Motor drive circuit, method for detecting single phase DC motor rotation direction and method for starting motor

Patent metadata

Field	Value
Publication number	US-9973118-B2
Application number	US-201514831461-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Sep 22, 2014
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A motor drive circuit including a back electromotive force detecting module and a processing module is disclosed herein. The back electromotive force detecting module is electrically connected to a single phase DC motor and is configured to detect a back electromotive force of the single phase DC motor and to output a detecting signal correspondingly. The processing module is electrically connected to the back electromotive force detecting module and the single phase DC motor. The processing module is configured to determine the rotation direction of the single phase DC motor according to the detecting signal and a hall signal outputted by a hall element located in the single phase DC motor, and is configured to control the single phase DC motor.

First claim

What is claimed is:

1. A motor drive circuit, comprising:
a back electromotive force detecting module electrically connected to a single phase dc motor, and configured to detect a first back electromotive force of the single phase dc motor and to output a first detecting signal correspondingly; and
a processing module electrically connected to the back electromotive force detecting module and the single phase dc motor, and configured to determine a rotation direction of the single phase dc motor according to the first detecting signal, a reference level, and a hall signal outputted by a hall element disposed in the single phase dc motor, and to control the single phase dc motor,
wherein the back electromotive force detecting module comprises:
an input terminal electrically connected to the single phase dc motor;
an output terminal electrically connected to the processing module, and configured to output the first detecting signal;
a first diode comprising:
a first terminal electrically connected to the input terminal of the back electromotive force detecting module; and
a second terminal;

a first resistor unit comprising:
a first terminal electrically connected to the second terminal of the first diode; and
a second terminal electrically connected to the output terminal of the back electromotive force detecting module; and

a second resistor unit comprising:
a first terminal electrically connected to the second terminal of the first resistor unit; and
a second terminal electrically connected to a voltage source.

2. The motor drive circuit of claim 1 , wherein the first detecting signal outputted by the back electromotive force detecting module has a first level corresponding to the first back electromotive force when the first back electromotive force is positive; and
the first detecting signal outputted by the back electromotive force detecting module has a second level corresponding to the first back electromotive force when the first back electromotive force is negative.

3. The motor drive circuit of claim 1 , wherein the back electromotive force detecting module comprises:
a comparator configured to compare a reference voltage signal with a back electromotive force signal representing the first back electromotive force, and to output the first detecting signal with a corresponding level accordingly.

4. The motor drive circuit of claim 1 , wherein the processing module comprises:
a control unit, wherein when the hall signal outputted by the hall element has a detecting level, the control unit is configured to compare the first detecting signal with the reference level;
wherein when the level of the first detecting signal is higher than the reference level, the rotation direction of the single phase dc motor is determined to be forward, and when the level of the first detecting signal is lower than the reference level, the rotation direction of the single phase dc motor is determined to be reverse.

5. The motor drive circuit of claim 4 , wherein the processing module further comprises:
a driving unit controlled by the control unit and configured to drive the single phase dc motor selectively according to the rotation direction of the single phase dc motor.

6. A motor drive circuit, comprising:
a back electromotive force detecting module electrically connected to a single phase dc motor, and configured to detect a first back electromotive force of the single phase dc motor and to output a first detecting signal correspondingly; and
a processing module electrically connected to the back electromotive force detecting module and the single phase dc motor, and configured to determine a rotation direction of the single phase dc motor according to the first detecting signal, a reference level, and a hall signal outputted by a hall element disposed in the single phase dc motor, and to control the single phase dc motor,
wherein
the back electromotive force detecting module is further configured to detect a second back electromotive force of the single phase dc motor and to output a second detecting signal correspondingly;
the processing module is further configured to determine the rotation direction of the single phase dc motor according to the second detecting signal and to control the single phase dc motor, and
the back electromotive force detecting module comprises:
a first input terminal electrically connected to the single phase dc motor, and configured to detect the first back electromotive force;
a second input terminal electrically connected to the single phase dc motor, and configured to detect the second back electromotive force;
a first output terminal electrically connected to the processing module, and configured to output the first detecting signal;
a second output terminal electrically connected to the processing module, and configured to output the second detecting signal;
a first diode comprising:
a first terminal electrically connected to the first input terminal of the back electromotive force detecting module; and
a second terminal;

a first resistor unit comprising:
a first terminal electrically connected to the second terminal of the first diode; and
a second terminal electrically connected to the first output terminal of the back electromotive force detecting module;

a second resistor unit comprising:
a first terminal electrically connected to the second terminal of the first resistor unit; and
a second terminal electrically connected to a voltage source;

a second diode comprising:
a first terminal electrically connected to the second input terminal of the back electromotive force detecting module; and
a second terminal;

a third resistor unit comprising:
a first terminal electrically connected to the second terminal of the second diode; and
a second terminal electrically connected to the second output terminal of the back electromotive force detecting module; and

a fourth resistor unit comprising:
a first terminal electrically connected to the second terminal of the third resistor unit; and
a second terminal electrically connected to the voltage source.

7. The motor drive circuit of claim 6 , wherein the processing module comprises:
a control unit, wherein when the hall signal outputted by the hall element has a detecting level, the control unit is configured to compare the first detecting signal and the second detecting signal with the reference level to determine the rotation direction of the single phase dc motor.

8. A method for determining a rotation direction of a single phase dc motor comprising:
detecting a first back electromotive force of the single phase dc motor and outputting a first detecting signal correspondingly;
receiving a hall signal outputted by a hall element disposed in the single phase dc motor;
determining the rotation direction of the single phase dc motor according to the first detecting signal and the hall signal;
determining whether the single phase dc motor is dynamic according to the hall signal;
when the single phase dc motor is determined to be stationary, activating the single phase dc motor directly;
when the single phase dc motor is determined to be dynamic, determining the rotation direction of the single phase dc motor according to the first detecting signal and the hall signal, the first detecting signal corresponding to the first back electromotive force of the single phase dc motor; and
controlling the single phase dc motor according to the rotation direction of the single phase dc motor,
wherein controlling the single phase dc motor comprises:
when the rotation direction of the single phase dc motor is determined to be forward, activating the single phase dc motor directly;
when the rotation direction of t

Assignees

• Delta Electronics Inc

Inventors

• Lin Yu-Liang
• Tang Chung-Hung
• Liu Cheng-Chieh
• Lin Chien-Sheng
• Chiu Chun-Lung

Classifications

• H02P6/008 Primary

  Electricity · mapped topic

• G01D5/145

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title

• H02P6/182 Primary

  using back-emf in windings · CPC title

• H02P6/20

  Arrangements for starting (H02P6/08 takes precedence) · CPC title

• H02P6/26 Primary

  Arrangements for controlling single phase motors · CPC title