A subsea AC power supply device comprises a subsea transformer, having a primary winding arranged to be connected to a topside AC power supply via a subsea power supply cable, and a subsea shunt reactor, connected in parallel with the primary winding of the subsea transformer. The subsea transformer and the subsea shunt reactor are arranged within a common subsea watertight housing. A subsea AC power supply system comprises a topside AC power supply, a subsea power supply cable connected to the topside AC power supply, and a subsea AC power supply device connected to the subsea power supply cable.

A cooling structure for a first electromagnetic coil includes the first electromagnetic coil having a space extending in the direction of a predetermined axis Z; a cooling member attached to an end surface, with respect to the direction of the predetermined axis Z, of the first electromagnetic coil and having a flow path for fluid internally formed; and an inlet pipe and an outlet pipe connected, within the space, to an inlet and outlet, respectively, of the flow path of the cooling member and extending through the space to a region outside the electromagnetic coil.

A cooling structure for a first electromagnetic coil includes the first electromagnetic coil having a space extending in the direction of a predetermined axis Z; a cooling member attached to an end surface, with respect to the direction of the predetermined axis Z, of the first electromagnetic coil and having a flow path for fluid internally formed; and an inlet pipe and an outlet pipe connected, within the space, to an inlet and outlet, respectively, of the flow path of the cooling member and extending through the space to a region outside the electromagnetic coil.

According to some embodiments, subsea fault tolerant transformer includes an arrangement of two tanks mounted one above the other. A lower tank houses the transformer windings and core and is below and abutting an upper tank. Both tanks are filled with respective dielectric oil. The electrical terminals for the primary and secondary power connections are on the second/instrument tank and the conductors pass through the instrument tank and then through the shared wall to the transformer tank. The design allows for enhanced cooling of the transformer through a single wall portion of the lower tank as well as fault tolerance associated with double barriers.

According to some embodiments, subsea fault tolerant transformer includes an arrangement of two tanks mounted one above the other. A lower tank houses the transformer windings and core and is below and abutting an upper tank. Both tanks are filled with respective dielectric oil. The electrical terminals for the primary and secondary power connections are on the second/instrument tank and the conductors pass through the instrument tank and then through the shared wall to the transformer tank. The design allows for enhanced cooling of the transformer through a single wall portion of the lower tank as well as fault tolerance associated with double barriers.

An inductive device includes a toroidal core and at least one electric conductor wound around the toroidal core and constituting at least one winding. The inductive device includes a cooling element constituting a cylindrical cavity that contains the toroidal core and the electric conductor so that the axial direction of the toroidal core is parallel with the axial direction of the cylindrical cavity. The shape of the cylindrical cavity and the cross-section of the electric conductor are adapted to match each other so as to improve heat transfer from the electric conductor to the wall of the cylindrical cavity. The cylindrical cavity can have for example a circular base and the electric conductor can have for example a rectangular cross-section that matches the shape of the wall of the cylindrical cavity better than a round electric conductor.

An inductive device includes a toroidal core and at least one electric conductor wound around the toroidal core and constituting at least one winding. The inductive device includes a cooling element constituting a cylindrical cavity that contains the toroidal core and the electric conductor so that the axial direction of the toroidal core is parallel with the axial direction of the cylindrical cavity. The shape of the cylindrical cavity and the cross-section of the electric conductor are adapted to match each other so as to improve heat transfer from the electric conductor to the wall of the cylindrical cavity. The cylindrical cavity can have for example a circular base and the electric conductor can have for example a rectangular cross-section that matches the shape of the wall of the cylindrical cavity better than a round electric conductor.

Invention described herein relates to wireless power transfer systems and methods that efficiently and safely transfer power to electronic devices. In an aspect of the invention, an apparatus for wirelessly receiving power is provided. The apparatus comprises a receiver circuit comprising a receiver coil configured to receive wireless power from a wireless power transmitter via a magnetic field sufficient to charge or power a load of the apparatus. The receiver circuit further comprises a ferrite material having a first side coupled to the receiver coil. The apparatus further comprises a first heat exchanger coupled to a second side of the ferrite material.

An electrical device for connecting to a high-voltage power grid has a boiler, which is filled with an insulating fluid and in which a magnetizable core and at least one winding, which surrounds a section of the core, are arranged, and a cooling system which includes at least one radiator which is arranged outside the boiler and is connected thereto via the radiator in order to circulate the insulating fluid, wherein the radiator has at least two heat exchange elements which are connected in parallel with one another. In order to enable a cold start to be accelerated and to be carried out even at relatively low temperatures only one of the heat exchange elements has a heat-conducting connection, as a heated heat exchange element, to a heat source which generates heat when the operation of the electrical device is started.

An electrical device for connecting to a high-voltage power grid has a boiler, which is filled with an insulating fluid and in which a magnetizable core and at least one winding, which surrounds a section of the core, are arranged, and a cooling system which includes at least one radiator which is arranged outside the boiler and is connected thereto via the radiator in order to circulate the insulating fluid, wherein the radiator has at least two heat exchange elements which are connected in parallel with one another. In order to enable a cold start to be accelerated and to be carried out even at relatively low temperatures only one of the heat exchange elements has a heat-conducting connection, as a heated heat exchange element, to a heat source which generates heat when the operation of the electrical device is started.