CN216290573U

CN216290573U - Permanent magnet brushless motor rotor position detection mechanism with built-in drive circuit

Info

Publication number: CN216290573U
Application number: CN202122986986.2U
Authority: CN
Inventors: 许明有; 李兴龙
Original assignee: Hangzhou Yingjishi Electric Co ltd
Current assignee: Hangzhou Yingjishi Electric Co ltd
Priority date: 2021-12-01
Filing date: 2021-12-01
Publication date: 2022-04-12
Anticipated expiration: 2031-12-01

Abstract

The utility model discloses a permanent magnet brushless motor rotor position detection mechanism with a built-in drive circuit and an algorithm, wherein the structure comprises a built-in drive circuit board, a linear Hall sensor, planar induction magnetic steel, a motor rotor and a motor stator, and the permanent magnet brushless motor rotor position detection mechanism is characterized in that the built-in drive circuit board is arranged in the permanent magnet brushless motor and is used for driving the motor to run; and at least two linear Hall sensors are used for sensing the magnetic field change of the plane sensing magnetic steel. The utility model provides the device and the method for detecting the position of the rotor of the permanent magnet brushless motor based on the built-in driving circuit, which not only have more compact structure, but also save the installation cost and the wiring harness cost of the external driving circuit board by the aid of the built-in driving circuit board, and have very good practical value.

Description

Permanent magnet brushless motor rotor position detection mechanism with built-in drive circuit

Technical Field

The utility model belongs to the field of permanent magnet brushless motors, relates to a permanent magnet brushless motor structure with a built-in driving circuit, and particularly relates to a rotor position detection mechanism based on linear Hall induction.

Background

The traditional permanent magnet brushless motor basically adopts three switch Hall sensors to detect the angle of a motor rotor; and an external driving circuit is generally adopted to control the operation of the permanent magnet brushless motor. But has several disadvantages: (a) the switch Hall sensor has low angular resolution for detecting the position of the rotor, only provides 6 discrete position information in one electrical cycle, and cannot meet the requirement of vector control on the position information of the rotor with high resolution; (b) although the 'permanent magnet brushless motor vector control algorithm based on the switch hall sensor' also exists in the industry, the algorithm generally requires stable motor rotating speed and small load impact, and is mostly applied to fan application occasions, and when the application occasions require the motor to have output capacity of low speed, large torque and high dynamic response, the algorithm cannot meet the application requirements; (c) the external driving circuit needs to increase the cost of a Hall sensing circuit board, a motor winding, a wiring harness of a Hall signal, an installation shell of the external driving circuit and the like, and the external driving circuit is not compact in space in some application occasions.

Chinese patent No. CN 113162333 a discloses a magnetic ring encoder structure of a brushless motor and a brushless motor, including a magnetic ring and a linear hall sensor. The magnetic ring is arranged on a rotor shaft in the brushless motor and can synchronously rotate along with the rotor shaft of the motor; the linear Hall sensors are at least two and are arranged on the circuit board, the circuit board is provided with a through hole, and the motor rotor shaft penetrates through the through hole of the circuit board. The entire patent is not described in terms of a driving circuit, and it is assumed that the circuit board is only used for mounting the linear hall sensor and its peripheral circuits, does not contain an internal driving circuit, and needs an external driving circuit for driving the operation of the motor.

Above-mentioned technical scheme has designed one set of brushless motor rotor position detection mechanism based on magnetic ring encoder structure, and this kind of structure does not have internal integrated motor drive circuit, needs the pencil through motor winding and hall signal to realize the electricity between motor and the external drive circuit and is connected, and external drive circuit then needs extra mounted position. The motor and the driving circuit thereof in the scheme have relatively larger occupied space and higher cost; compared with the planar induction magnetic steel, the magnetic ring structure is not compact enough, and the cost is relatively high.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems, and provides a rotor position detection structure of a permanent magnet brushless motor based on an internal drive circuit, which is more compact in structure, and the internal drive circuit board saves the installation cost and the wiring harness cost of an external drive circuit board, and has very good practical value.

