Self-adaptive decoupling control method for improving inertia supporting capacity of flexible direct current system

The invention relates to a self-adaptive decoupling control method for improving inertia supporting capacity of a flexible direct current system, and belongs to the technical field of flexible direct current power transmission. Analyzing available energy margin in the flexible direct current system, and establishing a coupling relation between the receiving end power grid and the direct current voltage; a receiving-end converter station and a sending-end converter station adaptive modulation strategy based on local measurement information is designed, the input number of sub-modules is adaptively adjusted without communication, effective decoupling of direct-current voltage and sub-module capacitor voltage is achieved, the operation range of the sub-module capacitor voltage is widened while it is guaranteed that the direct-current voltage does not exceed the limit, and the stability of the direct-current voltage is improved. The energy margin of the capacitor in the flexible direct current system is fully uti