Performance comparison among different converters fed by self excited wind driven induction generators

A valid solution to the problem of feeding remote loads, that cannot be linked to the mains for economic reasons, is given by the use of wind energy. These plants, using self-excited induction generators, connected to a battery by an AC-DC power converter, present several advantages, such as robustness, small need of maintenance, low cost of the machine and intrinsic safety, thanks to the self-excitation phenomenon. The aim of the present paper is the comparative analysis of two different power conversion topologies: in one case a full-controlled thyristor bridge is employed; in the other, a diode bridge feeding a chopper is used. Having discussed the wind speeds selection criteria, some equivalent models for steady-state sinusoidal operation are developed, of basic importance for the design. The operating characteristics obtained by numerical analysis are then shown and discussed