Investigation into Magnetic Control of Hard-Switching DC-DC Converters

In this paper an investigation into magnetic control (MC) of hard-switching (HS) DC-DC converters is carried out. The proposed control method is based on the modulation of the effective filter inductance of the converter when operating in discontinuous conduction mode (DCM). It is well known that the output characteristic of a HS DC-DC converter operating in DCM is dependent on the effective inductance of the output filter. This way, by using a variable inductance the output of the converter can be controlled. The proposed control method can be applied to any converter topology, namely buck, boost, buck-boost, flyback, forward, and so on. In this paper, the operation of the buck converter with MC is investigated in detail as a case study. This work proves that the proposed control method can be effectively used to control DC-DC converters on its own or by combination with other control parameters as duty cycle and/or frequency. An experimental prototype has been built to test the proposed control method and modeling process and to demonstrate its feasibility and possibilities.