7/21/2019 Diode Failure Tlittler

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7/21/2019 Diode Failure Tlittler

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The design of the exciter – rectifier system must allow for a range of operating conditions, including; sudden loadchange, load short-circuit, unbalanced phase loading, rectifier failure, field winding faults, and synchronism slacking ortotal loss. Rectifier diodes must be chosen to take account of all conditions. A means of assessing the operatingcondition of the rectifier-bridge diodes is important and, although not directly measurable, is achievable by non-invasivemonitoring of the exciter field, using a current transformer (CT).

This project will build on work developed in previous final year projects. The project will implement a real-timetechnique for bridge rectifier diode failure in a brushless alternator.

The objectives of this project are to:

1.  Understand the operation of the brushless alternator.2.  Acquire field excitation signals from a lab alternator for different load and fault conditions (single-diode

failure).3.  Examine abnormal excitation signals using wavelet analysis (and apply Fourier analysis to extract the failure

‘signature’).4.  Develop real-time (rapid) detection of diode failure using a wavelet method.5.  Evaluate real-time detection using a lab-alternator under different load and fault conditions (for single diode

failure).

MEng Extensions

1.  Determine the effect of multiple diode failure and methods of discriminating failure signatures from normalload conditions.

2.  Develop an algorithm to detect single and multiple diode failure under specified conditions.

As this is predominantly a software project, a student undertaking the project should be confident in the use ofcomputer programming languages, including C/C++ and Matlab M scripts.