Novel method of power control of a DC to DC resonant converter

A method is proposed for the control of power in a DC-to-DC converter using a series resonant circuit. The converter operates at a constant frequency above the resonant circuit frequency. The power circuit of the converter consists of an inverter-fed series resonant circuit as the main stage and a reactive compensator stage that is used to obtain a variable capacitor or inductor. For the control of power, the switches of the compensator are operated at a constant frequency and the phase shift is suitably adjusted in a closed-loop manner in order to obtain a variable capacitor or inductor. Four topologies for the realization of the DC-to-DC converter are proposed and analyzed using the state-plane method. Experimental results obtained on a laboratory prototype validate the theoretical analysis