Study On The Design And Control Strategy Of Hybrid Electric Power System On HEV

With the steady and continuous development of the economy,the automobile becomes more and more popular,which cause more and more serious energy and environment crisis.This has been attached great attention to governments.In order to solve the crisis,hybrid electric vehicle came into being and developed rapidly because that it is low power and low pollution.With the great development of hybrid electric vehicle,the power battery problem which limits the development of the hybrid electric vehicle is becoming more prominent.As in most kinds of hybrid electric vehicles,there is only one single-vehicle power supply—power batteries,and to hybrid electric vehicle,the requirement of output power changed greatly,it needs charge and discharge in a few seconds,the characteristics of the battery determines it can not fit to this in the low-temperature.The power battery needs to be made very large to provide large current and high power,so the weight and the cost of the battery which attached to the vehicle is also increased.The specific power of ultra-capacitor is very large,but the specific energy is very small,it's not fit to be as a single-power supply. Studies have shown the hybrid electric power which includes battery and ultra-capacitor has a strong pulse performance,and it is suitable for automotive power.How to show the excellence in the hybrid electric power,such as high efficiency,power,and fast dynamic response,a variety of working conditions,high precision and so on,this is a big challenging thing and also a highly practical significance of the study.This thesis studies the hybrid electric power,in the first,we analysis the working principle and electrical characteristics of power batteries. Then we studies the parameters of the power battery system.Design the structure of hybrid electric power,and the component parameters of regenerative braking system.We obtained the braking performance table through the simulation.The discussed several kinds of bidirectional DC/DC converters in detail,and selected a two-way half-bridge converter, define the component parameters,the hardware of the converter circuit and software program flow chart finally.Based on logic threshold control strategies,the article introduces the fuzzy control strategy,through modeling and simulating on the two control strategies,we find that we find that compared with the logic threshold control strategies,fuzzy logic control strategy have a better result,high economic,low pollution.