Power distribution systems

Patent metadata

Field	Value
Publication number	US-10530152-B2
Application number	US-201615741771-A
Country	US
Kind code	B2
Filing date	Jul 8, 2016
Priority date	Jul 16, 2015
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A power distribution system has a power converter with a plurality of semiconductor switching devices per phase, a PWM controller, and a current limitation controller. The current limitation controller is adapted, at least when a short-circuit fault is detected, to calculate the difference between a measured current for each phase and a reference current for the corresponding phase. If the calculated difference is located outside a predetermined current range centered about the reference current for the corresponding phase, the current limitation controller will allow the semiconductor switching devices of the corresponding phase to be turned on and off by the PWM controller. Otherwise, if the calculated difference is located inside the predetermined current range, the current limitation controller will control the semiconductor switching devices for the corresponding phase to be turned off irrespective of the PWM control strategy applied by the PWM controller.

First claim

The invention claimed is:

1. A power distribution system having one or more phases, the power distribution system comprising a power converter with a plurality of semiconductor switching devices per phase, a pulse width modulation controller, and a current limitation controller adapted, at least when a short-circuit fault is detected, to:
calculate the difference between a measured current for each phase and a reference current for the corresponding phase; and
if the calculated difference is located outside a predetermined current range centered about the reference current for the corresponding phase, allow the semiconductor switching devices of the corresponding phase to be turned on and off by the PWM controller;
if the calculated difference is located inside the predetermined current range, control the semiconductor switching devices for the corresponding phase to be turned off.

2. The power distribution system according to claim 1 , wherein the PWM controller generates a first signal per phase having a first value indicating that the semiconductor switching devices for the corresponding phase should be turned on and a second value indicating that the semiconductor switching device for the corresponding phase should be turned off; and
wherein the current limitation controller is further adapted, at least when a short-circuit fault is detected, to:
generate a second signal per phase having a first value indicating that the semiconductor switching devices for the corresponding phase can be turned on if the calculated difference is located outside a predetermined current range centered about the reference current for the corresponding phase or a second value indicating that the semiconductor switching devices for the corresponding phase should be turned off if the calculated difference is located inside a predetermined current range; and
use the first and second signals to generate a third signal per phase having a first value indicating that the semiconductor switching devices for the corresponding phase should be turned on and a second value indicating that the semiconductor switching devices for the corresponding phase should be turned off, the current limitation controller optionally being adapted to generate each third signal by applying a logical conjunction to the corresponding first and second signals.

3. The power distribution system according to claim 2 , wherein each third signal has the first value if both the corresponding first and second signals have the first value and otherwise the third signal has the second value.

4. The power distribution system according to claim 1 , wherein the current limitation controller includes an on-off controller for each phase with a proportional band that is centered about the reference current for the corresponding phase and which defines the predetermined current range.

5. The power distribution system according to claim 4 , wherein each on-off controller receives the calculated difference between the measured current and the reference current for the corresponding phase as an input, and provides the second signal as an output.

6. The power distribution system according to claim 1 , further comprising an electrical machine.

7. The power distribution system according to claim 6 , wherein the electrical machine forms part of a hybrid drive system further comprising a prime mover, the rotor of the electrical machine and the driving end of the prime mover being mechanically coupled to a load by means of a mechanical linkage such as a clutch and/or gearbox.

8. The power distribution system according to claim 6 , further comprising an ac bus and wherein the electrical machine is electrically connected to the ac bus by the power converter.

9. The power distribution system according to claim 8 , wherein the power converter has ac input terminals electrically connected to the ac bus of the power distribution system, and dc output terminals.

10. The power distribution system according to claim 9 , further comprising a second power converter having dc input terminals electrically connected to the dc output of the power converter by a dc link, and ac output terminals electrically connected to the electrical machine.

11. The power distribution system according to claim 1 , wherein the reference current and/or the current range for each phase is/are determined with reference to design parameters of the power converter and/or the power distribution system.

12. A short-circuit fault ride-through method for a power distribution system having one or more phases, the power distribution system comprising a power converter with a plurality of semiconductor switching devices per phase, the method comprising the steps of:
calculating the difference between a measured current for each phase and a reference current for the corresponding phase; and
if the calculated difference is located outside a predetermined current range centered about the reference current for the corresponding phase, allowing the semiconductor switching devices of the corresponding phase to be turned on and off;
if the calculated difference is located inside the predetermined current range, controlling the semiconductor switching devices for the corresponding phase to be turned off.

13. A method according to claim 12 , further comprising the steps of:
generating a first signal per phase having a first value indicating that the semiconductor switching devices for the corresponding phase should be turned on and a second value indicating that the semiconductor switching device for the corresponding phase should be turned off;
generating a second signal per phase having a first value indicating that the semiconductor switching devices for the corresponding phase can be turned on if the calculated difference is located outside the predetermined current range centered about the reference current for the corresponding phase or a second value indicating that the semiconductor switching devices for the corresponding phase should be turned off if the calculated difference is located inside a predetermined current range; and
using the first and second signals to generate a third signal per phase having a first value indicating that the semiconductor switching devices for the corresponding phase should be turned on and a second value indicating that the semiconductor switching devices for the corresponding phase should be turned off, each third signal optionally being generated by applying a logical conjunction to the corresponding first and second signals.

14. The method according to claim 12 , wherein the power distribution system further comprises an ac bus electrically connected to the power converter, and the power converter provides controlled overcurrent to the ac bus until the short-circuit fault is cleared.

15. The method according to claim 12 , wherein the reference current and/or the current range for each phase is/are determined with reference to design parameters of the power converter and/or the power distribution system.

Assignees

• Ge Energy Power Conversion Technology Ltd

Inventors

• Long Teng
• Mupambireyi Ushindibaba

Classifications

• Y10S903/93

  Conjoint control of different elements · CPC title

• H02H7/1227

  responsive to abnormalities in the output circuit, e.g. short circuit · CPC title

• B60L2200/32

  Waterborne vessels · CPC title

• H02M5/458

  using semiconductor devices only · CPC title

• H02H9/08 Primary

  Limitation or suppression of earth fault currents, e.g. Petersen coil · CPC title