An Electric Spring Without Noncritical Load Based on Fractional-Order Components

Electric springs (ESs) have been proposed as a new emerging distributed demand-response technology that can be used to solve the problem of voltage fluctuations caused by intermittent renewable energy power generation. In order to ensure the voltage stability of critical loads (CLs), most of ESs are connected in series with noncritical loads (NCLs) so that the transferring fluctuating energy can be transferred to NCLs. However, the effective operating range of ES is limited by the voltage withstood by NCL. In this article, after analyzing the influence of NCL on the operating range of ES, a fractional-order ES is proposed, which can regulate the voltage of CL without NCL. The proposed ES is based on the characteristic that fractional-order components can consume or release active power under different orders. Topology, operating principle, and voltage regulation range of proposed fractional-order ES together with control method are detailed. The effectiveness of fractional-order ES has been verified via simulation and experimental results.