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The specification for large UPS systems is becoming more standard, and this presentation is an attempt to highlight some of the less obvious points. The subjects chosen for discussion are input requirements of voltage, isolation and harmonics, together with considerations of the battery and the output filter. Areas for potential savings in energy and cost are investigated.
A sine wave, low cost high performance transistorized inverter for the 1 to 6 KVA range was developed and is now being manufactured for comunications and telemetry equipment as well as minicomputers. The design was oriented to the use of easily available components while keeping up reliability and performance. Design criteria for power and control stages are discussed and outcome of enviromental,...
A three-phase variable-frequency inverter using PWM technique has been designed and constructed in which the notch positions are optimized to eliminate a fixed number of harmonics. The control circuitry designed to generate optimum notch positions uses digital techniques contrary to analog modulation techniques used in classical PWM which results in less harmonic distortion in the output waveform...
In this paper, an uninterruptible power supply (UPS) system using a current source inverter is proposed. A single phase and a three phase load commutated current source inverter suitable for this UPS system is presented. The load commutation is achieved by selecting the output filter to maintain a net leading power factor at the inverter output over the operating load range. A steady state analysis...
A new high performance class of line voltage regulators is introduced for application to computer and other communication type loads. It utilizes thyristors to smoothly buck or boost the input voltage to the proper level to compensate for variations in input voltage or load, and maintains plus or minus 1/2% output voltage regulation. Correction to within 5% of normal voltage is possible within 1 cycle...
This paper discribes power converters used and in the research phase in NTT. Nowadays, almost all converters are semiconductor converters. Since they are efficient, small and reliable, they are used in many telecommunication systems. Recent progress in the telecommunication systems enhances the requirement for further converter development. Studies on converters have been continued to minimize size,...
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