Eksperimentalna provjera vektorski upravljanog asinkronog motora visokih performanci napajanog iz matričnog pretvarača

The results of the intensive experimental study of the matrix converter-fed Induction Motors (IM) with high dynamic performance speed-flux tracking field-oriented control algorithm are presented. It is experimentally proven that high performance speed tracking is achieved under heavy dynamic conditions of operation. High quality input/output current waveforms of the matrix converter obtained during steady state conditions of operations for both directions of the power flow. The results of the experimental tests prove that matrix converter does not have limitations for implementation in high dynamic performance vector controlled induction motor drives.U članku se izlažu rezultati temeljite eksperimentalne studije o asinkronom motoru napajanom iz matričnog pretvarača i upravljanom prema načelu vektorske regulacije s visokim dinamičkim performancama slijeđenja referencije brzine vrtnje i magnetskog toka. Eksperimentom je pokazano da se visoke performance slijeđenja brzine vrtnje postižu u uvjetima teškog dinamičkog opterećenja motora. Dobivena je visoka kvaliteta valnih oblika ulazne i izlazne struje matričnog pretvarača za stacionarno stanje i za oba smjera toka energije. Rezultati eksperimentalnog ispitivanja potvrđuju da ne postoje ograničenja na primjenu matričnog pretvarača u vektorski upravljanim asinkronim pogonima visokih dinamičkih svojstava

Combined investigation of collective amplitude and phase modes in a quasi-one-dimensional charge-density-wave system over a wide spectral range

We investigate experimentally both the amplitude and phase channels of the collective modes in the quasi-1D charge-density-wave (CDW) system, K0.3MoO3, by combining (i) optical impulsive-Raman pump-probe and (ii) terahertz time-domain spectroscopy (THz-TDS), with high resolution and a detailed analysis of the full complex-valued spectra in both cases. This allows an unequivocal assignment of the observed bands to CDW modes across the THz range up to 9 THz. We revise and extend a time-dependent Ginzburg-Landau model to account for the observed temperature dependence of the modes, where the combination of both amplitude and phase modes allows one to robustly determine the bare-phonon and electron-phonon coupling parameters. While the coupling is indeed strongest for the lowest-energy phonon, dropping sharply for the immediately subsequent phonons, it grows back significantly for the higher-energy phonons, demonstrating their important role in driving the CDW formation. We also include a reassessment of our previous analysis of the lowest-lying phase modes, whereby assuming weaker electronic damping for the phase channel results in a qualitative picture more consistent with quantum-mechanical treatments of the collective modes, with a strongly coupled amplitudon and phason as the lowest modes