KR101749522B1 - A device of Hall sensors installation position error correction for BLDC motors having linear Hall sensors and a method thereof - Google Patents

Abstract

The present invention relates to a stator having a rotor including a permanent magnet, a stator having a coil wound around the rotor to form a magnetic force, and a stator wound around the stator to generate an output signal A Hall sensor mounting position error correction apparatus of a BLDC motor including a linear Hall sensor, the apparatus comprising: a detection section for detecting output signals H ₁ , H ₂ and H ₃ output from the three linear Hall sensors; Converting the output signals H ₁ , H ₂ and H ₃ into orthogonal two-phase converted signals H _a and H _b and converting the converted signals H _a and H _b into normalized signals H _an and H _bn ; And a calculation unit for calculating a rotation angle of the motor from the normalized conversion signals H _an and H _bn output from the conversion unit, wherein the conversion unit converts the output signals H ₁ , H ₂ and H ₃ into two-phase conversion signals H converted to _{a, b} and H It is characterized in that is made by Clarke transformation (Clarke Transformation).

Description

FIELD OF THE INVENTION [0001] The present invention relates to a Hall sensor mounting position error correction apparatus and method for a BLDC motor having a linear Hall sensor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BLDC motor, and more particularly, to an apparatus and a method for correcting a mounting position error of a hall sensor in a case where a linear hall sensor is used to detect the position or rotational speed of the rotor in a BLDC motor .

A brushless direct current (BLDC) motor removes the brush of a conventional direct current (DC) motor. The brush has a permanent magnet. The permanent magnet is provided in the rotor. A magnetic force . Since such a BLDC motor has no mechanical friction involved in a motor structure including a conventional brush, it is capable of high-speed and high-efficiency driving, has no noise and vibration, and is excellent in durability. Because of these advantages, BLDC motors are widely applied to various electronic products, medical devices, military supplies, and aviation equipment.

The stator of the BLDC motor is usually wound with a three-phase coil, and a controlled current is supplied to each coil in a separate rectifying circuit. Since the current supplied to the three-phase coil must be controlled according to the position of the rotor, a hall sensor (Hall-Effect Sensor, also referred to as a Hall sensor) capable of detecting the position of the rotor is used together. 1, generally, in a BLDC motor 10, three Hall sensors h _A , h _B , and h _C are provided around a rotor R. Hall sensors h _A , h _B and h _C output signals of '0' (Low) and '1' (High) by a magnetic field which changes when the rotor R to which the permanent magnet is coupled rotates. When the signals detected from the three hall sensors h _A , h _B and h _C are sequentially referred to as ABC, six signals of, for example, 100, 110, 010, 011, 001 and 101 The signals are repeated and output in sequence. Since the three Hall sensors h _A , h _B , and h _C can not output 000 or 111 in the arrangement, the position of the rotor R can be detected in 60 ° (degrees) by the above six signals, Whereby the current supplied to the stator is controlled.

The hall sensors h _A , h _B , and h _C used in the above-described conventional BLDC motor 10 were latch type Hall sensors that output digital signals. When a latch type Hall sensor is used, there is no great problem in calculating the position or rotational speed of the rotor in the high-speed operation period. However, as described above, when the position of the rotor R is detected in units of 60 degrees Therefore, there is a problem in that it is difficult to accurately calculate the position and rotational speed of the rotor in the low-speed operation section.

In order to solve these problems, Song Chi-young, inventor of the present application, disclosed in Korean Patent Application No. 10-2008-0097732 (hereinafter referred to as " the 732 patent ") that " a brushless DC motor using a linear hall sensor, Method ". To describe in more detail with reference to the '732 patent, three linear Hall sensors installed in a BLDC motor have a sinusoidal output having a 120 ° (phase) phase difference. Converting the output of the three holes signal (h _A, h _B, h _C) into coordinate values on the two-dimensional plane, and the coordinate values on the A (x _1, y ₁₎ and the coordinate value on the B (x _2, y ₂₎ The displacement amount of the angle? Formed by the sum of P (x ₁ + x ₂ , y ₁ + y ₂ ) and the x axis can be expressed by the following equation (1).

, (

) 식(1)

, (

) Equation (1)

The displacement of the angle (θ) according to the above equation (1) represents the amount of displacement of the rotor, and the speed of the rotor can be calculated by calculating the rate of change with time. In addition, the '732 patent, as shown at _{P (x 1 + x 2,} y 1 + y 2) where, even if the second and fourth quadrant are the displacement and velocity of each (θ) can be calculated.

