an investigation of dual stator winding induction machines

CHAPTER 3
FULL MODEL SIMULATION OF DUAL STATOR
WINDING INDUCTION MACHINE
3.1 Introduction
The conceptual idea of dual stator winding machines can be traced to publications in
the early 1900's [1.6, 3.1, 3.2]. From the point of view of the stator winding, dual stator
winding machines have been categorized as “split-wound” and “self-cascaded” [1.1]. The
split-wound dual winding machine was introduced in the 1920s to increase the power
capability of large synchronous generators. Its inherent redundancy has also been
exploited to achieve better drive reliability. The split-wound synchronous machine and
squirrel-cage machine have different rotor structures and the same stator structure with
two similar but separate three-phase winding sets wound for the same number of poles.
Since the two windings have the same pole number, they are mutually coupled resulting
in significant circulating currents in the presence of unavoidable unbalances in the supply
voltages. The second kind of dual winding machine, the “self-cascaded machine”,
recently christened the brushless doubly-fed machine (BDFM) was introduced by Hunt in
1907. It requires a special rotor structure that has some nested loops on the rotor to
incorporate the effects of the cascade connection. [1.7, 1.8, 3.3]. The special rotor
structure increases the cost of the machine, its efficiency is relatively low, but has
potential utility in drive applications with a narrow speed range [1.7, 3.3].
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