Capacitive Based Isolated Resonant Switched Capacitor Solid State DC Transformer

The ability to provide galvanic isolation is a key requirement in power electronics applications such as data center power delivery network, telecom power system, Electrical Vehicles on board chargers or floating auxiliary supplies. Typically, isolation is provided by means of magnetic transformers, which share a noteworthy portion of the total volume and losses of the system. This work presents a novel, capacitive based isolated, fixed gain resonant switched capacitor (ReSC) DC/DC converter as a higher power density, lower volume, lower weight alternative to the transformer based isolated converters. Capacitors are used as the isolation coupling element as well as the differential mode power processing elements. The presented converter modulation makes it suitable for use in interleaved multi-cell architectures without the generation of additional circulating current between cells. A 100V, 200W proof of concept prototype is built to validate the topology. Higher than 97.5% efficiency in the whole operating range is reached and low frequency common mode isolation is demonstrated.