Innovative methods will give stability to the electrical system with the use of renewable sources

Investigación, which has funding from the Fondecyt Regular 2023 contest, will develop modular multilevel systems, which is expected to contribute towards a green matrix in Chile.

One of the problems with the injection of renewable energy into the electrical system is the potential risk of generating instability in the energy matrix: if the sun goes down or the wind stops blowing, the photovoltaic or wind systems lose their generation capacity, generating intermittency in the supply.

The way to respond to this is through storage systems that allow for constant energy from renewable sources. However, it is not a solved problem, which makes having a 100% green energy matrix a difficult task to carry out.

This problem is the one that the academic of the Faculty of Engineering from UCSC, Dr. Ricardo Lizana, in the “Hybrid Energy Storage Systems based on Multi-Module Power Topologies” project, which was awarded the Fondecyt Regular 2023 contest.

“It consists of addressing the problem of the systems that allow the interconnection of complementary services to the electricity grid. The complementary services are those that give stability to the network under certain disturbances, to ensure that the electrical system remains stable and does not occur, in critical situations, blackouts or blackout. When the electrical network has a lot of energy injected from renewable energy sources, the variations typical of this type of energy produce instability, so complementary services are key”, stated the researcher.

To provide a structure of complementary services, storage units are needed. That stored energy is then injected into the grid to keep the electrical system as stable as possible against disturbances that occur when renewable energy is connected. As explained by the academic, traditionally the energy stored is in large battery units or green hydrogen cells. If the storage unit fails, the entire system collapses and the ability to generate complementary services to the electricity grid is lost.

“What this project proposes is a system called ‘modular multilevel’, where each power electronics module has a storage system interconnected that can be different. For example, one connected to a battery, another to a hydrogen fuel cell, another to a supercapacitor, and that everything be integrated into a great system, that works in a heterogeneous way, but at the same time harmoniously. This distribution, with different storage sources, gives the equipment more flexibility, but, in addition, they are smaller units, so if one of them fails, it is easier to replace it and continue operating”, explained Dr. Ricardo Lizana.

border knowledge

“The novelty of the project is that the storage systems are heterogeneous, that is, they are different from one another, but from the point of view of the connection to the network they behave as a homogeneous unit, as a whole. It is a system that could have a high density, both energy and power. If it is done with a storage system with a single technology, it loses the ability to include different characteristics of other storage systems, such as dynamic responses, high current operation capacity, among others. On the other hand, in this proposal, when considering heterogeneous storage units, a system is obtained that can have multiple characteristics, which are provided by the different storage units”, added an academic from the Faculty of Engineering.

In this way, the initiative hopes to contribute to knowledge in frontier science and technology for this new type of systems, as well as to validate it, achieve new control methods, design topologies, have experimental results and generate publications in highly prestigious journals on the subject. of power electronics.

For Dr. Ricardo Lizana, “this work is significant because one of the lines that we define with the FNDR project of the hydrogen production plant (which was awarded to UCSC in 2021) is the use of green hydrogen for applications in the system electric. Now, with this Fondecyt 2023 project, the use of green hydrogen fuel cells is addressed to provide complementary services to the electricity grid, thus connecting the different initiatives of the University”.