A Generalized High Gain Multilevel Inverter for Small Scale Solar Photovoltaic Applications

Abstract

The contribution of renewable energy, especially small-scale solar photovoltaics (PV), is increasing exponentially in the energy sector. In general, high gain DC-DC converters are used as front-end converters to increase the low voltage of PV panels; further, the DC-AC converter (multilevel inverters) is used for standalone AC loads or grid integration. To avoid the front-end converter and achieve both objectives, this paper proposes a nine-level quadruple boost inverter topology for small-scale solar PV applications. The proposed topology operates on a switched capacitor technique to boost the voltage, and has self-voltage balancing of capacitors. This paper presents the detailed operation of the proposed nine-level inverter, voltage stress calculations, loss analysis, and designing of circuit parameters. In addition, a high-gain generalized multilevel inverter (MLI) topology is also reported. Furthermore, the proposed MLI is compared with competitive inverters available in the recent literature. The proposed MLI topology has advantages such as a minimum total standing voltage and a reduced component count; it can also produce bipolar voltage inherently. The performance of the proposed MLI topology is validated through the MATLAB-based simulations and an experimental prototype. Further, the experimental results are presented by considering load variations, modulation index variations, and output frequency variations. The experimental efficiency obtained is in the range of 96.2% to 92.8% for proposed 9-level inverter.

Keywords

• High-gain multilevel inverter
• small-scale solar PV
• switched capacitor
• self-voltage balancing