JP2003004486A - Device for detecting angle of rotation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for detecting the angle of rotation, capable of rapidly determining malfunctions. SOLUTION: The device for detecting the angle of rotation detects the location of the angle of rotation of a disk 10, by combining the output signals from on off two-level latch-type Hall elements 11A-11C arranged at regular intervals on the circular circumference of a rotator (disk 10). Sub-Hall element 12A-12C are arranged at the same angular locations as the Hall elements 11A-11C of each phase. By comparing the output signals of the Hall elements 11A-11C at the same angular locations with those of the sub-Hall elements 12A-12C, malfunctions in the Hall elements 11A-11C are detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device for detecting a rotation position angle of a rotating body such as an electric motor by means of hall elements arranged at an angle of 120 degrees, and in particular, it is possible to quickly discriminate a failure of the hall element. The present invention relates to a rotation angle detection device that can be used.

[0002]

2. Description of the Related Art A rotation angle detecting device using a Hall element of this type is used as a rotation angle detecting device for detecting the rotational position of a rotating body such as a brushless electric motor which moves a winding with an arbitrary voltage waveform from an inverter device. Some of them have been adopted and are described in, for example, Japanese Patent Laid-Open No. 9-74790.

This is because a hall element is arranged at an angle of 120 degrees around the rotor, and based on a rotation position signal indicating the rotation position of the rotor obtained by the hall element, a time interval of the rotation position signal is obtained at a resolution of every 60 degrees. Is measured, and the rotation angle is interpolated based on this time interval to create an estimated rotation angle,
The current or the voltage to be applied to the stator winding is calculated based on the estimated rotation angle.

Therefore, even if the angular interval of the rotational position signals is large, the angle information between the rotational position signals can be supplemented by interpolation calculation, and the rotational position signal generator can be simplified while maintaining the detection accuracy. There is a feature that the number of calculations can be further reduced to reduce the calculation load.

Another feature is that the larger the signal detection phase width, the smaller the influence of the error due to the variation in the detection time of the rotational position signal.

[0006]

By the way, when the failure detection of the above-mentioned conventional rotation angle detecting device is carried out based on the combination of the output signals of the Hall elements, the outputs of the three Hall elements are at the same level (whichever is the case). Also becomes a high level or a low level), it is possible to determine a failure.

That is, when one phase of the Hall element fails and the signal sticks to high level or low level,
When a combination of signals that does not occur under normal conditions (all signals are high level or all signals are low level), it can be determined that the detection device has failed.

However, such a failure detection method has a problem that it is necessary to rotate the rotor at an angle of 300 degrees or more at the maximum from the occurrence of the failure to the failure determination, and the failure determination cannot be performed promptly.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a rotation angle detecting device capable of promptly determining a failure.

[0010]

SUMMARY OF THE INVENTION A first aspect of the present invention is to provide a rotating body by combining output signals from ON / OFF two-level latch type Hall elements arranged at equal intervals on the circumference of the rotating body. In the rotation angle detection device that detects the rotation angle position of the sub hall element, the sub hall element is arranged at the same angle position as the hall element of each phase, and the hall signal at the same angle position is compared with the sub hall element to compare The feature is that a failure of the element is detected.

A second invention is characterized in that, in the first invention, the sub-hall element is a magnetic flux proportional element in which an output signal continuously changes in proportion to a magnetic flux.

In a third aspect based on the first aspect, the sub Hall element outputs an ON signal in an angular range smaller than that of the Hall element, and an intermediate level signal lower than the ON signal outside the angular range of the ON signal. Of the Hall element of the three-level latch type that outputs an OFF signal other than these, and the angle range for outputting the ON signal and the intermediate level signal is formed to be larger than the angle range of the ON signal of the Hall element. It is characterized by

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the determination of the failure of the hall element is made when the difference between the output of the hall element signal and the sub-hall element signal exceeds a predetermined value. It is characterized by

[0014]

According to the first aspect of the invention, therefore, the sub-Hall element is arranged at the same angular position as each Hall element, and the output signals of the Hall element and the sub-Hall element at the same angular position are compared to determine the Hall element In order to detect a failure, the output signals of both Hall elements are constantly compared to determine an abnormal state, and rapid failure determination can be performed. This failure determination is possible even when the rotor such as the rotor is stopped.

