Off-line uninterruptible power supply with zero transfer time using integrated magnetics

Abstract

An offline uninterruptible power supply (UPS) or emergency power system with zero transfer time is presented. The principal application is to personal computers and systems. The power transformer, a triport-like transformer, acts as an inverter and as a voltage stabilizer with no external loading coil. It is made with commercial EI scrapless laminations. The battery charging circuit is integrated into the transformer and improves the dynamic output response during line-mode operation. The result is robust, short-circuit-proof equipment with harmonic distortion of lower than 3%, a static output stability better than 1.5%, and a very high reliability.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>