Motor drive device

Patent metadata

Field	Value
Publication number	US-9660561-B2
Application number	US-201514923192-A
Country	US
Kind code	B2
Filing date	Oct 26, 2015
Priority date	Jun 30, 2011
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A motor drive device having drive controller to control a motor for driving an electric vehicle wheel depending on position of magnetic poles using angle detection value sensed by a motor angle sensor; motor angle estimator to estimate an angle of a motor rotor without a rotation sensor; sensor malfunction determiner to determine malfunction of the sensor; sensor switcher to cause the controller to control using an estimation value of the rotor angle estimated by the estimator instead of the angle detection value sensed by the sensor once the determiner determines that the sensor malfunctions; and start-up rotor angle calculator to calculate an angle of the rotor from a counter electromotive voltage of the motor and to cause the controller to control using the calculated angle, when the motor is started up after stop of the motor in a state where the sensor is determined as malfunctioning by the determiner.

First claim

What is claimed is:

1. A motor drive device comprising:
a general drive controller configured to control a motor unit for driving a wheel of an electric vehicle depending on a position of magnetic poles by using an angle detection value sensed by a motor angle sensor provided at the motor unit;
a first motor angle estimator configured to estimate an angle of a motor rotor of the motor unit without using a rotation sensor;
a sensor malfunction determiner configured to determine a malfunction of the motor angle sensor;
a sensor switcher configured to cause the general drive controller to perform control using an estimation value of the motor rotor angle estimated by the first motor angle estimator instead of the angle detection value sensed by the motor angle sensor once the sensor malfunction determiner determines that the motor angle sensor malfunctions; and
a start-up rotor angle calculator configured to calculate an angle of the motor rotor from a counter electromotive voltage of the motor unit and to cause the general drive controller to perform control using the calculated angle, when the motor unit is started up after stop of the motor unit in a state where the motor angle sensor is determined as malfunctioning by the sensor malfunction determiner.

2. The motor drive device as claimed in claim 1 , wherein after the general drive controller is controlled with the angle calculated by the start-up rotor angle calculator for a determined time or for one cycle in electrical angle of the motor unit, the general drive controller is controlled with the output estimated by the first motor angle estimator.

3. The motor drive device as claimed in claim 1 , further comprising:
a second motor angle estimator configured to estimate an angle of the motor rotor from a detection signal sensed by a wheel rotational frequency sensor configured to sense a rotation speed of the wheel driven by the motor unit.

4. The motor drive device as claimed in claim 1 , wherein
the sensor malfunction determiner further determines a malfunction of the wheel rotational frequency sensor, and
the sensor switcher causes the general drive controller to perform control using an estimation value of the motor rotor angle estimated by the second motor angle estimator once the sensor malfunction determiner determines that the motor angle sensor malfunctions, and the sensor switcher causes the general drive controller to perform control using an estimation value of the motor rotor angle estimated by the first motor angle the wheel rotational frequency sensor malfunction.

5. The motor drive device as claimed in claim 4 , wherein the sensor malfunction determiner determines a malfunction of the motor angle sensor based on any one of or both an amount of change in the angle detection value sensed by the motor angle sensor for a given time period and a difference between a command value which is generated by the general drive controller to be supplied to the motor unit and a detection value in the motor unit.

6. The motor drive device as claimed in claim 1 , wherein
while the general drive controller controls the motor unit depending on the position of the magnetic poles using the angle detection value sensed by the motor angle sensor, the first motor angle estimator constantly estimates an angle of the motor rotor, compares an estimation value of the estimated motor rotor angle with the angle detection value sensed by the motor angle sensor, and performs a correction process such that a difference between the estimation value and the detection value is minimized.

7. The motor drive device as claimed in claim 6 , wherein the first motor angle estimator includes: a phase estimator configured to constantly estimate an angle of the motor rotor while the general drive controller controls the motor unit depending on the position of the magnetic poles using the angle detection value sensed by the motor angle sensor; a first comparison segment configured to compare an estimation value estimated by the phase estimator with the angle detection value sensed by the motor angle sensor; and a correction value storage/corrector configured to store a correction value that minimizes a difference between the estimation value and the detection value which difference is a result of the comparison, to determine the correction process based on the stored correction value according to any one of or both a rotational frequency obtained from the wheel rotational frequency sensor or a rotational frequency calculator and a command value which is generated by the general drive controller to be applied to the motor unit, and to perform the correction process.

8. The motor drive device as claimed in claim 3 , wherein in the case that the wheel rotational frequency sensor is configured to detect only a relative angle change by calculating intervals between pulses generated in response to rotation of the wheel and sensing a rotation speed of the wheel, the second motor angle estimator calculates a position of the magnetic poles of the motor rotor relative to a detection signal sensed by the wheel rotational frequency sensor based on the angle detection value sensed by the motor angle sensor when the motor unit rotates, and estimates an angle of the motor rotor from the detection signal sensed by the wheel rotational frequency sensor once switching is performed by the sensor switcher such that an estimation value of the motor rotor angle estimated by the second motor angle estimator is used.

9. The motor drive device as claimed in claim 3 , wherein the second motor angle estimator includes a magnetic pole position relationship storage configured to store a correlation between the wheel rotational frequency and the position of the magnetic poles by calculating the position of the magnetic poles in accordance with the detection signal sensed by the wheel rotational frequency sensor based on the angle detection value sensed by the motor angle sensor, while the sensor malfunction determiner determines that the motor angle sensor is normal.

10. The motor drive device as claimed in claim 3 , wherein in the case that the wheel rotational frequency sensor is configured to sense a rotation speed of the wheel by calculating intervals between pulses generated in response to rotation of the wheel, the second motor angle estimator is configured to estimate an angle of the motor rotor with multiplying pulses produced from the wheel rotational frequency sensor.

11. The motor drive device as claimed in claim 3 , wherein
in the case that the wheel rotational frequency sensor is configured to sense a rotation speed of the wheel by calculating intervals between pulses generated in response to rotation of the wheel, the second motor angle estimator is configured to estimate an angle of the motor rotor with measuring times between pulses produced from the wheel rotational frequency sensor.

12. The motor drive device as claimed in claim 3 , wherein
the first motor angle estimator calculates a position of the magnetic poles of the motor rotor once the sensor switcher performs switching to control using the motor rotor angle produced from the second motor angle estimator, and
the motor drive device further comprises a motor rotor angle corrector configured to correct a motor rotor angle estimated by the second motor angle estimator based on the calculated position of the magnetic poles of the motor rotor.

13. The motor drive device as claimed in claim 1 , wherein the motor unit is a motor unit in an electric vehicle in which each motor unit is configured to drive a single wheel.

14. The motor drive device as claimed in claim 13 , where

Assignees

• Ntn Toyo Bearing Co Ltd

Inventors

• Yamada Hiroyuki

Classifications

• H02K29/08

  using magnetic effect devices, e.g. Hall-plates, magneto-resistors (H02K29/12 takes precedence) · CPC title

• B60L2240/461

  Speed · CPC title

• B60L11/1803

  Operations & Transport · mapped topic

• B60L3/102

  of individual wheels · CPC title

• B60L2240/421

  Speed · CPC title