The Highly Efficient And Reliable smart Transformer (HEART)


The aim of this project is to propose a paradigm shift in the design of the Smart Transformer focusing on a new and holistic research approach covering the full span of power electronics, control, advanced sensing and communication in order to cope with high reliability and high efficiency requirements of distribution transformers, while preserving the advanced features at the system level.

The research hypothesis is

Increase the efficiency and the reliability of the Smart Transformer by routing its internal energy flows.

The goal is to obtain a new “Heart” for the distribution system that regulates the energy flows among its units and the high-frequency magnetics and capacitors, and where the units manage the share of the energy flows among their modules (Fig. 2).

The more specific objectives are

-          Develop theory, models and methods to design the architecture of the ST as an energy flow controller that activates energy paths depending on the power system requirements (critical loads, EVs, renewable production) and on the constraints on power components (switching devices and passive elements).

-            Create a theoretical basis and a hardware platform to investigate control methods with focus on temperature (maximum, average and excursion) enabling smart use of the ST architecture targeting low losses and lifetime extension.

-          Develop sensors, advanced drivers and communication solutions to monitor and control the health of the ST and actuate the routing of energy flows.


Figure 2. The Smart Transformer and its power flows through units, made by power modules and connected through passive elements - Medium voltage (MV), Low Voltage (LV), Alternate Current (AC), Direct Current (DC).

The results necessary for obtaining these objectives will be groundbreaking in electrical engineering through the following outcomes:

-          New design methods for high-power electronics systems, conceived with a modular approach, for smart grid technologies and renewable energies, which shall take full advantage of the currently most advanced sensing and communication solutions.

-          New control methods and hardware solutions to reduce overall losses and thermal excursion of the power semiconductors within the power modules.

-          New useful sensors, actuators and communication solutions for enabling a new category of control techniques directly acting on the core of the power module.

The design methods will be valid not only for the Smart Transformer but in the entire, growing field of high-power electronics, especially smart grid and renewable energies, and for those highly demanding applications in terms of stressing working conditions and high safety requirements. The control methods will also have wider application in power electronics which is now dominated by dynamics and stability problems but in the future will require actions tailored to reducing losses, extending lifetime and reducing the need for oversizing, now very common in wind energy and in the aforementioned highly demanding applications. Finally, this project’s success will also be measured in terms of its providing the sensing solutions and new advanced drivers for power semiconductors developed with particular focus on their communication capabilities to enable the advanced control strategies previously mentioned. It is planned that the results and tools will be available on a website for “Heart”.

Chair of Power Electronics

  • Chair of Power Electronics, CAU Kiel