In the second invention, in addition to the effect of the first invention, since the sub Hall element is a magnetic flux proportional element in which the output signal continuously changes in proportion to the magnetic flux, signal inversion is gentle and the Hall Even if the mounting positions of the element and the sub Hall element are deviated, the deviation of both signals near the signal reversal position of the Hall element can be reduced, and erroneous detection prevention becomes easy.

In the third invention, in addition to the effect of the first invention, the sub Hall element outputs an ON signal in an angle range smaller than that of the Hall element, and outside the angle range of the ON signal, an intermediate signal lower than the ON signal is output. Outputs a level signal,
In addition to the above, the Hall element is a three-level latch type that outputs an OFF signal, and the angle range for outputting the ON signal and the intermediate level signal is formed to be larger than the ON signal angular range of the Hall element. The output signal of the sub Hall element near the inversion position becomes an intermediate level signal,
Even if the mounting positions of the hall element and the sub-hall element are deviated from each other, the deviation of both signals in the vicinity of the signal inversion position of the hall element can be reduced, and erroneous detection can be prevented easily.

In addition to the effects of the second or third aspect of the invention, in the fourth aspect of the invention, when the difference in signal output between the hall element and the sub-hall element exceeds a predetermined value, it is determined that there is a failure.
Failure determination can be performed without phase transition, and erroneous determination does not occur near the signal inversion position.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of a motor control system of a brushless motor using the rotation angle detection device to which the present invention is applied as a rotor phase detector. This motor control system is a stator coil (not shown) of the electric motor 1. And a phase detector 3 for detecting the rotation phase of a rotor (not shown) of the electric motor 1 and inputting it to the motor control unit 2.

The phase detector 3 as the rotation angle detector is magnetized so as to have a magnetic pole similar to the rotor magnetic pole of the electric motor 1, and is a disc 10 as a rotating body which rotates integrally with the rotor. First to third main hall elements 11A to 11C (sometimes referred to as hall elements) arranged around the U-phase winding of the electric motor 1 as the origin at every rotation angle of 120 degrees, and these first to third main hall elements 11A to 11C. The main hall elements 11A to 11C and the first to third sub hall elements 12A to 12C arranged at the same angular positions are provided.

First to third main hall elements 11A to 11C
Is as shown in FIGS. 2 (A), 2 (C) and 2 (E) according to the rotational position of the magnetic pole of the disk 10 that rotates with the rotor (displayed as an angle with the U-phase winding of the electric motor as the origin). on·
An output signal that is turned off is emitted, and by combining these output signals, the main hall elements 11A to 11C are set at every 60 degrees.
The combination of the output signals is different, and the rotation angles of the rotor and the disk 10 can be detected with a resolution of 60 degrees.

For example, now, the first main hall element 11A
Is an ON signal, the second main hall element 11B is an ON signal,
When the third main hall element 11C has an OFF signal, it can be detected that the rotation angle of the rotor exists in the section of 120 degrees to 180 degrees.

The first to third sub Hall elements 12A to 12
C is arranged at the same angular position as the first to third main hall elements 11A to 11C, and is shown in FIGS. 2B, 2D and 2F.
As shown in, the ON signal is output in a range where the magnetic flux density of the magnetic pole of the disk 10 is high, and an intermediate level signal having a signal output value lower than that of the ON signal is output corresponding to a medium magnetic flux density before and after the magnetic field. It is composed of a three-level type Hall element that outputs an off signal when the magnetic flux density decreases.

