Five-level high-efficiency rectifier

Abstract

The invention discloses a five-level high-efficiency rectifier suitable for single-phase and three-phase structures. The five-level high-efficiency rectifier comprises a DC power supply and a voltagedividing capacitor module, and each phase of circuit comprises two silicon-based diode modules, an absorption capacitor, a flying capacitor, two silicon carbide based metal-oxide-semiconductor field-effect transistor modules and a filtering inductor. The rectifier is characterized by low switching loss due to the fact that only silicon carbide based metal-oxide-semiconductor field-effect transistors have high-frequency switching, compared with a full silicon carbide based rectifier, silicon-based power diodes are used, and the total cost is lower; and compared with two or three level circuit,five-level rectification can be realized and popularized to intermediate-voltage application. The rectifier is suitable for active front-end occasions of high-voltage large-power application.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a five-level high-efficiency rectifier. Background technique [0002] AC-DC active rectifier technology is a very important part of modern industry. It provides DC power for grid-connected power equipment such as adjustable speed motors, electric vehicle charging piles and communication systems; with the emergence of multi-level topology technology, It is widely used in medium-voltage and high-power occasions, such as: uninterruptible power supply (UPS), medium-voltage transmission system, DC transmission and other fields. Multi-level technology can not only adapt to high voltage and high power, reduce AC side harmonic distortion, device dv / dt switching stress, system common mode voltage and electromagnetic interference, but also reduce the volume of passive components by increasing the number of levels And reduce the switching loss, thereby improving the p...

AI Technical Summary

Problems solved by technology

A hybrid five-level rectifier with four active switches, eight diodes and two Flying capacitors have high efficiency, power density and economy, but in this scheme, the number of capacitors is large, and some diodes will still be turned on and off at high frequency, which has a large reverse recovery loss

[0008] The use of silicon carbide-based devices can greatly reduce the loss of semiconductor devices in power conversion. The five-level rectifier based on silicon carbide diodes and silicon-based metal-oxide-semiconductor field-effect transistors has a large parasitic capacitance due to the large parasitic capacitance of silicon-based metal-oxide-semiconductor field-effect transistors. Switching losses are still high; however, five-level rectifiers using SiC diodes and SiC MOSFETs can significantly reduce switching losses, but at a high cost

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