泵腔结构参数对压电气泵性能影响

为了探究泵腔结构参数对压电气体隔膜泵性能的影响,该文设计了一种压电气体隔膜泵的泵腔结构。首先简述了泵腔的结构设计与工作原理,推导出泵腔出口气流速度的表达式,通过仿真得出泵腔高度、气孔直径对腔体内的瞬时气压、气流速度及气体流量的影响。最后制作了泵腔样机并应用在压电气体隔膜泵中,进行了实验测试及理论分析对比。结果表明,实验结果与理论分析相吻合,输出流量随着腔高的增大而减小,随着气孔直径的增大而增大,这为压电气体微泵的腔体设计提供了理论参考。     

磁悬浮制冷与传统压缩制冷技术比较

磁悬浮轴承是高技术含量产品,由于其价格昂贵,过去只被用于航天工程。在传统的制冷压缩机中,机械轴承是必须的部件,并且要有润滑油循环系统来保证机械轴承工作。据统计,在所有烧毁的压缩机中,90%是润滑失效引起的。而机械轴承不仅会产生摩擦损失,润滑油也会随制冷循环而进入到热交换器中,在传热表面形成的油膜成为热阻,影响热交换器的效率,系统中润滑油过多会对制冷效率带来很大的影响。但是,轴承在压缩机中是不可或缺的部件。磁悬浮轴承是一种利用磁场,使转子悬浮于空中,在旋转时不会产生机械接触和机械摩擦,因此磁悬浮轴承不再需要机械轴承以及机械轴承所必须的润滑系统。在制冷压缩机中使用磁悬浮轴承,可有效避免由于使用机械轴承而产生的一系列故障。当今新型的制冷压缩机正是应用了磁悬浮轴承技术。     

磁力弹簧式气体隔膜泵的研究

提出了利用磁力弹簧构造气体隔膜泵,并对气体隔膜泵的具体结构与工作原理进行阐述。对气体隔膜泵的核心部件压电振子、被动截止阀等进行选择和设计;对磁力弹簧结构进行分析,通过理论计算确定磁力弹簧的轴向力与轴向间隙的关系;通过实验方法,对不同阀口直径气体隔膜泵的输出流量与压力进行验证。结果表明,磁力弹簧构造气体隔膜泵能大幅提高泵体容积变化率,磁力弹簧能提供很好的刚度,输出流量、压力与同类气体泵相比大幅提高。     

抗磁悬浮原理在执行与传感方面的应用研究及发展

抗磁悬浮是利用物质对磁场的排斥力实现磁悬浮,作为磁悬浮技术的一个分支,是一种真正意义上的无接触悬浮。按照不同的应用领域,从传感器、执行器、能量采集器、生物科学以及自组装等方面对抗磁悬浮结构进行了具体的介绍,概述了抗磁悬浮在各个领域的工作原理、结构组成以及适用范围,分析了抗磁悬浮发展现状及应用前景。研究得出抗磁悬浮具有室温下无源工作、自主稳定悬浮以及适宜在微器件尺度下使用等优点,其系统简单、可靠性高、系统体积小且质量轻,在工程技术上有重大的意义。     

图解分析法讲解无轴承电机磁悬浮控制原理

在回顾电机中的洛伦兹力和麦克斯韦力基础上,本文通过理论解析介绍了无轴承电机产生稳定径向悬浮力的基本条件。笔者以二极悬浮控制四极无轴承电机为例,针对几个典型时刻产生出的径向磁悬浮力,对无轴承电机磁悬浮控制原理进行了图解分析。教学实践表明,采用本文解析推导和图解分析相结合的讲解方法,便于快速且深入地理解掌握无轴承电机这种新型电机的基本工作原理。     

基于STM32的磁悬浮轴承数字控制器设计

针对传统磁悬浮轴承转子系统开环不稳定、非线性和强耦合等特性,需要对电磁力施加主动控制才能使转子稳定悬浮的缺陷,本文设计了一种基于STM32的磁悬浮轴承数字控制器方案。该控制器以ARM STM32F407ZGT6微处理器为核心,设计了电源转换、电涡流位移传感器、功率放大器控制、实时时钟以及声光报警等硬件电路;同时编写了基于国产嵌入式实时操作系统RT-Thread的多线程软件框架,实现了数据采集、PID算法等功能。实验结果表明,该数字控制器下的磁悬浮轴承转子系统可以在200ms内达到稳定悬浮状态,运行可靠、实时性好、速度快、抗干扰能力强。     

