Motor control device

Patent metadata

Field	Value
Publication number	US-9847746-B2
Application number	US-201615237907-A
Country	US
Kind code	B2
Filing date	Aug 16, 2016
Priority date	Sep 10, 2015
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A motor control device is provided with a control circuit and a driving circuit. The control circuit switches over a current supply phase of the motor in a predetermined angular rotation of the rotor a first switching number of times in an acceleration range. The control circuit switches over the current supply phase of the motor in the predetermined angular rotation of the rotor a second switching number of times in a stationary rotation range in a specific condition that the rotation speed of the rotor is between a predetermined first threshold value and a predetermined second threshold value. The control circuit sets the second switching number to be smaller than the first switching number. In the acceleration range, the switching number is relatively large and hence a sufficient driving torque is applied to the rotor. In the stationary rotation range, the switching number is relatively small and hence the control circuit 61 needs to operate less, a current supply period for the motor is shortened and heat generation is suppressed.

First claim

What is claimed is:

1. A motor control device for an operation system, which is provided with a motor, an encoder for outputting a pulse signal in synchronization with a rotation of a rotor of the motor, the motor control device comprising:
a control circuit for determining a current supply phase of the motor based on the pulse signal outputted from the encoder; and
a driving circuit for rotationally driving the rotor to a target rotation position by switching over the current supply phase in response to a command of the control circuit, wherein
the control circuit is configured to switch over a current supply phase of the motor in a predetermined angular rotation of the rotor to cause the driving circuit to rotationally drive the rotor,
the control circuit is configured to switch over the current supply phase of the motor in the predetermined angular rotation of the rotor a first switching number of times in an acceleration range using a normal current supply map, which is from a start of rotational driving of the rotor to attainment of a rotation speed of the rotor to a predetermined first threshold value, and in a deceleration range, which is from a start of decreasing the rotation speed of the rotor toward a stop at a target rotation position to the stop of the rotor at the target rotation position,
the control circuit is configured to switch over the current supply phase of the motor in the predetermined angular rotation of the rotor a second switching number of times in a stationary rotation range between the acceleration range and the deceleration range using a low-switching current supply current supply map and in a specific condition that the rotation speed of the rotor is between the first threshold value and a predetermined second threshold value,
the control circuit is configured to set the second switching number to be smaller than the first switching number, and
the control circuit is configured to determine the current supply phase by selectively using current supply maps including the normal current supply map and the low-switching current supply map.

2. The motor control device according to claim 1 , wherein:
the control circuit is configured to set the second switching number to be equal to or smaller than one half of the first switching number.

3. The motor control device according to claim 2 , wherein:
the control circuit is configured to set the second switching number to 0.

4. The motor control device according to claim 3 , wherein:
the control circuit is configured to switch over a current supply mode between a one-phase current supply, in which a current is supplied to only one of plural phase coils of the motor, and a two-phase current supply, in which the current is supplied to any two of the plural phase coils of the motor, in the acceleration range; and
the control circuit is configured to prohibit the current from being supplied to the motor in an entire period of the predetermined angular rotation of the rotor when the rotor is in the specific condition.

5. The motor control device according to claim 2 , wherein:
the control circuit is configured to switch over a current supply mode between a one-phase current supply, in which a current is supplied to only one of plural phase coils of the motor, and a two-phase current supply, in which the current is supplied to any two of the plural phase coils of the motor, in the acceleration range; and
the control circuit is configured to switch over the current supply mode between the two-phase current supply and no-current supply when the rotor is in the specific condition.

6. The motor control device according to claim 2 , wherein:
the control circuit is configured to switch over a current supply mode between a one-phase current supply, in which a current is supplied to only one of plural phase coils of the motor, and a two-phase current supply, in which the current is supplied to any two of the plural phase coils of the motor, in the acceleration range; and
the control circuit switches over the current supply mode between the one-phase current supply and no-current supply when the rotor is in the specific condition.

7. The motor control device according to claim 2 , wherein:
the control circuit is configured to control to supply a current to all of plural phase coils of the motor in the acceleration range; and
the control circuit is configured to control current supply to a part of the plural phase coils when the rotor is in the specific condition.

8. The motor control device according to claim 2 , wherein:
the control circuit is configured to switch over the current supply phase of the motor in the predetermined angular rotation of the rotor a third switching number of times in the stationary rotation range and in a condition that the rotation speed of the rotor is higher than the second threshold value; and
the control circuit is configured to set the third switching number to be larger than the second switching number.

9. The motor control device according to claim 8 , wherein:
the control circuit is configured to switch over the current supply phase of the motor in the predetermined angular rotation of the rotor a third switching number of times in the stationary rotation range and in a condition that the rotation speed of the rotor is higher than the second threshold value; and
the control circuit is configured to set the third switching number to be larger than the second switching number.

10. The motor control device according to claim 1 , wherein:
the control circuit is configured to set the second switching number to 0.

11. The motor control device according to claim 10 , wherein:
the control circuit is configured to switch over a current supply mode between a one-phase current supply, in which a current is supplied to only one of plural phase coils of the motor, and a two-phase current supply, in which the current is supplied to any two of the plural phase coils of the motor, in the acceleration range; and
the control circuit is configured to prohibit the current from being supplied to the motor in an entire period of the predetermined angular rotation of the rotor when the rotor is in the specific condition.

12. The motor control device according to claim 1 , wherein:
the control circuit is configured to switch over a current supply mode between a one-phase current supply, in which a current is supplied to only one of plural phase coils of the motor, and a two-phase current supply, in which the current is supplied to any two of the plural phase coils of the motor, in the acceleration range; and
the control circuit is configured to switch over the current supply mode between the two-phase current supply and no-current supply when the rotor is in the specific condition.

13. The motor control device according to claim 1 , wherein:
the control circuit is configured to switch over a current supply mode between a one-phase current supply, in which a current is supplied to only one of plural phase coils of the motor, and a two-phase current supply, in which the current is supplied to any two of the plural phase coils of the motor, in the acceleration range; and
the control circuit switches over the current supply mode between the one-phase current supply and no-current supply when the rotor is in the specific condition.

14. The motor control device according to claim 1 , wherein:
the control circuit is configured to control to supply a current to all of plural phase coils of the motor in the acceleration range; and
the control circuit is configured to control current supply to a part of the plural phase coils when

Assignees

• Denso Corp

Inventors

• Yoshida Kazuhiro
• Nakayama Seiji

Classifications

• H02P25/08

  Reluctance motors · CPC title

• H02P23/20 Primary

  Controlling the acceleration or deceleration · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• F16H61/28

  with at least one movement of the final actuating mechanism being caused by a non-mechanical force, e.g. power-assisted · CPC title

• F16H2061/2823

  Controlling actuator force way characteristic, i.e. controlling force or movement depending on the actuator position, e.g. for adapting force to synchronisation and engagement of gear clutch · CPC title