Topic
Electrical impedance
About: Electrical impedance is a research topic. Over the lifetime, 36015 publications have been published within this topic receiving 371891 citations. The topic is also known as: electrical impedance & complex impedance.
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TL;DR: In this paper, a wave propagation model was developed to model the standing wave pattern in an impedance tube, and the acoustic impedance of a test specimen was calculated from a best fit of this model to pressure measurements obtained along the impedance tube centerline.
75 citations
TL;DR: In this article, an impedance model-based frequency domain analysis was employed to detect subsynchronous resonances (SSRs) in Type-3 wind farms with TCSC.
Abstract: This paper employs impedance model-based frequency domain analysis to detect subsynchronous resonances (SSRs) in Type-3 wind farms with thyristor-controlled series capacitor (TCSC). The contributions of this paper are 1)the derivation of dynamic phasor-based TCSC impedance model and 2)the application of such an impedance model in Type-3 wind energy systems for SSR analysis. Impedance models for TCSC with constant firing angle control and impedance control are derived in this paper. With the derived impedance models, Nyquist stability criterion is applied to compare SSR stability in Type-3 wind farm with TCSC or with fixed capacitor compensation. This paper employs analytical models to demonstrate TCSCs capability in avoiding SSR in Type-3 wind generator interconnection systems. The analytical results obtained through impedance models are validated by detail model-based (with thyristor switch-modeled) time-domain simulation in MATLAB/SimPowerSystems.
75 citations
TL;DR: In this paper, the proper equivalent interface circuit of a piezoelectric material below ultrasonic frequency range is developed and analyzed incorporating a voltage source and a capacitor theoretically and experimentally.
Abstract: The proper equivalent interface circuit of a piezoelectric material below ultrasonic frequency range is developed and analyzed incorporating a voltage source and a capacitor theoretically and experimentally. The emphasis is placed on the physical connection between a capacitor and a voltage source. The first model considered is of a capacitor connected in series with a voltage source. The second model consists of a capacitor connected in parallel with a voltage source. This paper presents the analyses of these two different circuit models for a piezoceramic by discussing the electric impedance and phase angle of a piezoceramic theoretically and experimentally and determines the best-fit model of a PZT to use for structural vibration applications.
75 citations
Patent•
TDK1
TL;DR: In this article, a line-shaped or belt-shaped first conductor with an electrically half length of a wave-length of a first resonant frequency, a feed point 12 to which an end of the first conductor is connected, a plate-shaped second conductor 13 on which the feed point is located and on which another end of one conductor is grounded.
Abstract: In an antenna device 10 including a line-shaped or belt-shaped first conductor 11 having an electrically half length of a wave-length of a first resonant frequency, a feed point 12 to which an end of the first conductor is connected, a plate-shaped second conductor 13 on which the feed point is located and on which another end of the first conductor is grounded, an impedance element 14 is loaded halfway on the first conductor and which varies the first resonant frequency, a second resonant frequency, or both the first resonant frequency and the second resonant frequency. Accordingly, a compact antenna device 10 can therefore be constituted so that an impedance matching between the first conductor 11 and the feed point 12 may be readily obtained. In addition, the antenna device 10 can be commonly used with respect to a multi-frequency operation.
75 citations
TL;DR: In this paper, a detailed methodology for the accurate evaluation of high-frequency impedance of graphene-based structures relevant to on-chip interconnect and inductor applications is presented, where the effects of electric field variation within a mean free path and current dependency on the nonlocal electric field are taken into account to accurately capture the highfrequency behavior of graphene ribbons.
Abstract: This paper presents the first detailed methodology for the accurate evaluation of high-frequency impedance of graphene-based structures relevant to on-chip interconnect and inductor applications. Going beyond the simplifying assumptions of Ohm's law, the effects of electric-field variation within a mean free path and current dependency on the nonlocal electric-field are taken into account to accurately capture the high-frequency behavior of graphene ribbons (GRs). At the same time, a simplified approach that may be adopted at lower frequencies is also explained. Starting from the basic Boltzmann equation and combining with the unique dispersion relation for graphene in its hexagonal Brillouin zone, the current density across the GR structure is derived. First, a semi-infinite slab of GR is analyzed using the theory of Fourier integrals, which is followed by the development of a rigorous methodology for practical finite structures based on a self-consistent numerical calculation of the derived current density using the Green's function approach.
75 citations