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Researches to control water content of Polymer Electrolyte Membrane(PEM) are actively performed for increasing performance & durability of Fuel cell. This Research to control water content focused on measurement of PEM impedance. In this paper, The measurement system of PEM Impedance based on AC impedance method is proposed. Bi-directional DC/DC converter is designed to measurement of PEM impedance...
The complexity of electrical energy nets in modern cars is increasing rapidly due to the rising number of dc-dc converters and motor controllers. Multi-converter systems may lead to negative impedance instability that must be avoided in the automotive energy net under all circumstances, including faulty conditions such as a failure of batteries or other energy storage devices. Many stability criteria...
In the field of wireless power transfer technologies, the improvement of transmission efficiency is one of the critical issues. It is important to understand how much power loss is imposed in which areas of a wireless power transfer system in the development phase. Since the transmission characteristics change according to ambient conditions, a measuring instrument capable of observing electric power...
Passive components, in particular capacitors, are widely used in power electronics, especially in EMC filters. Their impedance variation with respect to operating conditions (frequency, temperature, operating voltage) is very significant and shouldn't be neglected. In this paper, we aim to characterize the influence of bias voltage variations on capacitor parameters (C and ESR) over a wide frequency...
Trends in high performance computing (HPC) systems point to ever-decreasing power delivery network (PDN) impedances. While there is no particular theoretical minimum impedance, practical limitations present boundaries which will be difficult to exceed. In this paper, we explore specifically the practical limitations of the printed circuit board (PCB) portion of the PDN, concluding that useful implementations...
A dsPIC (Digital Signal Peripheral Interface Controller) based impedance measuring system was developed and implemented. The system measures the impedance's amplitude and phase at the desired frequency using a sine-fitting algorithm running on the dsPIC and the results are sent to a personal computer using an USB or RS-232 connection. The measurement results are also shown in an LCD included in the...
This paper investigates a new distance protection principle for a transmission line compensated with 3-phase capacitor banks installed in the middle of the line. Series Capacitors (SCs) equipped with Metal-Oxide Varistors (MOVs), when set on a transmission line, create certain problems for its protective devices. Direct application of the classic distance protection (designed for traditional lines)...
This paper describes the high-frequency characteristics of a multilayered planar transformer consisting of two planar coils and Co-Fe amorphous magnetic films. The parameters of transformer operation obtained by finite element method (FEM) calculations are compared with measured values. The analysis shows that characteristic evaluation is useful for a simple understanding of the operation of a transformer...
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