Description

Microgrids as one of the main building blocks of the smart grids which facilitate implementation of many smart grid functions and services. It is expected that in a near future, smart grids shall emerge as well-planned plug-and-play integration of microgrids which interact through dedicated highways for exchanging commands, data, and power. Providing a high power quality for the customers is one of the main objectives in smart grids.

On the other hand, the proliferation of different nonlinear and single-phase loads in electrical systems has resulted in voltage harmonic and unbalance as two common power quality problems. In addition, harmonic resonances can be excited giving rise to significant increase of the voltage distortion. These phenomena can cause variety of problems such as protective relays malfunction, overheating of motors and transformers and failure of power factor correction capacitors. 

Day 1: Power Quality in Microgrids, Harmonic Compensation and Virtual Impedance Concept for PQ Improvement

Alexander Micallef (5h), Juan Vasquez (2h)

In this course, measurement, compensation and damping of the main power quality phenomena will be addressed through several control approaches. Both three-phase and single-phase voltage source inverters will be considered. The modelling and control of these power electronic converters are discussed and hierarchical (centralized and decentralized) control approaches are presented in order to enhance the voltage quality. As the synchronization system of power converters plays a key role in their performance in the presence of power quality problems, modelling, designing, and tuning of advanced synchronization systems, including phase-locked loops (PLLs), frequency-locked loops (FLLs), and open-loop synchronization systems, are also discussed. Several simulation exercises will be included in labs which cover about 50% of the course time

Day 2: Synchronization of Power Converters: Introduction, Design and Analysis

Saeed Golestan (6 hours)

The lectures on day 2 are divided into four parts:

1. The first part includes a general description of a standard PLL structure and its modeling, tuning and analyzing its key features, designing advanced PLLs and their modeling and tuning aspects for both single-phase and three-phase systems.
2. The second part includes describing the historical developments of standard single-phase and three-phase FLLs, their modeling and tuning aspects, and extending their structures to deal with power quality problems.
3. The third part includes describing key features of open-loop synchronization systems and presenting two general approaches for designing them.
   The last part includes a brief description of the dynamic interaction between the power converters and its synchronization system, and modeling and analyzing this interaction.

Price

8000 DKK for the Industry and 6000 DKK for PhD students outside of Denmark (VAT-FREE Education)

The Danish universities have entered into an agreement that allows PhD students at a Danish university (except Copenhagen Business School) the opportunity to free of charge take a subject-specific course at another Danish university.
Read more here: https://phdcourses.dk/           

Questions

hr@energy.aau.dk   

More information

https://www.energy.aau.dk/research/phd   

Prerequisites

MATLAB/Simulink SIMPowerSystem knowledge is recommended for the exercises.

Form of evaluation

The participants will be grouped and asked to team work on several case study scenarios and tasks proposed along the course. The assessment in this course will be done through active participation in combination with delivery of exercises reports.

Course literature       

• Micallef, M. Apap, C. S. Staines, and J. M. Guerrero, “Secondary control for reactive power sharing and voltage amplitude restoration in droop‐controlled islanded microgrids,” in 2012 3rd IEEE PEDG, pp. 492‐498, 2012.
• Micallef, M. Apap, C. Spiteri‐Staines, J. M. Guerrero, and J. C. Vasquez, “Reactive Power Sharing and Voltage Harmonic Distortion Compensation of Droop Controlled Single Phase Islanded Microgrids,” IEEE Trans. Smart Grid, vol. 5, no. 3, pp. 1149‐1158, May 2014.
• Micallef, M. Apap, C. Spiteri‐Staines and J. M. Guerrero, “Single‐Phase Microgrid With Seamless Transition Capabilities Between Modes of Operation,” IEEE Trans. Smart Grid, vol. 6, no. 6, pp. 2736‐2745, Oct 2015.
• Micallef, M. Apap, C. Spiteri‐Staines and J. M. Guerrero, “Mitigation of Harmonics in Grid‐ Connected and Islanded Microgrids via Virtual Admittances and Impedances', IEEE Trans. Smart Grid. 2018
• Micallef, “A Review of the Current Challenges and Methods to Mitigate Power Quality Issues in Single‐Phase Microgrids”, IET Generation Transmission & Distribution,2018.
• R. Tonkoski et al., “Coordinated Active Power Curtailment of Grid Connected PV Inverters for Overvoltage Prevention”, IEEE Trans. Sustainable Energy, vol. 2, no. 2, Apr. 2011
• Hui et al., “Electric Springs ‐ A New Smart Grid Technology”, IEEE Trans. Smart Grid, vol. 3, no. 3, pp. 1552‐1561, Sept. 2012
• Micallef and C. Spiteri‐Staines, “Voltage rise mitigation and low voltage ride through capabilities for grid‐connected low voltage microgrids”, 19th European Conf. on Power Electr. and App. (EPE'17), 2017

