George R Andexler

US Patent:

51343568, Jul 28, 1992

Filed:

Mar 7, 1991

Appl. No.:

7/665774

Inventors:

Mohamed A. El-Sharkawi - Renton WA
Subrahmanyam S. Venkata - Woodinville WA
Mingliang Chen - Kirkland WA
George Andexler - Everett WA
Tony Huang - Seattle WA

Assignee:

Board of Regents of the University of Washington - Seattle WA

International Classification:

G05F 170

US Classification:

323211

Abstract:

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor.

US Patent:

51809630, Jan 19, 1993

Filed:

May 9, 1991

Appl. No.:

7/697673

Inventors:

Mohamed A. El-Sharkawi - Renton WA
George Andexler - Everett WA
Lee I. Silberkleit - Mountlake Terrace WA

Assignee:

Board of Regents of the University of Washington - Seattle WA

International Classification:

G05F 170

US Classification:

323211

Abstract:

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340).