High dynamic control apparatus for current source converter

Patent metadata

Field	Value
Publication number	US-9240733-B2
Application number	US-201314042756-A
Country	US
Kind code	B2
Filing date	Oct 1, 2013
Priority date	Oct 1, 2013
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

Current source converters and control methods are presented for high dynamic performance by implementing a DC link current control loop parallel to one or more motor control loops, with a DC link current control command value for operating the current source rectifier being derived at least partially independent of the motor control command values, wherein certain implementations drive the current source rectifier to its maximum rated value, or the DC current command value can be set above an amount required by the current source inverter using a gain factor which can be fixed or can itself be adjusted based on one or more motor control error values for balancing as-needed dynamic performance and efficiency.

First claim

The following is claimed:

1. A motor drive, comprising:
a current source rectifier including a plurality of rectifier switching devices individually operable according to a corresponding one of a plurality of rectifier switching control signals to provide controlled DC current;
an intermediate DC circuit comprising at least one inductance and first and second DC current paths coupled with corresponding first and second DC output nodes of the current source rectifier;
a current source inverter including a plurality of inverter switching devices individually operable according to a corresponding one of a plurality of inverter switching control signals to selectively couple a corresponding one of the first and second DC current paths of the intermediate DC circuit with, a corresponding AC output node to provide controlled AC output current for driving a motor load; and
a controller programmed to implement at least one motor control loop to control at least one operating parameter of the motor load by providing the inverter switching control signals to cause the current source inverter to selectively convert DC current from the intermediate DC circuit to regulate the AC output current provided to the motor load in a closed-loop fashion according to at least one motor command signal or value, the controller being programmed to implement a DC current control loop outside the at least one motor control loop by providing the rectifier switching control signals to cause the current source rectifier to selectively convert AC input power to regulate the DC current provided to the intermediate DC circuit by the current source rectifier in a closed-loop fashion according to at least one DC current command signal or value derived at least partially independent of the at least one motor command signal or value;
wherein the controller is programmed to implement the DC current control loop by providing the rectifier switching control signals upon powerup of the motor drive according to the DC current command signal or value, with the DC current command signal or value set to a maximum rated DC current of the current source rectifier for a predetermined time upon and after power up of the motor drive, and thereafter with the DC current command signal or value computed as a product of a magnitude of at least one inverter current command signal or value from the at least one motor control loop and a gain value, wherein the gain value is greater than 1.0.

2. The motor drive of claim 1 , wherein the gain value is from 1.1 to 1.5.

3. The motor drive of claim 2 , wherein the controller is programmed to allow a user to adjust the gain value.

4. The motor drive of claim 2 , wherein the controller is programmed to automatically adjust the gain value according to at least one error signal or value computed for the at least one motor control loop, with the controller selectively increasing the gain value for increases in the at least one error signal or value, and vice versa.

5. The motor drive of claim 1 , wherein the controller is programmed to allow a user to adjust the gain value.

6. The motor drive of claim 1 , wherein the controller is programmed to automatically adjust the gain value within a predefined range according to at least one error signal or value computed for the at least one motor control loop, with the controller selectively increasing the gain value within the predefined range for increases in the at least one error signal or value and vice versa.

7. The motor drive of claim 6 , wherein the controller is programmed to automatically adjust the gain value within the predefined range at least partially according to a speed error signal or value computed for the at least one motor control loop.

8. The motor drive of claim 7 , wherein the controller is programmed to automatically adjust the gain value within the predefined range at least partially according to a torque error signal or value computed for the at least one motor control loop.

9. The motor drive of claim 6 , wherein the controller is programmed to automatically adjust the gain value within the predefined range at least partially according to a torque error signal or value computed for the at least one motor control loop.

10. The motor drive of claim 6 , wherein the controller is programmed to automatically adjust the gain value within the predefined range at least partially according to a flux error signal or value computed for the at least one motor control loop.

11. A motor drive, comprising:
a current source rectifier including a plurality of rectifier switching devices individually operable according to a corresponding one of a plurality of rectifier switching control signals to provide controlled DC current;
an intermediate DC circuit comprising at least one inductance and first and second DC current paths coupled with corresponding first and second DC output nodes of the current source rectifier;
a current source inverter including a plurality of inverter switching devices individually operable according to a corresponding one of a plurality of inverter switching control signals to selectively couple a corresponding one of the first and second DC current paths of the intermediate DC circuit with a corresponding AC output node to provide controlled AC output current for driving a motor load; and
a controller programmed to implement at least one motor control loop to control at least one operating parameter of the motor load by providing the inverter switching control signals to cause the current source inverter to selectively convert DC current from the intermediate DC circuit to regulate the AC output current provided to the motor load in a closed-loop fashion according to at least one motor command signal or value, the controller being programmed to implement a DC current control loop outside the at least one motor control loop by providing the rectifier switching control signals to cause the current source rectifier to selectively convert AC input power to regulate the DC current provided to the intermediate DC circuit by the current source rectifier in a closed-loop fashion according to at least one DC current command signal or value derived at least partially independent of the at least one motor command signal or value;
wherein the controller is programmed to implement the DC current control loop independent from the at least one motor control loop by providing the rectifier switching control signals to cause the current source rectifier to selectively convert AC input power to regulate the DC current provided to the intermediate DC circuit by the current source rectifier in a closed-loop fashion according to a constant DC current command signal or value; and
wherein the controller is programmed to provide pulse width modulated inverter switching control signals according to at least one inverter current command signal or value from the at least one motor control loop using a modulation index computed according to a magnitude of the at least one inverter current command signal or value scaled by a value of the DC current.

12. A method for controlling a current source converter having a current source rectifier, a current source inverter driving an AC load, and an intermediate DC circuit, the method comprising:
using at least one processor, implementing at least one load control loop to control at least one operating parameter of a load by providing inverter switching control signals to cause the current source inverter to selectively convert DC current from the intermediate DC circuit to regulate AC output current provided to the AC load in a closed-loop fashion according to at least one load command signal or value;
using

Assignees

• Royak Semyon
• Pande Manish
• Dai Jingya
• Nam Sang Woo
• Al-Nabi Ehshan
• Rockwell Automation Tech Inc

Inventors

• Royak Semyon
• Pande Manish
• Dai Jingya
• Nam Sang Woo
• Al-Nabi Ehshan

Classifications

• H02M7/1626 Primary

  with automatic control of the output voltage or current · CPC title

• H02M5/4585 Primary

  having a rectifier with controlled elements · CPC title

• H02P21/06

  Rotor flux based control involving the use of rotor position or rotor speed sensors · CPC title

• H02P21/0035

  Electricity · mapped topic

• H02P21/22

  Current control, e.g. using a current control loop · CPC title