Grid current low-order harmonics suppression of the three-phase grid converter with an LCL filter under the distorted grid voltage

Abstract

This article presents an extended backstepping control method to reduce the grid-side current harmonics caused by grid voltage distortion. A dynamic model considering the grid voltage as an external disturbance is derived in the stationary reference frame. The extended back-stepping design procedure based on pole displacement guarantees that the system is stable without damping. The proposed method has a general low-order harmonics suppression instead of selective harmonics elimination. Zero steady-state error can be obtained tracking the grid currents. Stability, as well as good transient and steady-state performance are verified through numerical simulation. A comparison with the state-of-the-art proportional resonant control with active damping is also conducted. The results show that a good low-order harmonics reduction in the grid current is achieved by the proposed control method.

Keywords

• power grids
• power filters
• control system synthesis
• damping
• control nonlinearities
• electric current control
• closed loop systems
• DC-AC power convertors
• invertors
• harmonics suppression
• power system harmonics
• nonlinear control systems
• state-of-the-art proportional resonant control
• steady-state performance
• zero steady-state error
• selective harmonics elimination
• general low-order harmonics suppression
• pole displacement guarantees
• stationary reference frame
• grid voltage distortion
• grid-side current harmonics
• extended backstepping control method
• distorted grid voltage
• LCL filter
• three-phase grid converter
• grid current low-order harmonics suppression
• low-order harmonics reduction