| The traditional hydraulic excavator has some shortcomings,such as high fuel consumption and poor emission.With the development of power system energy saving technology,hybrid excavators can effectively improve fuel efficiency,but it still relies heavily on fossil fuels;pure electric excavator can achieve zero emission,no pollution,high efficiency and energy saving,but it cannot meet the requirements of excavator in endurance.Extended-range technology,as one of the research directions of new energy technology,can reduce fuel consumption to the greatest extent while meeting the endurance.Therefore,this paper mainly studies the power system and control strategy of extended-range electric excavator.Firstly,through the analysis of the traditional excavator structure and the characteristics of typical operating mode,a series power system was proposed in the paper,which took the battery and the engine as the power source and used the motor to drive the hydraulic pump as the system energy supply.The paper took the 8-ton excavator as the research object,selected the main components of the power system and matched the parameters.Secondly,according to the results of components selection and parameter matching,the power system model was built in AMESim.Through the analysis of the system structure and working principle of fuzzy control,the co-simulation control model was built in Simulink.The simulation analysis provided reference for the energy management strategy based on the deterministic rules which could be applied in actual engineering.Thirdly,the thermostat mode and thermostat & power following mode energy management strategy suitable for extended-range electric excavator were proposed by analyzing the working principle of energy management strategy based on determined rules.The power distribution of multiple power sources was analyzed by co-simulation.The simulation results show that the thermostat & power following mode can save about 5% fuel than the thermostat mode under the same operating mode,and the thermostat & power following mode fluctuation of battery charge and discharge power is better than the thermostat mode.Finally,the power system test platform of the extended-range electric excavator was designed and built.The performance of the power system,the power generation of the range extender and the two energy management strategies based on the deterministic rules were experimented.The experiments show the following results.The power system of the extended range electric excavator performs well.The efficiency of extender power conversion efficient area is about 90%.It is verified the simulation results that thermostat & power following mode has better battery charge and discharge power fluctuation than thermostat mode.Combined with the simulation results of better fuel economy of the thermostat & power following mode,it is confirmed that the thermostat & power following mode can be better applied to the extended-range electric excavator in engineering practice. |
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