References of "Kobou Ngani, Patrick 50002112"
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See detailActive Harmonics Compensation in Smart Grids
Kobou Ngani, Patrick UL

Doctoral thesis (2018)

The quality of electric power is a key factor for the electricity supply service. It defines how good the characteristics of the supplied power meet the standard ones. Among several other power quality ... [more ▼]

The quality of electric power is a key factor for the electricity supply service. It defines how good the characteristics of the supplied power meet the standard ones. Among several other power quality issues, the harmonics are of more and more concern over the last decades. This is essentially due to the widespread use of electronic components. This thesis focuses on the development of a voltage active power filter implementing a new selective harmonics compensation algorithm. The first design is described as following: band-pass filters decompose the measured voltage signal as a sum of different harmonics voltages; PLLs (frequency-tuned) transform of the oscillating signals into two orthogonal and rotating components (dq-transform). The dq-components of each harmonic are controlled to zero using standard PI-controllers and the compensating harmonics waves are generated via the inverse PLL. All the harmonics compensating waves are superimposed and added to the fundamental reference signal. This represents the final control signal of the inverter. Implemented in the MATLAB-SIMULINK simulation environment, this foreseen methodology depicted as major issue the control stability especially when the system frequency differs from the rated 50-Hertz frequency. This is the reason why a second design has been proposed. The major improvement is done on the harmonics detection stability by replacing the PLLs frames by the well-known internal frame of the fundamental voltage of the controlled inverter. After the convincing theoretical results from the simulations, the method is implemented and validated experimentally on a test rig in the lab. The two key features of the developed active power filter (APF) are: 1)Its ability to be used as a standalone power unit that compensates by itself the harmonics that could appear in the system while generating the fundamental voltage necessary to build up the micro-grid. 2)Its ability to serve as a full grid-tied power element that not only mitigates the voltages harmonics on the coupled grid but also supports the grid by controlling the exchanged active and reactive powers between the inverter and the grid. In addition to the developed harmonic mitigation technique, a new grid synchronization method has been proposed along with a new power control algorithm combined with a grid impedance estimator for grid-tied inverter. Further investigations and development are required for three-phase unbalance voltage systems as well as for single-phase voltage power system for low power grids. [less ▲]

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See detailA New Synchronization Method for Three - phase Grid - tied LC-Filtered Voltage Source Inverters
Kobou Ngani, Patrick UL; Hadji-Minaglou, Jean-Régis UL; De Jaeger, Emmanuel et al

in International Journal of Emerging Engineering Research and Technology (2017), 5(5), 7-15

In order to identify and to track the phase angle and magnitude of the grid voltage, several synchronization methods exist, among which the phase-locked loop (PLL) algorithm is the most popular. This ... [more ▼]

In order to identify and to track the phase angle and magnitude of the grid voltage, several synchronization methods exist, among which the phase-locked loop (PLL) algorithm is the most popular. This paper presents a new synchronization method for grid-tied voltage source inverters (VSIs) based on the intrinsic inverter synchronous reference frame. The absolute phase angle of the grid voltage is not required but its voltage direct and quadrature components into the well-known inverter frame. The advantages of this method is its low computational load with a reduced number of control parameters, as well as its robustness and effectiveness. This property makes it very convenient for embedded control systems with limited computing resources. Simulations and experimental test results are presented to prove the performance of the proposed method. [less ▲]

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See detailA new Single-phase PLL based on the input voltage magnitude estimation
Kobou Ngani, Patrick UL; Hadji-Minaglou, Jean-Régis UL; Marso, Michel UL et al

Scientific Conference (2015, December 17)

Many automatic control applications such as wide scale power grid management and local power conditioning rely on the fast and accurate detection of the voltage signal phase and amplitude. These ... [more ▼]

