This paper presents a concept of an NxM Matrix Converter (MC) modeling under periodic control strategy patented in Poland. This strategy allows to change an Nphase input system of voltages and current with the frequency fi to the M-phase output system with the frequency fo, maintaining both systems symmetrical and providing small distortions of voltage and current waveforms at rather high frequencies. In this paper the control strategy is extended for dynamic states when one of the frequencies is changed. Matrix converter equations have been derived using the constrain matrix, which is determined by the switch states. The equations have the hybrid form of a multi-port circuit. To simplify these equations the symmetrical components of input and output voltages and currents have been applied. As a result, rather simple equations have been found. They can be interpreted to an equivalent scheme. All considerations are illustrated using an exemplary 6H3 matrix converter.
The Small Hydro Power Plants allow to increase the energy amount from renewable sources, especially from small rivers in mountainous areas. This paper presents a new concept of a energy conversion system for application in a Small Hydropower Plant (SHP) which is based on a permanent magnet generator (PM generator) with a propeller turbine integrated with the generator rotor. The PM generator can work at a variable speed and therefore energy produced by the PM generator has to be converted by means of a power electronic unit to fit to the three-phase power grid parameters. For this concept, dimensions and parameters of the PM generator were specially designed on account of integration with water turbine. The paper precisely describes elements of energy conversion system and also presents the results of numerical tests for chosen working conditions. An original algorithm of control strategy for power electronic unit was used to adjust generated energy to the required parameters of the three-phase grid.