Single-phase controllable series compensation device applied to low voltage ride through of fans

Abstract

The invention discloses a single-phase controllable series compensation device applied to low voltage ride through of fans. The device comprises a three-phase four-wire bridge type circuit, two sets of discharging circuits, a pre-charging circuit, three sets of filtering circuits, three single-phase isolation transformers and three bypass switches. The single-phase controllable series compensation device is applied to wind fields and connected between each fan and fan grid connection points in series, after system faults are removed, net dragging of the fans is caused by voltage drop of the grid connection points, the overcurrent and overvoltage failure problem of a fan converter happens, and the fans can meet the requirement for low voltage ride through capacity of the nation. The core of the series compensation device is the three-phase four-wire bridge type circuit, an output voltage of a circuit is coupled to circuits by a filter through the transformers, each phase is independent, independent compensation can be performed according to different characteristics of three-phase voltages, and finally, three-phase end voltages connected to the fans have the best compensation effect; part of active power sent by the fans is consumed by the discharging circuits of the device in the compensation voltage period.

Description

technical field [0001] The invention relates to the field of low-voltage ride-through of wind turbines, and more specifically relates to a single-phase controllable series compensation device applied to low-voltage ride-through of wind turbines. Background technique [0002] At present, major developed countries and developing countries in the world have taken the development of renewable energy such as wind energy and solar energy as an important means to deal with the dual challenges of energy and climate change in the new century. However, among all renewable energy sources except water energy, wind energy is undoubtedly one of the most commercialized renewable energy technologies recognized in the world. Wind energy has a good industrialization foundation and the most obvious economic advantages, and there is no biomass energy constraints without any major environmental impact. [0003] Double-fed wind turbines are currently the mainstream models installed in wind farms...

AI Technical Summary

Problems solved by technology

In the way of grid-connected installation, the stator side of the double-fed fan is directly connected to the grid through the transformer, which is more sensitive to the system voltage. When a short-circuit fault occurs in the system, the voltage at the grid-connected point of the fan will drop, which will directly affect the rotor of the double-fed fan. side voltage and current parameters, if no control strategy or protection measures are taken, the DFIG rotor converter will fail due to overcurrent and overvoltage

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