ISG并联混合动力轿车最优转矩分配策略

能量管理策略对混合动力汽车燃油经济性的改善具有关键作用。因为ISG混合动力轿车发动机转速不是受控变量,转矩成为能量管理策略惟一的控制变量,使其实质为转矩分配策略。考虑动力总成部件之间能量传递转换效率得到电机等效燃油消耗量,由此得到不同待选分配点动力总成等效燃油消耗率,以动力总成等效燃油消耗率最小化为原则优化转矩分配,使整车燃油经济性达到最优。通过离线计算,使转矩分配成为根据整车需求转矩、发动机转速和超级电容电压进行简单查表的过程,解决了计算量大的缺点,方便了实际应用和实时控制。建立整车和控制策略模型进行仿真计算,基于中国乘用车城区瞬态循环,与传统逻辑门限值分配策略相比,整车燃油经济性改善提高了5.2%。

Torque distribution for an integrated starter generator parallel hybrid electric car

Energy management strategy plays an important role in fuel economy improvement for hybrid electric vehicles.Because the internal combustion engine(ICE) speed is uncontrollable,the ICE torque becomes the only controllable factor for an integrated starter/generator parallel hybrid electric car. Therefore,energy management must consider how to employ a torque approach.A novel torque distribution strategy was used as the basis for minimizing the powertrain equivalent specific fuel consumption.The electric motor equivalent fuel consumption can be obtained by calculating the power conversion efficiency among the powertrain components.The disadvantage of long calculation times could be dealt with by employing off-line calculations.The optimal torque distribution becomes a simple process using the vehicle target torque,the ICE speed,and the ultracapacitor voltage.It is convenient for application and time controlling.Simulations were conducted with the vehicle and strategy models.Test results on a Chinese urban transient-state driving-cycle demonstrated that the fuel economy could be improved by 5.2% with this novel strategy.