Implementation and performance of a 9-level switched-capacitor (SC) multilevel inverter (MLI) with 4 × voltage gain for grid-tied photovoltaic systems

In this article, the details of the development and result analysis of a 9-level SC-MLI have been presented. The proposed system achieves a quadruple voltage gain (4 ×) and generates a 9-level waveform. The proposed system not only achieves a quadruple voltage gain (4 ×) as an advantage but also used minimal component-efficient architecture; it utilizes only three capacitors, diodes, and 9 power switches, thereby minimizing system cost and complexity while enhancing reliability. A Phase Disposition (PD) Pulse Width Modulation (PWM) is implemented for precise switching control. During the discharging and charging of the capacitor spike occurs. To address this inherent challenge, a small inductor was added, which effectively suppresses current inrush and extends component lifespan. A comprehensive comparative analysis was conducted to evaluate the proposed topology's superiority over existing9-level SC-MLIs in terms of component count, voltage gain, and efficiency. Moreover, the closed loop with PV tied to the grid was analysed, and the proposed system ensures MPPT of the solar photovoltaic. To verify the theoretical analysis, experimental verification through a 1.4 kW laboratory prototype, controlled via a dSpace 1103 platform, and simulations done in MATLAB SIMULINK, was conducted. Finally, the proposed efficiency of the proposed topology was exceeding 97%, and the THD of the grid current was below 2% and, confirming the theoretical analysis.