Control method for three-phase dc brush less motor, control device, and image forming device

Patent metadata

Field	Value
Publication number	US-10020760-B2
Application number	US-201615181633-A
Country	US
Kind code	B2
Filing date	Jun 14, 2016
Priority date	Jun 22, 2015
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A control method for a three-phase DC brushless motor including a rotor that includes a plurality of magnetic poles and that is rotatable, a stator that includes a plurality of magnetic field generation parts to generate a magnetic field to be a driving source of the rotor, and a sensor to detect a magnetic pole of the rotor which pole passes through a first position in the stator is provided, the method including: detecting in which the sensor detects a first magnetic pole of the rotor which pole passes through the first position; estimating, based on a result of the detection of the first magnetic pole, time until the first magnetic pole reaches a second position in the stator; and controlling the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position.

First claim

What is claimed is:

1. A control method for a three-phase DC brushless motor including a rotor that includes a plurality of magnetic poles and that is rotatable, a stator that includes a plurality of magnetic field generation parts to generate a magnetic field to be a driving source of the rotor, and a sensor to detect a magnetic pole of the rotor which pole passes through a first position in the stator, the method comprising:
rotating the rotor at least a target number of rotations;
detecting a first magnetic pole of the rotor when the first magnetic pole passes through the first position;
estimating, based on a result of the detection of the first magnetic pole, time until the first magnetic pole reaches a second position in the stator; and
controlling, based on a result of the estimation of the time until the second position is reached, the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position.

2. The control method for a three-phase DC brushless motor according to claim 1 , further comprising:
first count starting in which counting by a first counter is started with time, at which the sensor detects the first magnetic pole passing through the first position, as first reference time;
a first estimation of the time from the first reference time until the first magnetic pole reaches the second position in the stator;
controlling, based on the estimated time, the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position;
second count starting in which counting by a second counter is started with time, at which the sensor detects a second magnetic pole of the rotor which magnetic pole passes through the first position, as second reference time;
a second estimation of the time from the second reference time to time until the second magnetic pole reaches the second position in the stator; and
controlling, based on the time until the second magnetic pole reaches the second position in the stator which time is estimated in the second estimating, the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the second magnetic pole passes through the second position.

3. The control method for a three-phase DC brushless motor according to claim 1 , further comprising:
activating a free-run counter that presents elapse of time by counting up in a certain time interval;
acquiring a first value of the free-run counter in a case where the sensor detects the first magnetic pole passing through the first position;
calculating, based on the first value, a second value of the free-run counter which value corresponds to time at which the first magnetic pole passes through the second position in the stator; and
controlling, in a case where a value of the free-run counter becomes a second value, the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position.

4. The control method for a three-phase DC brushless motor according to claim 1 , wherein
the rotor is rotatable in both of a clockwise direction and a counterclockwise direction, and
when the rotor is rotated in the counterclockwise direction, the plurality of magnetic field generation parts is controlled on the assumption that a second position in the stator is in a position symmetrical, in a direction of a rotary shaft of the rotor, with a second position in the stator in a case where the rotor is rotated in the clockwise direction, a straight line which connects the first position and a center point of a rotation of the rotor being an axis of symmetry.

5. The control method for a three-phase DC brushless motor according to claim 4 , wherein
when a signal from the sensor is received and a control unit, which is configured to estimate time until the first magnetic pole reaches the second position in the stator, rotates the rotor in the counterclockwise direction, the signal received from the sensor is inverted and read.

6. A control device comprising:
a control circuit configured to control a three-phase DC brushless motor including a rotor that includes a plurality of magnetic poles and that is rotatable, a stator that includes a plurality of magnetic field generation parts to generate a magnetic field to be a driving source of the rotor, and a sensor to detect a magnetic pole of the rotor which magnetic pole passes through a first position in the stator, wherein the control circuit
rotates the rotor at least a target number of rotations;
acquires a result of detection, which is performed by the sensor, of a first magnetic pole of the rotor which magnetic pole passes through the first position,
estimates, based on the result of the detection of the first magnetic pole, time until the first magnetic pole reaches a second position in the stator, and
controls, based on a result of the estimation of the time until the second position is reached, the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position.

7. The control device according to claim 6 , wherein
the control circuit makes a first counter start counting with time, at which the sensor detects the first magnetic pole passing through the first position, as first reference time,
estimates the time from the first reference time to time until the first magnetic pole reaches the second position in the stator,
controls the plurality of magnetic field generation parts based on the first time in such a manner that a suitable magnetic field is generated when the first magnetic pole passes through the second position,
makes a second counter start counting with time, at which the sensor detects a second magnetic pole of the rotor which magnetic pole passes through the first position, as second reference time,
estimates second time from the second reference time to time until the second magnetic pole reaches the second position in the stator, and
controls the plurality of magnetic field generation parts based on the second time in such a manner that a suitable magnetic field is generated when the second magnetic pole passes through the second position.

8. The control device according to claim 6 , wherein
the control circuit activates a free-run counter that presents elapse of time by counting up in a certain time interval,
acquires a first value of the free-run counter in a case where the sensor detects the first magnetic pole passing through the first position,
calculates, based on the first value, a second value of the free-run counter which value corresponds to time at which the first magnetic pole passes through the second position in the stator, and
controls, when a value of the free-run counter becomes the second value, the plurality of magnetic field generation parts in such a manner that a suitable magnetic field is generated in a case where the first magnetic pole passes through the second position.

9. The control device according to claim 6 , wherein
the rotor is rotatable in both of a clockwise direction and a counterclockwise direction, and
when the rotor is rotated in the counterclockwise direction, the control circuit controls the plurality of magnetic field generation parts on the assumption that a second position in the stator is in a position symmetrical, in a direction of a rotary shaft of the rotor, with a second position in the stator in a case where the rotor is rotated in the clockwise direction,

Assignees

• Konica Minolta Inc

Inventors

• Tachibana Yuta
• Sakai Katsuhide
• Koide Yasuhiro
• Tatsumoto Yuhei

Classifications

• G03G15/80

  Details relating to power supplies, circuits boards, electrical connections · CPC title

• H02P6/16

  Circuit arrangements for detecting position · CPC title

• G03G15/5008

  Driving control for rotary photosensitive medium, e.g. speed control, stop position control · CPC title

• H02P6/15 Primary

  Controlling commutation time · CPC title

• G03G15/757

  Drive mechanisms for photosensitive medium, e.g. gears · CPC title