In order to achieve the purpose, the utility model adopts the following technical scheme:

a permanent magnet brushless motor rotor position detection mechanism with a built-in drive circuit comprises a built-in drive circuit board, a linear Hall sensor, planar induction magnetic steel, a motor rotor and a motor stator, and is characterized in that the built-in drive circuit board is arranged in the permanent magnet brushless motor and used for driving the motor to run; the linear Hall sensors are at least two and are used for sensing the magnetic field change of the planar induction magnetic steel; the planar induction magnetic steel is arranged on a shaft of the motor rotor and synchronously rotates along with the rotor shaft to generate a sinusoidal alternating magnetic field; and the three-phase winding coil of the motor stator is electrically connected with three metal joints of the built-in driving circuit board.

On the basis of the scheme, the plane where the linear Hall sensor is located is parallel to the plane where the planar induction magnetic steel is located, the plane where the planar induction magnetic steel is located is perpendicular to the rotor axial lead of the motor rotor, and the cylindrical circular lead of the planar induction magnetic steel is coincident with the rotor axial lead of the motor rotor.

On the basis of the scheme, the fixing support of the motor stator is provided with the insulating layer, and the built-in driving circuit board is arranged on the motor stator through the supporting columns and the buckles on the fixing support.

On the basis of the scheme, the outer contour of the built-in driving circuit board is circular, the built-in driving circuit board is perpendicular to the axis of the motor rotor, and the circle center of the built-in driving circuit board coincides with the axis of the motor rotor.

On the basis of the scheme, the linear Hall sensors are packaged by adopting a patch and are arranged on the built-in driving circuit board, the linear Hall sensors are arranged on the circumference which takes the axial lead of the motor rotor as the center of a circle, and the angle difference value of two adjacent linear Hall sensors on the circumference is 90 degrees.

On the basis of the scheme, the planar induction magnetic steel is cylindrical, the planar induction magnetic steel is a pair of polar magnetic steels, and the planar induction magnetic steel is fixedly connected with a rotor shaft of the motor rotor.

On the basis of the scheme, an angle difference exists between the N-pole magnetic field direction of the planar induction magnetic steel and the N-pole magnetic field direction of the main magnetic field of the motor rotor.

The utility model has the advantages that:

1. a built-in driving circuit board is integrated in the motor and is electrically connected with a motor stator coil through three metal insertion sheets on the circuit board; through support column and the buckle on the motor stator fixed bolster, fix the circuit board on motor stator. The mounting structure is low in cost, compact in structure and small in occupied space, and can meet the requirement of mounting accuracy between the circuit board and the motor stator.

The linear Hall sensor is packaged by adopting a patch and is attached to the built-in driving circuit board. Through the paster welding process, the installation accuracy requirement between the linear Hall sensor and the circuit board can be ensured, and further, the installation accuracy requirement between the linear Hall sensor and the planar induction magnetic steel is ensured.

The planar induction magnetic steel adopts a pair of small-sized polar cylindrical magnetic steels, and compared with a magnetic ring structure, the planar induction magnetic steel has the advantages of low cost, simplicity in installation, small size and the like. Moreover, the magnetic ring structure requires: the number of pole pairs of the magnetic ring is matched with the number of pole pairs of a main magnetic field of a motor rotor, a certain corresponding relation is formed, and the angle of the circumferential position of the linear Hall sensor on the circuit board is changed along with the change of the number of pole pairs of the magnetic ring; the planar induction magnetic steel with a pair of polar magnetic fields is adopted, the number of pole pairs of a main magnetic field of a motor rotor is not limited at all, and the angle relation of two linear Hall sensors on the circumference is determined and not changed.

Drawings

Fig. 1 is a schematic structural diagram of a permanent magnet brushless motor with a built-in driving circuit according to the present invention.

In the figure, a built-in driving circuit board 1, a linear hall sensor 2, a planar induction magnetic steel 3, a motor rotor 4 and a motor stator 5 are arranged.

