Development Of Powertrain System For Extended-Range Electric Vehicle And Research On Energy Optimization

Energy cricis would require new energy resources for automotive industry.Electric energy is considered by automotive industry as a kind of clean,extensive-soures energy. But currently, with the restraint on energy density anddurability, pure electric vehicle could hardly achieve large scale manufacture.Conventional hybrid technology could optimize the working point of engine andreach higher efficiency, but it can hardly reduce the dependence on crude oilsignificantly. As a kind of configuration between pure electric vehicle andconventional hybrid one, extended-range electric vehicle (E-REV) couldguarantee the vehicle driving range and protect the battery from deepdischarging. In another aspect, E-REV coulde use more electric energy tosubstitute fossil energy. This thesis developed the powertrain system for anextended-range electric bus, and did some research on the energy management.This thesis selected parts for the powertrain system of extended-rangeelectric bus based on dynamic performance and economy. The motor parametersare determined based on power requirements. From the motor parameters,battery size and rate parameters of auxiliary power unit (APU) are selectedconsequently. Other parameters of battery, engine, and generator are selectedbased on economy.The control system is the core of E-REV. This thesis designed a distributedcontrol system for the powertrain based on TTCAN network. The control systemcould be divided into two level, vehicle level and APU level, and the APUsystem is modularized. The software of vehicle control is developed byautomatic code generation technology based on MATLAB/Simulink. Individualmodules such as parameter input/output, switching of vehicle mode, drivingexplanation, and diagnosis are built in Simulink and the code isgenerated/downloaded to the microcontroller. Both the hardware and softwareof APU controller are developed. The software function includes APU start/stop,torque co-operation of engine and generator, and diagnosis.This thesis also has built the model for powertrain system based on the busdeveloped before. Several strategies of energy management are simulated in themodel. All the simulations are done based on Chinese city bus cycle consideredone day distance. Every result of simulation is evaluated and analyzed based on theory. A new regenerative braking strategy is raised and evaluated. Accordingto the experiement, this new strategy would reduce5.3%of the total electricconsumption. The optimized energy management strategy is raised in order toreduce the total fuel consumption specific to the configuration developed above.From the road test, the fuel consumption in hybrid mode is below26L/(100km).