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Leonardo Rodrigues Limongi

Bio: Leonardo Rodrigues Limongi is an academic researcher from Federal University of Pernambuco. The author has contributed to research in topics: AC power & Inverter. The author has an hindex of 13, co-authored 53 publications receiving 1099 citations. Previous affiliations of Leonardo Rodrigues Limongi include Universidade de Pernambuco & Polytechnic University of Turin.


Papers
More filters
Journal ArticleDOI
04 Jul 2010
TL;DR: In this article, a single-phase inverter for distributed generation systems requiring power quality features, such as harmonic and reactive power compensation for grid-connected operation, is proposed, where the inverter controls the active power flow from the renewable energy source to the grid and also performs the nonlinear load current harmonic compensation keeping the grid current almost sinusoidal.
Abstract: Power electronic converters are commonly used for interfacing distributed generation systems to the electrical power network. This paper deals with a single-phase inverter for distributed generation systems requiring power quality features, such as harmonic and reactive power compensation for grid-connected operation. The idea is to integrate the DG unit functions with shunt active power filter capabilities. With the proposed approach, the inverter controls the active power flow from the renewable energy source to the grid and also performs the non-linear load current harmonic compensation keeping the grid current almost sinusoidal. The control scheme employs a current reference generator based on Sinusoidal Signal Integrator (SSI) and Instantaneous Reactive Power (IRP) theory together with a repetitive current controller. Experimental results obtained on a 4 kVA inverter prototype demonstrate the feasibility of the proposed solution.

301 citations

Journal ArticleDOI
TL;DR: The paper is about comparing the performance of digital signal processor-based current controllers for three-phase active power filters.
Abstract: The paper is about comparing the performance of digital signal processor-based current controllers for three-phase active power filters.

131 citations

Proceedings ArticleDOI
02 Apr 2007
TL;DR: In this article, the authors present an analysis and comparison of phase-locked loop techniques used in grid utility applications to find the voltage vector angle generated from the supply voltages, and compare the performance of different PLL-based techniques for utility applications.
Abstract: This paper presents an analysis and comparison of phase locked loop techniques used in grid utility applications to find the voltage vector angle generated from the supply voltages. The phase locked loop (PLL) has a wide range of applications as distributed generation (DG), flexible AC transmission systems (FACTS), static VAR compensators, cycloconverters, active power filters (APF's) and others systems connected to the utility. The performance of these systems in grid connected applications is strongly influenced by the adopted PLL strategy. For this reason, the goal of the proposed paper is to present a comparison of different PLL-based techniques for utility applications to indicate the appropriate solution dedicated to a specific application. The criteria to compare the phase locked loops techniques is the performance under distorted and unbalanced supply voltages.

123 citations

Journal ArticleDOI
TL;DR: In this article, a new stationary frame control scheme for three-phase PWM rectifiers operating under unbalanced voltage dips conditions is proposed, which regulates the instantaneous active power at the converter poles to minimize the harmonics of the input currents and the output voltage ripple.
Abstract: A new stationary frame control scheme for three-phase pulsewidth-modulation (PWM) rectifiers operating under unbalanced voltage dips conditions is proposed in this paper The proposed control scheme regulates the instantaneous active power at the converter poles to minimize the harmonics of the input currents and the output voltage ripple This paper's novelty is the development of a new current-reference generator implemented directly in stationary reference frame This allows using proportional sinusoidal signal integrator (P-SSI) controllers for simultaneous compensation of both positive and negative current sequence components No phase-locked loop (PLL) strategies and coordinate transformations are needed for the proposed current-reference generator Experimental results are presented for a 20-kV A alternative current (ac)/direct current (dc) converter prototype to demonstrate the effectiveness of the proposed control scheme A comparison with two other existing control techniques is also performed Fast dynamic performance with small dc-link voltage ripple and input sinusoidal currents are obtained with this control scheme, even under severe voltage dips operating conditions

95 citations

Journal ArticleDOI
TL;DR: Simulation and experimental results show the superior performance of the proposed GMPPT algorithm, in comparison to the state-of-art algorithms, in terms of tracking time, energy loss, and total voltage track during the search for the GMPP.
Abstract: In string photovoltaic (PV) systems, the power–voltage ( P – V ) characteristic under partial shading conditions (PSC) displays multiple peaks requiring global maximum power point (GMPP) tracking (GMPPT) algorithms to identify the PV array GMPP. Several GMPPT algorithms scan wide voltage tracks to detect the GMPP, even larger than a P – V curve full scan. Moreover, many algorithms have been tested only for simple PSC that lead to three well distinct peaks at most. This paper initially presents a trapezoidal area, called the maximum power trapezium (MPT), in the P – V plane that contains all possible GMPPs for any PSC. Using the MPT and information about the minimum voltage difference between adjacent local peaks, a GMPPT algorithm is proposed, which tracks the GMPP of a string PV array under any severe PSC reducing its voltage track and so its tracking time. Simulation and experimental results show the superior performance of the proposed algorithm, in comparison to the state-of-art algorithms, in terms of tracking time, energy loss, and total voltage track during the search for the GMPP.

