Motor drive apparatus equipped with energy storage unit

• US 8,901,866 B2
• Filed: 05/15/2012
• Issued: 12/02/2014
• Est. Priority Date: 06/24/2011
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Sakai, Koujirou, Iwashita, Yasusuke
• Primary Examiner(s): Chan, Kawing
• Assistant Examiner(s): Carrasquillo, Jorge L
• Application Number:
  US13/471,542
• Publication Number:
  US 20120326641A1
• Time in Patent Office: 931 Days
• Field of Search: 318/795, 318/817, 318/150, 318/161, 318/400.31, 318/507, 318/130, 318/139, 307/48, 307/60, 307/65, 307/66, 307/9.1, 307/64, 320/101, 320/134, 320/128, 363/37, 363/34, 363/65
• US Class Current: 318/400.31
• CPC Class Codes: H02J 1/16 using dynamo-electric machines coupled to flywheels
• CPC Class Codes: H02J 3/30 using dynamo-electric machines coupled to flywheels
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

A motor drive apparatus includes an AC/DC converter which converts AC power supplied from a power supply to DC power, a DC/AC converter which converts DC power to AC power and vice versa, a DC link unit which connects the DC side of the AC/DC converter to the DC side of the DC/AC converter and delivers the DC power from one to the other and vice versa, an energy storage unit which includes at least one capacitor storage unit and at least one flywheel storage unit each of which is connected to the DC link unit and stores or supplies the DC power, and an energy control unit which performs control so that the energy storage unit stores or supplies the DC power.

Claims

1. A motor drive apparatus, comprising:

an AC/DC converter configured to convert AC power supplied from an AC power supply to DC power;

a DC/AC converter configured to convert DC power to AC power for driving a motor or convert AC power regenerated by the motor back to DC power;

a DC link unit which connects a DC side of the AC/DC converter to a DC side of the DC/AC converter to deliver the DC power between the DC side of the AC/DC converter and the DC side of the DC/AC converter;

an energy storage unit which includes at least one capacitor storage unit and at least one flywheel storage unit each of which is connected to the DC link unit and configured to store the DC power supplied from the DC link unit and supply the stored DC power to the DC link unit;

a motor control unit configured to, based on a motor operation command for commanding operation of the motor, perform control so that the DC/AC converter outputs desired AC power; and

an energy control unit configured to perform control so that the energy storage unit stores the DC power supplied from the DC link unit or supplies the stored DC power to the DC link unit,

wherein the energy control unit is configured to

during acceleration control of the motor performed by the motor control unit, cause both the capacitor storage unit and the flywheel storage unit to supply the DC power to the DC link unit at a constant power supply ratio between amounts of the DC power that the capacitor storage unit and the flywheel storage unit supply to the DC link unit, and

during deceleration control of the motor performed by the motor control unit, cause both the capacitor storage unit and the flywheel storage unit to store the DC power from the DC link unit at a constant a power storage ratio between amounts of the DC power that the capacitor storage unit and the flywheel storage unit store from the DC link unit.

2. The motor drive apparatus according to claim 1, wherein, when the AC power that is supplied from the AC power supply to the motor via the AC/DC converter, the DC link unit, and the DC/AC converter exceeds a predetermined limiting value, the energy control unit is configured to perform control so that the energy storage unit outputs the DC power necessary to provide an amount of AC power equal to the AC power required to drive the motor minus the predetermined limiting value.

3. The motor drive apparatus according to claim 1, wherein, when the AC power regenerated by the motor and returned to the AC power supply via the DC/AC converter, the DC link unit, and the AC/DC converter exceeds a predetermined limiting value, the energy control unit is configured to perform control so that the energy storage unit stores the DC power obtained by converting an amount of AC power equal to the AC power regenerated by the motor minus the predetermined limiting value.

4. The motor drive apparatus according to claim 1, wherein the energy control unit is configured to perform control so that the energy storage unit stores the DC power from the DC link unit when the motor is stopped or when the AC power necessary for driving the motor is not greater than a predetermined value.

5. The motor drive apparatus according to claim 1, wherein

when the motor control unit controls the motor to accelerate at a first acceleration rate, the energy control unit is configured to cause the capacitor storage unit and the flywheel storage unit to supply the DC power to the DC link unit at a first power supply ratio between an amount of the DC power that the capacitor storage unit supplies to the DC link unit and an amount of the DC power that the flywheel storage unit supplies to the DC link unit, and

when the motor control unit controls the motor to accelerate at a second acceleration rate greater than the first acceleration rate, the energy control unit is configured to cause the capacitor storage unit and the flywheel storage unit to supply the DC power to the DC link unit at a second power supply ratio between the amount of the DC power that the capacitor storage unit supplies to the DC link unit and the amount of the DC power that the flywheel storage unit supplies to the DC link unit, and

the second power supply ratio is greater than the first power supply ratio.

6. A motor drive apparatus, comprising:

an AC/DC converter configured to convert AC power supplied from an AC power supply to DC power;

a DC/AC converter configured to convert DC power to AC power for driving a motor or convert AC power regenerated by the motor back to DC power;

a DC link unit which connects a DC side of the AC/DC converter to a DC side of the DC/AC converter to deliver the DC power between the DC side of the AC/DC converter and the DC side of the DC/AC converter;

an energy storage unit which includes at least one capacitor storage unit and at least one flywheel storage unit each of which is connected to the DC link unit and configured to store the DC power supplied from the DC link unit and supply the stored DC power to the DC link unit;

a motor control unit configured to, based on a motor operation command for commanding operation of the motor, perform control so that the DC/AC converter outputs desired AC power; and

an energy control unit configured to perform control so that the energy storage unit stores the DC power supplied from the DC link unit or supplies the stored DC power to the DC link unit,

wherein the energy control unit performs control so that

the DC power that the energy storage unit supplies to the DC link unit is supplied only from the capacitor storage unit when the supply of the DC power from the energy storage unit is started, and

when the amount of DC power stored in the capacitor storage unit has decreased to or below a predetermined amount of power, the DC power is supplied only from the flywheel storage unit.

