Implementation of a novel nine-level double boosting multi-level inverter

Abstract

Switched capacitor multi-level inverter topologies have garnered the attention of industrial power electronics researchers due to their potential in different industrial and renewable energy source applications. This paper proposes a novel nine-level, twofold voltage gain boost (9L2x) inverter designed for photovoltaic (PV) applications, addressing common challenges in transformer-less multi-level grid-tied PV inverters, such as leakage current and output voltage bucking. This design utilizes switched capacitors (SC) with a common ground, achieving a twofold voltage boost without needing an extra boost converter. The proposed topology reduces the active switch count, enhances power density, and lowers costs while ensuring self-balancing SCs and minimizing total standing voltage. The common grounding mitigates leakage current, making the system more efficient. The proposed topology features a diode-inductor circuit at the input DC side to reduce inrush current, decrease capacitor voltage ripples, reduce the total harmonic distortion of the MLI output voltage, and improve efficiency. A proportional-integral controller manages active grid power, and a modulation strategy ensures SC voltage balance. The paper delves into intricate details concerning the inverter’s circuitry, control methodologies, and pulse-width modulation scheme. This nine-level inverter design is thoroughly validated through extensive simulations and practical hardware-in-the-loop experiments. The results consistently affirm the effectiveness and feasibility of this novel inverter, positioning it as a significant advancement over existing nine-level inverters. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.