Power balance and efficiency maximization of multi-parallel boost converter module for hydrogen-fuel-cell hybrid railway system

Abstract

Recently, in order to improve power supply flexibility of the railway propulsion system, hydrogen fuel cells have been introduced. Although hydrogen fuel cells show high energy efficiency, their production cost can be a significant issue when considering high DC voltage of inverters for driving traction motors. To improve the cost impact of hydrogen fuel cells, boost converters should be required between low DC voltage hydrogen fuel cells and high DC voltage inverters. To transfer a high power rating of over 200kW from a hydrogen fuel cell to a traction inverter, a boost converter can be implemented in multiple modules, connected in parallel. Moreover, for efficient use of hydrogen fuel cell, boost converter should have high efficiency for the entire load range. In this paper, based on optimal design of the respective boost converter module, a power balance control scheme will be investigated for railway propulsion systems with hydrogen fuel cells. Furthermore, total power efficiency of boost converter will be maximized by controlling the number of operating boost converter modules according to loading condition. Finally, both a control scheme for power balance and efficiency maximization will be verified by PSIM simulation results. ? 2019 The Korean Society for Railway. All rights reserved.