Design and control of energy integrated SOFC systems for in situ hydrogen production and power generation

Cooperative Control of a Steam Reformer Solid Oxide Fuel Cell System for Stable Reformer Operation

Solid oxide fuel cells (SOFCs) have complex characteristics, including a long time delay, strong thermoelectrical coupling, and multiple constraints. This leads to multiple control objectives, such as efficiently controlling the power output of the stack and considering the temperature constraints of multiple high-temperature components. Dealing with multiple objectives at the same time brings challenges to the design of SOFC system control. Based on the verified high-precision system model and aiming to achieve fast response, high efficiency, and thermal management, this paper first designs a generalized predictive controller (GPC) to realize the global optimization of the system. Then, through the actual test of the individual reformer, the reformer characteristics are analyzed, the standby controller to control the reformer temperature is designed, and the thermoelectric cooperative controller is constricted with the GPC. The results show that while fast power tracking, high efficiency, and multiple temperature constraints are realized by the controller, the temperature and methane conversion rate (MCR) of the reformer are stably controlled, providing a basis for further practical experiments of the SOFC system.

Design and Implementation of the Off-Line Robust Model Predictive Control for Solid Oxide Fuel Cells

An off-line robust linear model predictive control (MPC) using an ellipsoidal invariant set is synthesized based on an uncertain polytopic approach and then implemented to control the temperature and fuel in a direct internal reforming solid oxide fuel cell (SOFC). The state feedback control is derived by minimizing an upper bound on the worst-case performance cost. The simulation results indicate that the synthesized robust MPC algorithm can control and guarantee the stability of the SOFC; although there are uncertainties in some model parameters, it can keep both the temperature and fuel at their setpoints.