Abstract: This paper analyzes a high-voltage frequency converter topology based on multilevel control. By using an output transformer with a center tap, the series and parallel connections of the three-level inverter modules are completed, thereby realizing the high-voltage, high-current multilevel output of the frequency converter. At the same time , by adopting a control method that optimizes the output voltage waveform, specific harmonics of the output voltage are effectively suppressed. Therefore, the frequency converter with this structure is suitable for high-power loads that are sensitive to frequency converter output harmonics. Keywords : frequency converter; topology; multilevel; harmonics In the primary winding of the output converter, there is an additional center-tapped terminal. The two inverter modes can be connected in series or parallel as desired. It can provide high current in parallel mode and high voltage in series mode. In order to eliminate the selected harmonics of the output waveform, an optimized control method is applied, and the result is perfect. Therefore, this type of converter is suitable for heavy loads that are sensitive to the harmonics of the converter. Keywords: inverter; topology; multilevel; harmonics 1 Introduction With the development of power electronics technology, high-voltage high-power frequency converters have been widely used, especially in transportation, metallurgy, and petroleum fields. The requirements for frequency converter capacity are also increasing. High-power frequency converters of several megavolt-amperes or even tens of megavolt-amperes are gradually being applied. Research on high-power frequency converters has also received much attention. Against this background, we undertook the research and development task of multilevel high-voltage high-power converters. It requires an output power of 15MVA, a maximum output current of 2.4kA, a maximum output voltage of 8.6kV, and an output frequency of 300Hz. Based on this objective, and after domestic and international research and analysis, a topology with a center-tapped output transformer was adopted, connecting the three-level inverter modules in series and parallel to achieve multi-level, high-voltage, and high-current power output. Since this inverter will be used to drive loads highly sensitive to specific harmonics, the output waveform and control method were studied. An optimized output voltage waveform control method was adopted to effectively suppress specific harmonics in the output voltage. Simultaneously, the switching device selected was the IGCT, which boasts high reliability, high efficiency, high switching frequency, and extremely high power density. This device is currently the preferred new power switching device for megawatt-level inverters and is receiving increasing attention. [b][align=center]For more details, please click: Research on High-Voltage High-Power Inverter Based on Multi-Level Control[/align][/b]