Power converter controlling apparatus and method providing ride through capability during power interruption in a motor drive system

• US 20060061320A1
• Filed: 11/02/2004
• Published: 03/23/2006
• Est. Priority Date: 09/21/2004
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Wang, Zheng, Zhou, George You, Ma, Jack Daming
• Granted Patent: US 7,116,067 B2
• Time in Patent Office: Days
• US Class Current: 318/801
• CPC Class Codes: H02P 23/0004 Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
• CPC Class Codes: H02P 29/025 the fault being a power interruption
• CPC Class Codes: H02P 6/08 Arrangements for controlling the speed or torque of a single motor H02P6/10, H02P6/28 take precedence
• CPC Class Codes: H02P 6/24 Arrangements for stopping

Abstract

A method of controlling a power converter (20) of a motor drive system (10)controls the power converter (20) during a first operating mode by applying a current control scheme, which sets power converter commands to control torque current flowing from the power converter (20) to the motor (30) to achieve desired motor speed; and initiates a second operating mode when power supply to the power converter (20) is interrupted. The second operating mode includes controlling negative torque current between the power converter (20) and the motor (30) so that mechanical energy from the motor (30) charges an element (58) on a power supply side of the power converter (20). The first operating mode is resumed when the input power recovers. Torque current between the power converter (20) and the motor (30) is also controlled to limit a maximum transient DC bus voltage.

Claims

1. A method of controlling a power converter of a motor drive system, said method comprising:

controlling said power converter during a first operating mode by applying a current control scheme, which sets power converter commands to control torque current flowing from said power converter to the motor to achieve desired motor speed;

initiating a second operating mode when power supply to said power converter is interrupted, wherein said second operating mode includes controlling a negative torque current between said power converter and said motor so that mechanical energy from said motor charges an element on a power supply side of said power converter;

controlling the torque current between said power converter and said motor to limit maximum transient DC bus voltage;

monitoring DC bus voltage between said power converter and said power supply; and

comparing the monitored DC bus voltage to a reference value;

wherein torque current between said power converter and said motor is controlled based on the result of said comparing step to limit a maximum DC bus voltage during transition between the first and second operating modes.

2. The method according to claim 1, wherein said element on the power supply side of said power converter is a DC link capacitor.

3. The method according to claim 1, wherein, during said second operating mode, said motor functions as a generator and said power converter functions as an active rectifier to charge said element.

4. The method according to claim 1, wherein said motor decelerates during second operating mode, and said method further comprises:

switching to said first operating mode after power input to said power converter is recovered.

5. The method according to claim 4, wherein said step of switching to said first operating mode after power input to said power converter is recovered is performed without a soft start sequence.

6. The method according to claim 4, wherein

said current control scheme in said first operating mode is applied based on motor speed/position information, and

said speed/position information is monitored during said second operating mode, such that a re-synchronization process is not needed upon switching to said first operating mode.

7. The method according to claim 1, wherein said power converter is an inverter.

8. The method according to claim 1, wherein said power converter is connected to a DC power supply via a DC link, wherein DC link voltage in said second operating mode is higher than DC link voltage in said first operating mode.

10. The method according to claim 1, wherein

said current control scheme in said first operating mode is applied based on motor speed/position information, and

said motor drive system is a speed sensorless system.

11. The method according to claim 1, wherein

said current control scheme in said first operating mode is applied based on motor speed/position information, and

said motor drive system includes a motor speed sensor.

12. The method according to claim 1, wherein

said second operating mode provides ride through capability during power interruption.

13. The method according to claim 1, wherein said motor drive system is an aerospace motor drive system.

14. The method according to claim 1, wherein transition between said first and second operating modes is a hard switch.

9. (canceled)

15. A power converter controlling apparatus for controlling a power converter of a motor drive system, said controlling apparatus comprising:

a current controller, which outputs gating signals to said power converter as a function of a torque current reference and a flux current reference; and

a torque current reference generator, which generates the torque current reference used by said current controller, wherein

said current controller controls said power converter during a first operating mode to create torque current flowing from said power converter to the motor to achieve desired motor speed;

controls the power converter in a second operating mode, initiated when power to said power converter is interrupted, so that negative torque current between said power converter and said motor draws mechanical energy from said motor and charges an element on a power supply side of said power converter; and

controls the torque current between said power converter and said motor to limit maximum transient bus voltage;

wherein said torque current reference generator;

monitors DC bus voltage between said power converter and the power supply;

compares the monitored DC bus voltage to a reference value; and

controls a torque current reference based on the result of said comparing step to limit a maximum DC bus voltage during transition between the first and second operating modes.

16. The apparatus according to claim 15, wherein said element on the power supply side of said power converter is a DC link capacitor.

17. The apparatus according to claim 15, wherein, during said second operating mode, said motor functions as a generator and said power converter functions as an active rectifier to charge said element.

18. The apparatus according to claim 15, wherein said motor decelerates during second operating mode, and said torque current reference generator:

switches to said first operating mode after power input to said power converter is recovered.

19. The apparatus according to claim 18, wherein said torque current reference generator switches to said first operating mode after power input to said power converter is recovered without requiring a soft start sequence.

20. The apparatus according to claim 15, wherein

said first operating mode is applied based on motor speed/position information, and

said torque current reference generator monitors speed/position information during said second operating mode, such that a re-synchronization process is not needed upon switching to said first operating mode.

21. The apparatus according to claim 15, wherein said power converter is an inverter.

22. The apparatus according to claim 15, wherein said power converter is connected to a DC power supply via a DC link, wherein DC link voltage in said second operating mode is higher than DC link voltage in said first operating mode.

24. The apparatus according to claim 15, wherein

said current control scheme in said first operating mode is applied based on motor speed/position information, and

said motor drive system is a speed sensorless system.

25. The apparatus according to claim 15, wherein

said current control scheme in said first operating mode is applied based on motor speed/position information, and

said motor drive system includes a motor speed sensor.

26. The apparatus according to claim 15, wherein

said second operating mode provides ride through capability during power interruption.

27. The apparatus according to claim 15, wherein said motor drive system is an aerospace motor drive system.

28. The apparatus according to claim 15, wherein transition between said first and second operating modes is a hard switch.

23. (canceled)