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首页> 外文学位 >Utilizing the connected power electronic converter for improved condition monitoring of induction motors and claw-pole generators.
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Utilizing the connected power electronic converter for improved condition monitoring of induction motors and claw-pole generators.

机译：利用所连接的功率电子转换器来改善感应电动机和爪形极发电机的状态监测。

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摘要

This thesis first investigates the stator turn-to-turn fault detection for induction motors fed by closed-loop inverter drives. A comprehensive survey of existing stator turn-fault detectors reveals that the major disadvantage of conventional methods is that the process of learning the inherent asymmetry of the induction motor is highly complicated. Such complexity directly limits the practicability of these methods in real world applications. In this work, it is discovered that motor current controllers in the closed-loop inverter can keep the three-phase current symmetrical no matter a stator turn fault exists or not. This unique feature is utilized to essentially eliminate the learning process of the motor inherent asymmetry during stator turn-fault detection. The proposed method is evaluated experimentally and the results show that the proposed fault detector is highly sensitive and easy to implement.;In addition to detecting a solid stator turn fault, an early warning of the stator insulation degradation is also highly desired. A stator thermal monitoring method is thus proposed in this work to protect the closed-loop inverter-fed induction motor from insulation degradation caused by thermal overload. The stator temperature is indirectly estimated from the stator resistance. The closed-loop inverter is used to inject a DC current into the motor windings in an online fashion. Since only the DC bus voltage sensor is available in typical closed-loop inverter drives, the major challenge of this method is how to accurately estimate the DC component of the motor terminal voltage despite inverter nonidealities. The proposed method is finally implemented in real time in a custom-built programmable inverter drive. The experimental results demonstrate that the method gives accurate and robust stator temperature estimation regardless the operating condition of the induction motor.;The health monitoring of claw-pole generators with built-in rectifiers is also studied in this thesis. Despite the limited literatures on the major failure modes of claw-pole generators, several common types of faults are successfully identified and studied in detail. Different from grid-connected AC generators, the built-in rectifier of the claw-pole generator makes it difficult to access the three-phase voltage and current measurements. Hence, conventional condition monitoring methods based on AC signals can no longer be used. To overcome this challenge, an experimental analysis is performed to better understand the overall waveforms and spectra of the voltage and current of the claw-pole generator. Several harmonic components in the output current spectrum are identified to be related to various faults of the claw-pole generator.;Faults of claw-pole generators are classified into two categories: External faults (or system-related faults) and internal faults. Specifically, the external faults of claw-pole generators studied in this thesis include the serpentine belt slip and serpentine belt defect. For the serpentine belt slip, the speed of the claw-pole generator is estimated indirectly by tracking the rectifier ripple frequency in the output voltage signal. Hence, the fault is reliably detected by comparing the estimated generator speed with the measured speed of the prime mover (vehicle engine). The defects on the serpentine belt, on the other hand, modulate the transmitted torque and speed of the claw-pole generator every belt cycle. It is therefore detected by monitoring some specific side-band current harmonics near the rectifier ripple frequency.;The internal faults of claw-pole generators studied in this thesis include the stator turn-to-turn fault, the rotor eccentricity, and the worn bearing. It is discovered that with unbalanced three-phase inputs, the output current of the rectifier will exhibit increased harmonic at one third of the rectifier ripple frequency. This signature is used to detect stator turn faults. Once the stator turn fault is detected, an analytical model of the claw-pole generator with fault is also derived to establish an accurate mapping relationship between the observed fault signature and the fault severity. The experimentally validated model enables the design of well-informed post-fault protection strategies, which prevent the stator turn fault from progressing into catastrophic generator failures while maintaining maximum limp-home capability of the vehicle. (Abstract shortened by UMI.)
机译：本文首先研究了由闭环变频器驱动的感应电动机的定子匝间故障检测。对现有定子故障检测器的全面调查显示，常规方法的主要缺点是，学习感应电动机的固有不对称性的过程非常复杂。这种复杂性直接限制了这些方法在实际应用中的实用性。在这项工作中，发现闭环逆变器中的电动机电流控制器可以使三相电流对称，无论是否存在定子转弯故障。利用此独特功能，可以从根本上消除定子故障检测期间电机固有的不对称性。通过实验对所提出的方法进行了评估，结果表明所提出的故障检测器具有很高的灵敏性和易于实现的优点。除了检测出可靠的定子匝间故障外，还非常需要对定子绝缘性能下降进行预警。因此，在这项工作中提出了一种定子热监测方法，以保护闭环逆变器供电的感应电动机免受热过载引起的绝缘劣化。定子温度由定子电阻间接估算。闭环逆变器用于以在线方式将直流电流注入到电机绕组中。由于在典型的闭环逆变器驱动器中仅提供DC总线电压传感器，因此该方法的主要挑战在于，尽管存在逆变器不理想的情况，如何准确估算电动机端子电压的DC分量。最终，所提出的方法在定制的可编程逆变器驱动器中实时实现。实验结果表明，该方法能够在不考虑感应电动机运行状态的情况下，对定子温度进行准确，可靠的估算。本文还研究了带内置整流器的爪极式发电机的健康监测。尽管关于爪极发电机的主要故障模式的文献有限，但成功识别和详细研究了几种常见类型的故障。与并网交流发电机不同，爪极式发电机的内置整流器使其难以获取三相电压和电流测量值。因此，不再能够使用基于交流信号的常规状态监视方法。为了克服这一挑战，进行了实验分析，以更好地了解爪极发生器的电压和电流的整体波形和频谱。识别出输出电流谱中的几个谐波分量与爪极发电机的各种故障有关。爪极发电机的故障分为两类：外部故障（或与系统相关的故障）和内部故障。具体来说，本文研究的爪极发电机的外部故障包括蛇形带滑移和蛇形带缺陷。对于蛇形皮带打滑，通过跟踪输出电压信号中的整流器纹波频率，间接估算爪形极发电机的速度。因此，通过将估计的发电机速度与原动机（车辆发动机）的测得的速度进行比较，可以可靠地检测出故障。另一方面，蛇形皮带上的缺陷会在每个皮带循环中调节爪极发电机的传递扭矩和速度。因此，通过监测整流器纹波频率附近的一些特定的边带电流谐波可以检测到该问题。；本文研究的爪极发电机的内部故障包括定子匝间故障，转子偏心率和轴承磨损。发现，在三相输入不平衡的情况下，整流器的输出电流将在整流器纹波频率的三分之一处表现出更高的谐波。该签名用于检测定子匝间故障。一旦检测到定子转弯故障，就会导出具有故障的爪极发电机的分析模型，以在观察到的故障特征和故障严重性之间建立精确的映射关系。经过实验验证的模型可以设计出消息灵通的故障后保护策略，该策略可防止定子转向故障发展为灾难性的发电机故障，同时保持车辆最大的li行能力。 （摘要由UMI缩短。）

著录项

  • 作者

    Cheng, Siwei.;

  • 作者单位

    Georgia Institute of Technology.;

  • 授予单位 Georgia Institute of Technology.;
  • 学科 Engineering Electronics and Electrical.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 240 p.
  • 总页数 240
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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