This paper presents the analysis and design of a compact high-frequency planar transformer with medium-voltage (MV) isolation, suitable for a wide range of modular MVAC to DC architectures. The transformer uses high-voltage PCB windings fully enveloped by low-voltage windings in a modified 12-layer stack-up with embedded polyimide layers. Thermal management components provide high conductivity to an enclosure, and the entire assembly is potted with high-dielectric-strength epoxy. The transformer enclosure, including thermal management components, achieves a power density of 4.6 kW/l. It is used in a 10 kW, 800–960 V dual-active-bridge converter operating at 200 kHz with 98% measured efficiency. A hipot tested isolation of 26 kV is achieved between the primary and secondary windings of the proposed transformer assembly.
