Comparison of three different control strategies for load-change and attenuation of solid oxide fuel cell system

Solid oxide fuel cell (SOFC) with a lot of advantages, such as high efficiency, low emission and great fuel compatibility, has broad application prospects in many fields. However, an appropriate control strategy is necessary for SOFC systems, which could not only maintain high system efficiency during load-change, but also supplement power after attenuation to extend system service life. In the article, three different control strategies are proposed, in which fuel flow, fuel utilization and cell voltage are controlled as constants respectively. The performance and applicability of strategies for load-change and cell degradation are evaluated through experiment data and simulations. Meanwhile, stack temperature, voltage, fuel utilization and efficiency are selected as main constraints to analyze the application scope of strategies. And in load increasing process of a 1 kW SOFC combined heat and power (CHP) system fed with methanol, the strategies are adopted to verify their effectiveness.