Microgrid inverter and grid-connected and off-grid control method thereof

Abstract

The present invention discloses a microgrid inverter and a grid-connected and off-grid control method thereof. The method includes: a dispatchable microgrid inverter supporting a microgrid voltage frequency works in different control modes under grid-connected and off-grid conditions; when the microgrid works under grid-connected or off-grid conditions, a central control unit controls the dispatchable microgrid inverter to work in a PQ control mode, a droop control mode or a virtual synchronous generator control mode, and to transmit electricity to a large power grid or absorb electricity from the large power grid according to requirements of the microgrid central control unit; when the microgrid is in an isolated island operation mode, the dispatchable microgrid inverter is required to show voltage source characteristics to the external, and can support the voltage frequency of the power grid; in a microgrid with a master-slave control structure, the dispatchable microgrid inverter works in a VF control mode; and in a microgrid with peer-to-peer control, droop control or virtual synchronous generator control is adopted. The method can control the inverter to work in different control modes according to actual operation conditions of the microgrid, thereby increasing security and reliability of the operation of the microgrid.

Description

technical field [0001] The invention relates to the technical field of a method for feeding power in parallel to a network by two or more generators, converters or transformers, and in particular to a control method for grid-connected and off-grid inverters of a microgrid. Background technique [0002] Microgrid is an effective way to solve large-scale distributed power generation access to the grid, and it is a research hotspot in the field of distributed power generation in recent years. The micro-grid contains a variety of micro-sources, and all the micro-sources in the AC micro-grid are integrated into the micro-grid through the inverter. Therefore, the design and control of the inverter is an important direction of micro-grid research. Distributed power generation is a field that has developed rapidly in the past decade. At present, there are a variety of inverters with mature technologies on the market, including photovoltaic inverters, power generation inverters, and ...

AI Technical Summary

Problems solved by technology

Distributed power generation is a field that has developed rapidly in the past ten years. At present, there are a variety of inverters with mature technologies on the market, including photovoltaic inverters, power generation inverters, and energy storage inverters. These inverters are mostly open protocols , with an external control interface, photovoltaic inverters and wind power inverters can be directly connected to micro-grid applications, but as a key device in micro-grids, energy storage inverters currently have no products that can be applied to micro-grids

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