Control of output voltage is critical for the power quality of solid oxide fuel cells (SOFCs), which is, however, challenging due to electrochemical nonlinearity, load disturbances, modelling uncertainties, and actuator constraints. Moreover, the fuel utilization rate should be limited within a safety range during the voltage regulation transient. The current research is usually appealing to model predictive control (MPC) by formulating the difficulties into a constrained optimization problem, but its huge computational complexity makes it formidable for real-time implementation in practice. To this end, this paper aims to develop a combined control structure, with basic function blocks, to fulfill the objectives with minor computation. Firstly, the disturbance, nonlinearity and uncertainties are lumped as a total disturbance, which is estimated and mitigated by active disturbance rejection controller (ADRC). Secondly, a feed-forward controller is introduced to improve the load disturbance rejection response. Finally, the constraints are satisfied by designing a cautious switching strategy. The simulation results show that the nominal performance of the proposed strategy is comparable to MPC. In the presence of parameter perturbation, the proposed strategy shows a better performance than MPC.Sustainability 2017, 9, 1517 2 of 15 the fuel utilization. Based on the benchmark model proposed in [3], it was revealed in [4,5] that the proportional-integral (PI) controller and even the H ∞ optimal control are not able to give a satisfactory performance without exceeding the safety range of the fuel utilization.To this end, the mainstream research resorts to Model Predictive Control (MPC), which is particularly suitable for constrained optimization. A data-driven linear MPC strategy was introduced in [6] based on the subspace identification. To further accommodate the nonlinearities, many nonlinear MPC (NMPC) strategyies [7-10] were developed based on much more complex heuristic models. The simulation results prove the capability of the above MPC methods under the nominal condition. However, the huge online computational requirement limits its wide application. Moreover, the implementation of MPC relies on a high-performance computer which needs to synchronously communicate with the existing Distributed Control System (DCS) through certain ports and protocols [11]. Additional hardware complexity will bring more security risks, which is not favored by the field engineers. Besides the complexity, another drawback of MPC is that the performance may deteriorate greatly in the presence of modelling uncertainties.The industrial engineers argued in [12] that use of MPC is only suitable for the applications where the process size, complexity and potential economic benefits justify the expenditure and technical support requirements. In other words, it is not necessary to adopt MPC in the cases where the control objectives can also be fulfilled by the configuration of the regular function blocks, such as simple algebraic and logic ...