Power Electronics

Power electronics plays an important role in our today society. It is present almost all power supplies, in servo systems and variable drives. The flexible energy conversion of power electronics is also present in energy saving applications and in almost all renewable energy applications, from small photovoltaic to large wind turbines. It is also penetrating our transport means, from railway to electrical bikes, ship propulsion to more performing and electric cars.

Experimental facilities

In EELAB, some instruments are available to support the design and the analysis of power electronic converters, such as calorimeters for efficiency measurements, losses of magnetic materials, a power electronic building blocks for fast prototyping of converters, and a test set-up for the measurement of the converter impedances in a broad frequency range.

Available expertise

  • Inductors and transformers for power electronics
  • Passive components such as inductors and transformers determine for an important part the performance of power electronic circuits. They are a big part of the cost of power electronics. A book has been published on this subject, see below.

  • Converter design and control

    EELAB has been designing and building power electronic converters for a long time, which means that a lot of expertise is available to design or analyse power electronic converters in a wide range of applications: ac-dc converters with power factor correction, high-efficiency dc-dc converters, inverters for motor drives.  For the control of these converters, we have experience with analogue control as well as with digital control.

 

Present Research

  • Grid-connected converters and power factor correction: digital control of ac-dc converters with power factor correction (PFC), dc-ac converters as interface between distributed power generation and the utility grid.
  • High efficiency converters: Our today power electronic converters are already good, but still reduction of losses can be done in switching losses in active components, losses inductors and transformers, losses in the stand by power of power supplies.
  • Brushless dc-drives: Permanent magnet motors do have a fast developing market. The brushless DC drives allow a one-dimensional control of permanent magnet machines. This simplified control has a lot of applications from 1W to 10kW. Special attention has been given to sensorless applications and for higher efficiency drive.
  • Magnetic materials: Work has been done to characterise better soft ferrite materials for waveforms in power electronics. A similar work is busy on characterising nanocrystalline magnetic materials for power electronics. 
  • Energy Saving Applications: In the frame of a Leonardo project, didactical effots are made to improve teaching ways. Especially project based learning and problem based learning. The partners are
    • P1- Transilvania University of Braşov;
    • P2- Ghent University;
    • P3- Paris 7 – Denis Diderot University;
    • P4- Laboratorio delle Idee-Italy;
    • P5- UNNOVA -Development Institute for New Technologies Lisboa;
    • P6- ARCE-Brasov ARCE-Brasov – Romanian Agency for Energy Conservation;
    • P7- Tempus Association for Continuing Education;
    • P8- SC INAR SA - Road Vehicle Institut;
    • P9- IUP Strasbourg     
    • COMPLETE. Pilot Project RO/04/B/F/PP – 175016 http://complete.unitbv.ro/  For example a special application has been made to evaluate stand by losses of electrical boilers.
  • Renewable energy applications:  Renewable energy application have often uncontrolled inputs such as sun, wind, small hydro plants. The task of power electronics is to match the variable voltages and current of the energy source to the application. Activities have been done concerning high efficiency conversion of solar photovoltaic applications,. Today we look at generation electricity from biomass, starting from dry biomass. 
  • Multilevel converters: Multilevel converters offer the possibility to handle larger supply or load voltages that are much higher than the components voltages. It can also improve the compromise between switching losses and reduction of lower harmonics.