Analysis and testing on the switching states transitions of hybrid clamped multilevel inverters

Transient abnormal switching states appear between two kinds of stable normal switching states during the operation of the hybrid clamped multilevel inverter. Detailed analysis on the switching states transitions, including the cause of transient abnormal switching states, the switching characteristics of the key devices, is presented in this paper. A quasi online scheme of testing the switching characteristics of the power devices for the hybrid clamped multilevel inverter during the switching states transitions is also proposed. Testing results show the correctness and validity of the analysis. The analysis and testing on the switching states transitions contribute to calculate the voltage and current stresses, the stray parameters and power devices losses, thereby selecting suitable devices and optimizing the structure design and the thermal design of the multilevel inverters.