混合动力挖掘机动臂能量回收单元及系统研究

发布时间：2018-06-11 14:52

本文选题：混合动力 + 能量回收　；参考：《浙江大学》2013年博士论文

【摘要】：动臂能量回收是进一步降低混合动力挖掘机燃油消耗和废气排放的有效途径,对改善挖掘机高能耗、高排放的现状具有重要意义,相关研究还可为其它类型工程机械的能量回收提供一定的参考和借鉴。对于混合动力挖掘机,能量回收的引入改变了动臂作业的控制模式,如何同时保证良好的节能性和操作性是当前制约该技术实际应用的瓶颈。为了解决该难题,论文提出了一种新型的动臂能量回收系统方案及工作原理：系统方案采用液压马达-发电机能量回收单元加串流节流阀结构,在工作原理上引入压力补偿的思想,即控制发电机使其电磁转矩自动适应负载压力,一方面保证节流阀前后压差恒定且较小,进而调节其阀口开度可有效控制动臂运动,另一方面由液压马达-发电机单元对能量进行回收再利用；根据矢量控制发电机转速信息和节流阀流量-压差映射关系对节流阀压差进行估计,并应用于基于压差控制的动臂能量回收系统,实现了可降低成本及复杂性的无传感器控制方案。此外,论文对影响能量回收系统性能的关键部件——液压马达-发电机单元进行了深入研究：针对能量回收发电机尺寸约束下保持高效率及低转矩脉动的性能要求,提出了通过参数化电磁设计模型和有限元分析对其定、转子结构参数进行分步协同优化的设计方法,兼顾了设计效率和准确性；分别在电气和机械层面探讨了液压马达-发电机单元的控制,设计了反馈和前馈相结合的电流控制器和带扰动补偿的转速控制器,保证其在转矩和转速模式下均具有较为理想的动态性能。论文提出的一整套动臂能量回收系统设计和控制方法,可同时实现良好的动臂操作性和能量的高效回收,有力地推动了动臂能量回收系统在混合动力挖掘机的实际应用。论文各章内容分述如下：第一章阐述了当前能源紧缺、环境恶化背景下开展挖掘机动臂能量回收研究的重要意义；介绍了工程机械动臂能量回收的研究现状,分析了几种能量回收方案的特点及存在的问题；针对适用于混合动力挖掘机的电气式能量回收系统,介绍了液压马达-发电机能量回收单元的元件选型,并综述了永磁发电机的设计和控制方法；最后提出了课题的主要研究内容。第二章从总体上对混合动力挖掘机动臂能量回收系统进行了研究。分析了系统作业工况特点,归纳了系统主要性能评价指标,包括节能性和操作性。提出了液压马达-发电机能量回收单元加串联节流阀的新型系统结构方案。建立了系统主要元器件的数学模型,分析了能量传递流中各个转换环节的损耗,探讨了系统的参数设计问题,为进一步开展元件级的研究打下了基础。第三章对能量回收发电机的设计及优化方法展开了研究。针对能量回收发电机尺寸约束下保持高效率及低转矩脉动的性能要求,提出了定、转子结构参数分步优化的设计方法：先以结构尺寸受限下的损耗最低为目标,基于参数化模型和粒子群算法获得最优的定子结构参数和磁感应强度分布；再以气隙磁感应强度的波形畸变最小为目标,利用有限元方法优化永磁体结构参数,并保证磁感应强度的实际分布与定子优化结果一致。分别对电枢反应、永磁体最大去磁、间歇性作业下的温升进行了计算和校核。研制了能量回收发电机样机并进行了性能和参数测试,测试结果验证了设计及优化方法的有效性。第四章研究了液压马达-发电机能量回收单元的控制。在电气层面研究了永磁发电机的电流控制,为了降低反电动势的影响,设计了带前馈补偿的比例-积分电流控制器；在机械层面研究了液压马达-发电机单元的转速控制,针对液压马达入口压力变化剧烈的特点,引入了扰动补偿以提高系统的抗干扰能力。建立了相应的仿真模型,对设计的控制方法进行了仿真研究。搭建了基于模拟加载的试验台架并进行了试验研究,试验结果表明,液压马达-发电机单元在转矩和转速模式均具有良好的控制性能,为进一步研究动臂能量回收系统的控制方法提供了支撑。第五章研究了对动臂操作性具有主导性影响的能量回收系统控制方法。结合系统结构和特点提出了三种控制方法：直接转速控制,通过控制液压马达-发电机单元的转速调节动臂液压缸速度,节流阀基本处于全开状态；负载压力控制,通过节流阀调节动臂液压缸速度,根据负载压力反馈确定单元的目标转矩；节流阀压差控制,也通过节流阀调速,但根据节流阀压差闭环控制确定单元的目标转矩。推导了系统在各种方法下的传递函数,根据对动态性能的分析和比较,论证了节流阀压差控制具有最优的频响和阻尼特性。搭建了混合动力挖掘机动臂能量回收试验台架并进行了试验研究,试验结果验证了理论分析。第六章进一步深入研究了基于压差控制方法的能量回收系统。通过与定差减压型压力补偿器的类比,将能量回收的原理由动臂下放过程扩展到包括提升和下放的全过程,并分析了两种工况的可回收能量。为了避免使用额外的压差传感器以降低系统成本及复杂性,提出了利用矢量控制发电机的转速反馈信息和节流阀的流量-压差映射关系进行压差估计的无传感器控制方法,分别从稳态和动态上论证了有／无传感器控制的等效性。最后从操作性和节能性两方面进行了大量试验研究,试验结果表明,提出的动臂能量回收系统及控制方法在典型作业过程中具有良好的动态性能,能够适应各种动作需求；实际回收能量与理论分析一致,总回收效率在40%-50%之间,且具有一定改善空间。第七章总结了论文的主要研究工作和创新点,并对课题后续的研究方向进行了展望。
[Abstract]:The energy recovery of the moving arm is an effective way to further reduce the fuel consumption and exhaust emission of the hybrid power excavator. It is of great significance to improve the current situation of high energy consumption and high emission of the excavator. The related research can also provide some reference and reference for the energy recovery of other types of engineering machinery.
