Implementation of Cascade Multilevel Inverter in Distribution Systems as Power Line Conditioner

This paper deals with the implementation of cascade multilevel inverter-based STATCOM, which employs H-bridge inverter. The STATCOM system is modeled using the d-q transform, which calculates the instantaneous reactive power. In this paper, a power line conditioner using a cascade multilevel inverter is presented for voltage regulation, harmonic filtering and reactive power compensation (var). 11 level STATCOM is selected as demonstration. The cascade multilevel converter consists of five single-phase full bridges in which each bridge has its own DC source. This new inverter can: 1) It can eliminate transformers of multilevel inverters used in conventional static var compensators; 2) make possible to direct connect to power distribution system in parallel and series without any transformer; 3) generate almost sinusoidal voltage. This paper focuses on feasibility and control schemes of the cascade inverter foe voltage regulation and harmonic filtering in distribution systems. The results are analyzed and discussed.