26-06-2014, 03:25 PM
POWER ELECTRONICS
POWER ELECTRONICS.ppt (Size: 1.16 MB / Downloads: 31)
Introduction:
- A Cycloconverter is concerned mostly with direct
conversion of energy to a different frequency by
synthesizing a lower-frequency wave from appropriate a
higher-frequency source.
-The basic function of the Cycloconverter is transforming a
high-frequency AC supply to a low-frequency AC supply.
-The Cycloconverter can be used for any low-frequency
applications.
Center-Tap Single-Phase Cycloconverter
A single phase Cycloconverter with center-tap transformer, the load
voltage waveform is constructed on the basis that positive converter (P)
only is conducting for five half cycles, the thyristor being fired without
delay, that is, P is acting as if it were a diode rectifier.
-For the next five half cycles, the negative converter (N) only conducts to
synthesizing the negative half cycle to the load.
-Inspection of the voltage waveform clearly shows an output frequency of
one fifth of the input, the shape tending to a square wave having a large