Abstract—This paper describes design considerations and performance analysis of a novel on-line single-phase to three-phase uninterruptible power supply (UPS) with reduced number of switches. The proposed topology uses only 5 active switches reducing the cost of the system compared to the traditional 10-switch topologies. The proposed UPS consists of a single-phase rectifier/charger, a two-leg/three-phase inverter connected to load, battery bank, DC link capacitor and an AC inductor. Detailed circuit operation and analysis as well as simulation results are also presented to verify its feasibility.
Keywords-Uninterruptible Power Supply (UPS); Single-Phase to Three-Phase Conversion; Reduced Switches
Introduction should give a general background and review of the paper or work done by other engineers in the field. It should also contain literature review, objective and scope of the paper. Leave one space between two paragraphs (Do not indent paragraphs). Uninterruptible Power Supplies (UPS’s) are nowadays indispensable equipment in supplying power to critical and sensitive loads. They protect sensitive loads against many existing disturbances in utility network like voltage variations, transients and harmonics. Applications of UPS systems include medical facilities, life supporting systems, data centers, emergency equipment, telecommunications and industrial processing systems.
Ideally, a UPS should deliver clean and uninterrupted power to the load, and at the same time draw sinusoidal, near unity power factor current from input supply. Additionally, static UPS’s must be able to switch between utility and storage batteries as alternate energy sources. This switching must take place in zero or minimum time in order to avoid any malfunctioning of the supplied equipment. Other specifications like high reliability, high efficiency, low EMI and acoustic noise, electric isolation, low maintenance, low cost, weight and size must be also considered in a high performance UPS .
IEC-62040-3 standard classifies UPS’s as
passive-standby, line-interactive and double-conversion (on-line UPS). Each topology has its own characteristics and is used based on the load requirements and the severity and type of network disturbances .
The main advantages of a passive-standby UPS are its design, low cost and small size. The line conditioning is passive which makes this topology fairly robust. On the
1 Department of Electrical Engineering, University of Isfahan, Isfahan, Iran, E-mail: email@example.com
2 Department of Electrical Engineering, University of Isfahan, Isfahan, Iran, firstname.lastname@example.org
other hand, rather long switching time between standby and backup modes is the main disadvantage of this topology.
The line-interactive topology has simple design, fairly high reliability and lower cost, and thus is becoming more attractive as compared to the double-conversion solutions. Since there is...