Self-balanced Quadruple-Boost Nine-Level Switched-Capacitor Inverter for Solar PV System

Switched capacitor-based multi-level topologies have recently gained attention due to their inherent technical superiority suitable for renewable-based applications. In this work, a single-phase boosting nine-level inverter is proposed, which employs a DC-source (V-dc) and three capacitors. It uses 14 switches that require nine independent control signals from the controller, conducts a maximum of 8 switches at any instant and provides a 9-level quadruple-boosted output voltage. The proposed topology is verified for an experimental setup's steady and transient load conditions. A detailed discussion on the balanced charging of the capacitors is also presented. A novel harmonic elimination-based-nearest level modulation scheme is proposed, wherein the simplified control scheme of the nearest level control is extended to eliminate the undesired low-order harmonics from the output voltage waveform of the 9-level inverter. Moreover, its merits of a simplified control, lower power loss, reduced total voltage stress and enhanced voltage gain are discussed in comparison with various 9-level inverters in detail.

Automated summary

This study proposes a single-phase boosting nine-level inverter which utilizes a DC-source and three capacitors, and it is verified for steady and transient load conditions. It also introduces a novel harmonic elimination-based-nearest level modulation scheme to eliminate undesired low-order harmonics from the output voltage waveform. The merits of this topology, including simplified control, lower power loss, reduced total voltage stress, and enhanced voltage gain, are discussed in comparison with other 9-level inverters.