Research on a novel adaptive current detecting method based on internal model theory

Conventional adaptive current detection methods are always terribly disturbed by the “mutual erroneous impacts”, which are due to the low SNR (Signal-to-Noise Ratio) utility conditions, so it is difficult to make an optimal tradeoff between the speed and accuracy of those adaptive methods. This paper has proposed a novel adaptive current detection method, where a sliding integration filter (SIF) was applied to eliminate the disturbances by other current components and to derive the real amplitude estimation errors of target current components. Then, adaptive detection closed-loop systems were constructed based on the internal model theory so as to extract the target current components from the distorted load current rapidly and accurately. The mathematical model of the proposed adaptive method was presented, and its performances including system convergence, dynamic and steady-state responses were also illustrated by analytic methods of control theory so that theoretical instructions could be provide for designing the adaptive current detection method. Finally, simulation and experimental results of the proposed novel detection method and previous methods are compared, which verify the correctness and effectiveness of the proposed theory and method.