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Micro-grid is required to be able to operate in the grid-connected mode and the autonomous mode. One of the key functions for such a system is to realize the seamless transition between the two modes. This paper investigates the impact of the islanding detection time on the mode transition of inverter-based micro-grid. First, an inverter-based micro-grid is modeled in the simulation environment of...
This work is concentrated on transfer of power quality disturbances in active distribution network containing small hydro power plants (SHP). Investigations are based on the dispersed synchronized measurements using power quality recorder installed in the two substations connected to the same medium voltage line. Dynamic aspect of SHP work represented by switching on capacitor banks are tracked in...
This paper proposes an algorithm based on the use of the S-transform for time-frequency analysis of the capacitor-switching transients. With no prior knowledge about system parameters, the time-frequency analysis of the voltage and current transient signals due to switched capacitor banks are used to simply but accurately estimate the relative location of the switched capacitor whether it is upstream...
Islanding phenomenon is a problem for Distributed Generator (DG) based networks leading to troubles in voltage and frequency control and other power quality issues. This paper describes the development of a method based on Discrete Wavelet Transform (DWT), in order to detect islanding for DGs. This method detects the islanding state only by evaluating the terminal current of DGs. Hence, different...
Very fast transient over voltages (VFTO) and very fast transient over currents (VFTC) are generated during switching operation of disconnectors in Gas insulated substation (GIS). In this paper the accurate GIS model has been developed and VFTO'S and VFTC'S were estimated at bushing termination using EMTP program. The wavelet analysis of VFTO and VFTC signals have been carried out and frequency spectrum...
Recently, high performance power switching devices realize high performance power converters. High speed turn-on and turn-off switching causes Electro Magnetic Interference (EMI). EMI filters or shieldings will reduce EMI, however, they usually increase the cost and size of power modules. Authors proposed a new method to reduce high-frequency noise at specific frequency bands with modification of...
This paper presents a new view on typical figures of merit for nonlinear distortion evaluation, mainly ACPR, for new wireless communication systems, that are based on time switched signals. Those systems are time switched, either due to the standard specifications as TDD systems, or due to new forms of radio communications as cognitive radio technologies. The most significant differences between conventional...
This paper develops a signal processing, time-frequency analysis-based analytic solution to locate transient capacitor switching disturbances. The flow of transient disturbance energy caused by the capacitor switching is determined by the time and frequency localized phase difference. Cross time-frequency analysis provides time- and frequency-localized phase difference between the transient voltage...
In this paper, we extend the real-time iterative spectrogram inversion method (RTISI) for generating a time-domain audio signal from a magnitude spectrogram such that it can handle changing spectrogram window lengths. For each desired window length, we use a separate buffer structure and synchronize the buffers each time the window length changes. This way, the proposed method helps to improve the...
In this paper we present the design for a fast hopping frequency synthesizer with sub-10 ns switching time capability. The synthesizer utilizes injection-locking to obtain the fast lock time. The measurement results from a prototype design fabricated in 0.13-mum CMOS, shows good agreement with theoretical results. Minimum frequency hopping time at 3.3 GHz is 4 ns while the worst case is 10.02 ns....
Simultaneous switching noise (SSN) is an important issue for the design and test and actual ICs. In particular, SSN that originates from the internal logic circuitry becomes a serious problem as the speed and density of the internal circuit increase. In this paper, an on-chip monitor is proposed to detect potential logic errors in digital circuits due to the presence of SSN. This monitor checks the...
A novel methodology for accurate and efficient static timing analysis is presented in this paper. The methodology is based on finding a frequency domain model for the gates which allows uniform treatment of the gates and interconnects. It is shown that despite the highly nonlinear overall gate model, a frequency domain model of the gate with the model parameters, gate moments, as functions of the...
This paper presents an analytical modeling of ballistic and quasi-ballistic transport, implemented in Verilog-A environment and used for circuit simulation. Our model is based on the Lundstrompsilas approach and uses an expression of the backscattering coefficient given by the flux method. The model takes also into account short channel effects and tales into account the effects of different scattering...
This paper describes a methodology for building a reliable internet core router that considers the vulnerability of its electronic components to single event upset (SEU). It begins with a set of meaningful system level metrics that can be related to product reliability requirements. A specification is then defined that can be effectively used during the system architecture, silicon and software design...
This paper serves the idea of applying joint time-frequency representations for analysis of non-stationary signals in electrical engineering. Main directions of researches are concentrated around Cohenpsilas class of transformation which gives some possibilities of adaptation to analyzed signal by choosing appropriate kernel function. Additionally, novel approach delivered by S-transform is also introduced...
In this paper we present the design for a fast hopping frequency synthesizer with sub-10 ns switching time capability. The synthesizer utilizes injection-locking to obtain the fast lock time. The measurement results from a prototype design fabricated in 0.13-mum CMOS, shows good agreement with theoretical results. Minimum frequency hopping time at 3.3 GHz is 4 ns while the worst case is 10.02 ns....
In this paper we discuss performance results of a novel real-time closed-loop power amplifier (PA) linearization technique that has originally been proposed by Ahmed and Li. The novel approach performs on-the-fly prediction and measurement of the PA AM/AM and AM/PM non-linearity, stores such non-linear characteristics and calculates their inverse functions in order to pre-distort the base-band amplitude...
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