Resonance-type power electronic current transformer and current transformer device

Abstract

The invention relates to the technical field of power electronic current transformers, and provides a resonance-type power electronic current transformer and a current transformer device. The current transformer comprises an input-stage rectifying circuit and a rear-stage DC / DC circuit. The input-stage rectifying circuit comprises three bridge arms. Each bridge arm is composed of an upper half bridge arm body and a lower half bridge arm body. The midpoints of the bridge arms are connected with three phases of a high-voltage alternating-current power grid respectively. Each half bridge arm body comprises n module units. Ports of the module units are connected in a head-to-tail mode to form a bridge arm structure. Due to the high-frequency isolation of the input side and the output side, a heavy lower-frequency transformer is removed, and meanwhile efficient energy transmission and intelligent control are achieved. Harmonic wave transmission between different power grids and mutual influences caused by failures of the different power grids can be intercepted, meanwhile, the range of the output voltage is wide, continuous adjustment of the current and the voltage can be achieved, system operation information of the current transformer is easy and convenient to collect, mutual communication can be achieved among a plurality of current transformer systems, and the intelligent power grid is obtained.

Description

technical field [0001] The invention relates to the technical field of power electronic converters, in particular to a power electronic converter system capable of realizing high efficiency, high-frequency isolation, high-voltage input, wide-range stable voltage output, and bidirectional energy flow. Background technique [0002] With the increasingly serious ecological environment problems and the depletion of traditional energy sources, energy-saving technologies and efficient use of new energy sources are receiving attention and support from all over the world. Undoubtedly, as an important application aspect of energy-saving technology, smart grid has become a research hotspot in industry and academia. Distributed power generation is an important way to utilize new energy. The combination of distributed power generation and smart grid has become an inevitable trend of the future grid. [0003] The traditional new energy distributed power generation system realizes the e...

AI Technical Summary

Problems solved by technology

However, limited by the current development level of power electronic devices, this architecture also requires a power frequency distribution transformer to match the output of the bidirectional power electronic converter and the AC bus voltage

[0004] Although the production process of industrial frequency transformers is simple and the price is low, industrial frequency transformers are large in size, heavy in weight, and do not have the ability to isolate faults. At the same time, the power frequency transformer cannot maintain the stability of the secondary side voltage, and cannot realize the automatic adjustment and intelligent management of energy, which has become increasingly unable to meet the new needs raised in the development of the power system, such as the smart grid

[0005] In order to flexibly control the energy flow in the power grid, effectively utilize new energy sources, and reduce the size of transformers, scholars have proposed some solutions, such as the EU's UNIFLEX-PM project and North American solid-state transformer structure (SST, also known as power electronic transformers). ), these schemes can control the two-way flow of energy, and at the same time use high-frequency transformers to achieve electrical isolation, but in these schemes, the circuit structure is complex, the control is cumbersome, the loss is large, the efficiency is low, and the redundancy design is complicated. Once a certain device fails , the system needs to be powered off for maintenance, and the reliability is low, so these solutions cannot meet the requirements of the power grid

[0006] The short-distance transmission voltage in the domestic power system is usually 10kV and 35kV, while the current active switching devices (IGBT, SiC MOSFET, etc.) suitable for high-power applications have a withstand voltage below 6kV, and commonly used IGBTs with 1700V and 3300V withstand voltage , so the common converter structure cannot meet the high voltage requirements

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