A DC-Type Dynamic Voltage Restorer Based on Hybrid Energy Storage

Conceptual design and performance evaluation of a DC-type dynamic voltage restorer (DVR) system are presented for mitigation of DC voltage quality disturbances in various sensitive-load situations such as in electric vehicle charging stations and data centers. A 3-mH/225-A superconducting magnetic energy storage (SMES) coil is introduced to cooperate with conventional battery energy storage (BES) device for developing a new hybrid energy storage (HES) system in the DCtype DVR. Various simulation cases with regard to combined voltage sag and swell disturbances are carried out. The simulations and comparisons among the SMES-based, BESbased and HES-based DVR schemes have demonstrated that the HES-based DVR scheme integrates the merits of fast response speed and high power density from the SMES-based scheme and the merits of low capital cost and high energy density from the BES-based scheme.