Power transfer of direct current with inductive couplings

A method of transmitting electrical power to equipment at a remote subsea location, the method comprising:

• transmitting DC electrical power from a source of DC electrical power over an electrically conductive power transmssion cable to the remote subsea location;
• distinguishing between DC electrical power of a first polarity and an opposite, second polarity;
• at the remote location, converting the DC electrical power of either the first or second polarities to AC electrical power having a frequency in at least the kilohertz range;
• and,
• transmitting the AC electrical power across a magnetically coupled, selectively separable inductive coupler which is electrically connected with the remotely located equipment to provide electrical power thereto.

An apparatus for transmitting electrical power to equipment within a subsea module at a remote location, the apparatus comprising:

• a source of DC electrical power;
• a power transmission cable extending from the source of DC electrical power to the remote location;
• a first rectifying means adjacent the remote location and operatively connected with the power transmission cable for limiting the passage of power therethrough to DC power of a first polarity;
• a first DC to AC inverter means adjacent the remote location for converting the first polarity electrical power to AC electrical power having a frequency in at least the kilohertz range;
• and,
• a subsea inductive coupler having selectively separable first and second magnetically coupled portions, the first coupler portion being operatively connected with the DC to AC inverter means for receiving the AC electrical power therefrom and transferring the power magnetically to the second inductive coupler portion, the remotely located equipment being operatively connected with the second inductive coupler portion.