SHIELDING ARRANGEMENTS FOR TRANSFORMER STRUCTURES
Shielding arrangements for transformer structures capable for operation in high frequency and high power density applications are disclosed. Electric shields may be incorporated within transformers to shield and/or redirect high strength electric fields away from areas of insulation material that may be prone to failure mechanisms. Such electric shields may be positioned between primary and secondary windings in order to be coupled with electric potentials of the windings. The electric shield may comprise a laminate structure that includes one or more metal layers and one or more dielectric layers, for example a printed circuit board. By positioning the electric shields in this manner, high electric fields associated with solid state transformer applications may be concentrated within planes of the electric shields and diverted away from potential problem areas, for example areas that are close to the windings where voids in the insulation material may otherwise promote failure mechanisms.
1 . A transformer comprising:
a primary winding;
a secondary winding;
an insulation material arranged between the primary winding and the secondary winding; and
at least one electric shield positioned at least partially within the insulation material and between the primary winding and the secondary winding.
2 . The transformer of claim 1 , wherein the at least one electric shield comprises at least one metal layer and at least one dielectric material, the at least one metal layer residing on the at least one dielectric material or within the at least one dielectric material.
3 . The transformer of claim 2 , wherein the at least one metal layer comprises a plurality of metal layers, a first metal layer of the plurality of metal layers is on the at least one dielectric material, and a second metal layer of the plurality of metal layers is within the at least one dielectric material.
4 . The transformer of claim 3 , wherein the first metal layer is arranged closer to one of the primary winding or the secondary winding than the second metal layer, the first metal layer being arranged to extend a distance that corresponds to at least a longest dimension of the primary winding or the secondary winding, and the second metal layer is arranged to extend a distance that is greater than the first metal layer.
5 . The transformer of claim 1 , wherein the at least one electric shield comprises a printed circuit board.
6 . The transformer of claim 1 , wherein the at least one electric shield comprises a first electric shield that is coupled with an electric potential of the primary winding and a second electric shield that is coupled with an electric potential of the secondary winding.
7 . The transformer of claim 1 , wherein the at least one electric shield is completely encapsulated within the insulation material.
8 . The transformer of claim 1 , further comprising a coil former that at least partially defines a shape of at least one of the primary winding and the secondary winding.
9 . The transformer of claim 8 , wherein the coil former and the at least one electric shield define the shape of at least one of the primary winding and the secondary winding.
10 . The transformer of claim 8 , wherein the coil former forms at least one opening that supports at least a portion of the at least one electric shield.
11 . The transformer of claim 1 , further comprising a magnetic core, wherein the insulation material, the primary winding, the secondary winding, and the at least one electric shield form a winding package, the winding package forming a central opening, and a portion of the magnetic core resides within the central opening.
12 . The transformer of claim 11 , wherein the primary winding forms a winding turn along a corner of the winding package and the at least one electric shield extends past the winding turn.
13 . The transformer of claim 11 , further comprising at least one thermal plate arranged between the winding package and the magnetic core.
14 . The transformer of claim 1 , wherein the primary winding is configured as a medium voltage winding and the secondary winding is configured as a low voltage winding.
15 . The transformer of claim 1 , wherein at least one of the primary winding and the secondary winding comprises multiple-strand wiring.
16 . The transformer of claim 1 , wherein at least one of the primary winding and the secondary winding comprises a foil structure.
17 . The transformer of claim 1 , wherein the insulation material comprises a viscosity in a range from 2500 centipoise (cP) to 5000 cP.
18 . A solid state transformer comprising:
a first voltage stage;
a second voltage state; and
an isolation stage arranged between the first voltage stage and the second voltage stage, the isolation stage comprising:
a transformer comprising a primary winding, a secondary winding, an insulation material arranged between the primary winding and the secondary winding, and at least one electric shield positioned between the primary winding and the secondary winding.
19 . The solid state transformer of claim 18 , wherein the at least one electric shield is encapsulated within the insulation material.
20 . The solid state transformer of claim 18 , wherein the at least one electric shield comprises a printed circuit board.
21 . The solid state transformer of claim 18 , wherein at least one of the first voltage stage and the second voltage stage comprises a wide band gap switching device.
22 . The solid state transformer of claim 21 , wherein the wide band gap switching device comprises a silicon carbide switching device.
23 . The solid state transformer of claim 18 , wherein the isolation stage comprises a wide band gap switching device.
24 . The solid state transformer of claim 23 , wherein the wide band gap switching device comprises a silicon carbide switching device.
25 . The solid state transformer of claim 18 , wherein the first voltage stage comprises a medium voltage stage electrically connected to the primary winding, and the second voltage stage comprises a low voltage stage electrically coupled to the secondary winding.
26 . The solid state transformer of claim 18 , wherein the solid state transformer is rated for operation up to 485 kilovolt-amperes.
27 . The solid state transformer of claim 18 , wherein the insulation material comprises a viscosity in a range from 2500 centipoise (cP) to 5000 cP.