KR102502932B1 - Device for determining the rotor position using 3 linear hall sensor and method thereof - Google Patents

Abstract

The present invention relates to an apparatus and method for detecting a rotor position of a brushless motor. An apparatus for detecting a rotor position according to an embodiment of the present invention is a dipole magnetized magnet positioned at one end of a shaft, positioned away from the magnet by a predetermined distance, and measuring the strength of a magnetic field emitted from the magnet. A first linear hall sensor for sensing, positioned away from the magnet by a predetermined distance, and a second linear hall sensor for sensing the strength of the magnetic field emitted from the magnet, positioned at a distance from the magnet and a third linear Hall sensor for detecting the strength of the magnetic field emitted from the magnet and output values of the first linear Hall sensor, the second linear Hall sensor, and the third linear Hall sensor are obtained, and the obtained output values are corrected for detection. It may include a rotor position determination unit for determining the position of the rotor based on the value.

Description

Rotor position detection device and method using 3 linear hall sensors {Device for determining the rotor position using 3 linear hall sensor and method thereof}

One embodiment of the present invention relates to a device and method for detecting the position of a rotor using three linear Hall sensors.

A brushless motor is a motor in which mechanical contacts such as a brush and a commutator are eliminated and implemented as an electronic commutator. Brushless motors have windings wound only on the stator, and strong permanent magnets are installed on the rotor. The rotor rotates when the electromagnetic commutation mechanism supplies current to the stator coil based on the rotation angle.

The electronic commutation mechanism controls the ability to energize or de-energize the individual stator coils. The electronic commutation mechanism receives rotor position information from the rotor position sensor, and supplies or blocks commutation to a corresponding coil of the stator based on this. For precise position control of a brushless motor, it is necessary to detect the precise position of the rotor.

Recently, ISO 2626, an international standard for vehicle functional safety to prevent accidents due to errors in electrical and electronic systems installed in vehicles, has been enacted by ISO. ISO 2626 is a risk-based safety standard that quantitatively calculates the risk of detrimental operating situations, defines safety measures to avoid or control systematic failures, and to detect or control or mitigate the effects of random hardware failures.

With the prevalence of hybrid vehicles or electric vehicles, brushless motors are installed in vehicles, and the need for brushless motors to comply with ISO 26262 has also emerged. In order to comply with ISO 26262, the failure of the rotor position sensor of a brushless motor must be detected.

Therefore, it is required to provide a technology capable of accurately detecting the position of a rotor in a brushless motor and determining whether a position sensor is out of order.

Japanese Patent Laid-Open No. 2008-109773

A technical problem to be solved by an embodiment of the present invention is to provide an apparatus and method for detecting a rotor position of a brushless motor.

Another technical problem to be solved by an embodiment of the present invention is to provide a device and method capable of determining whether an abnormality has occurred in a rotor position sensor of a brushless motor.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

A rotor position detection device according to an aspect of the present invention for achieving the above technical problem is a dipole magnetized magnet positioned at one end of a shaft, positioned away from the magnet by a predetermined distance, and from the magnet A first linear hall sensor for detecting the intensity of the emitted magnetic field, a second linear hall sensor located at a predetermined distance from the magnet and detecting the intensity of the magnetic field emitted from the magnet, A third linear Hall sensor positioned apart from a predetermined distance and detecting the strength of a magnetic field emitted from the magnet and output values of the first linear Hall sensor, the second linear Hall sensor, and the third linear Hall sensor are obtained, and the acquisition is performed. It may include a rotor position determination unit for determining the position of the rotor based on the detected value obtained by correcting the output value.

According to one embodiment of the present invention as described above, it is possible to detect the rotor position of the brushless motor and also determine whether or not the rotor position sensor has an abnormality.

1 is a cross-sectional view of a brushless motor according to an embodiment of the present invention.
2 and 3 are diagrams illustrating positions of a magnet and a linear Hall sensor according to an embodiment of the present invention.
4 is a graph showing output values of a linear Hall sensor according to an embodiment of the present invention.
5 is a graph illustrating detection values obtained by correcting an output value of a linear Hall sensor according to an embodiment of the present invention.
6 is a flowchart illustrating a method for detecting a rotor position according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present invention complete, and the common knowledge in the art to which the present invention belongs It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

1 is a cross-sectional view of a brushless motor according to an embodiment of the present invention.

Referring to FIG. 1 , a brushless motor 100 according to an embodiment of the present invention includes a stator 110, a rotor 120, a shaft 130, a magnet 140, and a linear hall sensor. (linear hall-sensor, 150) and a sensor circuit board 170.