The angle range in which the ON signal is obtained is
The angle range set to be smaller than the angle range (180 degrees) of the ON signals of the first to third main hall elements 11A to 11C, and the total angle range of the ON signal and the intermediate level signals obtained on both sides of the ON signal is the first to third main halls. It is set to be larger than the angular range (180 degrees) of the ON signals of the elements 11A to 11C, and is set to invert the output signals of the first to third main hall elements 11A to 11C during the output of the intermediate level signal. ing.

First to third main hall elements 11A to 11C
It is assumed that the first to third sub Hall elements 12A to 12C are arranged at the same angular position, but they may be installed at angular positions slightly deviated from each other. First for the ON signal of 11A to 11C
The angular position at which the ON signal of each of the 3 to 3 sub Hall elements 12A to 12C and the intermediate level signal are output deviates to the front or rear.

In this case, when the shift amount is β and the latch width of the intermediate level signal is α, by using a Hall element whose latch width α is larger than the shift amount β, even if there is a shift, the range of the above setting is set. First to third main hall elements 11A to
11C and first to third sub-hall elements 12A to 12
C can be located.

The motor control section 2 includes a motor control unit 4, an inverter driver 5, an inverter 6,
And a power supply 7.

The motor control unit 4 includes first to third main hall elements 11A to 11C of the phase detector 3.
Based on the output signal from the rotor and the disk 10
The phase section is discriminated and the rotor rotation speed is calculated for each 60 degrees, and the magnitude and phase of the current flowing in the stator coil (not shown) are determined based on these information and the target torque given from the outside. A command signal is output to the inverter driver 5 so that the determined current is supplied.

Further, the motor control unit 4
Monitors the output signals of the first to third main hall elements 11A to 11C and the output signals of the first to third sub hall elements 12A to 12C, determines the failure of the phase detector 3, and the failure has occurred. At this time, a predetermined fail signal is output.

The operation will be described based on the processing flow of the failure determination of FIG. In the processing flow of FIG. 3, whether or not the absolute value of the signal deviation (11A-12A) between the output signal of the first main hall element 11A and the output signal of the first sub hall element 12A exceeds the fail determination threshold value Wfa. Step 1 of determining whether or not, the signal deviation (1 between the output signal of the second main Hall element 11B and the output signal of the second sub Hall element 12B
1B-12B) is the absolute value of the fail judgment threshold value Wfa
Step 2 of determining whether or not the signal exceeds the output signal of the third main Hall element 11C and the output signal of the third sub Hall element 12C (11C-12C)
Step 3 is provided to determine whether or not the absolute value of each exceeds the fail determination threshold value Wfa.

Then, in steps 1 to 3, when none of the absolute values of the signal deviation exceeds the fail judgment threshold value Wfa, it is judged to be normal, and the absolute value of the signal deviation in any one step is determined. Is above the fail determination threshold value Wfa, a fail signal is output in step 4.

FIGS. 4 and 5 show the operation of the failure determination. FIG. 4 shows the main hall element (see FIG. 4 (A)) 11A (or 11B, 11C) and the sub-halls under normal conditions. The output signal of the element (see FIG. 4B) 12A (or 12B, 12C) is shown, and the absolute value of the signal deviation of both output signals is as shown in FIG. It is output only when it is output from (12B, 12C), and the value does not exceed the fail determination threshold value Wfa and is determined to be normal.

However, for example, when a failure occurs in which the output signal of the main hall element 12A (12B, 12C) sticks to a so-called low level that outputs only an off signal as shown by the solid line in FIG. 5 (A). As shown in FIG. 5C, the absolute value of the signal deviation is determined by the sub Hall element 12A (1
2B, 12C) rises while the ON signal is being output and exceeds the fail determination threshold value Wfa, and the fail signal of step 4 is output.

Further, the main hall element 11A (11B,
When the output signal of FIG. 11C) sticks to a so-called high level that outputs only an ON signal, the absolute value of the signal deviation is output in a state where the absolute value of the signal deviation of FIG. , The main hall element 11A (11B,
11C), the fail determination threshold value Wfa is exceeded at the timing when the originally off signal is output.

