HBM-800T立式斜流泵磁悬浮轴承研究

发布时间：2018-04-04 23:29

本文选题：立式泵　切入点：混合磁轴承　出处：《兰州理工大学》2013年博士论文

【摘要】：目前,在国内大中型泵站的机组中,导轴承可靠性不高、使用寿命短、维修工作量大是一个普遍性的问题。目前使用广泛的水润滑橡胶轴承以及赛龙轴承在比较复杂的环境中工作时,容易出现轴承损坏或者是主轴损坏等问题,因此寻求一种稳定性高、使用寿命长的高性能导轴承,以保证立式斜流泵可靠运行是很有现实意义的。研究表明,磁轴承应用于立式斜流泵具备无接触、刚度和阻尼可调等传统轴承无法比拟的优势。课题在调研了国内、外立式斜流泵导轴承及磁悬浮轴承的现状和发展的基础上,以混合磁轴承应用于HBM-800T立式斜流泵进而改善该型立式斜流泵的运行稳定性为研究目标。考虑课题涉及机械学、力学、电磁学、控制理论、电子技术等多学科综合的特性,在不失系统一般性的前提下,突出研究重点,分别研究磁轴承新结构、叶片振动与转子及磁轴承耦合动力学、鲁棒控制等系统核心组成部分。主要工作及成果如下： 1.提出一种应用于立式斜流泵的新型混合径向磁轴承,这种混合磁轴承是永磁磁轴承和电磁磁轴承的组合。其中永磁磁轴承采用的是斥力型Halbach阵列永磁环堆叠结构,主动磁轴承采用8磁极结构,其中4对磁极径向分布,每对磁极轴向布置,永磁磁路与电磁磁路相互独立。小扰动偏移可以由被动磁轴承消除；扰动较大时,转子的位移由永磁磁轴承和电磁磁轴承共同控制,从而在一定程度上降低主动磁轴承的功耗。研究结果表明,新型混合磁轴承应用于立式斜流泵具备节能及可控的优点。 2.立式斜流泵转子较长,运转过程中,容易产生振动,尤其当泵高速运转时,容易发生叶片与壳体碰摩,非线性振动等有害因素,因此研究转子动力学理论,有利于解决泵的非线性动力学问题。课题建立一个叶片-转子-磁轴承系统的非线性动力学模型来分析叶片、转子和磁轴承之间的相互作用。利用Lagrange方程获得系统的耦合动力学微分方程。采用集中质量法、正交变换及周期变换将具有时变系数的耦合方程转化为常系数微分方程。数值计算结果表明这种系统具有丰富的非线性动力学现象,进入混沌的道路是通过阵发方式实现的。随后混沌运动演化为周期1运动,退出混沌运动状态；通过在较宽的转速范围数值计算表明,系统响应是倍周期运动,说明系统响应在转速大范围内是稳定的。虽然出现局部混沌运动,但转子无量纲位移振幅不大,远小于永磁轴承工作气隙,没有发生碰摩现象。 3.磁悬浮轴承除了无接触外,还有一个很显著的特点就是磁轴承的刚度可通过设计合适的控制系统按控制规律调整。所以研究混合磁轴承系统的组成及相关结构参数与控制系统的承载能力及刚度特性很有必要。课题采用电流分散控制策略,考虑功率放大器、控制电路和位移传感器增益特性,以及位移传感器位置耦合问题,并对系统状态矩阵及输入矩阵进行强制解耦,进而实现新型混合磁轴承的转子系统进行建模。通过以上步骤已经得到单个自由度上的磁轴承-转子系统传递函数,为系统控制器的设计奠定基础。 4.提出一种应用于立式斜流泵磁轴承转子控制系统的L2鲁棒控制器。由于目前磁悬浮轴承系统的动态特性还不能完全被人们掌握,很难得到磁悬浮轴承系统精确的数学模型,即存在模型“不确定性”。这些“不确定性”的主要来源是磁轴承电磁铁与转子之间以及与所处的环境体现出来的多场耦合问题。针对立式斜流泵混合磁轴承工作特点,首先将磁悬浮轴承电流控制器的设计问题转化为标准的L2问题进行设计。其次,基于无源化理论及递推解法求出系统的存储函数,并证明满足耗散不等式及闭环系统在原点全局渐近稳定。最后,用Matlab对L2控制的立式斜流泵磁悬浮轴承系统进行仿真,并与PID控制器的控制效果进行比较研究。结果表明,L2鲁棒控制策略相对PID控制策略更能有效抑制未知外扰动的影响。 5.最后,通过立式斜流泵磁悬浮轴承系统的简化模型实验研究,结果表明,磁悬浮轴承系统中转子能实现稳定悬浮,响应快,相移小以及具备干扰抑制性能。
[Abstract]:At present, in the domestic large and medium-sized pumping unit, guide bearing reliability, short service life, maintenance workload is a common problem. The use of water lubricated rubber bearings widely and Thordon bearings in complex environment, prone to damage or spindle bearing damage and other problems, so seeking a high stability, long service life and high performance bearing, in order to ensure the reliable operation of vertical mixed flow pump is of great significance. The research results show that applying the AMBs to no contact with the vertical mixed flow pump, the stiffness and damping adjustable bearing and other traditional incomparable advantages.
Study on the research of the domestic and foreign vertical diagonal flow pump guide bearing and magnetic bearing of the present situation and development on the basis of the hybrid magnetic went for running stability of HBM-800T vertical mixed flow pump and improve the vertical oblique flow pump as the research object. Topics related to mechanics, mechanics, electromagnetics, control theory, electronic properties technology of multiple disciplines, without losing generality under the premise of system, highlighting the focus of study, respectively, a new structure of magnetic bearing and rotor blade vibration coupling and magnetic bearing dynamics, robust control system is the core part.
The main work and results are as follows:
1. new hybrid radial magnetic bearing for vertical oblique flow pump, the hybrid magnetic bearing is a combination of permanent magnet bearings and electromagnetic magnetic bearings. The permanent magnet bearings using the repulsion type Halbach array permanent magnet ring stack structure using 8 pole structure of active magnetic bearings, including 4 pairs of pole radial distribution and each pair of magnetic poles arranged axially, permanent magnetic circuit and electromagnetic circuit are independent of each other. The small disturbance offset can be eliminated by passive magnetic bearings; disturbance is larger, the rotor displacement controlled by permanent magnet bearings and electromagnetic magnetic bearings, active magnetic bearings to reduce the power consumption in a certain extent. The results show that the new hybrid magnet bearing used in the vertical diagonal flow pump has the advantages of energy saving and controllable.