The stator 110 is provided with a wire through which current flows, and magnetic force is generated when current flows through the wire. The rotor 120 is provided with magnets magnetized with a plurality of poles. The magnetic force generated in the stator 110 applies force to the magnet of the rotor 120, and the shaft 130 connected to the rotor 120 rotates.

The shaft 130 is a rotation center axis of the brushless motor 100 . When current flows through the stator 110, the rotor 120 rotates due to magnetic force, and the shaft 130 to which the rotor 120 is attached also rotates.

The magnet 140 according to an embodiment of the present invention may be located at one end of the shaft 130 . The magnet 140 may be a single-sided dipole magnetized magnet having one N pole and one S pole attached thereto. The magnet 140 may be a disk-shaped circular magnet or a donut-shaped ring-shaped magnet. The magnet 140 is an end shaft type attached to one end of the shaft 130 inside the brushless motor 100, or a through shaft type fitted to one end of the shaft 130. can be

The sensor circuit board 170 is a circuit board on which the linear Hall sensor 150 is located. The sensor circuit board 170 may be located on the bottom surface of the brushless motor 100, but this is only an example and is not limited thereto. The sensor circuit board 170 may supply power to the linear hall sensor 150 or provide a connection between the linear hall sensor 150 and an external electric/electronic device.

The linear Hall sensor 150 may detect a magnetic field emitted from the magnet 140 . The linear hall sensor 150 may output a detection value proportional to the strength of the sensed magnetic field. The detection value may be voltage or current. When the magnet 140 rotates along with the rotation of the shaft 130, the strength of the magnetic field applied to the linear hall sensor 150 around the magnet 140 changes according to the rotation. The linear Hall sensor 150 may detect a change in the magnetic field and output a detection value according to the magnitude.

According to an embodiment of the present invention, the linear hall sensor 150 may include a first linear hall sensor 152, a second linear hall sensor 154, and a third linear hall sensor 156. The first linear Hall sensor 152 may output a first output value, the second linear Hall sensor 154 may output a second output value, and the third linear Hall sensor 156 may output a third output value.

Referring to FIG. 1 , an apparatus for detecting a rotor position according to an embodiment of the present invention may include a magnet 140, a linear Hall sensor 150, and a rotor position determining unit.

Although the rotor position determining unit is not shown in FIG. 1 , it may be included in the sensor circuit board 170 or provided outside the brushless motor 100 , but this is only an example and is not limited thereto.

The brushless motor 100 shown in FIG. 1 may be a brushless motor including a rotor position detection device according to an embodiment of the present invention.

2 and 3 are diagrams illustrating positions of a magnet and a linear Hall sensor according to an embodiment of the present invention.

Referring to FIGS. 2 and 3 , arrangement positions of the magnet 140 and the linear Hall sensor 150 according to an embodiment of the present invention will be described in detail.

As shown in FIG. 2, the magnet 140 may be of the end shaft type attached to the end of the shaft 130, but according to another embodiment, a through through the shaft 130 and fitted to the end of the shaft 130. It may be a shaft type.

The magnet 140 and the shaft 130 may share the same central axis 210 . The linear hall sensor 150 may be positioned on a virtual plane parallel to a cross section of the magnet 140 orthogonal to the central axis 210 and separated from the magnet 140 by a predetermined distance. The imaginary plane may be the sensor circuit board 170 , and the sensor circuit board 170 may be spaced apart from the magnet 140 by a predetermined distance.

The linear hall sensor 150 may be located inside the projection 220 in which the magnet 140 is projected onto the sensor circuit board 170 . As shown in FIG. 2, when the radius of the magnet 140 is r and the distance between the central axis 210 and the linear Hall sensor 150 is d, d and r may satisfy the condition d<r. there is.

3 is a bottom view looking at the magnet 140 from the bottom of the brushless motor 100 .

As shown in FIG. 3 , the linear hall sensor 150 may be located inside the region of the magnet 140 . The first linear hall sensor 152, the second linear hall sensor 154, and the third linear hall sensor 156 included in the linear hall sensor 150 may be located on the same radius from the central axis 210. there is.

The first linear Hall sensor 152 and the third linear Hall sensor 156 may form an angle of 90 degrees with respect to the central axis 210 . Based on the first linear hall sensor 152, the third linear hall sensor 156 may be located at a 90 degree point in a clockwise or counterclockwise direction on the same radius.

