Motor control circuit, motor drive control device, and motor unit

Patent metadata

Field	Value
Publication number	US-11539321-B2
Application number	US-202117470267-A
Country	US
Kind code	B2
Filing date	Sep 9, 2021
Priority date	Sep 23, 2020
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

The degree of flexibility of a speed curve for a target rotational speed of a motor is to be increased. A motor control circuit 11 measures a duty cycle of an input speed command signal Sc indicating a target rotational speed of a motor 50 to be driven, sets an inflection point In for each duty cycle obtained by equally dividing a possible duty cycle range assumed by the speed command signal Sc based on resolution information 301 indicating a resolution of the duty cycle of the speed command signal Sc, calculates a rotational speed corresponding to the measured duty cycle of the speed command signal Sc based on rotational speed information 302 indicating rotational speeds at the inflection points In on a speed curve and the set inflection points In, and determines the calculated rotational speed as the target rotational speed.

First claim

What is claimed is:

1. A motor control circuit comprising:
a speed command analyzing unit measuring a duty cycle of an input speed command signal indicating a target rotational speed of a motor to be driven;
a storage unit storing parameter information for defining a speed curve indicating a relationship between the duty cycle of the speed command signal and the target rotational speed;
a target rotational speed determining unit determining the target rotational speed based on the parameter information stored in the storage unit and a result of measurement of the duty cycle of the speed command signal by the speed command analyzing unit; and
a drive control signal generating unit generating a drive control signal for controlling driving of the motor based on the target rotational speed determined by the target rotational speed determining unit, wherein
the parameter information includes resolution information indicating a resolution of the duty cycle of the speed command signal and rotational speed information indicating a rotational speed at an inflection point on the speed curve, and
the target rotational speed determining unit sets the inflection point for each duty cycle obtained by equally dividing a possible duty cycle range assumed by the speed command signal based on the resolution information, calculates a rotational speed corresponding to the duty cycle of the speed command signal measured by the speed command analyzing unit based on the set inflection point and the rotational speed information, and determines the calculated rotational speed as the target rotational speed.

2. The motor control circuit according to claim 1 , wherein
the storage unit is configured to be capable of rewriting the parameter information.

3. The motor control circuit according to claim 1 , wherein
the resolution information includes information on a number of inflection points provided at constant intervals on the speed curve,
the speed command analyzing unit measures the duty cycle of the speed command signal with a resolution based on the number of inflection points, and
the target rotational speed determining unit identifies an inflection point corresponding to the duty cycle of the speed command signal measured by the speed command analyzing unit from among the set inflection points, calculates a rotational speed at the identified inflection point based on the rotational speed information, and determines the calculated rotational speed as the target rotational speed.

4. The motor control circuit according to claim 1 , wherein
the resolution information includes at least two of information on a number of inflection points as a first resolution of the duty cycle of the speed command signal, information on a speed command number as a second resolution of the duty cycle of the speed command signal, the second resolution being higher than the first resolution, and information on a number of linear interpolation points provided at constant intervals between the adjacent inflection points for interpolation between the inflection points with straight lines,
the target rotational speed determining unit sets the inflection point for each duty cycle obtained by equally dividing a possible duty cycle range assumed by the speed command signal based on the number of inflection points and sets a speed command sequence number for each duty cycle obtained by equally dividing the possible duty cycle range assumed by the speed command signal based on the speed command number, and identifies the speed command sequence number corresponding to the duty cycle of the speed command signal measured by the speed command analyzing unit from among the set speed command sequence numbers, and
the target rotational speed determining unit calculates an increase in rotational speed between the linear interpolation points present between the inflection point immediately prior to the identified speed command sequence number and the inflection point immediately subsequent to the identified speed command sequence number based on a difference between a rotational speed at the immediately prior inflection point and a rotational speed at the immediately subsequent inflection point, calculates a rotational speed corresponding to the identified speed command sequence number based on a value of the calculated increase in rotational speed between the linear interpolation points and the number of linear interpolation points, and determines the calculated rotational speed as the target rotational speed.

5. The motor control circuit according to claim 4 , wherein
the target rotational speed determining unit multiplies, by the increase in rotational speed between the linear interpolation points, a value of a remainder obtained by dividing the identified speed command sequence number by a number equal to the number of linear interpolation points plus 1, adds the rotational speed at the immediately prior inflection point to the value obtained by the multiplication, and determines the value obtained by the addition as the target rotational speed.

6. The motor control circuit according to claim 4 , wherein
when n is defined as an integer larger than or equal to 1, the number of linear interpolation points is (2 n −1).

7. The motor control circuit according to claim 4 , wherein
the target rotational speed determining unit calculates the number of linear interpolation points based on the information on the number of inflection points and the information on the speed command number.

8. A motor drive control device comprising:
the motor control circuit according to claim 1 ; and
a motor drive circuit driving the motor based on the drive control signal generated by the motor control circuit.

9. A motor unit comprising:
the motor drive control device according to claim 8 ; and
the motor driven by the motor drive control device.

Assignees

• Minebea Mitsumi Inc

Inventors

• Kaidu Hiroyuki
• Aoki Masato
• Suzuki Takahiro
• Sakuma Tomotaka
• Okabuchi Yoshihisa

Classifications

• G05B15/02

  electric · CPC title

• H02P27/08 Primary

  with pulse width modulation · CPC title

• H02P6/08 Primary

  Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence) · CPC title