Parameter Match Theory Of EVT Hybrid System And Its Laboratory Prototype

Hybrid technology can reduce the fuel exhaustion and emission by improvingthe efficiency of the driventrain system and it is an proper solution for the energyand environment problems at the present stage. The key technology of hybrid driveis to integrate the power from engine and energy storage package. The Four PortsElectro-mechnanical Energy Converter (FPEMC), which is also called ElectricalVariable Transmission (EVT), comprises an inner machine with double rotors andan outer machine. With double mechanical ports and double electrical ports,FPEMC is favored as an integrated hybrid solution because it can achieve thefunction of CVT and Hybrid simultaneously.The optimal parameter match and design of FPEMC hybrid vehicle are studyedin the thesis. The degree of hybridization (DOH) definition of EVT based hybridvehicle is derived, as well as the DOH match method. It is concluded that EVT isfavored in the full-hybrid application, and the optimal parameter matching methodof EVT based hybrid vehicle is proposed.There exist the problems of magnetic field coupling, cooling system of innermachine and control strategy for FPEMC, which can be partly solved in the terms ofthe whole vehicle, combining the powertrain design and EVT design. At present, themagnetic field coupling of EVT can be avoided by adding an isolated ring,seperating the magnetic flux physically. In order to solve the thermal problem of theinner machine, the drivetrain parameters are designed with the goal of minimizingthe power of inner machine, simplifying the requirement of the colling system,which is the root solution.Diffident operation modes of EVT and their internal relationship are analyzedcompared to Parallel Hybrid System. In order to build the control program, varies ofoperation modes are separated into2categories depending on the status of ICE.Because the speed of ICE can be completely decoupled from the wheel, ICE can beoperated on the efficiency optimal line, tracking the required power of vehicle. EVTis torque controlled, tracking the torque demands of the driver. Both power andtorque tracking can be realized at the same time. ICE’s flexible switching on/off canoptimize its operation region, improving the efficiency of the vehicle and fueleconomy, and minimizing the emmision. To avoid the shotage of EM1’s lowefficiency when works at low speed, a modified control strategy of EVT vehiceles isproposed based on the mature parallel hybrid control strategy, improving the controlstrategy of EVT.To supply the experimental data for the future design and control of EVT, and provide practical parts for the hybrid control strategy, an integrated EVT prototypeis designed and manufactured based on the requirement of EVT hybrid system. Theexperiment results show that both the inner and outer machine can meet the designindex basically, which guarantee the application on hybrid system.