Study On Powertrain Control System Of Pure Electric Vehicle

Pure electric vehicle uses motor as driving unit and power batteries as single energy sources, which can realize zero emissions. Comparing with fuel cell vehicle and hybrid vehicle, it has the most common key technologies, simpler structure and lower cost. It is much better for city cycle running. Therefore it is very important to do research and development for pure EV.Based on the national high technology research and development program"863", No. 2002AA501700, this research focus on the powertrain system of"QR pure electric vehicle"(QREV) and engage in systemic theory and experiment study. With detailed investigation on current domestic and international electric vehicle (EV) status, this paper studies QREV system function design, powertrain driving control, energy regeneration (ER) control and high voltage administration system. The control program, simulation platform and real road test were also described in this paper.The delaminating control mode was used to manage QREV multipoint controller and the mutual interface of every control unit were studied. The CAN communication network was designed to make the vehicle control platform. In order to extend pure EV running distance, this thesis focused on powertrain driving control technology research. The economy mode and power mode were designed and the related control strategy was studied, which contains start, drive, fail, idle and ER mode. With the energy regeneration principle deeply analyzing the cruising energy and braking energy regeneration was designed. Based on the regular braking system, B mode and C mode of ER method was developed, PI torque closed-loop control for brushless direct current motor (BLDCM) and PWM half bridge control method were designed, which provides a feasible method for ER engineering application. The auto disconnect module (ADM) was developed in this thesis, which can monitor insulation, pre-charge, grounding and high voltage inter-lock, total eight type of high voltage status. With high voltage experiment, ADM had very good dynamic respond. It can finish the high voltage connect within 135ms and disconnect in 13ms, which was 35% quicker than GB/T 18384.1―2001 request. Its performance can meet National and SAE safety criteria. The hardware in loop (HIL) simulation was built for the powertrain control module (PTCM) debugging in this paper. The vehicle model, BLDC model and battery model were built in PC. The Labview graphic language, C language and multithreading programming skill were used to make the models and graphic monitoring interface transferring, which ensure the HIL system real time respond.The research was applied on national high technology research and development program"863.QR pure electric vehicle", No. 2002AA501700. The QREV has good driving capability and can acceleate to 50km within 8.4s. The energy feedback can reach 9% with ER technology. The vehicle can run more than 300km, which is 50% higher than national science and technology department request. The vehicle performance met the inspection of North China vehicle quality certificated research institute and National science and technology department's validation.