Abstract
Recently, the DC-to-AC converters are widely used in many applications. With popularization of the direct DC-to-AC converter, its reliability becomes even more important as well. Reducing the influence on the system of the fault state can effectively improve the reliability of DC-to-AC converter system. In addition, it is good for the protection schemes for DC-to-AC converter by understanding the fault type and fault state of the converter system. The protection schemes for DC-to-AC converter proposed by this research paper are to analyze the fault modes that converters may meet. For instance: Input supply single line to ground fault, Rectifier diode short-circuit fault, Earth fault on dc bus, DC bus capacitor short-circuit fault, Transistor short-circuit fault, Line to line short-circuit at inverter load and Single line to ground fault at inverter load. Direct against the fault type and fault current circuit, put forward the suitable protection schemes, the injury to the converters that lighten the fault. The protection schemes are as the following: NFB (No Fuse Breaker), magnetic contactor, fuse, varistor, DC bus over/ under voltage protection, DC bus over current protection and AC over current protection. The proposed protection schemes in the thesis will be presented and analyzed by computer simulation and laboratory experiment. The research paper, which elaborates the theory and integral functions of protection schemes of inverter, is divided into six chapters, including preface, bibliography, operation principles, results and analysis of simulation and experiments and the conclusion