General understanding of PLLs and their state of the art

• S. Golestan, J. M. Guerrero and J. C. Vasquez, "Three-Phase PLLs: A Review of Recent Advances," in IEEE Transactions on Power Electronics, vol. 32, no. 3, pp. 1894-1907, March 2017, doi: 10.1109/TPEL.2016.2565642.
• S. Golestan, J. M. Guerrero and J. C. Vasquez, "Single-Phase PLLs: A Review of Recent Advances," in IEEE Transactions on Power Electronics, vol. 32, no. 12, pp. 9013-9030, Dec. 2017, doi: 10.1109/TPEL.2017.2653861.

General understanding of FLLs and their state of the art

• S. Golestan, J. M. Guerrero, J. C. Vasquez, A. M. Abusorrah and Y. Al-Turki, "A Study on Three-Phase FLLs," in IEEE Transactions on Power Electronics, vol. 34, no. 1, pp. 213-224, Jan. 2019, doi: 10.1109/TPEL.2018.2826068.
• S. Golestan, J. M. Guerrero, F. Musavi and J. C. Vasquez, "Single-Phase Frequency-Locked Loops: A Comprehensive Review," in IEEE Transactions on Power Electronics, vol. 34, no. 12, pp. 11791-11812, Dec. 2019, doi: 10.1109/TPEL.2019.2910247.

Open‐loop synchronization systems and their state of the art

• S. Golestan, J. M. Guerrero, Y. Al-Turki, A. M. Abusorrah and J. C. Vasquez, "Open-Loop Synchronization Systems for Grid-Tied Power Converters: Literature Overview, Design Considerations, Advantages, and Disadvantages," in IEEE Industrial Electronics Magazine, doi: 10.1109/MIE.2021.3126255.
• S. Golestan, A. Vidal, A. G. Yepes, J. M. Guerrero, J. C. Vasquez and J. Doval-Gandoy, "A True Open-Loop Synchronization Technique," in IEEE Transactions on Industrial Informatics, vol. 12, no. 3, pp. 1093-1103, June 2016, doi: 10.1109/TII.2016.2550017.
• S. Golestan, J. M. Guerrero and J. C. Vasquez, "An Open-Loop Grid Synchronization Approach for Single- Phase Applications," in IEEE Transactions on Power Electronics, vol. 33, no. 7, pp. 5548-5555, July 2018, doi: 10.1109/TPEL.2017.2782622.

Modeling, Analyzing, and Designing Synchronization Techniques for Power Converters

• S. Golestan, A. Akhavan, J. M. Guerrero, A. M. Abusorrah, M. J. H. Rawa and J. C. Vasquez, "In-Loop Filters and Prefilters in Phase-Locked Loop Systems: Equivalent or Different Solutions?," in IEEE Industrial Electronics Magazine, doi: 10.1109/MIE.2021.3121652.
• D. Dong, B. Wen, D. Boroyevich, P. Mattavelli and Y. Xue, "Analysis of Phase-Locked Loop Low-Frequency Stability in Three-Phase Grid-Connected Power Converters Considering Impedance Interactions," in IEEE Transactions on Industrial Electronics, vol. 62, no. 1, pp. 310-321, Jan. 2015, doi:  0.1109/TIE.2014.2334665.

Laboratory introduction handbook (provided via Moodle)