2. vertical diagonal flow pump rotor is longer, the process of operation, easy to produce vibration, especially when the pump is running at high speed, prone to leaf and shell rubbing, nonlinear vibration and other harmful factors, so the research on rotor dynamics theory, to solve the problems of nonlinear dynamics analysis of vane pump. The nonlinear dynamic model of subject establishment of a blade the rotor magnetic bearing system, the interaction between the rotor and the magnetic bearing. The coupling dynamics system of differential equations by Lagrange equation. Using the lumped mass method, orthogonal transform and periodic transform coefficients with coupled equations sometimes into differential equations with constant coefficients. The numerical results show that there exists the complicated nonlinear dynamics in the system, the road to chaos is realized by intermittent way. Then chaotic evolution period 1 motion, chaotic motion through the exit; In the wide speed range of numerical calculation shows that the system response is double period motion, the system response speed in large range is stable. Although the local chaotic motion, but the dimensionless rotor displacement amplitude is far less than the permanent magnet bearing working gap, no rubbing phenomenon.
3. in addition to magnetic bearings without contact, there is a very significant feature is the magnetic bearing stiffness can be controlled by appropriate system design according to control law adjustment. So carrying capacity study on composition and structure parameters and control system of hybrid magnetic bearing system and stiffness characteristics is necessary. The current decentralized task considering the control strategy, power amplifier, control circuit and sensor gain characteristics, and the displacement sensor position coupling problem and forced decoupling of system state matrix and input matrix, and then realize the new hybrid magnetic bearing rotor system is modeled. Through the above steps have been a single degree of freedom magnetic bearing - rotor system transfer function. To lay the foundation for design of system controller.
4. this paper proposes a vertical diagonal flow pump control system of magnetic bearing rotor L2 robust controller. Due to the dynamic characteristics of magnetic bearing system is currently still not fully been grasp, it is difficult to get the accurate mathematical model of the magnetic bearing system, namely the existence of model uncertainty. The main sources of the uncertainty is between the electromagnet and the rotor magnetic bearing and the environment to reflect the multi field coupling problem. The vertical diagonal flow pump hybrid magnetic bearing characteristics, firstly the design problem of magnetic bearing current controller is transformed to the standard L2. Secondly, and recursive solution for storage function of the system is based on the passivity theory, and prove the dissipative inequality and the closed-loop system globally asymptotically stable at the origin. Finally, simulation of vertical oblique flow pump magnetic bearing system controlled by L2 Matlab It is compared with the control effect of PID controller. The results show that L2 robust control strategy is more effective than PID control strategy in suppressing the influence of unknown external disturbances.
5., finally, through the simplified model experiment of the magnetic suspension bearing system of vertical diagonal flow pump, the experimental results show that the rotor in the maglev bearing system can achieve stable suspension, quick response, small phase shift and interference suppression performance.

【学位授予单位】：兰州理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH133.3

【参考文献】