Advantages and disadvantages of cycloconverter

Cycloconverter is actually AC-AC converter. It converts a constant voltage and constant frequency AC waveform to another AC waveform. This article gives information about some advantages and disadvantages of cyclo-converter to know more details about cyclo-converter. 

Advantages of cyclo-converter :

• Efficiency is very high compared to other converters
• Four quadrant operation is possible because cyclo-converter is capable of power transfer in both the directions
• AC power at one frequency is directly converted to a lower frequency in a single conversion
• If one of the SCR fails, the cyclo-converter operates with a distorted output
• In this converter, power transfer is possible from supply load and vice versa at any power factor
• Dynamic response is good 
• Smooth low-speed operation

Disadvantages of cyclo-converter :

• Control circuit become complex so difficult to design
• The output frequency of the cyclo-converter is 1/3th or 1/2th for responsible power output and efficiency
• Power factor is too much poor at large values of α
• More distortion at low frequencies

Explore more information:

1. What are the advantages of cyclo converter over the inverter
2. What are the applications of cycloconverter
3. What are the operation of cycloconverter

Application of cycloconverter

Cyclo-converter is basically converted input power at one frequency to output power at a different frequency with one stage of conversion.

Basically, cyclo-converter is two types namely :  

• Step down cyclo-converters
• Step-up cyclo-converters

The application of cyclo-converters include the following :

• Speed control of high power ac drives.
• Static VAr compensation.
• Induction heating.
• Synchronous motor.
• Rolling mill drives.
• Mine winders.
• Cement mill drives.
• This converter also has used for converting variable speed alternator to constant frequency output with age for use as a power supply in aircraft or shipboards.
• HVDC transmission system.
• Grinding mills.

Explore more information:

1. Advantages and disadvantages of cycloconverter

Cycloconverter operation

A principle of cyclo-converter operation :

• A cyclo-converter is a one types of device that converts AC power at a certain frequency into AC power but lower frequency.

• The principle of cyclo-converter is described given below by using a single phase to single phase step-up converters and single phase to single phase step down converters.

Cyclo-converter operation

Types of cyclo-converter :

1. Single phase to single phase cyclo-converter 
2. Three phases to three phase cyclo-converter 

Single phase to single phase bridge type cyclo-converter 

• The operation of bridge type cyclo-converter shown in the figure. It can be easily explained for both discontinuous and continuous load current. The voltage and current waveform would again be as shown in the figure. 
• It consists of a total of eight thyristors, four for the positive group and four for the negative group. 

Bridge type single phase to single phase cyclo-converters

This converter having to back to back connection of full wave rectifier. We have to assume that get on forth of the input voltage as the output.  For the first two cycles of  VS the positive converters operate supplying current to the load and the input voltage get rectified. In the next two cycles, the other converter called the -ve converters, it will operate the current load in the opposite direction called a reverse direction. so we also conclude that one converter is an operation the other converter will be disabled conditions, therefore, there is no current circulating between rectifiers.

Three phases to three phase cyclo-converters 

Out of the several configurations of 3 phase to 3 phase cyclo-configuration as shown in the figure. Here only one important scheme used for a large industrial drive is presented. Each phase of the 3 phase output must have a displacement of 120 degrees. The figure shows the circuit arrangement of 3-phase to three phase cyclo-converter using three sets of three-phase half wave circuit employing a total of 18 thyristors. 

3-phase to 3-phase cyclo-converters

Applications :

The application of cyclo-converters include the following :

• Speed control of high power ac drives.
• Static VAr compensation.
• Induction heating.
• Synchronous motor.
• Rolling mill drives.
• Mine winders.
• Cement mill drives.
• For converting variable speed alternator to constant frequency output with age for use as a power supply in aircraft or shipboards.
• HVDC transmission system.
• Grinding mills.