Design And Performance Analysis On Driving System Of Series Hybrid Electric Tractor

With the improvement of the level for agricultural mechanization,the ownership of the tractor is increasing year by year.As the traditional tractor may excessively consume non renewable energy resources and exhaust pollution,which have become the stumbling block of sustainable development.Thus many countries have started to develop green environment-friendly hybrid electric tractors.At present,abroad has developed series hybrid electric tractors,while China is still in the research,the direct driving tractor with hub motor is nearly out of studies.In view of the above situation,this paper studied the series hybrid tractor,and designed a driving system with hub motor based on the research status at home and abroad.In this paper,the methods of research include theoretical analysis,simulation and bench test.The main work and conclusions are as follows:1.Study on parameter design and matching method of series hybrid electric tractor driving system.By comparing the existing driving scheme of series hybrid electric tractor,used direct driving system with hub motor,namely each rear wheel of tractor is driven by hub motor independently.At the same time,design and matching the parameters of driving components and tractor according to the characteristics of ploughing,rotary tillage and transportation conditions.Then design the tractor's main parameters and choose the matching plough machine and rotary cultivator.2.Design and kinematics simulation of power distribution device.According to tractor rotary tillage requirements,designed a power distribution device.The device was divided into three grades considered the driving mode of series hybrid electric tractor.The transmission structure of the device was designed,including gear modules,tooth number,tooth width coefficient,transmission ratio,structure and diameters of shafts and other supporting and sealing parts.Meanwhile,completed the optimization of gear parameters with enough strength and no interference in order to reduce the volume of this device.The calculation and simulation results show that the shafts in that device can satisfy the requirements of rotary tillage condition,and the device could output the standard rotary speed of PTO,which is 540r/min and 1000r/min.3.Theoretical analysis and simulation of' the performance of series hybrid electric tractor driving system.This paper mentioned the performance of traction,power take off,economic as the evaluation index of hybrid tractor.Then the calculation formula of traction force,maximum torque of power take oft shaft,and energy consumption were given.Used the software SimulationX to set up the simulation model of series hybrid tractor,imported parameters of driving components and ploughing condition.The simulation results show the rolling resistance of series hybrid tractor is 1781N,the traction force is 7405.9N,the operating distance in one hour under the speed of 6,7,8km/h are 5989m,6986m,7913m;at the same time,the decreases of battery's SOC are 47.97%,60.66%and 72.37%;the consumption of electric energy are 8.654kW h,10.84kW·h,12.89k W·h;the consumption of diesel is 1.368L which can be equivalent into 11.96 kW h.So the total energy consumption are 20.614 kW h,22.8 kW·h,24.85 kW h4.Research on test bench of series hybrid electric tractor.According to the test requirements,test bench was be divided into power system test module,driver simulation module,load simulation module,data acquisition and control module.Completed the calibration of voltage sensors,current sensors,torque sensors,and performance tests of driving components.Developed a measurement and control platform based on software Lab VIEW in PC and data acquisition card NI USB-6343,which implemented signal acquisition and controlling of overall system.The tests results show this test bench could collect all data of sensors and putout the controlling signals of motor speed and loads,while there exists zero drift,which should be zeroed before tests started.5.Performance tests of series hybrid electric tractor.These tests analyzed the power take off performance and traction,economy performance under variable driving modes.The tests results show this tractor could output 10.16-33.74kW for power take off shaft according to diverse tilling depth.When the tractor is under electric driving two rear wheel mode,the driving system could provide the maximum driving force is about 8775.1N,the traction efficiency is between 0.82-0.86,if the hub motor could working 1 hour at rated power,the consumption of electric energy is 18.68kW·h;when the tractor is under series hybrid driving two rear wheel mode,the driving system could provide the maximum driving force is about 8115.2N,the traction efficiency is between 0.7-0.85,if the hub motor could working 1 hour at rated power,the consumption of diesel is 4.49kg,the equivalent energy consumption is 53.88kW·h;when the tractor is under electric driving one rear wheel and series hybrid driving one rear wheel mode,the driving system could provide the maximum driving force is about 8445.4N,the traction efficiency is between 0.81-0.88,if the hub motor could working 1 hour at rated power,the consumption of electric energy is 9kW·h,the consumption of diesel is 2.82kg,which the equivalent energy consumption is 33.84kW·h,thus the total consumption is 42.84kW·h.