Motor driving device having lock protection mode

Patent metadata

Field	Value
Publication number	US-11088641-B2
Application number	US-201916720563-A
Country	US
Kind code	B2
Filing date	Dec 19, 2019
Priority date	Sep 11, 2019
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A motor driving device having a lock protection mode includes a rotation speed detecting unit, an operating unit, a driving unit, a floating point selecting unit, a BEMF detecting unit, a control unit, and a lock protection unit. The operating unit enters an operating mode after a motor is stably operated, and generates an operating signal having phases according to a commutation sequence, and the driving unit drives the motor. The BEMF detecting unit detects a BEMF of a first floating phase to generate a detection result. The control unit outputs a commutation signal to cause the driving unit to drive the motor. When the rotation speed detecting unit determines that a rotation speed of the motor exceeds a predetermined rotation speed, the rotation speed detecting unit outputs a switching signal to the lock protection unit to enter the lock protection mode.

First claim

What is claimed is:

1. A motor driving device having a lock protection mode for driving a motor, comprising:
a rotation speed detecting unit configured to detect a rotation speed of the motor;
an operating unit configured to enter an operating mode after the rotation speed detecting unit detects that the motor is continuously rotated at the rotation speed, wherein the operating unit generates an operating signal having a plurality of phases according to a commutation sequence, and the commutation sequence is set according to a predetermined rotation direction of the motor;
a driving unit coupled to the operating unit and the motor and configured to drive the motor with the plurality of phases;
a floating point selecting unit coupled to the driving unit and the motor, and configured to select a first phase circuit of the motor as a first floating phase in the operating mode;
a back electromotive force (BEMF) detecting unit coupled to the floating point selecting unit and configured to detect whether a back electromotive force (BEMF) of the first floating phase has a first voltage level or a second voltage level to generate a detection result;
a control unit coupled to the BEMF detecting unit and the driving unit and configured to output a commutation signal to the driving unit according to the detection result, thereby causing the driving unit to drive the motor according to the commutation sequence and the commutation signal; and
a lock protection unit configured to control the driving unit to enter the lock protection mode in response to receiving a switching signal;
wherein the rotation speed detecting unit is configured to determine whether the rotation speed of the motor exceeds a predetermined rotation speed; and the rotation speed detecting unit is configured to output, in response to the rotation speed of the motor exceeding the predetermined rotation speed, the switching signal to the lock protection unit, causing the driving unit to enter the lock protection mode, or control the floating point selecting unit to select the first phase circuit and a second phase circuit of the motor as the first floating phase and a second floating phase; and the BEMF detecting unit is configured to detect the BEMFs of the first floating phase and the second floating phase to determine whether to output the switching signal to the lock protection unit to cause the driving unit to enter the lock protection mode, and
wherein in the lock protection mode, the driving unit repeatedly drives and stops the motor.

2. The motor driving device according to claim 1 , wherein the BEMF detecting unit is configured to detect, in response to the rotation speed detecting unit determining that the rotation speed of the motor exceeds the predetermined rotation speed, whether the BEMFs of the first floating phase and the second floating phase have the first voltage level or the second voltage level corresponding to the commutation sequence, and the BEMF detecting unit is configured to, in response to the BEMFs of the first floating phase and the second floating phase not having the first voltage level or the second voltage level corresponding to the commutation sequence, determine to output the switching signal to the lock protection unit to cause the driving unit to enter the lock protection mode.

3. The motor starting device according to claim 1 , wherein the BEMF detecting unit includes a hysteresis comparator configured to detect whether the BEMF of the first floating phase or the second floating phase is greater than a positive value of a hysteresis voltage or less than a negative value of the hysteresis voltage to generate a high voltage level or a low voltage level.

4. The motor driving device according to claim 2 , wherein the control unit is configured to set a hysteresis comparator to the first voltage level according to the commutation sequence of the plurality of phases to determine whether the BEMF of the first floating phase or the second floating phase is smaller than a negative value of a hysteresis voltage; or the control unit is configured to set the hysteresis comparator to the second voltage level to determine whether the BEMF of the first floating phase or the second floating phase is greater than a positive value of the hysteresis voltage.

5. The motor driving device according to claim 3 , wherein when the hysteresis comparator is set to the first voltage level and configured to determine whether the BEMF of the first floating phase or the second floating phase is less than the negative value of the hysteresis voltage, if the BEMF of the first floating phase or the second floating phase is determined to be less than the negative value of the hysteresis voltage, the hysteresis comparator is configured to generate the low voltage level.

6. The motor driving device according to claim 4 , wherein when the hysteresis comparator is set to the second voltage level and configured to determine whether the BEMF of the first floating phase or the second floating phase is greater than the positive value of the hysteresis voltage, if the BEMF of the first floating phase or the second floating phase is determined to be greater than the positive value of the hysteresis voltage, the hysteresis comparator is configured to generate the high voltage level.

7. A motor driving device having a lock protection mode for driving a motor, comprising:
a rotation speed detecting unit configured to detect a rotation speed of the motor;
an operating unit configured to enter an operating mode after the rotation speed detecting unit detects that the motor is continuously rotated at the rotation speed, wherein the operating unit generates an operating signal having a plurality of phases according to a commutation sequence, and the commutation sequence is set according to a predetermined rotation direction of the motor;
a driving unit coupled to the operating unit and the motor and configured to drive the motor with the plurality of phases;
a floating point selecting unit coupled to the driving unit and the motor, and configured to select a first phase circuit of the motor as a first floating phase in the operating mode;
a back electromotive force (BEMF) detecting unit coupled to the floating point selecting unit and configured to detect whether a back electromotive force (BEMF) of the first floating phase has a first voltage level or a second voltage level to generate a detection result;
a control unit coupled to the BEMF detecting unit and the driving unit and configured to output a commutation signal to the driving unit according to the detection result, thereby causing the driving unit to drive the motor according to the commutation sequence and the commutation signal, wherein the control unit is configured to control the BEMF detecting unit to detect the BEMF of the first floating phase after the commutation signal is generated and a mask time elapses;
a lock protection unit configured to control the driving unit to enter the lock protection mode in response to receiving a switching signal; and
a counting unit configured to:
increase a count value when the BEMF detecting unit detects that the commutation signal is generated within a predetermined time after the mask time elapses; and
output the switching signal to the lock protection unit in response to the count value being added to a predetermined value to cause the driving unit to enter the lock protection mode, or control the floating point selecting unit to select the first phase circuit and a second phase circuit of the motor as the first floating phase and a second floating phase,
wherein the BEMF detecting unit is configured to detect the BEMFs of the first floating phase and the second floating phase to determine whether to output the switching sign

Assignees

• Anpec Electronics Corp

Inventors

• Chen Kun-Min

Classifications

• H02P6/182 Primary

  using back-emf in windings · CPC title

• H02P29/02

  Providing protection against overload without automatic interruption of supply (protection against faults of stepper motors H02P8/36) · CPC title

• H02P6/06 Primary

  Arrangements for speed regulation of a single motor wherein the motor speed is measured and compared with a given physical value so as to adjust the motor speed · CPC title

• H02P7/00

  Arrangements for regulating or controlling the speed or torque of electric DC motors · CPC title

• H02P3/025

  holding the rotor in a fixed position after deceleration · CPC title