Study On Control Strategy Of Parallel Hybrid Electric Loader

Loader is a kind of construction machinery which is widely used in infrastructureconstruction. With concern of environmental protection, energy saving and oil prices, theproblem that the high fuel consumption of loader is badly needed to solve.Based on the cooperative project of Jilin University and Guangxi LiuGong MachineryCo. Ltd.-" Research and Development of Parallel Hybrid Electric Loader ", combined withthe structure and parameters of the traditional wheel loader, this paper researched thecontrol strategy of parallel hybrid electric loader. The main research contents are asfollowing:First of all, the structure and working principle of the traditional loader were analyzed.Combined with the configuration characteristics of the parallel hybrid loader in this paper,the characteristic of hydraulic converter witch is the important component of transmissionsystem was studied, especially the input characteristics and output characteristics when thehydraulic converter worked with the power source. Based on the MATLAB programmingplatform, the basis was provided for the development of control strategy in the followingchapters by calculating the cooperating point of the hydraulic converter, the engine and themotor.Secondly, this paper proposed four kinds of control strategies to distribute the demandtorque between the engine and the motor, the engine optimal control strategy, the minimummotor power control strategy, the motor optimal control strategy and the instantaneousoptimal control strategy. The output torque range of the engine under different requiredtorque and different engine speed according to the kernel of control strategy was got withinthe MATLAB programming environment. This part of work was laid the foundation for thecontrol model.Thirdly, the model of the parallel hybrid electric loader was established on the AMESim simulation platform, and the four kinds of control strategies were built inMATLAB/SIUMULINK. Then the co-simulation of the model and control strategies wasexecuted.Finally, the simulation data were analyzed. Compared with ideal fuel consumption ofthe four control strategies, the reasons which led to the differences between the ideal andthe simulation were found out. Compared with the simulation fuel consumption anddynamic of traditional loader, the conclusions that whether the results of simulation werereached target were drawn. Then the improvement and focus of the work in future wereproposed.In summary, in this paper, the control strategy of parallel hybrid loader was studiedcombined its own characteristics. A theoretical calculation method on the inputcharacteristics and output characteristics of the common areas witch the hydraulicconverter and the two power sources worked together was proposed. And four options forthe demand torque distribution between the engine and the motor were established, andverified by simulation.The contents and thesis in this paper have guiding significance in the research on thecontrol strategy of hybrid electric loader.