新能源并网导则规定风电机组在故障期间需向电网注入一定的无功电流,而现有的控制策略为满足穿越性能要求,只单一考虑最大化定子侧变流器或网侧变流器(grid side converter,GSC)的无功电流输出,易加重转子电流过流与直流母线电压越限.首先分析安全范围内GSC与转子侧变流器(rotor side converter,RSC)可提供的最大可用无功功率;然后采用基于径向基函数(radial basis function,RBF)神经网络的PID(proportion-integral-differential)自校正控制器,以恢复电压为目的,计算所需无功功率补偿的参考值;再进而综合考虑容量、控制参考值与穿越性能指标,提出一种考虑动态无功支撑的双馈风电机组协调控制策略,实现对GSC与RSC的合理无功需求分配.仿真结果表明:所提协调控制策略在双馈风力发电机(doubly-fed induction generator,DFIG)故障期间有良好的穿越性能和无功支撑效果.
Coordinated control strategy of doubly-fed induction generator considering dynamic reactive power support
New energy grid-connected guidelines stipulate that wind turbines need to inject a certain amount of reactive current into the grid during fault period.However,the existing control strategies only consider maximizing the reactive current output of the stator side converter or grid-side converter(GSC)in order to meet the ride-through performance requirements,which is easy to exacerbate the overcurrent of rotor currents and the overrun of DC bus voltages.Firstly,the maximum available reactive power that can be provided by the GSC and rotor side converter(RSC)within the safety range is analysed.The proportion-integration-differentiation(PID)self-correcting controller based on radial basis function(RBF)neural network is then used to calculate the reference value of the required reactive power compensation with the purpose of voltage recovery.Then,a coordinated control strategy for doubly-fed wind turbine considering the capacity,control reference value and ride-through performance indexes is proposed to realize the reasonable reactive power demand allocation between GSC and RSC.Simulation results show that the proposed coordinated control strategy has good ride-through performance and reactive power support effect during doubly-fed induction generator(DFIG)failures.
doubly-fed induction generatorlow-voltage ride-throughreactive power supportcoordinated control
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