【作者】 周俊杰；

【导师】 李威；

【作者基本信息】 中国矿业大学 ， 机械电子工程， 2022， 硕士

【摘要】 刮板输送机作为综采工作面“三机配套”设备之一,承担着煤炭运、装、卸的任务,其性能的好坏直接影响着煤炭的安全、高效开采。本文提出采用低速大扭矩的永磁同步电机替代三相异步电机并直接驱动刮板输送机,取消了液力耦合器和减速器等中间易损传动环节,符合矿用刮板输送机大功率、高效率、少故障、降能耗等性能方面要求。然而刮板输送机在运行过程中不可避免出现链条断裂、卡死等非稳态工况,影响设备的正常运行。为保证系统高可靠性运行,本文通过理论数学建模、模拟仿真分析以及实验验证等方式,对永磁直驱刮板输送机非稳态工况下系统的动态特性展开研究。同时,考虑到永磁直驱刮板输送机主传动系统内外参数的调整不合理,可能引起的分岔、混沌等现象,最终导致主传动系统发生失稳的扭转振动。本文分别针对非线性刚度及结构间隙作用下永磁直驱主传动系统的扭振特性展开了分析研究。主要研究内容包括:(1)根据刮板输送机机械组成结构和链轮链环系统传动特点,构建了双端驱动刮板输送机整机动力学模型,并综合考虑了工作运行时运行阻力、刮板链预紧力以及链轮链环传动的多边形效应等因素对系统的影响;对永磁同步电机进行分析,确定了永磁同步电机结构类型,建立其基本数学模型;最后,确定了i_d(28)0的电机矢量控制方法,分析了在该控制方式下的控制思路及坐标变换、脉宽调制等必要环节。(2)将刮板输送机动力学模型、永磁同步电机模型及电机矢量控制方式,通过转速、扭矩等参数为纽带联系起来,构建永磁直驱刮板输送机全局机电耦合动力学模型。利用仿真软件Simulink进行机电耦合模型的搭建,施加特定的边界条件,研究了稳态满载运行工况、非稳态运行工况(刮板链断链、刮板链卡链)下系统的动态特性。(3)针对非线性刚度影响作用下主传动系统的扭振特性,本文根据Lagrange-Maxwell方程来构建全局机电耦合扭振动力学方程。以一次项扭转刚度系数K为分岔参数进行研究,对其Hopf分岔的类型及稳定性进行分析,并通过在原系统中加入状态反馈器,对Hopf分岔进行控制;针对主传动系统存在结构间隙时系统的扭振特性,本文综合了分段非线性弹性力作用及考虑扭转角度的电机电磁转矩稳态模型,建立主传动系统扭振模型。利用分岔图、最大李亚普诺夫指数图、相图及庞加莱映射截面图等,得到弹性力中非线性项系数F_δ 不同取值对主传动系统分岔与混沌特性的影响。(4)借鉴动态负载模拟技术及参数等比例缩小方法,根据实验室现有的永磁同步电机及磁粉式测功机系统,对变频控制器软硬件进行设计,搭建了小比例等效负载模拟实验台,对永磁直驱刮板输送机系统动态特性进行实验验证。将第三章仿真得到的满载稳态运行、断链以及卡链三种工况下负载转矩,经参数缩放后通过测功机进行加载,最终得到小比例等效负载模拟实验台动态特性曲线。将实验结果与仿真结果进行对比,通过比较两者的变化规律,验证理论模型的正确性以及仿真结果的有效性。该论文有图56幅,表7个,参考文献93篇。更多还原

【Abstract】 Scraper conveyor,as one of the"three-machine supporting"equipment in comprehensive mining face,undertakes the task of coal transportation,loading and unloading.Its performance directly affects the safe and efficient mining of coal.In this thesis,permanent magnet synchronous motor with low speed and large torque is proposed to replace three-phase asynchronous motor and drive scraper conveyor directly,eliminating intermediate fragile transmission links such as hydraulic coupler and speed reducer,which meets the performance requirements of mine scraper conveyor in terms of high power,high efficiency,less faults and energy consumption.However,during the operation of scraper conveyor,unsteady conditions such as chain breakage and seizure will inevitably occur,which will affect the normal operation of the equipment.In order to ensure high reliability of the system,the dynamic characteristics of permanent magnet direct drive scraper conveyor under unsteady conditions are studied in this thesis by means of theoretical mathematical modeling,simulation analysis and experimental verification.At the same time,due to unreasonable adjustment of internal and external parameters of main drive system of permanent magnet direct drive scraper conveyor,bifurcation and chaos may occur,which ultimately leads to unstable torsional vibration of main drive system.In this thesis,the torsional vibration characteristics of permanent magnet direct drive main drive system under non-linear stiffness and structural clearance are analyzed and studied respectively.The main research contents include:(1)According to the mechanical structure of scraper conveyor and the driving characteristics of sprocket chain chain system,the dynamic model of double-end drive scraper conveyor was built,and the influence of operating resistance,scraper chain pretension and polygon effect of sprocket chain drive on the system were considered comprehensively.The permanent magnet synchronous motor is analyzed,the structure type of permanent magnet synchronous motor is determined and its basic mathematical model is established.Finally,the motor vector control method of i_d(28)0is determined,and the control ideas,coordinate transformation,pulse width modulation and other necessary links under this control mode are analyzed.(2)The dynamic model of permanent magnet direct drive scraper conveyor,permanent magnet synchronous motor model and its vector control method are combined with rotational speed,torque and other parameters to build the global electromechanical coupling dynamic model of permanent magnet direct drive scraper conveyor.The simulation software Simulink is used to build the electromechanical coupling model and apply specific boundary conditions to study the dynamic characteristics of the system under steady-state full-load operation conditions and unsteady-state operation conditions(scraper chain break and scraper chain snap).(3)In view of the torsional vibration characteristics of the main drive system under the influence of non-linear stiffness,this thesis constructs the global mechanical equation of electromechanical coupling torsional vibration according to Lagrange-Maxwell equation.Taking one-time torsional stiffness coefficient K as bifurcation parameter,the type and stability of Hopf bifurcation are analyzed,and the Hopf bifurcation is controlled by adding a state feedback into the original system.In view of the torsional vibration characteristics of the main drive system with structural clearance,this thesis establishes the torsional vibration model of the main drive system by combining the piecewise nonlinear elastic force and the electromagnetic torque steady-state model of the motor considering the torsional angle.By using bifurcation diagram,maximum Lyapunov exponent diagram,phase diagram and Poincare mapping section diagram,the influence of different values of non-linear term coefficient F_δon Bifurcation and chaos characteristics of main drive system is obtained.(4)Referring to the dynamic load simulation technology and the proportional reduction method of parameters,according to the existing permanent magnet synchronous motor and magnetic powder dynamometer system in the laboratory,the software and hardware of the frequency conversion controller are designed,and a small-scale equivalent load simulation test-bed is built to verify the dynamic characteristics of the permanent magnet direct drive scraper conveyor system.The load torque under the three working conditions of full load steady-state operation,chain breaking and chain clamping obtained in the third chapter is scaled by parameters,loaded by dynamometer,and finally the dynamic characteristic curve of small-scale equivalent load simulation test-bed is obtained.By comparing the experimental results with the simulation results,the correctness of the theoretical model and the effectiveness of the simulation results are verified.There are 56 pictures,7 tables and 93 references.更多还原