A Novel Fundamental and Harmonics Detection Method Based on State-Space Model for Power Electronics System

Harmonic current estimation is the key technology of power electronics systems to generate a harmonics reference current for harmonic control. In this paper, a novel fundamental and harmonic current detection method based on the state-space model (SSM) is introduced. The proposed SSM harmonics detection method has the ability to detect the positive sequence component (PSC), negative sequence component (NSC), and zero-sequence component (ZSC) of both fundamental and each order harmonics current with fast response and high accuracy separately, including the fundamental component, which is appealing for harmonics control in power electronic applications, such as active power filter (APF), unified power quality conditioner (UPQC), virtual synchronous generator (VSG), and so on. The correctness of the proposed SSM based harmonics detection method has been verified by simulation and experiment result, and it shows that the PSC, NSC, and ZCS of the grid fundamental and high order harmonic current can be detected q uickly and accurately, which is important for harmonics analysis and control in the power electronics system.