Motor control device

Patent metadata

Field	Value
Publication number	US-9929687-B2
Application number	US-201515315044-A
Country	US
Kind code	B2
Filing date	Oct 8, 2015
Priority date	Oct 17, 2014
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

A motor control device includes: a motor; an inverter; and a control device. The control device includes: a detection device detecting a rotational position and a revolution speed of the motor; a positioning control device for a rotor; a deceleration device for the motor; and a determination device for the revolution speed of the motor. When the revolution speed is higher than or equal to the first predetermined revolution speed, the motor control device starts controlling the motor to rotate at the target speed, according to the rotational position, without executing the positioning control. When the revolution speed is lower than the first predetermined revolution speed and higher than or equal to the second predetermined revolution speed, the deceleration device decelerates the motor. When the revolution speed is lower than the second predetermined revolution speed, the positioning control device starts executing the positioning control.

First claim

The invention claimed is:

1. A motor control device comprising:
a motor including a plurality of energization phases;
an inverter that individually controls energization of each of the energization phases for the motor; and
an integrated circuit that controls a rotation of the motor via the inverter, wherein:
the integrated circuit acts as:
a sensor-less detection device that detects a rotational position and a revolution speed of the motor;
a positioning control device that positions a rotor at a predetermined position by energizing a predetermined energization phase of the motor;
a deceleration device that decelerates the motor by short-circuiting a plurality of energization phases of the motor via the inverter; and
a determination device that determines whether the revolution speed of the motor detected by the detection device is higher than or equal to a first predetermined revolution speed or a second predetermined revolution speed, when rotating the motor at a predetermined target speed, the first predetermined revolution speed ensuring a predetermined accuracy of the rotational position for the detection device, and the second predetermined revolution speed, being used in determining whether a positioning control of the positioning control device is executed, is lower than the first predetermined revolution speed;

the motor control device starts controlling the motor to rotate at the target speed, according to the rotational position of the motor detected by the detection device, without executing the positioning control in the positioning control device when the determination device determines that the revolution speed of the motor is higher than or equal to the first predetermined revolution speed;
the motor control device controls the deceleration device to decelerate the motor when the determination device determines that the revolution speed of the motor is lower than the first predetermined revolution speed and higher than or equal to the second predetermined revolution speed; and
the motor control device controls the positioning control device to start executing the positioning control when the determination device determines that the revolution speed of the motor is lower than the second predetermined revolution speed.

2. The motor control device according to claim 1 , wherein:
the deceleration device decelerates the motor by short-circuiting intermittently the plurality of energization phases of the motor via the inverter; and
the detection device detects the rotational position and a numerical number of revolutions of the motor based on a current or a voltage generated from each energization phase of the motor when the deceleration device stops short-circuiting.

3. The motor control device according to claim 2 , wherein:
the second predetermined revolution speed is set to be lower than or equal to a revolution speed that prevents a demagnetizing current from flowing through the motor even when the positioning control device executes the positioning control.

4. The motor control device according to claim 1 , wherein:
the motor drives a fan; and
the control device controls the deceleration device to decelerate the motor when the fan rotates due to a wind hitting the fan.

5. The motor control device according to claim 1 , wherein:
the inverter comprises a plurality of switching devices, each switching device connected in parallel to a respective freewheeling diode;
the deceleration device periodically turns on and off a part of the switching devices in order to decelerate the motor;
when turning on the part of the switching devices, the plurality of energization phases of the motor short-circuit, and the motor decelerates; and
when turning off the part of the switching devices, a current flows into an electric storage device connected to the inverter through the freewheeling diode, and an electric power is regenerated.

6. The motor control device according to claim 5 , wherein:
the part of the switching devices, which the deceleration device periodically turns on and off, is a switching device connected to a low side of the switching devices for providing the inverter.

7. The motor control device according to claim 6 , wherein:
the detection device includes a comparison device that compares a neutral potential for the plurality of energization phases of the motor with a voltage applied to each energization phase; and
the detection device detects the rotational position and the revolution speed of the motor based on a combination of comparison results in the comparison device.

8. The motor control device according to claim 7 , wherein:
the detection device acquires a comparison result from the comparison device after a predetermined time has elapsed from when the part of the switching devices turns off.

9. The motor control device according to claim 5 , wherein:
the part of the switching devices, which the deceleration device periodically turns on and off, is a switching device connected to a high side of the switching devices for providing the inverter.

10. The motor control device according to claim 1 , wherein:
the positioning control places the rotor at a predetermined initial position and performs forced commutation thereby rotating the rotor from the predetermined initial position.

Assignees

• Denso Corp

Inventors

• Yoneshima Hiroko

Classifications

• H02P7/00

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

• G05B19/00

  Program-control systems · CPC title

• G05B13/00

  Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion (G05B19/00 takes precedence) · CPC title

• H02P23/04 Primary

  specially adapted for damping motor oscillations, e.g. for reducing hunting · CPC title

• H02P6/18 Primary

  without separate position detecting elements · CPC title