Lesson 1 Chapter Four
Effect of Source Inductance on the Performance of AC to DC Converters
Instructional Objectives
On completion the student will be able to
• Draw the voltage and current waveforms associated with a converter taking into account the effect of source inductance.
• Find the average output voltage of the converter as a function of the firing angle and overlap angle.
• Estimate overlap angles under a given operating condition and hence determine the turn off time available for the thyristors.
• Draw the dc equivalent circuit of a converter and parameterize it.
• Find out the voltage stress on the thyristors due to commutation overlap.
Introduction
In the previous lessons the input ac power sources supplying an ac to dc power converter have been assumed to be ideal with no source impedance. Although this assumption simplifies the analysis of the converters, in most practical situations, they are not fully justified. Most ac dc converters are supplied from transformers. The series impedance of the transformer can not always be neglected. Even if no transformer is used, the impedance of the feeder line comes in series with the source. In most cases this impedance is predominantly inductive with negligible resistive component. The presence of source inductance does have significant effect on the performance of the converter. With source inductance present the output voltage of a converter does not remain constant for a given firing angle. Instead it drops gradually with load current. The converter output voltage and input current waveforms also change significantly. In this lesson a quantitative analysis of these effects will be taken up in some detail.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .