Offshore wind power flexible DC output voltage penetration control method, device and system

The invention discloses an offshore wind power flexible DC output voltage penetration control method, device and system, and the method comprises the steps: collecting a real-time voltage signal at an AC side of a land station; and processing the acquired voltage signal to generate a modulation signal, and controlling the alternating current side of the AC/DC converter of the offshore station through the modulation signal, so that the voltage of the offshore wind plant participates in the frequency modulation of the power grid. After the control method is adopted, the direct-current power transmission system shows the transparent characteristic in grid connection from the offshore wind plant to the land alternating-current power grid. During normal operation, the offshore wind power plant can normally participate in power grid frequency modulation like being directly connected into an alternating current power grid. When an onshore alternating-current power grid breaks down, the offshore wind power plant can