| With the deepening of industrialization and the increasing demand for engineering construction,the sales volume of construction machinery is increasing year by year.Hydraulic excavators are widely used in various civil engineering due to their reliable operation,but the low efficiency of their transmission systems also brings adverse effects.A large amount of kinetic energy is lost in the form of heat energy in the excavator’s turning process,which not only causes the temperature rise of the hydraulic transmission system to be too high,but also seriously affects the service life of the whole machine.Therefore,this paper fully combines the characteristics of hydraulic energy storage elements and electrical energy storage elements,and proposes a composite electro-hydraulic energy recovery system based on the traditional swing system to recover swing braking energy and reduce system energy consumption.Aiming at this problem,the main contents of this paper are as follows:This paper firstly analyzes the energy consumption of excavators,and through a review of the current research status of energy-saving technologies for hydraulic excavators at home and abroad,it focuses on the development of energy recovery technology,and summarizes its shortcomings.provide a theoretical basis.Secondly,the structural characteristics and working condition characteristics of the excavator are analyzed,and the recoverable working condition stage is determined.A simulation model of a traditional slewing system is built to analyze the recyclability of slewing kinetic energy.The results show that the energy utilization rate of the system is only45.02%.Comprehensively compare various energy storage methods,put forward design goals for the hydraulic recovery module and electrical recovery module;and integrate each module,finally propose the hydraulic schematic diagram of the composite electro-hydraulic recovery system,and explain its mechanism.Thirdly,based on the traditional slewing system,the main components of the slewing part,hydraulic recovery module and electrical recovery module are matched and selected.First use AMEset to carry out secondary development of the necessary components in the simulation model,and then use AMESim to establish an electrical recovery model and an electro-hydraulic recovery model.The simulation action is set,and the results show that the electro-hydraulic recovery system can effectively reduce the overflow energy loss.The simulation can obtain that the flow utilization rate of the electro-hydraulic recovery system is about 67.45%,and the energy recovery rate is 59.61%,compared with the electrical recovery system.The system improved by 7.06% and 31.6% respectively.Considering the working conditions of the excavator,a small-volume high-pressure accumulator and a large-volume low-pressure accumulator are added to the basic electrical recovery module for two stages of full-load braking and no-load braking,respectively.The results show that the total recovery rate is 64.05%,which is 4.44% higher than that of the single accumulator electro-hydraulic type.Finally,in order to optimize the recovery rate,some key parameters of the hydraulic module and the electrical module are studied.The initial pressure and volume of the accumulator gas,the displacement of the recovery motor and the friction coefficient of the supercapacitor were batch processed,and the influence of each parameter on the energy saving effect was obtained.And according to the new recycling system,the basis for judging the rotation state is discussed,and a reasonable process control strategy is proposed.Analyze the MAP map of the motor,in order to improve the efficiency of the motor,the torque of the recovery motor and the generator is matched,so that the speed is maintained in the high-efficiency range of power generation of 1500-2000r/min.Using AMESim and Matlab/Simulink co-simulation control,the control results show that the motor efficiency of the system after torque matching is increased by 5.94%. |
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