Novel Three-Phase Four-Wire Inverter with Quasi-Z-Source and LCC Networks

Abstract

The three-phase four-wire inverter is increasingly coveted these days because of its superior performance, i.e. relatively low DC bus voltage and its ability to handle unbalanced load currents. This article presents a new three-phase four-wire inverter with a Quasi-Z source and LCC. The novel topology has the ability to overcome the drawbacks of traditional voltage source inverters (VSI); for example, Balance the AC voltage and Boost the output voltage, use other reduced power switches, the desirable use of DC voltage, and better dynamic performance under closed-loop control than the existing scheme. The difference between new models and traditional ones is for the boost voltage output is greater than the input and the traditional output is lower than the input. However, existing schematics are bulky or complex with transformers, additional power switches, and corresponding control or poor performance when using DC voltage. The AC voltage of each output can be equal and consistent with the desired voltage, even under various unbalanced loads. The analysis of the characteristics and the design principle of the four-wire inverters and LCC network are presented theoretically. Simulation studies verify the performances of the proposed strategy under balanced and unbalanced load conditions. Index Terms—Inverter, LCC network, unbalanced loads Quasi-Z-source inverters (qZSI), Modulation strategy.