Low-voltage ride through circuit of double-feed type wind power generator

Abstract

The invention relates to a low-voltage ride through circuit of a double-feed type wind power generator, which utilizes a superconducting magnet as an energy storing core. A superconducting magnet is charged and discharged, active power provided by a double-feed type wind power generator is adjusted in a normal state, and the active power provided by the wind power generator is smoothed, thereby improving the electric energy quality of wind power generation, reducing influence to a power grid and compensating the fluctuation of the active power output by a wind power generating system. When the voltage of the power grid is abnormal, a compensating voltage is connected in series between the power grid and a stator of the double-feed type wind power generator through a transformer and a current source inverter circuit, therefore, the voltage of the stator end of the double-feed type wind power generator maintains a normal state, the wind power generating system can be still run online when the wind power generating system generates voltage temporary reduction, and thereby the low-voltage ride through requirement of a power system on the wind power generator is met.

Description

technical field [0001] The invention relates to a low-voltage ride-through circuit of a double-fed wind power generator. Background technique [0002] Wind power is developing rapidly around the world, and its proportion in the power grid is gradually increasing. As the proportion of wind power in the power grid continues to increase, the impact of wind power on power grid stability and power quality is increasing. In order to reduce the impact of wind power generation on the power grid, countries around the world have gradually introduced grid-connected standards for wind power generation, one of which is to require wind turbines to exit the power grid when they meet certain requirements at low voltage. In order to meet the requirements of low-voltage grid connection, various low-voltage ride-through technologies are gradually developed. Various low-voltage ride-through technologies are mainly divided into two types: 1. Adopt fault protection circuit. like figure 1 As s...

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Problems solved by technology

The above two methods can play a certain role, but still have the following deficiencies: 1. The current fault protection circuit needs to trigger the corresponding circuit to protect after detecting the fault signal, so it has a certain delay and cannot play a role. The role of complete protection

2. Adopting an improved control method needs to increase the capacity of the converter, and there is nothing that can be done when the voltage drops deeply

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