A Dual-Mode Grid-Connected Control Strategy for a Bidirectional Power Converter

At present, control strategies are designed for AC/DC hybrid microgrid grid-connected operation under the condition that AC distribution network is strong grid (ideal grid). However, with the access of high-density distributed power supply, the distribution network gradually presents the weak grid condition. In order to make the bidirectional power converter run stably in both strong and weak grid conditions, this paper proposes a two-mode control strategy in grid-connected mode based on short-circuit ratio identification, voltage source control, current source control and system inertia. Finally, the simulation results show the effectiveness of the proposed method.