Resonance damping of LCL filter based grid-connected inverter

Abstract

Three-phase PWM inverters are connected to the grid by an LC or an LCL filter. Although an LCL filter is more effective since it more efficiently attenuates the switching harmonics, but it causes stability problems. To enable a stable operation, either a damping resistor or an active damping algorithm has to be used. However, while a damping resistor causes additional losses, to avoid these disadvantages, this paper shows simulation results of a simple active damping solution which is suitable for industrial applications.