An active damper for stabilizing power-electronics-based AC systems

The interactions among the parallel grid-connected converters coupled through the grid impedance tend to result in stability and power quality problems. To address them, this paper proposes an active damper based on a high bandwidth power electronics converter. The general idea behind this proposal is to dynamically reshape the grid impedance profile seen from the point of common coupling of the converters, such that the potential oscillations and resonance propagation in the parallel grid-connected converters can be mitigated. To validate the effectiveness of the active damper, simulations and experimental tests on a three-converter-based setup are carried out. The results show that the active damper can become a promising way to stabilize the power-electronics-based ac power systems.