Atomic Energy Council

About: Atomic Energy Council is a government organization based out in Taipei, Taiwan. It is known for research contribution in the topics: Solar cell & Layer (electronics). The organization has 2155 authors who have published 1461 publications receiving 14856 citations.

High-Efficiency DC-DC Converter With High Voltage Gain and Reduced Switch Stress

Abstract: In this paper, a high-efficiency dc-dc converter with high voltage gain and reduced switch stress is proposed. Generally speaking, the utilization of a coupled inductor is useful for raising the step-up ratio of the conventional boost converter. However, the switch surge voltage may be caused by the leakage inductor so that it will result in the requirement of high-voltage-rated devices. In the proposed topology, a three-winding coupled inductor is used for providing a high voltage gain without extreme switch duty-cycle and enhancing the utility rate of magnetic core. Moreover, the energy in the leakage inductor is released directly to the output terminal for avoiding the phenomenon of circulating current and the production of switch surge voltage. In addition, the delay time formed with the cross of primary and secondary currents of the coupled inductor is manipulated to alleviate the reverse-recovery current of the output diode. It can achieve the aim of high-efficiency power conversion. Furthermore, the closed-loop control methodology is utilized in the proposed scheme to overcome the voltage drift problem of the power source under the variation of loads. Some experimental results via an example of a proton exchange membrane fuel cell power source with 250-W nominal rating are given to demonstrate the effectiveness of the proposed power conversion strategy

High-Efficiency Power Conversion System for Kilowatt-Level Stand-Alone Generation Unit With Low Input Voltage

Abstract: This paper mainly focuses on the development of a high-efficiency power conversion system for kilowatt-level stand-alone generation units with a low output voltage, such as photovoltaic modules, fuel cells, and small-scale wind generators, and it aims at having the same output ac voltage, i.e., 110nVrms/ 60nHz as the utility power for the utilization of a stand-alone power supply. This high-efficiency power conversion system includes one high-efficiency high-step-up dc-dc converter and one soft-switching dc-ac current-source inverter. This dc-dc converter is capable of solving the voltage spike problem while the switch is turned off, and it can achieve the objectives of high efficiency and high voltage gain. Because the techniques of soft switching and voltage clamping are used in the dc-ac current-source inverter, the conversion efficiency could greatly be improved. The effectiveness of the designed circuits is verified by experimentation, and the maximum efficiency of the entire high-efficiency power conversion system is over 91% based on the experimental measurements.

Real-Time RFID Indoor Positioning System Based on Kalman-Filter Drift Removal and Heron-Bilateration Location Estimation

Abstract: This paper proposes Kalman-filter drift removal (DR) and Heron-bilateration location estimation (LE) to significantly reduce the received signal strength index (RSSI) drift, localization error, computational complexity, and deployment cost of conventional radio frequency identification (RFID) indoor positioning systems without any sacrifice of localization granularity and accuracy. By means of only one portable RFID reader as the targeted device and only one pair of active RFID tags as the border-deployed landmarks, this paper develops a real-time portable RFID indoor positioning device and cost-effective scalable RFID indoor positioning infrastructure, based on Kalman-filter DR, Heron-bilateration LE, and four novel preprocessing/postprocessing techniques. Experimental results reveal that the proposed Kalman-filter DR method is faster and better to converge the distance measurement (DM) error than conventional probability/statistics in terms of various relative distances under certain RSSI drift effect condition, and the proposed Heron-bilateration LE method is also faster and better to converge the LE error than conventional proximity pattern matching and trilateration in terms of three or more landmarks under certain DM error condition. On the other hand, a portable RFID indoor positioning device is smoothly implemented on an Android smartphone platform attached with a portable Bluetooth-based RFID reader.