基于DSP与FPGA的主动磁悬浮轴承控制系统设计

<正>控制系统作为主动磁悬浮轴承的核心，决定了磁轴承的工作性能。本文设计了一种基于DSP与FPGA的主动磁悬浮轴承控制系统，它以DSP实现核心控制，FPGA采集数据和输出控制信号，设计了电源模块、传感器及测量模块、隔离与功率放大模块等硬件电路。同时，控制器采用了改进的线性自抗扰控制和PI双闭环策略，编写了软硬件程序。仿真与实验结果表明，该系统能在不加转速的情况下令转子稳定悬浮，转子最大偏移量不超过14.74μm，处于保护范围0.15mm以内，基本围绕中心点运动，满足设计要求。     

磁悬浮轴承磁场均匀性测试系统的设计

介绍了一种基于霍尔传感器的磁悬浮轴承磁场均匀性测试系统的设计。该系统由信号采集、信号处理、显示电路和控制电路等组成,并通过串口实现计算机实时显示磁悬浮轴承的磁场强度并保存数据。该系统具有测试一致性好、精度高及简单等特点,能运用于磁悬浮轴承磁场的检测,提高产品的合格率。     

基于DSP的磁悬浮轴承数字控制系统设计

文章介绍了磁悬浮轴承的组成及其工作原理 ,分析了磁悬浮轴承两个重要性能指标控制精度和可控转速与A/D转换器、传感器、功率放大器以及控制算法之间的相互关系。以TMS32 0F2 4 0为核心 ,设计实用电磁轴承控制系统。提出了以多文件工程结构的软件设计方法 ,提高软件的可读性、可维护性和可扩展性。     

基于有限元分析的直流电机控制策略

无轴承无刷直流电机集成了直流和交流电机的优点,具有重要的实际应用价值,针对传统悬浮力控制方法存在工作复杂、逆变器通断频繁等缺陷,为了提高磁悬浮力的控制效果,提出了基于有限元分析的无轴承无刷直流电机悬浮力控制策略。首先对无轴承无刷直流电机的结构以及悬浮力产生的原理进行了分析,然后采用有限元分析法对电机转矩和悬浮力进行计算,从而实现无轴承无刷直流电机控制,最后采用Matlab/Simulink工具对其性能进行测试与验证。结果表明,本文策略可以提高转子悬浮的稳定性,能够保证无轴承无刷直流电机的正常运行。     

A linear induction motor control system for magnetically levitatedcarrier system

An electromagnetic suspension system has been developed that cuts off electric power-collecting devices from a magnetically levitated vehicle. This system makes it possible to transport materials with no mechanical contact at all between the vehicle and ground facilities. A control system for linear induction motors used in the magnetically levitated carrier system is described. The system was developed to transport materials in an environment which must be kept free from even microscopic dust motes and trivial noise. The linear induction motor control method used for positioning a vehicle at the station is described along with several kinds of switches without any mechanical motion in the ground facilities. A supervisory control system for the magnetically levitated carrier system is also discussed     

Design,implementation and self-tuning adaptive control of maglev guiding system

This paper presents a self-tuning adaptive control (STA control) for a magnetically levitated (maglev) guiding system. The guiding system is a repulsive maglev system with a passive carrier and four active guiding tracks. Hybrid magnets exert the levitation forces, whereas the stabilizing forces are produced by electromagnets. Given such a system, an STA stabilizing controller is developed, and the thorough analysis of the stability property is also proposed. It is shown that without precise knowledge of various components, the overall system stability and the regulating precision are assured, which validates the hereby proposed system. From the simulation and experimental results, the performance of the system design and the enforced control mechanism is demonstrated successfully.     

Robust Angle-Sensorless Control of a PMSM Bearingless Pump

In the semiconductor industry, where bearingless pump systems are employed as the state-of-the-art technology, the trend goes toward higher fluid temperatures (150 $^{circ}hbox{C}$ and more) in order to further increase process efficiency. This fact translates into the requirement of a high-temperature bearingless pump system and/or the elimination of thermal-critical components such as Hall sensors. This paper introduces a new method for a hall-sensorless control of a permanent-magnet synchronous machine bearingless pump in its operating range from 0 to 8000 r/min and from zero load to full load. The sensorless operation is performed by the following three novel control functionalities: a controlled startup routine, enabling a sure levitation and zero-angle setting; an open-loop angle estimation based on stator voltage and stator current measurement and known machine parameters; and an angle synchronization establishing a robust operation of the pump in the whole operating range even for a large machine parameter drift. In particular, considering the temperature degrading of the permanent-magnet flux density, the novel robust control concept is of great benefit for bearingless pump systems employed in high-temperature applications.      

