Academic Partners

Chandra Pun

PhD Title - Reduction in direct drive generator cost through active control of the airgap

Start Date - October 2014

Degree - MSc in Wind Energy System, University of Strathclyde; BEng in Electrical Engineering, Institude of Engineering, Pulchowk Campus.

Research Bio

A possible use of the modular power electronic converters connected to multi-coil generator that can regulate the airgap closing force has been demonstrated in the literatures. This project is to present the possible solution to the problem related to closing of airgap in the large scale direct drive generator by developing suitable control strategy for modular power electronic convertors that can be connected to the groups of coils in multi-coil permanent generator to achieve airgap regulation. Maintaining uniform airgap in a large scale permanent magnet direct drive generator with minimum weight and cost is a challenge. Failure to achieve it can cause the physical contact of rotor and stator, which in turn lead to structural damage of the generator. The scope of directly controlling the field excitation to control the attraction force as necessary like in conventional field excited synchronous machine cannot be achieved in Permanent magnet machine due to permanent presence of the field. This requires the rotor and stator to have additional structural stiffness enough to resist the possible deformation due to attraction forces. However, the weight of generator can be issue in this case and can be even challenging as its size scales up.