Study on the Working Mode and Impedance-Based Stability Criterion of Generalized Electric Spring

When the electric spring (ES) is used in the face of critical load clustering, the repetitive ES parallel structure introduces significant redundancy into the system. To address this issue, this paper further investigates the concept and topology of generalized electric spring(G-ES), analyzes the working model of G-ES, and discusses in depth the working mode of G-ES under the two cases of unidirectional and bidirectional power supply. The control strategy of the G-ES is designed to achieve current feedforward compensation through the load factor. The stability of G-ES is studied based on impedance analysis, and the stability criterion of G-ES under weak grid conditions is given. The results show that there are 100 working modes of the G-ES. The simulations and experiments are conducted to verify the correctness of the control method and stability impedance criterion proposed in this paper.