Analysis of Common-mode Voltage Characteristics of Variable Speed Pumped Storage Unit Rotor Side Inverter

摘要

Pumped storage power station is the main regulating power source of power system, which has the functions of peak load regulation, frequency regulation, voltage regulation, system standby and soft start. A pumped-storage unit has a large single capacity. To reduce the volume of a single unit and the system cost, the rotor-side frequency converter of the unit usually adopts the medium-voltage three-level scheme. Inverter IGBT switch action will inevitably produce a certain common-mode voltage, affect the long-term stable operation of the unit. This paper studies several modulation strategies of three-level rotor-side converters, compares their advantages and disadvantages, and gives corresponding simulation analysis.