Field and Field-Circuit Description of Electrical Machines

The field and coupled field-circuit models of electrical machines are presented. The field model consists of. (a) finite element (FE) equations for the magnetic field, (b) equations describing eddy-currents and (c) equations, which describe the currents in the machine's windings. Moreover the FE equations are coupled by the electromagnetic torque to the differential equations of motion. In the presented field-circuit model the flux linkages with the windings are expressed by two components. One component with inductances and the other described by edge or nodal values of the magnetic potential. The FE equations are derived by using the notation of circuit theory. The approach to consider the differential equation of motion in the simulation is discussed in the paper.