Direct space vector PWM algorithm for multilevel inverters independent of that of two levels with neutral point balancing

This work proposes a direct space vector PWM algorithm for multilevel inverters without passing by the decomposition of space vector diagram of three-level inverter into two-level, the nearest three vectors (NTV) are determined via identification of the sector that the reference voltage vector belongs and the triangle where the tip point of the reference vector lies. The duty-cycles are determined using a single calculation equation set; the switching sequences that will be used are chosen to generate the output voltages. The redundancies of some output voltage vectors are thoughtfully used to cancel imbalance of dc link capacitor voltages. This algorithm can be generalized into the case of any num ber of levels. Simulation results show the algorithm feasibility.