Electro-thermal loss analysis of the 3L-ANPC converter

The three-level active-neutral-point-clamped (3L-ANPC) voltage source converter (VSC) is used to overcome the uneven loss distribution. In 3L-ANPC VSC the dissipation in the power device is typically characterized by Sinusoidal Pulse Width Modulation (SPWM). The junction temperature and the load current of an actual power converter system are detected to calculate the power loss. This paper, firstly, calculates the total power losses under different power factor angle and modulation depth. Secondly, the thermal resistance and the thermal capacitance of various elements from datasheet are used to express the thermal network. The thermal network is used to estimate each power device junction temperature, and to analyze transient thermal distribution. The results of calculation are compared with that of junction temperature measurements with an infrared camera. Experimental results validate the improvement of the unequal distribution using 3L-ANPC.