Linear Control Compensator for a Variable-Transformer in Wide-Voltage Power Converters

Abstract

This work presents the design and simulation of a controllable magnetic device. The device can help the Dual Active Bridge converter (DAB) to operate in the soft switching region for wide-load applications. The control law is based on the modification of the ferrite-core's permeance for Variable-Transformers (VT). The frecuency-domain's model of the VT control leg is obtained using the Gyrator-Capacitor theory. Finally, this model is found by the premise that the interactions of the transformer's main fluxes are minimum in the control leg, furthermore this paper also proposed a ferrite-core construction that reduces these interactions, therefore the induced voltage in the control winding is also minimized, meaning the parallel interactions of the fluxes are reduced. The results shows that the perturbations are manageable for the control scheme and do not affect the device operation.

Magnetically Controlled Transformer With Variable Turns Ratio and Low Series Inductance: Analysis and Implementation Toward Its Application in SMPS

“…This pre-magnetization can be accomplished by the addition of an auxiliary winding in the core, connected to a constant current source. According to the orientation of the generated DC magnetic flux relative to the main magnetic flux, the biasing method can be classified as: parallel, orthogonal, or radial, see [34,Fig. 3].…”