Integration of a Multi-Stack Fuel Cell System in Microgrids: A Solution Based on Model Predictive Control

Abstract

This paper proposes a multi-objective model predictive control (MPC) designed for the power management of a multi-stack fuel cell (FC) system integrated into a renewable sources-based microgrid. The main advantage of MPC is the fact that it allows the current timeslot to be optimized while taking future timeslots into account. The multi-objective function solves the problem related to the power dispatch at time that includes criteria to reduce the multi-stack FC degradation, operating and maintenance costs, as well as hydrogen consumption. Regarding the scientific literature, the novelty of this paper lies in the proposal of a generalized MPC controller for a multi-stack FC that can be used independently of the number of stacks that make it up. Although all the stacks that make up the modular FC system are identical, their levels of degradation, in general, will not be. Thus, over time, each stack can present a different behavior. Therefore, the power control strategy cannot be based on an equal distribution according to the nominal power of each stack. On the contrary, the control algorithm should take advantage of the characteristics of the multi-stack FC concept, distributing operation across all the stacks regarding their capacity to produce power/energy, and optimizing the overall performance.

Hybrid Intelligent Modelling in Renewable Energy Sources-Based Microgrid. A Variable Estimation of the Hydrogen Subsystem Oriented to the Energy Management Strategy

“…The complete scheme of the microgrid with all the systems and their interconnection is shown in Figure 1 [40]. The dataset used by authors to obtain the hybrid model corresponds to experimental tests carried out in the real microgrid presented in [41].…”

Propuesta multiobjetivo basada en lógica borrosa para microrredes renovables residenciales hibridadas con hidrógeno

“…La reducida vida útil, altamente dependiente de las condiciones de operación, de las pilas de combustible implica la necesidad de acciones de control locales que eviten, en la medida de lo posible, altas degradaciones del sistema de pila de combustible multi-stack [5]. Por otra parte, la baja eficiencia del ciclo de hidrógeno hace necesario considerar la potencia de operación, número de ciclos y el tiempo de operación.…”

“…Para las microrredes renovables, entre los sistemas de almacenamiento más prometedores, se encuentran los basados en baterías hibridados con los basados en hidrógeno, que se componen generalmente (si la producción, almacenamiento y consumo se da en la misma red) por un electrolizador, un tanque de almacenamiento y un sistema de pila de combustible, ya sea de estructura simple o modular [3]. Si bien respecto a la estructura simple, la estructura modular ofrece mejor comportamiento del sistema de pila de combustible en términos de tiempo de vida y eficiencia [4], requieren un mayor control complejo debido a que añaden un mayor número de variables al sistema de gestión energética (SGE) [5]. No obstante, como el SGE puede abordar el problema de control con mayor grado de libertad, se hace más fácil la gestión de la microrred tanto desde el punto de vista técnico (satisfaciendo la demanda) como desde el punto de vista económico (haciéndola más eficiente y rentable) [6].…”

Minimum hydrogen consumption power allocation strategy for the multi-stack fuel cell (MFC) system based on a discrete approach

“…Calderon (Calderón et al, 2020) proposes a generalized state space model for MFC systems, where the power allocation is based on the degree of stack degradation, combined with an MPC controller for reducing the system degradation. Jian (Jian and Wang, 2022) presents a fuel cell electric vehicle (FCEV) power system model to MFC systems to increase system redundancy.…”