MOTOR CONTROL DEVICE

• US 20160056692A1
• Filed: 08/20/2015
• Published: 02/25/2016
• Est. Priority Date: 08/21/2014
• Status: Active Application

• Current Assignee: DENSO Corporation
• Original Assignee: ASMO Company Limited (DENSO Corporation)
• Inventors: SUZUKI, Hidenobu
• Granted Patent: US 10,284,054 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02K 11/215 Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02K 29/12 using detecting coils using the machine windings as detecting coil

Abstract

A motor control device is provided that enables smooth rotation control from a low-speed region to a high-speed region. A microcomputer of the motor control device calculates the rotation speed of a rotor from the time between edges that appear per 60° electrical angle at the time of starting the motor, from a signal that is output when a the hall sensor detects the magnetic field of a rotating rotor and, in conjunction with an increase in the rotation speed of the rotor, calculates the rotation speed of a rotor from the time between edges that appear at electrical angles that are larger than the electrical angle 60° in the signal, per 180° electrical angle, per 360° electrical angle, per 900° electrical angle, and per 1800° electrical angle.

Claims

1. A motor control device, comprising:

a magnetic field detection section that detects a magnetic field of a permanent magnet rotating together with an output shaft of a motor, and that outputs a signal which is a rectangular wave in which an edge appears per a predetermined number of degrees of electrical angle in accordance with a change in the magnetic field; and

a control section that calculates a rotation speed of the output shaft based on a time between adjacent edges in the signal at a time of starting of the motor, and that calculates the rotation speed of the output shaft based on a time between edges that appear in the signal per an electrical angle which is larger than the predetermined number of degrees of electrical angle when the rotation speed of the output shaft increases.

2. The motor control device of claim 1, wherein the control section calculates the rotation speed of the output shaft based on a time between edges that appear in the signal per a first electrical angle which is larger than the predetermined number of degrees of electrical angle when the rotation speed of the output shaft is a first rotation speed, and that calculates the rotation speed of the output shaft based on a time between edges that appear in the signal per a second electrical angle which is larger than the first electrical angle when the rotation speed of the output shaft is a second rotation speed which is larger than the first rotation speed.

3. The motor control device of claim 2, wherein the second electrical angle is an electrical angle that corresponds to one rotation of the output shaft, and the first electrical angle has a size that is between the predetermined number of degrees of electrical angle and the second electrical angle.

4. The motor control device of claim 3, wherein the first electrical angle has a size that is an integral multiple of the predetermined number of degrees of electrical angle.

5. The motor control device of claim 1, wherein:

the motor is a brushless DC motor, and

three of the magnetic field detection sections are provided, respectively corresponding to a U phase, a V phase and a W phase of the brushless DC motor.

6. The motor control device of claim 2, wherein:

the motor is a brushless DC motor, and

three of the magnetic field detection sections are provided, respectively corresponding to a U phase, a V phase and a W phase of the brushless DC motor.

7. The motor control device of claim 3, wherein:

the motor is a brushless DC motor, and

three of the magnetic field detection sections are provided, respectively corresponding to a U phase, a V phase and a W phase of the brushless DC motor.

8. The motor control device of claim 4, wherein:

the motor is a brushless DC motor, and

three of the magnetic field detection sections are provided, respectively corresponding to a U phase, a V phase and a W phase of the brushless DC motor.