DTC of Open End Winding Induction Motor fed by two space-vector-modulated inverters

Two different methods, Decoupled and Nearest Sub Hexagon Center (NSHC) algorithms of DTC of Dual Inverter Fed Open End Winding Induction Motor are analyzed in this paper. A SVPWM based 3-level voltages are generated in both methods with two 2-level inverters. In these two methods, inverter-1 pulses are generated normally and inverter-2 pulses are generated with 180° phase shift, this results a 3-level line voltage waveform to the induction motor. In the first method inverter-1 output is superimpose on inverter-2 output with the both inverters are switching at the same frequency in all states. In the second method at a particular state of switching inverter-1 is switched in all states and inverter-2 is clamped to one active state, vice versa in the next state of switching. In order to restrict the zero sequence currents, two isolated dc sources are used. In proposed methods, calculations of regions for space voltage vector, angle calculations sector identification are not required. The imaginary switching times concept greatly reduces the complexity of the SVPWM algorithm. Simulation studies have been carried out and results are presented for the proposed schemes.