Compare different generator types used in wind turbines.

Wind turbine generators include: Squirrel-cage induction generator (SCIG) - simple, robust, fixed speed, needs soft-starter and reactive compensation. Doubly-fed induction generator (DFIG) - variable speed via partially-rated converter on rotor, dominates market, limited speed range. Permanent magnet synchronous generator (PMSG) - full-rated converter, no gearbox possible (direct drive), higher efficiency, uses rare-earth magnets. Electrically-excited synchronous generator (EESG) - avoids magnets but needs slip rings. Selection trades off efficiency, cost, reliability, and grid compatibility.