| Environmental pollution and energy shortage are the problems of modern society,and fuel cell as a clean and efficient energy source has become a current research hot spot.This paper takes fuel cell+power battery+super capacitor hybrid power system vehicle as the research object,selects the components according to the dynamics requirements,then matches the vehicle components parameters and builds the vehicle dynamics model,develops the energy management strategy to meet the vehicle dynamics requirements,and designs the energy management strategy integrating multi-objective optimization because it is difficult to evaluate the two performance indexes by one equation.The main research components are:(1)Selecting,matching parameters and building models for fuel cells,power cells,super capacitors and motors according to the vehicle dynamics requirements and operating conditions,and providing theoretical support for the application of energy management strategies by combining ADVISOR.(2)Propose a dual fuzzy control strategy for series-type power distribution.According to the efficiency characteristics of each energy source of the fuel cell hybrid power system,it is simplified for the complex problem of energy distribution of multiple energy sources,so that the logic of its control becomes simple and clear.With the objectives of reducing the fuel consumption of the whole vehicle,reducing the number of starts and stops of the fuel cell and reducing the current inrush of the Li-ion battery,a control scheme with a dual fuzzy control strategy is designed,i.e.the main-fuzzy controller controls the fuel cell to ensure the power output of the fuel cell;the sub-fuzzy controller controls the Li-ion battery and the super capacitor to control the power output of both and the braking energy recovery;(3)A Pareto multi-objective optimal energy management strategy based on dual fuzzy control is proposed.To address the problems of fuzzy control relying on subjective experience and the difficulty of fusing multiple performance indicators,an improved non-dominated sorting genetic algorithm(NSGA-II)is used to solve the multi-objective problem with the objective of equivalent energy consumption and equivalent energy source performance degradation of three energy sources,and the dual fuzzy controller affiliation function is continuously optimized to finally obtain multiple optimized solutions to form a Pareto non-inferiority solution set.Finally,a joint simulation model is established using MATLAB and ADVISOR to simulate and analyze the strategy proposed in this paper and other strategies.Through the joint simulation of MATLAB and Advisor,the dual fuzzy control and multi-objective optimized dual fuzzy control are compared and analyzed with power following control and fuzzy control under WLTC operating conditions,and the results show that the fuel cell hybrid vehicles with dual fuzzy control strategy meet the dynamics requirements,and the fuel economy is generally improved compared with power following control and single fuzzy control strategy by 6.7%,6.4%,and the average current endured by the Li-ion battery is also reduced.The Pareto multi-objective optimization EMS based on dual fuzzy control can reduce the equivalent energy consumption by 2.1% and the equivalent energy source performance degradation by 86.4%,verifying that the strategy proposed in this paper has a better energy optimization effect as well as a more effective improvement of the fuel cell performance degradation,thus,solving the problem of difficult integration of two conflicting performance indicators.In addition,the method in this paper can choose different and appropriate Pareto non-inferiority solutions to suit the specific driving scenario of the vehicle,providing more solutions to target the vehicle energy management problem,and the proposed strategy has a larger scope of application compared with other control strategies. |
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