Resonance Suppression Strategy for Multi-parallel Inverters Based on Adaptive Filtering

Abstract

Inverters are the core devices of renewable power generation systems. However, their negative impedance character may induce resonance, seriously affecting power quality and endangering safe operation of power networks. To solve this problem, an equivalent impedance model of the inverter in voltage control mode is established. Then the relationship between the negative impedance character and control delay is quantitatively analyzed, pointing out that the negative impedance character will be weakened with control delay decrease. On this basis, a resonance suppression strategy based on adaptive filtering algorithm is proposed. By reducing equivalent control delay, the impedance of the inverter is reshaped and therefore resonance suppression is realized. Finally, effectiveness of the proposed control strategy is verified with simulation and experiment.