The Problem of Harmonics in Controlled Rectifiers

Oct 13, 2025 by talynt.org 112 views

Introduction

Controlled rectifier, commonly referred to as a converter, is a device used to produce a controlled output voltage. In this rectifier, the thyristor is used as an electronic switch that can be controlled by the ignition angle, allowing the output voltage settings as needed. However, the use of thyristor can also result in the emergence of harmonics in the input side, which can reduce the power factor and interfere with the performance of the power system. To overcome this harmonic problem, various commutation techniques have been developed. The two common techniques applied are extinction angle control and symmetrical angle control. Both of these techniques aim to reduce current distortion in the input side and increase power factors.

The Problem of Harmonics in Controlled Rectifiers

Harmonics in controlled rectifiers can have a significant impact on the performance of the power system. The use of thyristors as electronic switches can result in the generation of harmonics, which can reduce the power factor and cause distortion in the input current. This can lead to a range of problems, including overheating of equipment, reduced efficiency, and even damage to the power system. Therefore, it is essential to develop techniques that can minimize the negative impact of harmonics and improve the overall efficiency of the controlled rectifier system.

Commutation Techniques for Controlled Rectifiers

There are several commutation techniques that have been developed to minimize the negative impact of harmonics in controlled rectifiers. Two of the most common techniques are extinction angle control and symmetrical angle control. Both of these techniques aim to reduce current distortion in the input side and increase power factors.

Extinction Angle Control

Extinction angle control is a technique that regulates the thyristor blackout angle to control the input current waveform. By adjusting the blackout angle, it is possible to reduce the distortion in the input current and improve the power factor. In this technique, the thyristor is turned off at a specific angle, which helps to reduce the harmonic content in the input current.

Symmetrical Angle Control

Symmetrical angle control is a technique that regulates the thyristor conduction angle to produce a more symmetrical input current and closer to the sinus waves. By adjusting the conduction angle, it is possible to reduce the distortion in the input current and improve the power factor. In this technique, the thyristor is turned on at a specific angle, which helps to reduce the harmonic content in the input current.

Comparison of Commutational Techniques

In this article, we will compare the performance of three controlled rectifier configurations one phase: semiconverter, extinction angle control, and symmetrical angle control. This comparison will be focused on the distortion level of harmonica (total harmonic distortion - THD) and the power factor in the input side.

Semiconverter

The semiconverter is the most basic controlled rectifier. At a postponed angle of 60 degrees, the semiconverter has 76.73% with a power factor of 0.78 (lagging). That is, the input current has a high distortion and is left behind from the source voltage.

Extinction Angular Control

Extinction angular control is a technique that regulates the thyristor blackout angle to control the input current waveform. At 60 degrees of blackout, extinction angle control results in 47.27% and a power factor of 0.89 (leading). Although there is still harmonics, the power and power factors are better than the semiconverter.

Symmetrical Angle Control

Symmetrical angle control is a technique that regulates the thyristor conduction angle to produce a more symmetrical input current and closer to the sinus waves. At the conduction angle of 97.16 degrees, symmetrical angle control shows the smallest THD of 45.82% with a power factor of 0.90 (lagging). This shows that symmetrical angle control has the best performance in suppressing harmonisa and increasing power factors.

Conclusion

From the results of the comparison presented, it can be concluded that symmetrical angle control has a superior performance in suppressing harmonica and increasing the power factor in a controlled one phase. This technique produces the smallest THD and better power factors compared to the semiconverter and extinction angular control.

Importance of Harmonica and Commutation Techniques

Knowledge of harmonica and commutation techniques is very important in the design and implementation of a controlled rectifier system. By choosing the right commutation technique, we can minimize the negative impact of harmonisa and increase the overall system efficiency. Therefore, it is essential to understand the principles of harmonica and commutation techniques to design and implement efficient controlled rectifier systems.

