Current Controller for LCL-Type Grid-Following Inverter with Active Damping and Capacitor Voltage Decoupling

This paper proposes a current control strategy for grid-following inverters interfaced into the grid through LCL filters. It is proposed to utilize a proportional+resonant controller with a lead compensation in series with the proportional gain which allows the inverter to achieve high bandwidth. Furthermore, an active damping scheme with capacitor current feedback is applied to mitigate the adverse effect of the LCL filter resonance frequency. Moreover, the concept of capacitor voltage decoupling is utilized to enhance the disturbance rejection capability of the grid-following inverter. Theoretical analysis and experimental results validate the proposed strategy.