Detailed Description

Technical solutions of embodiments of the present invention are explained and explained below with reference to drawings of embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of protection of the present patent.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted" and "connected" are to be interpreted broadly, e.g., as being detachably connected or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be specifically understood by those of ordinary skill in the art.

In the description of the present invention, it should be noted that, unless explicitly specified or limited otherwise, the term "ac amplitude, dc offset, and rotor initial position compensation angle of two linear hall signals included in the rotor initial position parameter" should be understood in a broad sense, and other parameters of "ac amplitude, dc offset, and rotor initial position compensation angle of two linear hall signals" can be obtained through simple operations (for example, ac amplitude and dc offset of two linear hall signals can be obtained through calculation through maximum and minimum values of the linear hall signals; for example, rotor initial position compensation angle can be expressed in a trigonometric function form of an angle) should be regarded as another expression form of "rotor initial position parameter", and thus should not be construed as a limitation to the present invention.

The embodiment of the utility model provides a rotor position detection mechanism of a permanent magnet brushless motor with a built-in drive circuit. The permanent magnet brushless motor comprises a shell, a stator component, a rotor shaft and other components, wherein the stator component, the rotor component and the rotor shaft are arranged in the shell; the topology of the permanent magnet brushless motor driving circuit is a public structure, and therefore no specific circuit drawing is provided in the present application.

The utility model provides a rotor position detection mechanism of a permanent magnet brushless motor with a built-in driving circuit, which detects the magnetic field change of planar induction magnetic steel arranged on a rotor shaft of the permanent magnet brushless motor through two paths of linear Hall sensors to obtain the rotor position and the rotating speed of the motor.

The two linear Hall sensors 2 are packaged by adopting a patch and are attached to the built-in driving circuit board 1, and the circuit board is vertical to the axial lead of the rotor shaft, so that the distances from the two linear Hall sensors 2 to the planar induction magnetic steel 3 are equal. The two linear Hall sensors 2 are distributed on the circumference which takes the axial lead of the rotor shaft as the center of a circle, and the adopted plane induction magnetic steel 3 is one pair of polar magnetic steel, so the two linear Hall sensors 2 are distributed on the circumference at a mechanical angle of 90 degrees. The magnetic field induced by the linear hall sensor 2 is an axial magnetic field. The linear Hall sensor 2 is installed on the circuit board by adopting a patch welding process, so that the installation precision of the linear Hall sensor 2 is ensured, and the error of rotor position detection is reduced.

The outer contour of the built-in driving circuit board 1 and the inner wall of the motor shell are both circular or cylindrical, the difference value of the radiuses of the two circles or the two cylinders is only 0.2-0.4 mm, the concentricity between the circuit board and the motor rotor shaft is ensured, and the equal or nearly equal distance between the two linear Hall sensors 2 and the axial lead of the rotor shaft is further ensured; be equipped with insulating material fixed bolster on motor stator 5, through support column and the buckle on the fixed bolster, fix the circuit board on motor stator 5 to ensure that the plane of circuit board place is parallel with plane induction magnet steel 3 place plane, and then guaranteed that two way linear hall sensor 2 and plane induction magnet steel 3 place planar distance equals or is close to equals.

The planar induction magnetic steel 3 adopts a pair of magnetic steel poles with the diameter of 6.0mm, and is fixedly bonded with the mounting base by glue; and a threaded fastening structure is adopted between the mounting base of the planar induction magnetic steel 3 and the rotor shaft of the motor rotor 5. The installation process is compact in structure and convenient to assemble, installation accuracy between the planar induction magnetic steel and the rotor shaft can be guaranteed, and errors of rotor position detection are reduced.

The two paths of linear Hall sensors 2 and the built-in drive circuit are integrated on the same circuit board, so that signals of the linear Hall sensors 2 can be input to an embedded single chip microcomputer ADC interface on the built-in drive circuit only through simple resistance-capacitance low-pass filtering, analog signals of the linear Hall sensors 2 are converted into digital signals of the embedded single chip microcomputer, and calculation of a rotor position detection algorithm is carried out. The rotor position detection algorithm of the present invention is explained in detail below:

when the built-in driving circuit is powered on for the first time, a rotor initial position parameter detection algorithm must be operated, so that rotor initial position parameters are obtained and stored in the power-down storage circuit; when the built-in driving circuit is not powered on for the first time, the 'yes' or 'no' operation of the rotor initial position parameter detection algorithm can be selected according to the control requirement.

