Dynamic Performance Analysis of a Turbocharged PEMFC System

Abstract

Proton-exchange membrane fuel cell (PEMFC) systems are one of the most promising technologies for the decarbonization of the transportation and power sectors. This article investigates the dynamics of an innovative turbocharged PEMFC system. A detailed dynamic model of the turbocharger-proton-exchange membrane fuel cell (TC-PEMFC) is developed in Matlab-Simulink. This model is used to study the dynamic performance of the system, considering the fluid-dynamic and thermal transients of its components. At first, the model is used to simulate the response of the TC-PEMFC to step changes of multiple input variables: openings of fuel valve and humidifier bypass valve, rotational speeds of turbocharger (TC), blower, and cooling pump. These simulations highlight the strong sensitivity of the system to the fuel valve opening, making the need for a feedback controller clear. Many control logics are then implemented on the model to keep the operative parameters of the TC-PEMFC within an acceptable range. The dynamic model is used to simulate the performance of the TC-PEMFC system during different power load ramps. From the results of these simulations, it is possible to assess the effectiveness of each controller and to verify the compliance of all the system constraints. During load increases, proper operation of the system is always guaranteed, whereas load reductions are limited by the possibility of compressor surge (35 A/s of maximum ramp rate). To overcome this limit, a possible modification to the control logics is tested in the final part of the study.