22 research outputs found
Nonlinear control design and averaging analysis of a full-bridge boost rectifier
We are considering the problem of controlling AC/DC full bridge converters. The control objectives are twofold:(i) guaranteeing a regulated voltage for the supplied load, (ii) enforcing power factor correction (PFC) with respect to the main
supply network. The considered problem is dealt with using a nonlinear controller that involves two loops in cascade. The inner-loop
is designed, using sliding mode approach, to cope with the PFC issue. The outer-loop is designed to regulate the converter output
voltage. While several double-loop regulators (designed for different converters) can be found in the relevant literature, it is the first time that a so formal average analysis is developed that rigorously describes the controller performances. The development of such
theoretical analysis framework is a major motivation of this paper.Postprint (published version
Advanced nonlinear control of a grid-connected photovoltaic power system using N-cascaded H-bridge multilevel inverters
Nonlinear control of wind energy conversion system based on DFIG with a mechanical torque observer
Nonlinear control of multicellular single stage grid connected photovoltaic systems with shunt active power filtering capability
Nonlinear control of single-phase shunt active power filter. Theoretical analysis of closed-loop performances.
The problem of controlling single-phase shunt active power filter is addressed in presence of nonlinear loads. The control objective is twofold: (i) compensation of harmonic and reactive currents absorbed by the nonlinear load; (ii) regulation of the inverter output capacitor voltage. A two-loop cascade control strategy is developed that includes an inner-loop designed, using the backstepping technique, to cope with the compensation issue and an outer-loop designed to regulate the capacitor voltage. The controller performances are formally analysed, using the averaging theory. The analysis results are illustrated by simulation.Preprin
Fermentaci贸n controlada de aceitunas verdes picholine marroqu铆es sometidas a choque t茅rmico e inoculadas sin sal
The present work reports the controlled fermentation of heat-shocked, unsalted and inoculated green olives. The effects of heat-shock (60, 70 and 80 掳C three times for 5 min), inoculation with the oleuropeinolytic strain of L. plantarum FSO175 (L.p-FSO175) and the addition of Cell-Free Supernatant of C. pelliculosa L18 (CFS of C.p-L18) on the fermentation process of unsalted green olives were examined. The results showed a drastic reduction in the initial indigenous Enterobacteria, and an improvement in the acidification of heat-shocked olives at 70 and 80 掳C, when compared to 60 掳C. The inoculation with L.p-FSO175 and addition of CFS of C.p-L18 enhanced the fermentation and preservation of unsalted green olives, indicated by a significant decrease in pH, increase in free acidity and total disappearance of Enterobacteria. The heat-shock treatment at high temperature (80 掳C), inoculation with L.p-FSO175 and addition of CFS of C.p-L18 led to the best reduction in bitterness, and favorable color changes (L, a, and b) in fermented olives. This sequential method led to more appreciated sensory characteristics (mainly bitterness and color) of fermented olives, lower spoilage incidence in olives, and reduced fermentation time to 50 days, and therefore may be suitable to control the fermentation of unsalted green olives of the Moroccan picholine variety.El presente trabajo reporta la fermentaci贸n controlada de aceitunas verdes sometidas a choque t茅rmico, sin salar e inoculadas. Se estudian los efectos del choque t茅rmico (60 掳C, 70 掳C y 80 掳C tres veces durante 5 min), la inoculaci贸n con cepa oleuropeinol铆tica de L. plantarum FSO175 (L.p-FSO175) y la adici贸n de sobrenadante libre de c茅lulas de C. pelliculosa L18 (CFS de C.p-L18), sobre el proceso de fermentaci贸n de aceitunas verdes sin salar. Los resultados mostraron la dr谩stica reducci贸n de las enterobacterias aut贸ctonas iniciales, y la mejora de la acidificaci贸n de las aceitunas sometidas a choque t茅rmico de 70 掳C y 80 掳C, en comparaci贸n con 60 掳C. La inoculaci贸n con L.p-FSO175 y la adici贸n de CFS de C.p-L18 mejor贸 la fermentaci贸n y conservaci贸n de las aceitunas verdes sin salar, indicada por una disminuci贸n significativa del pH, aumento de la acidez libre y desaparici贸n total de enterobacterias. El choque t茅rmico a alta temperatura (80 掳C), la inoculaci贸n con L.p-FSO175 y la adici贸n de CFS de C.p-L18 condujeron a una mejor reducci贸n del amargor y cambios de color favorables (L, a y b) en aceitunas fermentadas. Este m茅todo secuencial, que permiti贸 apreciar las caracter铆sticas sensoriales (principalmente amargor y color) de las aceitunas fermentadas, y una menor incidencia de deterioro en las aceitunas, y redujo el tiempo de fermentaci贸n a 50 d铆as, puede ser adecuado para controlar la fermentaci贸n de aceitunas verdes sin salar de Marruecos, variedad picholine
Backstepping controller of five-level three-phase inverter
Multilevel converters are becoming increasingly used in many industrial applications due to the many advantages that they offer. The improvements in the output signal quality, lower Total Harmonic Distortion (THD) and many other properties make multilevel converters very attractive for connecting photovoltaic generators to medium voltage grid directly or to be used in a local power supply. In this paper, we focus on the implementation of a three-phase five-level diode clamped inverter and design of a performing nonlinear controller using the Backstepping approach. The control objective is to generate, at the system output, sinusoidal three-phase voltages with amplitude and frequency fixed by the reference signal independently of load variations. The performance study of the multilevel inverter and the designed controller are made by simulations in Matlab/Simulink environment