Steady-state analysis of a 5-level bidirectional buck+boost dc-dc converter

This paper presents a nonisolated multilevel buck+boost dc-dc converter suitable for high voltage and high power application. It is composed by a Buck-type and a Boost-type converters, both multilevel and bidirectional. The main features of proposed converter are: reduced voltage stress across the semiconductors, allowing its use in high voltage; bidirectional power flow; frequency operation of the inductor is a multiple of the switching frequency, reducing the volume of magnetic component. This paper focuses on the five-level structure of the proposed converter, in which the theoretical analysis is carried out and discussed. In order to validate the theoretical analysis, a prototype with 10 kW output power capability, 1 kV to 750 V input-to-output voltage and 20 kHz of switching frequency was constructed and experimented. The results attest the advantages of the new dc-dc topology and it is reported herein.