Optimization Design And Characteristic Study On Electro-mechanical Continuously Variable Transmission

Currently,faced with the circumstance of energy shortage and increasing requirements of environmental protection,most traditional auto industries have suffered huge hit.So the exploitation and utilization of new energy has become a major trend in the coming period of time.And electric vehicle undoubtedly will attract more attention with its superior performances in energy-saving and environmental protection.As the bridge of matching power source and vehicle,transmission is a very important part in the vehicle drive system.For its reasonable match design can effectively enhance dynamic performance and economic performance of the car,it can also be used in electric vehicles to reduce the motor performance requirements of driving conditions.In terms of the dynamic performance matching,relative to the traditional stepped transmission,the continuously variable transmission has a better and more adaptable effect.In this passage,a kind of Electro-mechanical Continuously Variable Transmission has been researched.It uses double motor as the power source,and the main motor M1 mainly provides the driving force,the speed regulating motor M2 plays the role of regulating the output speed.It has the advantages of large transmission ratio,wide speed range,light weight,high system flexibility and easy control.The major research contents of this paper are as follows:(1)A kind of CVT based on the two-degree differential planetary gear train has been put forward and researched.Analyzing its characteristic in various schemes,such as continuously variable characteristic,power flow characteristic and efficiency characteristic.Based on one-stage planet row,Analyzing the characteristics of two-stage planet row and choose the suited scheme.(2)Introduce the basic performance of permanent magnet synchronous motor,analyzing force condition in driving and matching the main motor M1.Choose the transmission scheme according to design requirement and calculating main parameters.Build mathematical model using Particle Swarm Optimization and optimize parameters of the transmission scheme.Analyzing its characteristic and matching the speed-regulation motor M2.(3)Design the control framework of continuously variable transmission system according to different driving demand to match the dynamic efficiency and economical efficiency.Using fuzzy logic control to provide compensating torque in the speed-up working condition.Design the speed-steady strategy to deal with load-changing condition and adjust the speed back in the allowable range.Build dynamic model with CATIA and ADAMS according to the designed model.Do joint simulation with matlab/simulink and analyzing its characteristic in the control strategy.(4)Build testbed to test the designed electro-mechanical continuously variable transmission system.Applied driving force and load to the system according to theoretical arithmetic.Acquired data when the system run steadily and analyzing its characteristic.Testify that the transmission scheme has steady continuously variable characteristic and high efficiency.