Control of five level inverters with SPWM

ABSTRACT Master Thesis CONTROL OF FIVE LEVEL INVERTERTERS WITH SPWM Erkan DENİZ Fırat University Graduate School of Natural and Applied Sciences Department of Electrical Education 2005, Page: 106. In this thesis, cascade and diode clamped circuits with IGBT semiconductor switches of three and five-level inverters are simulated in Matlab/SimPower Systems using naturally sampled sinusoidal pulse width modulation technique. There is voltage unbalancing problem in all the circuits of a multilevel diode clamped inverter except for three-level circuit Therefore, this problem has been removed by using voltage balancing circuits in the dc-link of the simulated diode clamped inverter. Moreover, for comparison of the results, the conventional two-level inverter supplying 3- phase RL load is also studied and evaluated in detail. In addition, scalar control (v/f) of a 3-phase induction motor fed by a five level cascade inverter is simulated Key Words : Multilevel inverters, cascade inverter, diode clamped inverter, voltage unbalancing problem, sinusoidal pulse width modulation technique, scalar control (v/f). XIII