Coordinated Optimal Control Of Mutil-Stack Fuel Cells And Hybrid Energy Management

In recent years,environmental protection and sustainable development have become the key content of my country’s economic and social development process,and the application of new energy systems in various fields is gradually becoming an important way to achieve energy conservation and emission reduction.In new energy systems,hydrogen fuel cells have the advantages of environmental protection,high efficiency and safety compared with traditional energy conversion devices,and have been widely used in high-power practical projects such as locomotives,passenger cars,cruise ships and trams.Therefore,in order to meet the needs of fuel cell markets,it is necessary to solve the problems of insufficient output power of single fuel cell and slow dynamic response of pure fuel cell system,this paper studies multi-stack fuel cell system and multi-stack fuel cell power system considering auxiliary power.Through the optimization and optimal control of the power distribution of multi-stack fuel cell system and hybrid power system,the fuel cell performance and system operation and maintenance cost are optimized.The main research work is as follows:In order to solve the problem that multi-stack fuel cell system is easily affected by the operating environment and other factors,the maximum operating efficiency point of the system may change.This paper proposes a tracking control method for the maximum efficiency point of multi-stack fuel cell system based on online identification.This method utilizes the real-time online fitting capability of EKF to quickly realize the identification of multi-stack fuel cell system efficiency/power curve,so as to estimate the maximum efficiency point power of the system in real time.And through the power distribution method to realize the reasonable distribution of the output among the various stacks to achieve the purpose of maintaining stable operation of multi-stack fuel cell system at the maximum efficiency point,and the RT-LAB simulation test platform verifies the effectiveness of this method in improving system efficiency.Aiming at the inconsistency of aging degree among multi-stack fuel cells,this paper proposes an adaptive power distribution method for multi-stack fuel cell system considering stack performance degradation.The method is to construct a fuel cell difference function based on the experimental test data to reflect the aging of the fuel cell in operation according to the ratio between the measured real-time voltage and the ideal voltage.Finally,this amount of variation is combined with a droop control strategy.It can adaptively adjust the output power among stacks to maintain consistency of the performance degradation of multi-stack fuel cell system.In this paper,the effectiveness and feasibility of the proposed method are verified by the RT-LAB hardware-in-the-loop simulation test platform.In order to give full play to the advantages of each power source and prolong the service life of the stack,a multi-stack fuel cell hybrid power system is constructed.In order to ensure reasonable system power distribution and minimum hydrogen consumption,an energy management method for fuel cell hybrid power system based on two-layer decision-making is proposed.The method analyzes fuel cell efficiency interval and change of the hydrogen consumption curve,and adopts a segmented solution method to achieve the purpose of high real-time operation efficiency and low system hydrogen consumption of the fuel cell in different intervals of the required power.Finally,the effectiveness of the proposed method is verified by RT-LAB platform.Aiming at the economic loss caused by the aging of fuel cells,an energy management method for mutil-stack fuel cell hybrid power system that takes into account hydrogen consumption and fuel cell life loss is proposed by constructing an objective function based on system economy as an evaluation index.The method analyzes the influence of the fuel cell on its aging in four modes: start-stop,acceleration,idle speed and variable load.In this paper,the problem of life loss is transformed into the problem of minimum cost,and then according to the equivalent hydrogen consumption theory,the optimal cost function of the system is established,and the output power of each power source is solved by the Salp Swarm Algorithm.Finally,it is verified on the RT-LAB platform that the method not only prolongs the service time of the fuel cell,but also effectively reduces the system operation and maintenance cost.