Comparative loss evaluation of SiC semiconductors and capacitors in 800-V DC-Link for NPC family structures

Abstract

Power losses play a crucial role in the performance of an electric drive, and inverters are one of its constituent parts. This paper evaluates power losses and the possibility of increasing the power density by decreasing power losses, the size of the DC-link capacitors, and the number or size of the semiconductors. Besides the selection of components and operating switching frequency, the structure of an inverter affects the power density. Different kinds of capacitors and semiconductors are compared and analyzed in this paper in different 3-level inverter topologies. NPC, ANPC, and T-type NPC (TNPC) are compared in a range of switching frequencies from 10 kHz to 50 kHz to find the best topology, capacitor, and semiconductor in every single step of switching frequency. A constant thermal situation is considered to meet needed temperature restrictions and have a fair comparison. Simulations and calculations are performed for 800 V DC-Link voltage, 70 A peak output current NPC, ANPC, and TNPC inverters in MATLAB Simulink and PLECS blockset software linked together.