The Study On Energy Recovery And The Experiments For Electric Forklift System

In recent years,with the green energy,high energy efficiency,sustainable concept popular among people,electric forklifts are widely used in airports,warehouses,food,microelectronics and other places because of its easy operation,noise,pollution-free advantages.In the rapid development of the logistics industry,the demand for electric forklifts increased rapidly.When the electric forklift stacking the goods,the lifting system frequently reciprocates,and the potential energy will continuously be converted into heat,which being dissipated in the hydraulic system and causing the hydraulic system temperature rise.Then it will reduce the use and the life of hydraulic components performance and other issues.So the electric forklift energy-saving research has great market value and practical social benefits,which has gradually become the current forklift industrial technology research hotspot.In this paper,based on the above problems and combined with the basic research projects of central universities,a research for electric forklift lifting system energy conservation was did,and the main contents are as follows:(1)This paper analyzes the current situation of electric forklift and its energy saving technology both at home and abroad,and puts forward a lifting mechanism potential energy recovery program based on asynchronous motor(generator)-pump(hydraulic motor)-battery system and the energy consumption distribution test data of 2.5 T electric forklift.And on this basis,the research was did for system theory and technology applied.(2)This paper analyzes the energy saving principle of frequency conversion speed regulation technology in forklift electro-hydraulic system.Based on the load torque characteristics of electric forklift and the characteristics of hydraulic system,direct torque control technology can be applied in forklift electro-hydraulic control system and the energy conservation principle.(3)The innovation of this paper lies in the use of asynchronous motor,which can work as the generator.The battery can be connected to the controller output,in order to achieve the conversion of hydraulic energy to electric energy and battery charging.Combined with the characteristics of electric forklift tonnage and energy saving technology program,we could make parameter matching and design calculation to provide theoretical basis for the selection of components,and to build the test bed.(4)The experiment is carried out by using the Altai PCI9602 data acquisition system to verify the feasibility of the scheme and to study the efficiency of energy recovery under different load and speed.The test results show that when the motor speed is 1200 r/min,the increasing potential energy is 1286.82 J for every 138 kg of the load,and the potential energy recovery efficiency is as high as 79.29%.The energy saving technology and realization method of the battery as the energy storage element were discussed,and the optimal working condition that the speed of the motor is 1200 r/min of the potential energy recovery efficiency was also studied by experiment.This scheme provides an effective reference for the electric energy saving technology of electric forklift,and it has a certain practical value.