Grid Power Reduced-Component Multilevel Inverter Modelling and Simulation Improvement of Quality

This study detailed the planning, modelling, and testing of a 17-level switched-capacitor multilevel inverter for use in PV energy conversion systems that are connected to the grid. The goal of developing this converter was to reduce the number of power electronic components needed for conventional multilevel inverter topologies while still generating a high-quality AC output. A single DC input source and an optimised switched-capacitor network allowed the converter to produce seventeen different voltage levels from a small circuit. Hardware implementation was simplified without sacrificing efficiency in voltage boosting due to the reduced number of semiconductor switches, capacitors, and gate-driving signals. In addition, the Level-Shifted Pulse Width Modulation (LS-PWM) technique was used to achieve accurate switching control and inherent capacitor voltage balancing without the need for extra balancing circuits. An inrush current limiting inductor was also included to reduce charging current to a minimum and improve the converter's overall reliability. The steady-state operational properties of the proposed converter were verified by analysis in the MATLAB/Simulink environment, which was used for effective implementation.  The simulation results showed that the system was stable, with an output voltage that followed a well-defined 17-level staircase and a waveform for the load current that was almost sinusoidal. With a straightforward circuit design, the converter increased the input voltage from 75 V to about 300 V, a voltage gain of four. A Total Harmonic Distortion (THD) of 2.81% was verified by the FFT analysis, which means that the output waveform is of outstanding quality and meets the power quality criteria of renewable energy applications. Furthermore, the converter demonstrated little power loss during switching, decreased voltage stress on semiconductor devices, and effective balancing of capacitor voltages during operation. Based on these findings, the suggested topology is an attractive option for small and inexpensive grid-connected photovoltaic power conversion systems since it strikes a good balance between high voltage gain, low harmonic distortion, reduced component count, and simplified control.

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