公开(公告)号：US20230387839A1

公开(公告)日：2023-11-30

申请号：US18303068

申请日：2023-04-19

Applicant: ALPS ALPINE CO., LTD.

Inventor： Ryo MAEDA ,  Ikuyasu MIYAKO ,  Wataru KIMURA

IPC: H02P6/18 ,  H02P21/18

CPC classification number: H02P6/188 ,  H02P21/18

Abstract: A rotation angle detecting method includes measuring a current flowing through a motor, and obtaining a rotation angle of the motor based on a value of the measured current. The obtaining of the rotation angle of the motor includes obtaining the rotation angle in an inertial rotation of the motor based on a rotational angular velocity of the motor immediately before a first time point, a time period from the first time point to a second time point, and a time period from the second time point to a third time point. The first time point is a time point at which driving of the motor is stopped, the second time point is a time point at which a polarity of the value of the measured current is inverted, and the third time point is a time point at which the value of the measured current becomes zero.

公开(公告)号：US20230280151A1

公开(公告)日：2023-09-07

申请号：US18158752

申请日：2023-01-24

Applicant: ALPS ALPINE CO., LTD.

Inventor： Ikuyasu MIYAKO ,  Wataru KIMURA ,  Ryo MAEDA

IPC: G01B7/30 ,  G01D5/244

CPC classification number: G01B7/30 ,  G01D5/24471

Abstract: A rotation angle detection device includes a current meter that measures a current flowing in a direct current motor; a filter that extracts a ripple component from the current; a ripple detector that detects a ripple from a signal that has passed through the filter; and a rotation angle detector that detects a rotation angle of the direct current motor based on the number of ripples. The rotation angle detector measures an observation period based on consecutive ripples, calculates an estimation period between the consecutive ripples based on the observation period, determines whether the observation period is within a normal range based on the estimation period and the observation period, and in response to determining that the observation period is within the normal range and an immediately-previous observation period is outside the normal range, calculates a number of correction ripples CRN so as to correct the number of the ripples.