Weighted Average Current control in three-phase grid inverter with LCL-filter

Abstract

A novel control method, named Weighted Average Current control (WACC) is proposed for damping control of three-phase grid inverter with LCL-filter. With WACC, three-phase current control of the grid inverter can be decoupled under synchronous rotating frame (SRF). Besides the system transfer function is degraded from the 6th order system to the 1st order one. Consequently, the control loop gain and bandwidth can be increased. Therefore the current control of the grid system is able to be optimized easily for higher power quality and good dynamics. WACC is verified with the experiment on a 30kW three-phase grid inverter prototype.