A novel static frequency converter based on multilevel cascaded H-bridge used for the startup of synchronous motor in pumped-storage power station

Research highlights: → A novel Static Frequency Converter (SFC) based on multilevel cascaded H-bridge (CHB) topology is proposed and used for the reversible pump-generating units in pumped-storage power station. → The novel SFC based on CHB has compact configuration, low current harmonic distortion and fast speed response. → Rotor position and Grid connection are realized successfully by the novel SFC. -- Abstract: A novel static frequency converter (SFC) is proposed and is used firstly to start the reversible pump-generating units in pumped-storage power station. Multilevel cascaded H-bridge (CHB) topology and Insulated Gate Bipolar Transistor (IGBT) are applied in the novel SFC. In comparison with the conventional SFC adopting load-commutated inverter (LCI) which is composed of silicon-controlled rectifier (SCR), the novel one has plenty of advantages such as compact configuration, low current harmonic distortion and fast speed response, and these advantages have been verified during 2-year operation at Xiang Hong Dian Pumped-storage power station in China. This application shows that the novel SFC greatly enhances the reliability and success rate of connecting to grid for starting up the pump-generating units. The principle, characteristic and performance of the novel SFC are described in this paper, and some key issues related to the startup of the units of the pumped-storage power station are also presented.