A hybrid cascaded multi-port power electronic transformer and its control method

Abstract

The invention discloses a multi-port power electronic transformer with a hybrid cascade structure. The power electronic transformer includes a rectification stage and an intermediate isolation stage. The rectification stage is formed by cascading M hybrid cascade modules. module and n sub-modules, the input end of the H-bridge rectifier module is connected to the grid after being cascaded, the output end of the H-bridge rectifier module is connected to the input end of the module after the n sub-modules are connected in series, and the output of the M*n sub-modules The terminals are respectively connected to the input terminals of the corresponding isolation modules; the output ports of the M*n isolation modules are all used as the DC output ports of the power electronic transformer, and the DC output ports are connected in series and parallel according to the required voltage level and output capacity. The invention is particularly suitable for the application of high-voltage electric conversion to multi-port low-voltage occasions; it can meet the requirements of the same number of DC terminals, reduce the number of devices, and greatly save costs; the fully modular structure enables good capacity expansion.

Description

Background technique [0001] In recent years, with the development of high-power power electronic device technology and modern control theory, a device that realizes electric energy conversion through power electronic technology—Power Electronic Transformer (PET) is becoming more and more popular among domestic and foreign scholars. Pay attention to. At present, power electronic transformer equipment for distribution network has been put into operation. PET has broad application prospects due to its excellent characteristics of high controllability, high power supply quality and less harmonics. However, the power electronic transformer with the existing structure also has some disadvantages, especially the application under the occasion of multiple power sources. [0002] In the traditional multi-level topology, with the increase of the number of levels and DC ports, the required power electronic devices and the complexity of the topology will greatly increase. However, in t...

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Problems solved by technology

Disadvantages of prior art 1: (1) The number of voltage levels on the high-voltage side is small, and the harmonic content is relatively high

(2) The inverter circuit includes multiple power conversion modules, the components are redundant, and the cost is high

Disadvantages of prior art 1: (1) The number of voltage levels on the high-voltage side is small, and the harmonic content is relatively high

(2) The inverter circuit includes multiple power conversion modules, the components are redundant, and the cost is high

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