Reducing peak fault output current in a DC power generation system

Patent metadata

Field	Value
Publication number	US-9608551-B2
Application number	US-201514828079-A
Country	US
Kind code	B2
Filing date	Aug 17, 2015
Priority date	Aug 17, 2015
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

Technologies for reducing peak fault output current in a DC power generation system include a generator having a reduced damper winding and a controller to control a rectifier array to generate a DC power output. In some embodiments, the generator may have no damper windings, may have damper windings including a reduced number of damper bars, and/or may have damper windings having separated end ring mounts for each damper bar. The controller is configured to control the rectifier array so as to reduce oscillations of the DC output that may be due to the reduced damper windings. To do so, the controller is configured to generate the control signal based on an oscillation component of the DC power output. For example, the controller may generate an oscillation correction signal based on the DC power output and adjust a firing angle set point of the rectifier array based on the oscillation correction signal.

First claim

The invention claimed is:

1. A direct current (DC) power generation system for reducing peak fault output current, the DC power generation system comprising:
a generator configured to generate an alternating current (AC) power output in response to an excitation, wherein the generator includes a plurality of rotor poles and each rotor pole includes a corresponding damper winding, wherein each damper winding includes a plurality of damper bars secured to the corresponding rotor pole by a pair of end rings, wherein each end ring comprises at least two end ring mounts electrically isolated from each other and wherein each end ring mount secures at least one damper winding to the corresponding rotor pole;
a rectifier array configured to convert the AC power output to a DC power output in response to a control signal; and
a controller electrically coupled to rectifier array to control operation of the rectifier array, wherein the controller is configured to generate the control signal based on an oscillation component of the DC power output.

2. The DC power generation system of claim 1 , wherein each end ring comprises a plurality of end ring mounts and each end ring mount secures one of the plurality of damper bars to the corresponding rotor pole, wherein each end ring mount is electrically isolated from each other end ring mount.

3. The DC power generation system of claim 1 , wherein the at least two end ring mounts includes a first end ring mount and a second end ring mount and each of the first and second end ring mounts secure a different number of damper bars to the corresponding rotor pole.

4. The DC power generation system of claim 1 , wherein the end ring mounts of the end ring define a damper winding configuration of the corresponding damper winding, and wherein at least two rotor poles of the plurality of rotor poles include damper windings having different damper winding configurations.

5. The DC power generation system of claim 1 , wherein the controller is configured to generate an oscillation correction signal and adjust a firing angle set point based on the oscillation correction signal to generate the control signal.

6. The DC power generation system of claim 5 , wherein the controller is configured to receive a measurement signal indicative of a DC current of the DC power output, apply a phase compensation to the measurement signal to generate a compensated measurement signal, and apply a gain to the compensated measurement signal to generate the oscillation correction signal.

7. The DC power generation system of claim 6 , wherein the controller comprises:
a noise filter configured to receive the measurement signal and filter the measurement signal to generate a filtered measurement signal;
a phase compensation circuit coupled to the noise filter to receive the filtered measurement signal and configured to apply the phase compensation to the filtered measurement signal to generate the compensated measurement signal; and
a gain circuit coupled to the phase compensation circuit to receive the compensated measurement signal and configured to apply the gain to the compensated measurement signal to generate the oscillation correction signal.

8. The DC power generation system of claim 5 , wherein the controller is configured to receive a measurement signal indicative of a DC current of the DC power output, separate the measurement signal into a DC component signal and an oscillation component signal, apply a phase compensation to the oscillation component signal to generate a compensated oscillation component signal, apply an oscillation damping gain to the compensated oscillation component signal to generate an adjusted oscillation component signal, apply a voltage droop gain to the DC component signal to generate an adjusted DC component signal, and sum the adjusted oscillation component signal and the adjusted DC component signal to generate the oscillation correction signal.

9. The DC power generation system of claim 8 , wherein the controller comprises:
a noise filter configured to receive the measurement signal and filter the measurement signal to generate a filtered measurement signal;
a low pass filter coupled to the noise filter to receive the filtered measurement signal and filter the filtered measurement signal to generate the DC component signal;
a first summation circuit coupled to the noise filter to receive the filtered measurement signal and to the low pass filter to receive the DC component signal, wherein the first summation circuit is configured to subtract the DC component signal from the filtered measurement signal to generate the oscillation component signal;
a phase compensation circuit coupled to the first summation circuit to receive the oscillation component signal and configured to apply the phase compensation to the oscillation component signal to generate the compensated oscillation component signal;
an oscillation damping gain circuit coupled to the phase compensation circuit to receive the compensated oscillation component signal and configured to apply the oscillation damping gain to the compensated oscillation component signal to generate the adjusted oscillation component signal;
a voltage droop gain circuit coupled to the low pass filter to receive the DC component signal and configured to apply the voltage droop gain to the DC component signal to generate the adjusted DC component signal; and
a second summation circuit coupled to the oscillation damping gain circuit to receive the adjusted oscillation component signal and to the voltage droop gain circuit to receive the adjusted DC component signal, wherein the second summation circuit is configured to sum the adjusted oscillation component signal and the adjusted DC component signal to generate the oscillation correction signal.

10. The DC power generation system of claim 5 , wherein the controller is configured to determine the cosine of the firing angle set point to generate a command value, subtract the oscillation correction signal from the command value to generate a corrected command value, determine an inverse cosine of the target value to generate a command firing angle, and apply a phase limiter to the command firing angle to limit the command firing angle within a reference angle range to generate the control signal.

11. A direct current (DC) power generation system for generating a DC power output having reduced peak fault output current, the DC power generation system comprising:
a controller coupled to a rectifier array of the DC power generation system and to generate a control signal to control operation of the rectifier array to generate the DC power output, wherein the controller is configured to generate an oscillation correction signal and adjust a firing angle set point based on the oscillation correction signal to generate the control signal.

12. The DC power generation system of claim 11 , wherein the controller is configured to receive a measurement signal indicative of a DC current of the DC power output, apply a phase compensation to the measurement signal to generate a compensated measurement signal, and apply a gain to the compensated measurement signal to generate the oscillation correction signal.

13. The DC power generation system of claim 11 , wherein the controller is configured to receive a measurement signal indicative of a DC current of the DC power output, separate the measurement signal into a DC component signal and an oscillation component signal, apply a phase compensation to the oscillation component signal to generate a compensated oscillation component signal, apply an oscillation damping gain to the compensated oscillati

Assignees

• Abb Schweiz Ag

Inventors

• Ouyang Wen
• Liang Jiaqi
• Qi Li

Classifications

• H02P9/006 Primary

  Means for protecting the generator by using control (control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10) · CPC title

• H02M7/00

  Conversion of AC power input into DC power output; Conversion of DC power input into AC power output · CPC title

• H02K19/10

  for multi-phase current · CPC title

• H02M7/1557

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

• H02M1/081

  wherein the phase of the control voltage is adjustable with reference to the AC source · CPC title