Patent
1994-06-08
1997-10-14
Davis, George B.
395 20, 395 21, 395 23, H02M 3335, H04N 521, G06F 1500
Patent
active
056779984
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to apparatus for pulsed electrical power circuitry, including pulsed power supplies.
2. Discussion of Prior Art
Pulsed power supplies are employed to drive various high power loads such as lasers, especially gas discharge lasers such as copper vapour lasers (CVL).
The modulator switching element often employed in such a circuit is a thyratron. The load in the case of a gas discharge laser such as a CVL consists of a longitudinal discharge whose effective electrical impedance behaviour is highly non-linear, making impedance matching to the modulator impossible over a full operating cycle. The mismatch causes some of the energy incident at the load to be reflected back to the modulator where, in most cases, it causes the voltage across the thyratron (vak) to reverse polarity. Such reversals are usually accompanied by thyratron damage. A high proportion of CVL running costs are in thyratron replacements. Two factors which reduce the thyratron lifetime significantly are the inverse peak value and the reversal rate of vak. These in turn, depend upon discharge conditions.
Many methods which aim to identify the laser discharge conditions which severely stress the thyratron have been tried but have been found to be unsatisfactory in one form or another.
SUMMARY OF THE INVENTION
The purpose of the present invention is to monitor the current or voltage characteristic in a pulsed power circuit, so that conditions stressful to a component in the circuit, e.g. a thyratron, may be reliably detected to protect the component.
According to the present invention there is provided apparatus for pulsed electrical power circuitry including a pulsed power supply circuit, monitor means for monitoring a voltage or current characteristic within the supply circuit and an artificial neural network trained to identify whether the detected characteristic is acceptable or harmful and adapted to produce an output accordingly.
Voltage monitoring may be carried out using a known probe, which may, if required convert the monitored voltage into a signal proportional to the voltage but stepped down in magnitude.
Current monitoring may be carried out using a known device, e.g. a Rogowski coil (incorporating an integrator) or a resistor in series with the component being monitored, which produces an output proportional to the current.
The neural network approach used in this invention is not only able to identify stressful conditions quickly, but, if other stressful conditions develop, or a different type of load, e.g. a new laser head, is installed, the network can be retrained to identify the new undesirable conditions. In addition, a single neural network can be used to scan sequentially each of the loads, e.g. lasers, in an array.
The invention is simple enough to enable "user friendly" programs to be written to enable a person unskilled in computer systems (but experienced in the specific pulsed power circuit behaviour) to teach the neural network to give the appropriate output response to the applied waveform. These outputs can range from simply providing an alert e.g. by an audible sound or a visible indicator light, to automatically altering the power circuit conditions to reduce component stress. If a false alarm is generated or a new stressful condition identified, the operator can re-train the network. Although the invention is simple and inexpensive, it may facilitate automatic control of complex processes.
The apparatus according to the present invention may comprise a power supply for a high power laser, e.g. a gas discharge, e.g. metal vapour laser such as a copper vapour laser (CVL) or a plurality of such lasers. The characteristic monitored by the monitor means may be the voltage waveform across a thyratron or other switching element employed in the pulsed power circuit.
The neural network may be trained by storage of a set of signals representing a variety of monitored sample waveforms together with designations as to whether the sample wa
REFERENCES:
patent: 5003490 (1991-03-01), Castelaz et al.
patent: 5052043 (1991-09-01), Gaborski
patent: 5092343 (1992-03-01), Spitzer et al.
patent: 5146602 (1992-09-01), Holler et al.
patent: 5251626 (1993-10-01), Nickolls et al.
patent: 5258903 (1993-11-01), Rodriquez-Cavazos
patent: 5283418 (1994-02-01), Bellows et al.
patent: 5345557 (1994-09-01), Wendt
patent: 5371835 (1994-12-01), Akamatsu et al.
patent: 5440566 (1995-08-01), Spence et al.
Ebron et al, "A Neural Network Approach to the Detection of Incipient Faults on Power Distribution Feeders", IEEE 1990.
Danials et al, "Power Quality Monitoring Using Neural Networks", IEEE Applications of Neural Networks to Power Systems, 1991.
Jayaraman et al, "Neural Net Based Correction of Power System Distortion Caused by Switching Power Supplies," IEEE Applications of Neural Networks to Power Systems, 1991.
British Nuclear Fuels PLC
Davis George B.
LandOfFree
Apparatus for pulsed electrical circuitry does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for pulsed electrical circuitry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for pulsed electrical circuitry will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1560605