The power-down storage circuit can be an internal integrated circuit of the embedded singlechip or an external circuit of the embedded singlechip, such as an external EEPROM chip; the initial position parameters of the rotor comprise alternating current amplitude values (and), direct current bias (and) and initial position compensation angles (and) of two paths of linear Hall signals. The specific implementation steps of the rotor initial position parameter detection algorithm are as follows:

(a) when the built-in driving circuit is electrified for the first time, the motor is dragged to operate according to a permanent magnet brushless motor I/F starting control strategy based on vector control (FOC control); controlling quadrature axis current and controlling direct axis current; the preset motor rotating speed curve outputs the rotor electrical angular speed and the rotor mechanical angular speed, the rotor angular speed is subjected to integral operation to obtain a rotor position electrical angle and a rotor position mechanical angle, and the rotor position electrical angle and the rotor position mechanical angle satisfy the following relations:

(b) collecting two paths of linear Hall output signals which are mutually different by 90 degrees, respectively obtaining a maximum sum and a minimum sum, and further performing per-unit processing on the two paths of linear Hall output signals, wherein the processing result is as follows:

wherein, it is the result of per-unit processing; is a direct current bias; is the ac amplitude. DC bias, which can be expressed as

The AC amplitude can be expressed as

Due to the fact that installation errors of all parts are overlapped or two paths of Hall signal detection circuits are inconsistent, the alternating current amplitude and the direct current offset of two paths of linear Hall signals are inconsistent, and therefore rotor position detection errors can be caused.

(c) When the motor operates in a constant-speed forward rotation mode, acquiring two paths of linear Hall signal outputs and a first group of angle compensation angles, wherein the angle compensation angles are respectively a sum; when the motor runs in a constant speed reverse rotation mode, two paths of linear Hall signal outputs and a second group of angle compensation angles are obtained and respectively equal. Because the load torque of the motor is not zero, the quadrature axis current direction and the motor rotor quadrature axis direction (namely, the D axis direction) can not be completely overlapped, so that the motor needs to be in constant-speed forward motion and in constant-speed reverse motion, angle compensation angles are respectively obtained, and are added and averaged, and finally, an initial position compensation angle of a rotor position detection algorithm is obtained, as follows:

(d) and after the operation is finished, the automatic control motor is stopped, and the initial position parameters of the rotor are stored in the power-down storage circuit. And according to the control requirement, the motor can be selected to enter a normal running mode or be continuously in a stop state.

When the built-in driving circuit is not electrified for the first time, the normal operation mode of the motor can be directly entered without operating a rotor initial position parameter detection algorithm; in a normal operation mode of the motor, only a rotor initial position compensation algorithm and a rotor position decoding algorithm need to be operated, and the rotor position and rotating speed information obtained through calculation can be used for a vector control (FOC) algorithm of the permanent magnet brushless motor. The specific implementation steps of the rotor initial position compensation algorithm and the rotor position decoding algorithm are as follows:

(a) collecting two linear Hall output signal sums which are different from each other by 90 degrees of mechanical angle, reading 'rotor initial position parameters' in a power failure storage circuit, and performing per-unit processing on the linear Hall output signal sums according to alternating current amplitude values (sum) and direct current offset (sum) of the two linear Hall signals to obtain per-unit result sums.

(b) And reading 'initial position parameters of a rotor' in the power-down storage circuit, and performing coordinate transformation on the per-unit result sum of the two linear Hall signals according to the initial position compensation angle sum of the rotor to obtain the angle compensation result sum of the two linear Hall signals. The coordinate transformation method comprises the following steps:

wherein, the coefficients; is the orthogonal deviation angle (general) of two linear hall signals, so the coefficient and coordinate transformation method is further simplified as follows:

the above two steps (i.e., step a and step b) implement a rotor initial position compensation algorithm.

