Incremental Step Reference Governor for Load Conditioning of Hybrid Fuel Cell and Gas Turbine Power Plants

Abstract

A hybrid solid oxide fuel cell and gas turbine (SOFC/GT) system exploits the complementary features of the two power plants, where the GT recuperates the energy in the SOFC exhaust stream and thereby boosting the overall system efficiency. Through model based transient analysis, however, it is shown that the intricate coupling dynamics make the transient load following very challenging. Power shutdown has been observed when the load is changed abruptly in the generator. In this work, a novel closed-loop reference governor controller is proposed to mitigate the shutdown phenomenon. The reference governor utilizes the region of attraction of a reduced order SOFC/GT model to determine if an incremental step change is allowable, i.e., it does not cause a shutdown. It is shown that with a moderate computational cost, the speed of the hybrid power system response can be improved significantly compared to the fastest conventional load filter. Several design parameters, such as the sampling rate and incremental step-size, are also explored to understand the trade-offs between computational complexity and performance improvement.

Adaptive Tracking Constrained Controller Design for Solid Oxide Fuel Cells Based on a Wiener-Type Neural Network

“…According to the previous research [7][8][9][10], the working principles of fuel cells are essentially similar. In short, the SOFC system contains the fuel process part and the fuel cell stack.…”

“…Against this background, many researchers have considered fuel cell electricity generation with higher energy efficiency, which produces water, heat, less noise, no radiation and negligible amounts of pollutants [1][2][3][4][5]. The solid oxide fuel cell (SOFC) is a type of fuel cell that uses solid oxide material as the electrolyte to send negative oxygen ions from the cathode to the anode, where a chemical reaction related to the electrochemical oxidation occurs [6][7][8][9][10]. SOFCs have many advantages, such as flexibility in selecting fuel, long-term stability and no need for an expensive catalyst.…”

Reference governor for constrained spacecraft orbital transfers

“…This approach has been adopted in online prediction based reference governors 3,19 and the initial variant of IRG. 9 The simulations were performed with the same parameters as in Section 6. The prediction horizon was set to 10 h with constraints checked for violation every 20 s over the predicted trajectory.…”

“…For the nominal controller in our orbital transfer problem, we choose a Lyapunov-based controller, 2 derived based on Gauss variational equations (GVEs), for which we highlight the connection between persistence of excitation conditions and closed-loop trajectories rate of convergence to the target orbit; this connection is not made explicit in the prior literature. 2,8 We then propose a modification of an incremental reference governor (IRG) strategy 9 that we refer to as a multi-step multi-mode incremental reference governor (m 2 IRG) to handle constraints on minimum radius of periapsis, thrust and eccentricity. The IRG 9 is a variant of the reference/command governor intended for situations where the available computational time is insufficient to be able to perform the full optimization of the reference command (in our case, the reference command will be defined by five orbital elements of the target orbit).…”

Constrained Control for Cloud Robotic Under Time Delay Based on Command Governor With Interval Estimation

“…The quadratic programs are worked out through Matlab functions in our simulations. The implementation of QP algorithm could be different for various practical systems, such as bisections method [14] and the incremental step strategy [24]. More applications can be found in [10], [21], [22] and references there in.…”