Taking into account the nonlinearity of the shaft and the interaction of me
chanics and electric in the generator sets, we got a transient model by com
bining the Park equations With mechanical equations. The self-excited reson
ance of the system caused by too-large line resistance or stator resistance
is investigated using nonlinear normal modes and invariant manifold method
. Theoretical results show that a supercritical Hopf bifurcation occurs whe
n the resistance becomes larger. The experimental results show high similar
ity with the theoretical conclusions.