Julius Luukko

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The current characteristics of two types of parallel three-phase voltage source inverter configurations are analyzed, and the suitability of different pulse width modulation methods in the control of parallel inverters is discussed. The analysis and discussion are based on state-space models derived in this paper and presented for the parallel connection of(More)
Traditionally, large DC-link capacitors have been used in voltage source inverters. By using MPPF-type capacitor the line current harmonic content is improved and the unreliable electrolytic capacitor can be omitted. In this paper, the dynamic behavior of an inverter with small DC-link capacitor has been studied by simulations and laboratory tests. A new(More)
Modern frequency converters use ASIC circuits to handle fastest operations and microprocessors for slower operations. By using FPGA circuit it is possible to implement a powerful microcontroller inside the FPGA circuit and replace the combination of ASIC and microprocessor with a single chip solution. The FPGA implementation allows more flexible(More)
Switching pattern in multilevel inverters has to be restricted to single voltage level steps to limit the overvoltages caused by the cable reflections and du/dt. This restriction affects not only the single-phase voltage pattern but the maximum allowed change of a voltage reference vector in three-phase operation and as a result also the maximum achievable(More)
Development of PLDs (programmable logic device) like large FPGA (field programmable gate array) circuits allow those to be used as modern control platforms for power electronics. Using FPGAs and efficient control algorithms better response times can be gained compared to processor implementations. When using a large FPGA circuit an efficient structure has(More)
Simulation of static and transient behaviour of wind power plants is important both for grid companies and the power plant suppliers. Simulating a full-power converter based wind power drive includes the simulation of a large electrical circuit. Building such a model with a circuit simulation program requires details which are not necessary from the(More)
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