An octuple-gain 17-level switched capacitor multilevel inverter with reduced components and low voltage stress for photovoltaic applications

Abstract There is increased interest in developing multilevel inverters with reduced cost and still achieving high power quality. In renewable energy systems, particularly low-voltage photovoltaic systems, voltage gain is also a crucial factor. Ensuring high voltage boost and high-power quality with reduced component count in multilevel inverters is critical for photovoltaic systems, particularly as these systems play an increasingly significant role in the global energy transition. This article proposes a single-source 17-level switched capacitor multilevel inverter consisting of two series-connected, series-parallel units and a capacitor voltage doubling unit. The switched capacitor circuit consists of 12 switches, 4 diodes, and 3 capacitors. The design limits the maximum voltage stress on the switches to half of the output voltage, enabling the use of low-cost, low voltage switching devices. The high boost factor of 8 makes it particularly useful in low-voltage photovoltaic systems and battery applications. This article demonstrates the functional operation of the proposed switched capacitor multilevel inverter, and the nearest level control modulations scheme. A comparative analysis against other 17-level switched-capacitor inverters is conducted to highlight the advantage of reduced cost, while offering high voltage gain, demonstrating advantageous attributes in comparison to other inverters in the same category. The simulation and experimental results are presented to demonstrate the feasibility of the proposed circuit, with its performance evaluated under steady-state conditions, with resistive and light inductive load. It achieves the desired voltage gain of 8, generating the output voltage waveform with a low Total Harmonic Distortion of 4.7%.