Multi-level Asymmetrical Inverters Using Two DC Ports with Less Number of Switches and Conversion Stages

Abstract

In recent years, many industrial applications need higher-powered appliances. It is difficult for a single semiconductor switch to connect directly for medium-voltage appliances. In high-power and medium-voltage circumstances, a multi-level power inverter design was provided as an alternative. A multi-level inverter is flexible to use in renewable source, and high-power rating is achieved. Multi-level inverters are categorized into two parts, (1) multi-level symmetrical inverters and (2) multi-level asymmetrical inverters. Here, the asymmetric multi-level inverter is called a dual-DC-port asymmetric multi-level inverter (DP-AMI) that uses only one topology to interface a low/high-voltage DC port and an AC port at the same time. DC source having low voltage like the battery or photovoltaic (PV) modules can provide power directly to the load within a single power conversion stage. It can improve the overall conversion efficiency of the system. The derivation scheme for DP-AMIs topology is given. The principle of operation, schemes used for modulation, and features of DP-AMIs are studied. This inverter’s working principle was evaluated, and the expression of output voltage was obtained. Furthermore, the inverter is integrated with the photovoltaic cell, and its maximum power point is tracked. Finally, the outcome of the DP-AMI is compared to the cascaded H-bridge multi-level inverter. After the simulation, it has been found satisfactory results.