A Five Level Switched Capacitor Multi-Level Inverter with Soft Charging and Reduced Switching Loss

Abstract

Switched-Capacitor Multi-Level Inverters (SCMLI) have become popular now a days due to their unique advantage of voltage gain capability. In SCMLI, the capacitors are linked in parallel to the input DC source to charge in a short period. However, the capacitor draws impulse charging current from the DC source. This impulse charging current damage the devices. In this paper, a novel 5-Level SCMLI with a voltage gain of 2 is proposed with the soft charging capability. It requires 6 switches, 2 diodes, 2 capacitors, 2 inductors, and a single DC source. The two capacitors are self-balanced without any requirement of voltage sensors. Four out of six switches are switched at fundamental frequency to ensure low switching losses. Further, it requires only three conducting switches to carry the load current for each level of voltage. The suggested topology maintains the minimum number of switches and Total Standing Voltage (TSV) in comparison to the existing five-level self-balanced SCMLI topologies with a voltage boost of 2. To explain the superiority of the suggested topology, a detailed comparison with the current topologies is provided. The proposed 5-Level SCMLI is simulated using the fundamental switching frequency modulation technique with help of the MATLAB/SIMULINK tool and it is verified experimentally with the help prototype model developed in the laboratory using dSPACE 1104.