Rotation angle detection device, and electric power steering device including same rotation angle detection device

Patent metadata

Field	Value
Publication number	US-2022024517-A1
Application number	US-201917312115-A
Country	US
Kind code	A1
Filing date	Jan 22, 2019
Priority date	Jan 22, 2019
Publication date	Jan 27, 2022
Grant date	—

Abstract

Provided is a rotation angle detection device including: a coefficient identification unit configured to identify, based on a sine signal and a cosine signal which are based on a rotation angle of a rotating body, coefficients of frequency components included in the sine signal and the cosine signal; a correction value calculation unit; and a rotation angle calculation unit. The coefficient identification unit is configured to identify, for each of integers M and N which satisfy a relationship in which M+N is equal to a positive constant, and each of which is equal to or larger than 0, a coefficient of each of (M+N−1)th order components included in the sine signal and the cosine signal, based on results of application of low-pass filters to products of an M-th power of the sine signal and an N-th power of the cosine signal.

First claim

1 . A rotation angle detection device, comprising:
a coefficient identification circuitry configured to identify, based on a sine signal and a cosine signal which are based on a rotation angle of a rotating body, coefficients of frequency components included in the sine signal and the cosine signal; a correction value calculator configured to calculate correction values based on the coefficients identified by the coefficient identification circuitry; and a rotation angle calculator configured to calculate the rotation angle of the rotating body based on values obtained by correcting one of the sine signal or the cosine signal, or both thereof, through use of the correction values.

2 . The rotation angle detection device according to claim 1 , wherein the coefficient identification circuitry is configured to identify, for each of integers M and N which satisfy a relationship in which M+N is equal to a positive constant, and each of which is equal to or larger than 0, a coefficient of each of (M+N−1)th order components included in the sine signal and the cosine signal, based on results of application of low-pass filters to products of an M-th power of the sine signal and an N-th power of the cosine signal.

3 . The rotation angle detection device according to claim 2 , wherein the coefficient identification circuitry is configured to identify, for each of integers M and N which satisfy a relationship in which M+N is equal to 1, and each of which is equal to or larger than 0, a coefficient of each of (M+N−1=0)th order components included in the sine signal and the cosine signal, based on results of application of low-pass filters to products of an M-th power of the sine signal and an N-th power of the cosine signal.

4 . The rotation angle detection device according to claim 3 , wherein the coefficient identification circuitry is further configured to identify, for each of integers M and N which satisfy a relationship in which M+N is equal to 3, and each of which is equal to or larger than 0, a coefficient of each of (M+N−1=2)nd order components included in the sine signal and the cosine signal, based on results of application of low-pass filters to products of an M-th power of the sine signal and an N-th power of the cosine signal.

5 . The rotation angle detection device according to claim 4 , wherein the correction value calculator is configured to calculate the correction values based further on a rotation angle signal one calculation cycle before which is input from the rotation angle calculator through a delay circuitry.

6 . The rotation angle detection device according to claim 2 , wherein the coefficient identification circuitry is configured to identify, for each of integers M and N which satisfy a relationship in which M+N is equal to 2, and each of which is equal to or larger than 0, a coefficient of each of (M+N−1=1)st order components included in the sine signal and the cosine signal, based on results of application of low-pass filters to products of an M-th power of the sine signal and an N-th power of the cosine signal.

7 . The rotation angle detection device according to claim 6 , wherein the coefficient identification circuitry is further configured to identify, for each of integers M and N which satisfy a relationship in which M+N is equal to 4, and each of which is equal to or larger than 0, a coefficient of each of (M+N−1=3)rd order components included in the sine signal and the cosine signal, based on results of application of low-pass filters to products of an M-th power of the sine signal and an N-th power of the cosine signal.

8 . A rotation angle detection device, comprising:
an intermediate signal generator configured to generate an intermediate signal based on a product of a sine signal and a cosine signal which are based on a rotation angle of a rotating body; a multiplicator configured to multiply the intermediate signal by one of the sine signal or the cosine signal; an adder-subtractor configured to add the other one of the sine signal or the cosine signal and an output of the multiplicator to each other or to subtract the output of the multiplicator from the other one of the sine signal or the cosine signal; and a rotation angle calculator configured to calculate the rotation angle of the rotating body based on the one of the sine signal or the cosine signal and on an output of the adder-subtractor.

9 . The rotation angle detection device according to claim 8 , wherein the intermediate signal generator includes:
a multiplier configured to calculate the product of the sine signal and the cosine signal; and a low-pass filter configured to remove frequency components equal to or higher than twice a frequency of fundamental waves of the sine signal and the cosine signal from an output of the multiplier.

10 . An electric power steering device, comprising the rotation angle detection device of claim 1 ,
wherein the rotating body is a motor configured to generate an assist torque for electric power steering, and wherein the electric power steering device is configured to control the motor based on a rotation angle signal output from the rotation angle detection device.

Assignees

• Mitsubishi Electric Corp

Inventors

• Mori Tatsuya
• Furukawa Akira

Classifications

• B62D15/021 Primary

  Determination of steering angle · CPC title

• G01D5/24476 Primary

  Signal processing (G01D5/2448 - G01D5/24495 take precedence) · CPC title

• G01B7/30

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• G01D3/02

  with provision for altering or correcting the law of variation · CPC title

• G01D5/204

  by influencing the mutual induction between two or more coils (G01D5/22 takes precedence) · CPC title