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US-12627245-B2 - Phase angle detection system, control device, and phase angle detection method

US12627245B2US 12627245 B2US12627245 B2US 12627245B2US-12627245-B2

Abstract

A phase angle detection system according to one aspect of the embodiment detects a phase angle of an electric motor in a drive system provided with a transmission unit that changes a rotation speed of the electric motor. The phase angle detection system includes a first sensor, a second sensor, and an arithmetic processing unit. The first sensor outputs a first signal for detecting at least a specific phase angle of a rotor of the electric motor. The second sensor outputs a second signal capable of detecting an amount of rotation of an output axis of the transmission unit. The arithmetic processing unit calculates, with an amount of deviation included in a result of the detection of a specific phase angle by the first signal defined for each rotational direction of the electric motor in advance, an estimated value of an absolute angle of the rotor of the electric motor using the amount of deviation of the first signal determined by a rotational direction of the electric motor, a result of the detection of the first signal, and the second signal.

Inventors

  • Ayame KOJIMA MAKIMURA
  • Yusuke Ishimaru
  • Shunsuke TOBAYASHI

Assignees

  • TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATION

Dates

Publication Date
20260512
Application Date
20221013

Claims (12)

  1. 1 . A phase angle detection system of an electric motor in a drive system, which is provided with a transmission unit that changes a rotation speed of an electric motor, comprising: a first sensor configured to output a first signal for detecting at least a specific phase angle of a rotor of the electric motor; a second sensor configured to output a second signal capable of detecting an amount of rotation of an output axis of the transmission unit; and an arithmetic processing unit configured to calculate, with an amount of deviation included in a result of the detection of a specific phase angle by the first signal defined for each rotational direction of the electric motor in advance, an estimated value of an absolute angle of the rotor of the electric motor using the amount of deviation of the first signal determined by a rotational direction of the electric motor, a result of the detection of the first signal, and the second signal.
  2. 2 . The phase angle detection system according to claim 1 , wherein the arithmetic processing unit detects a rotational direction of the output axis on the basis of the second signal and determines the amount of deviation corresponding to the detected rotational direction.
  3. 3 . The phase angle detection system according to claim 2 , wherein the arithmetic processing unit counts a pulse signal included in the second signal to detect an amount of rotation after detection of the first signal, and sets the counted amount of rotation to an initial value in response to the detection of the first signal.
  4. 4 . The phase angle detection system according to claim 1 , wherein the arithmetic processing unit detects a rotational direction of the output axis on the basis of the second signal, calculates the estimated value of the absolute angle of the rotor using a first amount of deviation among amounts of deviation corresponding to a first rotational direction when a rotation of the first rotational direction of the output axis is detected, and calculates an estimated value of an absolute angle of the rotor using a second amount of deviation among amounts of deviation corresponding to a second rotational direction when a rotation of the second rotational direction of the output axis is detected.
  5. 5 . The phase angle detection system according to claim 1 , wherein the first sensor includes a magnetic unit that generates an unevenness of a magnetic force around an axis of the electric motor, and a magnetic sensor that detects the magnetic force larger than a predetermined value.
  6. 6 . The phase angle detection system according to claim 5 , wherein the magnetic unit includes a magnet that generates an unevenness of a magnetic force around an axis of the electric motor, and is disposed on the axis of the electric motor.
  7. 7 . The phase angle detection system according to claim 6 , wherein the first sensor includes a magnetic sensor that is capable of detecting an approach of the magnet disposed on the axis.
  8. 8 . The phase angle detection system according to claim 1 , wherein an amount of deviation included in a result of detection of the specific phase angle is defined to compensate for a detection error of the first sensor.
  9. 9 . The phase angle detection system according to claim 8 , wherein an amount of deviation included in the result of the detection of the specific phase angle is defined to compensate for a detection error of the first sensor that varies depending on a rotational direction of the electric motor.
  10. 10 . The phase angle detection system according to claim 1 , wherein the arithmetic processing unit detects at least an amount of offset from a specific phase angle of the rotor of the electric motor on the basis of the second signal.
  11. 11 . A control device of a drive system provided with a transmission unit that changes a rotation speed of an electric motor, comprising: an arithmetic processing unit configured to acquire a first signal for detecting at least a specific phase angle of a rotor of the electric motor from a first sensor, to acquire a second signal capable of detecting an amount of rotation of an output axis of the transmission unit from a second sensor, and to calculate, with an amount of deviation included in a result of the detection of the specific phase angle by the first signal defined for each rotational direction of the electric motor in advance, an estimated value of an absolute angle of the rotor of the electric motor using the amount of deviation of the first signal determined by a rotational direction of the electric motor, a result of the detection of the first signal, and the second signal; and a controller configured to control the electric motor using the estimated value of the absolute angle of the rotor of the electric motor.
  12. 12 . A phase angle detection method of an electric motor in a drive system provided with a transmission unit that changes a rotation speed of the electric motor, comprising: outputting, by a first sensor, a first signal for detecting at least a specific phase angle of a rotor of the electric motor; outputting, by a second sensor, a second signal capable of detecting an amount of rotation of an output axis of the transmission unit; and calculating, with an amount of deviation included in a result of the detection of the specific phase angle by the first signal defined for each rotational direction of the electric motor in advance, an estimated value of an absolute angle of the rotor of the electric motor using the amount of deviation of the first signal determined by a rotational direction of the electric motor, a result of the detection of the first signal, and the second signal.

