Abstract
Fuel cell (FC)-driven railroad propulsion systems (RPSs) have been much appreciated for the past two decades to get rid exhausts of fossil fuels, but the inability of FCs to capture regenerative power produced by propulsion systems during regenerative braking and the dependency of its power density on operating current density necessitates the hybridization of FCs with batteries and/or supercapacitors to utilize the best features of all three power sources. Contrary to the research trend in hybridization where the purpose of hybridization such as fuel saving, high efficiency, or high mileage is achieved by certain operational algorithms without going into detail models, this study using detailed models explores the impact of high-power charging limitations of batteries on the optimization of hybridization, and proposes a solution accordingly. In this study, all three power sources were modeled, the optimal and suboptimal behaviors at the individual level were identified, and power distribution was implemented for a propulsion system, as recommended by the optimal features of all individual power sources. Since the detailed modeling of these power sources involves many mathematical equations and requires the implementation of continuous and discrete states, this study also demonstrates how, using C-MEX S-Functions, these models can be implemented with a reduced computational burden.
Highlights
Fuel cell (FC)-driven railroad propulsion systems (RPSs) have emerged as proenvironmental conveyance systems because of the emission-free operation of FCs as power sources
Typical internal combustion engines (ICE) are 28%–30% efficient while electric motors achieve an efficiency of 85%–95%
Hybrid vehicles retain the diesel-based engines as the master engine and used batteries to let the ICE engines operate at the optimum range by compensating the extra loads that might cause ICE to deviate from an efficient operating range [2]
Summary
Fuel cell (FC)-driven railroad propulsion systems (RPSs) have emerged as proenvironmental conveyance systems because of the emission-free operation of FCs as power sources. Transmission losses in ICE-based drives are higher as compared to losses in electrical transmission of power [1]. The development of batteries with the capability of propulsion increased the degree of electrification in the hybrid mix, it could not replace the ICE forever. The development of fuel-cells (FCs) made it possible to replace the ICE because the FC can give both high mileage and high power [3]. Most developed countries have already moved from combustion engines to FCs for powering locomotives [4]. FCs and batteries (Batt) as a primary source of power for propulsion have already become commercialized. Ultracapacitors (UCs) are considered the best source for short bursts of power as they have a higher power density than FCs and Batt. FCs outperform Batt in refueling and UCs in energy density, whereas UCs and Batt have fast response as well as the capability to capture energy produced during regenerative
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call