Two related types of parametric transformers

Abstract

The paper describes the two types of parametric transformers referred to as the "chain type" and "cross-winding type". They are related in the sense that they have identical magnetic circuits, but they differ in their windings arrangement. These transformers utilize the principle of parametric oscillations to develop an output voltage and transfer energy from the input circuit to the output circuit without direct mutual coupling. The two types belong to two different categories in which the MMF's of the input and output circuits act either at right angle to one another (orthogonal) or along the same line (co-linear) in the common regions. The operation of each type is described by two simultaneous nonlinear differential equations and the magnetization characteristics which relate the MMF's and fluxes in the input and output sides of the transformer. The experimental results on a small unit show that the cross-winding type is more efficient and has a higher output to weight ratio than the chain type.