Converter rating optimisation for a brushless doubly fed induction generator

This article studies the converter rating requirement of a Brushless doubly-fed induction generator (DFIG) for wind turbine applications. Practical constraints such as the generator torque-speed requirement, reactive power management and grid low-voltage ride-through (LVRT) are considered. Experimental data have been used to obtain a realistic system model of a Brushless DFIG in a wind turbine. The study shows that there is a minimum converter rating, dependant on operating point, but this may not be achievable without machine derating. The use of a capacitor bank enables the converter ratings to be reduced without compromising the machine's performance. The effect of the machine's leakage inductance on the interplay of LVRT, achievable system power factor, converter rating and losses is investigated.