Configuration And Control Strategy Study Of Plug-in Hybrid Vehicle With Single Planetary Gear

Under the background of global energy increasingly shortageand the worsening ecological environment,in order to reduce the increasing greenhouse gas emissions,fuel consumption and energy crisis,the research of automobile energy conservation and emission reduction technology is widely concerned.The power-split hybrid electric vehicles(HEV)based on the planetary gear can effectively improve the fuel consumption and emission of the automobile,and is a research hotspot in the new energy automobile market.This dissertation is supported by the national key research project "plug-in HEV powertrains and dynamic control method research",and studied the following research about power-split HEVs based on one planetarygear.(1)Using the leverage method to analyze all possible configuration schemes of single planetary gear with one engine and two motors,which are classified according to the combination of power source.After eliminating the obviously invalid configuration scheme,there are 12 feasible power-split configuration schemes,in which there are 6 input-split configuration schemes and 6 output-split configuration schemes.Based on the detailed research of input-split configuration schemes and output-split configuration schemes,the paper sifts 1 output-split configuration scheme and 1 input-split configuration scheme from 12 feasible configuration schemes on the basis of whether there is a mechanical point,the motors speed and torque constraints,and power split ration.(2)In order to compare the performance of two selected configuration schemes,two vehicle powertrains based on two selected configuration schemes is constructed,the characteristics of which are analyzed and the mathematical models of which are established.In this paper,a design method of the parameters of power split powertrains is proposed for the multi-degree-of-freedom characteristics of single-planetary power-split powertrains.The parameter design of main components,such as engine,planetary row,main reducer,motor and battery,is successively designed,and the models of which are established in the MATLAB software.(3)According to the work characteristics and parameter matching results of two powertrains,a rule-based control strategy was established for the two powertrains.In order to solve the distribution problem among three power sources,the calculation method of equivalent energy consumption is studied.With the minimum energy consumption as the target,the equivalent consumption minimum strategy(ECMS)is adopted to optimize the speed and torque distribution among three power sources.The optimization results show that the two powertrains can adjust the speed torque of the two motors to realize the decoupling of the engine and the wheel in speed and torque.(4)Finally,the two powertrains are simulated under the four driving cycles of NEDC,UDDS,HWFET and US06 respectively.The results show that the equivalent fuel consumption of the output powertrain under four working conditions is less than the input powertrain.Under the driving cycle of UDDS with low average speed,the energy consumption difference of the two powertrains is 7.6%.Under the HWFET driving cycle with high average speed,the energy consumption difference of the two powertrains is 12.6%,which verifies that the input-split powertrain configuration scheme has the power cycle in the high speed condition and reduces the efficiency of the power system.The above research provides theoretical support for the configuration scheme design and parameter matching of single planetary with single engine and dual motor hybrid vehicle.It is of great significance to design and optimize the control strategy of power-split HEVs based on single planetary gear.