Power sharing and circulating current suppression control of M-SMES based on AVSG

Abstract

By integrating multiple superconducting magnetic energy storage units (SMESU), the multi-superconducting magnetic energy storage system (M-SMES) facilitates the capacity expansion and standardization of energy storage systems. However, during parallel operation, parameter and dynamic mismatches among units often cause uneven power sharing and circulating currents. To address this, an adaptive virtual synchronous generator (AVSG) control method was proposed to achieve stable operation. First, the power transfer characteristics of M-SMES and the circulating current characteristics arising from the cascaded converter structure were analyzed. Second, a coordinated control strategy for the cascaded converters was designed accordingly. The front-stage DC/DC chopper employs voltage-current dual-loop control to guarantee DC-link voltage stability, while the rear-stage DC/AC inverter adopts adaptive inertia and damping control to ensure efficient and stable power delivery, thereby achieving effective active power sharing and reducing active circulating currents. Subsequently, the virtual complex impedance was dynamically adjusted based on the reactive power deviation to accomplish reactive power sharing and suppress reactive circulating currents. Finally, simulation results of a three-unit parallel system on the Matlab/Simulink platform verify the superior performance of the proposed strategy in power sharing and circulating current suppression.

Keywords

M-SMES / power sharing / circulation suppression / virtual synchronous generator / adaptive control

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