# US 10,871,365 B2 · Angle detection device and electric power steering apparatus

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- Number: US 10,871,365 B2
- Document ID: US10871365B2
- Status: Granted
- Kind: B2
- Application number: 15/748,228
- Filed: 2016-05-31
- Published: 2018-09-06
- Granted: 2020-12-22
- Earliest claimed: 2015-11-26
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Akira Furukawa; Yu Kawano; Yuji Takizawa
- Web page: https://patentgrep.com/patent/US10871365B2

## CPC

- G01B 7/30: for measuring angles or tapers; for testing the alignment of axes
- B62D 5/0463: {calculating assisting torque from the motor based on driver input}
- B62D 6/10: characterised by means for sensing {or determining} torque
- G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)}
- H02P 6/10: Arrangements for controlling torque ripple, e.g. providing reduced torque ripple
- H02P 6/16: Circuit arrangements for detecting position
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

Included are: a sensor magnet which rotates integrally with a rotating shaft centering on the rotating shaft, and generates a magnetic field for angle detection which is for detecting the angle of rotation; a first sensor and a second sensor each of which is arranged opposite to the sensor magnet at a position separated in angle by 90 degrees on the circumference centered on the rotating shaft, and outputs a signal corresponding to the magnetic field for angle detection; and an angle calculator that calculates a rotation angle by using the signals from the first sensor and the second sensor.

## Claims

### Claim 1

An angle detection device comprising:
a ring-shaped sensor magnet configured to rotate integrally with a rotating shaft centering on the rotating shaft, and to generate a magnetic field for angle detection that is for detecting the angle of rotation;
a first sensor and a second sensor each configured to be arranged on a surface opposite to the sensor magnet at a position separated in angle by 90 degrees on a circumference centered on the rotating shaft, a distance from a center of the rotating shaft to the first sensor and the second sensor being smaller than a distance from the center of the rotating shaft to an outer radial edge of the sensor magnet, and to output a signal corresponding to the magnetic field for angle detection; and
an angle calculator configured to calculate a rotation angle by using the signals from the first sensor and the second sensor,
wherein the signals outputted by the first sensor and the second sensor according to the magnetic field for angle detection are a sine signal and a cosine signal; and
the angle calculator sets the average of the angle calculated from the sine signal and the cosine signal which are outputted by the first sensor and the angle calculated from the sine signal and the cosine signal which are outputted by the second sensor, as a rotation angle,
wherein the first sensor is arranged at a first single position on the surface opposite to the sensor magnet and the second sensor is arranged at a second single position on the surface opposite to the sensor magnet separated in angle by 90 degrees from the first single position.

### Claim 2 (depends on 1)

The angle detection device according to claim 1,
wherein the signals outputted by the first sensor and the second sensor according to the magnetic field for angle detection are an angle; and
the angle calculator sets the average of the angle outputted by the first sensor and the angle outputted by the second sensor as a rotation angle.

### Claim 3 (depends on 1)

The angle detection device according to claim 1,
wherein the angle calculator sets the average of the angle calculated from the sine signal outputted by the first sensor and the sine signal outputted by the second sensor and the angle calculated from the cosine signal outputted by the first sensor and the cosine signal outputted by the second sensor, as a rotation angle.

### Claim 4 (depends on 1)

The angle detection device according to claim 1,
wherein the angle calculator calculates the rotation angle from a sine signal after correction which is obtained from the sum or the difference of Ks times of the sine signal outputted by the first sensor and Kc times of the cosine signal outputted by the second sensor, and a cosine signal after correction which is obtained from the sum or the difference of Kc times of the cosine signal outputted by the first sensor and Ks times of the sine signal outputted by the second sensor.

### Claim 5 (depends on 4)

The angle detection device according to claim 4,
wherein the angle calculator calculates the rotation angle after multiplying the ratio of amplitude of the fundamental waves of the sine signal after correction and the cosine signal after correction and any of the signals together.

### Claim 6 (depends on 1)

The angle detection device according to claim 1,
wherein the angle calculator calculates the rotation angle from a sine signal after correction which is obtained from the sum of the sine signal outputted by the first sensor and the sine signal outputted by the second sensor, and a cosine signal after correction which is obtained from the sum of the cosine signal outputted by the first sensor and the cosine signal outputted by the second sensor.

### Claim 7 (depends on 1)

The angle detection device according to claim 1,
wherein the angle calculator calculates a rotation angle after m time correction (where, m is a natural number) by correcting a 4nth order (where, n is a natural number) angle error with respect to the rotation angle calculated by the signals of the first sensor and the second sensor.

### Claim 8 (depends on 1)

An electric power steering apparatus comprising:
the angle detection device as set forth in claim 1; and
an AC rotary machine configured to generate assist torque that is for assisting driver's steering.

