Comparative Performance Analysis of Conventional and Reduced-Switch Single-Phase 21-Level Multilevel Inverters for Renewable Energy Applications

Multilevel inverters are widely used in power-electronic applications, particularly in renewable-energy systems, because they can provide improved output-voltage quality with reduced switching losses and lower harmonic distortion. This paper presents a comparison between a conventional single-phase 21-level cascaded H-bridge multilevel inverter and a single-phase 21-level topology that uses fewer switches and DC sources. The switching angles for both configurations, along with the timing required to generate the IGBT gate pulses, are determined using the Equal Phase (EP) method. The conventional cascaded H-bridge configuration requires 40 IGBT switches and 10 independent DC sources to produce a 21-level output. In contrast, the reduced-component topology achieves the same number of output levels using 8 IGBT switches and 4 independent DC sources. The reduced number of power devices simplifies the circuit structure and can lower the overall implementation cost. The performance of both inverter configurations is evaluated through MATLAB/Simulink simulations.