Research On The Characteristics Of Power Coupling Mechanism And Mode Switching Coordinated Control Of Hybrid Elecric Vehicle

Hybrid Electric Vehicle(Hybrid Electric Vehicle,HEV)not only inherits the characteristics of strong power and high cruising mileage of traditional fuel vehicles,but also can reasonably combine and decompose different power based on efficient power coupling mechanism.Switch between working modes to achieve the effect of energy saving and emission reduction.The hybrid hybrid vehicle replaces the traditional gearbox with a planetary gear coupling mechanism called "E-CVT".The output power of the engine can be split or merged through the power coupling mechanism,and the power coupling system has gradually become a frontier direction of HEV research;the dynamic coordinated control during the HEV mode switching process will seriously affect the vehicle power and ride comfort.In this paper,a typical hybrid HEV is selected to carry out theoretical and applied research on the characteristics of its dynamic coupling mechanism and coordinated control.First of all,a typical dual-planetary hybrid system configuration is selected,and the dynamic characteristics,power splitting characteristics and transmission efficiency characteristics of the power coupling system are deeply analyzed,and the structural characteristic parameters are determined.According to the vehicle forward modeling method and experiment,The modeling method builds the dynamic model of key components,such as engine and motor,and establishes the dynamic model of the power coupling mechanism based on the lever model and the complete hybrid HEV switching model,which provides steadystate and dynamic coordination control for the subsequent energy management control and dynamic coordination control dynamic model.In order to explore the transient shock vibration and noise characteristics of dynamic coupling mechanism mode switching,a real vehicle road test is carried out,and the vibration acceleration and noise signals during mode switching including hybrid driving conditions and acceleration conditions are analyzed,and the vibration and noise conditions and transient state of the dynamic coupling system during mode switching under unsteady conditions are revealed.The law of switching characteristics lays the foundation for designing a reasonable coordinated control strategy.Second,the comprehensive transmission efficiency of the hybrid power system is deeply analyzed,and the optimal mode distribution module is designed with dynamic programming(DP),which transforms the HEV energy management problem into the torque optimization distribution problem of each power source aiming at the transmission efficiency of the whole vehicle,the predictive control strategy based on the optimal model of efficiency is designed,and the optimal control based on transmission efficiency is carried out,which improves the fuel economy of the vehicle and provides the basis for the coordinated control of HEV mode switching.Third,the influencing factors of the system stability during the switching process are analyzed,and a multivariable improved linear expansion state observer(MVILESO)is designed from the perspective of reducing the impact of vehicle mode switching and antiinterference coordinated control in view of its complex and changeable working modes.The engine torque disturbance and driving condition disturbance were estimated,the estimation accuracy and stability of MVILESO were simulated and analyzed,and the model predictive controller was designed in combination with the engine start-up mode switching rules,and the model predictive dynamic coordinated control based on disturbance observer was constructed.Strategy,the simulation analyzes the feasibility and effectiveness.Considering that the power source is affected by the time-varying response characteristics after the engine is started,combined with the influence of engine torque disturbance and output load side disturbance,it is necessary to redistribute the motor and engine torque,and a "basic motor torque compensation + Interference compensation torque redistribution" is designed.dynamic coordinated control strategy,through the accurate estimation of MVILESO and the torque redistribution algorithm of the interference compensation module,the vehicle achieves good speed tracking adaptability and switching process stability.Fourth,the three-dimensional solid model of the dynamic coupling system is established,the model is imported into ADAMS,and the rigid-flexible coupling dynamic model is established by comprehensively using the multi-body dynamics method and the finite element method,and the pure electric mode is gradually switched to the joint drive mode.Taking the power source angular velocity and characteristic gear meshing force of the power coupling system as the simulation observation targets,the influence law of the excitation of the double planetary gear mechanism on the mode switching shock vibration of the dynamic coupling mechanism is revealed.The corresponding observation objects are selected,and the multi-body dynamics simulation of the dynamic coupling system is carried out.The results show that the proposed dynamic coordinated control strategy has a good effect on improving the vibration and noise of the vehicle during the mode switching process.Finally,a D2P-based coordinated control strategy rapid control prototype and a hardwarein-the-loop experiment platform of NI real-time simulator are built,an energy management strategy based on transmission efficiency prediction,MPC based on MVILESO interference estimation,and interference compensation dynamic coordinated control strategy HIL are carried out.The experimental results verify the feasibility,practicability and superiority of the steady-state energy management strategy proposed in this paper and the "MPC+disturbance compensation" dynamic coordinated control strategy based on disturbance observation.