Resonant Immittance Converter Topologies

An immittance converter (IC), in general, is a two-port network, in which input impedance is proportional to the load admittance connected across the output terminals and is useful in transforming a voltage source into a current source and vice versa. In this paper, a family of lumped-element resonant IC (RIC) topologies is identified by investigating the transmission parameters of various topological structures of electrical networks. In all, 24 RIC topologies have been identified with three and four reactive elements. The operating point and the design condition, under which these topologies exhibit immittance conversion characteristics, are derived. The suitability of these topologies in terms of absorbing parasitic components and providing inherent dc blocking to the transformer is examined. The analysis and design is illustrated with a newly identified four-element RIC topology as a constant-current power supply and validated with experimental results on a 250-W 105-kHz prototype converter.