Método de estimação de parâmetros para conversores VSC conectados à rede

Abstract

Grid-connected converters work in a stable and optimized way if their voltage and current control loops are tuned specifically to that grid for which they were designed. This tuning is directly related to the grid impedance at the point the converter is connected to. So, it is desirable that the converter itself be capable to identify the grid impedance and be able to tune its control loop gains without further operator adjustments. Thinking on that, it is proposed an algorithm capable to calculate the parameters of grid impedance injecting a reference signal in CHIRP shape to the grid through current-controlled voltage sourced converted (VSC). With these parameters on hand, the converter can dynamically tune its control loop gains. So, the main contribution of this dissertation consists on evaluating a method that involves the use of a recursive algorithm that is capable to calculate the grid impedance parameters without disconnecting the VSC converter from the grid. This algorithm defines the grid impedance in a fast way while consuming few memory and processing time.