SMES-Battery Energy Storage System for the Stabilization of a Photovoltaic-Based Microgrid

As superconducting magnetic energy storage (SMES) and battery are complementary in their technical properties of power capacity, energy density, response speed, etc., this paper proposes an SMES-battery energy storage system to stabilize a photovoltaic-based microgrid under different faults. The related theoretical modeling is stated, and the control and coordination methods of the SMES-battery are put forward. Using MATLAB, a comparison of with the SMES-battery and only with the battery is carried out. From the main specifications of the SMES magnet, the ac-loss calculation is also performed. The results show that i) the SMES-battery is better than the battery to timely deal with the transient faults of the microgrid; ii) the SMES-battery enables to ensure a seamless mode-transition for the microgrid under the external fault, and reduce the fault current in the point of common coupling to avoid an unnecessary off-grid under the internal fault; and iii) the SMES magnet's ac-loss power has a maximum value of 380 W, and it is acceptable for the future design of conduction-cooled structure and cryogenic system.