工程机械新型油电液混合驱动系统关键技术的基础研究

Duo to the energy crisis, the improvement on the efficiency of the hydraulic excavator is highly demanded.Though both the eletric hybrid power system and the hydraulic power sytem have played an important role in energy saving, they showed not only advantages but also disadvantages.Due to the large mass associated with the boom and the large inertia associated the swing,there are large of potential energy and kinetic energy which can be regenerated at the times of lowering and slewing stoppage of the excavator.Considering power density, energy density,economy of batteries, capacitors and hydraulic accumulators,a new structure of a oil-electrohydraulic drive system that combines the advantages of electric and hydraulic accumulator is analyzed. The power sytem can not only work in electric hyhrid mode, but it can also work in hyraulic hybrid mode.And the recycled energy can be converted into electric energy, mechanical energy and hydraulic energy. Then,parameter matching of this drive system is studied to optimize the hybrid system and the working pressure of hydraulic accumulator. Then, the energy management and distribution strategy on how to control engine, electric motor and hydraulic motor is developped.And the eletrohydraulic proportional technology for good operation performance and high recovery efficiency on the boom and the swing is presented. Hence, it can provide forceful theoretical and experimental references for further research on energy saving of power system in hydraulic excavators.

能源紧缺和环境恶化问题日趋严重的情况下，液压挖掘机的节能研究具有重要的现实意义。基于油电混合动力系统和液压混合动力系统的优缺点，考虑到电池、电容以及液压蓄能器在能量密度、功率密度以及成本等方面的特点，根据液压挖掘机动臂下放和上车回转制动时具有大量能量回收的特点，提出一种由发动机、蓄能器、液压马达以及电动机组成的新型油电液混合驱动系统，即大功率负载的波动由蓄能器-液压马达平衡，小功率负载的波动由电池-电动/发电机平衡，同时动臂势能和上车机构制动动能共用一套由动力系统关键元件组成的复合能量回收系统。针对新型驱动系统，提出以动力系统驱动性能、节能效果和经济性最佳综合效果为目标的参数匹配方法。研究适用于液压挖掘机剧变工况的基于负载主动预测的发动机速度控制、电动机和液压马达转矩控制的两级能量管理控制策略。研究既可高效回收能量，又可保证执行机构良好操作性能的动臂和上车机构的电液控制技术。

能源紧缺和环境恶化问题日趋严重的情况下，液压挖掘机的节能研究具有重要的现实意义。本项目是针对工程机械的高效节能进行的创新研究，研究了新型混合动力技术和能量回收技术在工程机械动力波动负载、直线运动执行器和旋转运动执行器的高效节能机理和方法。主要研究内容及创新：（1）深入研究了平衡油缸-蓄能器-电动/发电机组成的平衡单元特性以及电液平衡在机械臂驱动和再生系统的节能机理，提出可提高驱动和回收效率的平衡油缸平衡能力的主动控制方法；（2）针对转台提出了基于液压泵/马达平衡和电动/发电机主动控制的双动力驱动和再生系统及动力协调控制方法，保证转台加速和制动过程中的瞬时大功率和良好的运行特性，并研究降低在近零转速时的能量损耗方法。本项目将为工程机械提供一种新的高效节能、操控性好、适应面广的驱动方案。（3）考虑到电池、电容以及液压蓄能器在能量密度、功率密度以及成本等方面的特点，提出一种以液压蓄能器和蓄电池为复合能源的新型油电液混合驱动系统及控制方法，即剧变工况的波动由蓄能器-液压马达平衡，小功率负载的波动由电池-电动/发电机平衡。本项目将为工程机械提供一种新的高效节能、操控性好、适应面广的驱动方案。