Research on Overvoltage Caused by Long Cable of Converter

Abstract

Abstract Due to the impact of energy crisis and environmental pollution, wind power generation has developed rapidly as a clean and renewable energy source. The direct drive wind power system has attracted the attention of the country and wind power enterprises due to its simple structure and good reliability. This article conducts in-depth analysis on the overvoltage generated at the input end of the converter in the direct drive wind power generation system, and concludes that there are two reasons for the overvoltage: (1) there is a certain stray inductance in the direct drive wind power generation system. When the IGBT inside the converter is turned off too frequently, the induced electromotive force generated at both ends of the converter overlaps with the DC voltage, resulting in overvoltage pulses; (2) The long cable connection between the converter and the generator causes voltage reflection and generates overvoltage at the converter end. Therefore, if not suppressed in a timely manner, it will cause damage to the converter and generator. In order to prevent overvoltage damage, this article designs a new filtering circuit at the input of the converter to suppress overvoltage. A simulation model is built using Matlab simulation software to verify the advantages and disadvantages of the new filtering circuit. Finally, a comparative analysis of its simulation waveform shows that the new filtering circuit effectively suppresses the overvoltage at the input end of the converter, And the low energy consumption and wide filtering range effectively protect the safe operation of the converter.