1,721,020 research outputs found
A control algorithm of power converters in smart-grids for providing uninterruptible ancillary services
No full textThis paper deals with the use of grid-connected photovoltaic (PV) power plants for supplying the ancillary service of reactive power compensation to the distribution grid. A control strategy has been developed for controlling both real and reactive power exchanged with the distribution network. The paper suggests how the real and reactive power references should be selected in order to maximize the electrical energy generated by PV arrays and to exploit the apparent power of the inverter close to its rated value. The choice suggested for reference signals allows reactive power compensation service also when the solar irradiation is negligible. The control strategy is then applied to a sample grid-connected PV unit, which has been simulated in Simulink environment. Numerical simulations show that, using an adaptive Perturb & Observe algorithm, the maximum power point tracking is achieved in about 2 seconds, both at starting and when the irradiation changes. The inverter is also capable of giving without interruptions the reactive power support to the grid, reducing grid currents and voltage drops along the line respect to the classical configuration where no reactive compensation is present
PROBLEMATICHE CONNESSE AL RECUPERO DI ENERGIA ELETTRICA IN AZIONAMENTI ASINCRONI PER TRAZIONE
No full textApproaches to analytical analysis of active filter behaviour
No full textThe paper deals with sample structures of active filters. The aim is the evaluation of an analytical model for analysing the influence that filter parameters have on behaviour of the device. The results give also the opportunity to carry out useful guidelines for filter design. By means of well-known mathematical procedures the traditional mathematical model of active filter is arranged to be suitable of an analytical solution of the system of differential equations. Solutions are expressed as a function of the time and by means of inner parameters. Therefore it is possible a simple evaluation of the influence of the parameter values on output filter currents
Power flow control strategy for for electricvehicles with renewable energy sources
No full textThe paper analyses the benefits given by a compound storage system with batteries and supercapacitors on board of road electrical vehicles supplied by fuel cells. A control strategy for the management of the energy is developed for the maximization of the vehicle autonomy and for the increase of the electrochemical battery life. The controller is based on two finite state machines and it is implemented on the DC/DC converters that interface fuel cells and supercapacitors to the batteries. Experimental tests made on a sample electrical drive fully validate the effectiveness of the suggested control technique
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