Application of parallel connected NPC-PWM inverters with multilevelmodulation for AC motor drive

摘要

The neutral point clamped (NPC)-PWM inverters have been put intonpractical use for large capacity AC motor drives, because of their manynadvantages. With the increase in use, still larger capacity invertersnare also expected. In this paper, a parallel connected NPC-PWM inverternis applied for AC motor drive. The conventional modulation techniquesnare extended to improve the inverter characteristics. To determine annoptimum modulation for controlling the parallel connected NPC-PWMninverter, various modulation techniques are devised and discussed, whosenresults are verified by experiment