In the failure judgment by outputting the fail signal, when the main hall element 11A (11B, 11C) is in the off state and the failure occurs, the rotation position of the disk 10 causes the failure in the main hall. Element 11A (11B, 11
When both C) and the sub-hall element 12A (12B, 12C) are in the ON signal output range, the determination can be immediately made even if the rotor is stopped without waiting for a change in the rotational position of the rotor.

Further, the main hall element 11A (11B,
11C) is in the ON state and is in failure, the main hall element 11A in which the rotational position of the rotor is in failure
(11B, 11C) and the sub Hall element 12A (12B,
12C) and 12C) are both in the OFF signal output range, the determination can be made immediately even if the rotor is stopped without waiting for a change in the rotational position of the rotor.

Further, the main hall element 11A (11B,
11C) is in the off state and is out of order, the position (sub Hall element 12A (12B, 12)
The position where the output signal of C) is outputting an intermediate level signal or an OFF signal), the main hall element 11A (11
B, 11C) is in the ON state and has a failure,
Positions other than the above conditions (sub Hall element 12A (12B,
Even if the output signal of 12C) is at the intermediate level signal or the position where the ON signal is being output), the rotor is rotated and the failure occurs when the rotor rotates and reaches the position that can be determined even when the rotor is stopped. You can judge.

The rotation angle in this case is the maximum and is the angle until the intermediate level signal output next changes to an ON signal or an OFF signal.
(11B, 11C) Angle 180 of ON signal output range of child
The angle is the sum of the degree and the width α of the intermediate level of the sub Hall element 12A (12B, 12C).

Therefore, in order to make a quick failure determination,
A three-level latch type Hall element having a small width α at an intermediate level is used as a sub Hall element 12A (12B, 12B).
It may be used for C), but if it is made too small, an erroneous determination occurs, so a certain width is necessary.

The embodiment described above has the following effects. That is, each Hall element 11A-
Sub Hall elements 12A to 12C at the same angular position as 11C.
And the Hall elements 11A (11B, 11B,
11C) and the output signals of the sub Hall elements 12A (12B, 12C) are compared to detect the failure of the Hall elements, so that the output signals of both Hall elements are constantly compared to determine an abnormal state and prompt It is possible to determine the failure, and this failure determination can be performed even when the rotor such as the rotor is stopped.

Further, the sub Hall element 12A (12B, 1
2C) outputs an ON signal in an angle range smaller than the Hall element 11A (11B, 11C), outputs an intermediate level signal lower than the ON signal outside the angle range of the ON signal, and outputs an OFF signal in other than these. The Hall element 11A includes a three-level latch type Hall element, and the angle range for outputting the ON signal and the intermediate level signal is formed to be larger than the ON signal angular range of the Hall element.
The output signal of the sub Hall element 12A (12B, 12C) near the signal inversion position of (11B, 11C) becomes an intermediate level signal, and the Hall element 11A (11B, 11C) and the sub Hall element 12A (12B, 12C) are attached. Even if the positions are deviated, the deviation of both signals in the vicinity of the signal inversion position of the Hall element 11A (11B, 11C) can be reduced, and erroneous detection prevention becomes easy.

Further, the hall element 11A (11B, 11
C) and the sub Hall element 12A (12B, 12C) when the difference in signal output exceeds a predetermined value, it is determined as a failure. Therefore, the failure can be determined even if the phase does not change, and the signal is near the signal inversion position. No misjudgment occurs.

FIG. 6 shows a rotation angle detecting device according to another embodiment of the present invention. The first to third main hall elements 11A to 11C have two levels in which an output signal similar to that shown in FIG. 1 is turned on and off. Type (see FIG. 6A), but first
.About.3 sub Hall elements 13A to 13C are of a magnetic flux proportional type (see FIG. 6B) capable of obtaining an output signal that continuously changes in proportion to the magnetic flux.