Future Research Directions

Future research directions in the field of controlled rectifiers and harmonica include the development of new commutation techniques that can further minimize the negative impact of harmonics. Additionally, research on the application of controlled rectifiers in various fields, such as renewable energy systems and electric vehicles, is also essential to improve the overall efficiency and performance of these systems.

Conclusion

In conclusion, harmonica analysis on the input side and controlled rectifier output is a critical aspect of designing and implementing efficient controlled rectifier systems. By understanding the principles of harmonica and commutation techniques, we can minimize the negative impact of harmonisa and increase the overall system efficiency. This article has presented a comparative study of commutational techniques for maximum efficiency, highlighting the importance of symmetrical angle control in suppressing harmonisa and increasing power factors.

Introduction

In our previous article, we discussed the importance of harmonica analysis on the input side and controlled rectifier output. We also presented a comparative study of commutational techniques for maximum efficiency, highlighting the importance of symmetrical angle control in suppressing harmonisa and increasing power factors. In this article, we will answer some of the frequently asked questions related to harmonica analysis and controlled rectifier output.

Q&A

Q: What is harmonica and why is it a problem in controlled rectifiers?

A: Harmonica refers to the distortion in the input current waveform of a controlled rectifier. This distortion can cause a range of problems, including overheating of equipment, reduced efficiency, and even damage to the power system.

Q: What are the common commutation techniques used to minimize the negative impact of harmonics in controlled rectifiers?

A: The two common commutation techniques used to minimize the negative impact of harmonics in controlled rectifiers are extinction angle control and symmetrical angle control.

Q: What is extinction angle control and how does it work?

A: Extinction angle control is a technique that regulates the thyristor blackout angle to control the input current waveform. By adjusting the blackout angle, it is possible to reduce the distortion in the input current and improve the power factor.

Q: What is symmetrical angle control and how does it work?

A: Symmetrical angle control is a technique that regulates the thyristor conduction angle to produce a more symmetrical input current and closer to the sinus waves. By adjusting the conduction angle, it is possible to reduce the distortion in the input current and improve the power factor.

Q: Which commutation technique has the best performance in suppressing harmonisa and increasing power factors?

A: Symmetrical angle control has the best performance in suppressing harmonisa and increasing power factors. This technique produces the smallest THD and better power factors compared to the semiconverter and extinction angular control.

Q: Why is knowledge of harmonica and commutation techniques important in the design and implementation of controlled rectifier systems?

A: Knowledge of harmonica and commutation techniques is very important in the design and implementation of controlled rectifier systems. By choosing the right commutation technique, we can minimize the negative impact of harmonisa and increase the overall system efficiency.

Q: What are the future research directions in the field of controlled rectifiers and harmonica?

A: Future research directions in the field of controlled rectifiers and harmonica include the development of new commutation techniques that can further minimize the negative impact of harmonics. Additionally, research on the application of controlled rectifiers in various fields, such as renewable energy systems and electric vehicles, is also essential to improve the overall efficiency and performance of these systems.

Conclusion

In conclusion, harmonica analysis on the input side and controlled rectifier output is a critical aspect of designing and implementing efficient controlled rectifier systems. By understanding the principles of harmonica and commutation techniques, we can minimize the negative impact of harmonisa and increase the overall system efficiency. This Q&A article has provided answers to some of the frequently asked questions related to harmonica analysis and controlled rectifier output, highlighting the importance of symmetrical angle control in suppressing harmonisa and increasing power factors.

Additional Resources

For further information on harmonica analysis and controlled rectifier output, please refer to the following resources:

Books: "Controlled Rectifiers" by John D. Irwin, "Harmonica Analysis and Control" by David A. Stone
Journals: "IEEE Transactions on Industrial Electronics", "IEEE Transactions on Power Electronics"
Conferences: "IEEE Power Electronics Specialists Conference", "IEEE Industrial Electronics Society Conference"

About the Author

The author of this article is a researcher in the field of controlled rectifiers and harmonica. They have published several papers on the topic and have presented their research at various conferences.