Finite reluctance approach: A systematic method for the construction of magnetic network-based dynamic models of electrical machines

The finite reluctance approach is based on a simple synergy between a basic magnetic domain decomposition rule and the voltage balance at the terminals of any winding acting in the domain. The finite reluctance approach is thought as a tool for fast dynamic simulations of any kind of machine, but it is particularly adapt for irregular flux geometries as in fractional-slot surface-mounted permanent magnet machines with large slots and high slot flux leakages, for which only the finite element method has found good usage. This approach is based on the definition of a complementary mesh interlaced with the reluctance mesh, on the concept of material cell, and on unique rules to carry out both reluctances and magneto-motive forces. At this scope, definitions of mesh nodes, co-nodes, and auxiliary nodes are shown. The iron saturation can be easily taken in account, as well as motion effects. The circuit flux linkages are elected as state variables for integration, and they are directly linked to the loop fluxes in the magnetic network. The finite reluctance approach has been applied in this paper for dynamic modeling of an inverter-fed permanent-magnet linear synchronous motor.