This paper presents an optimisation method for the converter rating for a Brushless Doubly-Fed Induction Generator (Brushless DFIG) wind turbine, considering grid's requirements on reactive power and low voltage ride-through (LVRT) compatibility. Steady-state and transient models of the machine have been utilised for the reactive power management and LVRT analyses. The effects of machine parameters on the inverter rating are discussed and a method of adjusting the leakage and magnetising parameters by appropriate design of stator slot magnetic wedges is proposed. The analyses have been preformed on a prototype D400 frame 250 kW Brushless DFIG.