Design and Implementation of Stand-by UPS System with PWM Controller, Automatic Voltage Regulator Section and Charging Section

Abstract

Power distortions such as power interruptions, voltage sags and swells, voltage spikes, and voltage harmonics can cause severe impacts on sensitive loads in the electrical systems. Uninterruptible Power Supply (UPS) systems are used to provide uninterrupted, reliable, and high quality power for these sensitive loads. Applications of UPS systems include medical facilities, life supporting systems, data storage and computer systems, emergency equipment, telecommunications, industrial processing, and on-line management systems. The UPS systems are especially required in places where power outages and fluctuations occur frequently. An UPS provides a backup power circuitry to supply systems when a power outage occurs.The project aims to design and construct a 500 VA / 12 V stand-by UPS system with the push-pull inverter and centre tapped main transformer having the different sections such as, Oscillator Section, PWM Controller Output Section, Automatic Voltage Regulator (AVR) Section, Low Voltage Cut Section, High Voltage Cut Section, Charging Section, Changeover Section, No Load Shutdown Section, Low-Battery Shutdown Section, and Overload Shutdown Section.When the supply voltage is available, an AVR section regulates any ups and downs in the AC mains supply input and sends a regulated clean AC output to its output socket. When supply voltage goes below or above the set range or the supply voltage gets cut o the changeover of supply to the load from AC supply to battery takes place.