As described above, the method using the linear Hall sensor can accurately calculate the position and speed of the rotor compared with the conventional method using the latch type Hall sensor. Especially, it can be useful when the position and speed of the motor are required to be calculated in the low speed operation region.

On the other hand, a linear Hall sensor generally has an output voltage linearly proportional to the magnetic flux density (see FIG. 2), and the magnetic flux density applied to the linear Hall sensor is applied to the rotor And is inversely proportional to the effective air gap (EAG) between the permanent magnets (see FIG. 3). Therefore, when the conventional linear Hall sensor is used for a BLDC motor, there is a problem that the output voltage of the linear Hall sensor fluctuates greatly when there is an error in the mounting position of the linear Hall sensor. If further described in detail with reference to Figure 4, the three linear Hall sensors H1, H2, H3, respectively of the distance yirumyeonseo each other 120 ° standing treat the rotor center (degrees) away from the rotor d _1, d _2, d ₃ are preferably the same. The output signals H ₁ , H ₂ and H ₃ detected when the three linear Hall sensors H ₁ , H ₂ and H ₃ are installed in the correct positions are formed in the form of a sine wave having a phase difference of 120 ° (degrees) It is most ideal to appear. However, due to various factors that may occur in the motor manufacturing process, it is practically very difficult to install the linear Hall sensor in the correct position without error. In addition, as the mounting error of the linear Hall sensor is reduced, do.

However, if the mounting position of the linear Hall sensor is deviated in this manner, there arises a problem that the position and rotational speed of the motor can not be accurately measured.

Korean Patent Publication No. 10-2008-0097732

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and provides a device and method for correcting a position error of a Hall sensor mounted on a BLDC motor having a linear Hall sensor so that the position and speed of the motor can be accurately calculated even when there is an error in the Hall sensor mounting position .

It is another object of the present invention to provide an apparatus and method for correcting a position error of a hall sensor, which can precisely calculate the position and speed of a motor without physically changing the position of the hall sensor.

According to an aspect of the present invention, there is provided a stator comprising: a rotor including a permanent magnet; a stator having a coil wound around the rotor to form a magnetic force; 1. A Hall sensor mounting position error correction apparatus for a BLDC motor including three linear Hall sensors for generating a signal,

The three linear Hall respective output signals outputted from the sensor H _1, H _2, and a detection unit for detecting the H _3, detected by the detector output signal _{H 1, H 2, H 3} 2 converted signal H on the perpendicular to the converted to _a, H _b, and the rotation of the motor from the converted signal H _a, conversion unit, and a normalized transform signal H _an, H _bn outputted from the conversion unit for converting a H _b signals H _an, H _bn normalizes And an arithmetic unit for calculating an angle. The conversion unit converts the output signals H ₁ , H ₂ and H ₃ into orthogonal transform signals H _a and H _b orthogonal to each other by means of Clarke Transformation .

According to another aspect of the present invention, there is provided a stator comprising: a rotor including a permanent magnet; a stator having a coil wound around the rotor to form a magnetic force; A method for correcting a position error of a Hall sensor mounted on a BLDC motor, comprising the steps of:

A detection step of detecting each of the output signals H ₁ , H ₂ , and H ₃ output from the three linear hall sensors; and a detection step of detecting output signals H ₁ , H ₂ and H ₃ detected in the detection step, signal H _a, converted to a H _b, and the converted signal H _a, and a conversion step of converting a H _b signals H _an, H _bn normalize the motor from the normalized transform signal H _an, H _bn outputted from the conversion step And a calculating step of calculating a rotation angle of the rotor, wherein the converting step is performed by Clarke Transformation.

According to the apparatus and method for correcting a position error of a hall sensor, it is possible to accurately calculate a rotation angle and a rotation speed of the motor even if there is an error in the hall sensor mounting position.

In addition, by utilizing the apparatus and method for correcting a position error of a hall sensor according to the present invention, it is possible to accurately calculate the rotation angle of the motor without physically correcting the error in the mounting position of the hall sensor, There is an effect that can be done.

