Hybrid MMC virtual inertia control strategy based on transient and steady state cooperation

The invention discloses a hybrid MMC virtual inertia control strategy based on transient and steady state cooperation in the technical field of modular multilevel converters. The control strategy comprises a direct current loop with a virtual inductance control strategy and an alternating current loop with a virtual capacitance control strategy. According to the control strategy, the inertia of the capacitor voltage of the sub-module under the direct-current fault can be increased, so that the capacitor voltage quickly returns to a set value, the inertia of the direct-current voltage under the steady-state load fluctuation can be increased, and the anti-interference capability is enhanced; the short-circuit current in the transient process can be reduced to 40% of the original short-circuit current, the capacitor voltage fluctuation peak value of the sub-module is reduced to half of the original capacitor voltage fluctuation peak value, the direct-current voltage fluctuation is reduced ...