CYCLOCONVETERS BY Dr S NARASIMHA CYCLOCONVERTER A Device

CYCLOCONVETERS BY: Dr. S. NARASIMHA

CYCLOCONVERTER � A Device which converts input power at one frequency to output power at a different frequency with onestage conversion. � AC to AC conversion � Developed in 1930 , GERMANY � Uses SCR (THYRISTORS) � Force commutation

CONTENTS � INTRODUCTION � TYPES � PRINCIPLE � SINGLE PHASE CYCLOCONVETER � THREE PHASE CYCLOCONVERTER

TYPES � Step up cycloconverter ( Fo>Fs ) � Step down cycloconverter( Fo<Fs ) � Single phase to single phase �Mid-point cycloconverter �Bridge type cycloconverter � Three phase cycloconverter

SINGLE PHASE CYCLOCONVETER � Step up Cycloconverter: - �LOW Frequency to HIGH Frequency � Step down Cycloconverter: - �HIGH Frequency to LOW Frequency

STEP-UP CYCLONVERTER � LOW TO HIGH FREQUENCY CONVERTER � MID-POINT CYCLOCONVERTER � BRIDGE TYPE CYCLOCONVERTER

MID-POINT CYCLONVERTER

BRIDGE TYPE CYCLONVERTER

STEP-DOWN CYCLONVERTER � HIGH TO LOW FREQUENCY CONVERTER � MID POINT CYCLOCONVERTER � BRIDGE TYPE CYCLOCONVERTER

MID-POINT CYCLONVERTER

BRIDGE TYPE CYCLONVERTER

THREE PHASE CYCLOCONVERTER � THREE PHASE TO SINGLE PHASE � THREE PHASE TO THREE PHASE

THREE PHASE TO SINGLE PHASE

THREE PHASE TO THREE PHASE

FEATURES ADVANTAGES DIS-ADVANTAGES � Direct conversion � Large number of thyristors � Compact system � Complex circuitry � Variable speed range � Output frequency is limited � High quality wave � Low speed applications

APPLICATIONS � SPEED CONTROL DRIVES � INDUCTION HEATING � VARIABLE FREQUENCY INPUT AND GETTING CONSTANT OUTPUT

Applications of Cycloconverters: • Cycloconverters can produce harmonic rich output voltages. • When cycloconverters are using for a running AC machine, the leakage inductance of the machine filters most of the high frequency harmonics and reducing voltage of the lower order harmonics.

Controlling the Speed of the Single Phase Induction Motor Some other applications where Cycloconverters can be used are cement mill drives, ship propulsion drives, Rolling mills, and mine winders, washing machines, water pumps and used in industries as well.

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