Research On Power System And Energy Management Of Electric Vehicle

With the change of the world energy pattern and the concept of green development deeply rooted in the hearts of the people,electric vehicles using clean energy will have a broad development prospect.The power supply system is the core of the electric vehicle,providing energy for the motor and other electronic loads in the car.Electric vehicle power supply system mainly consists of auxiliary DC system and power supply system.This paper mainly studies from these two aspects.The auxiliary DC system provides power to the low-voltage load in the vehicle and generally consists of an auxiliary battery and a related DC-DC converter.In this paper,the half-bridge DC-DC converter is used to carry out the energy transfer between the power battery and the auxiliary battery.A two-stage charging control composed of constant current mode and constant voltage mode is designed.A method of automatic switching between the two modes is proposed according to the change of terminal voltage of the auxiliary battery,and the relevant control is verified by simulation and experiment.In this paper,the composite power source(power battery + super capacitor)is used as the power source to provide driving energy for the motor and solve the problems caused by the single battery as the power source.The composite power supply adopts a semi-active structure,and a three-phase coupled inductance interleaved parallel converter is designed as a component of the structure.This converter has high power density and has advantages in steady state and dynamic performance compared with ordinary interleaved parallel converters.In terms of converter control,a decouplingbased current sharing control is designed,and the effectiveness of the control and the advantages of the converter are verified through simulation and experiments.In this paper,the energy distribution strategy of the composite power supply is studied.Firstly,the secondary development is carried out in the ADVISOR simulation software to establish a vehicle model with a composite power supply system,and then an energy management control strategy combining fuzzy and filtering is proposed.In the simulation,it is verified that the control strategy can achieve the "peak-shaving and valley-filling" function of the supercapacitor.Compared with the single battery as the power source,the composite power source can extend the driving range and life of the power battery.In the experiment,the effectiveness of the proposed energy management control strategy is verified,which can reduce the fluctuation of power battery output.Finally,a power supply with an offline flyback converter as the main body is designed,which converts single-phase AC power to +5V and other voltage levels of DC power to complete the power supply for the hardware required by the experimental platform.The paper has 65 pictures,5 tables,and 81 references.