A higher-order filter approach to implement grid current based active damping in active front end converters

摘要

Active damping (AD) based on grid current feedback is a desirable option to deal with the LCL filter resonance issues, however, practical implementations can be problematical due to noise amplifications associated with the derivatives in the active damping term. To mitigate the noise amplification problem, this paper introduces a fourth-order filter for the practical implementation of grid current feedback AD in active front end (AFE) converter applications. In addition, to ensure stability and damp the resonant frequency, an active damping implementation approach using the proposed filter along with the control design is included in this paper. The proposed method is verified by way of extensive simulation. Additionally, specific practical problems as grid inductance uncertainty and digital delay effects on proposed control are investigated.