Five-level power converter and its control method and control device

Abstract

The invention provides a five-level power converter, a control method and a control device thereof. Wherein, the five-level power converter includes an inverter and at least one rectifier; the rectifier includes at least one rectification control circuit, four capacitors connected in parallel in pairs, and the first ends of the first capacitors to the fourth capacitors share a common ground; the rectification control circuit is used to input current to the second terminals of the first capacitor to the fourth capacitor respectively, and the polarity of the charges accumulated on the second terminal of the first capacitor and the second terminal of the second capacitor is the same as that of the first capacitor. The polarities of the charges accumulated on the second end of the three capacitors and the second end of the fourth capacitor are opposite; the inverter includes a discharge control circuit, a first inductance unit and a first load connected in series, and the discharge control circuit is used to sequentially Discharge from the second ends of the four capacitors of the rectifier, the discharge current passes through the first inductor unit and the first load connected in series, and the charging and discharging of any one of the first to fourth capacitors are staggered.

Description

Technical field [0001] The present invention relates to power conversion technology, in particular to a five-level power converter and its control method and control device. Background technique [0002] Uninterruptible power system (Uninterruptible Power System, UPS) is a constant voltage and constant frequency power converter that contains energy storage devices and uses rectifiers and inverters as main components. It is mainly used to provide uninterrupted power supply to a single computer, computer network system or other power electronic equipment. When the mains input is normal, the UPS will stabilize the mains and supply it to the load. At this time, the UPS is equivalent to an AC mains voltage stabilizer, and it also charges the internal energy storage device; when the mains is interrupted, The UPS immediately uses the energy stored in the internal energy storage device to continue to provide AC power to the load through inverter conversion, so that the load can maintain...

AI Technical Summary

Problems solved by technology

[0004] Power converters in the prior art can only perform four-level power conversion and output four-level voltage

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