A Novel Electric Spring Based On Passively Damped Lcl Filter

Electric spring (ES) is an emerging power quality adjustment method that can effectively solve the power quality problem, especially voltage fluctuations caused by renewable energy sources. However, the existing topologies of ES have the shortcoming of limited compensation range due to their structure, in which ES is in series with non-critical load (NCL). In this paper, a novel ES is proposed based on a passively damped LCL filter. Unlike the existing ES topologies, LCL-ES employs NCL to implement passive damping of LCL filter, which not only overcomes the passive damping but also extends the compensation range. Besides, the key points on topology design and control strategy are discussed. Finally, the effectiveness of the proposed LCL-ES has been verified via simulation.