Research On Efficiency Optimization Of Electric Bus Motor System Based On Working Condition Large Data

Developing electric vehicles is an important way to solve the problem about the frequent haze weather in city and high dependence on oil at present.Electric buses have been highly regarded by governments all over the world and widely used,because they are mainly used in public transportation and have remarkable energy-saving and emission reduction effects,however The short driving range and high energy consumption of electric bus have become the bottleneck problem in the electric bus industry.In this report,the motor system as the research object,have been fitted into the electric vehicle and motor conditions,based on the actual conditions of large data;and the energy management strategy and the motor is optimized through analyzing the actual conditions of energy dissipation and efficiency,to enhance the overall efficiency as the goal.The main research results are as follows:The actual operation data of the electric bus in the market are analyzed statistically,which are applied to large data mining.The motor working conditions have been fitted,and the working condition database for the forward development of the motor have been established.Based on typical working condition of the motor system,optimize the control algorithm of the motor controller.Adopt the variable frequency algorithm to improve the efficiency of the area below 50Hz;develop over-modulation optimization algorithm to improve the efficiency of the weak magnetic field,and improve the maximum efficiency of the integrated motor controller from 97% to 97.3%.Based on typical working conditions of the motor system,optimize high efficiency area of the motor;increase the overlapping ratio between high efficiency area of the motor system and the typical working conditions,reduce the power consumption.The use of low loss soft magnetic materials,stator chute,and air gap harmonic wave optimization technology improves motor efficiency,and the Max.Efficiency is improved from 95.5% to 96.3%.Based on typical working conditions,do bench test about motor efficiency and energy dissipation.The power analyzer is used to observe and record test simulation process.The results show that the efficiency is improved from 82.36% to 83.53% under driving working condition and from 66.58% to 71.41% under feedback working condition via the efficiency enhancement of the motor system.The optimization effect is obvious.Based on the data of pure electric bus operating conditions,create optimization proposals,which include different control methods such as multi-objective optimization,global optimization and space vector control to optimize overall vehicle,motor and electrical accessories.After optimization,the A/C on 8m pure electric bus at full load under urban conditions is off,and the power consumption is reduced from 0.478 kWh / km to 0.453 kWh / km with the reduction ratio of 5%.Under work condition of 40 km / h constant speed driving range,and half-load,also with A/C off and the power consumption is reduced from 0.388 kWh / km to 0.349 kWh / km with a reduction ratio of 10%.