Rq. Li et al., DETERMINATION OF CONVERTER CONTROL ALGORITHMS FOR BRUSHLESS DOUBLY-FED INDUCTION-MOTOR DRIVES USING FLOQUET AND LYAPUNOV TECHNIQUES, IEEE transactions on power electronics, 10(1), 1995, pp. 78-85
This paper presents a method of analyzing the stability of brushless d
oubly-fed machines (BDFM) in the synchronous mode of operation. Unlike
the stability analysis of conventional induction and synchronous mach
ines for which the linearized state equations are time-invariant, the
linearized state equations of the BDFM are time-varying and, consequen
tly, their eigenvalue analysis cannot be performed directly. However,
since the system matrix of the linearized equations is a periodic func
tion of time, the generalized theory of Floquet can be applied to tran
sform the time-varying system of equations into an equivalent set of e
quations with a constant system matrix. Eigenvalue analysis can then b
e employed to analyze the stability characteristics of given equilibri
um points. Investigation into the stability of a proof-of-concept BDFM
in the synchronous mode of operation using the transformed linearized
model shows good correlation between theoretical and experimental res
ults. In addition, the possibility of designing a BDFM drive with inhe
rent open-loop stability over the entire speed range is demonstrated.
Finally, under stable steady state synchronous operation, converter co
ntrol methods are discussed and it is shown that scalar control method
ologies similar to those for induction motor drives can be applied to
the BDFM.