1 is a schematic view showing a structure of a general BLDC motor.
2 is a graph showing a relationship between a magnetic flux density applied to the Hall sensor and an output voltage of the Hall sensor.
3 is a graph showing the relationship between the distance (EAG) from the hall sensor to the permanent magnet and the magnetic flux density of the permanent magnet on the Hall sensor accordingly.
4 is a diagram showing the arrangement relationship between a rotor and a Hall sensor in a BLDC motor;
5 is a graph showing an output signal of the Hall sensor in the BLDC motor of Fig.
6 is a view showing an apparatus for correcting a position error of a Hall sensor mounted on a BLDC motor having a linear Hall sensor according to a preferred embodiment of the present invention.
7 is a graph showing the waveform of an output signal detected by the detection unit of the hall sensor mounting position error correction apparatus of FIG.
8 is a graph showing a waveform of a normalized converted signal output from the converting unit of the Hall sensor mounting position error correction apparatus of FIG.
9 is a flowchart showing a Hall sensor mounting position error correction method of a BLDC motor having a linear Hall sensor according to a preferred embodiment of the present invention.
10 is a graph showing a test result obtained by detecting a rotation angle of a motor by using an apparatus and method for correcting a position error of a hall sensor according to the present invention in detecting a rotational angle of a BLDC motor having a linear hall sensor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus and method for correcting a position error of a Hall sensor of a BLDC motor having a linear Hall sensor according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. The following embodiments provide exemplary explanations for implementing the technical idea of the present invention, and the scope of the present invention should not be construed as being limited to such embodiments. The scope of the present invention is to be interpreted broadly in accordance with the description in the claims.

Throughout this specification, "position of motor" refers precisely to "position of motor rotor. &Quot; Also, "motor speed" refers to exactly "motor rotor speed". The term "position" means a rotation angle of the motor rotor from the reference point, and "rotation angle" or "displacement amount" The term "speed" means a rate of change of the motor position with respect to time, and "rotational speed"

Further, the "Hall sensor mounting position error correction device of a BLDC motor having a linear Hall sensor" of the present invention is abbreviated as "Hall sensor mounting position error correction device". Further, the "Hall sensor mounting position error correction method of a BLDC motor having a linear Hall sensor" of the present invention is abbreviated as "Hall sensor mounting position error correction method".

6, an apparatus for correcting a Hall sensor mounting position error of a BLDC motor having a linear Hall sensor according to the present invention includes a linear Hall sensor for detecting an output signal from three linear Hall sensors installed in a BLDC motor (hereinafter also referred to as a " And a detection unit 110 for detecting the detection signal. The output signal detected through the detection unit 110 is, for example, as shown in FIG. The distances d ₁ , d ₂ and d ₃ between the permanent magnet of the motor stator and each hall sensor can not be completely equal due to the influence of the mounting position error of the linear Hall sensors H 1, H 2 and H ₃ , but are slightly different. Therefore, the signals H ₁ , H ₂ , and H ₃ output from the hall sensors have different amplitudes from those of the ideal case shown in FIG. In this embodiment, as shown in FIG. 7, the amplitude of H ₁ is the largest, H ₂ is the smallest, and H ₃ is the medium size.

In order to calculate the rotation angle of the motor rotor using these three output signals H ₁ , H ₂ , and H ₃ , a method of normalizing the maximum and minimum values of the signals H ₁ , H ₂ , and H ₃ may be considered . However, in order to do this, since the output signal of each moment must be measured while rotating the rotor more than one turn, the calculation amount of the controller increases and the maximum value and / or the minimum value is deformed to a specific value due to the influence of noise (singular value) There may arise a problem that Therefore, the Applicant intends to propose a more stable method. It converts signals detected by three linear Hall sensors into a two-phase rotation domain and analyzes them. Clarke Transformation (also known as Alpha-beta Transformation) is useful for transforming and interpreting three-phase circuits into an orthogonal two-phase rotating domain. . The Applicant proposes a method of using this clock conversion to detect the rotation angle of a BLDC motor having a linear Hall sensor.

To this end, the Hall sensor mounting position error correction apparatus of the present invention corrects the signals H ₁ , H ₂ , and H ₃ detected by the detecting unit by using _a sine wave of H _a (sine wave) and H _b (cosine wave) And a conversion unit 120 for converting the input data into a digital signal. More specifically, the conversion unit 120 converts H ₁ , H ₂ , and H ₃ into H _a and H _b by the following equations (2) and (3).

