Stanimir VALTCHEV
Professor in University NOVA of Lisbon, PORTUGAL, Invited Full Professor in Burgas Free University (since 2012) and the Technical University of Sofia, BULGARIA (since 2018)
Research interests:
power converters, energy harvesting, wireless energy transfer, electric vehicles, energy management and storage, non-destructive testing, bio energy-harvesting, and biosensors
Keynote address:
Renewable Energy Invasion Requires Both DC Grid and Wireless Energy Transfer
Abstract:
The traditional world-wide power system is based on AC energy, having to fight the consequences, e.g. the synchronisation, the reactive power, etc. Then came, the renewable energies, as already possible, and even, unavoidably necessitated, and made everything more complicated. The generators of 2-4 kW each, to supply blocks in the Data centre, where each block is 50 times more powerful than each of the generators. The invasion of the renewable energy made more difficult that classic fight for synchronous power flow, but the renewable energy sources have one useful characteristic: they are mostly DC, or easily transferable into a DC power supply. The invasion of the renewable energies made more realistic the dream of Thomas Edison, a DC grid, which has no need of synchronisation, neither has reactive power problems. The Low Voltage (LV) DC grid is prepared to be a Smart Grid, even reaching now 800 V or more, as the efficiency is pushing the competition into highest operational voltages. The EU regulations permit the LV to be extended even up to 1500 V, which permits much higher efficiency. At this point although, start the problems of the dangerously high levels of the DC voltage. In the same time, it can be proved that the DC-DC conversion is always using the magnetic field as a power link, and that magnetic coupling is going into all the time higher frequency of operation. In fact, the link in most of the power converters is magnetic. Then the wireless energy transfer is also magnetically linked. The difference between the “normal” and the wireless DC-DC converter is only the percentage of the magnetic coupling. The magnetic field connections of the renewable energy sources will be more reliable and less dangerous for the human beings and the animals. They do not need cleaning of the contacts, as they are easily connectable even by low experience workers and clients.
Stanimir VALTCHEV was born in Bulgaria in 1951. Best graduate in 1974 of Technical University Sofia (TUS), semiconductor and electronics technology, Auxiliary Director of the Centre of Robotics of TUS. In 1987 worked in TU Delft as assistant professor and assistant professor in TUS (Power Supplies and Converters), Vice Dean of TUS for all international students. Now teaching Power Electronics and Instrumentation in the University Nova of Lisbon, Portugal, Invited Professor of Burgas Free University and TUS, Bulgaria. Since 1994 teaching and consulting in Portugal, Netherlands and China. Based on a versatile experience, the research includes HF resonant power converters, energy harvesting, wireless energy transfer, electric vehicles, energy management and storage, smart DC grids, tunnel FET devices and biosensors. He was the General Chair of the IEEE-PEMC2016 conference and Chair of Subcommittee in IES of IEEE. He is on the advisory boards in prestigious universities in Russia and China, honorary chair of conference SUMMA (Russia), co-chair of conference GPECOM (Turkey).
