Junction temperature acquiring system of the 3L-ANPC inverter based on labview

The three-level active-neutral-point-clamped (3L-ANPC) inverter is used to solve the problem of uneven loss distribution in the three-level neutral-point-clamped (3L-NPC) inverter. Labview is widely used for industrial monitoring. As a common industrial bus, RS485 is used to connect and control several devices. MLX906I4 is an infrared thermometer for non-contact temperature measurement. In this paper, firstly, the topology and total loss of the 3L-ANPC inverter is analyzed. Secondly, a temperature acquiring system consists of a lower system and PC computer has been built. The lower system is composed of four MLX906I4 chips and one AT89S52 MCU, while the software in PC is developed by Labview. The communication between PC and the lower system is realized by RS485 bus. Experimental results are compared with those of junction temperature measurements with an infrared camera. The comparison of results validates the accuracy and validity of this temperature acquiring system.