Design issues of the high-frequency interleaved DC/DC boost converter with Silicon Carbide MOSFETs

Abstract

This paper discusses design issues of the high-frequency, four-leg interleaved DC/DC boost converter (6kW/650V ) that combines high efficiency with high power density. Low switching energies of the applied SiC MOSFETs and Schottky diodes offer operation at high switching frequency. Together with suitable phase-shift of the control signals this leads to input/output current frequency multiplication up to 0.5MHz. Such a high frequencies and cancellation of the current ripples result in a significant reduction of the passive components, especially input inductors. The paper contains discussion of the converter operation and special solution the MOSFET gate drivers with CPLD logic. A design study regarding SiC semiconductors, inductors and cooling system, is also provided. Discussed issues are illustrated by simulation and experimental results. The 4×125kHz DC/DC boost converter (volume 0,75dm3) reaches efficiency close to 99% at nominal power of 6kW.