A COMPREHENSIVE ANALYSIS OF MULTI-LEVEL INVERTERS IN SINGLE-PHASE PHOTOVOLTAIC SYSTEMS

This paper explores single-phase grid-connected inverters for small-scale applications, typically below 10 kW. It introduces a novel solution: a single-phase seven-level inverter for grid-connected photovoltaic systems. Unlike traditional three-level inverters, this design aims to mitigate issues like increased switching losses and interference. It employs a unique PWM control scheme utilizing three identical reference signals offset to the triangular carrier signal’s amplitude, generating seven output voltage levels from the DC supply. MATLAB analysis demonstrates the inverter’s behavior, showing its ability to achieve the desired voltage levels through modulation index control. A comparison with an 11-level inverter design underscores the effectiveness of the proposed seven-level inverter in improving output waveforms and reducing total harmonic distortion.