A Comprehensive Inertial Control Strategy for Hybrid AC/DC Microgrid with Distributed Generations

Lack of inertia is one problem urgent for the stability of hybrid ac/dc system. In this paper, a comprehensive inertial control strategy is proposed for stability improvement of the hybrid ac/dc microgrid. The unified inertia index is introduced to evaluate the holistic inertia level of the hybrid microgrid. Besides, the coupling relationship between ac and dc nanogrid is discussed based on the power balance, which serves as the base of mutual inertial support. The characteristics of distributed generations (DGs) are analyzed, based on which the comprehensive inertial support is designed for various DGs respectively and adaptively divided into two responses: the local support and the cross-grid support. The proposed strategy takes full use of the rotational kinetic energy of wind turbine generator (WTG), and exploits the power capacity of distributed hybrid energy storages (HESs), which improves the global stability and dynamic performance of the hybrid microgrid during power disturbance. The performance of the proposed control strategy is validated by the simulation cases with different operating scenarios.