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Output impedance
About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.
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TL;DR: In this article, a novel A-source impedance network is proposed, which uses an autotransformer for realizing converters for any application that demand a very high dc voltage gain, and it utilizes a minimal turns ratio compared to other magnetically coupled impedance source networks to attain a high voltage gain.
Abstract: A novel A-source impedance network is proposed in this letter. The A-source impedance network uses an autotransformer for realizing converters for any application that demand a very high dc voltage gain. The network utilizes a minimal turns ratio compared to other magnetically coupled impedance source networks to attain a high voltage gain. In addition, the proposed converter draws a continuous current from the source, and hence it is suitable for many types of renewable energy sources. The derived network expressions and theoretical analysis are finally validated experimentally with an example single-switch 400-W dc–dc converter. For the closed-loop control design and stability assessment, a small signal model and its analysis of the proposed network are also presented in brief.
179 citations
TL;DR: It is shown that there exists a universal droop control principle for inverters with output impedance having a phase angle between -(π/2) rad and (π/ 2) rad, and the robust droop controller recently proposed in the literature for R-inverters actually provides one way to implement such a universalDroop controller that can be applied to all practical inverters without the need of knowing the impedance angle.
Abstract: Droop control is a well-known strategy for the parallel operation of inverters. However, the droop control strategy changes its form for inverters with different types of output impedance, and so far, it is impossible to operate inverters with inductive and capacitive output impedances in parallel. In this paper, it is shown that there exists a universal droop control principle for inverters with output impedance having a phase angle between $- ({\pi }/{2})$ rad and $({\pi }/{2})$ rad. It takes the form of the droop control for inverters with resistive output impedance ( $R$ -inverters). Hence, the robust droop controller recently proposed in the literature for $R$ -inverters actually provides one way to implement such a universal droop controller that can be applied to all practical inverters without the need of knowing the impedance angle. The small-signal stability of an inverter equipped with the universal droop controller is analyzed, and it is shown to be stable when the phase angle of the output impedance changes from $- ({\pi }/{2})$ rad to $({\pi }/{2})$ rad. Both real-time simulation results and experimental results from a test rig consisting of an $R$ -inverter, an $L$ -inverter, and a $C$ -inverter operated in parallel are presented to validate the proposed strategy.
178 citations
TL;DR: In this paper, the authors show that electrode polarization impedance can indeed influence the measurements and that also other phenomena such as negative sensitivity regions, separate current paths and common-mode signals may seriously spoil the measured data.
Abstract: Tetrapolar electrode systems are commonly used for impedance measurements on biomaterials and other ionic conductors. They are generally believed to be immune to the influence from electrode polarization impedance and little can be found in the literature about possible pitfalls or sources of error when using tetrapolar electrode systems. In this paper we show that electrode polarization impedance can indeed influence the measurements and that also other phenomena such as negative sensitivity regions, separate current paths and common-mode signals may seriously spoil the measured data.
176 citations
TL;DR: Through the control of the power converter and duty-cycle perturbation, the ac impedance of the battery can be determined and the obtained impedance data are utilized for online state-of-charge estimation of lithium-ion batteries.
Abstract: This paper presents a simple online impedance measurement method for electrochemical batteries, including lithium-ion, lead-acid, and nickel–metal-hydride chemistries By using the proposed online impedance measurement method, there is no need to disconnect the battery from the system or to interrupt system operation, and there is no need to add ac signal injection circuits, costly response measurement, and analysis circuits/devices In practical battery-powered systems, a power converter is usually used to interface the battery with the load for voltage/current regulation purposes In this paper, through the control of the power converter and duty-cycle perturbation, the ac impedance of the battery can be determined The proposed method provides a low-cost and practical solution for the online measurement of the ac impedance of batteries Moreover, the proposed method can be either continuously or periodically performed without interrupting the normal operation of the battery system and the power converter In addition, this paper provides an example where the obtained impedance data are utilized for online state-of-charge estimation of lithium-ion batteries The proposed online impedance measurement method is validated by experiments conducted on a 26-Ah 18650-size lithium-ion battery interfaced to the load via a bidirectional dc–dc boost/buck converter
172 citations
TL;DR: In this article, the authors introduce a method of implementing any arbitrary impedance, using a digital signal processor, on a resonant simply supported beam using a PZT transducer.
Abstract: Piezoelectric transducer (PZT) patches may be attached to structures to reduce vibration. The PZT patches essentially convert vibrational mechanical energy to electrical energy. The electrical energy can be dissipated via an electrical impedance. The authors introduce a method of implementing any arbitrary impedance, using a digital signal processor. The ‘synthetic impedance’ is demonstrated on a resonant simply supported beam.
172 citations