Redundant High-Density High-Efficiency Double-Conversion Uninterruptible Power System

This paper presents a novel design for double-conversion uninterruptible power supply (UPS) systems that results in higher power density, higher efficiency, and more flexible parallelism for higher reliability. This design comprises a three-level circuit topology, a custom power semiconductor module, and a cross current sensorless parallel control. The innovative circuit topology results in a UPS with higher efficiency and dramatic size/weight reduction and confirms the advantages of three-level circuits in low-voltage applications. Higher reliability uninterruptible power system using parallel redundant UPS modules employs a novel cross current sensorless control without compromising the performance in comparison with single-module systems. Test results using single- and multiple-module systems confirm the improvement in efficiency and the high performance of this UPS. This novel design is hoped to contribute to greening information technology facilities by realizing high reliability and high efficiency at the same time.