基于分级压差控制的电动挖掘机双变动力总成控制方法研究

工程机械电动化是节能减排的最为理想的驱动方式之一。传统工程机械采用的负载独立流量分配(LUDV)系统由于柴油机调速特性的限制,一般主要采用的是变排量定转速的变流量模式,多执行器同时工作时容易出现流量饱和。工程机械电动化后,电动机相对柴油机具有良好的调速特性。为了进一步避免流量饱和的现象,同时考虑到变量泵在低排量区间效率较低,提出一种基于分级压差控制的双变动力控制方法,对比实际负载压差与设定压差大小来提高操控性。分析不同目标流量阶段与负载实际压差之间的关系,实现全范围的流量匹配,控制变量泵的变排量工作区间处于效率较高区域,达到最大程度地避免流量饱和工况的发生;建立AMESim仿真模型进行仿真分析;搭建试验样机进行试验,验证了分级压差控制具有良好的流量跟随,解决传统挖掘机在低速定转速时流量饱和问题,高转速时节能性提高了19%以上。

Control Method of Double Variable Powertrain for Electric Excavator Based on Hierarchical Differential Pressure Control

Electrification of construction machinery is one of the most ideal driving methods for energy saving and emission reduction. The LUDV system used in traditional construction machinery is mainly used in the variable flow mode of variable displacement and fixed speed due to the limitation of the speed regulation characteristics of the diesel engine. When multiple actuators work at the same time, flow saturation is likely to occur. The motor has good speed regulation characteristics compared to the diesel engine. In order to further avoid the phenomenon of flow saturation, a dual variable power control method based on staged differential pressure control is proposed to explore the use of comparing the actual load pressure difference with the set pressure difference to improve maneuverability. The relationship between different target flow stages and the actual pressure difference of the load is analyzed to achieve a full range of flow matching. The variable displacement working range of the control variable pump is in a region of higher efficiency to avoid the occurrence of flow saturation. Simulation model is established in AMESim. Finally, a test prototype was built to test, and verified that the graded differential pressure control has a good flow follow-up, solves the problem of flow saturation at low speed and fixed speed of the traditional excavator, and improves energy saving by more than 19% at high speed.