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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Generalized theory of static power frequency changers

Gyugyi, L. January 1970 (has links)
The thesis is concerned with static frequency changers, using solid-state switching devices, capable of directly (i.e. without an intermediate dc link) converting polyphase ac power of a given frequency to single or polyphase power of a chosen frequency. The thesis consists of two parts. The first part, comprising five chapters, is devoted to the study of ideal frequency changers operated from ac Sources having zero internal impedance. The second part, comprising two chapters, considers sources with finite internal impedances . Chapter 1 introduces the basic concepts of static frequency conversion, outlines the basic mathematical models representing static frequency changers and defines the output and input performance indicators. Chapter 2 presents a detailed investigation of that class of three-pulse frequency changers which will be studied in the thesis. A large portion of the chapter is devoted to the study of output waveform generation. The mathematical tools of the investigation, existence matrices and modulating functions, are introduced and defined. Analytical expressions for output waveforms corresponding to various practical modulating functions are derived and the related performance indicators are computed. Assuming a given desired output performance, criteria for an optimal modulating function are established. It is proved that only one system can generate an output waveform conforming to the postulated prerequisites. This system is termed the "Unrestricted" Frequency Changer. Expressions for the input current waves are also derived in this chapter and the corresponding input performance indicators are determined . The concept of a new frequency changer having the unique property of providing unity input power factor, regardless of the load, is introduced. This system is termed the "Unity Power Factor" Frequency Changer. In Chapter 3 the previous results are extended to systems having pulse numbers which are integral multiples of three. Chapter 4 is devoted to the study of output voltage control. Three basic methods are analysed and detailed quantitative data for output voltage and input current waves, and the related performance indicators, are presented in graphical form. In Chapter 5 special aspects of static frequency changing are investigated. It is shown that the input displacement factor is variable. The concept of the "Controlled Displacement Factor" Frequency Changer is introduced It is proven that the naturally commutated cycloconvertor is theoretically equivalent to a particular "Controlled Displacement Factor" Frequency Changer. Chapter 6 presents a detailed analysis of the "Unrestricted" Frequency Changer, operated from an ac source with finite internal impedance. The basic conditions are defined and an outline is given of the techniques of symmetrical components used for the analysis. The input current, input terminal voltage and output voltage waveforms are expressed in terms of the input terminal impedance and the positive, negative and zero sequence components of the output currents. The equivalent sequence impedances and the output impedance matrix are derived . The output voltage unbalance is computed under various conditions and presented in graphical form. The relationships between the amplitudes of the unwanted components in the output waveform and the resonant frequency of the input terminal circuit are also graphically presented. The results obtained are verified by computer simulations. In Chapter 7 a similar analysis of the "Unity Power Factor" Frequency Changer is carried out . The computed data are also graphically presented. Again, the results are verified by appropriate computer simulations.
2

The Research of Organizational Climate,Management Control System and Performance-A Case Study of A and B Companies

Chen, Fu-Yuan 08 September 2011 (has links)
The main goal of this research is to discuss the impact on organization management performance based on organizational climate and management control system. This research analyzes the corporate organizational climate by organizational climate scale (Litwin & Stringer, 1968); moreover, the type of the corporate management control system is identified by face-to-face interview and the performance of management is measured by financial indicators. The result of this research shows that there is a significantly positive correlation between management control type and the subjective performance of management, and therefore the type of management control has significantly influence on the subjective performance of corporate management. As for the aspect of management control type, the management performance using procedure control and output control simultaneously would be better than that only using output control
3

Modulární síťové zařízení pro měření a ovládání / Modular network devices for measuring and control

Lízner, Miroslav January 2011 (has links)
This diploma thesis deals with ethernet embeded device. The main goal of this work is to develop device for reading values, input states and for output control. The hardware solution based on STM32 mitrocontroller is described in practical part of this work.
4

Creative Control : How to Manage Innovation and New Product Development

Haapanen, Heta-Liisa, Kaukonen, Ulla January 2010 (has links)
<p>The topic of this research is to explore to what extent innovation and new product development (NPD) are managed with formal and informal control mechanisms respectively and in combination in five international food industry companies. The topic deals with finding an understanding of controlling innovation processes which require freedom to some extent but at the same time are to be managed in order to keep track of the resources. Cases’ selection was designed to bring variation and catch the complexity of the phenomenon by studying one prime case and validating the results with four minor case companies’ results. The findings of the study indicate that first of all formal and informal control mechanisms coexist and interact and secondly that a more informal and personalized take is beneficial in R&D settings.</p>
5

Creative Control : How to Manage Innovation and New Product Development

Haapanen, Heta-Liisa, Kaukonen, Ulla January 2010 (has links)
The topic of this research is to explore to what extent innovation and new product development (NPD) are managed with formal and informal control mechanisms respectively and in combination in five international food industry companies. The topic deals with finding an understanding of controlling innovation processes which require freedom to some extent but at the same time are to be managed in order to keep track of the resources. Cases’ selection was designed to bring variation and catch the complexity of the phenomenon by studying one prime case and validating the results with four minor case companies’ results. The findings of the study indicate that first of all formal and informal control mechanisms coexist and interact and secondly that a more informal and personalized take is beneficial in R&amp;D settings.
6

Inspekční objektový senzor / Object inspection sensor

Neradilková, Aneta January 2017 (has links)
Object inspection sensor is a device that is mainly used in the automation of the production process. The Diploma Thesis deals with the familiarization of optical inspection systems, survey and comparison of companies of these systems in the Czech Republic. ELLA-CS company and dafault state output control products in her workplace is presented in the Diploma Thesis. The next part concerns the design of the inspection system for the company ELLA-CS, which is designed on the platform Raspberry. The thesis also deals with the implementation of the inspection system, which describes the hardware and software of this system. The last part is intended to discuss the results and suggestions for improving the inspection.

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