An extended adaptive detection method and its application in power quality improvement

This paper intensively investigates an active noise cancellation method's application in power quality improvement applications. The original algorithm in acoustic area is first introduced and then extended to current harmonic selective detection. The adaptive algorithm identifies amplitudes, phases and frequencies of fundamental and harmonic components from nonlinear load current. The identified results are used to generate control reference for power quality improvement control. The current harmonic selective feature lies in its ability to estimate any specific harmonics. The extended algorithm is fully tested both in simulation and experiment. It is also compared with traditional d-q transformation based harmonic detection method. And this method is found to have advantages such as internal frequency tracking, easy application to single phase and three phase unbalanced systems, simple and flexible. At last, an active filter application example shows the effectiveness of this proposed adaptive method in power quality application.