A Nine-Level Common-Ground Type Multi-Level Inverter for Standalone and Grid-Connected Applications

Abstract

This work proposes a new common ground (CG) 9-level (9L) inverter with only nine switches and three capacitors. The proposed converter can be deployed for high-frequency AC applications with advantages like improved harmonic spectrum and reduced capacitor charging current. The proposed multi-level inverter has three capacitors and has a boosting of 4. The proposed converter provides a CG between the load and source, making the converter leakage current almost zero. The inherent advantage of zero leakage current makes the proposed converter suitable for renewable energy applications. The other advantage of the proposed converter is that most of the switches have low voltage stress, which decreases the cost of the converter. The cost analysis, design of components, modulation strategy, and comparison of the proposed topology with other counterparts are done in detail. The loss analysis and efficiency of the converter in laboratory conditions are also presented. The converter performance in a steady state and with changes in loading conditions is validated by building a prototype, and experimental results are shown. The grid-connected results are being shown in real-time with the help of the Typhoon Hardware in the Loop setup.