A new magnetic linked three-phase multilevel inverter with reduced number of switches and balanced DC sources

This paper presents a generalized structure of a new three-phase multilevel inverter (MLI) which ensures better performance with the minimum number of components for different applications including DC power supply-based renewable energy sources. The proposed MLI topology is developed in the form of several basic blocks which are individually made of a DC voltage source and a semiconductor switch. All the balanced DC sources required for the proposed inverter are made through a high-frequency magnetic link. The single–phase and three-phase five level (5-L) inverters with the rating of 3.5 and 100 kVA, respectively, are simulated, while a five level (5-L) single-phase inverter is implemented for demonstrating the switching strategy and different operational modes. The rigorous calculations are presented to determine switching losses and conduction losses which are minimum because only three conducting switches are responsible for generating each voltage level during every operating mode. The structure of the aforementioned inverter provides optimized value of total standing voltage (TSV = 5.5Vdc with 5-L single-phase leg) of the system. The proposed inverter offers energy conversion efficiency of 94.84% for 5-L single-phase leg which is significantly enhanced and it also minimizes the equipment ratings as well as overall costs of the entire system.