Research on excitation control for stand-alone wound rotor brushless doubly-fed generator system

Brushless doubly-fed generator (BDFG) as a stand-alone power generation has a wide application of variable speed constant frequency (VSCF) generator in some embedded generation systems, such as ship shaft generator systems. In this paper, an excitation control strategy for stand-alone BDFG is introduced, the similarities and differences of system structure and control strategy between the grid-connected and stand-alone BDFG are also analyzed and compared. Under stand-alone situation, the quality of stator power winding output voltage is strongly affected due to active and reactive power component of load, to tackle this problem, the steady equivalent-circuit and power flow of the BDFG is comprehensively developed and analyzed. The experiments included in this paper were carried out on a 4/8-pole 64kW wound rotor BDFG.