Power electronic transformer with energy storage device

Abstract

The invention relates to a power electronic transformer with an energy storage device. The power electronic transformer is characterized in that the high-voltage side of the power electronic transformer is connected with a 10kV power distribution network, the low-voltage side of the power electronic transformer is connected with a 400V-grade power distribution network, three-phase 10kV alternating-current voltage is subjected to voltage division and isolation conversion through an A-phase circuit, a B-phase circuit and a C-phase circuit, high-voltage alternating current is converted into direct current, and the direct current is connected with direct-current buses P and N; and the direct current buses P and N are electrically connected with the energy storage type Quasi-Z source inverter to convert direct current into three-phase 400V grade alternating current to be connected with a low-voltage power distribution network. According to the power electronic transformer, the number of high-frequency transformers and submodules is reduced, the power density of the power electronic transformer is improved, harmonic waves brought by the power electronic transformer to a superior power distribution network can be effectively restrained, the stability of a low-voltage power distribution network is maintained under the condition that the quality of electric energy is guaranteed. The transformer can also participate in voltage / frequency adjustment of a superior power distribution network, and has certain inertia and damping.

Description

technical field [0001] The invention relates to the technical field of electrical engineering, in particular to a power electronic transformer with an energy storage device. Background technique [0002] Power electronic transformer is a transformer that combines power electronic devices with high-frequency transformers and realizes electric energy conversion through power electronic conversion technology. In addition to basic functions such as voltage conversion, electrical isolation, and energy transfer, it also has high controllability. , can realize the advantages of waveform, power flow, power quality control and automatic protection control, etc., and is an ideal power distribution equipment for distribution network. It is widely used in on-board converter systems for electric locomotive traction, smart grid / energy Internet and distributed renewable energy generation grid-connected systems. [0003] Conventional power electronic transformers use conventional inverters...

AI Technical Summary

Problems solved by technology

[0003] Conventional power electronic transformers use conventional inverters at the output end. In order to prevent damage to the inverter due to simultaneous conduction of the upper and lower switching tubes of the same inverter bridge arm, a dead time is often added to the switching signal of the bridge arm switching tube, which instead makes the output The AC voltage waveform is distorted

In addition, the topology does not have a modular structure, and as the number of levels increases, the circuit topology becomes extremely complex, so a power electronic transformer with energy storage device is needed

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