7. The motor drive apparatus according to claim 6, wherein the energy control unit performs control so that

the DC power that the energy storage unit stores from the DC link unit is stored only in the capacitor storage unit when the storage of the DC power by the energy storage unit is started, and

when the amount of DC power stored in the capacitor storage unit has reached or exceeded a predetermined amount of power, the DC power is stored only in the flywheel storage unit.

8. The motor drive apparatus according to claim 6, wherein

a charging or discharging speed of the capacitor storage unit is greater than that of the flywheel storage unit, and

a storable amount of energy of the capacitor storage unit is smaller than that of the flywheel storage unit.

9. A motor drive apparatus, comprising:

an AC/DC converter configured to convert AC power supplied from an AC power supply to DC power;

a DC/AC converter configured to convert DC power to AC power for driving a motor or convert AC power regenerated by the motor back to DC power;

a DC link unit which connects a DC side of the AC/DC converter to a DC side of the DC/AC converter to deliver the DC power between the DC side of the AC/DC converter and the DC side of the DC/AC converter;

an energy storage unit which includes at least one capacitor storage unit and at least one flywheel storage unit each of which is connected to the DC link unit and configured to store the DC power supplied from the DC link unit and supply the stored DC power to the DC link unit;

a motor control unit configured to, based on a motor operation command for commanding operation of the motor, perform control so that the DC/AC converter outputs desired AC power; and

an energy control unit configured to perform control so that the energy storage unit stores the DC power supplied from the DC link unit or supplies the stored DC power to the DC link unit,

wherein the energy control unit is configured to perform control so that, when the rate of increase of the DC power that the energy storage unit supplies to the DC link unit is not greater than a predetermined value, the DC power is supplied only from the flywheel storage unit.

10. The motor drive apparatus according to claim 9, wherein the energy control unit is configured to perform control so that, when the rate of increase of the DC power that the energy storage unit supplies to the DC link unit is greater than the predetermined value, the DC power is supplied only from the capacitor storage unit.

11. The motor drive apparatus according to claim 9, wherein the energy control unit is configured to perform control so that, when the rate of increase of the DC power that the energy storage unit stores from the DC link unit is not greater than a predetermined value, the DC power is stored only in the flywheel storage unit.

12. The motor drive apparatus according to claim 11, wherein the energy control unit is configured to perform control so that, when the rate of increase of the DC power that the energy storage unit stores from the DC link unit is greater than the predetermined value, the DC power is stored only in the capacitor storage unit.

13. The motor drive apparatus according to claim 11, wherein the energy control unit is configured to perform control so that, when the rate of increase of the DC power that the energy storage unit stores from the DC link unit is greater than the predetermined value, the DC power is stored in both the capacitor storage unit and the flywheel storage unit.

14. The motor drive apparatus according to claim 9, wherein the energy control unit is configured to perform control so that, when the rate of increase of the DC power that the energy storage unit supplies to the DC link unit is greater than the predetermined value, the DC power is supplied from both the capacitor storage unit and the flywheel storage unit.

15. A motor drive apparatus, comprising:

an AC/DC converter which converts AC power supplied from an AC power supply to DC power;

a DC/AC converter which converts DC power to AC power for driving a motor or converts AC power regenerated by the motor back to DC power;

a DC link unit which connects a DC side of the AC/DC converter to a DC side of the DC/AC converter and delivers the DC power from one to the other and vice versa;

an energy storage unit which includes at least one capacitor storage unit and at least one flywheel storage unit each of which is connected to the DC link unit and stores the DC power supplied from the DC link unit or supplies the stored DC power to the DC link unit;

a motor control unit which, based on a motor operation command for commanding operation of the motor, performs control so that the DC/AC converter outputs desired AC power; and

an energy control unit which performs control so that the energy storage unit stores the DC power supplied from the DC link unit or supplies the stored DC power to the DC link unit,

wherein the energy control unit performs control so that

the DC power that the energy storage unit supplies to the DC link unit is supplied only from the capacitor storage unit when an amount of DC power supplied from the energy storage unit to the DC link unit is not larger than a predetermined amount of power, and

when the amount of DC power supplied from the energy storage unit to the DC link unit is larger than the predetermined amount of power, the DC power is supplied only from the flywheel storage unit or from both the capacitor storage unit and the flywheel storage unit.

16. The motor drive apparatus according to claim 15, wherein the energy control unit performs control so that

the DC power that the energy storage unit stores from the DC link unit is stored only in the capacitor storage unit when an amount of DC power stored in the energy storage unit from the DC link unit is not larger than a predetermined amount of power, and

when the amount of DC power stored in the energy storage unit from the DC link unit is larger than the predetermined amount of power, the DC power is stored only in the flywheel storage unit or in both the capacitor storage unit and the flywheel storage unit.

17. The motor drive apparatus according to claim 16, wherein the energy control unit performs control so that, when the amount of DC power stored in the energy storage unit from the DC link unit is larger than the predetermined amount of power, the DC power is stored only in the flywheel storage unit.

18. The motor drive apparatus according to claim 15, wherein the energy control unit performs control so that, when the amount of DC power supplied from the energy storage unit to the DC link unit is larger than the predetermined amount of power, the DC power is supplied only from the flywheel storage unit.