Device and control method for driving sensorless BLDC motor

Patent metadata

Field	Value
Publication number	US-10348226-B2
Application number	US-201615334045-A
Country	US
Kind code	B2
Filing date	Oct 25, 2016
Priority date	Nov 30, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A device and control method for driving a sensorless brushless DC (BLDC) motor, particularly related to a technology configured to increase the accuracy of detection of Zero Cross Point through a non-commutation period in a pulse width modulation (PWM) control. The device for driving a sensorless BLDC motor to switch a current applied to a stator winding based on a position of a rotor includes a three phase inverter configured to convert a DC input voltage into a three phase AC voltage and supply the three phase AC voltage to the BLDC motor; a terminal voltage detector configured to detect a three phase terminal voltage from an output terminal of the three phase inverter; and a controller configured to perform a PWM control of the terminal voltage based on a three phase back electromotive force (EMF) included in the detected terminal voltage. The PWM control includes a non-commutation control in which the switching of the current does not occur.

First claim

What is claimed is:

1. A device for driving a sensorless brushless DC (BLDC) motor to switch a current applied to a stator winding based on a position of a rotor, the device comprising:
a three phase inverter configured to convert a DC input voltage into a three phase AC voltage and supply the three phase AC voltage to the BLDC motor;
a terminal voltage detector configured to detect a three phase terminal voltage from an output terminal of the three phase inverter; and
a controller configured to:
perform a pulse width modulation (PWM) control of the terminal voltage based on a three phase back electromotive force (EMF) included in the detected terminal voltage, wherein the PWM control comprises a non-commutation control that generates no PWM signals in a predetermined time period prior to and after each of Zero Crossing Point (ZCP)s of three phase pulses.

2. The device of claim 1 , further comprising:
a Zero Crossing Point (ZCP) detector configured to detect a ZCP of the three phase back EMF based on a PWM signal generated by the PWM control of the terminal voltage.

3. The device of claim 2 , wherein the ZCP detector comprises a Zero Point (ZP) comparator configured to detect a ZCP of the three phase back EMF by comparing the detected three phase terminal voltage with an input voltage of the motor.

4. The device claim 3 , wherein the ZP comparator is configured to output a positive voltage in a period in which a difference between the three phase terminal voltage and the input voltage of the motor is positive, and output a Zero voltage in a period in which a difference
between the three phase terminal voltage and the input voltage of the motor is negative.

5. The device of claim 1 , wherein the controller is configured to perform a non-commutation control configured to generate a non-commutation signal period by removing a PWM signal for an operation of a switch switching the current.

6. The device of claim 2 , wherein the controller is configured to detect a position of the rotor of the motor based on the detected ZCP of the three phase back EMF, and control a switching operation of the three phase inverter based on the detected position of the rotor.

7. The device of claim 2 , wherein the ZCP detector is configured to detect a ZCP of the three phase back EMF based on a non-commutation signal period generated by the PWM control of the terminal voltage including the non-commutation control.

8. The device of claim 2 , further comprising:
a phase current converter configured to drive the three phase inverter by determining a position of the rotor included in the motor based on the detected ZCP of the three phase back EMF, and determining a commutation time of the motor based on the determined position of the rotor.

9. The device of claim 2 , further comprising:
a PWM signal generator configured to determine a switching pattern of a PWM signal based on the PWM control, and transmit the switching pattern to the three phase inverter.

10. The device of claim 9 , further comprising:
a pulse width modulator configured to change a rotation speed of the motor by changing a pulse width of the PWM signal.

11. A method for driving a sensorless brushless DC (BLDC) motor to switch a current applied to a stator winding based on a position of a rotor, the method comprising:
converting a DC input voltage into a three phase AC voltage and supplying the three phase AC voltage to the BLDC motor;
detecting a three phase terminal voltage from an output terminal of a three phase inverter;
performing a pulse width modulation (PWM) control of the terminal voltage including a non-commutation control that generates no PWM signals in a predetermined time period prior to and after each of Zero Crossing Point (ZCP)s of three phase pulses, based on a three phase back electromotive force (EMF) included in the detected terminal voltage; and
detecting a Zero Crossing Point (ZCP) of the three phase back EMF based on a PWM signal generated by the PWM control of the terminal voltage.

12. The method of claim 11 , wherein detecting the ZCP comprises detecting a ZCP of the three phase back EMF by comparing the detected three phase terminal voltage with the input voltage of the motor.

13. The method of claim 12 , wherein the detection of the ZCP outputs a positive voltage in a period in which a difference between the three phase terminal voltage and the input voltage of the motor is positive, and outputs a Zero voltage in a period in which a difference between the three phase terminal voltage and the input voltage of the motor is negative.

14. The method of claim 11 , wherein the non-commutation control generates a non-commutation signal period by removing a PWM signal for an operation of a switch switching the current.

15. The method of claim 11 , further comprising:
detecting a position of the rotor of the motor based on the detected ZCP of the three phase back EMF and controlling a switching operation of the three phase inverter based on the detected position of the rotor.

16. The method of claim 11 , wherein detecting the ZCP comprises detecting a ZCP of the three phase back EMF based on a non-commutation signal period generated from the PWM control of the terminal voltage including the non-commutation control.

17. The method of claim 11 , further comprising:
driving the three phase inverter by determining a position of the rotor included in the motor based on the detected ZCP of the three phase back EMF, and determining a commutation time of the motor based on the determined position of the rotor.

18. The method of claim 11 , further comprising:
determining a switching pattern of the PWM signal based on the PWM control and transmitting the switching pattern to the three phase inverter.

19. The method of claim 11 , further comprising:
changing a rotation speed of the motor by changing a pulse width of the PWM signal.

Assignees

• Samsung Electronics Co Ltd
• Industry Univ Cooperation Foundation Hanyang Univ Iucf Hyu

Inventors

• Park Young Jae
• Kim In Gun
• Hong Hyun Seok
• Kim Min Jae
• Kim Sin-Ae
• Sin Hyo Won
• Lee Ju

Classifications

• H02P6/157

  wherein the commutation is function of electro-magnetic force [EMF] · CPC title

• H02P27/08

  with pulse width modulation · CPC title

• H02P6/182 Primary

  using back-emf in windings · CPC title

• H02P6/187

  using the star point voltage · CPC title