D02.6 - A Medium-Voltage Bidirectional Isolated DC Transformer Using 3.3 kV SiC Devices

Thursday, March 26, 2026

12:00 PM - 1:45 PM CT

Location: Hemisfair Ballroom

Technical Dialogue Presenter(s)

Junjie Li, MS (he/him/his)

School of Electrical Engineering，Chongqing University

Presentation

Co-Author(s)

HL

Hongyu Lin

School of Electrical Engineering，Chongqing University
PJ

Peng Jiang

School of Electrical Engineering，Chongqing University
HF

Hao Feng

Chongqing University
LR

Li Ran

School of Electrical Engineering，Chongqing University

This paper demonstrates a 3.3 kV SiC MOSFETs-based neutral-point-clamped type dual-active-bridge converter for medium-voltage (MV) bidirectional isolated DC transformers. This design overcomes critical challenges in MV devices insulation and thermal management through: (1) An optimized six-layer PCB stack-up structure, prioritizing inner-layer copper for high-current busbars to resolve the IPC-2152 thermal constraints; (2) Non-isolated gate drivers with fiber-optic PWM transmission, minimizing parasitic oscillations; (3) An epoxy resin-potted medium-frequency transformer with Litz wire windings to suppress skin effects. In a 900 V/3 kV back-to-back test with an LLC converter, the prototype achieves 98.7% efficiency at 26 kW cycling power, significantly reducing system volume versus low-voltage devices series connection.