Failure Mode Analysis of the 3-Phase 5-Level E-Type Converter

The power electronic converters have a heavily influence in our life-style, since they are today used everywhere in-home applications, office, medicine, industry, and energy transmission machines and processes. The power electronic systems are based on fast-switching power semiconductors, such as diodes, mosfets, igbts, etc. These power devices represent the fragile part in a power electronic converter. Thus, to ensure safety and reliability of the power conversion system, a fault detection method must be provided. When a failure occurs, the fault detection and protection system become the most important function of the converter control unit. If the fault management is not adequate, the entire converter can be totally destroyed, causing catastrophic effects on the entire power conversion system. Accordingly, fault detection, classification, and diagnoses for all power electronic converters, including three phase rectifiers, three phase inverters, DC-DC converters and AC-AC converters, have to be investigated. In this paper, the fault analysis of the 3-phase 5-level E-Type Converter (3Φ5L E-Type Converter) is addressed. The 3Φ5L E-Type Converter is proposed for grid connected applications. All possible converter semiconductor switches and diodes faults are theoretically analyzed. The fault effects, the detectability and the safety shutdown actions are identified and summarized. The analysis is covered by simulation results performed in MATLAB/Simulink. The control algorithm has been implemented in FPGA using LabVIEW environmental. The experimental tests have been performed on the 20kVA prototype multilevel converter in order to validate the proposed analysis.