A new approach to improve dynamic characteristics of digitally controlled buck-boost dc-dc converter

This paper presents a new digital control buck-boost dc-dc converter with bias model to improve dynamic characteristics. The buck-boost converter needs to respond appropriately to changing input voltage and load change with wide input voltage. This approach makes adjustment to the bias value by input voltage and output current. As a result, it is revealed that not only the dynamic characteristics but also static characteristics can be improved and it is effective for wide range input voltage.2010 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM 2010) : Pisa, Italy, 2010.06.14-2010.06.1

Multipurpose Strategy for Energy Storage System Based on Capital Asset Pricing Model With Ensemble Approach

In this paper, we present a multipurpose operation strategy for the efficient distribution of power to multiple power services from a single battery energy storage system (BESS). The proposed operation strategy uses a modern portfolio theory of financial engineering known as the capital asset pricing model to determine the allocation of BESS discharge power. Using this strategy, it is possible to quantitatively evaluate the expected return and risk in BESS operation and achieve the maximum expected return for the selected acceptable risk. Further, the predictability of the expected return is improved by applying the ensemble approach to the estimation model of the expected return. A one-year long performance test was conducted at the Japan Electric Power Exchange using the proposed operation strategy. A mean absolute error of approximately 2.0% between the expected return of the proposed strategy and the actual return was obtained, confirming the accuracy of the proposed strategy

Developing of higher voltage direct-current power-feeding prototype system

High efficiency power feeding systems are effective solutions for reducing ICT power consumption of ICT equipment, such as routers and servers, or high efficiency cooling systems. We developed a higher voltage direct current (HVDC) power feeding system prototype. This system is composed of a rectifier, power distribution cabinet, batteries, and ICT equipment. The configuration is similar to a -48 V DC power supply system. The output of the rectifier is 100 kW, and the output voltage is 401.4 V. We describe the advantage of an HVDC power feeding system and show that its basic characteristics are stable.INTELEC 2009 - 2009 International Telecommunications Energy Conference : Incheon, South Korea, 2009.10.18-2009.10.2