有源电力滤波器半矢量预测控制策略研究

Research on Semi-vector Predictive Control Strategy of Active Power Filter

针对经典模型预测电流控制算法电压矢量选择范围有限、电流跟踪精度不高的问题,提出改进型模型预测电压控制算法。利用滚动寻优得到较优电压矢量,再利用较优电压矢量和零矢量各作用Ts/2得到半幅值矢量,根据较优电压矢量和半幅值矢量的评价函数选择最优电压矢量。每个周期仅增加一个电压矢量,能有效减小预测电压矢量和实际电压矢量之间的误差,实现对谐波电流的准确跟踪,提高有源电力滤波器的补偿性能。仿真结果表明,所提出的改进型模型预测电压控制算法与经典模型预测电流控制算法相比,补偿电流对参考电流的跟踪更加准确,经补偿后并网电流中的谐波含量由4.86%下降到3.32%,且在稳态和动态情况下都能实现单位功率因数并网。

Aiming at the problems of limited selection range of voltage vector and low accuracy of current tracking in the classical model predictive current control algorithm, an improved model predictive voltage control algorithm was proposed. The better voltage vector was obtained by rolling optimization, and using Ts/2 for the better voltage vector and Ts/2 for zero vector to achieve the half amplitude vector. The optimal voltage vector was chosen according to the evaluation function of the two vectors. Adding only one voltage vector per period could effectively reduce the error between predicted voltage vector and actual voltage vector, realized the accurate tracking of harmonic current, and improved the compensation performance of active power filter. Simulation results showed the proposed improved model predictive voltage control algorithm is more accurate than the classical model predictive current control algorithm in tracking the reference current. After compensation, the harmonic content in the grid-connected current decreases from 4.86% to 3.32%, and the grid-connected unit power factor can be achieved under both steady-state and dynamic conditions.