Control And Energy Management Method For Semi-Active Hybrid Energy Storage Systems

With the rapid development of society,vehicles play an irreplaceable role in people's lives,which provides an important contribution to the modern transportation.Unfortunately,the emission caused by the conventional vehcles will produce the environmental pollution and the energy shortage.The new energy vehile is considered as an effective solution for the problem from the traditional cars,and it is mainly composed of electric vehicles and hybrid electric vehicles.The energy storage system is a key component of new energy vehicles.The improvement of comprehensive performance is an urgent problem to be solved.The battery has poor low-temperature characteristics,poor power characteristics,short life and fast capacity decay.With the rapid development of supercapacitor technology,its high power density and low temperature characteristics can be applied to Hybrid Energy Storage System(HESS),which is complementary to the the battery source.The battery/supercapacitor has various connection modes in HESS.In this thesis,we study the semi-active configuration of DC/DC converter and super capacitor in series.Firstly,the mechanisms and various performances of energy storage components are analyzed separately and the internal resistance equivalent model is established as well.Secondly,the topological structure of hybrid energy storage system is analyzed,including passive,active and semi-active configurations.Besides,for the semi-active hybrid energy storage system the state space average model is established by the current-voltage equation based on the current-voltage equation and the disturbance model by determining the steady state.The steady state is and the disturbance model is established as well.Finally,the convex hull function is used to deal with the saturation of the system.For the finite time stability and Lyaounov asymptotic stability of the system,the stability condition is obtained by constructing the Lyapunov-Krasovskii function and transforming the optimization problem into a numerical problem with linear matrix inequality.By comparing and analyzing the simulation results,the latter is selected to be the theoretical basis of the controller.In this thesis,the battery terminal reference current is set to 1.5A,2.4A,2.7A,2.8A,3A,the bus voltage is 20 V,the light load and the heavy load are 220? and 4? respectively.The controller simulation is completed by Matlab to ensure the robust tracking of energy storage current and the bus voltage when the load changes by current and voltage curve.For the energy management of the hybrid energy storage system,a fuzzy logic controller is designed to obtain the requirements of both energy storage components through it which according to the load demand power and the state of charge(SOC)of the energy storage component,and the energy distribution is also completed.Based on the existing top-level model of pure electric vehicle in ADVISOR,the Simulink model of pure electric vehicle with HESS was built,and the relevant parameters were configured to simulate in the U.S.urban working condition(UDDS)to verify the effectiveness of the energy management strategy.Finally,the control algorithm is optimized for the hybrid energy storage system to achieve robust control of battery/supercapacitor current and bus voltage.At the same time,the fuzzy energy controller is designed to improve the system energy utilization efficiency,and the effectiveness of the algorithm is verified by simulation.