Direct dead-time control - a novel dc-link neutral-point balancing method for the three-level neutral-point-clamped voltage source inverter

Abstract

The neutral-point balancing of 3L-NPC converter has been studied in many works in the past [1], [2], [3], [4]. Nevertheless, the literature shows a theoretical focus neglecting issues like the requirements of the energy flow information for the implementation of the majority of the proposed methods. This paper presents a new dc-link neutral-point balancing method that directly controls the converter dead-times to balance the dc-link. An analytic model is derived to describe the neutral-point voltage dependent on the dead-times. Simulation results are given to verify the model and the new balancing scheme.