Search results for "Verters"
showing 10 items of 163 documents
Analytical and experimental evaluation of a WECS based on a Doubly Fed Induction Generator fed by a matrix converter
2008
In this paper the control of a grid-connected Wind Energy Conversion System (WECS), based on a sensorless vector controlled Doubly-Fed Induction Generator (DFIG) fed by a matrix converter, is presented. The matrix converter is controlled using a space vector modulation algorithm. Stability issues related to the operation of the WECS connected to the grid using a matrix converter are also discussed in this work. The influence of a synchronous rotating filter in the dynamic of the proposed WECS is analysed. A Model Reference Adaptive System (MRAS) observer for sensorless control of the proposed WECS is used in this work. Using the speed estimated by the MRAS observer the electrical torque of …
Identification of a Hammerstein model for DC/DC converters operating in CCM
2005
This paper deals with a method for identification of a Hammerstein model of DC-DC converters operating in continuous conduction mode (CCM). This model has the duty cycle and the output voltage as input and output, respectively; it consists of a static nonlinearity and a linear and time-invariant model. The aim of the modeling the system by means of a Hammerstein model is due to its capability of describing the converter in a range of steady-state operating points instead of a desired well defined operating point as occurs for the small-signal models which are the more common mathematical description to approach the study of the converters themselves. The nonlinear characteristic of the Hamm…
Nonlinear Modeling of DC/DC Converters Using the Hammerstein's Approach
2007
This paper deals with the modelling of highly nonlinear switching power-electronics converters using black-box identification methods. The duty cycle and the output voltage are chosen, respectively, as the input and the output of the model. A nonlinear Hammerstein-type mathematical model, consisting of a static nonlinearity and a linear time-invariant model, is considered in order to cope with the well-known limitations of the more common small-signal models, i.e. the entity of the variations of the variables around a well-defined steady-state operating point and the incorrect reproduction of the steady-state behavior corresponding to input step variations from the above steady-state operat…
Automatic EMI filter design for power electronic converters oriented to high power density
2018
In this paper, a complete computer aided procedure based on the power density concept and aimed at the automatic design of EMI filters for power electronic converters is presented. It is rule-based, and it uses suitable databases built-up by considering information on passive components available from commercial datasheets. The power density constraint is taken into consideration by imposing the minimization of the filter volume and/or weight; nevertheless, the system in which the automatically designed filter is included satisfies the electromagnetic compatibility standards limits. Experimental validations of the proposed procedure are presented for two real case studies, for which the per…
Design of EMI Filters Using Multi-Objective Optimization
2018
A multi-objective design procedure for EMI filters in power converters is proposed. In a first step, the results obtained by an automatic design of EMI filters for power electronic converters oriented to satisfy the electromagnetic compatibility standards and the power density constraint which impose the minimization of the filter volume and/or weight, are evaluated. In a second step, the power losses and the cost related to the EMI filter configurations are estimated. By using the dominance concept, the EMI filter designs which are part of the Pareto front are selected among a discrete set of feasible configurations. Therefore, the configurations of the Pareto front take into consideration…
Overview and performance comparison of grid synchronization algorithms
2014
Distributed power generation units are experiencing an impressive growth. Consequently, the amount of energy injected by non-linear loads as power converters is expected to increase. Stability and quality of the overall grid are heavily affected by performances of grid-side converters. In this paper, an overview of grid-synchronization technique is proposed. The grid-side inverter is implemented in MATLAB/Simulink® environment including current control and grid-synchronization section. Both Synchronous Reference Frame (SRF) and Decoupled Double Synchronous Reference Frame (DDSRF) PLL algorithms are implemented. A performance comparison is carried out under ideal and unbalanced utility condi…
Comprehensive Analytical Investigation for PV Plants and Their Control System with Reduced Power Electronics Equipments
2012
This paper presents a comprehensive analysis of a power generation system from PV source and it control system with a reduced power equipments connected with a power AC grid. The absence of the boost chopper as an actuator for Maximum Power Point Tracking concurs to make the system more reliable, affordable and moreover cheaper respect to a traditional one in which the boost chopper is used. The mathematical analysis exposed in the paper shows as a three phase inverter has two degrees of freedom allowing the simultaneous MPPT control and the synchronization with the power grid. The analysis also shows the way to determine the duty cycle of the inverter to deliver active power, and eventuall…
Intraluminal Doppler-sonography: a new device for data analysis and its in vitro test
2002
Summary form only given. A special data acquisition unit has been developed which allows to process on-line not only the mean-phasic Doppler shift signal but also to analyze the spectral contents and the received A-mode signal. The probe consists of a 3f-catheter which is activated by a pulsed transmitter-receiver (Millar). The carrier frequency is 20 MHz and the impulse repetition rate is 62.5 kHz. Two modular A/D converters are used. One digitizes directly the Doppler shift frequencies in the range less than 20 kHz (sampling rate 100 kHz, resolution 12 bit); the other digitizes the RF-signal (sampling rate 200 MHz, resolution 8 bit). For further processing, data are transferred via separa…
On the design of a multiple-output DC/DC converter for the PHI experiment on-board of solar orbiter
2013
Power converters for experiments that have to fly on board space missions (satellite, launchers, etc.) have very stringent requirements due to its use in a very harsh environment. The selection of a suitable topology is therefore not only based on standard requirements but additional more strict ones have also to be fulfilled. This work shows the design procedure followed to build the Power Converter Module (PCM) for the Polarimetric and Helioseismic Imager (SO/PHI), experiment on board the Solar Orbiter Satellite. The selected topology has been a Push-Pull, for a power level of approximately 35 W and with seven output voltages. Galvanic isolation is needed from primary to secondary, but no…