20.

F. Bertling and S. Soter, "Improving grid voltage quality by decentral injection of current harmonics" in IECON 2005 - 31th Annual Conference of the IEEE Industrial Electronics Society, 2005, pp. 3 pp.

Abstract:
This research project deals with the development of an adjustable converter for injection of fuel cell power. A DC/DC converter stage increasing the voltage level is connected to a DC/AC inverter for grid current injection via a high capacitance DC link. This decouples the momentary power drawn from the energy source from the momentary power being injected into the grid, allowing arbitrary output current waveforms without an increase of input current ripple. Conventionally, pure fundamental frequency currents are considered the optimum waveform regarding the injected currents impact on the grid. This paper demonstrates how grid voltage harmonics caused by nonlinear loads can be minimized by adapting the converters injected current shape. In contrast to harmonics compensation in industrial applications where the compensation current is determined by measuring the local loads current harmonics, the intended decentral application in private houses suggests a different approach to improve overall grid voltage quality. The digital signal processor used for the converters control and monitoring functions calculates the frequency spectrum of the measured grid voltage run by digital Fourier transformation (DFT) and determines the current harmonics necessary to counteract the present voltage harmonics. The resulting current frequency spectrum is modulated into a time dependant current shape that is added to the fundamental frequency current run determined by the requested amounts of active and reactive power. This way, harmonic currents of the local loads are compensated without changes in the house installation for measuring the loads currents. Also current harmonics of neighbouring houses are compensated.

19.

R. Lach and S. Soter, "Measuring method for determining the reasons of magnetically caused structure-borne sound on electrical drive systems" in 2005 European Conference on Power Electronics and Applications, 2005, pp. 10 pp--P.10.

Abstract:
A special signal processing method (order analysis) allows well-defined conclusions from accelerometer measurements on electrical drives regarding the reasons of structure-borne and airborne sound. In this paper an analysis of acceleration signals of an 5 kW induction machine is presented. The special feature is that a projection of sound curves is included in this analysis. Thus it is possible to assign an oscillation excitation to harmonics attributed to the machine design or harmonics of the feeding frequency converter.

18.

A. Wirsen and S. Soter, "Berührungslose Drehmomenterfassung - Turbosätze altern unter strengeer Beobachtung", SENSOR report, vol. 2004, no. 4, 2004.

17.

S. Soter and R. Lach, "Von der Sonne zur eigenen Photovaltaik-Anlage: Verbraucher-Informationen im Internet" in 19. Symposium Photovoltaische Solarenergie, 2004.

16.

S. Soter and F. Bertling, "Adjustable converter for injection of fuel cell power as a part of a virtual power plant" in PESC04, Piscataway, N.J: IEEE, 2004, pp. 1988-1990 Vol.3.

Abstract:
This research project deals with the development of a solid, intelligent converter with a good value. The energy of fuel cells or other low-voltage energy-sources (40 to 80 VDC) is feeded decentral into the public net (230 VAC/50 Hz or 110 VAC/60 Hz). Because of the requirements of the serial product (e.g. low price, reliability, range of use) a prototype of a converter with high frequency transformer was built. The latest electronic devices and a digital signal processor as central controller have been applied to achieve high efficiency and flexible power injection. It is possible to obtain improvements of the local voltage quality and stability by adjusting active and reactive power as well as power factor and current shape.

15.

R. Lach, S. Soter and R. Wegener, "Experimental determination of systemeigenfrequencies on electrical drives" in 11th International Power Electronics and Motion Control Conference, Riga: {Riga Technical University}, 2004.

14.

R. Lach and S. Soter, "Individual Approach to an Efficient Minimization of Vibration an Noise Stimulation for Inverter-Fed Drives" in PCIM Asia 2004, 2004.

13.

R. Lach and S. Soter, "Sound source location measuring system for a systematic design modification of electrical machines" in PCIM Europe, 2004.

12.

S. Soter, "Windkraftnutzung an der Universität Dortmund", Mundo, vol. 2002, no. 2, 2002.

11.

S. Soter and S. Buchhold, "Low Voltage Converter for Feeding the Net with Fuel Cell Power" in PCIM Asia 2002, 2002.