Design of a Single Phase Twenty Five Level Grid Connected Inverter for Photovoltaic System

Galvanic isolation is a crucial component of grid-connected solar PV systems. Despite the increasing adoption of multilevel inverters (MLIs) for grid-connected applications, the literature lacks sufficient discussion on the isolation of these inverters. This paper introduces a 25-level isolated multilevel inverter topology that utilizes only fourteen switches. The proposed configuration incorporates three transformers, each connected via a combination of three bidirectional switches and two H-bridges. This single-phase isolated inverter efficiently generates a 25-level AC output voltage with a voltage gain of 6 while requiring fewer switches. The design of the proposed converter is compared with state-of-the-art multilevel inverters described in the literature. Simulations conducted using MATLAB software demonstrate that the proposed MLI delivers high-quality power, even under dynamic conditions.