Common-mode conduction EMI (Electromagnetic Interference) modeling method and device for MMC (Modular Multilevel Converter) three-phase grid-connected inversion system

Abstract

The invention discloses a common-mode conduction EMI (Electromagnetic Interference) modeling method and device for an MMC (Modular Multilevel Converter) three-phase grid-connected inversion system. Onthe basis of the propagation characteristics of common-mode conduction EMI, the high-frequency equivalent model of each key component in the MMC three-phase grid-connected inversion system is combined to establish the common-mode conduction high-frequency EMI model of the MMC three-phase grid-connected inversion system, a common-mode conduction EMI frequency domain prediction result obtained on the basis of a superposition principle is compared with an EMI frequency spectrum of which the time domain simulation waveform is subjected to FFT (Fast Fourier Transform) so as to discover that a frequency domain simulation result and a time domain simulation result can be favorably matched in 10kHz-10MHz, and the validity of the common-mode conduction high-frequency EMI model, which is put forward, of the MMC three-phase grid-connected inversion system can be verified. By use of a frequency domain prediction method, the common-mode frequency domain prediction of an MMC converter is realized,the EMI prediction time of the MMC converter can be greatly shortened, and the design of the EMI filter of the MMC device is effectively guided.

Description

technical field

[0001] The invention belongs to the technical field of EMI prediction of power electronic devices, and more specifically relates to a common-mode conduction EMI modeling method and device for an MMC three-phase grid-connected inverter system. Background technique

[0002] In recent years, the flexible direct current transmission technology using fully-controlled power electronic devices such as insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT) has the advantages of fast dynamic response, good controllability and flexible operation mode. widely used in power transmission systems. Due to the limitation of withstand voltage of power electronic devices, multi-level conversion must be used to be suitable for high-voltage and large-capacity flexible DC transmission systems. A modular multilevel converter (MMC) is used to divide the high voltage into multiple levels and distribute them to each device and module, so that the voltage stress...

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