0
Research Papers: Gas Turbines: Controls, Diagnostics, and Instrumentation

# Pressurized SOFC Hybrid Systems: Control System Study and Experimental Verification

[+] Author and Article Information
Luca Larosa

TPG,
University of Genoa,
Via Montallegro 1,
Genoa 16145, Italy
e-mail: luca.larosa@unige.it

Alberto Traverso

TPG,
University of Genoa,
Via Montallegro 1,
Genoa 16145, Italy
e-mail: alberto.traverso@unige.it

Mario L. Ferrari

TPG,
University of Genoa,
Via Montallegro 1,
Genoa 16145, Italy
e-mail: mario.ferrari@unige.it

Valentina Zaccaria

TPG,
University of Genoa,
Via Montallegro 1,
Genoa 16145, Italy
e-mail: valentina.zaccaria@CONTR.NETL.DOE.GOV

Contributed by the Controls, Diagnostics and Instrumentation Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 14, 2014; final manuscript received July 30, 2014; published online October 7, 2014. Editor: David Wisler.

J. Eng. Gas Turbines Power 137(3), 031602 (Oct 07, 2014) (8 pages) Paper No: GTP-14-1390; doi: 10.1115/1.4028447 History: Received July 14, 2014; Revised July 30, 2014

## Abstract

In this paper, two different advanced control approaches for a pressurized solid oxide fuel cell (SOFC) hybrid system are investigated and compared against traditional proportional integral derivative (PID). Both advanced control methods use model predictive control (MPC): in the first case, the MPC has direct access to the plant manipulated variables, in the second case, the MPC operates on the setpoints of PIDs which control the plant. In the second approach, the idea is to use MPC at the highest level of the plant control system to optimize the performance of bottoming PIDs, retaining system stability and operator confidence. Two MIMO (multi-input multi-output) controllers were obtained: fuel cell power and cathode inlet temperature are the controlled variables; fuel cell bypass flow, current and fuel mass flow rate (the utilization factor kept constant) are the manipulated variables. The two advanced control methods were tested and compared against the conventional PID approach using a SOFC hybrid system model. Then, the MPC controller was implemented in the hybrid system emulator test rig developed by the thermochemical power group (TPG) at the University of Genoa. Experimental tests were carried out to compare MPC against classic PID method: load following tests were carried out. Ramping the fuel cell load from 100% to 80% and back, keeping constant the target of the cathode inlet temperature, the MPC controller was able to reduce the mismatch between the actual and the target values of the cathode inlet temperature from 7 K maximum of the PID controller to 3 K maximum, showing more stable behavior in general.

<>

## Figures

Fig. 1

Emulator test rig at University of Genoa

Fig. 2

System emulator layout and interface to the fuel cell stack real-time model

Fig. 3

Dynamic model layout

Fig. 4

Functional interface between model and plant

Fig. 5

Strategy of MPC

Fig. 6

Flow diagram of Matlab MPC toolbox [21]

Fig. 7

MPC MIMO variables

Fig. 8

MPC/PID MIMO variables

Fig. 9

Simulation: fuel cell load ramp from 100% to 80% and back

Fig. 10

Simulation: fuel cell load step from 100% to 90%

Fig. 11

Simulation: fuel cell inlet temperature during load ramp from 100% to 80% and back

Fig. 12

Simulation: fuel cell inlet temperature during load step from 100% to 90%

Fig. 13

Simulation&Noise: fuel cell load ramp from 100% to 80% and back

Fig. 14

Simulation&Noise: fuel cell inlet temperature during load ramp from 100% to 80% and back

Fig. 15

Simulation&Noise: fuel cell load step from 100% to 90%

Fig. 16

Simulation&Noise: fuel cell inlet temperature during load step from 100% to 90%

Fig. 17

Experiments: fuel cell load ramp from 100% to 80% and back

Fig. 18

Experiments: fuel cell inlet temperature during load ramp from 100% to 80% and back

## Discussions

Some tools below are only available to our subscribers or users with an online account.

### Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections