The analysis of conduction and switching losses in multi-level inverter system

The multi-level inverter system is very promising in AC drives, when both reduced harmonic content and high power are required. But, as the output voltage level increase, the number of using the semiconductor device is increased. In case of multi-level inverter system, the loss of semiconductor devices cannot be analyzed by conventional methods. The reason is that the loss of each the semiconductor device is different from one another unlike 2-level and the diode clamped inverter system needs extra clamping diode. In this paper, a simple and accurate method of computing conduction and switching loss is proposed for multi-level inverter system. The validity of the proposed method is proven for 3-level and 4-level diode clamped inverter system.