식(2)

Equation (2)

식(3)

Equation (3)

The waveforms of the signals indicated by the converted signals H _a and H _b are shown in FIG. That is, H _a and H _b are represented by a sine wave and a cosine wave having a phase difference of 90 ° (degrees). Thus, when H _a is passed to 0 (zero), H _b is passed as a maximum or minimum value has a, H _b is 0 (zero) H has _a maximum or minimum values. That is, H _a that detects a H _b from the point 0 (zero) if the amount of the maximum value, if a negative value is the minimum value, H _b is to detect the H _a at the point 0 (zero) the amount of If it is a value, it is a maximum value. If it is a negative value, it is a minimum value. Each of H _a and H _b can be normalized to H _an and H _bn using the detected maximum and minimum values.

On the other hand, when the difference between the amplitudes of the signals H ₁ , H ₂ and H ₃ output from the hall sensor is large, that is, when the distances d ₁ , d ₂ and d ₃ between the permanent magnets of the stator and the Hall sensors are large The phase difference between H _a and H _b may deviate from 90 degrees (degrees). In such a case, it may be desirable to physically correct the mounting position of the hall sensor, rather than applying the apparatus and method for correcting the position error of the hall sensor according to the present invention. However, when the mounting position of the Hall sensor is within a certain error range, that is, when the difference between d ₁ , d ₂ and d ₃ is not large, the phase difference between H _a and H _b is not largely deviated from 90 ° The apparatus and method for correcting the position error of the Hall sensor according to the invention can be more effectively utilized in such a case.

The normalized conversion signal H _an And H _bn can be used to calculate the rotational angle and rotational speed of the motor. Hall sensor mounting position error correcting device of the present invention To this end, the normalized conversion signal output from the conversion unit (120) _an H And an operation unit 130 for calculating a rotation angle and a rotation speed of the motor using H _bn .

The calculation unit 130 calculates the rotation angle and the rotation speed of the motor by the method described in the aforementioned '732 patent. More specifically, the normalized converted signal H _an And H _bn a two-dimensional coordinate values of the converted H _an the plane to the coordinate values (x1, y1) to the sum of the calculated coordinate values (x2, y2) of the H _bn and, H _an the H _bn P (x1 + x2, y1 + y2) with the X axis is calculated according to the above-described method. The amount of displacement of the angle? Represents the rotation angle of the motor. Further, the rotation speed of the motor can be calculated by calculating the rate of change of the calculated amount of displacement with respect to time.

Alternatively, the calculating unit 130 may calculate the rotation angle or speed of the motor using only one of the coordinate values (x1, y1) of H _{an or} the coordinate values (x 2, y 2) of H _bn . That is, the sum of _an H and _{H bn P (x1 + x2,} y1 + y2) , instead, any one of _an H, or a H _bn may calculate the amount of displacement of each forming with the X-axis as a rotation angle of the motor. However, to increase the accuracy of motor rotation angle and speed calculation, it is desirable to use the sum P (x1 + x2, y1 + y2) of H _an and H _bn .

The rotation angle and speed of the motor calculated by the calculation unit 130 are transmitted to the control unit 140 for controlling the motor drive and the control unit 140 receives the rotation angle information of the motor and outputs the current supplied to the coil wound on the stator .

Next, a Hall sensor mounting position error correction method using the Hall sensor mounting position error correction apparatus described above with reference to FIG. 9 will be described. The method for correcting the position error of the Hall sensor according to the present invention is characterized in that the detecting unit 110 detects the output signals H ₁ , H ₂ and H ₃ from the three linear Hall sensors H ₁ , H ₂ and H ₃ installed in the motor . The detected output signals H ₁ , H ₂ , and H ₃ have three sinusoidal waveforms, and the waveforms of the output signals H ₁ , H ₂ , and H ₃ may have different amplitudes from each other.

Next, a conversion step (S120) of performing Clarke Transformation (Clarke Transformation) and normalizing the output signals H ₁ , H ₂ and H ₃ detected in the detection step (S110) is performed by the conversion unit 120. In the conversion step S120, the output signals H ₁ , H ₂ , and H ₃ detected in the detection step S110 are converted into H _a and H _{b which} are sinusoidal waves having a phase difference of 90 ° (degrees) _an and H _bn . The relationship between the output signals H ₁ , H ₂ , and H ₃ and the converted signals H _a and H _b is as shown in the above-mentioned equations (2) and (3).

