Performance evaluation of multi-level inverter fed open-end winding IM drive under two different modulation schemes

The conventional level shifted triangular carrier (LSTC) based space vector pulse width modulation (SVPWM) scheme for open-end winding induction motor (OWIM) drive produces a better harmonic spectrum than the phase shifted triangular carrier based SVPWM, but it does not generate an even number of level operation which results in increase in switching losses specially at lower speed range. To reduce the switching losses at lower speed range and to get the even number of level operation LSTC based SVPWM scheme is proposed in this paper. To verify the effectiveness of proposed scheme a hardware prototype of 9-level inverter fed 1.5kW OWIM drive is implemented and performance of the drive is evaluated with proposed and conventional level shifted triangular carrier based SVPWM schemes.