Controller and control method of frequency converter, and control device of variable speed pumped storage generation system

摘要

Problem to be solved: to provide a control device and a control method of a frequency converter for maintaining a voltage balance with a high efficiency and a small capacity energy storage element, and a control device for a variable speed pumped storage power generation system even in the case of a low output AC frequency.A control unit 109 of a frequency converter 103 for interconnecting a rotating machine including a synchronous machine to a power system comprises a plurality of unit converters connected in parallel with a capacitor connected in series, and one end of a series connection is connected to each phase of alternating current The other end of the series connection is provided with arms 105up to wn connected to a direct current terminal.Control deviceAt least an AC voltage removing section for detecting a voltage of a capacitor in a plurality of unit converters constituting an arm and extracting a DC component from the capacitor voltage andArm voltage command generation unit for generating arm voltage command valueCarrier signal generation unit for generating carrier signalA gate pulse generator including a modulated wave generator for correcting an arm voltage command value provided by an arm voltage command generator and.Diagram