灰色预测控制在三电平4桥臂APF中的应用

Application of Gray Prediction Control in Three-level Four-leg APF

三相4线制系统的中线电流、谐波、无功功率问题日益严重,有源电力滤波器以其优良的性能成为电力系统谐波抑制和无功补偿的重要手段。针对APF控制方法复杂的问题,在建立其数学模型的基础上提出一种应用于三电平三相4桥臂APF的灰色预测控制策略。该方法在k时刻对负载电流和补偿电流进行采样,经过GM(1,1)模型得出k+l时刻的预测谐波电流,使输出补偿电流尽量接近指令电流,达到补偿谐波的目的。仿真结果表明:此方法可以有效地补偿系统的谐波电流和中线电流,自适应能力强,控制精度高,鲁棒性强,在三相4线制系统中具有良好的应用前景。

Nowdays,neutral current, harmonics current and reactive power is becoming increasingly serious in three- phase four-wire system, active power filter becomes an important means of harmonic suppression and reactive power compensation for its excellent performance. According to the complex control problem, based on the mathematic model,gray predictive control was proposed to control the three-level three- phase four-leg APF.Load current and compensated current are sampled at time k,the forecasted harmonic current is obtained at time k＋l after GM（1,1） model.The output compensated current approaehs the command current as close as possible to achieve the purpose of harmonic compensation. Simulation results illustrate that the control strategy can compensate the harmonic current and neutral current effectively, and has higher self adaptive ability and high control precision, as well as strong robustness. The control strategy has a good application prospect in the three-phase four-wire system.