Comparative Study of PWM Modes for GaN-based Three-Level ANPC Inverter

A three-level active neutral point clamped (3L-ANPC) inverter is designed by the interconnection of three half-bridge power units (HFBs) with 650 V GaN devices. The selected switching mode of operation decides the high and low-frequency switching HFBs. The switching mode also determines the critical commutation path and the decoupling capacitors’ location. Based on this, three cases of 3L-ANPC design and control are identified in this paper. The key performance parameters considered for the comparative study are - inverter efficiency, thermal stress distribution, and peak transient voltage. The parasitic inductances and thermal resistance critical to determining peak transient voltage and junction temperature rise are determined through Q3D simulation and experimental results, respectively. A simulation study based on the parameters is then used to present a comparative performance analysis of the three considered cases.