Wind turbine power converters: a comparative study

Two of the most promising types of power converter applicable to the task of interfacing variable-voltage DC energy sources to the grid are compared. The converters studied are first a DC/DC power converter with a current-controlled voltage source inverter and, secondly, the line-commutated SCR with an active compensator for reduction of harmonic current and reactive power demand. The comparison is drawn with particular reference to use with variable-speed permanent-magnet wind turbine generators. The optimal power transfer, reactive power/voltage regulation and harmonic minimisation are addressed. Experimental results from laboratory models are presented alongside simulation results, which are in good agreement, to demonstrate the power control and harmonic performance of these systems. Power losses and semiconductor costs are also discussed.