Research On Energy Management Strategy Of Hybrid Electric Vehicle Based On Compound-structure Permanent-magnet Motor

New energy vehicle is at the forefront of the current global automotive industry transformation and automotive technology revolution.Among them,pure electric vehicle can achieve zero emission,no pollution,and high-efficiency energy-saving,it is the future direction of automotive development.However,due to the low battery power density and the incomplete auxiliary charging facilities,pure electric vehicles are still not widely available at present.Therefore,the consensus reached in the field of new energy vehicle is firstly taking the hybrid electric vehicle(HEV)route,this is due to the mature HEV technology,strong dynamic and endurance capabilities,high fuel economy,low cost and less demands for improving external facilities.The hybrid electric vehicle based on a compound-structure permanent-magnet motor(CSPM-HEV)belongs to series-parallel combined schedule,which can realize the functions of all hybrid topologies.The fuel saving performance is at the forefront among various types of HEV,and its control is flexible.There are many obvious advantages at the terms of power density,thermal efficiency,torque performance and energy transmission efficiency.This dissertation focuses on magnetic field decoupling for compound-structure permanent-magnet motor(CSPM),CSPM-HEV parameter matching and optimization and energy management strategies.The main work is shown below:First of all,the key to realize the energy management strategy of CSPM-HEV is the high dynamic performance torque control of CSPM.The decoupling of the magnetic field inside the motor is the basis of its torque control.In this paper,based on the equivalent magnetic circuit model and Ansoft finite element simulation model,the electromagnetic coupling mechanism inside CSPM is studied.The influence of different electromagnetic parameters on the air gap magnetic flux density in CSPM is analyzed,and a magnetic field decoupling design scheme is proposed.Secondly,the working principle,working mode and the law of energy flow under different working modes of CSPM-HEV are analyzed.Forward-backward simulation is used to model the hybrid vehicle,and the engine and its control system,CSPM and its control system,energy storage,and power transmission mechanisms are modeled.For nonlinear complex models such as engine,CSPM,and energy storage,their models are accurately described using theoretical modeling combined with experimental data modeling,which will not only ensure the accuracy of the control model but also increase the simulation speed.In the modeling process,the loss model of each powertrain is added to provide a simulation basis for the optimization of energy management strategy research.Next,two typical power transmission topologies of series-parallel combined schedule are compared and analyzed.A comparation on the work mode,power coupling,energy management strategy and fuel economy for Prius based on planetary gears and CSPM-HEV is completed.CSPM-HEV parameter matching optimization design and simulation analysis are carried out.Finally,based on the principle of fuzzy control,the membership function and control rules are designed,and the CSPM-HEV energy management system based on fuzzy logic control is established.The simulation and analysis are performed in different typical operating conditions.On this basis,with the vehicle efficiency as the optimization goal,an instantant optimization energy management strategy based on the principle of “minimum power loss” is formulated to reduce the fuel consumption of hybrid vehicles.Aiming at the problem of large amount of computation and poor real-time performance of the instantaneous optimization strategy,a real-time energy management strategy based on BP neural network is proposed,and the simulation experiment is conducted to analyze the control effect.