US 5,180,963 A · Optically triggered high voltage switch network and method for switching a high voltage

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). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Claims26

Dependent claims

An optically triggered solid state switch, comprising:

(a) energy storage means, connectable to a voltage source that varies periodically by cycling between positive and negative potentials, for conveying an electrical current and for storing an electrical charge resulting from the electrical current while the voltage source is at one of the positive and negative potentials;
(b) transformer means, connected generally in parallel with the energy storage means, for producing a trigger pulse in response to a pulse of electrical current flowing through the transformer means from the electrical charge stored by the energy means;
(c) light sensitive switch means, connected generally between the energy storage means and the transformer means, for controllably discharging the electrical charge stored by the energy storage means in response to a pulse of light, thereby producing the pulse of electrical current flowing through the transformer means;
and
(d) triggered switch means, connected to the transformer means, for providing a conductive path for an electrical current to flow in respect to the voltage source as the voltage source cycles through substantially a zero potential across the triggered switch means, in response to the trigger pulse.

2 more elements

A solid state switch circuit for selectively controlling an electrical current in respect to a periodically varying high voltage, comprising:

(a) a plurality of solid state switches connected in a series relationship, the plurality of solid state switches each including a gate that is responsive to a trigger signal, causing the solid state switches to conduct the electrical current;
(b) charge storage means for storing an electrical charge used in developing the trigger signal;
(c) triggering means, connected to the charge storage means, for generating the trigger signal for each solid state switch using the electrical charge stored by the charge storage means, in response to a control signal;
and
(d) trigger potential equalizing means, connectable to the periodically varying high voltage, and connected to the plurality of solid state switches and charge storage means, for minimizing a differential voltage across the plurality of solid state switches during part of a cycle of the periodically varying high voltage, the control signal being applied to cause the triggering means to produce the trigger signals only as the periodically varying high voltage cycles through substantially a zero potential across the plurality of solid state switches, so that transient noise is not produced when the plurality of solid state switches begin to conduct electrical current.

2 more elements

Dependencies are inferred from the claim text.

Optically triggered high voltage switch network and method for switching a high voltage

Life of this patent

Optically triggered high voltage switch network and method for switching a high voltage

Life of this patent

Abstract

Claims26