1,721,157 research outputs found
Light-to-Light: PV-fed LED Lighting Systems Matching PV and LED Power
No full textThis paper discusses the principle of operation, dynamic
modeling, and control design for light-to-light (LtL) systems,
whose aim is to directly convert the sun irradiation into artificial
light. The system discussed in this paper is composed by a photovoltaic
(PV) panel, an LED array, a dc–dc converter dedicated to
the maximum power point tracking of the PV panel and a dc–dc
converter dedicated to drive the LEDs array. A system controller
is also included, whose goal is to ensure the matching between the
maximum available PV power and the LED power by means of a
low-frequency LEDs dimming. An experimental design example is
discussed to illustrate the functionalities of the LtL system
NEW APPROACHES TO THE TRUE-WORST-CASE EVALUATION IN CIRCUIT TOLERANCE & SENSITIVITY ANALYSIS: PART II - CALCULATION OF THE OUTER SOLUTION USING AFFINE ARITHMETIC
No full textProprietà elettriche di compositi conduttivi
No full textL’attività di ricerca riguarda la modellazione delle proprietà elettriche dei materiali dispersivi, con lo scopo di predire l’efficienza di schermatura alle onde elettromagnetiche di schermi realizzati con tali materiali. L’attività è stata condotta in parziale collaborazione con ricercatori stranieri del mondo industriale.
L’approccio di modellazione sviluppato può essere applicato a materiali compositi contenenti fibre conduttive. L’interesse per tali materiali compositi è motivato dal fatto che l’aggiunta di fibre, comportando una diminuzione della resistività elettrica, apre numerose opportunità applicative.
Per utilizzare questi compositi per la schermatura elettromagnetica occorre conoscere e stimare le proprietà elettriche modificate, ovvero la permittività complessa effettiva del materiale composito, in funzione della concentrazione dell’additivo conduttivo. Di rilevante interesse sono i materiali da costruzione, quali il calcestruzzo, la cui bassa conducibilità elettrica ed efficienza di schermatura possono essere aumentate sensibilmente mediante additivi conduttivi, ottenendo così una soluzione pratica di costo limitato impiegabile quando non siano richieste elevate prestazioni schermanti
Understanding commutations in switching converters. II. Analysis and synthesis of DC-DC regulators
No full textSteady-state analysis of hard and soft switching DC-to-DC regulators
No full textIn this paper, a unified method for steady-state analysis of hard-switching and soft-switching DC-to-DC converters is presented. The power stage and the feedback control circuit forming the regulator are modeled separately and analyzed as two interconnected blocks. The intersection of the open loop DC steady-state characteristics of these cascaded blocks provides the initial condition for a guess candidate steady-state solution (CS). The CS is validated as true steady-state solution (TS) if the bias conditions of switching devices are fulfilled everywhere in the switching period, otherwise the CS is changed according to the conditions violated. The CS approaches the TS through an iterative process of validation. The basic tools adopted to ensure a reliable computation of the CS are interval analysis (IA), for the identification of the commutation instants (CI), and the compensation theorem (CT), for the analysis of commutations. Some examples of applications to hard-switching and soft-switching DC-DC regulators are presented
Frequency domain analysis of DC-DC converters with internally controlled switching instants
No full textCONTROLLER APPARATUS WITH MAXIMUM POWER POINT TRACKING FOR CONTROLLING AN ELECTRIC POWER GENERATION SYSTEM BASED ON PHOTOVOLTAIC SOURCES, CONTROLLING METHOD AND RELATED ELECTRIC POWER GENERATION SYSTEM
No full textSteady state analysis of pwm dc-to-dc regulators
No full textA new method for steady-state analysis of pulsewidth modulation (PWM) hard-switching dc-to-dc regulators is presented. The power stage and the feedback control circuit are analyzed as two interconnected blocks. The intersection of their open-loop dc steady-state characteristics with the ramp voltage provides a guess candidate steady-state solution (CS). An iterative process is used to validate it as true steady-state solution (TS) when the bias conditions of switching devices (SDs) are fulfilled everywhere in the switching period
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