混合动力挖掘机用镍氢电池SOC估算策略

State of charge estimation strategy of NiMH battery for hybrid hydraulic excavator

针对混合动力液压挖掘机上电池充放电工况复杂的问题,提出一种新的结合能量守恒模型和改进型电阻、电容等效电路(RC)模型的电池剩余电荷状态(SOC)综合估算方法,其中能量守恒模型增加了电池的反应热,改进型RC模型在RC模型基础上增加了迟滞效应电压,并运用sigma点卡尔曼滤波法对改进型RC模型的数据进行精确观测,通过调节权重系数将两者结合.针对镍氢(NiMH)池进行充放电实验,并采用能量守恒法、改进型RC模型法以及两者相结合的综合估算方法进行SOC估算的对比研究,结果表明:综合估算方法精度较高,适用混合动力液压挖掘机上电池的SOC估算.

Due to the complicate working conditions of battery in hybrid hydraulic excavate（HHE）,a new algorithm for battery state of charge（SOC）was proposed,which combined with two SOC model：one was based on conservation of energy to which the energy of battery reaction heat was added;and the other was based on an improved RC battery model for considering the hysteresis of battery,and the sigma point Kalman filter was applied to observe the improved RC model accurately.The combined algorithm was obtained by adjusting the weight factor of the two models.A charge and discharge experiment was done on NiMH battery.Three different SOC estimation methods,including SOC based on conservation of energy,SOC based on improved RC battery model,and SOC by the combined algorithm,were computed and compared.The result show that the combined algorithm has high accuracy and is suitable for HHE application.