The transmission of new energy through voltage source converter based high voltage DC (VSC-HVDC) is a future development trend

but it generally fails to offer frequency support for the power grid. Conventional methods lower DC voltage to signal frequency drops

which may overload IGBTs due to rapidly rising arm currents. This paper proposes an active frequency support control strategy based on a reverse frequency-DC voltage mapping mechanism. The strategy prevents active power encroachment during DC boosting via dual-terminal submodule energy control and arm voltage clamping. While conveying grid frequency drop information

it suppresses arm current growth

enhances flexible DC transmission capacity

and significantly strengthens both the grid-support capability of renewable energy delivery systems via flexible DC and grid frequency stability. Based on PSCAD/EMTDC

a photovoltaic island transmission model is established through a VSC-HVDC system. Tests under load surge scenarios demonstrated its effectiveness in delivering inertial response and dynamic frequency regulation.