Keiji Akamatsu

Operation analysis of high efficiency grid connected bi-directional power conversion system for various storage battery systems with bi-directional switch circuit topology

In recent years, there is an increasing demand for various types of storage battery systems, such as home battery systems, V2H(Vehicle-to-Home)/V2G(Vehicle-to-Grid) systems, and UPS systems. Performance requirements for the power conversion system within these storage battery systems are small size, light weight and high efficiency. We propose a new power conversion system so called the GAP-D3 converter that is a bi-directional power control system, comprising of a bi-directional switch circuit topology with natural commutation switching mode. This paper describes the features of GAP-D3 converter including this new current compensation control with simulation and experimental results.

Application of the time-frequency analysis using wavelet transform to harmonics analysis in the power conversion systems

In recent years, next generation power semiconductor devices have attracted attention such as SiC device, GaN device and so on. By applying next generation power semiconductor devices to power conversion systems, its operation frequency becomes higher. As the results, small size, light weight and high efficiency of the power conversion system can be realized. However, when operation frequency becomes high, harmonics issue is caused. Therefore, harmonics analysis of the power conversion system is very important. In order to analyze the harmonics in detail, this paper proposes Wavelet transform analysis as the time-frequency analysis. This paper describes the feature of the Wavelet transform from experimental results.