Fraunhofer ISE researchers win innovation award

Researchers from the Fraunhofer Institute for Solar Energy Systems in Freiburg, Germany, have won this year’s Semikron Innovation Award for the development of off-grid solar energy supply systems technology that could be especially beneficial to villages and businesses in emerging countries.

The award went to the team of Fraunhofer ISE researchers Michael Eberlin, Florian Reiners, Olivier Stalter and Sebastian Franz as well as Frank Seybold of German group Kaco New Energy for their "Innovative power electronics for the next generation village energy supply" concept, the Fraunhofer ISE announced on Friday.

The award honors the development of power electronics components for the next generation solar energy systems. The technology developed by the researchers allows a maximum amount of renewable energies being integrated into isolated power grids.

“The researchers from the power electronics department at the Fraunhofer ISE in Freiburg and at Kaco New Energy have developed power electronics components for a complete off-grid solar energy supply system,” said Bettina Heidenreich-Martin, member of the Semikron Foundation Board. “The innovation is considered a holistic approach to off-grid PV supply for larger consumers, such as villages and businesses, particularly in emerging countries.”

Stalter, who headed the project, said, “1.6 billion people in the world have no access to electricity. Since most of these countries are in the earth’s sun belt, solar power is a simple solution that has become even more attractive by the cost reductions for photovoltaic modules. Up until now, these solar systems were mostly limited to small capacity of about 100 watts. Our system transfers the latest technologies of the industrialized nations to meet the needs of local communities and larger consumers, such as hospitals and smaller industrial companies."

The components developed at the Fraunhofer ISE consist mainly of a grid inverter with an output of 125 kW and a charger with an output of 51 kW for battery voltages up to 1,000 V. The basic idea was to use the latest semiconductor devices such as Superjunction MOS-FETs and SiC diodes to design a system for high voltage and high internal switching frequencies, allowing for low currents, low losses and reduced component sizes, cooling requirements, material usage and costs. At the same time, losses over conventional devices can be reduced by up to 60%. The inverter operates at up to 98% efficiency, the charger at 99%.

The technology had to be simple, particularly for developing countries. A single unit suffices now, compared to the many units connected in parallel with lots of cable and circuitry that was necessary for high performance up until now. High-tech components and fully digital control also allow maximum flexibility. As a result, 350-1,200 V photovoltaic systems and 650-1,000 V battery systems can be used with nominal voltage.

The award, which is bestowed by the Semikron Foundation and the European Centre for Power Electronics e.V. (ECPE), is endowed with €10,000 ($13,216).