Middle-high voltage variable frequency speed control circuit based on modular multilevel converter (MMC)

Abstract

The invention relates to a middle-high voltage variable frequency speed control circuit based on a modular multilevel converter (MMC). The middle-high voltage variable frequency speed control circuit based on the MMC comprises a cascade rectifier circuit and a cascade inverter circuit, an input capacitor is connected with an output capacitor through a high-frequency isolated direct current / direct current (DC / DC) converter, the high-frequency isolated DC / DC converter comprises a primary side H bridge with four power switch devices, an output end of the primary side H bridge is connected with a primary side coil of a high-frequency transformer, a secondary side coil of the high-frequency transformer is connected with an input end of a secondary side H bridge, and an output end of the secondary side H bridge is in bridge joint with two ends of the output capacitor. According to the middle-high voltage variable frequency speed control circuit based on the MMC, a rectification section is isolated from an inversion end of an MMC variable-frequency speed control system by means of the high-frequency isolated DC / DC converter; energy transmission and feedback can be efficiently achieved without an industrial frequency transformer; the high-frequency isolated DC / DC converter is added so that a rectifier and an inverter can safely work without mutual influence, and safe and reliable work can be achieved while efficient energy transmission can be guaranteed.

Description

technical field [0001] The invention relates to an MMC (Modular Multilevel Converter)-based medium and high voltage frequency conversion speed regulation circuit, which is a cascaded MMC frequency converter with high frequency isolation and a medium and high voltage frequency conversion speed regulation circuit based on MMC. Background technique [0002] With the rapid development of science and technology and industrial modernization and the requirement for energy conservation, medium and high voltage power electronic frequency converters used in high-power applications play an increasingly important role. The medium and high voltage frequency converter based on power electronic transformer (PET) has been successfully applied in the fields of high voltage and high power frequency conversion speed regulation, active power filter device and power system reactive power compensation. In recent years, MMC-based medium and high voltage frequency conversion speed control systems h...

AI Technical Summary

Problems solved by technology

Aiming at the problem that the rectifier side and the inverter side of the back-to-back frequency conversion speed regulation system based on MMC cannot be completely effectively isolated, when any accident such as breakdown or short circuit occurs on any side, it will affect the other side, or even the entire rectifier, inverter system, destroying the entire system

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