(c) And (3) inputting the angle compensation results of the two paths of linear Hall signals into a quadrature phase-locked loop (PLL) algorithm, and calculating to obtain the position and the rotating speed of the motor rotor. The quadrature phase-locked loop algorithm has a disclosed structure and therefore no specific schematic of the algorithm is provided within this application.

The position and the rotating speed of the motor rotor are respectively a mechanical angle and a mechanical angular speed, and when the motor rotor is used for vector control of the permanent magnet synchronous motor, the motor rotor needs to be converted into an electric angle and an electric angular speed form according to the number of pole pairs of the motor rotor.

The core algorithm of the built-in driving circuit in the embedded single chip at least comprises the following steps: a rotor position detection algorithm and a permanent magnet brushless motor vector control (FOC control) algorithm. The vector control (FOC control) algorithm of the permanent magnet brushless motor has a public functional block diagram and an implementation method, so that detailed explanation is not provided in the application.

In summary, the present invention discloses a method for detecting a rotor position of a permanent magnet brushless motor with a built-in driving circuit, which has the following advantages compared with the prior art: the whole machine has compact structure, convenient installation, lower cost, easy realization of the algorithm of rotor position detection and good practical value.

The specific embodiments described herein are merely illustrative of the spirit of the utility model. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the utility model as defined in the appended claims.

Claims

1. A permanent magnet brushless motor rotor position detection mechanism with a built-in drive circuit comprises a built-in drive circuit board (1), a linear Hall sensor (2), a planar induction magnetic steel (3), a motor rotor (4) and a motor stator (5), and is characterized in that the built-in drive circuit board (1) is installed inside a permanent magnet brushless motor and used for driving the motor to run; the linear Hall sensors (2) are at least two and are used for sensing the magnetic field change of the plane sensing magnetic steel (3); the planar induction magnetic steel (3) is arranged on a shaft of the motor rotor (4) and synchronously rotates along with the rotor shaft to generate a sine alternating magnetic field; and the three-phase winding coil of the motor stator (5) is electrically connected with three metal joints of the built-in driving circuit board (1).

2. The mechanism of claim 1, wherein the mechanism comprises: the plane of the linear Hall sensor (2) is parallel to the plane of the plane induction magnetic steel (3), the plane of the plane induction magnetic steel (3) is perpendicular to the rotor axial lead of the motor rotor, and the cylindrical circular lead of the plane induction magnetic steel (3) coincides with the rotor axial lead of the motor rotor.

3. The mechanism of claim 1, wherein the mechanism comprises: the fixing support of the motor stator (5) is provided with an insulating layer, and the built-in driving circuit board (1) is arranged on the motor stator (5) through a supporting column and a buckle on the fixing support.

4. The mechanism of claim 1, wherein the mechanism comprises: the external contour of the built-in driving circuit board (1) is circular, the built-in driving circuit board (1) is perpendicular to the axis of the motor rotor (4), and the circle center of the built-in driving circuit board coincides with the axis of the motor rotor (4).

5. The mechanism of claim 1, wherein the mechanism comprises: the linear Hall sensors (2) are packaged by adopting a patch and are arranged on the built-in driving circuit board (1), the linear Hall sensors (2) are arranged on a circumference which takes the axial lead of the motor rotor (4) as the center of a circle, and the angle difference value of two adjacent linear Hall sensors (2) on the circumference is 90 degrees.

6. The mechanism of claim 1, wherein the mechanism comprises: the planar induction magnetic steel (3) is cylindrical, the planar induction magnetic steel (3) is a pair of polar magnetic steels, and the planar induction magnetic steel (3) is fixedly connected with a rotor shaft of the motor rotor (4).

7. The mechanism of claim 1, wherein the mechanism comprises: an angle difference exists between the N-pole magnetic field direction of the planar induction magnetic steel (3) and the N-pole magnetic field direction of the main magnetic field of the motor rotor.