The information provided in this paper is derived entirely from a PhD dissertation written by Paul C. Roberts and submitted to Emmanuel College, University of Cambridge on September 2005.  My paper can be found here.

Simulation of an Induction Motor in the Rotating and Synchronous D/Q Planes

This paper is provided only to verify the analysis and findings presented by Paul C. Roberts.

In his paper Paul C. Roberts provides a detailed theory of operation and practical implementation for a Doubly-Fed Induction (dual stator) machine. A copy of  the paper written by Paul C. Roberts can be found here.

A Study of Brushless Doubly-Fed Induction Machines

It is highly suggested that the reader review in detail the theory provided by Paul C. Roberts first before referring to the information provided in my paper. My paper for the most part provides only a practical validation to that presented by Roberts based on a traditional 3-phase, single stator induction machine.