Self-Balanced Input-Series Two-Stage DC-DC Converter and Ripple Match Design

This paper proposes a new self-balanced input-series, two-stage scheme suitable for high input voltage DC-DC converters. Series connection is applied for the first stage to reduce voltage stress, while a single second stage is used to regulate the charge balance of the first stage. Also, this research proposes a new ripple match concept to choose optimized first stage inductance value to reduce the voltage ripple across the intermediate capacitors, and thus, significantly suppress the current ripple of the second stage. A prototype with 500-700V input and 5V/30A output is built. Experimental results verify the principle and performance of the new topology.