# US 10,501,113 B2 · Motor drive control device, electric power steering device, and vehicle

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- Number: US 10,501,113 B2
- Document ID: US10501113B2
- Status: Granted
- Kind: B2
- Application number: 16/073,883
- Filed: 2017-04-26
- Published: 2019-02-07
- Granted: 2019-12-10
- Earliest claimed: 2016-05-13
- Assignees: Nsk Ltd.
- Applicants: NSK Ltd.
- Inventors: Masaki Kuwahara; Shigeyuki Uematsu
- Web page: https://patentgrep.com/patent/US10501113B2

## CPC

- B62D 5/0487: {detecting motor faults (B62D5/0496 takes precedence)}
- B60R 16/033: characterised by the use of electrical cells or batteries (for propulsion puposes B60K1/04; supplying batteries to, or removing batteries from, vehicles B60S5/06; testing of charge state G01R31/36)
- B62D 5/0484: {for reaction to failures, e.g. limp home}
- B62D 15/021: {Determination of steering angle}
- G01B 7/30: for measuring angles or tapers; for testing the alignment of axes
- G01D 5/14: influencing the magnitude of a current or voltage
- G01D 5/244: influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
- G01D 5/24461: {by redundancy or plausibility}
- G01D 5/24485: {using other sensors}
- G07C 5/0808: {Diagnosing performance data (testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005)}
- H02P 6/16: Circuit arrangements for detecting position
- H02P 2203/05: Determination of the rotor position by using two different methods and/or motor models
- 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)
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- 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
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

To provide a motor drive control device, an electric power steering device, and a vehicle which can individually diagnose abnormalities of magnetic detection elements, designed in a multisystem configuration to include at least two systems, for each system. A motor drive control device includes two systems of first and second rotation information detection function units. The first and second rotation information detection function units include first and second rotation position information detection units and first and second rotation information detection units. The first and second rotation information detection units individually diagnose their own abnormalities based on first and second motor rotation position signals detected by the first and second rotation position information detection units.

## Claims

### Claim 1

A motor drive control device comprising:
an annular or disk-shaped magnet placed on a motor rotating shaft of an electric motor to be rotatable in synchronism with the motor rotating shaft and includes at least two different magnetic poles arranged alternately in a circumferential direction;
at least two systems of rotation information detection function units each including a rotation position information detection unit configured to detect a magnetic flux of the magnet which changes depending on a rotation position of the motor rotating shaft as rotation position information, a motor rotation angle calculation unit configured to calculate a motor rotation angle based on the rotation position information detected by the rotation position information detection unit, a rotation position information diagnosis unit configured to diagnose an abnormality of the rotation position information detected by the rotation position information detection unit, and a rotation change amount measurement unit configured to measure an amount of change in the rotation position of the electric motor; and
a motor drive control unit configured to control driving of the electric motor based on the motor rotation angle output from the at least two systems of the rotation information detection function units,
wherein the rotation position information detection unit includes a plurality of sensor elements configured to detect magnetic signals out of phase with each other as the rotation position information,
the electric motor is configured to apply a steering assist force to a steering shaft of a vehicle equipped with the motor drive control device,
the motor drive control device is configured to supply power from a battery of the vehicle to the at least two systems of the rotation information detection function units even while an ignition switch is OFF,
the rotation change amount measurement unit is configured to continuously measure the amount of change in the rotation position even while the ignition switch is OFF,
the rotation change amount measurement unit includes a change amount measurement unit configured to measure an amount of change in the rotation position of the electric motor based on the rotation position information detected by the rotation position information detection unit, a change amount storage unit configured to store the amount of change measured by the change amount measurement unit, and a measurement abnormality diagnosis unit configured to diagnose an abnormality of the change amount measurement unit and the change amount storage unit,
the motor drive control unit is configured to, when the rotation position information diagnosis unit diagnoses at least one of the at least two systems of the rotation information detection function units as abnormal, control driving of the electric motor based on the motor rotation angle output from another of the rotation information detection function units that is normal,
the motor drive control unit is configured to calculate a steering angle that is a rotation angle of the steering shaft based on the amount of change in the rotation position measured by the rotation change amount measurement unit when the ignition switch changes from OFF to ON, and calculate the steering angle based on the motor rotation angle while the ignition switch is subsequently kept ON, and control driving of the electric motor based on the calculated steering angle, and
the motor drive control unit is configured to, when the measurement abnormality diagnosis unit diagnoses at least one of the at least two systems of the rotation information detection function units as abnormal, calculate the steering angle based on the amount of change output from another of the rotation information detection function units that is normal.

### Claim 2 (depends on 1)

The motor drive control device according to claim 1, further including a power supply control unit configured to intermittently supply power from the battery of the vehicle to the at least two systems of the rotation information detection function units while the ignition switch is OFF.

### Claim 3 (depends on 2)

The motor drive control device according to claim 2, wherein the power supply control unit is configured to make switching from a state in which the power is intermittently supplied from the battery to a state in which the power is continuously supplied from the battery, when a motor rotational speed of the electric motor that is not less than a rotational speed set in advance is detected while the ignition switch is OFF.

### Claim 4 (depends on 2)

The motor drive control device according to claim 2, wherein the power supply control unit is configured to intermittently supply the power from the battery to the rotation position information detection unit, the rotation position information diagnosis unit, and the rotation change amount measurement unit in each of the at least two systems of the rotation information detection function units and cut off the power supplied to other constituent units, while the ignition switch is OFF.

### Claim 5 (depends on 1)

The motor drive control device according to claim 1, wherein each of the at least two systems of the rotation information detection function units includes an A/D converter configured to convert an analog signal corresponding to the rotation position information into a digital signal, a monitoring potential signal input unit configured to input an analog monitoring potential signal to the A/D converter, and an A/D converter diagnosis unit configured to compare the monitoring potential signal converted into a digital signal by the A/D converter with a preset comparison potential to diagnose an abnormality of the A/D converter based on the comparison result.

### Claim 6 (depends on 1)

An electric power steering device including the motor drive control device according to claim 1.

### Claim 7 (depends on 6)

A vehicle including the electric power steering device according to claim 6.