Figure 3 : Schematic diagram of the circuit principle of the eddy current sensor described in the utility model;

[0018] Figure 4 : The relationship diagram between the rotor position and the output voltage of the utility model;

[0019] Figure 5 : Working process diagram of a sensor for radially detecting the rotor position of an eddy current motor described in the utility model.

[0020] The reference numerals are as follows:

[0021] 100-outer rotor motor hub, 200-outer rotor motor rotor, 300-eddy current sensor, 301-plastic housing, 302-flexible board, 303-metal terminal, 304-wiring harness, 305-epoxy resin, 400-detection window. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] like Figure 1-5 As shown, a sensor for radially detecting the rotor position of an eddy current motor includes an outer rotor motor hub 100, an outer rotor motor rotor 200, and an eddy current sensor 300. The outer rotor motor rotor 200 is inserted into the outer rotor motor hub 100. The outer rotor motor rotor 200 and the outer rotor motor hub 100 rotate synchronously. The eddy current sensor 300 is fixed to the outer rotor motor housing. Detection windows 400 are uniformly opened on the outer rotor motor hub 100 at positions corresponding to the eddy current sensors 300.

[0024] The eddy current sensor 300 includes a flexible circuit board and an ASIC chip; an eddy current coil is etched on the flexible circuit board, and the eddy current coil includes an excitation coil and three sets of induction coils with a phase difference of 120°. The excitation coil and the induction coil are connected to the ASIC chip.

[0025] Furthermore, the length of the detection window 400 is not less than 8 mm, the depth of the detection window 400 is not less than 6 mm, and the position of the detection window 400 corresponds to the position of the magnetic pole of the motor.

[0026] Furthermore, a plastic shell 301 is fixed to the outer shell of the outer rotor motor. The side of the plastic shell 301 close to the outer rotor motor hub 100 is arc-shaped. The inside of the plastic shell 301 is riveted to a soft board 302 that matches the arc of its bottom. The flexible circuit board and the ASIC chip are SMT-mounted on the soft board 302. The pins of the ASIC chip are connected to the wiring harness 304 through the metal terminals 303. The soft board 302, the metal terminals 303 and the wiring harness 304 are located in the plastic shell 301 and are encapsulated by epoxy resin 305. The ASIC chip is connected to the host computer ECU.

[0027] Furthermore, pins 1-3 of the ASIC chip are each connected to an induction coil L R x, induction coil L R The other ends of x are connected to each other, and the excitation coil L T The two ends of x are connected to the 4th and 6th pins of the ASIC chip respectively. The 7th and 10th pins of the ASIC chip are connected to the input of the host ECU respectively. The power output of the host ECU is connected in parallel with two pull-up resistors R PU And the ASIC chip's pin 11, one of the pull-up resistors R PU The other end is connected to pin 7 of the ASIC chip, and another pull-up resistor R PU The other end is connected to pin 10 of the ASIC chip, pins 5, 16, 12, 14, and 15 of the ASIC chip are grounded, and the ground end of the host ECU is also grounded.

[0028] Furthermore, capacitor C is connected between pins 1-3 of the ASIC chip. IN Ground, pins 4 and 6 of the ASIC chip are connected to the ground through capacitor C LC Ground, pin 11 of the ASIC chip is connected to the ground through capacitor C VS Grounding, pins 7-10 of the ASIC chip are grounded through capacitor C1, pins 7 and 10 of the ASIC chip are also grounded through capacitor C3, and pin 13 of the ASIC chip is grounded through capacitor C2.

[0029] Furthermore, pins 1-3 of the ASIC chip are induction coils L R The voltage input port of x, pins 4 and 6 of the ASIC chip are the excitation coil L T x's output and input ports, pins 5, 12, and 14-16 of the ASIC chip are ground terminals, pin 11 of the ASIC chip is the power input terminal, pins 7 and 8 of the ASIC chip are the output and input terminals of the sine voltage respectively, and pins 10 and 9 of the ASIC chip are the output and input terminals of the cosine voltage respectively.

[0030] A specific embodiment of the present invention is:

[0031] The outer rotor motor in this application includes a fixed outer casing, the outer rotor motor rotor 200 is inserted into the outer rotor motor hub 100, the outer rotor motor rotor 200 and the outer rotor motor hub 100 rotate synchronously in the outer casing, and the eddy current sensor 300 is fixed on the outer casing of the outer rotor motor. The eddy current sensor 300 measures the rotational speed of the outer rotor motor rotor 200 and the outer rotor motor hub 100 and the real-time phase relative to the target window, where the target window is the installation window of the eddy current sensor 300.

[0032] The circuit connection of the eddy current sensor 300 is as follows Figure 3 shown.

