A New Family of High-Frequency DC Link Two- and Multilevel NPC Inverters With Compact Design, Fast Dynamic, Enhanced Voltage Balancing, and Voltage Ripple Mitigation

Traditional multilevel inverters (MLIs), such as neutral-point clamped (NPC) and active neutral-point clamped (ANPC) configurations, often rely on bulky capacitors, increasing system size and weight, which limits their application in space-constrained environments such as electric vehicles. This article introduces a novel two-level switched capacitor voltage doubler neutral-point-clamped (SC-VD NPC) inverter as a solution to these challenges. By utilizing high-frequency dc-links, the SC-VD NPC inverter significantly reduces the size of dc-link capacitors while providing a fast transient response. Its voltage balancing is enhanced through a sequential charging method and unique topology, offering advantages over conventional NPC and ANPC inverters, resulting in lower voltage ripple. A detailed mathematical analysis is presented to demonstrate these features. Furthermore, this configuration can be extended to the SC-VD NPC MLI, with three- and five-level topologies introduced, accompanied by a comprehensive comparison of cost, performance, and efficiency. Moreover, a novel one-dimensional space vector modulation (OD-SVM) scheme is introduced providing a simple and efficient method for controlling SC-VD NPC-MLIs. By utilizing voltage vectors to generate the desired reference voltage and selecting the closest vectors for dwell time determination, the OD-SVM streamlines the modulation process. Simulation and experimental results for two and five-level proposed MLIs validate these advantages.