Three-Level Boost Converter-Based Single-Phase Five-Level T-Type Inverter

Abstract

This study proposes a cascaded power conversion structure composed of a three-level DC-DC boost converter and a single-phase five-level T-type inverter to address the high performance and power quality demands of renewable energy systems. The integrated topology is designed to overcome the limitations of conventional two-level architectures by combining high voltage gain with reduced voltage stress on power switches and minimized total harmonic distortion (THD). The paper presents a comprehensive mathematical model and a robust control strategy, utilizing decoupled loops for total DC-link voltage regulation and neutral-point balancing, alongside a synchronous reference frame current controller for the inverter stage. Simulation studies conducted in the MATLAB/Simulink environment validate the operational characteristics of the proposed system. The results demonstrate that the boost stage maintains a stable symmetric DC-link voltage of 350Vdc (∓175Vdc). Furthermore, the T-type inverter generates a five-level output waveform with a THD as low as 1.22% under steady-state conditions and 1.01% under dynamic loading, compliant with IEEE 519 standards. This confirms the system capability to reduce voltage stress on switches by 50% while ensuring high-quality power delivery.