Journal ArticleDOI
Small-Signal Impedance Measurement of Power-Electronics-Based AC Power Systems Using Line-to-Line Current Injection
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TLDR
In this article, an unbalanced line-to-line current injection between two lines of the ac system was proposed to measure the impedance information in the traditional synchronous reference frame d-q model.Abstract:
Naval ships as well as aerospace power systems are incorporating a greater degree of power electronic switching sources and loads. Although these components provide exceptional performance, they are prone to instability due to their high efficiency and constant power characteristics that can exhibit negative impedance nature at certain frequencies. When designing these systems, integrators must consider the impedance versus frequency at an interface (which designates source and load). Stability criteria have been developed in terms of source and load impedances for both dc and ac systems, and it is often helpful to have techniques for impedance measurement. For dc systems, the measurement techniques have been well established. This paper introduces a new method of impedance measurement for three-phase ac systems. By injecting an unbalanced line-to-line current between two lines of the ac system, all impedance information in the traditional synchronous reference frame d-q model can be determined. For medium-voltage systems, the proposed technique is simpler and less costly than having an injection circuit for each phase. Since the current injection is between only two phase lines, the proposed measurement device can be used for both ac and dc interfaces. Simulation and laboratory measurements demonstrate the effectiveness of this new technique.read more
Citations
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Journal ArticleDOI
Analysis of D-Q Small-Signal Impedance of Grid-Tied Inverters
TL;DR: In this article, the small-signal impedance of three-phase grid-tied inverters with feedback control and phase-locked loop (PLL) in the synchronous reference ( d-q ) frame is analyzed.
Journal ArticleDOI
Adaptive Droop Control Applied to Voltage-Source Inverters Operating in Grid-Connected and Islanded Modes
TL;DR: A novel control for voltage-source inverters with the capability to flexibly operate in grid-connected and islanded modes based on the droop method, which uses some estimated grid parameters such as the voltage and frequency and the magnitude and angle of the grid impedance.
Journal ArticleDOI
Small-Signal Stability Analysis of Three-Phase AC Systems in the Presence of Constant Power Loads Based on Measured d-q Frame Impedances
TL;DR: In this paper, the authors investigated the small-signal stability of a three-phase ac system using measured d-q frame impedances, and showed that the stability at the ac interface can be easily and readily predicted using the measured impedances and the generalized Nyquist stability criterion (GNC).
Journal ArticleDOI
A Modified Sequence-Domain Impedance Definition and Its Equivalence to the dq-Domain Impedance Definition for the Stability Analysis of AC Power Electronic Systems
TL;DR: It is shown that if a system is incorrectly assumed to be MFD, this will lead to an erroneous or ambiguous estimation of the equivalent impedance, and with this definition the stability estimates obtained with the generalized Nyquist criterion become equivalent in both domains.
Definitions and Applications of Dynamic Average Models for Analysis of Power Systems IEEE Task Force on Dynamic Average Modeling, Working Group on Modeling and Analysis of System Transients Using Digital Programs, Transmission and Distribution Committee, IEEE Power and Energy Society
S. Chiniforoosh,J. Jatskevich,Amirnaser Yazdani,Vijay K. Sood,V. Dinavahi,J. A. Martinez,A. Ramirez +6 more
TL;DR: An overview of dynamic average-value modeling techniques for representing static switching converters for the system-level studies and desirable properties of averaged models for conducting large-Signal time-domain transient studies and small-signal frequency-domain analysis for control design tasks are discussed.
References
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Journal ArticleDOI
Constant power loads and negative impedance instability in automotive systems: definition, modeling, stability, and control of power electronic converters and motor drives
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Journal ArticleDOI
A method of defining the load impedance specification for a stable distributed power system
TL;DR: In this paper, a forbidden region for the polar plot of the ratio of impedances at the interface between two cascaded power subsystems is determined, and a method of transforming the forbidden region into a load impedance specification for a given source impedance is developed.