Synchronous electric power distribution startup system

Patent metadata

Field	Value
Publication number	US-9979339-B2
Application number	US-201615367023-A
Country	US
Kind code	B2
Filing date	Dec 1, 2016
Priority date	Dec 14, 2015
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

A system includes one or more synchronous generators mechanically coupled to an excitation system. The excitation system is configured to output an excitation signal to excite the synchronous generator to produce a voltage and a current at an output of the synchronous generator. During startup of the synchronous generator, the excitation system may also output pulses of the excitation signal to initiate synchronism of one or more non-rotating electric motors electrically coupled to the synchronous generator. In addition, the pulses may be output to urge rotation of the non-rotating electric motors into rotational electrical alignment with the synchronous generator and each other.

First claim

We claim:

1. A system comprising:
a excitation system configured to output a variable excitation signal; and
a synchronous generator configured to generate power for a plurality of rotational synchronous motor loads based on the variable excitation signal;
the excitation system configured to output the variable excitation signal based on a voltage and current being supplied by the generator to the rotational synchronous motor loads;
the excitation system configured, in response to the rotational synchronous motor loads not rotating, to provide pulses of the excitation signal in a first stage and in a second stage;
the excitation system configured to selectively provide repetitive pulses of the variable excitation signal in the first stage at a predetermined frequency to temporarily energize the rotational synchronous motor loads prior to rotation of the generator; and
the excitation system further configured to selectively provide pulses of the variable excitation signal at a variable frequency in the second stage after rotation of the generator commences, the pulses of the variable excitation at the second stage provided to coincide with the generator and the rotational synchronous motor loads being substantially in electrical alignment.

2. The system of claim 1 , wherein the excitation system is configured to provide pulses of the variable excitation signal in the second stage at times when the generator rotor and the motor rotor are substantially aligned to initiate synchronism.

3. The system of claim 1 , wherein the excitation system comprises an exciter and an excitation controller, the exciter directed by the excitation controller to output a magnitude of the variable excitation signal, and the pulse of variable excitation signal being a step change increase in a magnitude of the variable excitation signal of at least 20%.

4. The system of claim 1 , wherein the excitation system is configured to control the output of the variable excitation signal based on synchronous operation of the generator with the rotational motor synchronous loads after completion of at least one of the first stage or the second stage.

5. The system of claim 1 , wherein the excitation system is configured to selectively provide pulses of the variable excitation signal in the first stage to urge alignment between rotors in each of the plurality of rotational synchronous motor loads.

6. The system of claim 1 , wherein the pulses of the variable excitation signal are selectively applied during the first stage and the second stage based on a position of a rotor of the generator and an average position of a plurality of rotors of the rotational synchronous motor loads.

7. The system of claim 1 , wherein the pulses of the variable excitation signal are selectively applied during the first stage and the second stage based on a magnitude of apparent power being output by the generator.

8. The system of claim 1 , wherein the pulses of the variable excitation signal are selectively applied during the first stage and the second stage at a predetermined cycle and a predetermined accelerating angular difference.

9. A system comprising:
a excitation system configured to output a variable excitation signal; and
a synchronous generator configured to generate output power for a plurality of rotational synchronous motor loads in response to receipt of the variable excitation signal;
the excitation system configured to output a pulse of the variable excitation signal to the generator to urge the plurality of rotational synchronous motor loads into rotational electrical alignment with the synchronous generator based on a corresponding pulse of output power generated by the synchronous generator in response to receipt of the pulse of the variable excitation signal,
the excitation system configured to output the pulse of the variable excitation signal to the generator in a first stage in which rotation of the generator and the plurality of rotational synchronous motor loads is absent and the pulse is repetitively output by the excitation system at a predetermined frequency, and
the excitation system configured to output the pulse of the variable excitation signal to the generator in a second stage in which rotation of the generator is present, rotation of the plurality of the rotational synchronous motor loads is absent, and the pulse is output once during an electric cycle, a frequency of the electric cycle based on a rotational speed of the generator in the second stage.

10. The system of claim 9 , wherein the pulse is a step change between a first magnitude of the variable excitation signal and a second magnitude of the variable excitation signal.

11. The system of claim 9 , wherein the pulse of the variable excitation signal is selectively output to temporarily energize and initiate rotation of the rotational synchronous motor loads into electrical alignment.

12. The system of claim 9 , wherein the pulse of the variable excitation signal is selectively output to temporarily energize and initiate transition of the rotational synchronous motor loads from static friction to dynamic friction.

13. The system of claim 9 , where the pulse of the variable excitation signal is selectively output to initiate a flux linkage between the plurality of synchronous motor loads and the generator at a time of the generator and the plurality of synchronous motor loads being substantially synchronously aligned.

14. A system comprising:
an excitation system configured to output a variable excitation signal; and
a synchronous generator configured to generate power for a plurality of rotational synchronous motor loads based on the variable excitation signal;
the excitation system configured to output the variable excitation signal based on a voltage and current being supplied to the rotational synchronous motor loads;
the excitation system further configured, in response to absence of rotation of at least some of the rotational synchronous motor loads, to selectively provide repetitive pulses of the variable excitation signal at a predetermined frequency in a first stage prior to rotation of the generator to temporarily energize the rotational synchronous motor loads, and in a second stage after rotation of the generator commences, the pulses of the variable excitation signal at the second stage provided at a variable frequency at times when a rotor of the generator and a rotor of the rotational synchronous motor loads are substantially aligned.

15. The system of claim 14 , wherein the excitation system is configured to selectively provide pulses of the variable excitation signal during the first stage at a same angular position a predetermined number of times, the excitation system further configured to subsequently provide pulses of the variable excitation signal during the first stage at another same angular position.

16. The system of claim 14 , wherein the variable excitation signal is a field current supplied to the synchronous generator, and the pulses of variable excitation are a step change in a magnitude of the field current of at least 20%.

17. The system of claim 14 , wherein the pulses of the variable excitation signal are selectively provided at the first stage to urge the rotational synchronous motor loads into alignment with each other, and into synchronism with the generator.

Assignees

• Rolls Royce Nam Tech Inc

Inventors

• Blackwelder Mark Jon
• Rancuret Paul M

Classifications

• H02P1/54

  for starting two or more dynamo-electric motors · CPC title

• H02P9/00

  Arrangements for controlling electric generators for the purpose of obtaining a desired output · CPC title

• H02P5/74

  controlling two or more AC dynamo-electric motors (H02P5/46, H02P5/60 take precedence) · CPC title

• H02P9/08 Primary

  Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation · CPC title

• H02P1/56

  simultaneously · CPC title