A Reduced Switch Count, Self-Balanced, N-Level Inverter Based on a Dual T-Type Configuration

A new Dual T-Type modular N-Level inverter topology is presented in this paper, featuring less power switches, gate drivers, and diodes, than inverters based on traditional multilevel topologies, such as Neutral Point Clamped, Flying Capacitor, T-Type and Cascaded H-Bridge. The proposed topology produces N level output and offers an intrinsic capability of capacitors voltage self-balancing thus eliminating the need of auxiliary sensors or voltage balancing algorithms, leading to a reduction of cost and power losses. A Nearest Level Modulation (NLM) technique is used to enhance flexibility and facilitate digital implementation, mostly in those applications where the converter's level count is high. In particular, such a goal is achieved by the NLM avoiding the use of a triangular carrier wave, because the switching states and the duty cycles for each phase of the converter is immediately calculated. Preliminary simulations have been performed to evaluate the performance of the proposed topology in terms of efficiency and power quality improvements.