Research On Power Control Of Fuel Cell Compound Dual Energy Source System

The loader has the advantages of fast working speed,flexible action,good mobility and high production efficiency.However,the traditional loader uses diesel engine as the power source.Under the current situation of energy shortage and bad environment,it is of great theotretical significance to study the new energy loader.Hydrogen energy is known as the ‘ultimate energy’ in the 21 st century,and it is of great significance to study the fuel cell loader.Due to the limitation of battery technology and its own characteristics,the pure fuel cell loader can not meet all working conditions.In this paper,a composite power system driven by the super capacitor of fuel cell and auxiliary power is proposed.The power transmission scheme is designed and the intelligent energy management strategy is studied.Firstly,the paper analyzes the working condition characteristics and performance parameters of the existing traditional loaders,designs the power system of the fuel cell composite power wheel loader,and puts forward the parallel fuel cell composite power system.According to the characteristics of the loader,the fuel cell system and super capacitor are selected and the parameters are matched.Secondly,the fuel cell model,super capacitor model,motor model and hydraulic system model are established by Matlab/Simulink software.According to the characteristics of fuel cell composite power system and loader working condition,the working mode of composite power supply is designed.Based on the wavelet change of power distribution,the three-layer Haar wavelet theory is used to control the power layer by layer,which solves the problem that the output power of fuel cell is flat and the response is slow;the super capacitor ‘peak cutting and valley filling’ is fully used to deal with the power with sharp change and peak value,so as to improve the working life of fuel cell system.A fuzzy logic control strategy is designed.Mamdani fuzzy logic controller is established by taking the processed load power and super capacitor SOC as the input and fuel cell power as the output.According to the expert’s experience and opinion,the control rules are established in four working modes,so that the controller can control the power distribution factor to distribute the power flow of the dual energy sources and further improve the economy of the whole system.Finally,particle swarm optimization algorithm is used to optimize the control system in real time.By summing up the problem into three optimization constraints,the effect of the ab-bove problems on different parameters of particle swarm optimization algorithm is tested,the best group of parameters is selected,and the simulation results are analyzed.The results show that the structure of the proposed fuel cell composite power supply system is feasible,and the effectiveness and feasibility of using various control strategies are proved.Compared with the fuzzy logic strategy,the wavelet fuzzy logic strategy and the optimized wavelet fuzzy logic strategy,the curve is simulated.Compared with the fuzzy logic strategy,the wavelet fuzzy logic strategy effectively reduces the fuel cell power fluctuation.The output power curve of the fuel cell is more gentle and drops about 5% year-on-year,and the supercapacitor SOC change more violently and maintains near 0.6.After optimization,the output of fuel cell is about 2% lower than before.