[0033] like Figure 4 and Figure 5 As shown, the host computer ECU inputs a 5V DC power supply to the ASIC chip. When the excitation coil receives power and works normally, it will generate a periodically changing electric field with a frequency of 3.5MHz, thereby generating a periodically changing excitation magnetic field in the area covered by the excitation coil. When the outer rotor motor hub 100 with a detection window 400 passes through the excitation coil, eddy currents will be generated due to the eddy current effect. The eddy currents will generate a reverse magnetic field to hinder the change of the original excitation magnetic field. The excitation magnetic field and the reverse magnetic field will be detected by the three sets of induction coils to generate a periodic electric field. This periodically changing electric field will be converted into a change in voltage amplitude inside the ASIC chip. The ASIC chip will filter and demodulate at the same time, and then transmit it to the host computer ECU. The host computer ECU receives the sine and cosine signals and performs software calculations to obtain the real-time position of the motor rotor, thereby realizing precise control of the motor.

[0034] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A sensor for radially detecting the rotor position of an eddy current motor, characterized in that: The invention comprises an outer rotor motor hub (100), an outer rotor motor rotor (200) and an eddy current sensor (300), wherein the outer rotor motor rotor (200) is plugged into the outer rotor motor hub (100), the outer rotor motor rotor (200) and the outer rotor motor hub (100) rotate synchronously, the eddy current sensor (300) is fixed on the outer rotor motor housing, and detection windows (400) are uniformly provided on the outer rotor motor hub (100) at positions corresponding to the eddy current sensors (300); The eddy current sensor (300) comprises a flexible circuit board and an ASIC chip; an eddy current coil is etched on the flexible circuit board, the eddy current coil comprises an excitation coil and three groups of induction coils with a phase difference of 120 degrees, and the excitation coil and the induction coil are connected to the ASIC chip.

2. A sensor for radially detecting the rotor position of an eddy current motor according to claim 1, characterized in that: The length of the detection window (400) is not less than 8 mm, the depth of the detection window (400) is not less than 6 mm, and the position of the detection window (400) corresponds to the position of the magnetic pole of the motor.

3. The sensor for radially detecting the rotor position of an eddy current motor according to claim 1, characterized in that: A plastic shell (301) is fixedly connected to the outer shell of the outer rotor motor. The side of the plastic shell (301) close to the outer rotor motor hub (100) is arc-shaped. A soft board (302) that matches the arc shape of the bottom of the plastic shell (301) is riveted inside the plastic shell (301). The flexible circuit board and the ASIC chip are SMT-mounted on the soft board (302). Each pin of the ASIC chip is connected to a wiring harness (304) through a metal terminal (303). The soft board (302), the metal terminal (303) and the wiring harness (304) are located in the plastic shell (301) and are encapsulated by epoxy resin (305). The ASIC chip is connected to an upper computer ECU.

4. The sensor for radially detecting the rotor position of an eddy current motor according to claim 3, characterized in that: Pins 1-3 of the ASIC chip are each connected to an induction coil L R x, induction coil L R The other ends of x are connected to each other, and the excitation coil L T The two ends of x are connected to the 4th and 6th pins of the ASIC chip respectively. The 7th and 10th pins of the ASIC chip are connected to the input of the host ECU respectively. The power output of the host ECU is connected in parallel with two pull-up resistors R PU And the ASIC chip's pin 11, one of the pull-up resistors R PU The other end is connected to pin 7 of the ASIC chip, and another pull-up resistor R PU The other end is connected to pin 10 of the ASIC chip, pins 5, 16, 12, 14, and 15 of the ASIC chip are grounded, and the ground end of the host computer ECU is also grounded.

5. The sensor for radially detecting the rotor position of an eddy current motor according to claim 4, characterized in that: The capacitor C is connected between pins 1-3 of the ASIC chip. IN Ground, pins 4 and 6 of the ASIC chip are connected to the ground through capacitor C LC Ground, pin 11 of the ASIC chip is connected to the ground through capacitor C VS Grounding, pins 7-10 of the ASIC chip are grounded through capacitor C1, pins 7 and 10 of the ASIC chip are also grounded through capacitor C3, and pin 13 of the ASIC chip is grounded through capacitor C2.

6. The sensor for radially detecting the rotor position of an eddy current motor according to claim 5, characterized in that: Pins 1-3 of the ASIC chip are induction coils L R The voltage input port of x, pins 4 and 6 of the ASIC chip are the excitation coil L T x's output and input ports, pins 5, 12, and 14-16 of the ASIC chip are ground terminals, pin 11 of the ASIC chip is the power input terminal, pins 7 and 8 of the ASIC chip are the output and input terminals of the sine voltage respectively, and pins 10 and 9 of the ASIC chip are the output and input terminals of the cosine voltage respectively.

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