Control System Based on Anode Offgas Recycle for Solid Oxide Fuel Cell System

Abstract

The conflicting operation objectives between rapid load following and the fuel depletion avoidance as well as the strong interactions between the thermal and electrical parameters make the SOFC system difficult to control. This study focuses on the design of the decoupling control for the thermal and electrical characteristics of the SOFC system through anode offgas recycling (AOR). The decoupling control system can independently manipulate the thermal and electrical parameters, which interact with one another in most cases, such as stack temperatures, burner temperature, system current, and system power. Under the decoupling control scheme, the AOR is taken as a manipulation variable. The burner controller maintains the burner temperature without being affected by abrupt power change. The stack temperature controller properly coordinates with the burner temperature controller to independently modulate the stack thermal parameters. For the electrical problems, the decoupling control scheme shows its superiority over the conventional controller in alleviating rapid load following and fuel depletion avoidance. System-level simulation under a power-changing case is performed to validate the control freedom between the thermal and electrical characteristics as well as the stability, efficiency, and robustness of the novel system control scheme.

A Review of X-ray Photoelectron Spectroscopy Technique to Analyze the Stability and Degradation Mechanism of Solid Oxide Fuel Cell Cathode Materials

“…However, reduction of the operating temperature below 600 °C results in high electrolyte ohmic resistance and electrode polarization resistance, resulting in power loss [ 7 , 8 , 9 ]. These phenomena can be attributed to the physicochemical processes of the SOFC system, such as electrochemical reaction, heat conduction, transport of ions, electrons, and fuel, and convection [ 10 ]. Therefore, the reaction kinetics of individual components in SOFC contributes to the overall cell performance.…”

Designing Hydrogen and Oxygen Flow Rate Control on a Solid Oxide Fuel Cell Simulator Using the Fuzzy Logic Control Method

“…Interactions with each other in many cases, such as stack temperature, furnace temperature, system flow, and system power. For electricity problems, the decoupling control scheme shows its advantages compared to conventional controllers in alleviating fast load accumulation and avoiding fuel depletion [8].…”

“…Some of the references above [5][6][7][8][9][10] show software-based SOFC stack simulations. Some of them use MATLAB.…”

“…All of these are assumed as shown in Table 3. Partial pressure is calculated based on Equations (6), (8), and (10), while calculating the prototype of the SOFC simulator [7,13]. This equation is still in the form of a transfer function.…”