Minimum Current Operation of Impedance Control Network Resonant Converters

This paper presents a systematic methodology to minimize the rms currents in the resonant tank of an impedance control network (ICN) resonant converter through optimal selection of the combination of its three phase-shift control variables. To achieve this goal, the ICN converter is modelled and analyzed in phasor domain for the very first time, and this approach is shown to offer simple geometric visualization of the two major aspects of the converter operation: (i) the rms currents in its resonant tank, and (ii) its soft-switching capability. The shapes of the soft-switching regions and the minimum-current operating point within these regions are also derived. Finally, an example universal-input, 3.7 kW ICN-based onboard charger is designed using the proposed methodology.