Harmonic suppression method and system in charging process of electric vehicle in grid-connected state

Abstract

The invention discloses a harmonic suppression method and system in the charging process of an electric vehicle in a grid-connected state. The harmonic suppression method in the charging process of the electric vehicle in the grid-connected state comprises the following steps: obtaining expected charging current corresponding to the model of the electric vehicle and a change controllable range corresponding to the expected charging current; detecting charging current in the charging process of the electric vehicle, and judging whether harmonic current exists in the charging current or not; if so, obtaining a comparison result of the difference between the detected charging current and the expected charging current and the change controllable range; and when the comparison result shows that the difference exceeds the change controllable range, filtering out harmonic current in the charging current in real time through an active power filter. The method and the system have a good harmonic suppression effect, selectively processes harmonic waves, improve the stability of a power grid, and prolong the service life of parts of the power grid.

Description

technical field [0001] The invention relates to the technical field of electric vehicle charging, in particular to a harmonic suppression method and system in the charging process of electric vehicles in a grid-connected state. Background technique [0002] With the development of science and technology, electric vehicles, as a new generation of transportation, have incomparable advantages in energy saving and emission reduction compared to traditional vehicles. However, when an electric vehicle is connected to the grid as a nonlinear load for charging, it will generate harmonics, which will affect the power quality and cause poor power quality. What's more, it will cause the spring of the microgrid system to fail to work normally. It is very necessary to control the harmonics generated by car charging. [0003] At this stage, the method of harmonic control adopts the method of necessary removal. As we all know, the use of charging and discharging components has a certain s...

AI Technical Summary

Problems solved by technology

However, when an electric vehicle is connected to the grid as a nonlinear load for charging, it will generate harmonics, which will affect the power quality and cause poor power quality. What's more, it will cause the spring of the microgrid system to fail to work normally. It is very necessary to control the harmonics generated by car charging

[0003] At this stage, the method of harmonic control adopts the method of necessary removal. It is well known that the use of charging and discharging components has a certain service life. After a certain period of use, the charging and discharging components will be damaged. If the current The harmonics are weak and have no effect on the charging of electric vehicles. If the continuous processing will cause waste of resources

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