THS-III纯电动模式下的发动机转速控制

Engine Speed Control of THS-Ⅲ Hybrid System in Pure Electric Drive Mode

利用杠杆法对THS-III混合动力系统的纯电动加速过程进行了动态分析,通过仿真比较了不同驱动需求转矩、发动机静态阻力转矩和扭转减振器阻尼对发动机转速波动的影响。结果表明,纯电动模式下若仅对驱动电机实施转矩控制,可能会直接导致发动机被起动并产生转速波动,从而严重影响车辆行驶的平稳性。为此,设计了纯电动模式发动机转速补偿控制策略,并合理地选择控制器采样时间。经Matlab平台仿真验证,所采取的措施明显降低了发动机转速波动,在满足驾驶员转矩需求的情况下,改善了车辆行驶的平稳性。

A dynamic analysis is conducted on the acceleration process of Toyota’s THS-Ⅲ hybrid system in its pure electric drive mode by using lever analogy technique. The effects of required drive torque, the static resist-ance torque of engine and the damping of torsional vibration damper on the fluctuations of engine speed are compara-tively analyzed by simulation. The results show that in pure electric drive mode, the sole torque control over driving motor may lead to engine being started unintentionally with speed fluctuation, severely affecting the ride comfort of vehicle. Accordingly, a compensation control strategy for engine speed in pure electric drive mode is devised with the sampling time of controller properly chosen. The final simulation with Matlab verifies that the measures taken ap-parently reduce the fluctuation of engine speed and improve the ride comfort of vehicle while meeting the torque re-quirement of driver.