基于无源性的光伏并网逆变器非线性电流控制策略

Nonlinear Current Control Strategy Based on Passivity of Photovoltaic Grid-Connected Inverter

鉴于光伏并网逆变器的数学模型呈现非线性特性,采用无源控制(Passivity-Based Control,PBC)理论得出的算法对逆变器进行控制,可使并网逆变器具备优良的动、静态特性。论文首先建立了并网逆变器欧拉-拉格朗日(Euler-Lagrange,EL)数学模型,证明了逆变器是严格无源的。基于逆变器的无源性,控制能量在逆变器中的重新分布,并采用注入阻尼和系统解耦的方法对控制器进行了优化设计。控制器对输出有功电流和无功电流分别进行控制,使系统能快速跟踪光伏阵列的最大功率点,同样也可对本地负载进行无功功率补偿。计算机仿真表明,基于无源性的光伏并网逆变器非线性电流控制策略是可行的。

In view of the nonlinear of mathematical model of the photovoltaic grid-connected inverter,passivity-based control（PBC） is adopted to control inverter,thus the inverter can possesses excellent dynamic and static characteristics.First the Euler-Lagrange（EL） model of inverter is established,which is proved strictly passive.Based on passivity of inverter,the system energy is redistributed.The approaches of damping injection and system decoupling are adopted to optimize passivity-based controller.The active and reactive current of system are controlled to realize the PV array maximum power point FastTrack and compensating the reactive power of local load.Simulation results show that passivity-based control method is practicable.