Topic
Equivalent series resistance
About: Equivalent series resistance is a research topic. Over the lifetime, 5335 publications have been published within this topic receiving 83362 citations. The topic is also known as: ESR.
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TL;DR: In this paper, the authors presented a new technique for the evaluation of the parameters of illuminated solar cell with a single diode lumped circuit model and considering the series and shunt resistances.
224 citations
TL;DR: In this paper, a low-cost microcontroller for dc-link electrolytic capacitors in pulsewidth modulation converters is presented, which performs online identification of the capacitor's equivalent series resistance (ESR) to detect the life-cycle status and permit preventive maintenance.
Abstract: A novel life-cycle monitoring and voltage-managing device for dc-link electrolytic capacitors in pulsewidth modulation converters is presented. The system performs online identification of the capacitor's equivalent series resistance (ESR) in order to detect the life-cycle status and permit preventive maintenance. The ESR detection is based on the capacitor's ac losses calculated from voltage/current measurements using a simple low-cost microcontroller. The unit is designed as small printed circuit board located directly at the capacitor's screw terminals in order to simplify the required temperature sensing and to minimize wiring effort. The minimized energy consumption allows a power supply taken out of the capacitor to be tested. Besides life-cycle monitoring, the unit further facilitates energy-efficient voltage balancing for capacitors in series arrangements avoiding any power resistors typically used in balancing circuits. Instead, the unit controls the capacitor voltage by influencing its power consumption. Each individual monitoring unit (one per each power capacitor of the converter) transfers the ESR results to the converter's main controller and receives control commands via a common optoisolated fieldbus. Alternatively, this data transfer is performed using wireless near-field communication leading to a completely autonomous monitoring unit without any wiring for power supply and data transmission.
223 citations
TL;DR: The concept of contact resistivity is discussed briefly and a technique for its measurement is presented in this article, where the relative importance of contact resistance compared to other sources of power loss in a solar cell is determined for a typical contact system.
Abstract: The concept of contact resistivity is discussed briefly and a technique for its measurement is presented. This technique allows for resistive contact material and for the possibility that the semiconductor sheet resistance beneath the contact differs from the semiconductor sheet resistance beside the contact. The test pattern is unique in that the effects of contact resistance are accumulated over the pattern, nearly unencumbered by voltage and current probes which might otherwise influence the current flow. Measurements of contact resistivities for typical solar cell metallizations using this technique are reported to be in the mid 10-6Ω-cm2range. The relative importance of contact resistance compared to other sources of power loss in a solar cell is determined for a typical contact system. Expressions derived in order to make this comparison are useful for evaluating and optimizing a solar cell contact system. Values of series resistance calculated using these expressions are compared with measured values.
222 citations
TL;DR: In this paper, the frequency dependence of forward capacitance-voltage characteristics of Schottky barrier diodes were investigated by considering the series resistance effect, and the peak value of the capacitance was found to vary with series resistance, interface state density and the frequency of the a.c. signal.
Abstract: The frequency dependence of forward capacitance-voltage characteristics of Schottky barrier diodes were investigated by considering the series resistance effect. It is seen that in presence of a series resistance, the capacitance-voltage plot exhibits a peak. The peak value of the capacitance is found to vary with series resistance, interface state density and the frequency of the a.c. signal. The effect of series resistance on the capacitance is found appreciable at higher frequencies when capacitance decreases rapidly with frequency. On the other hand, the conductance of the diode increases with frequency in the high frequency limit. Such a variation in conductance limits the use of well known conductance technique to determine interface state density.
219 citations
TL;DR: In this paper, a general formula based on the concepts of effective resistance and capacitance is developed, which applies for oscillators using active inductors, and the importance of an inductor with very low series resistance is apparent.
Abstract: Frequency synthesizers used in modern telecommunication systems, such as cellular telephones, need to have very low phase noise. Therefore, in the design of high performance frequency synthesizers using Phase Locked Loops (PLL), the Voltage-Controlled Oscillator (VCO) has become a key issue. The trend towards monolithic Integration poses some major challenges. This paper discusses the phase noise aspects of LC-tuned oscillators. A general formula is developed, based on the concepts of effective resistance and capacitance. The formula also applies for oscillators using active inductors. From these results the importance of an inductor with very low series resistance is apparent. To circumvent the technological limits given by an Inductor's series resistance, a presented enhanced LC-tank can be used to make a trade-off between noise and power.
215 citations