Configuration Analysis Of Plug-in Hybrid Electric Vehicle With Single Planetary Gear

Planetary gear hybrid electric vehicle (HEV) combines the advantages of series andparallel hybrid vehicles, which can achieve the decoupling of the engine speed and torquefrom the wheel. According to the connection relationship between the power sources andoutput shaft, power-split hybrid electric vehicle can realize four different modes: input-split,output-split, compound-split and series modes. And according to the different combinationsof the four modes, planetary gear hybrid electric vehicle can be classified into two categories:single mode and dual mode. The input-split mode shows high efficiency at all vehicle speeds,so it is identified as the best system for single mode and also regarded as the suitable modefor dual mode at low vehicle speeds. The configuration characteristics and design of hybridelectric vehicle with single planetary gear are carried on through the research. The maincontents include:1. By researching the configuration characteristics and performances of planetary gearhybrid electric vehicle, the characteristics of planetary gear hybrid system can be listed: theengine power can be delivered to the output shaft through mechanical path and electric path,which can be able to achieve the decoupling of the engine speed and torque from the wheel.So, in the planetary gear hybrid system, the control of the engine is flexible. However, theenergy conversion in electric path affects the efficiency of the hybrid system directly. Theless power flows through the electric path, the higher the efficiency of the hybrid system is.The ratio is called mechanical point, when the power flowing though the electric path equalszero.2. The motor requirement of plug-in hybrid electric vehicle is relatively higher.Therefore, study the influence factors of highest speed and maximum torque of permanentmagnet synchronous motor.3. Dual-mode hybrid system can be realized by two or three planetary gears generally,and shows high efficiency in a wide speed range. But it’s hard to carry out the configurationscreening and parameter matching. However, GM Volt can achieve dual mode only by oneplanetary gear. In order to study the special configuration of GM Volt, the speed, torque andelectric power characteristics are discussed in comparison with the configuration of Prius Plug-in hybrid electric vehicle.4. Establish the lever model of the hybrid system with single planetary gear, andpropose the configuration screening conditions based on the highest speed and maximumtorque of magnet synchronous motor. Then select the appropriate hybrid systemconfiguration according to the screening conditions and design the CD mode and CS mode.5. According to the kinematic characteristics, analyze the distribution of the optimalengine operating point in different conditions and different modes. The optimal engineoperating point determines the efficiency of the hybrid system. Therefore, engine fuelconsumption (FC) is regarded as the evaluation criteria of the hybrid system.