Control and Stability Analysis of Multi-Parallel Single-Phase Electric Springs

To expand the capacity of electric spring (ES) and improve the ability of critical load voltage control, a multi-ES parallel structure is proposed. Concerning the control and operation stability problem of multi-parallel ESs, a method to realize reactive power compensation in the parallel system is advanced, and the stability of the system is studied. Firstly, the topology of the multi-ES parallel system and the phase control strategy suitable for the structure are introduced. Then, by applying impedance modeling, the mathematical models of a single ES and its parallel system are established, and the impact of controller parameters on the stability of the system is discussed by utilizing impedance analysis method. Finally, the correctness of the theoretical analysis is verified by the establishment of a simulation model with three-parallel ESs.