Method for boosting the output voltage of a variable...

Electricity: motive power systems – Automatic and/or with time-delay means – Terminal voltage or counter-electromotive force of...

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C318S500000, C363S074000

Reexamination Certificate

active

06586900

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to power systems for subterranean bore hole equipment and, more specifically, to boosting the output of variable frequency drives employed to power electrical submersible pumps within well bores.
BACKGROUND OF THE INVENTION
Electrical power is frequently transmitted to subterranean locations within boreholes to power downhole equipment, such as electrical submersible pumps (ESPs). Normally three phase electrical power is transmitted from the surface over cables running between the well casing and the production tubing.
In some downhole applications, high voltage electrical power is required. For example, electrical motors for ESPs may require voltages of 1,000 to 5,000 volts at the surface. However, electrical drives capable of providing output voltages at the required level may not be available, or may not be economical even when available. When lower output voltage drives are employed in such situations, typically step-up transformers at the output of the drive are utilized to boost the voltage of power transmitted downhole. Step-up transformers add to the expense of the system, however, and add additional sources of failure or disturbance to the electrical system.
There is, therefore, a need in the art for a system allowing an electric drive having a maximum output voltage lower than required to be utilized to power downhole equipment while eliminating the need for step-up transformers. It would further be advantageous to smooth the output of a pulse width modulated variable frequency drive while boosting the output voltage.
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide, for use in powering downhole equipment, a sine wave filter including an inductor for each phase (three inductors) and three delta- or Y-connected capacitors. The sine wave filter is coupled within a three phase power system at the surface, between the output of a variable frequency drive and a three phase power cable transmitting power to a borehole location to boost the output voltage of the drive. The sine wave filter is designed to have a resonant frequency higher than the maximum operational frequency of the drive, and a Q such that, at the maximum operational frequency of the drive, the filter provides a voltage gain equal to the ratio of the desired voltage to the drive's maximum output power at the maximum operational frequency. The sine wave filter also smooths the voltage waveform of a pulse width modulated variable frequency drive.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art will appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art will also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words or phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, whether such a device is implemented in hardware, firmware, software or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.


REFERENCES:
patent: 4138715 (1979-02-01), Miller
patent: 4196469 (1980-04-01), Gurwicz
patent: 4413313 (1983-11-01), Robinson
patent: 4541041 (1985-09-01), Park et al.
patent: 4574342 (1986-03-01), Runyan
patent: 4833584 (1989-05-01), Divan
patent: 4862342 (1989-08-01), Dhyanchand et al.
patent: 4928771 (1990-05-01), Vandevier
patent: 5208738 (1993-05-01), Jain
patent: 5844397 (1998-12-01), Konecny et al.
patent: 5909098 (1999-06-01), Konecny et al.
patent: 5930131 (1999-07-01), Feng
patent: 6135732 (2000-10-01), Angorin
patent: 0 413 514 (1991-02-01), None
“A Zero-Current-Siwtching Based Three-Phase PWM Inverter Having Resonant Circuits on AC-Side,” H. Akagi and M. Kohata, Okayama University, Toyo Electric Mfg. Co. Ltd., 1993 IEEE Industry App conference, Twenty-Eighth IAS Annual Meeting, pp. 821-826.
“Design and Implementation of an Inverter Output LC Filter Used for DV/DT Reduction,” by Thomas Rajendra Naik and Thomas A. Nondahl, 1999 Fourteenth Annual Applied Power Electronics Conference Exposition, IEEE, vol. 2, Mar. 14, 1999, pp. 1279-1284.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Method for boosting the output voltage of a variable... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method for boosting the output voltage of a variable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for boosting the output voltage of a variable... will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-3032061

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.