Research On The Motor Drive Technology And Braking Energy Recovery Control Strategy Of New Energy Electric Vehicles

In the 21 st century,with the global energy crisis and environmental problems becoming increasingly prominent,people are looking for new energy sources to reduce dependence on traditional fossil energy.In the automotive industry,new energy electric vehicles also conform to the trend of the times and become a hot spot of current research.At present,the bottleneck of the development of new energy electric vehicles is still the issue of durability.Therefore,starting from the purpose of energy saving and emission reduction,this paper studies the motor drive system and braking energy recovery control strategy of new energy electric vehicles.In the part of motor drive system of new energy electric vehicle,PMSM is chosen as the driving motor of new energy electric vehicle.Based on the mathematical model of PMSM,the basic principle of space vector control technology is analyzed,and the speed-current double closed-loop control of PMSM is completed.On this basis,a hardware test platform for automotive motors is built.The test platform uses common DC bus technology to achieve the energy-saving effect of the platform.Then the hardware design of the motor drive part of the test platform is introduced.A pump circuit is used to solve the problem that the traditional bootstrap circuit can not achieve full duty ratio.In the control strategy of braking energy recovery for new energy electric vehicles,the braking process of the vehicle is analyzed based on the braking mechanics of the vehicle.An ideal two-wheel model of a vehicle under braking condition is established,and the restraint of front and rear wheel braking force is analyzed.Then,considering that in order to meet the requirement of regenerative energy recovery as much as possible and ensure the safety and stability of automobile braking at the same time,this paper takes energy recovery effect and braking stability as the direction of multi-objective optimization,and also considers the constraints of battery SOC,motor external characteristics and ECE regulations,establishes a multi-objective decision-making model.For solving the multi-objective decision-making model,this paper proposes an improved MOPSO algorithm based on the traditional MOPSO algorithm,in order to obtain the Pareto optimal solution set of the multi-objective decision-making model.Then,the TOPSIS evaluation strategy in economics is used for reference to complete the comprehensive evaluation of Pareto optimal solution,and the optimal solution of this multi-objective decision model is selected to obtain the optimal control strategy in this paper.Finally,the control strategy calculated under the multi-objective decision-making model is loaded into Cruise software by using Cruise and Simulink simulation,and the effect of braking force distribution strategy is verified by simulating NEDC cycle conditions..