Research Of Losses And Open-Switch Fault In T-type Three-level Inverter

Since 1950,power electronics technology has been rapid development,its products have been applied to all aspects of life.The world's scholars,research institutions and companies pay great attention on Multi-level inverter since it has been raised.The converter topology can be divided into two-level topology,three-level topology and multi-level topology according to the number of output levels.The object of this paper is a three-level inverter,T-type three-level inverter,the main research as follows:1.The working principle of T-type three-level inverter is analyzed in detail,and the basic principle of some commonly used modulation strategies is introduced.2.The loss model of T-type three-level inverter is deduced,and the loss of T-type three-level inverter under different modulation strategies is simulated and compared.For example,based on SPWM and SHEPWM two modulation strategies,for different modulation M,different power factor angle ?,different output current conditions Im,analysis and comparison the loss under the two modulation strategies.The loss of IGBT module under different operating modes and its influence on the reliability of T-type three-level inverter are gotten through research.3.The method of open-switch fault diagnosis,the loss of power device under open-switch fault,the power device heat and reliability under open-switch fault.4.This paper builds a T-type three-level inverter experimental platform.The junction temperature of power device under SPWM and SHEPWM strategy was measured by infrared thermal imager,and the junction temperature of the power device under open-switch fault state was measured.The simulation results and experimental results are the foundation of T-type three-level inverter loss and the research of reliability.