For the hybrid excavator, the introduction of energy recovery changes the control mode of the operation of the arm. How to ensure good energy saving and operability is the bottleneck of the practical application of the technology at the same time. In order to solve this problem, a new scheme and working principle of the energy recovery system of the moving arm is proposed in this paper: the system scheme is adopted. The hydraulic motor - generator energy recovery unit and the flow throttle valve structure, the idea of pressure compensation is introduced in the working principle, that is to control the generator to automatically adapt the electromagnetic torque to the load pressure. On the one hand, the pressure difference between the front and back of the throttle valve is constant and small, and then the opening of the valve can be adjusted to control the movement of the moving arm effectively, on the other hand, the liquid is controlled by the liquid. The pressure motor generator unit reuses the energy, and estimates the pressure difference of the throttle valve based on the vector control of the generator speed information and the flow pressure difference mapping relation, and applies it to the energy recovery system based on the pressure difference control, which can reduce the cost and complexity of the sensorless control scheme. In this paper, the key component of the energy recovery system, the hydraulic motor - generator unit, is studied in this paper. In view of the performance requirements of the energy recovery generator with high efficiency and low torque ripple, the parameters of the rotor structure are divided by the parameterized electromagnetic design model and the finite element analysis. The design method of step cooperative optimization has taken into account the efficiency and accuracy of the design. The control of the hydraulic motor generator unit is discussed at the electrical and mechanical aspects. The current controller combined with feedback and feedforward is designed and the speed controller with disturbance compensation is designed to ensure that it has more ideal dynamics in the mode of torque and rotational speed. A set of design and control methods for the energy recovery system of the moving arm are proposed in this paper, which can simultaneously achieve a good recovery of the manipulability and energy of the arm, and effectively promote the practical application of the energy recovery system of the arm in the hybrid excavator.
The contents of the chapters of the paper are as follows:
The first chapter expounds the importance of the research on the energy recovery of the excavator moving arm under the background of the energy shortage and the environment deterioration, introduces the research status of the energy recovery of the engineering machinery arm, analyzes the characteristics and the existing problems of several energy recovery schemes, and aims at the electric energy recovery system suitable for the hybrid power excavator. The component selection of the energy recovery unit of the hydraulic motor - generator is introduced, and the design and control methods of the permanent magnet generator are summarized, and the main contents of the research are put forward at the end.
