High Efficiency Wind Generators with Variable Speed Dual-Excited Synchronous Machines

Wind power seem to be one of the most interesting technology for electrical energy generation by renewable sources. It is necessary to set up carefully the wind turbine taking into account that the wind speed is variable with the time and there is a fluctuation of power output of wind energy conversion systems. There are many technical solutions adopted to increase the system efficiency by utilizing proper generators. In the paper the case of variable speed dual-excited synchronous machine is investigated. For its control possibilities, this machine is particularly suitable for variable-speed constant frequency applications like wind power generation systems. In the paper, after presenting the mathematical model of the wind turbine and the generator, a control technique for output power maximization is proposed. Results obtained by numerical simulations are discussed in the paper to demonstrate that using the proposed control algorithm it is possible to achieve a significant increment on the power generated in comparison with that obtained using an unregulated induction machine.