Next, _an operation step (S130) of calculating the rotation angle and rotation speed of the motor by using the conversion signals H _an and H _bn normalized by the operation unit 130 is performed. In the calculation step (S130) the coordinate values _{H an (x1, y1),} H bn (x2, y2), or the sum of P (x1 + x2, y1 + y2) converting the H _an, H _bn as a two-dimensional plane The rotation angle and the rotation speed of the motor can be calculated using the amount of displacement of the angle &thetas;

Next, a control step (S140) of controlling the current supplied to the motor by using the rotation angle and speed information of the motor calculated in the calculation step (S130) is performed by the control unit (140). In the control step S140, the current supplied to each coil of the stator is controlled according to the position of the motor rotor.

FIG. 10 is a graph showing a test result of detecting a rotation angle of a motor by using an apparatus and method for correcting a position error of a hall sensor according to the present invention. This test is to calculate the rotation angle of the motor while rotating the motor at a constant speed. 10A shows the result of calculating the rotation angle of the motor using the output signals H ₁ , H ₂ and H ₃ of the Hall sensors H ₁ , H ₂ and H ₃ . The rotation angle (Y axis) of the motor with respect to time (X axis) is shown. The rotational angle of the motor does not increase linearly but increases unevenly due to the mounting position error of the linear Hall sensor. When the rotation angle of the motor is calculated using the apparatus and method for correcting the position error of the hall sensor according to the present invention under the same test conditions, that is, the normalization obtained by converting the Hall sensor output signals H ₁ , H ₂ and H ₃ into H _an and H _bn And the rotation angle of the motor is calculated as shown in FIG. 10 (b). It can be confirmed that the rotational speed of the motor is more linearly increased as compared with FIG. 10 (a). That is, it is confirmed that the accuracy of calculating the rotation angle of the motor is improved.

Although the above description has been made with reference to a 2-pole motor, the present invention can also be applied to a 4-pole, 6-pole, 8-pole, Can be utilized in a similar manner.

According to the apparatus and method for correcting a position error of a hall sensor according to the present invention, it is possible to accurately calculate the rotation angle and the rotation speed of the motor even if there is a slight error, have. By using the apparatus and method for correcting a position error of a hall sensor according to the present invention, it is not necessary to physically correct an error in a mounting position of the hall sensor, so that the productivity of the motor can be increased and the production cost can be reduced.

110:
120:
130:
140:
S110: Detection step
S120: conversion step
S130: operation step
S140: control step

Claims (7)

delete delete delete A stator comprising a rotor including permanent magnets, a stator having a coil wound around the rotor to form a magnetic force, three linear Hall sensors installed on the outer circumference of the rotor to generate an output signal by a Hall effect Wherein the Hall sensor mounting position error correction device of the BLDC motor comprises:
A detector for detecting output signals H ₁ , H ₂ , and H ₃ output from the three linear Hall sensors;
The converting the output signal H _1, H _2, H ₃ detected by the detecting unit 2 converts the signal H _a, H _b on the perpendicular by the clock conversion (Clarke Transformation), and the converted signal H _a, normalize H _b signal H _an and H _bn ,
Converting the normalized transform signal H _an, H _bn outputted from the conversion section into a two-dimensional plane coordinates _{H an (x1, y1),} H bn (x2, y2) the sum P (x1 + x2 of, y1 + and an arithmetic unit for calculating a rotation angle of the motor by using a displacement amount of an angle (?) formed by the yaw axis (y2) and the X axis. delete delete A stator comprising a rotor including permanent magnets, a stator having a coil wound around the rotor to form a magnetic force, three linear Hall sensors installed on the outer circumference of the rotor to generate an output signal by a Hall effect The method comprising the steps of:
A detection step of detecting respective output signals H ₁ , H ₂ , and H ₃ output from the three linear hall sensors,
The output signals H ₁ , H ₂ , and H ₃ detected in the detecting step are expressed by the following equations

,

And a conversion step of converting a second conversion signal H _a, H _b on the perpendicular, and converting the converted signal H _a, H _b H signal _{an, bn} H normalize by,
Converting the normalized transform signal H _an, H _bn outputted from the conversion step to a two-dimensional plane coordinates _{H an (x1, y1),} H bn (x2, y2) the sum P (x1 + x2 of, y1 + and calculating an angle of rotation of the motor by using a displacement amount of an angle (?) formed by the y-axis and the y-axis with the X-axis.

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