Extending the power transfer capability of a three-port DC-DC converter for hybrid energy storage systems

Abstract

Design considerations for a three-port bidirectional DC-DC converter to be used in hybrid energy storage systems (HESSs) with the aim to increase the power transfer capability are discussed in this study. For this, an analysis of the power flow that allows obtaining the current waveforms is presented. Then, a loss model, that includes losses in semiconductors and the magnetic core, is proposed based as a function of the voltage variations in the energy storage devices considering all possible cases of power transference. The analysis reveals that it is possible to size the converter auxiliary inductances to reduce the converter currents and losses and therefore increase the power transfer capability. The analysis and the proposal presented in this study are validated using a 5-kW experimental prototype. Results show that it is possible to increase the converter transfer capability up to 80%.