In the second chapter, the energy recovery system of the dynamic arm of the hybrid excavator is studied. The performance characteristics of the system are analyzed, and the main performance evaluation indexes of the system are summarized, including energy saving and operation. A new system structure scheme for the hydraulic motor generator energy recovery unit and the series throttle valve is proposed. The mathematical model of the main components is used to analyze the loss of each link in the energy transfer flow, and the parameter design of the system is discussed, which lays a foundation for the further research of the component level.
In the third chapter, the design and optimization method of energy recovery generator is studied. Aiming at the performance requirements of keeping high efficiency and low torque ripple under the constraints of energy recovery generator, a design method is put forward to optimize the parameters of the rotor structure step by step. First, the minimum loss of the structure and size is the target, and the parameterized model is based on the model. The optimal stator structure parameters and magnetic induction intensity distribution are obtained by the particle swarm optimization (PSO), and the minimum wave distortion of the air gap magnetic induction intensity is the target. The finite element method is used to optimize the structure parameters of the permanent magnet, and the actual distribution of the magnetic induction intensity is consistent with the stator optimization results. The temperature rise under the intermittent operation is calculated and checked. The prototype of the energy recovery generator is developed and the performance and parameters are tested. The test results verify the effectiveness of the design and optimization methods.
In the fourth chapter, the control of the energy recovery unit of the hydraulic motor generator is studied. The current control of the permanent magnet generator is studied at the electrical level. In order to reduce the influence of the anti electromotive force, a proportional integral current controller with feed-forward compensation is designed. The speed control of the hydraulic motor generator unit is studied at the mechanical level, and the hydraulic horse is aimed at the hydraulic horse. The disturbance compensation is introduced to improve the anti-interference ability of the system. A corresponding simulation model is set up, and the simulation study of the designed control method is carried out. A test bench based on the simulated loading is built and the test results are carried out. The test results show that the torque and rotation of the hydraulic motor generator unit are in the torque and rotation. The speed mode has good control performance, which provides support for further research on the control method of the boom energy recovery system.
The fifth chapter studies the control method of the energy recovery system which has a leading influence on the manipulability of the moving arm. Combined with the structure and characteristics of the system, three control methods are proposed: direct speed control, adjusting the speed of the hydraulic cylinder by controlling the speed of the hydraulic motor generator unit, the throttle valve is basically in full open state; the load pressure control, Through the throttle valve, the speed of the hydraulic cylinder is adjusted, the target torque of the unit is determined according to the load pressure, the pressure difference of the throttle valve is controlled, and the throttle valve is also regulated by the throttle valve, but the target torque is determined according to the closed loop control of the throttle valve. The transmission function of the system in various methods is derived, and the dynamic performance is analyzed and compared. It is proved that the pressure difference control of the throttle valve has the best frequency response and damping characteristics. A test bench for the energy recovery test of the dynamic arm of the hybrid excavator is set up and the experimental results are carried out. The experimental results verify the theoretical analysis.
In the sixth chapter, the energy recovery system based on the pressure difference control method is further studied. Through the analogy with the differential pressure compensator, the principle of the energy recovery is extended from the moving arm down process to the whole process including the lifting and the lower, and the recovery energy of the two conditions is analyzed. In order to avoid the use of additional pressure difference sensing In order to reduce the cost and complexity of the system, a sensorless control method is proposed, which uses vector control feedback information of the generator and the flow pressure difference mapping relation of the throttle valve to estimate the pressure difference. The equivalence of the sensorless control is demonstrated from the steady state and the dynamic. Finally, the two aspects of operation and energy saving are carried out. A large number of experimental research results show that the proposed dynamic arm energy recovery system and control method have good dynamic performance in the typical operation process, and can adapt to various action requirements. The actual recovery energy is consistent with the theoretical analysis, the total recovery efficiency is between 40%-50% and has a certain improvement space.
The seventh chapter summarizes the main research work and innovation of the paper, and prospects the future research directions.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU621

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