Design of Oil Insulated SiC Diode Rectifier for an MVDC SST

A DC solid-state transformer is needed to interconnect PV sources to a medium voltage DC network. Due to the application requirements, unidirectional high step-up conversion is proposed. Immersion of the complete medium-voltage-side of the converter in transformer oil is proposed to achieve compact design. In this paper, we present the integration of the medium voltage and medium frequency diode rectifier in terms of cooling, dielectric design, and chemical compatibility, relying on printed circuit board technology.