Microgrid Negative Sequence Voltage Compensation Method and Device for Inverter Interface Microsource

Abstract

The invention discloses a micro-grid negative sequence voltage compensation method for an inverter interface type micro-source, which is applied to an inverter with a three-phase three-bridge arm structure externally connected to an LC filter. Since the micro-source is connected through the inverter The DC bus of the microgrid obtains the filtered current i of the inverter l , output voltage u o , output current i o And after the average value of the output current negative sequence components of all inverters in the microgrid, the negative sequence compensation voltage value of the inverter is calculated by the negative sequence filter current reference and the filter current negative sequence vector. By performing negative-sequence voltage compensation on the inverter voltage of the three-phase three-leg structure connected to the micro-power supply and the DC bus, the purpose of compensating the negative-sequence voltage component in the three-phase voltage of the DC bus is achieved, and the load is avoided. Fault. In addition, the invention also discloses a micro-grid negative sequence voltage compensation device for an inverter-interfaced micro-source, which has the same effect as above.

Description

technical field [0001] The invention relates to the field of micro-grids, in particular to a micro-grid negative-sequence voltage compensation method and device for inverter-interfaced micro-sources. Background technique [0002] Under the severe situation of energy shortage and environmental pollution, in recent years, distributed generation technology has made great progress in research, development and utilization. In order to give full play to the advantages and potential of distributed power generation, the concept of micro-grid was proposed. Micro-grid refers to a small power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, related loads, monitoring and protection devices. A system is an autonomous system capable of self-control and management. Among them, the micro-grid contains various forms of micro-power sources, such as solar energy, wind energy, biomass energy, etc., and the interface fo...

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Problems solved by technology

[0003] Among them, the micro-power supply of the micro-grid is connected to the DC bus through the inverter interface, and the voltage provided by the micro-power in the micro-grid is provided to each load or connected to the large power grid through the DC bus. However, due to environmental factors, the micro-power output The voltage to the DC bus is asymmetrical, and when the DC bus voltage is asymmetrical, a negative sequence component of the voltage will appear

The negative-sequence voltage components that appear when the DC bus voltage is asymmetrical will directly affect the normal operation of each load, and in severe cases will cause load failure. Currently, there is a relative There are relatively mature negative sequence voltage compensation methods, but there are few studies on the negative sequence voltage compensation of inverter interface type micro-sources with three-phase three-leg structure. The negative-sequence voltage compensation of the micro-source will lead to asymmetrical voltage output to the DC bus. The negative-sequence voltage component of the voltage that appears when the DC bus voltage is asymmetrical will directly affect the normal operation of each load, and in severe cases will cause load failure.

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