Applications and Modulation Methods for Modular Converters Enabling Unequal Cell Power Sharing: Carrier Variable-Angle Phase-displacement Modulation Methods

Modular converters based on the connection of multiple power cells have become a competitive solution for many applications, achieving high performance with reduced production and maintenance costs. However, their performance is degraded if the power modules present an unbalanced operation, which is a common case in some applications and/or when they implement active thermal control methods. Variable-angle carrier-based pulsewidth modulation (PWM) strategies face this challenge by minimizing the negative impact of unequal power sharing among the cells. They do this by improving the harmonic quality of the output waveforms, which has a direct impact on the lifetime of the output filters and/or components.