During the last century, energy production has been supplied, predominantly, by power plants based on fossil fuels. However, for some years the harmful effects on the environment of this source of energy production have caused the awakening of a collective awareness of the need to seek alternative sources for energy generation. In this process, it is renewable energy sources such as solar or wind power that are leading the change. However, the dependence on climatic conditions of these energy sources makes it difficult to achieve a 100% renewable system applicable anywhere on the planet. It is at this point that the need to search for a different and alternative energy source that functions as a central system that complements and completes energy production from renewable sources is born. Nuclear fusion energy emerges in this context as a promising solution that makes it possible to achieve a sustainable society, without the consumption of fossil fuels, the emission of greenhouse gases or highly polluting radioactive waste.

What is fusion energy?

Fusion energy seeks to harness the energy emitted during the fusion of light atomic nuclei. When two such particles merge, the resulting nucleus is slightly lighter than the original ones. The difference, however, does not disappear, but is converted into energy. The truly amazing thing is that this minimal loss of mass translates into a huge amount of energy. This is the reason why there are so many private companies and public entities launched to conquer fusion energy.

To understand a little more the theory of this energy source we have to refer to physics. There are three states of matter: solid, liquid, and gas. But if we keep subjecting a gas to extremely high temperatures, it turns into plasma. In this state, electrons are separated from atoms. When an atom lacks electrons orbiting around the nucleus, it is said to be ionized and is called an ion. Thus, plasma is composed of ions and free electrons. In this state, scientists can stimulate ions to collide with each other, fuse together, and release energy. This is where the creation and operation of the Tokamak comes into play.

What is the Tokamak and how does it work?

Research on nuclear fusion issues is advancing rapidly towards the creation of a commercial and industrial solution that allows the enormous amounts of energy produced by this new and clean energy source to be exploited. One of the most advanced devices is known as the Tokamak, where strong magnetic fields create and confine a plasma in a donut-shaped container where the fusion reaction is achieved.

What is the role of power supplies in all of this?

Power supplies are one of the most important and critical elements of creating a Tokamak. Keeping plasmas stable in order to extract energy is difficult. They are chaotic, extremely hot, and prone to turbulence and other instabilities. Understanding, modeling, and controlling plasma is extremely complex, but researchers have made great strides by using magnetic confinement devices to manipulate plasmas. The magnetic fields are induced by coils, which need to be powered by specific forms of current controlled by their power supplies.

Due to the high currents required in tokamaks, power systems are a demanding part of the design. Most of the relevant tokamaks use thyristor-based and grid-connected or flywheel-based systems, although new trends are leading us towards flexible, modular power supplies based on supercapacitors and Insulated Gate Bipolar Transistors (IGBTs).

Skylife, creators of the power supplies of the Tokamak SMART of the University of Seville

A new Tokamak device for the purpose of fusion energy research, called SMART (SMall Aspect Ratio Tokamak, small aspect ratio tokamak), is being designed at the University of Seville.

Skylife Engineering, in its commitment to sustainability and complex and innovative projects, participates in this project with its line of Power Electronics in charge of the design and manufacture of the magnetic field coils, the microwave system and the power supply system.

The coil system is made up of 3 subsystems, designed to generate and control the flow of plasma inside the vacuum chamber. In total, more than 3000 kg of high conductivity copper will be available.

The 6 kW microwave system operating at 2.45 GHz acts as a booster in the plasma generation process inside the vacuum chamber. The power supply system consists of 5 pieces of equipment to generate a magnetic pulse in the coil system that will form and control the plasma flow in the vacuum chamber.

The electrical pulses will be generated by banks of supercapacitors, with the possibility of being charged with domestic electrical current.

The objective is the installation of a compact spherical tokamak, unique in Spain, which is a world benchmark in the development of magnetic confinement fusion.