The second linear hall sensor 154 may be located between the first linear hall sensor 152 and the third linear hall sensor 156 on the same radius. The second linear hall sensor 154 may be located at a point forming an acute angle with the first linear hall sensor 152 on the radius. The size of the acute angle is Φ, and the Φ may be a value larger than 0 degree and smaller than 90 degrees.

4 is a graph showing output values of a linear Hall sensor according to an embodiment of the present invention.

Referring to FIG. 4 , the first output value 410 of the first linear hall sensor 152, the second output value 420 of the second linear hall sensor 154, and the third output value of the third linear hall sensor 156 430 may have different gains, offsets, and phases.

The graph of FIG. 4 is illustrative, and not limited thereto.

5 is a graph illustrating detection values obtained by correcting an output value of a linear Hall sensor according to an embodiment of the present invention.

As shown in FIG. 4, since the first output value 410, the second output value 420, and the third output value 430 have different gains, offsets, and phases, raw values cannot be used as they are.

Accordingly, according to an embodiment of the present invention, the rotor position determiner may correct the gain, offset, and phase of the first output value 410, the second output value 420, and the third output value 430. A first detection value 510 obtained by correcting the first output value 410, a second detection value 520 obtained by correcting the second output value 420, and a third detection value 530 obtained by correcting the third output value 430 This is shown in Figure 5.

6 is a flowchart illustrating a method for detecting a rotor position according to an embodiment of the present invention.

Referring to FIG. 6, a method for detecting a rotor position according to an embodiment of the present invention will be described in detail.

The rotor position detector obtains the first output value of the first linear hall sensor 152, the second output value of the second linear hall sensor 154, and the third output value of the third linear hall sensor 156 (S110).

The rotor position detector corrects the first output value, the second output value, and the third output value to derive V1, V2, and V3, respectively (S120).

The rotor position detection unit derives the first position value θ1, the second position value θ2, and the third position value θ3 using the following formula (S130). The rotor position detector uses Φ, which is an angle formed between the V1, V2, and V3 and the first linear Hall sensor 152 and the second linear Hall sensor 154, to derive the θ1, θ2, and θ3.

The rotor position detection unit determines whether a difference in magnitude between the first position value and the second position value is within a predetermined detection error α (S140).

If the rotor position detection unit is within the detection error as a result of the determination in step S140, it determines whether or not the size difference between the first position value and the third position value is within the detection error (S150).

If the rotor position detection unit is within the detection error as a result of the determination in step S150, it is determined that the linear hall sensor 150 is normally operating and the first position value indicates the position of the rotor 120 (S155). .

If the rotor position detection unit is not within the detection error as a result of the determination in step S150, it determines whether a difference between the second position value and the third position value is within the detection error (S170).

If the rotor position detector is within the detection error as a result of the determination in step S170, it is determined that an abnormality has occurred in the third linear hall sensor 156 and the second position value indicates the position of the rotor 120 (S175 ).

If the rotor position detection unit is not within the detection error as a result of the determination in step S140, it determines whether the first position value is within the detection error range of the third position value (S160).

If the rotor position detection unit is within the detection error as a result of the determination in step S160, it determines whether the second position value is within the detection error range of the third position value (S180).

If the rotor position detector is within the detection error as a result of the determination in step S180, it is determined that an abnormality has occurred in the first linear hall sensor 152 and the third position value indicates the position of the rotor 120 (S185 ).

The rotor position detection unit determines that an abnormality has occurred in the linear hall sensor 150 and determines that the position of the rotor 120 cannot be detected if the determination results of the steps S160, S170 and S180 are all within the detection error range. (S190).

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. you will be able to understand Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

brushless motor 100
stator 110
rotor 120
shaft 130
magnet 140
Linear Hall Sensor 150
First linear hall sensor 152
Second linear hall sensor 154
3rd linear hall sensor 156
sensor circuit board 170

Claims (7)

