Optimization with Dynamic Programming of the Energy Management Strategy for a Fuel Cell Hybrid Heavy-Duty Truck Minimizing Hydrogen Consumption and Degradation

Achieving sustainable mobility requires the implementation of alternative and carbon-free technologies, especially in the sector of heavy-duty vehicles where powertrain electrification is challenging due to the high loads and long distances involved. In this context, hydrogen proton exchange membrane (PEM) fuel cell technology is considered a promising power source for heavy-duty hybrid electric vehicles. At the fuel cell level, the membrane electrode assembly (MEA) degradation and the system thermal management remain two major areas of research, that can be addressed not only with the development of new materials but also with the implementation of optimal control strategies. Working under operating points that lead to MEA aging and performance degradation can reduce the lifetime of the fuel cell with repercussions on the vehicle’s total cost of ownership. Typical fuel cell powertrains are hybridized in a parallel configuration with a battery, which requires solving an energy management control problem to define the optimal power split among the two power sources. For a given powertrain design and sizing of the components, different control strategies can greatly impact the performance of the system and its durability. In this work, a fuel-cell hybrid electric heavy-duty truck is modeled, and Dynamic Programming is used to find the optimal control strategy for the fuel cell operation that minimizes hydrogen consumption. At the same time, by limiting the current ramp rate and fuel cell shutdowns, the aim is to reduce fuel cell aging, enabling operation under minimal degradation conditions and higher efficiencies. Dynamic Programming off-line simulations provide an optimal benchmark control strategy for the fuel cell, that can be leveraged for the development of real-time implementable controllers. The simulation results show that introducing limitations on the current ramp rate and fuel cell shutdowns slightly affects energy consumption while greatly reducing the aging and degradation of the fuel cell.