Motor drive control device, fan, and motor drive control method

Patent metadata

Field	Value
Publication number	US-11750122-B2
Application number	US-202117759445-A
Country	US
Kind code	B2
Filing date	Jan 22, 2021
Priority date	Feb 12, 2020
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

A motor drive control device capable of determining a drive state of a motor is provided. The motor drive control device includes a plurality of motor drive circuits performing, based on drive control signals (Sca1 and Sca2) for controlling the number of rotations of a motor, control of energization of the motor and outputting FG signals (fg1 and fg2) having a cycle corresponding to the actual number of rotations of the motor, a composite signal generation circuit receiving an input of each of the FG signals output from the motor drive circuits and generating a composite signal by combining input signals, and a drive control circuit generating, based on a speed command signal indicating a target number of rotations of the motor, the drive control signals and outputting the drive control signals to each of the motor drive circuits. The FG signals output from the motor drive circuits have a phase difference from each other.

First claim

The invention claimed is:

1. A motor drive control device comprising:
a plurality of motor drive circuits configured to perform, based on a drive control signal configured to control the number of rotations of a motor, control of energization of the motor and output FG signals having a cycle corresponding to an actual number of rotations of the motor;
a composite signal generation circuit configured to receive an input of the FG signals output from the plurality of motor drive circuits and generate a composite signal by combining the received FG signals; and
a drive control circuit configured to generate, based on a speed command signal indicating a target number of rotations of the motor, the drive control signal and output the drive control signal to each of the plurality of motor drive circuits,
wherein the FG signals output from the plurality of motor drive circuits have a phase difference from each other.

2. The motor drive control device according to claim 1 ,
wherein the plurality of motor drive circuits include
a first motor drive circuit configured to perform, based on the drive control signal, control of energization of the motor and output a first FG signal having a frequency corresponding to the actual number of rotations of the motor, and
a second motor drive circuit configured to perform, based on the drive control signal, control of energization of the motor and output a second FG signal having the frequency corresponding to the actual number of rotations of the motor and being out of phase with the first FG signal, and
the composite signal generation circuit combines the first FG signal and the second FG signal to generate the composite signal.

3. The motor drive control device according to claim 2 ,
wherein the first FG signal and the second FG signal are rectangular-wave shaped signals having a predetermined duty ratio, and
the composite signal generation circuit generates, based on a logical AND of the first FG signal and the second FG signal, the composite signal.

4. The motor drive control device according to claim 3 ,
wherein the first motor drive circuit includes a first output terminal configured to output the first FG signal and a first output transistor connected between the first output terminal and a first fixed potential,
the second motor drive circuit includes a second output terminal configured to output the second FG signal and a second output transistor connected between the second output terminal and the first fixed potential, and
the composite signal generation circuit includes a load connected between a connection point where the first output terminal and the second output terminal are commonly connected and a second fixed potential different from the first fixed potential.

5. The motor drive control device according to claim 3 ,
wherein the drive control circuit receives an input of the composite signal and determines, when the composite signal is a signal having a duty ratio according to a phase difference between the first FG signal and the second FG signal, that the motor drives normally.

6. The motor drive control device according to claim 5 ,
wherein the drive control circuit receives the input of the composite signal and determines, when the composite signal has the predetermined duty ratio, that either the first motor drive circuit or the second motor drive circuit has an open-circuit failure.

7. The motor drive control device according to claim 5 ,
wherein the drive control circuit receives the input of the composite signal and determines, when the composite signal has a predetermined logical value, that at least one of the first motor drive circuit or the second motor drive circuit has a short-circuit failure or that the motor is in a locked state.

8. The motor drive control device according to claim 2 ,
wherein the first motor drive circuit outputs a first lock detection signal being a binary signal and indicating whether the motor is in a locked state,
the second motor drive circuit outputs a second lock detection signal being a binary signal and indicating whether the motor is in the locked state, and
the composite signal generation circuit combines the first FG signal, the second FG signal, the first lock detection signal, and the second lock detection signal to generate the composite signal.

9. The motor drive control device according to claim 8 ,
wherein the first FG signal and the second FG signal are rectangular-wave shaped signals having a predetermined duty ratio, and
the composite signal generation circuit generates, based on a logical AND of a signal based on a logical AND of the first FG signal and the second FG signal and a signal based on a logical AND of the first lock detection signal and the second lock detection signal, the composite signal.

10. The motor drive control device according to claim 9 ,
wherein the first motor drive circuit includes a first output terminal configured to output the first FG signal, a second output terminal configured to output the first lock detection signal, a first output transistor connected between the first output terminal and a first fixed potential, and a second output transistor connected between the second output terminal and the first fixed potential,
the second motor drive circuit includes a third output terminal configured to output the second FG signal, a fourth output terminal configured to output the second lock detection signal, a third output transistor connected between the third output terminal and the first fixed potential, and a fourth output transistor connected between the fourth output terminal and the first fixed potential, and
the composite signal generation circuit includes
a first load connected between a first connection point where the first output terminal and the third output terminal are commonly connected and a second fixed potential different from the first fixed potential,
a second load connected between a second connection point where the second output terminal and the fourth output terminal are commonly connected and the second fixed potential,
a third load including one end connected to the second fixed potential,
a first switch element connected between the first fixed potential and another end of the third load and controlled, based on a voltage at the first connection point, to on or off, and
a second switch element connected between the first fixed potential and the other end of the third load and controlled, based on a voltage at the second connection point, to on or off.

11. The motor drive control device according to claim 9 ,
wherein the drive control circuit determines, when the composite signal has a duty ratio according to a phase difference between the first FG signal and the second FG signal, that the motor is being driven normally.

12. The motor drive control device according to claim 11 ,
wherein the drive control circuit determines, when the composite signal has the predetermined duty ratio, that either the first motor drive circuit or the second motor drive circuit has an open-circuit failure.

13. The motor drive control device according to claim 12 ,
wherein the drive control circuit determines, when the composite signal is at a first logical level, that either the first motor drive circuit or the second motor drive circuit has a short-circuit failure.

14. The motor drive control device according to claim 13 ,
wherein the drive control circuit determines, when the composite signal is at a second logical level different from the first logical level, that the motor is in a locked state.

15. A fan comprising:
the motor driv

Assignees

• Minebea Mitsumi Inc

Inventors

• Hisatomi Yuuya
• Tamitsuji Toshihiro
• Hijikata Hidetoshi

Classifications

• H02P6/17 Primary

  and for generating speed information · CPC title

• H02P25/04

  Single phase motors, e.g. capacitor motors · CPC title

• H02P29/024

  Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load · CPC title

• H03K19/20 Primary

  characterised by logic function, e.g. AND, OR, NOR, NOT circuits (H03K19/003 - H03K19/01 take precedence) · CPC title

• H02P29/028

  the motor continuing operation despite the fault condition, e.g. eliminating, compensating for or remedying the fault · CPC title