### Claim 9

An angle detection device comprising:
a ring-shaped sensor magnet configured to rotate integrally with a rotating shaft centering on the rotating shaft, and to generate a magnetic field for angle detection that is for detecting the angle of rotation;
a first sensor and a second sensor each configured to be arranged on a surface opposite to the sensor magnet at a position separated in angle by 90 degrees on a circumference centered on the rotating shaft, a distance from a center of the rotating shaft to the first sensor and the second sensor being smaller than a distance from the center of the rotating shaft to an outer radial edge of the sensor magnet, and to output a signal corresponding to the magnetic field for angle detection; and
an angle calculator configured to calculate a rotation angle by using the signals from the first sensor and the second sensor,
wherein the signals outputted by the first sensor and the second sensor according to the magnetic field for angle detection are a sine signal and a cosine signal; and
the angle calculator calculates the rotation angle from a sine signal after correction which is obtained from the sum or the difference of Ks times of the sine signal outputted by the first sensor and Kc times of the cosine signal outputted by the second sensor, and a cosine signal after correction which is obtained from the sum or the difference of Kc times of the cosine signal outputted by the first sensor and Ks times of the sine signal outputted by the second sensor, wherein either of gain Ks to be multiplied to the sine signal or gain Kc to be multiplied to the cosine signal is 1; and
the other is based on the ratio of (2p+1)th order components (where, p is a natural number) of the sine signal and the cosine signal.

### Claim 10 (depends on 9)

An electric power steering apparatus comprising:
the angle detection device as set forth in claim 9; and
an AC rotary machine configured to generate assist torque that is for assisting driver's steering.

### Claim 11

An angle detection device comprising:
a ring-shaped sensor magnet configured to rotate integrally with a rotating shaft centering on the rotating shaft, and to generate a magnetic field for angle detection that is for detecting the angle of rotation;
a first sensor and a second sensor each configured to be arranged on a surface opposite to the sensor magnet at a position separated in angle by 90 degrees on a circumference centered on the rotating shaft, a distance from a center of the rotating shaft to the first sensor and the second sensor being smaller than a distance from the center of the rotating shaft to an outer radial edge of the sensor magnet, and to output a signal corresponding to the magnetic field for angle detection; and
an angle calculator configured to calculate a rotation angle by using the signals from the first sensor and the second sensor,
wherein the signals outputted by the first sensor and the second sensor according to the magnetic field for angle detection are a sine signal and a cosine signal; and
the angle calculator sets the average of the angle calculated from the sine signal and the cosine signal which are outputted by the first sensor and the angle calculated from the sine signal and the cosine signal which are outputted by the second sensor, as a rotation angle,
wherein the angle calculator calculates the rotation angle from the sine signal and the sine signal at the position separated by 90 degrees when the cosine signal of one of the sensors fails, or calculates the rotation angle from the cosine signal and the cosine signal at the position separated by 90 degrees when the sine signal of one of the sensors fails.

### Claim 12

An angle detection device comprising:
a ring-shaped sensor magnet configured to rotate integrally with a rotating shaft centering on the rotating shaft, and to generate a magnetic field for angle detection that is for detecting the angle of rotation;
a first sensor and a second sensor each configured to be arranged on a surface opposite to the sensor magnet at a position separated in angle by 90 degrees on a circumference centered on the rotating shaft, a distance from a center of the rotating shaft to the first sensor and the second sensor being smaller than a distance from the center of the rotating shaft to an outer radial edge of the sensor magnet, and to output a signal corresponding to the magnetic field for angle detection; and
an angle calculator configured to calculate a rotation angle by using the signals from the first sensor and the second sensor,
wherein the signals outputted by the first sensor and the second sensor according to the magnetic field for angle detection are a sine signal and a cosine signal; and
the angle calculator sets the average of the angle calculated from the sine signal and the cosine signal which are outputted by the first sensor and the angle calculated from the sine signal and the cosine signal which are outputted by the second sensor, as a rotation angle,
wherein in the angle calculator, at least one of the sine signal, the cosine signal, the sine signal after correction, or the cosine signal after correction, which is used for calculating the rotation angle is one in which a (2q-1)th order (where, q is a natural number) signal error is corrected.

### Claim 13 (depends on 12)

The angle detection device according to claim 12,
wherein the angle calculator corrects the signal error by a previous rotation angle value.

### Claim 14 (depends on 12)

The angle detection device according to claim 12,
wherein the angle calculator corrects the signal error by an estimated rotation angle based on a previous rotation angle value.

### Claim 15

An angle detection device comprising:
a ring-shaped sensor magnet configured to rotate integrally with a rotating shaft centering on the rotating shaft, and to generate a magnetic field for angle detection that is for detecting the angle of rotation;
a first sensor and a second sensor each configured to be arranged on a surface opposite to the sensor magnet at a position separated in angle by 90 degrees on a circumference centered on the rotating shaft, a distance from a center of the rotating shaft to the first sensor and the second sensor being smaller than a distance from the center of the rotating shaft to an outer radial edge of the sensor magnet, and to output a signal corresponding to the magnetic field for angle detection; and
an angle calculator configured to calculate a rotation angle by using the signals from the first sensor and the second sensor, wherein the angle calculator calculates the rotation angle from output information of the other sensor when one of the sensors fails, and calculates a rotation angle after m time correction (where, m is a natural number) by correcting a 2nth order (where, n is a natural number) angle error with respect to the rotation angle.

### Claim 16 (depends on 15)

An electric power steering apparatus comprising:
the angle detection device as set forth in claim 15; and
an AC rotary machine configured to generate assist torque that is for assisting driver's steering.