A Novel Control Method of Low-voltage-ride-through Technique for Asymmetrical Hybrid Energy Storage System

Abstract Low-voltage-ride-through (LVRT) capability is an important criterion for the stability of cascaded multilevel energy storage system (ESS). Based on asymmetrical hybrid ESS, a coordinated operating method is proposed to maintain the phase angle of positive-sequence-voltage of battery cells and capacitor cells. To deal with the asymmetrical chains among three phases, its influence on the power distribution is eliminated by modifying the command of battery cells, then the traditional zero-sequence-voltage injection is feasible for asymmetrical situations. Proposed methods can stabilize the dc-side voltage of capacitor cells, maintaining the output current. Finally, the correctness and effectiveness of proposed methods are proved by experiment.