90 citations


Cited by
More filters
01 Sep 2010

2,148 citations

Journal ArticleDOI
TL;DR: A phase-locked loop (PLL) is a nonlinear negative feedback control system that synchronizes its output in frequency as well as in phase with its input PLLs are now widely used for the synchronization of power-electronics-based converters and also for monitoring and control purposes in different engineering fields as mentioned in this paper.
Abstract: A phase-locked loop (PLL) is a nonlinear negative-feedback control system that synchronizes its output in frequency as well as in phase with its input PLLs are now widely used for the synchronization of power-electronics-based converters and also for monitoring and control purposes in different engineering fields In recent years, there have been many attempts to design more advanced PLLs for three-phase applications The aim of this paper is to provide overviews of these attempts, which can be very useful for engineers and academic researchers

563 citations

Journal ArticleDOI
TL;DR: In this paper, an extensive literature review is conducted on emerging power quality challenges due to renewable energy integration, which are caused by non-controllable variability of renewable energy resources.
Abstract: Renewable energy becomes a key contributor to our modern society, but their integration to power grid poses significant technical challenges. Power quality is an important aspect of renewable energy integration. The major power quality concerns are: 1) Voltage and frequency fluctuations, which are caused by noncontrollable variability of renewable energy resources. The intermittent nature of renewable energy resources due to ever-changing weather conditions leads to voltage and frequency fluctuations at the interconnected power grid. 2) Harmonics, which are introduced by power electronic devices utilized in renewable energy generation. When penetration level of renewable energy is high, the influence of harmonics could be significant. In this paper, an extensive literature review is conducted on emerging power quality challenges due to renewable energy integration. This paper consists of two sections: 1) Power quality problem definition. Wind turbines and solar photovoltaic systems and their power quality issues are summarized. 2) Existing approaches to improve power quality. Various methods are reviewed, and the control-technology-based power quality improvement is the major focus of this paper. The future research directions for emerging power quality challenges for renewable energy integration are recommended.

518 citations

Journal ArticleDOI
TL;DR: An exhaustive study about different discrete-time implementations of resonant controllers, extending to the discretization of the schemes with delay compensation, which is proved to be of great importance in relation with their performance.
Abstract: Resonant controllers have gained significant importance in recent years in multiple applications. Because of their high selectivity, their performance is very dependent on the accuracy of the resonant frequency. An exhaustive study about different discrete-time implementations is contributed in this paper. Some methods, such as the popular ones based on two integrators, cause that the resonant peaks differ from expected. Such inaccuracies result in significant loss of performance, especially for tracking high-frequency signals, since infinite gain at the expected frequency is not achieved, and therefore, zero steady-state error is not assured. Other discretization techniques are demonstrated to be more reliable. The effect on zeros is also analyzed, establishing the influence of each method on the stability. Finally, the study is extended to the discretization of the schemes with delay compensation, which is also proved to be of great importance in relation with their performance. A single-phase active power filter laboratory prototype has been implemented and tested. Experimental results provide a real-time comparison among discretization strategies, which validate the theoretical analysis. The optimum discrete-time implementation alternatives are assessed and summarized.

487 citations

Journal ArticleDOI
TL;DR: In this article, an enhanced distributed generation (DG) unit virtual impedance control approach is proposed, which can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic frequencies.
Abstract: In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic frequencies. In contrast to conventional virtual impedance control methods, where only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedance at fundamental and harmonic frequencies is regulated using DG line current and point of common coupling (PCC) voltage feed-forward terms, respectively. With this modification, the impacts of mismatched physical feeder impedances are compensated. Thus, better reactive and harmonic power sharing can be realized. Additionally, this paper also demonstrates that PCC harmonic voltages can be mitigated by reducing the magnitude of DG unit equivalent harmonic impedance. Finally, in order to alleviate the computing load at DG unit local controller, this paper further exploits the band-pass capability of conventionally resonant controllers. With the implementation of proposed resonant controller, accurate power sharing and PCC harmonic voltage compensation are achieved without using any fundamental and harmonic components extractions. Experimental results from a scaled single-phase microgrid prototype are provided to validate the feasibility of the proposed virtual impedance control approach.

425 citations