Then, the first to third main hall elements 11A
The signal deviation between (or 11B, 11C) and the first to third sub-hall elements 13A (or 13B, 13C) is at the signal inversion positions of the first to third main hall elements as shown by the solid line in FIG. 6 (C). Although the maximum, the fail judgment threshold value Wf
It will change below a.

However, when the output signal of the first to third main hall elements 11A (11B, 11C) sticks to the low level, the signal deviation changes as shown by the broken line in FIG. 6 (C), Part of the fail judgment threshold Wf
Since it exceeds a, a fail signal can be output.

Also, the first to third main hall elements 11A
When the output signal of (11B, 11C) sticks to a high level, the signal deviation is shifted by 180 degrees with respect to FIG. 6C as indicated by a broken line in FIG. 6D.
Since a change occurs and a part of them exceeds the fail determination threshold value Wfa, a fail signal can be output.

In this aspect, even if the first to third sub Hall elements 13A (13B and 13C) are arranged with respect to the first to third main Hall elements 11A (11B and 11C), the signal deviation is taken. Only the trajectory changes, and there is no erroneous determination due to displacement of the mounting position.

In this embodiment, in addition to the effect obtained by the first embodiment, the sub Hall element 13A
.. to 13C are magnetic flux proportional elements in which the output signal continuously changes in proportion to the magnetic flux, the signal inversion is gentle, and the Hall elements 11A to 11C and the sub Hall elements 13A to 13C.
Hall element 11A ~
The deviation of both signals in the vicinity of the signal inversion position of 11C can be reduced, and erroneous detection prevention becomes easy.

In each of the above-mentioned embodiments, the rotation angle detecting device applied to the phase detecting device for the rotor of the electric motor has been described. Can also be used.

Further, in each of the above embodiments, the rotation angle is detected by three Hall elements, but the present invention is not limited to this, and although not shown, for example, four or more Hall elements are used. It can also be applied to a rotation angle detection device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram in which a rotation angle detection device according to an embodiment of the present invention is applied to a motor control system.

FIG. 2 is a time chart showing an output state of the rotation angle detection device.

FIG. 3 is a flow chart showing a failure determination method of the rotation angle detection device.

FIG. 4 is a timing chart showing the operation of FIG.

5 is a timing chart showing another operation of FIG.

FIG. 6 is a timing chart showing another embodiment of the present invention.

[Explanation of symbols]

1 electric motor 2 Motor control unit 3 Phase detector (rotation angle detector) 4 Motor control unit 5 Inverter driver 6 inverter 10 disk (rotating body) 11A-11C Main Hall element 12A to 12C, 13A to 13C Sub Hall element

Continued front page    F-term (reference) 2F063 AA35 BA03 BC06 BD16 CA40                       DA01 DD07 GA52 KA04 LA01                       NA06                 2F077 AA04 NN02 PP12 QQ07 RR03                       TT31                 5H019 BB05 BB19 BB23

Claims (4)

[Claims] 1. A rotation angle detection for detecting a rotation angle position of a rotating body by combining output signals from ON / OFF two-level latch type Hall elements arranged at equal intervals on the circumference of the rotating body. The device is characterized in that a sub Hall element is arranged at the same angular position as the Hall element of each phase, and a failure of the Hall element is detected by comparing the output signals of the Hall element at the same angular position and the sub Hall element. Rotation angle detection device. 2. The rotation angle detecting device according to claim 1, wherein the sub-hall element is a magnetic flux proportional element whose output signal continuously changes in proportion to magnetic flux. 3. The sub Hall element outputs an ON signal in an angle range smaller than the Hall element, outputs an intermediate level signal lower than the ON signal outside the angle range of the ON signal, and outputs an OFF signal in other than these. 2. A three-level latch type Hall element for outputting, and an angular range for outputting an ON signal and an intermediate level signal is formed to be larger than an angular range for an ON signal of the Hall element. Rotation angle detection device. 4. The determination of the failure of the hall element is made when a difference between outputs of the hall element signal and the sub hall element signal exceeds a predetermined value. The rotation angle detection device described.