A dipole magnetized magnet positioned at one end of the shaft;
a first linear hall sensor positioned away from the magnet by a predetermined distance and sensing the intensity of a magnetic field emitted from the magnet;
a second linear hall sensor positioned away from the magnet by a predetermined distance and detecting the intensity of a magnetic field emitted from the magnet;
a third linear hall sensor located at a predetermined distance from the magnet and sensing the intensity of a magnetic field emitted from the magnet; and
A rotor position determining unit for obtaining output values of the first linear Hall sensor, the second linear Hall sensor, and the third linear Hall sensor and determining the position of the rotor based on a detection value obtained by correcting the obtained output values; ,
The first linear hall sensor,
Outputting a first output value by detecting the magnetic field strength of the magnet;
The second linear hall sensor,
Outputting a second output value by detecting the magnetic field strength of the magnet;
The third linear hall sensor,
Outputting a third output value by detecting the magnetic field strength of the magnet;
The rotor position determining unit,
The first detection value, the second detection value, and the third detection value obtained by obtaining the first output value, the second output value, and the third output value and correcting the gain, offset, and phase, respectively. Deriving a value, determining whether or not the rotor is abnormal and the position of the rotor based on the derived first detection value, second detection value, and third detection value,
Rotor position detection device. According to claim 1,
The magnet,
Including a ring-shaped or circular dipole single-sided magnetized magnet,
Including end shaft type or through shaft type,
Rotor position detection device. According to claim 1,
The first linear hall sensor, the second linear hall sensor, and the third linear hall sensor,
Located on a cross section orthogonal to the central axis of the magnet and a parallel imaginary plane spaced apart at a predetermined distance,
It is located on a radius of the same distance from the center point where the central axis and the virtual plane meet,
The first linear Hall sensor and the third linear Hall sensor form an angle of 90 degrees,
The second linear hall sensor is located between the first linear hall sensor and the third linear hall sensor,
Rotor position detection device. delete According to claim 1,
The rotor position determination unit,
A first position value is derived based on the first detection value and the third detection value;
A second position value is derived based on the first detection value and the second detection value;
A third position value is derived based on the second detection value and the third detection value;
If the first position value and the second position value are within a predetermined detection error, and the first position value and the third position value are within the detection error, it is determined that the sensor is operating normally, and the first position value is It is judged by indicating the rotor position,
If the first position value and the second position value are within a predetermined detection error, and the first position value and the third position value are not within the detection error, the second position value and the third position value are detected. It is additionally determined whether or not it is within the error, and as a result of the additional determination, if it is within the detection error, it is determined that an error has occurred in the third linear hall sensor, and it is determined that the second position value indicates the rotor position, and as a result of the additional determination, the detection error If it is not within the range, it is judged as a sensor error.
The first position value and the second position value are not within the detection error, the first position value and the third position value are within the detection error, and the second position value and the third position value are within the detection error. If it is within the error, it is determined that an abnormality has occurred in the first linear hall sensor, and it is determined that the third position value indicates the rotor position,
The first position value and the second position value are not within the detection error, the first position value and the third position value are not within the detection error, or the second position value and the third position value are not within the detection error. If it is not within the detection error, it is determined that a sensor error occurs,
Rotor position detection device. According to claim 5,
The first position value is,
An arctangent value of a value calculated by dividing the first detection value by the third detection value,
The second position value θ2 is a value that satisfies the following formula,

The third position value θ3 is a value that satisfies the following formula,

Rotor position detection device.
Here, Φ is an angle formed between the first linear hall sensor and the second linear hall sensor, V1 is the first output value of the first linear hall sensor, V2 is the second output value of the second linear hall sensor, and V3 is the second output value of the first linear hall sensor. 3 This is the third output value of the linear hall sensor. obtaining a first output value from a first linear hall sensor, a second output value from a second linear hall sensor, and a third output value from a third linear hall sensor;
deriving a first detection value obtained by correcting the first output value, a second detection value obtained by correcting the second output value, and a third detection value obtained by correcting the third output value;
deriving a first position value based on the first detection value and the third detection value;
deriving a second position value based on the first detection value and the second detection value;
deriving a third position value based on the second detection value and the third detection value;
Determining whether a size difference between the first position value and the second position value is within a predetermined detection error (first step);
If a result of the first step is within the detection error, determining whether a size difference between the first position value and the third position value is within the detection error (step 2);
If the result of the second step is within the detection error, determining that the operation is normal and that the first position value indicates the rotor position;
if the result of the second step is not within the detection error, determining whether a difference between the second position value and the third position value is within the detection error (third step);
determining that an abnormality has occurred in the third linear hall sensor and determining that the second position value indicates the position of the rotor when the result of the third step is within the detection error;
If the result is not within the detection error, determining that a sensor error has occurred and determining that the rotor position detection has failed;
if it is not within the detection error as a result of the first step, determining whether the first position value is within the detection error and the third position value (fourth step);
If the result of the fourth step is within the detection error, determining whether the second position value is within the detection error and the third position value (fifth step);
determining that an abnormality has occurred in the first linear Hall sensor and determining that the third position value indicates the rotor position when the result of the fifth step is within the detection error; and
If all of the results of the third step, the fourth step, and the fifth step are not within the detection error, determining that a sensor error has occurred and determining that the rotor position detection has failed; Including,
Rotor position detection method.

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