The Dynamics of Coupled Circuits with Ferromagnetic Non-Linearity

Interest in the circuit approach to the analysis of electric power apparatus has been increasing rapidly over the past decade. In academic circles it has almost supplanted the field based approach, the classical texts being mainly out of print and replaced by a wide variety of texts with phrases such as "dynamic circuit theory" or "generalized machine theory" in their titles. This wholehearted acceptance which came about for a variety of reasons has however not been reflected in industrial circles. Here, despite considerable interest fostered bv the success of the circuit approach in some areas of current interest, such as the stability of inverter fed machines, a more cautious attitude prevails. This is natural since the paramount industrial need is to provide numerical solutions to practical problems involving apparatus which natentlv does not fit the standard simplifying assumptions of the circuit approach. To generate confidence in the solutions it is necessary to investigate the appli cabilitv of these assumptions and to establish analyrtic nrocedures appronriate to the problems encountered.