Kazunori Sanada

High-efficiency large-capacity uninterruptible power supply using bidirectional-switch-based NPC multilevel converter

This paper discusses the design and realization of a high-efficiency large-capacity uninterruptible power supply (UPS) using bidirectional-switch-based three-level NPC multilevel power converter. The benefits of three-level topology for low voltage circuits are provided as a motivation for its application in UPS systems. As a result, the novel UPS features higher efficiency and effective size/weight reduction and hence aims to contribute to greening IT facilities with up-to-date power electronics technology.

High-efficiency large-capacity uninterruptible power supply for 3-phase 4-wire power system

This paper discusses design and realization of multilevel uninterruptible power supply (UPS) for 3-phase 4-wire system by using bidirectional-switch-based three-level NPC multilevel power converter. The benefits of three-level topology for low voltage circuits are provided as a motivation for its application in UPS systems. As a result, the novel UPS features higher efficiency and effective size/weight reduction and hence aims to contribute to greening IT facilities with up-to-date power electronics technology.

Development of a small, high-performance, voltage sag compensator COMPACT for high voltage users

The influence of instantaneous voltage drops in the power systems due to lightning have become a significant issue, because manufacturing facilities have become highly sophisticated and intelligent. On the other hand, it may be impossible to completely avoid instantaneous voltage drops in power systems caused by natural phenomena. In order to solve the problem of the voltage drops, this paper presents a high-speed compensation system for the instantaneous voltage drops, COMPACT. This paper describes the COMPACT and confirms its high speed switching performance.

Development of a high-speed high-efficiency voltage sag compensator for high voltage users

This paper proposes a voltage sag compensation system for high voltage users. The proposed system consists of a high-speed mechanical switch with inverter assist function. Additionally, this paper introduces a system high efficiency driving function for high efficiency at light load condition. Operational verification confirms its high-speed change-over performance and its high-efficiency (99.66%).