A Digital Method for Detecting Harmonic Currents Based on Instantaneous Reactive Power Theory
The choice of the cut-off frequency reflects a tradeoff between maladjustment and the speed of dynamic response in the conventional detection method based on instantaneous reactive power theory. The paper proposes a novel digital real-time algorithm for detecting harmonic currents. This algorithm adopts a new variable step size least mean square(LMS) adaptive filter as LPF on harmonic detection circuit. The step-size is large when the algorithm is far from the optimum with decreasing as it approaches the optimum. The proposed algorithm allows more flexible control of misadjustment and fast convergence rate without the need to compromise one for the other. Meanwhile approximate theoretical expressions for the behavior of the algorithm are derived. The additional calculation is very little, so the algorithm presented is easy to implement. Simulation and experiment results illustrate that the performance of the proposed approach is satisfactory.
Harmonic detectinginstantaneous reactive power theoryadaptive filtervariable step-size
国家科技期刊平台
NSTL
万方数据
维普
