PROPERTIES OF THE CO-ENERGY FUNCTION FOR AC MACHINES WITH NON-LINEAR MAGNETIC CIRCUIT

To create equations of AC machines with non-linear magnetic circuit Lagrange´s formalism can be used. A starting point for this is the co-energy function. In the paper properties of the co-energy function of most important types of AC machines are discussed. Introducing equivalent magnetising currents as substitute variables, the co-energy function can be rather easily foreseen. Qualitative analysis of physical phenomena in a given type of machine is a base of it. An approximation of the co-energy function for non-linear magnetic circuit is also presented