A novel bearingless interior permanent magnet slice motor driven blood pump

A 2-pole bearingless interior permanent magnet (IPM) motor with slice rotor configuration is presented in this paper. A novel IPM rotor is designed considering direct and indirect operational specifications such as force constant, torque constant, axial/radial stiffness and cogging torque. Cogging torque and its resulting vibrations affect motor and levitation operation significantly. Hence, various rotor configurations are simulated using the finite element method to develop a topology that minimizes these phenomena. The final topology is tested for closed-loop levitation and speed control. The motor is also tested for its intended application as a blood pump. A mock circulatory loop is developed to measure the performance of the pump. The simulation results, experimental control system performance and pump performance results are shown and explained in the paper.     

Optimization of a hybrid magnetic bearing for a magnetically levitated blood pump via 3-D FEA

In order to improve the performance of a magnetically levitated (maglev) axial flow blood pump, three-dimensional (3-D) finite element analysis (FEA) was used to optimize the design of a hybrid magnetic bearing (HMB). Radial, axial, and current stiffness of multiple design variations of the HMB were calculated using a 3-D FEA package and verified by experimental results. As compared with the original design, the optimized HMB had twice the axial stiffness with the resulting increase of negative radial stiffness partially compensated for by increased current stiffness. Accordingly, the performance of the maglev axial flow blood pump with the optimized HMBs was improved: the maximum pump speed was increased from 6000 rpm to 9000 rpm (50%). The radial, axial and current stiffness of the HMB was found to be linear at nominal operational position from both 3-D FEA and empirical measurements. Stiffness values determined by FEA and empirical measurements agreed well with one another. The magnetic flux density distribution and flux loop of the HMB were also visualized via 3-D FEA which confirms the designers’ initial assumption about the function of this HMB.     

压电驱动膜片式微型气泵

提出一种结构新颖的压电驱动膜片式微型气泵，对其输出流量、膜片的振幅等参数进行了理论分析，在此基础上设计、制作了微型气泵样机，并进行了测试实验。这种气泵在结构上充分利用了双压电梁端部位移大的优点，并利用两根双压电梁将膜片悬起，增加了容积变化率和输出流量，并具有结构简单，功耗低，厚度小，无电磁噪音，可靠性高等优点，在微型电子器件的冷却、微型燃料电池换气等方面显示出良好的应用前景。根据实验，微型气泵的一阶固有频率约为120Hz，在谐振状态下，当驱动电压为50V时，其输出流量为192mL／min，功耗小于23mW。     

基于全息谱的离心泵机运行状态识别

离心泵的维护与维修目前基本仍然采用经验判断和大修机制,泵机的运行状态没有具体的衡量标准,所以形成＂只可意会,不可言传＂的困境。针对此结合全息谱理论,提出利用全息谱分析技术,实现离心泵的运行状态量化,实现泵机在诊断的基础上进行预知维护维修。     

One-axis hysteresis motor driven magnetically suspended reaction sphere

This paper presents the design, modeling, control, and experimental results for a one-axis magnetically suspended reaction sphere (1D-MSRS) driven by a hysteresis motor. The goal of this work is twofold: (a) to conduct a preliminary study for magnetically suspended reaction sphere for three-axis spacecraft attitude control, and (b) study the potential of hysteresis motors for the reaction wheel/sphere drives. The 1D-MSRS uses a hysteresis motor with a spherical rotor made of solid steel. The rotor sphere is magnetically suspended in all translational directions, and is driven about the vertical axis by a bearingless hysteresis motor. We present the modeling and control of the magnetic suspension of the bearingless motor in the 1D-MSRS, and the hysteresis motor dynamics are analyzed by a hysteresis motor equivalent circuit model. The 1D-MSRS system has experimentally demonstrated a starting torque of 8.9 mNm under 0.7 A peak sinusoidal excitation current. With this excitation the sphere can run up to 12,000 rpm synchronously in the presence of air drag. This study demonstrates that the hysteresis motor has strong potential for use in high-speed, low-vibration reaction wheels.     

Modeling, design, and control integration: a necessary step in mechatronics

Future products require more sophistication and flexibility from both the hardware and software points of view. In particular, these products involve several energy domains, which is one reason for the new requirements for system design and the integration of design and control. These are important aspects not only for industrial research and development personnel but also for academicians. In this paper, a modeling and control system perspective relevant to the systems approach and fast adaptive control systems is first presented. Specifically, some of the important aspects are properties from graphical system representation, achievable performance, and fast control algorithms. A few applications are then presented to illustrate some system design requirements and control system characteristics. These applications emphasize the demand for high performance systems which has introduced an increasingly challenging system design problem. The applications discussed include high-speed robot manipulators, high-speed and high-precision magnetic bearing systems, atomic resolution systems, and their control using digital signal processing boards. Experimental results pertaining to the control of a five-axis magnetically levitated turbopump are presented.