The analysis of uninterruptible power supplies

In this study, the developments in Uninterruptible Power Systems by the help of research and development studies in power electronics during last few years, various UPS types and working principles are investigated. At the first part, network problems; causes and effects of these problems are stated. The expectations from today?s UPS in order to eliminate these problems are discussed. At the second part UPS types are studied and working principles of different design UPS are examined. At the third part, the basic concept of the thesis, static UPS rectifier, charge, battery, inverter, filter, static manual bypass switch, communication, transformer units are examined and detailed information about these units and electrical parameters are submitted. At the fourth part, the necessary points that should be taken into consideration to provide problem free working conditions between UPS and the generator are studied. Generator power selection during the project for input power factor and input harmonic distortion according to the structure of UPS is discussed. At the fifth part, parallel working principle of UPS aiming to increase reliability as well as increasing the power is studied. Various parallel working principles are explained. At the seventh part, 200kVA 12 pulse rectifier static UPS structure is investigated and card components and their roles are explained. With detailed power analysis and measurements, input output electrical characteristics of an UPS that is used on an imaging center to support an MR equipment is studied. According to measurement results, in order to eliminate input harmonic distortion values that are higher than the international standards, revisions made on UPS and detailed power analysis are discussed. Keywords: Uninterruptible Power Supply, Rectifier, Inverter, Battery, Total Current Harmonic Distortion, PWM (Pulse Width Modulation)