Lightweight, ironless-stator, PM generators for direct-drive wind turbines

A new form of direct-drive PM generator for wind turbines is described. Despite being a very low speed machine, it is very light in weight because of its large diameter and the absence of iron in the stator magnetic circuit. Its efficiency is good and it offers the possibility of fault-tolerant operation and high-voltage output, eliminating the need for a unit transformer. A 2m diameter laboratory demonstrator is shown and initial measurements confirm design data.