A novel scheme for obtaining the fundamental-frequency positive-sequence grid voltage vector based on a generalization of delayed signal cancellation method is proposed in this paper. The technique implemented by sampling and storing instantaneous αβ vector. mathematical transformation then through which current vectors are combined. It shown that has unity gain vector, while its equal to zero some chosen components. Cascaded transformations can be used eliminating negative-sequence as well...

Second order generalized integrators (SOGI) have been proposed to obtain zero steady-state error using stationary frames in grid-converters applied active rectifiers, filters, uninterruptible power supplies and distributed generation. These also included algorithms of grid synchronization, detection sequences, harmonic compensation, etc. Due all these are implemented over digital processors, it is very important make a correct discretization optimize their behaviour. This work focused this...

This paper proposes a grid impedance monitoring system for distributed power generation electronic interfaces. The estimates the equivalent and voltage source from measurements performed at point of common coupling. estimation algorithm is based on recursive least-squares implemented in complex field. Simultaneously, evaluates quality estimation, minimizing its influence detecting islanding situations. proposed performance has been evaluated under experimental testing.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> As the number of wind power applications with electronic interfaces in grid increases, it is becoming unacceptable to disconnect generating units every time disturbances occur, especially under voltage dips, as was a common practice past. Keeping converter online during unbalanced voltage, and guaranteeing actual standards connected grid, very critical issue. From these goals, design robust...

New energy concepts such as distributed power generation systems (DPGSs) are changing the face of electric distribution and transmission. Power electronics researchers try to apply new electronic controller solutions with capacity implementing more complex control algorithms combined internal high-speed communication interfaces. Thus, it is possible monitor, store, transfer a large number variables that can be sent online local or remote hosts in order take set points different units. With...

In this paper, two methods for determining the fundamental frequency and harmonic positive- negative-sequence components of three-phase signals are investigated. Many aspects space-vector discrete Fourier transform generalized delayed signal cancellation (GDSC) such as response time different possible implementations, adaptation schemes, stability recursive implementation, rounding error effects discussed. A new design procedure GDSC transformations is presented. New indices characterizing...

LCL filters are commonly used to connect voltage-sourced converters (VSCs) the grid. This type of filter is cheaper than a single inductor for same current total harmonic distortion (THD), but it generates resonance problems if no active or passive damping method applied. Active methods becoming popular in literature because they improve efficiency, sometimes difficult implement and additional measurements required. paper proposes an VSCs connected weak grids, which based on making open-loop...

Transmission system operators (TSOs) are increasingly requesting frequency support, reactive power compensation, and grid-forming capability to plants interfaced by converters. In these plants, a large number of converters is operated in parallel all them should be adequately coordinated provide services. For that purpose, the virtual synchronous machine (VSM) control technique commonly adopted. However, dynamic characteristics whole plant depend on connected, their size, parameters,...

The objective of this paper is to analyse the influence a non-ideal grid over hysteresis controllers converters connected through both L and LCL filters. will describe different possible configurations in cases, analysing effect general R-L grid. Limit values for inductance resistance are given structure. In case connection, analysis overview important issues such as active damping, switching behaviour giving limits stability function impedance value.

This article presents a systematic robust current control design approach for three-phase voltage-source converters. Robustness is guaranteed by combining intrinsic passive properties of the impedance uncertainty at point common coupling together with stability results from passivity-based theory. ensures against typical sources mid and high frequencies, such as cable resonances or other converters interaction, significant less conservative performances than obtained traditional The uses...

Losses and maximum temperature are important indicators of the health status medium-frequency magnetic components. Both losses very difficult to obtain/estimate due high complexity, change in core with respect average temperature, or variation windings derived from construction litz wire high-frequency effects. This article proposes use a real-time estimator, based on artificial neural networks trained finite element method simulations capable predicting an error less than 2% all cases both...

LCL-filter based grid-tie inverters require damping for current-loop stability.There are only software modifications in active damping, whereas resistors added passive damping.Although incurs additional losses, it is widely used because of its simplicity.This article considers the medium-voltage parallel wind turbines.Due to cost reasons, minimal changes allowed and no extra sensors can be used.The procedure must robust against line-inductance variations weak grids.Doubleupdate mode needed...

In contemporary electrical distribution systems, multiple parallel inverters collaborate to form an advanced power network, which poses stability challenges. Small-signal analysis is a fundamental method for characterizing interactions between system impedances. three-phase ac assessment involves examining the source-to-load impedance ratio in complex <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> plane using Generalized Nyquist...

In many of the recent array ultrasonic applications, acquisition rate is a crucial issue. Many those applications are even impractical due to sequential nature ultrasound systems scanning. Obviously, one way increasing this use multi-mode operation. This paper introduces basic aspects operation based on pulse compression techniques by means binary sequences in BPSK modulation scheme, and advantages Golay sequences, with respect m-sequences, mostly used works. Finally, some results...

The aim of this paper is to propose a current control VSCs connected the grid through an LCL-filter. proposed algorithm controls using only two sensors. Other variables are obtained with state estimator, and possible disturbances system attenuated active damping. has been proved for different disturbances, such as temporal variations in components model perturbations grid, also linear nonlinear models.

Accurate phase information is crucial for most of modern power electronic systems such as VSC connected to the grid. In this paper, it proposed an algorithm software phase-locked loop (SPLL) obtain and frequency grid voltage. This based in on-line separation voltage sequences (DSC), a discrete traditional PLL. A criterion tune SPLL constants from PLL linearized model discussed. The response evaluated different disturbances parameters. Besides, through L filter with obtained paper has been...

Voltage controlled voltage source converters (VCVSC) and current (CCVSC) have gained importance within distributed power generation systems equipment for quality improvement. The control action is susceptible to fall in saturation under disturbance transients or case of poor tuning. use existing techniques vector variables, such as three-phase current, distorts the reference waveforms unbalanced conditions regardless used frames--stationary (αβ-axis) synchronous (dq-axis). These harmonics...

The rise of distributed power generation systems comes along with an energy storage increment. Moreover, the expensiveness batteries and dc capacitors generate interest on extending their lifetime, directly related current ripple. Unlike other multifrequency approaches, in this paper, harmonic reference currents are calculated to reduce low-frequency active fluctuations, obtaining superior results contrast existing techniques effectively alleviating associated harmful effects. As not set...

This article analyzes the possibility to employ artificial neural networks (ANNs) for thermal modeling of magnetic components, with special emphasis on medium frequency transformers (MFTs). The objective is obtain an MFT model that can be easily used in multivariable optimizations and automated design power electronics converters, when it necessary rapidly explore complete space, optimizing system from point view efficiency density, without losing accuracy. accomplished using low...