Research On Key Technologies Of Energy Management System And High Voltage Safety Strategy Of Pure Electric Vehicles

The energy management system of pure electric vehicles is the integration ofdistribution and optimization of pure electric vehicles, battery management system of pureelectric vehicles and regenerative braking energy recovery system. The core context of thepaper uses fuzzy control theory to research the key technologies of energy managementsystem of pure electric vehicles. The research result had been used in products. The highvoltage safety technology is one of the key technologies of pure electric vehicles. Firstly,the paper analyses the composition and function of high voltage safety system. Thetraditional passive insulation resistance detection method has been substitute for newinsulation resistance detection because of its defect. Secondly, the paper designs the delaycircuit according to the requirement of the pure electric vehicle high voltage safety systemwhich uses in the products.The range for one charging of pure electric vehicle is short which affects itsperformance. The paper divides pure electric vehicles into three driving modes, powermode, economy mode and normal mode. The power mode pays more attention to improvethe power performance of pure electric vehicles. The motor controller responses morerapidly to the accelerator pedal. And the motor outputs higher torque as current speed whichmakes the pure electric vehicles improve the ability of acceleration and climbing.Thecontrol target of economy mode is the maximum running range which makes the motor andbattery work at the high efficient area. The normal mode is the compromise of other twomodes. The paper uses fuzzy control method to design vehicle control unit and test thevalidity of the results through the real car test and the simulation of matlab software.The battery management system is the core part of the energy management system ofpure electric vehicles. The acquisition system gets the information from BMS which affectsthe estimation of the remaining running range and the works of high voltage safety system.The paper deals with time-delay of the acquisition system of BMS, which uses the T-Sfuzzy state feedback control method to design the stability controller. The experimentresults show that the control method is effective. Further more, the paper analyses the stability of two dimensional discrete time system base on Roesser model to deal with thetime-delay problem on image transmission of pure electric vehicle monitor system. Inaddition, the problem of the acquisition system of BMS with actuator faults can make thecontrol system not stability. The paper designs a reliable controller base on T-S fuzzysystem. It has different control structure which can introduce more control gain matricesand the obtained reliable control conditions are given in terms of linear matrix inequalities.Therefore, the conservatism of the existing results could be obviously reduced on accountof the underlying measures. Finally, the effectiveness of the proposed approach isillustrated by means of numerical experiments.The regenerative braking energy recovery system of pure electric vehicles is effectivefor increasing the running range of the vehicles. The paper establish the model of theregenerative braking energy recovery system of pure electric vehicles and use the controlstrategy of minimum braking power distribution which can reduce the energy consumption,and improve the utilization efficiency and braking energy. The result had been modelingand simulating by dual-energy source of pure electric vehicles.The thesis analyses the defects of traditional passive insulation resistance detectionmethod, and proposes a new type of active detection method. The new method can be usedeffectively under the situation of positive bus and negative bus symmetrical fault. Inaddition, in order to protect the high voltage parts of pure electric vehicles, it designs highvoltage delay circuit, and applies to the products.