INDUCTANCE : ITS IMPORTANCE AND FUNCTION IN THE DESIGN AND CONTROL OF ELECTRIC MACHINES
Inductance is a key idea in the design of electric machines, and indeed in almost all electric equipment. When we consider the connection between machines and power-electronic controllers, and also with power systems, it becomes even more important.
But in spite of a very simple definition, inductance in machines is a complicated subject. For one thing, it contains many components of self- and mutual inductance, all of which may vary with rotor position and current, making the overall inductance model variable and non-linear. Traditional design methods divide the machine inductance into fictitious components such as slot-leakage, differential, and synchronous inductances, none of which can be visualized directly in a typical finite-element flux-plot. Yet the finite-element method is an extraordinary tool for mastering the difficulties in inductance calculations, as long as we understand how to use it in a way that is consistent with correct machine design and analysis procedures.

Prof. Miller will try to review the whole subject of inductance in machines, starting from the basic definitions and describing the important components and the methods of calculating them. Using examples especially created in collaboration with Yves Thiolière for the Powersys European JMAG training courses, he will show some of the most powerful ways in which the finite-element method can enrich the work of the electric machine designer, and how it can help the discussion between the machine designer and the control engineer.