A Simple Space Vector Modulation Method with DC-Link Voltage Balancing and Reduced Common-Mode Voltage Strategy for a Three-Level T-Type Quasi-Z Source Inverter

Abstract

Single-stage converters based on an impedance source (IS) network merged with a multilevel inverter remain a trending research topic, from both the topological and control perspectives, because of their potential in applications involving renewable energy. This paper presents a new, simplified space vector pulse-width modulation (SVPWM) for a three-phase three-level T-type quasi-impedance source inverter (3L-T-type qZSI). The benefits of the proposed modulation strategy include functionalities, such as boosting the input voltage and controlling the neutral-point (NP) voltage using the redundant small vectors, to mitigate the inner capacitors voltages imbalance. The proposed SVPWM guarantees a minimum common-mode voltage while preserving a very simple implementation, thus reducing the complex computations and cascaded proportional-integral (PI) control loops of the conventional SVPWM methods. The proposed algorithm can be applied to different multilevel inverter configurations combined with an IS network. A comprehensive simulation study and experimental results demonstrated the good performance of the proposed control method for dynamic response and imbalance conditions.