Many automatic control applications such as wide scale power grid management and local power conditioning rely on the fast and accurate detection of the voltage signal phase and amplitude. These information are almost all the time given by the Phase –locked Loop (PLL) systems and can be single-phase or three-phase and have many different structures. Many single-phase PLLs core structure are based on the regulation to zero of the voltage direct component in the rotating d-q frame obtained through the Park-transform. Their accuracy and dynamic rely on how quick and accurate the second voltage’s component in the static α-β frame is estimated. This paper presents a new single-phase PLL structure, also based on the same core structure as described before, but implementing a novel voltage β-component generation. A brief review of some single-phase PLLs is made, then the proposed novel PLL structure is detailed and its performance is compared with that of the other PLL’s taking into consideration the following signal disturbances: amplitude variations, phase step variation and frequency fluctuations as well as harmonic distortion. [less ▲]

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See detailPhase-error correction by single-phase phase-locked loops based on transfer delay
Kobou Ngani, Patrick UL; Hadji-Minaglou, Jean-Régis UL; Marso, Michel UL et al

in Journal of Electrical & Electronic Systems (2015, November 04)

Comparative studies of different single-phase phase-locked loops (PLL) algorithms have been made. They show that the PLL based on sample delay (dPLL), presents the lowest computational load and is as ... [more ▼]

Comparative studies of different single-phase phase-locked loops (PLL) algorithms have been made. They show that the PLL based on sample delay (dPLL), presents the lowest computational load and is as robust as the three-phase synchronous reference frame PLL dqPLL by input signal amplitude and phase variations. Its weakness appears when the input signal frequency differs from its rated frequency: It depicts a steady error on the calculated signal phase-angle. After a brief review of the dqPLL which constitutes debase structure of the dPLL, the following work will present three methods that improve the phase detection accuracy of dPLL. It is shown that the modifications brought in the original structure do not influence the robustness and stability of the algorithm but reduce the phase angle offset error by input signal frequency variation. This is corroborated by tests including not only the fundamental input voltage disturbance like amplitude, phase and frequency variation but also harmonic voltage distortion. [less ▲]

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See detailDistributed Harmonic Compensation for Power Quality in Smart Grids
Kobou Ngani, Patrick UL; Hadji-Minaglou, Jean-Régis UL; Marso, Michel UL et al

in Cahier Scientifique - Revue Technique Luxembourgeoise (2014)

It is now well known that the quality of electric power is a key factor for the electricity service. It defines how good the characteristics (amplitude and frequency) of the supplied power meet the rated ... [more ▼]

It is now well known that the quality of electric power is a key factor for the electricity service. It defines how good the characteristics (amplitude and frequency) of the supplied power meet the rated ones. Voltage dip (or sag) and swell, short and long interruptions, voltage spike, under and over voltage, harmonic distortion, voltage unbalance are the common power quality problems. Among these last, the harmonics issue is getting more and more important over the last decades and this trend will surely continue its race. This is essentially due to the widespread use of electronic components in electric equipment: it changes the nature of the electric loads from linear to non-linear and makes them, on the one hand, responsible for the harmonics generation in the power grid but very sensitive to the power quality problems on the other hand. [less ▲]

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See detailMicro-cogénération à partir de biogaz: Modélisation et Rentabilité pour une PME Agro-alimentaire
Kobou Ngani, Patrick UL

in Revue Technique Luxembourgeoise (2014), HORS SERIE(#10), 17-19

L’optimisation énergétique des procédés de transformation constitue une des réponses les plus efficaces et adoptées face aux nouvelles contraintes européennes dans le secteur de l’énergie et de ... [more ▼]

L’optimisation énergétique des procédés de transformation constitue une des réponses les plus efficaces et adoptées face aux nouvelles contraintes européennes dans le secteur de l’énergie et de l’environnement. Ce travail présente comment la brasserie artisanale de Rulles (PME agro-alimentaire) peut, par une installation de biométhanisation couplée à une unité de micro-cogénération, faire de la dépollution de ses rejets d’eaux usées une production énergétique. Le bioréacteur aura comme matière première les eaux usées de la brasserie et produira du biogaz et des eaux quasiment non nocives pour l’environnement. Le biogaz produit servira de carburant pour l’unité de cogénération dont l’énergie produite sera réutilisée. Des unités de stockage tant pour la chaleur que pour le biogaz sont des éléments clés envisagés pour assurer un meilleur fonctionnement du système . Une telle installation remplira donc une double fonction : l’épuration des eaux usées d’une part et la production d’énergie d’autre part. [less ▲]

Detailed reference viewed: 178 (11 UL)