【摘要】 分析了传统定步长最小均方(LMS)算法用于谐波电流检测的不足,采用一种新的变步长LMS自适应算法检测谐波电流:根据误差信号e(n)和e(n-D)的自相关估计调整步长迭代,当权系数远离最佳权值时,通过增大步长加快对时变系统的跟踪速度;当权系数接近最佳权值时,减小步长获得较小的稳态误差。通过递推公式参数的选择,可对系统的收敛速度与稳态失调进行更灵活的控制。推导出了该方法的理论表达公式,其增加的计算量很小,容易实现。该方法能有效调节步长,不受谐波电流的干扰。仿真结果证明了该谐波电流检测方法的有效性。更多还原

【Abstract】 Based on the study of disadvantages of conventional fixed step-size LMS(Least Mean Square) algorithm for harmonic current detection,an adaptive LMS algorithm with variable step-size is provided,which adjusts the step-size according to the autocorrelation estimation between e(n) and e(n-D).When the weight is far away from the optimal value,it increases the step-size to acce-lerate the tracking of time-variable system,while when the weight is near the optimal value,it decreases the step-size to minish the steady state error.By selecting appropriate parameters,the algorithm allows more flexible control of misadjustment and faster convergence speed.Its theore-tical approximate expressions are derived.It is easy to be implemented with little additional calculation.The algorithm can effectively adjust the step-size while maintaining the immunity against harmonic current disturbance.Simulation results illustrate its effectiveness.更多还原