Advanced Passivity-Based Control for a Fuel Cell/Super-Capacitor Hybrid Power System

This article deals with the power flow control in a hybrid power system, which is composed of a fuel cell, photovoltaic system and a super capacitor. The super capacitor has been employed with an aim to ameliorate the performance of the hybrid power system. In addition, it takes into account the energy fluctuations of photovoltaic energy sources and the slow dynamic of the fuel cell. Each source is connected to a DC/DC converter and their outputs are connected to a common DC-link and they supply a DC load. Furthermore, an energy management algorithm has been carried out in order to commonly share the power between the sources and the load. The proposed energy management method shows its flexibility, and an efficient energy conditioning between different sources is guaranteed in case of multi-source system. The main originality of this work lies in the use of AC-link partial resonant DC–AC converter topology to interface hybrid system and to inject the excess of energy to the grid. In this article, the system description, the control and the modeling of DC/DC converters and the AC-link converter are provided. Finally, simulations under Matlab/Simulink are shown in order to validate the effectiveness of the proposed control strategy and the energy management algorithm. An implementation on real-time using dSpace 1104 is presented to illustrate the feasibility of the proposed control strategy.

Download Full-text

Optimization of the Fuel Cell Renewable Hybrid Power System Using the Control Mode of the Required Load Power on the DC Bus

Energies ◽

10.3390/en12101889 ◽

2019 ◽

Vol 12 (10) ◽

pp. 1889 ◽

Cited By ~ 8

Author(s):

Nicu Bizon ◽

Valentin Alexandru Stan ◽

Angel Ciprian Cormos

Keyword(s):

Energy Source ◽

Fuel Cell ◽

Power System ◽

Control Mode ◽

Variable Load ◽

Hybrid Power System ◽

Hybrid Power ◽

Load Power ◽

Load Demand ◽

Dc Bus

In this paper, a systematic analysis of seven control topologies is performed, based on three possible control variables of the power generated by the Fuel Cell (FC) system: the reference input of the controller for the FC boost converter, and the two reference inputs used by the air regulator and the fuel regulator. The FC system will generate power based on the Required-Power-Following (RPF) control mode in order to ensure the load demand, operating as the main energy source in an FC hybrid power system. The FC system will operate as a backup energy source in an FC renewable Hybrid Power System (by ensuring the lack of power on the DC bus, which is given by the load power minus the renewable power). Thus, power requested from the batteries’ stack will be almost zero during operation of the FC hybrid power system based on RPF-control mode. If the FC hybrid power system operates with a variable load demand, then the lack or excess of power on the DC bus will be dynamically ensured by the hybrid battery/ultracapacitor energy storage system for a safe transition of the FC system under the RPF-control mode. The RPF-control mode will ensure a fair comparison of the seven control topologies based on the same optimization function to improve the fuel savings. The main objective of this paper is to compare the fuel economy obtained by using each strategy under different load cycles in order to identify which is the best strategy operating across entire loading or the best switching strategy using two strategies: one strategy for high load and the other on the rest of the load range. Based on the preliminary results, the fuel consumption using these best strategies can be reduced by more than 15%, compared to commercial strategies.

Download Full-text