| Clean and renewable energy has gradually become the focus of environmental protection policies in developed countries.At the same time,people have also profoundly recognized the urgency and importance of environmental resource protection.The pollutants and exhaust emissions from electric vehicles seriously pollute the atmospheric environment.As a result,electric vehicles with zero energy consumption and no pollution characteristics are highly valued by most developed countries,but the average charging time of electric vehicles generally takes more than one hour.In order to effectively solve these problems that affect the endurance and charging ability of electric vehicles,it has become the focus of research in the field of automobiles.From the current research status,battery technology will hardly have substantial development in the near future.It is important to study the regenerative braking control method from the other side to improve the energy utilization rate of the car and effectively extend the driving time of the car Practical significance.This article focuses on the related technical issues of improving the efficiency of regenerative braking energy recovery.The specific research contents are as follows:(1)this paper expounds the structure and principle of regenerative braking system,analyzes the braking force distribution strategy in the braking process and the braking situation of permanent magnet synchronous motor,describes the operation situation of the motor in the braking process,and makes a mathematical derivation of the energy generated and consumed in the braking process.(2)The permanent magnet synchronous motor and vector control model,double active bridge transformation circuit model and battery equivalent circuit model are established.The feedback braking system is designed,and the pulse charging method is selected to charge the battery.Calculate the acceptable charging current of the battery during the braking process,and carry out a joint simulation experiment on the permanent magnet synchronous motor and DAB conversion circuit in MATLAB.(3)Fuzzy control is suitable for multi-variable control systems.Based on the factors that affect the efficiency of regenerative braking capacity recovery of electric vehicles,a design based on braking intensity,battery state of charge,and braking requirements is designed as an input.The fuzzy controller whose dynamic distribution coefficient is the output has formulated fuzzy control rules.According to the output regenerative braking force distribution coefficient,the ratio of the regenerativebraking force distribution is obtained.The electrical energy generated by the regenerative braking force is input to the energy storage system through the electrical energy feedback circuit In the past,the efficiency of regenerative braking was effectively improved through the formulated fuzzy control strategy.(4)Based on the ADVISOR software,an electric vehicle model was established,and three commonly used simulation conditions were selected to compare the design of the multi-factor input fuzzy control strategy.The comparison of the results showed that the three selected In the working condition,the regenerative braking energy feedback efficiency has been improved,and the maximum increase is up to 20%,which effectively verifies the effectiveness of the control method. |
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