Active Stator Variable Speed Drive: 120 kW DC-fed demonstrator

Current requirements in multi-megawatts electric marine propulsion systems and wind power generation, particularly in off-shore plants, ask for drives with increased power densities. The recently proposed Active Stator (AS) Variable Speed Drive is a clear answer to this demand. A power density increase of up to 2–3 times is anticipated compared to the current state-of-the-art equivalent drives. Such a major leap forward is primarily achieved through the use of a machine with trapezoidal distribution of the air-gap flux density and through the integration of the machine power electronics into the machine frame, as is suggested by the expression Active Stator. The AS topology is well suited to both AC and DC supply types. This is an important feature when the previously mentioned applications of the AS topology are considered, as both are seemingly open to both types of supply. This paper describes the AS topology and reports the main results obtained from a DC-fed 120 kW demonstrator purposely built to prove the AS topology.