Motor drive device and motor drive system

Patent metadata

Field	Value
Publication number	US-10910968-B2
Application number	US-201916451192-A
Country	US
Kind code	B2
Filing date	Jun 25, 2019
Priority date	Jun 28, 2018
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

The present disclosure provides a motor drive device and a motor drive system for improving a control stability despite an imbalance in zero crossing points in a sensorless motor of which position of a rotor is estimated by a counter electromotive force. The motor drive device includes: a position detector configured to detect a rotational position of a rotor of a motor by detecting a plurality of zero crossing points of a counter electromotive force induced in the motor; and a controller configured to control the motor by estimating a phase change timing based on a time interval between a current zero crossing point and a previous zero crossing point of a same state as the current zero crossing point among the plurality of zero crossing points detected by the position detector.

First claim

What is claimed is:

1. A motor drive device, comprising:
a position detector configured to detect a rotational position of a rotor of a motor by detecting a plurality of zero crossing points of a counter electromotive force induced in the motor; and
a controller configured to control the motor by estimating a phase change timing based on a time interval between a current zero crossing point and a previous zero crossing point of a same state as the current zero crossing point among the plurality of zero crossing points detected by the position detector,
wherein the controller is configured to:
determine a rising or falling state of the counter electromotive force at an instant at which the current zero crossing point T 0 is detected, and
estimate the phase change timing based on the time interval between the current zero crossing point and the previous zero crossing point of the same state as the current zero crossing point.

2. The motor drive device of claim 1 , wherein the controller estimates the phase change timing according to equation 2:

t
trans

=

T
⁡

(

n
-
1

)

2

(
2
)

where T(n−1) denotes a time interval between the previous zero crossing point T 2 having a same rising and falling state as the current zero crossing point T 0 detected recently and the next zero crossing point T 1 of the previous zero crossing point T 2 .

3. The motor drive device of claim 2 , wherein the controller determines a lead angle from a waveform of the counter electromotive force detected by the position detector and estimates the phase change timing by additionally taking into account the lead angle.

4. The motor drive device of claim 3 , wherein the controller calculates a lead angle time according to equation 4:

t
adv

=

x
⁢

⁢
°

120
⁢
°

⁢

{

T
⁡

(
n
)

+

T
⁡

(

n
-
1

)

}

(
4
)

where x denotes the lead angle, and T(n) denotes a time interval between the current zero crossing point T 0 and a prior previous zero crossing point T 1 occurred just before.

5. The motor drive device of claim 4 , wherein the controller estimates the phase change timing by taking into account the lead angle according to equation 5:

t

trans
⁡

(
adv
)

=

T
⁡

(

n
-
1

)

2

+

x
⁢

⁢
°

120
⁢
°

⁢

{

T
⁡

(
n
)

+

T
⁡

(

n
-
1

)

}

(
5
)

6. A motor drive system, comprising:
a motor configured to generate a torque and comprising a rotor;
a position detector configured to detect a rotational position of the rotor of the motor by detecting a plurality of zero crossing points of a counter electromotive force induced in the motor; an

Assignees

• Korea Electronics Technology

Inventors

• Park Joonsung
• Choi Junhyuk
• Kim Jinhong
• Hyon Byongjo
• Noh Yongsu
• Joo Dongmyoung

Classifications

• G01R19/175

  Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero · CPC title

• H02P6/182 Primary

  using back-emf in windings · CPC title

• Y10S388/9281

  Counter or back emf, CEMF · CPC title

• Y10S388/9072

  Bridge circuit · CPC title

• H02P6/085

  in a bridge configuration · CPC title