Comprehensive series compensation voltage ride-through device of wind turbine generator and control method

Abstract

The invention discloses a comprehensive series compensation voltage ride-through device of a wind turbine generator. The comprehensive series compensation voltage ride-through device of the wind turbine generator is mounted on a three-phase circuit between a wind driven generator and a control device of the wind driven generator and a PCC (point of common coupling) of a power grid, and comprises a three-phase standard transducer, a series coupling transformer, a two-way charge-discharge circuit, a DC bus capacitor and a by-pass switch. With the adoption of a dynamic voltage restorer, a chopper circuit and a super capacitor with high-capacity energy storage in the power electronic technology, low voltage ride through, high voltage ride through and harmonic compensation are realized under the condition that generator terminal voltage drops off during power grid fault, generator terminal voltage rises due to excessive reactive power of the power grid and the harmonic content of the power grid is overlarge, the wind turbine generator is prevented from being separated from the grid, and harmful effects of harmonic are prevented; and moreover, a conventional wind turbine generator is not required to be transformed, and the device can be taken as an independent control module and added at the stator output port of the wind turbine generator and is convenient to mount.

Description

technical field [0001] The invention relates to the technical field of wind power generation voltage ride through, in particular to the low / high voltage ride through (Low / High voltage ride through, LVRT / HVRT) of wind power generators and the smooth torque fluctuation control technology under the condition of harmonic distortion of grid voltage. Background technique [0002] Wind farms are generally located in remote locations, far away from the load center. In the past, in order to protect wind turbines, wind farms generally avoided the impact of grid failure on wind turbines by frequent shutdown. With the increasing installed capacity of wind turbines, the traditional self-protection of wind turbines will have a significant impact on the safe and stable operation of the power grid, especially in the case of disturbances and faults in the power system, its impact on the power system will become more and more serious. Prominent, serious faults will cause the grid voltage to c...

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Problems solved by technology

[0005] Technical problems to be solved: Aiming at the deficiencies of the prior art, the comprehensive series compensation voltage ride-through device and control method for wind turbines of the present invention solve the following three technical problems in the prior art: (1) When the grid fault causes a voltage drop, The wind turbine is disconnected from the grid due to lack of low-voltage ride-through capability; (2) After the grid fault is removed, the excess reactive power causes the system voltage to rise, and the wind turbine is disconnected from the grid due to overvoltage protection, that is, the high-voltage ride-through capability is poor; (3 ) In the case of grid voltage harmonic distortion, negative effects such as output power fluctuations, current harmonics, and continuous torque pulsation will cause great harm to the shaft transmission system of the wind turbine gearbox

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