Hybrid Two/Three Level Converter using SiC MOSFETs and Si IGBTs with Topology Reconfiguration for Improved Full Load Range Efficiency

This paper explores the use of a hybrid level-matching converter (HLMC) for improved full range efficiency in high power MW applications. It is shown that a parallel hybrid converter comprised of a parallel connected SiC based three-level Neutral Point Clamped (NPC) topology using 1.7 kV devices and a Si based two-level Half Bridge (HB) topology using 3.3 kV devices can be used to minimize losses across a wide operating range. This is achieved by means of a model predictive control algorithm which selects switching states to exploit the lowest available conduction loss paths and switching loss transitions. Full load range efficiency of the HLMC is compared to those of three phase HB and NPC converters to verify the efficiency improvement of the HLMC in the application of grid side energy conversion.