Fault Mechanism

2016 ◽  
pp. 62-118
Keyword(s):  
Electric Power ◽  
Electromagnetic Interference ◽  
Power Converters ◽  
Failure Process ◽  
Destructive Effect ◽  
Special Factor ◽  
Main Factors ◽  
Fault Mechanism ◽  
Failure Factors

Static and rotary electric power converters have different structures but there are common failure factors in both of them. In this chapter, causes of failure in electric power converters is described. All of the failure factors which are described in this chapter are catastrophic factors and lead to destructive damage in the systems. Other types of failure without destructive effect on converter like electromagnetic interference will be presented in the next chapters. All descriptions are based on details of operation of the converters which were presented in the previous chapter. Over temperature, over voltage, mechanical forces and environmental effects like humidity are the main factors of failure in systems. Origins of these factors are described in this chapter. Over temperature is a special factor among them because other failure factors finally act as over temperature in failure process of the converters. Since over temperature is the main failure factor in electric power converters, loss model of components in electric power converters are presented in details. In addition, practical technique for measuring power loss is described. Sample industrial examples of damaged equipments due to these failure factors are shown to give a real sense to reader about failure results.

Availability

2016 ◽  
pp. 339-371
Keyword(s):  
Electric Power ◽  
Electromagnetic Interference ◽  
Power Converters ◽  
Operating Voltage ◽  
Repairable Systems ◽  
Alarm Management ◽  
The Subject ◽  
Influence Of Noise ◽  
Catastrophic Faults

Protection methods, which were described in the previous chapter, save the converter against non-catastrophic faults. However, this method saves the converter but it also takes the converter out of the service. The subject of this chapter is converters that are not damaged but can not operate normally. In this chapter, availability of electric power converters as a most important but usually forgotten parameter is described. The concept of availability was originally developed for repairable systems that are required to operate continuously. It is explained that a system may be unavailable while none of its parts damaged. In fact, there is an important difference between reliability and availability. A converter may be highly reliable but unavailable and vice versa. One of the most important factors for this undesired state is influence of noise. In this chapter, electromagnetic interference and certain methods for reducing its undesired effects on electric power converters are presented. Electric power converters are usually the source of electromagnetic noise due to high operating voltage and/or current. Various techniques for safe operation of sensitive systems that operate close to these converters are described. In the last part of chapter, alarm management is presented based on availability concept. This method is used to prevent fast shutdown of important systems due to dispensable faults.

Stress Reduction

2016 ◽  
pp. 262-301
Keyword(s):  
Electric Power ◽  
Design Process ◽  
Stress Reduction ◽  
Printed Circuit Board ◽  
Power Converters ◽  
High Amplitude ◽  
Power Converter ◽  
Operating Conditions ◽  
Circuit Board ◽  
Inrush Current

After evaluation of reliability in the previous chapters and its consideration as a converter figure of merit, in this and the next chapters, guidelines for improvement of reliability are presented. These methods are used in both design and operation process of the converter. The focus of this chapter is on the component stress reduction in the design process. Based on background of chapter two, reliability of a converter increases if it operates at a set point with low stress. It is assumed that the converter is under design process or operates without fault. The methods for reliability improvement in faulty converters are discussed in the next chapters. In this chapter, methods for reducing electric field are described at both system and printed circuit board level. Low temperature operating conditions for an electric power converter are described and tools for this goal are presented. Series connection for voltage sharing and parallel connection for current sharing is explained. Novel control methods of power converters for reducing the complexity and reliable operation are presented. Control of inrush current as a typical transient problem in electric power converters is presented. Methods for preventing the over stress condition on the components in faulty cases are described. Techniques for reducing mechanical and environmental stress are expressed. Mechanical dampers for preventing the high amplitude vibration and insulating colors against humidity are presented. Industrial and real samples are presented to demonstrate application of the proposed methods.

Miniature turbo-Brayton technologies for space-borne thermal-to-electric power converters

2002 ◽  
Author(s):  
Mark V. Zagarola ◽  
Walter L. Swift ◽  
John A. McCormick ◽  
Michael G. Izenson
Keyword(s):  
Electric Power ◽  
Power Converters

Failure Process and Mechanism Analysis for the Connecting Rod of Diesel Engine

2012 ◽  
Vol 463-464 ◽  
pp. 1597-1600
Author(s):  
Ying Kui Gu ◽  
Kang Hu ◽  
Jing Li
Keyword(s):  
Diesel Engine ◽  
Material Properties ◽  
Treatment Process ◽  
Failure Process ◽  
Organization Structure ◽  
Scientific Basis ◽  
Mechanism Analysis ◽  
Connecting Rod ◽  
Fault Mechanism ◽  
Physical And Chemical

The operational fault of diesel engine caused by losing the required function in running is a random phenomenon. It needs to collect a large number of fault samples and reliability data to reveal the fault occurrence rule and describe it with mathematical method. In this paper, the fault law and mechanism of the engine connecting rod were researched by the physical and chemical analysis of the fault samples. The fault reasons and the fault mechanism can be found through the analysis of the organization structure, material properties, process features, heat treatment process and other reliability information of the fault sample. It can provide scientific basis for the failure exclusion as well as the optimization and improvement of connecting rod structure.

Quantitative Analysis for Near-Field Characteristics of Converter Circuits

2011 ◽  
Vol 48-49 ◽  
pp. 858-862
Author(s):  
Wei Zhang
Keyword(s):  
Finite Element ◽  
Quantitative Analysis ◽  
Electric Power ◽  
Electromagnetic Interference ◽  
Industrial Development ◽  
Near Field ◽  
Power Electronic ◽  
Topology Structure ◽  
Component Design ◽  
Power Electronic Circuits

With the electric power industrial development, electric power device was abroad using as the core of switch converter. For a clear near-field characterization quantitative electromagnetic interference of converter circuits, this paper applied finite element method to analyze a Boost circuit. Transform topology structure of circuit and build corresponding entity finite element modeling. Quantitative analysis for different topology structure electromagnetic distributing and near-field characteristics, and it become clear that the distribution and the role of electromagnetic field of the circuit through the results. The objective of the analysis is to provide the principle and put a new way for the Layout and component design of the power electronic circuits, at the same time above research works make a foundation for further studying EMI problem of the power electronic devices and are of academically and application worthiness.

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