Small vector PWM strategies of three-level inverters

The PWM strategies that insure the lowest current and torque pulsations of three-level inverters are investigated for the voltage control region I in which only the small voltage vectors are used It is shown that these PWMs can he realized by two different methods. For both methods the carrier-based realizations are presented. The theoretical derivations of voltage spectra of these methods are derived and shown. The results were checked by a computer simulation; within this scope the voltage distribution between the two inverter input condensers was investigated too.