10MW, 10rpm, 10Hz directly-driven cage rotor induction generator (CRIG): preliminary design with key FEM validations

With two 8MW wind generators in the commercial stage - both synchronous types: one with permanent magnets at about 480rpm (with transmission) and one directly driven d.c. excited (at 9rpm) and 10MW designs for directly driven at 10 rpm doubly fed induction generators (at 1.5-2 mm air gap for air gap diameters of 12m, grace to flexible framing allowable by the small speed / centrifugal force), the present paper tries to investigate if at 10MW, 10 rpm 10Hz; the cage rotor induction generator (CRIG) is feasible. Preliminary design and key FEM validations, which constitute the core of the paper yield a CRIG characterized by an efficiency of 0.92, power factor 0.86, active materials (core and copper-stator and rotor) weight of 82 tons, in an outer rotor topology with air gap diameter of 12m and an air gap of 2mm (a flexible frame is required).