I would like to know if it is possible to design a generator with a single phase stator and a three phase wound rotor. I am interested in designing one in the neighborhood of 5-10kw for a grid tied wind turbine. A simple contactor can tie the stator to the grid and a standard VFD could feed the rotor to give a wider speed range.
Is there an arrangement of poles where the phases match up? (6 stator poles per rotor pole?) or will the slip cover a multitude of sins?
A three phase stator with the third phase tied to the two phases of the single phase lines has been suggested as a phase converter would be wired. (anyone care to explain two opposed phases being called single phase to me?)
The real question is which scheme I better if both are possible?
To clarify, A standard VFD would limit the generators operational speed range by half, but if it only feeds the rotor, then it would be suitable for a "simple" grid tie arrangement. The bi directional VFD would be more expensive since it would require grid synchronization, where the standard vfd would not.
Also,I mentioned using 3phase stator above, but I was not clear about the connection of the third phase to the other two phases with capacitors.