The Highly Efficient And Reliable smart Transformer (HEART)

What is HEART?

In the last 10 years, power electronics has moved significantly towards the electric grid, making it more flexible and decentralized. Still important challenges remain. One of the most thrilling is re-inventing the distribution transformer after more than 125 years since its first use in the electrification of a city. In fact, actual distribution transformers can no longer fulfill the requirements of a modern electric grid highly dominated by distributed sources and new sizable loads, like heat pumps and electric vehicles.

This project proposes the invention of a novel "Smart Transformer" (ST), based on a modular architecture of units made by power electronics converters, that will be able to manage the energy and the information flows among sources and loads in the distribution area with the goal of decoupling it from the rest of the bulk power system. Actual proposals of Smart Transformers cannot compete in terms of cost, efficiency and reliability with traditional transformers.

This project has decided to take this challenge with a paradigm shift in how to approach it and a new set of methodologies. The breakthrough results of this research will be obtained taking the following high-risk high-gain bet: significantly influence the efficiency and the reliability of the Smart Transformer by routing the energy flows among its power converter units, and inside them among the power modules. A new understanding of how the energy flows are managed by the modular connection of power converter units will guide the design of new architectures for the ST allowing different routes for the energy. Graph theory will be used to find optimal paths for the energy flows with the goal of maximizing efficiency and reliability by minimizing ageing of power modules, controlling the chip temperature inside the power modules. The energy flows will be managed akin to Internet switched packet data by relying on information enclosed in packet headers. The controller of the ST will switch "packets of energy" by taking into account the information traveling on the communication system and coming from the electric distribution system sensors (requirements) and from the power module sensors (constraints).

The holy grail of this research is to provide a new durable heart to the electric distribution system. The impact of the research will be twofold: at the system level and at the component level.

At the system level: the Smart Transformer will provide a seamless linking between the past power system (centralized) and the new one (de-centralized), increasing the reliability and hosting capacity of the electric distribution grid, especially for renewable energy systems and electric vehicles charging stations.

 At the component level: the developed design methods will be valid in the entire, growing field of high-power electronics especially for those applications highly demanding in terms of stressing working conditions and safety requirements; the developed control techniques will have also wider application in power electronics that is dominated now by dynamics and stability problems but in the future will request actions tailored at reducing losses, extending the lifetime and reducing the need of oversizing, now very common in the aforementioned highly demanding applications. Finally, this project success will be also largely measured in terms of its providing the sensing solutions, the advanced drivers for power semiconductors and communication technologies to enable the advanced control strategies previously mentioned. 

Chair of Power Electronics

  • Chair of Power Electronics, CAU Kiel