Model Based Investigation on Drive Train Performance of a Heavy-Duty Fuel Cell Truck Focusing on the Fuel Cell Air Delivery System

Fuel cells are considered to be a crucial building block of future hydrogen-based energy utilization systems. Heavy-duty vehicles, such as buses and trucks, with fuel cell drive trains can already today provide not only ecologic but also economic benefit. For the proper dimensioning and designs of fuel cell drive trains the modeling and simulation of these vehicles is indispensable. This paper outlines some results of the investigations conducted in the research project BZ_Turbolader by TU Chemnitz, IHI Charging System Intl GmbH (ICSI) and Silver Atena GmbH. These partners cooperated in order to develop an Air compressor that is driven by an electric motor and allows Recuperation (AC+eR) to efficiently supply air for the fuel cell. Its influence on the performance of the fuel cell system, the overall power train and vehicle efficiency is investigated. A forward simulation in MATLAB/Simulink has been implemented comprising all essential subsystems of a 40t heavy-duty fuel cell truck. Since this project focused on the air delivery system of the fuel cell one crucial sub-model is the air path submodel consisting of compressor and turbine, its electrical power unit, but also other flow elements such as back-pressure valves and by-passes, humidifiers, air coolers and water separators. The air path model, developed by ICSI, has been programmed in MATLAB® to keep effort and costs for users low. In a first step, a 0-dimensional thermodynamics and flow simulation approach using orifices and flow volumes was chosen to have lowest simulation times while still having dynamic system behavior modelled. Silver Atena implemented the submodels for the AC+eR motor and inverter and other power electronics, such as DC/DC converters. TU Chemnitz implemented the vehicle model and integrated the air path and electrical models developed by ICSI and Silver Atena, respectively.