Control structure and Converter losses of a 3L-ANPC with GaN HEMTs switching at 100 kHz

This paper presents a model for estimating the converter losses of a drive system consisting of a Gallium Nitride (GaN) 3-Level Active Neutral Point Clamped Converter (ANPC) and a 4.55 kW synchronous reluctance machine (SynRM). First an experimental setup of the ANPC using GaN HEMTs and the control system, which is implemented on a Zedboard (FPGA), is presented. As a second step the turn-on and -off losses of a single GaN HEMT are measured for different current, voltage and temperature values, using a double pulse test fixture. These evaluated losses are used to create a loss model of a single switch and finally a model of the 3L-ANPC. Subsequently the impact of different switching frequencies and modulation strategies on the efficiency of the inverter is investigated. Finally the results of simulations will be compared with experimental measurements of a speed controlled SynRM drive.