A Transformerless Three-phase DC-AC Converter for DC Microgrid

A DC-AC, DC micro-grid technology, applied in the output power conversion device, the conversion of AC power input to DC power output, electrical components and other directions, can solve difficult inverter / rectifier working conditions, output waveform large harmonics , large volume and other problems, to achieve the effect of simplifying the structure, reducing the output harmonic content, and eliminating the third harmonic

Inactive Publication Date: 2018-05-04
SHANGHAI JIAOTONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The added power frequency transformer will bring the problems of bulky size and low efficiency, without adding this transformer, it will be difficult to realize the inverter / rectifier working in a better working state
Because of the large difference in voltage levels at both ends, its modulation rate may be very low, resulting in large harmonics in the output waveform and low efficiency

Method used

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  • A Transformerless Three-phase DC-AC Converter for DC Microgrid
  • A Transformerless Three-phase DC-AC Converter for DC Microgrid
  • A Transformerless Three-phase DC-AC Converter for DC Microgrid

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Embodiment Construction

[0021] The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0022] combine figure 2 , this embodiment describes in detail the transformerless three-phase DC-AC converter for DC micro-grid of the present invention, which includes at least two DC-AC conversion units, here two are taken as an example, two DC-AC conversion units Wrong phase parallel connection.

[0023] In this embodiment, the two DC-AC conversion units are out of phase by 60°, and the required low voltage 400VAC can be measured at the output.

[0024] Such as figure 2 As shown, the conve...

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Abstract

The invention discloses a transformerless three-phase DC-AC converter for a DC microgrid, which comprises: at least two DC-AC conversion units, at least two DC-AC conversion units connected in parallel; wherein: two DC ‑AC conversion units are wrongly connected in parallel. In addition, the CPU can also be used to automatically control the DC-AC converter through PWM control technology. The transformerless three-phase DC-AC converter for the DC micro-grid of the present invention does not need to insert a transformer between the DC bus and the low-voltage power grid, and can allow the DC-AC converter to work in the best modulation rate range, improving the efficiency of the DC-AC converter. converter efficiency and reduced harmonic output.

Description

technical field [0001] The invention relates to the technical field of power electronic conversion, in particular to a three-phase DC-AC converter without a transformer for a DC microgrid. Background technique [0002] Microgrid refers to a small power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, related loads and monitoring and protection devices. It is an autonomous system that can realize self-control, protection and management. It can run in parallel with the external power grid or in isolation. The transmission in DC mode is called DC microgrid. [0003] For the requirement of converting 2000V DC bus voltage to 380V AC grid, the transformation ratio is very high. The general traditional solution is to add a bulky AC transformer, which reduces the requirement for the transformation ratio of the converter. figure 1 Shown is an existing DC micro-grid with a DC bus voltage higher than 2000V. S...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/00
Inventor 王勇李骄阳田杰李建春
Owner SHANGHAI JIAOTONG UNIV
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