液压挖掘机混合动力系统参数匹配与控制策略研究

发布时间：2018-09-15 05:45

【摘要】：液压挖掘机在现代化建设中发挥着重大的作用，同时它也具有能耗高、排放性能差的特点，随着环境恶化的日趋严重和国际油价的逐步攀升，挖掘机的使用成本也不断地提高。因此，提高液压挖掘机的工作效率，使之更加节能就显得非常重要。对液压挖掘机节能性的研究应把重点放在动力系统，因为动力系统的好坏对挖掘机的油耗特性和排放特性都有重要的影响。为此，文章展开混合动力系统在液压挖掘机上应用的研究，以开发出效率更高、更节能的挖掘机动力系统。论文从挖掘机的循环工况入手，对混合动力动力系统的构型、元件的参数匹配和控制策略进行研究。论文在对国内外混合动力挖掘机研究的基础上，，根据液压挖掘机的循环工况特点，提出了并联式混合动力系统的方案即：电机协助发动机并联驱动负载；回转电机驱动回转机构，同时回收制动过程中的能量并将其存储于能量储存装置中。在动力系统的基本构型确定之后，根据动力系统的工作特点进一步讨论并确定了采用超级电容作为能量存储装置，ISG电机作为助力电机，电机作为回转机构的驱动兼能量回收部件。在AMESim平台上建立了动力系统的仿真模型，并确定了常用的重载挖掘工况下的负载功率作为仿真模型的负载输入，对并联式混合动力系统的工作性能和油耗性能进行了仿真。为进一步优化混合动力系统的油耗特性，文章对所设计动力总成中发动机、ISG电机、回转电机和超级电容的参数进行了匹配计算。将经过匹配的动力系统元件的参数带入到AMESim仿真模型中进行仿真，验证了经过参数匹配后发动机、ISG助力电机和回转电机工作点稳定，且能最大程度的工作在各自的高效区，参数的合理匹配提高了整个动力系统的工作效率，减少了整机油耗量。结合并联式动力系统的特点，提出了发动机工作点控制、最小助力和电量平衡自适应控制策略。文中介绍了三种控制策略的控制原理及优缺点：发动机工作点控制策略实现简单，发动机工作点稳定、效率高，但助力电机的工作点切换比较频繁；最小助力控制策略中发动机和ISG助力电机的工作点都比较稳定，且能够根据超级电容SOC实时的调整充电和助力扭矩；电量平衡自适应控制策略不仅能够调节电机的工作状态还可以根据负载实时调整ISG电机的助力和充电扭矩。将这些控制思想写入到Matlab/simulink程序中，用Matlab/simulink与AMESim联合仿真的方式对三种种控制策略进行了仿真分析。仿真结果表明，在并联式混合动力系统中采用上述三种控制策略后，整机的油耗特性都有所改善，其中采用最小助力控制策略时，系统的油耗特性最优。但鉴于仿真系统不能完全模拟混合动力系统的工作情况，对采用最小助理控制策略的并联式混合动力挖掘机样机进行了整机挖掘实验，通过对样机发动机、ISG助力电机、超级电容和回转电机工作状态的分析，验证了动力系统元件匹配的合理性、控制策略和AMESim仿真平台的正确性；对整机挖掘循环时间的记录证实了样机生产效率有所提高；对发动机油耗的监测证实了整机的能耗有所降低。最后论文提出混合动力挖掘机中一些值得进一步研究的新问题，如工作模式控制策略的开发、超级电容能量管理和整机热管理等。
[Abstract]:Hydraulic excavator plays an important role in the modernization construction, and it also has the characteristics of high energy consumption and poor emission performance. With the worsening of the environment and the gradual rise of international oil prices, the use cost of hydraulic excavator is constantly increasing. Therefore, it is very important to improve the working efficiency of hydraulic excavator and make it more energy-saving. It's important.
The research on energy saving of hydraulic excavator should focus on the power system, because the quality of power system has an important impact on the fuel consumption and emission characteristics of excavator. Starting from the excavator's cyclic working condition, the configuration of hybrid power system, parameter matching of components and control strategy are studied.
Based on the research of the domestic and foreign hybrid excavators and according to the characteristics of the hydraulic excavators'cyclic working conditions, this paper puts forward a parallel hybrid power system scheme, that is, the motor assists the engine to drive the load in parallel, the rotary motor drives the rotary mechanism, and at the same time reclaims the energy in the braking process and stores it in the energy storage device. After the basic configuration of the power system is determined, the simulation model of the power system is established on the AMESim platform, and the simulation results are confirmed. The load power of the commonly used heavy load excavation condition is selected as the load input of the simulation model. The performance and fuel consumption of the parallel hybrid power system are simulated.
In order to further optimize the fuel consumption characteristics of the hybrid power system, the parameters of the engine, ISG motor, rotary motor and supercapacitor in the powertrain are matched and calculated. The parameters of the matched components of the power system are brought into the AMESim simulation model for simulation, which verifies that the engine is aided by ISG after parameter matching. The working points of the force motor and the rotary motor are stable, and they can work in their respective high efficiency areas to the greatest extent. The reasonable matching of the parameters improves the working efficiency of the whole power system and reduces the oil consumption of the whole machine.
Combining with the characteristics of parallel power system, the adaptive control strategies of engine operating point control, minimum boost and power balance are proposed. The control principles and advantages and disadvantages of the three control strategies are introduced in this paper. The control strategy of engine operating point is simple, the engine operating point is stable and the efficiency is high, but the working point switching ratio of the boost motor is high. It can adjust the charging and torque in real time according to the supercapacitor SOC. The power balance adaptive control strategy can not only adjust the working state of the motor, but also adjust the power and charging torque of the ISG motor in real time according to the load. These control ideas are written into the program of MATLAB/simulink, and the three control strategies are simulated and analyzed by means of the joint simulation of MATLAB/simulink and AMESim. The simulation results show that the fuel consumption characteristics of the whole engine are improved after the above three control strategies are adopted in the parallel hybrid power system, in which the minimum aid is adopted. The fuel consumption characteristics of the system are optimal when the force control strategy is applied.
In view of the fact that the simulation system can not completely simulate the working conditions of the hybrid power system, the whole excavation experiment of the parallel hybrid excavator prototype with the minimum assistant control strategy is carried out. The matching of the power system components is verified by analyzing the working conditions of the prototype engine, ISG assistant motor, supercapacitor and rotary motor. The rationality, the control strategy and the correctness of the AMESI simulation platform, the record of the excavation cycle time confirm that the prototype production efficiency has been improved, and the monitoring of the engine fuel consumption confirms that the energy consumption of the whole machine has been reduced. The development of control strategy, super capacitor energy management and whole machine thermal management.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU621

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