Active stator, a new generator topology for direct drive permanent magnet generators

Active Stator is a brushless DC machine technology, differing from brush commutated DC machines by having a field that rotates about a stationary armature, and a stationary electronic commutator that employs power electronics for active control. The switching sequence of the electronic commutator provides phase rotation. Active Stator is particularly well suited to the requirements of direct drive wind turbine driven generators operating at low speed with quadratic steady state torque speed characteristics. An Active Stator generator outputs medium voltage DC, and can be connected to an AC grid via a DC-AC converter, or a DC grid, thereby supporting the installation of an economical DC grid for interconnecting offshore wind turbine farms, and eventual transmission to shore.