High voltage capacitors designed to avoid catastrophic failure modes
A major concern in the operation of high voltage capacitors is the failure mode at end of life. While progress has been made in this area at lower voltages, little has changed for high current capacitors operating above 30 kV in steady state and pulsed power applications. Based on a new development at Maxwell Energy Products, Inc., it is now possible to build capacitors that can operate with a high degree of safety at high voltages. The capacitors reach the normal end of life, while avoiding the catastrophic failures, collateral damage, and unscheduled maintenance, associated with the normal failure mode of today's high voltage capacitors. This paper discusses the problem, capacitor failure modes, capacitor designs and describes a solution to the problem of catastrophic high voltage capacitor failures.
Condition Monitoring of DC-Link Capacitors in Aerospace Drives
This paper proposes a novel online condition monitoring system of dc-link metallized polypropylene capacitors in fault-tolerant drives for aerospace applications. The estimation technique makes use of voltage and current sensors which are already in place for protection and control purposes. The novel aspect of the proposed technique relates to monitoring capacitors in real time while the motor is operational. No external interferences, such as injected signals or special operation of the drive, are required. The condition monitoring system is independent of torque and speed and hence independent of a variation in the load. The condition monitoring system is validated using manual calculations, simulation, low-voltage experimentation, and high-voltage implementation on an aerospace drive.
Automatic classification of TV news articles based on telop character recognition
The purpose of this study is to develop a multimedia database system for TV news video data. TV news video data consist of speech, characters and images. In this study, telop characters are recognized and given to the news articles as indices for classification. At first, telop frames which include telop characters are detected and then the telop characters are extracted and recognized. Through morphological analysis of the recognized telop characters, keywords are extracted which consist of more than two characters. Their keywords are used as indices to classify the TV news articles. We carried out experiments for 30 days of NHK 5 minutes news and obtained 95.4% telop character extraction rate, 81.4% character recognition rate and 83.8% article classification rate. We improved the article classification rate by 43.4% through character recognition improvement from 44.1% to 81.4%.