A Carrier-Based Neutral Voltage Modulation Strategy For Seven Level Cascaded Inverters Under Unbalanced Dc Sources

Abstract

This specific project offers a pulse widthmodulation technique to achieve balanced line-to-line output voltages and maximize this modulation index inside the linear modulation range the place that the output voltage could be linearly adjusted inside the multilevel cascaded inverter (MLCI) running under unbalanced dclink conditions. Here we are implementing seven level cascade inverter. In these conditions, this linear modulation variety is lowered, and an important output voltage difference may happen as voltage references increase. So that you can analyze these effects, the voltage vector living space for MLCI can be evaluated in depth. From this analysis, the theory behind this output voltage difference is defined, and the ideal linear modulation variety considering the unbalanced dc-link problem is evaluated. After that will, a neutral voltage modulation tactic is proposed to obtain output voltage balancing and also to lengthen the linear modulation range around the greatest reachable point theoretically. In this proposed method, too large of any dclink difference precludes this balancing of the output voltages. This limitation is also discussed. Both this simulations plus the experiments for just a seven-level phase shifted modulated MLCI pertaining to electric vehicle traction engine drive show that the proposed method will be able to balance line-to-line productivity voltages and also to maximize the linear modulation range beneath unbalanced dc-link disorders.