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Microgrid structure and control method based on back-to-back AC-DC converter

A technology of AC-DC conversion and DC converter, which is applied in the direction of AC network circuit, AC network load balancing, power network operating system integration, etc. It can solve the problems of complex micro-grid control strategies and achieve the effect of ensuring the reliability of power supply

Active Publication Date: 2016-11-16
STATE GRID CORP OF CHINA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The microgrid structure in which the inverter is directly connected to the grid is adopted. The main power supply of the microgrid needs to be switched between on-grid and off-grid operation modes, and the control strategy of the microgrid is correspondingly more complicated.

Method used

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  • Microgrid structure and control method based on back-to-back AC-DC converter
  • Microgrid structure and control method based on back-to-back AC-DC converter
  • Microgrid structure and control method based on back-to-back AC-DC converter

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Embodiment 1

[0040] Such as figure 1 , figure 2 as well as image 3 As shown, this embodiment provides a micro-grid structure based on back-to-back AC-DC converters, including a micro-grid management terminal, a distribution network management system, and a distribution network primary system connected to it, and also includes a photovoltaic array, a wind turbine , an energy storage system and a backup power supply, the photovoltaic array, the wind turbine, the energy storage system and the backup power supply are transformed by the first DC converter, the first rectifier converter, the second DC converter and the second rectifier respectively The inverter is connected to the DC busbar of the microgrid, and the DC busbar of the microgrid is connected to a back-to-back AC-DC converter; the inverter link of the back-to-back AC-DC converter is connected to the AC busbar of the microgrid, and the AC busbar of the microgrid is The bus bar is also connected to the microgrid load; the bidirect...

Embodiment 2

[0044] This embodiment provides a control method for a microgrid structure based on back-to-back AC-DC converters as described above, which mainly includes the following three situations:

[0045] (a) When switching from unplanned grid-connected to off-grid, the specific steps are as follows:

[0046] Step S11: The grid-connected point protection terminal detects the voltage amplitude, frequency and current of the first grid-connected point bus bar and the second grid-connected point bus bar, and judges whether there is any abnormality. If abnormal, the grid-connected point protection terminal sends out The command controls the grid-connected switch to be disconnected, and at the same time controls the back-to-back AC-DC converter to switch to an off-grid operation mode;

[0047] Step S12: The back-to-back AC-DC converter switches to the off-grid operation mode, the back-to-back AC-DC converter notifies the source-load balance control terminal to enter the off-grid operation m...

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Abstract

The invention relates to a micro-grid structure and control method based on back-to-back AC-DC converters. The grid-connected protection terminal is used to realize the abnormal protection of the grid-connected point, the switch of the grid-connected point is controlled, and an instruction for switching between grid-connected and off-grid is provided. The source-load balance control terminal is used to realize the micro grid. When the power grid is running on-grid and off-grid, the output of the distributed power generation unit, the power of the energy storage system, the output of the backup power supply, and the overall balance of the active power of the load, the present invention also uses a back-to-back AC-DC converter. It can realize uninterrupted power supply and smooth off-grid switching. In the case of loss of power supply from the distribution network, the micro-grid can smoothly transition to off-grid operation, effectively ensuring the reliability of power supply for the load in the micro-grid.

Description

technical field [0001] The invention relates to the field of distributed power generation, in particular to a microgrid structure and control method based on back-to-back AC-DC converters. Background technique [0002] A typical microgrid is composed of a variety of distributed power generation units, energy storage systems and loads. Microgrid is a new type of power supply and distribution technology. It is an autonomous system that can realize self-control, protection and management. Network operation, can also run in isolation. In 2001, scholars such as R.H.Lasseter in the United States proposed the concept of micro-grid. At present, micro-grid technology is developing towards the practical stage. Microgrid can comprehensively manage distributed power generation units with fluctuating and intermittent output, such as wind power, solar photovoltaic power generation and other types of distributed power generation, and provide a friendly access method to suppress the impac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38H02J3/28H02J9/06
CPCH02J3/28H02J3/382H02J3/388H02J9/06Y02B10/70Y02B70/30Y02E70/30Y04S20/20
Inventor 范元亮陈彬
Owner STATE GRID CORP OF CHINA