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

This paper presents the design and simulation of a controllable magnetic device, which can help the Dual Active Bridge converter (DAB) to reduce the losses in the soft switching region for wide-load applications. The control law is based on modifying the permeance of ferrite-cores for Variable-Transformers (VT). The frequency-domain 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, thereby minimizing the induced voltage in the control winding, implying the parallel interactions of the fluxes are reduced. The results indicate that the perturbations are manageable for the control scheme and do not affect the device operation.