Description

TECHNICAL FIELD Embodiments of the present invention relate to a phase angle detection system, a control device, and a phase angle detection method. BACKGROUND ART There is a rotary encoder that outputs an A phase/B phase pulse for detecting the relative angle of an axis and a pulse (referred to as Z pulse) for detecting the absolute angle of the axis. Incidentally, a transmission unit such as a gear or a friction wheel may be provided on an axis of a rotor of an electric motor, and a rotary encoder may be provided on an output axis of this transmission unit. In such a configuration, even if a rotary encoder is used to detect rotation of the output axis of the transmission unit, it has not been easy to detect a position of the rotor of the electric motor on the basis of the Z pulse output by this rotary encoder. CITATION LIST Patent Document Patent Document 1 Japanese Unexamined Patent Application, First Publication No. 2018-29458 SUMMARY OF INVENTION Technical Problem An object of the present invention is to provide a phase angle detection system, a control device, and a phase angle detection method that enable detection of a position of a rotor of an electric motor in a configuration in which a rotary encoder is provided on an output axis of a transmission unit that changes a rotation speed of an electric motor. Solution to Problem A phase angle detection system according to the embodiment detects a phase angle of an electric motor in a drive system provided with a transmission unit that changes a rotation speed of the electric motor. The phase angle detection system includes a first sensor, a second sensor, and an arithmetic processing unit. The first sensor outputs a first signal for detecting at least a specific phase angle of a rotor of the electric motor. The second sensor outputs a second signal capable of detecting an amount of rotation of an output axis of the transmission unit. The arithmetic processing unit calculates, with an amount of deviation included in a result of the detection of a specific phase angle by the first signal defined for each rotational direction of the electric motor in advance, an estimated value of an absolute angle of the rotor of the electric motor using the amount of deviation of the first signal determined by a rotational direction of the electric motor, a result of the detection of the first signal, and the second signal. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an overhead view of a drive system to which a phase angle detection system of an embodiment is applied. FIG. 2 is a configuration diagram of the phase angle detection system of the embodiment. FIG. 3 is a configuration diagram of a control device of the embodiment. FIG. 4 is a diagram for describing generation of a Z pulse of the embodiment. FIG. 5 is a diagram for describing the generation of the Z pulse of the embodiment. FIG. 6 is a diagram for describing the generation of the Z pulse of the embodiment. FIG. 7 is a flowchart of position detection processing of the embodiment. DESCRIPTION OF EMBODIMENTS Hereinafter, a phase angle detection system, a control device, and a phase angle detection method according to embodiments will be described with reference to the drawings. In addition, in the following description, components having the same or similar functions are given the same reference numerals. Then, redundant descriptions of those configurations may be omitted. Note that being electrically connected is sometimes simply referred to as “being connected.” Note that a “speed of an axis” refers to a rotational angular speed or an angular speed of the axis. A “position of the axis” refers to a rotation angle (mechanical angle) or a phase of the axis. FIG. 1 is an overhead view of a drive system 1D to which the phase angle detection system 1 of the embodiment is applied. FIG. 2 is a configuration diagram of the phase angle detection system 1 of the embodiment. The drive system 1D includes, for example, a synchronous motor 2 (M), an inverter 3 (INV), a position sensor 4 (first sensor, PS), a transmission 5 (transmission unit, G), and an encoder 6 (second sensor, PS), and a control device 10. The drive system 1D does not include the phase angle detection system 1. The phase angle detection system 1 includes, for example, a position sensor 4 disposed on an axis 2S of the synchronous motor 2, an encoder 6 disposed on an output axis of the transmission 5, and at least one of functional units constituting the control device 10. For example, the control device 10 includes a position speed calculation unit 11 (arithmetic processing unit, VEL or POS CALC), a subtractor 12, and a controller 13 (CONT). The position speed calculation unit 11 is an example of the phase angle detection system 1 described above. The synchronous motor 2 includes a main body, a stator (not shown), a stator winding (not shown), a rotor (not shown), the axis 2S connected to the rotor, and the like. The synchronous motor 2 is, for example, an ex